Merge branch 'develop' into feature/2.0tsdb

.gitignore

@@ -46,7 +46,6 @@ html/
 /CMakeCache.txt
 /Makefile
 /*.cmake
-/deps
 /src/cq/test/CMakeFiles/cqtest.dir/*.cmake
 *.cmake
 /src/cq/test/CMakeFiles/cqtest.dir/*.make
@@ -65,3 +64,4 @@ CMakeError.log
 /out/isenseconfig/WSL-Clang-Debug
 /out/isenseconfig/WSL-GCC-Debug
 /test/cfg
+/src/.vs

CMakeSettings.json

@@ -5,7 +5,7 @@
       "generator": "Unix Makefiles",
       "configurationType": "Debug",
       "buildRoot": "${projectDir}\\build\\",
-      "installRoot": "${projectDir}\\out\\install\\${name}",
+      "installRoot": "${projectDir}\\build\\",
       "cmakeExecutable": "/usr/bin/cmake",
       "cmakeCommandArgs": "",
       "buildCommandArgs": "",

deps/CMakeLists.txt

@@ -7,3 +7,4 @@ ADD_SUBDIRECTORY(regex)
 ADD_SUBDIRECTORY(iconv)
 ADD_SUBDIRECTORY(lz4)
 ADD_SUBDIRECTORY(cJson)
+ADD_SUBDIRECTORY(MQTT-C)

deps/MQTT-C/CMakeLists.txt

+cmake_minimum_required(VERSION 3.5)
+project(MQTT-C VERSION 1.1.2 LANGUAGES C)
+
+# MQTT-C build options
+option(MQTT_C_OpenSSL_SUPPORT "Build MQTT-C with OpenSSL support?" OFF)
+option(MQTT_C_MbedTLS_SUPPORT "Build MQTT-C with mbed TLS support?" OFF)
+option(MQTT_C_EXAMPLES "Build MQTT-C examples?" ON)
+option(MQTT_C_TESTS "Build MQTT-C tests?" OFF)
+
+list (APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
+
+# MQTT-C library
+add_library(mqttc STATIC 
+    src/mqtt_pal.c
+    src/mqtt.c
+)
+target_include_directories(mqttc PUBLIC include)
+target_link_libraries(mqttc PUBLIC 
+    $<$<C_COMPILER_ID:MSVS>:ws2_32>
+)
+
+
+# Configure with OpenSSL support
+if(MQTT_C_OpenSSL_SUPPORT)
+    find_package(OpenSSL REQUIRED)
+    target_link_libraries(mqttc INTERFACE OpenSSL::SSL)
+    target_compile_definitions(mqttc PUBLIC MQTT_USE_BIO)
+endif()
+
+# Configure with mbed TLS support
+if(MQTT_C_MbedTLS_SUPPORT)
+    find_package(MbedTLS REQUIRED)
+    target_include_directories(mqttc PUBLIC ${MBEDTLS_INCLUDE_DIRS})
+    target_link_libraries(mqttc INTERFACE ${MBEDTLS_LIBRARY})
+    target_compile_definitions(mqttc PUBLIC MQTT_USE_MBEDTLS)
+endif()
+
+# Build examples
+if(MQTT_C_EXAMPLES)
+    find_package(Threads REQUIRED)
+
+    if(MQTT_C_OpenSSL_SUPPORT)
+        add_executable(bio_publisher examples/bio_publisher.c)
+        target_link_libraries(bio_publisher Threads::Threads mqttc)
+
+        add_executable(openssl_publisher examples/openssl_publisher.c)
+        target_link_libraries(openssl_publisher Threads::Threads mqttc)
+    elseif(MQTT_C_MbedTLS_SUPPORT)
+        add_executable(mbedtls_publisher examples/mbedtls_publisher.c)
+        target_link_libraries(mbedtls_publisher Threads::Threads mqttc ${MBEDX509_LIBRARY} ${MBEDCRYPTO_LIBRARY})
+    else()
+        add_executable(simple_publisher examples/simple_publisher.c)
+        target_link_libraries(simple_publisher Threads::Threads mqttc)
+
+        add_executable(simple_subscriber examples/simple_subscriber.c)
+        target_link_libraries(simple_subscriber Threads::Threads mqttc)
+
+        add_executable(reconnect_subscriber examples/reconnect_subscriber.c)
+        target_link_libraries(reconnect_subscriber Threads::Threads mqttc)
+    endif()
+endif()
+
+# Build tests
+if(MQTT_C_TESTS)    
+    find_path(CMOCKA_INCLUDE_DIR cmocka.h)
+    find_library(CMOCKA_LIBRARY cmocka)
+    if((NOT CMOCKA_INCLUDE_DIR) OR (NOT CMOCKA_LIBRARY))
+        message(FATAL_ERROR "Failed to find cmocka! Add cmocka's install prefix to CMAKE_PREFIX_PATH to resolve this error.")
+    endif()
+
+    add_executable(tests tests.c)
+    target_link_libraries(tests ${CMOCKA_LIBRARY} mqttc)
+    target_include_directories(tests PRIVATE ${CMOCKA_INCLUDE_DIR})
+endif()
+
+# Install includes and library
+# install(TARGETS mqttc 
+#     DESTINATION lib
+# )
+# install(DIRECTORY include/
+#    DESTINATION include)

deps/MQTT-C/Doxyfile

+# Doxyfile 1.8.11
+
+# This file describes the settings to be used by the documentation system
+# doxygen (www.doxygen.org) for a project.
+#
+# All text after a double hash (##) is considered a comment and is placed in
+# front of the TAG it is preceding.
+#
+# All text after a single hash (#) is considered a comment and will be ignored.
+# The format is:
+# TAG = value [value, ...]
+# For lists, items can also be appended using:
+# TAG += value [value, ...]
+# Values that contain spaces should be placed between quotes (\" \").
+
+#---------------------------------------------------------------------------
+# Project related configuration options
+#---------------------------------------------------------------------------
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+# built into libc) for the transcoding. See http://www.gnu.org/software/libiconv
+# for the list of possible encodings.
+# The default value is: UTF-8.
+
+DOXYFILE_ENCODING      = UTF-8
+
+# The PROJECT_NAME tag is a single word (or a sequence of words surrounded by
+# double-quotes, unless you are using Doxywizard) that should identify the
+# project for which the documentation is generated. This name is used in the
+# title of most generated pages and in a few other places.
+# The default value is: My Project.
+
+PROJECT_NAME           = "MQTT-C"
+
+# The PROJECT_NUMBER tag can be used to enter a project or revision number. This
+# could be handy for archiving the generated documentation or if some version
+# control system is used.
+
+PROJECT_NUMBER         =
+
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+# for a project that appears at the top of each page and should give viewer a
+# quick idea about the purpose of the project. Keep the description short.
+
+PROJECT_BRIEF          =
+
+# With the PROJECT_LOGO tag one can specify a logo or an icon that is included
+# in the documentation. The maximum height of the logo should not exceed 55
+# pixels and the maximum width should not exceed 200 pixels. Doxygen will copy
+# the logo to the output directory.
+
+PROJECT_LOGO           =
+
+# The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute) path
+# into which the generated documentation will be written. If a relative path is
+# entered, it will be relative to the location where doxygen was started. If
+# left blank the current directory will be used.
+
+OUTPUT_DIRECTORY       = docs/
+
+# If the CREATE_SUBDIRS tag is set to YES then doxygen will create 4096 sub-
+# directories (in 2 levels) under the output directory of each output format and
+# will distribute the generated files over these directories. Enabling this
+# option can be useful when feeding doxygen a huge amount of source files, where
+# putting all generated files in the same directory would otherwise causes
+# performance problems for the file system.
+# The default value is: NO.
+
+CREATE_SUBDIRS         = NO
+
+# If the ALLOW_UNICODE_NAMES tag is set to YES, doxygen will allow non-ASCII
+# characters to appear in the names of generated files. If set to NO, non-ASCII
+# characters will be escaped, for example _xE3_x81_x84 will be used for Unicode
+# U+3044.
+# The default value is: NO.
+
+ALLOW_UNICODE_NAMES    = NO
+
+# The OUTPUT_LANGUAGE tag is used to specify the language in which all
+# documentation generated by doxygen is written. Doxygen will use this
+# information to generate all constant output in the proper language.
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+# Chinese-Traditional, Croatian, Czech, Danish, Dutch, English (United States),
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+# Korean, Korean-en (Korean with English messages), Latvian, Lithuanian,
+# Macedonian, Norwegian, Persian (Farsi), Polish, Portuguese, Romanian, Russian,
+# Serbian, Serbian-Cyrillic, Slovak, Slovene, Spanish, Swedish, Turkish,
+# Ukrainian and Vietnamese.
+# The default value is: English.
+
+OUTPUT_LANGUAGE        = English
+
+# If the BRIEF_MEMBER_DESC tag is set to YES, doxygen will include brief member
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+# documentation (similar to Javadoc). Set to NO to disable this.
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+
+BRIEF_MEMBER_DESC      = YES
+
+# If the REPEAT_BRIEF tag is set to YES, doxygen will prepend the brief
+# description of a member or function before the detailed description
+#
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+# brief descriptions will be completely suppressed.
+# The default value is: YES.
+
+REPEAT_BRIEF           = YES
+
+# This tag implements a quasi-intelligent brief description abbreviator that is
+# used to form the text in various listings. Each string in this list, if found
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+# and the result, after processing the whole list, is used as the annotated
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+# following values are used ($name is automatically replaced with the name of
+# the entity):The $name class, The $name widget, The $name file, is, provides,
+# specifies, contains, represents, a, an and the.
+
+ABBREVIATE_BRIEF       =
+
+# If the ALWAYS_DETAILED_SEC and REPEAT_BRIEF tags are both set to YES then
+# doxygen will generate a detailed section even if there is only a brief
+# description.
+# The default value is: NO.
+
+ALWAYS_DETAILED_SEC    = NO
+
+# If the INLINE_INHERITED_MEMB tag is set to YES, doxygen will show all
+# inherited members of a class in the documentation of that class as if those
+# members were ordinary class members. Constructors, destructors and assignment
+# operators of the base classes will not be shown.
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+
+INLINE_INHERITED_MEMB  = NO
+
+# If the FULL_PATH_NAMES tag is set to YES, doxygen will prepend the full path
+# before files name in the file list and in the header files. If set to NO the
+# shortest path that makes the file name unique will be used
+# The default value is: YES.
+
+FULL_PATH_NAMES        = YES
+
+# The STRIP_FROM_PATH tag can be used to strip a user-defined part of the path.
+# Stripping is only done if one of the specified strings matches the left-hand
+# part of the path. The tag can be used to show relative paths in the file list.
+# If left blank the directory from which doxygen is run is used as the path to
+# strip.
+#
+# Note that you can specify absolute paths here, but also relative paths, which
+# will be relative from the directory where doxygen is started.
+# This tag requires that the tag FULL_PATH_NAMES is set to YES.
+
+STRIP_FROM_PATH        =
+
+# The STRIP_FROM_INC_PATH tag can be used to strip a user-defined part of the
+# path mentioned in the documentation of a class, which tells the reader which
+# header file to include in order to use a class. If left blank only the name of
+# the header file containing the class definition is used. Otherwise one should
+# specify the list of include paths that are normally passed to the compiler
+# using the -I flag.
+
+STRIP_FROM_INC_PATH    =
+
+# If the SHORT_NAMES tag is set to YES, doxygen will generate much shorter (but
+# less readable) file names. This can be useful is your file systems doesn't
+# support long names like on DOS, Mac, or CD-ROM.
+# The default value is: NO.
+
+SHORT_NAMES            = NO
+
+# If the JAVADOC_AUTOBRIEF tag is set to YES then doxygen will interpret the
+# first line (until the first dot) of a Javadoc-style comment as the brief
+# description. If set to NO, the Javadoc-style will behave just like regular Qt-
+# style comments (thus requiring an explicit @brief command for a brief
+# description.)
+# The default value is: NO.
+
+JAVADOC_AUTOBRIEF      = NO
+
+# If the QT_AUTOBRIEF tag is set to YES then doxygen will interpret the first
+# line (until the first dot) of a Qt-style comment as the brief description. If
+# set to NO, the Qt-style will behave just like regular Qt-style comments (thus
+# requiring an explicit \brief command for a brief description.)
+# The default value is: NO.
+
+QT_AUTOBRIEF           = NO
+
+# The MULTILINE_CPP_IS_BRIEF tag can be set to YES to make doxygen treat a
+# multi-line C++ special comment block (i.e. a block of //! or /// comments) as
+# a brief description. This used to be the default behavior. The new default is
+# to treat a multi-line C++ comment block as a detailed description. Set this
+# tag to YES if you prefer the old behavior instead.
+#
+# Note that setting this tag to YES also means that rational rose comments are
+# not recognized any more.
+# The default value is: NO.
+
+MULTILINE_CPP_IS_BRIEF = NO
+
+# If the INHERIT_DOCS tag is set to YES then an undocumented member inherits the
+# documentation from any documented member that it re-implements.
+# The default value is: YES.
+
+INHERIT_DOCS           = YES
+
+# If the SEPARATE_MEMBER_PAGES tag is set to YES then doxygen will produce a new
+# page for each member. If set to NO, the documentation of a member will be part
+# of the file/class/namespace that contains it.
+# The default value is: NO.
+
+SEPARATE_MEMBER_PAGES  = NO
+
+# The TAB_SIZE tag can be used to set the number of spaces in a tab. Doxygen
+# uses this value to replace tabs by spaces in code fragments.
+# Minimum value: 1, maximum value: 16, default value: 4.
+
+TAB_SIZE               = 4
+
+# This tag can be used to specify a number of aliases that act as commands in
+# the documentation. An alias has the form:
+# name=value
+# For example adding
+# "sideeffect=@par Side Effects:\n"
+# will allow you to put the command \sideeffect (or @sideeffect) in the
+# documentation, which will result in a user-defined paragraph with heading
+# "Side Effects:". You can put \n's in the value part of an alias to insert
+# newlines.
+
+ALIASES                =
+
+# This tag can be used to specify a number of word-keyword mappings (TCL only).
+# A mapping has the form "name=value". For example adding "class=itcl::class"
+# will allow you to use the command class in the itcl::class meaning.
+
+TCL_SUBST              =
+
+# Set the OPTIMIZE_OUTPUT_FOR_C tag to YES if your project consists of C sources
+# only. Doxygen will then generate output that is more tailored for C. For
+# instance, some of the names that are used will be different. The list of all
+# members will be omitted, etc.
+# The default value is: NO.
+
+OPTIMIZE_OUTPUT_FOR_C  = YES
+
+# Set the OPTIMIZE_OUTPUT_JAVA tag to YES if your project consists of Java or
+# Python sources only. Doxygen will then generate output that is more tailored
+# for that language. For instance, namespaces will be presented as packages,
+# qualified scopes will look different, etc.
+# The default value is: NO.
+
+OPTIMIZE_OUTPUT_JAVA   = NO
+
+# Set the OPTIMIZE_FOR_FORTRAN tag to YES if your project consists of Fortran
+# sources. Doxygen will then generate output that is tailored for Fortran.
+# The default value is: NO.
+
+OPTIMIZE_FOR_FORTRAN   = NO
+
+# Set the OPTIMIZE_OUTPUT_VHDL tag to YES if your project consists of VHDL
+# sources. Doxygen will then generate output that is tailored for VHDL.
+# The default value is: NO.
+
+OPTIMIZE_OUTPUT_VHDL   = NO
+
+# Doxygen selects the parser to use depending on the extension of the files it
+# parses. With this tag you can assign which parser to use for a given
+# extension. Doxygen has a built-in mapping, but you can override or extend it
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+# instance to make doxygen treat .inc files as Fortran files (default is PHP),
+# and .f files as C (default is Fortran), use: inc=Fortran f=C.
+#
+# Note: For files without extension you can use no_extension as a placeholder.
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+# Note that for custom extensions you also need to set FILE_PATTERNS otherwise
+# the files are not read by doxygen.
+
+EXTENSION_MAPPING      =
+
+# If the MARKDOWN_SUPPORT tag is enabled then doxygen pre-processes all comments
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+# mix doxygen, HTML, and XML commands with Markdown formatting. Disable only in
+# case of backward compatibilities issues.
+# The default value is: YES.
+
+MARKDOWN_SUPPORT       = YES
+
+# When enabled doxygen tries to link words that correspond to documented
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+# globally by setting AUTOLINK_SUPPORT to NO.
+# The default value is: YES.
+
+AUTOLINK_SUPPORT       = YES
+
+# If you use STL classes (i.e. std::string, std::vector, etc.) but do not want
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+
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+# If you use Microsoft's C++/CLI language, you should set this option to YES to
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+
+CPP_CLI_SUPPORT        = NO
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+# Set the SIP_SUPPORT tag to YES if your project consists of sip (see:
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+
+SIP_SUPPORT            = NO
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+# For Microsoft's IDL there are propget and propput attributes to indicate
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+
+IDL_PROPERTY_SUPPORT   = YES
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+DISTRIBUTE_GROUP_DOC   = NO
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+
+SUBGROUPING            = YES
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+# The default value is: NO.
+
+INLINE_SIMPLE_STRUCTS  = NO
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+TYPEDEF_HIDES_STRUCT   = NO
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+LOOKUP_CACHE_SIZE      = 0
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+EXTRACT_PRIVATE        = NO
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+EXTRACT_PACKAGE        = NO
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+# If the EXTRACT_STATIC tag is set to YES, all static members of a file will be
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+EXTRACT_STATIC         = NO
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+# If the EXTRACT_LOCAL_CLASSES tag is set to YES, classes (and structs) defined
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+# The default value is: NO.
+
+EXTRACT_LOCAL_METHODS  = NO
+
+# If this flag is set to YES, the members of anonymous namespaces will be
+# extracted and appear in the documentation as a namespace called
+# 'anonymous_namespace{file}', where file will be replaced with the base name of
+# the file that contains the anonymous namespace. By default anonymous namespace
+# are hidden.
+# The default value is: NO.
+
+EXTRACT_ANON_NSPACES   = NO
+
+# If the HIDE_UNDOC_MEMBERS tag is set to YES, doxygen will hide all
+# undocumented members inside documented classes or files. If set to NO these
+# members will be included in the various overviews, but no documentation
+# section is generated. This option has no effect if EXTRACT_ALL is enabled.
+# The default value is: NO.
+
+HIDE_UNDOC_MEMBERS     = NO
+
+# If the HIDE_UNDOC_CLASSES tag is set to YES, doxygen will hide all
+# undocumented classes that are normally visible in the class hierarchy. If set
+# to NO, these classes will be included in the various overviews. This option
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+# The default value is: NO.
+
+HIDE_UNDOC_CLASSES     = NO
+
+# If the HIDE_FRIEND_COMPOUNDS tag is set to YES, doxygen will hide all friend
+# (class|struct|union) declarations. If set to NO, these declarations will be
+# included in the documentation.
+# The default value is: NO.
+
+HIDE_FRIEND_COMPOUNDS  = NO
+
+# If the HIDE_IN_BODY_DOCS tag is set to YES, doxygen will hide any
+# documentation blocks found inside the body of a function. If set to NO, these
+# blocks will be appended to the function's detailed documentation block.
+# The default value is: NO.
+
+HIDE_IN_BODY_DOCS      = NO
+
+# The INTERNAL_DOCS tag determines if documentation that is typed after a
+# \internal command is included. If the tag is set to NO then the documentation
+# will be excluded. Set it to YES to include the internal documentation.
+# The default value is: NO.
+
+INTERNAL_DOCS          = NO
+
+# If the CASE_SENSE_NAMES tag is set to NO then doxygen will only generate file
+# names in lower-case letters. If set to YES, upper-case letters are also
+# allowed. This is useful if you have classes or files whose names only differ
+# in case and if your file system supports case sensitive file names. Windows
+# and Mac users are advised to set this option to NO.
+# The default value is: system dependent.
+
+CASE_SENSE_NAMES       = YES
+
+# If the HIDE_SCOPE_NAMES tag is set to NO then doxygen will show members with
+# their full class and namespace scopes in the documentation. If set to YES, the
+# scope will be hidden.
+# The default value is: NO.
+
+HIDE_SCOPE_NAMES       = NO
+
+# If the HIDE_COMPOUND_REFERENCE tag is set to NO (default) then doxygen will
+# append additional text to a page's title, such as Class Reference. If set to
+# YES the compound reference will be hidden.
+# The default value is: NO.
+
+HIDE_COMPOUND_REFERENCE= NO
+
+# If the SHOW_INCLUDE_FILES tag is set to YES then doxygen will put a list of
+# the files that are included by a file in the documentation of that file.
+# The default value is: YES.
+
+SHOW_INCLUDE_FILES     = YES
+
+# If the SHOW_GROUPED_MEMB_INC tag is set to YES then Doxygen will add for each
+# grouped member an include statement to the documentation, telling the reader
+# which file to include in order to use the member.
+# The default value is: NO.
+
+SHOW_GROUPED_MEMB_INC  = NO
+
+# If the FORCE_LOCAL_INCLUDES tag is set to YES then doxygen will list include
+# files with double quotes in the documentation rather than with sharp brackets.
+# The default value is: NO.
+
+FORCE_LOCAL_INCLUDES   = NO
+
+# If the INLINE_INFO tag is set to YES then a tag [inline] is inserted in the
+# documentation for inline members.
+# The default value is: YES.
+
+INLINE_INFO            = YES
+
+# If the SORT_MEMBER_DOCS tag is set to YES then doxygen will sort the
+# (detailed) documentation of file and class members alphabetically by member
+# name. If set to NO, the members will appear in declaration order.
+# The default value is: YES.
+
+SORT_MEMBER_DOCS       = YES
+
+# If the SORT_BRIEF_DOCS tag is set to YES then doxygen will sort the brief
+# descriptions of file, namespace and class members alphabetically by member
+# name. If set to NO, the members will appear in declaration order. Note that
+# this will also influence the order of the classes in the class list.
+# The default value is: NO.
+
+SORT_BRIEF_DOCS        = NO
+
+# If the SORT_MEMBERS_CTORS_1ST tag is set to YES then doxygen will sort the
+# (brief and detailed) documentation of class members so that constructors and
+# destructors are listed first. If set to NO the constructors will appear in the
+# respective orders defined by SORT_BRIEF_DOCS and SORT_MEMBER_DOCS.
+# Note: If SORT_BRIEF_DOCS is set to NO this option is ignored for sorting brief
+# member documentation.
+# Note: If SORT_MEMBER_DOCS is set to NO this option is ignored for sorting
+# detailed member documentation.
+# The default value is: NO.
+
+SORT_MEMBERS_CTORS_1ST = NO
+
+# If the SORT_GROUP_NAMES tag is set to YES then doxygen will sort the hierarchy
+# of group names into alphabetical order. If set to NO the group names will
+# appear in their defined order.
+# The default value is: NO.
+
+SORT_GROUP_NAMES       = NO
+
+# If the SORT_BY_SCOPE_NAME tag is set to YES, the class list will be sorted by
+# fully-qualified names, including namespaces. If set to NO, the class list will
+# be sorted only by class name, not including the namespace part.
+# Note: This option is not very useful if HIDE_SCOPE_NAMES is set to YES.
+# Note: This option applies only to the class list, not to the alphabetical
+# list.
+# The default value is: NO.
+
+SORT_BY_SCOPE_NAME     = NO
+
+# If the STRICT_PROTO_MATCHING option is enabled and doxygen fails to do proper
+# type resolution of all parameters of a function it will reject a match between
+# the prototype and the implementation of a member function even if there is
+# only one candidate or it is obvious which candidate to choose by doing a
+# simple string match. By disabling STRICT_PROTO_MATCHING doxygen will still
+# accept a match between prototype and implementation in such cases.
+# The default value is: NO.
+
+STRICT_PROTO_MATCHING  = NO
+
+# The GENERATE_TODOLIST tag can be used to enable (YES) or disable (NO) the todo
+# list. This list is created by putting \todo commands in the documentation.
+# The default value is: YES.
+
+GENERATE_TODOLIST      = YES
+
+# The GENERATE_TESTLIST tag can be used to enable (YES) or disable (NO) the test
+# list. This list is created by putting \test commands in the documentation.
+# The default value is: YES.
+
+GENERATE_TESTLIST      = YES
+
+# The GENERATE_BUGLIST tag can be used to enable (YES) or disable (NO) the bug
+# list. This list is created by putting \bug commands in the documentation.
+# The default value is: YES.
+
+GENERATE_BUGLIST       = YES
+
+# The GENERATE_DEPRECATEDLIST tag can be used to enable (YES) or disable (NO)
+# the deprecated list. This list is created by putting \deprecated commands in
+# the documentation.
+# The default value is: YES.
+
+GENERATE_DEPRECATEDLIST= YES
+
+# The ENABLED_SECTIONS tag can be used to enable conditional documentation
+# sections, marked by \if <section_label> ... \endif and \cond <section_label>
+# ... \endcond blocks.
+
+ENABLED_SECTIONS       =
+
+# The MAX_INITIALIZER_LINES tag determines the maximum number of lines that the
+# initial value of a variable or macro / define can have for it to appear in the
+# documentation. If the initializer consists of more lines than specified here
+# it will be hidden. Use a value of 0 to hide initializers completely. The
+# appearance of the value of individual variables and macros / defines can be
+# controlled using \showinitializer or \hideinitializer command in the
+# documentation regardless of this setting.
+# Minimum value: 0, maximum value: 10000, default value: 30.
+
+MAX_INITIALIZER_LINES  = 30
+
+# Set the SHOW_USED_FILES tag to NO to disable the list of files generated at
+# the bottom of the documentation of classes and structs. If set to YES, the
+# list will mention the files that were used to generate the documentation.
+# The default value is: YES.
+
+SHOW_USED_FILES        = YES
+
+# Set the SHOW_FILES tag to NO to disable the generation of the Files page. This
+# will remove the Files entry from the Quick Index and from the Folder Tree View
+# (if specified).
+# The default value is: YES.
+
+SHOW_FILES             = YES
+
+# Set the SHOW_NAMESPACES tag to NO to disable the generation of the Namespaces
+# page. This will remove the Namespaces entry from the Quick Index and from the
+# Folder Tree View (if specified).
+# The default value is: YES.
+
+SHOW_NAMESPACES        = YES
+
+# The FILE_VERSION_FILTER tag can be used to specify a program or script that
+# doxygen should invoke to get the current version for each file (typically from
+# the version control system). Doxygen will invoke the program by executing (via
+# popen()) the command command input-file, where command is the value of the
+# FILE_VERSION_FILTER tag, and input-file is the name of an input file provided
+# by doxygen. Whatever the program writes to standard output is used as the file
+# version. For an example see the documentation.
+
+FILE_VERSION_FILTER    =
+
+# The LAYOUT_FILE tag can be used to specify a layout file which will be parsed
+# by doxygen. The layout file controls the global structure of the generated
+# output files in an output format independent way. To create the layout file
+# that represents doxygen's defaults, run doxygen with the -l option. You can
+# optionally specify a file name after the option, if omitted DoxygenLayout.xml
+# will be used as the name of the layout file.
+#
+# Note that if you run doxygen from a directory containing a file called
+# DoxygenLayout.xml, doxygen will parse it automatically even if the LAYOUT_FILE
+# tag is left empty.
+
+LAYOUT_FILE            =
+
+# The CITE_BIB_FILES tag can be used to specify one or more bib files containing
+# the reference definitions. This must be a list of .bib files. The .bib
+# extension is automatically appended if omitted. This requires the bibtex tool
+# to be installed. See also http://en.wikipedia.org/wiki/BibTeX for more info.
+# For LaTeX the style of the bibliography can be controlled using
+# LATEX_BIB_STYLE. To use this feature you need bibtex and perl available in the
+# search path. See also \cite for info how to create references.
+
+CITE_BIB_FILES         =
+
+#---------------------------------------------------------------------------
+# Configuration options related to warning and progress messages
+#---------------------------------------------------------------------------
+
+# The QUIET tag can be used to turn on/off the messages that are generated to
+# standard output by doxygen. If QUIET is set to YES this implies that the
+# messages are off.
+# The default value is: NO.
+
+QUIET                  = NO
+
+# The WARNINGS tag can be used to turn on/off the warning messages that are
+# generated to standard error (stderr) by doxygen. If WARNINGS is set to YES
+# this implies that the warnings are on.
+#
+# Tip: Turn warnings on while writing the documentation.
+# The default value is: YES.
+
+WARNINGS               = YES
+
+# If the WARN_IF_UNDOCUMENTED tag is set to YES then doxygen will generate
+# warnings for undocumented members. If EXTRACT_ALL is set to YES then this flag
+# will automatically be disabled.
+# The default value is: YES.
+
+WARN_IF_UNDOCUMENTED   = YES
+
+# If the WARN_IF_DOC_ERROR tag is set to YES, doxygen will generate warnings for
+# potential errors in the documentation, such as not documenting some parameters
+# in a documented function, or documenting parameters that don't exist or using
+# markup commands wrongly.
+# The default value is: YES.
+
+WARN_IF_DOC_ERROR      = YES
+
+# This WARN_NO_PARAMDOC option can be enabled to get warnings for functions that
+# are documented, but have no documentation for their parameters or return
+# value. If set to NO, doxygen will only warn about wrong or incomplete
+# parameter documentation, but not about the absence of documentation.
+# The default value is: NO.
+
+WARN_NO_PARAMDOC       = NO
+
+# If the WARN_AS_ERROR tag is set to YES then doxygen will immediately stop when
+# a warning is encountered.
+# The default value is: NO.
+
+WARN_AS_ERROR          = NO
+
+# The WARN_FORMAT tag determines the format of the warning messages that doxygen
+# can produce. The string should contain the $file, $line, and $text tags, which
+# will be replaced by the file and line number from which the warning originated
+# and the warning text. Optionally the format may contain $version, which will
+# be replaced by the version of the file (if it could be obtained via
+# FILE_VERSION_FILTER)
+# The default value is: $file:$line: $text.
+
+WARN_FORMAT            = "$file:$line: $text"
+
+# The WARN_LOGFILE tag can be used to specify a file to which warning and error
+# messages should be written. If left blank the output is written to standard
+# error (stderr).
+
+WARN_LOGFILE           =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the input files
+#---------------------------------------------------------------------------
+
+# The INPUT tag is used to specify the files and/or directories that contain
+# documented source files. You may enter file names like myfile.cpp or
+# directories like /usr/src/myproject. Separate the files or directories with
+# spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
+# Note: If this tag is empty the current directory is searched.
+
+INPUT                  = README.md include src
+
+# This tag can be used to specify the character encoding of the source files
+# that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
+# libiconv (or the iconv built into libc) for the transcoding. See the libiconv
+# documentation (see: http://www.gnu.org/software/libiconv) for the list of
+# possible encodings.
+# The default value is: UTF-8.
+
+INPUT_ENCODING         = UTF-8
+
+# If the value of the INPUT tag contains directories, you can use the
+# FILE_PATTERNS tag to specify one or more wildcard patterns (like *.cpp and
+# *.h) to filter out the source-files in the directories.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# read by doxygen.
+#
+# If left blank the following patterns are tested:*.c, *.cc, *.cxx, *.cpp,
+# *.c++, *.java, *.ii, *.ixx, *.ipp, *.i++, *.inl, *.idl, *.ddl, *.odl, *.h,
+# *.hh, *.hxx, *.hpp, *.h++, *.cs, *.d, *.php, *.php4, *.php5, *.phtml, *.inc,
+# *.m, *.markdown, *.md, *.mm, *.dox, *.py, *.pyw, *.f90, *.f, *.for, *.tcl,
+# *.vhd, *.vhdl, *.ucf, *.qsf, *.as and *.js.
+
+FILE_PATTERNS          =
+
+# The RECURSIVE tag can be used to specify whether or not subdirectories should
+# be searched for input files as well.
+# The default value is: NO.
+
+RECURSIVE              = NO
+
+# The EXCLUDE tag can be used to specify files and/or directories that should be
+# excluded from the INPUT source files. This way you can easily exclude a
+# subdirectory from a directory tree whose root is specified with the INPUT tag.
+#
+# Note that relative paths are relative to the directory from which doxygen is
+# run.
+
+EXCLUDE                =
+
+# The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
+# directories that are symbolic links (a Unix file system feature) are excluded
+# from the input.
+# The default value is: NO.
+
+EXCLUDE_SYMLINKS       = NO
+
+# If the value of the INPUT tag contains directories, you can use the
+# EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
+# certain files from those directories.
+#
+# Note that the wildcards are matched against the file with absolute path, so to
+# exclude all test directories for example use the pattern */test/*
+
+EXCLUDE_PATTERNS       =
+
+# The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
+# (namespaces, classes, functions, etc.) that should be excluded from the
+# output. The symbol name can be a fully qualified name, a word, or if the
+# wildcard * is used, a substring. Examples: ANamespace, AClass,
+# AClass::ANamespace, ANamespace::*Test
+#
+# Note that the wildcards are matched against the file with absolute path, so to
+# exclude all test directories use the pattern */test/*
+
+EXCLUDE_SYMBOLS        =
+
+# The EXAMPLE_PATH tag can be used to specify one or more files or directories
+# that contain example code fragments that are included (see the \include
+# command).
+
+EXAMPLE_PATH           = examples
+
+# If the value of the EXAMPLE_PATH tag contains directories, you can use the
+# EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp and
+# *.h) to filter out the source-files in the directories. If left blank all
+# files are included.
+
+EXAMPLE_PATTERNS       =
+
+# If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
+# searched for input files to be used with the \include or \dontinclude commands
+# irrespective of the value of the RECURSIVE tag.
+# The default value is: NO.
+
+EXAMPLE_RECURSIVE      = NO
+
+# The IMAGE_PATH tag can be used to specify one or more files or directories
+# that contain images that are to be included in the documentation (see the
+# \image command).
+
+IMAGE_PATH             =
+
+# The INPUT_FILTER tag can be used to specify a program that doxygen should
+# invoke to filter for each input file. Doxygen will invoke the filter program
+# by executing (via popen()) the command:
+#
+# <filter> <input-file>
+#
+# where <filter> is the value of the INPUT_FILTER tag, and <input-file> is the
+# name of an input file. Doxygen will then use the output that the filter
+# program writes to standard output. If FILTER_PATTERNS is specified, this tag
+# will be ignored.
+#
+# Note that the filter must not add or remove lines; it is applied before the
+# code is scanned, but not when the output code is generated. If lines are added
+# or removed, the anchors will not be placed correctly.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
+
+INPUT_FILTER           =
+
+# The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
+# basis. Doxygen will compare the file name with each pattern and apply the
+# filter if there is a match. The filters are a list of the form: pattern=filter
+# (like *.cpp=my_cpp_filter). See INPUT_FILTER for further information on how
+# filters are used. If the FILTER_PATTERNS tag is empty or if none of the
+# patterns match the file name, INPUT_FILTER is applied.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
+
+FILTER_PATTERNS        =
+
+# If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
+# INPUT_FILTER) will also be used to filter the input files that are used for
+# producing the source files to browse (i.e. when SOURCE_BROWSER is set to YES).
+# The default value is: NO.
+
+FILTER_SOURCE_FILES    = NO
+
+# The FILTER_SOURCE_PATTERNS tag can be used to specify source filters per file
+# pattern. A pattern will override the setting for FILTER_PATTERN (if any) and
+# it is also possible to disable source filtering for a specific pattern using
+# *.ext= (so without naming a filter).
+# This tag requires that the tag FILTER_SOURCE_FILES is set to YES.
+
+FILTER_SOURCE_PATTERNS =
+
+# If the USE_MDFILE_AS_MAINPAGE tag refers to the name of a markdown file that
+# is part of the input, its contents will be placed on the main page
+# (index.html). This can be useful if you have a project on for instance GitHub
+# and want to reuse the introduction page also for the doxygen output.
+
+USE_MDFILE_AS_MAINPAGE = README.md
+
+#---------------------------------------------------------------------------
+# Configuration options related to source browsing
+#---------------------------------------------------------------------------
+
+# If the SOURCE_BROWSER tag is set to YES then a list of source files will be
+# generated. Documented entities will be cross-referenced with these sources.
+#
+# Note: To get rid of all source code in the generated output, make sure that
+# also VERBATIM_HEADERS is set to NO.
+# The default value is: NO.
+
+SOURCE_BROWSER         = NO
+
+# Setting the INLINE_SOURCES tag to YES will include the body of functions,
+# classes and enums directly into the documentation.
+# The default value is: NO.
+
+INLINE_SOURCES         = NO
+
+# Setting the STRIP_CODE_COMMENTS tag to YES will instruct doxygen to hide any
+# special comment blocks from generated source code fragments. Normal C, C++ and
+# Fortran comments will always remain visible.
+# The default value is: YES.
+
+STRIP_CODE_COMMENTS    = YES
+
+# If the REFERENCED_BY_RELATION tag is set to YES then for each documented
+# function all documented functions referencing it will be listed.
+# The default value is: NO.
+
+REFERENCED_BY_RELATION = NO
+
+# If the REFERENCES_RELATION tag is set to YES then for each documented function
+# all documented entities called/used by that function will be listed.
+# The default value is: NO.
+
+REFERENCES_RELATION    = NO
+
+# If the REFERENCES_LINK_SOURCE tag is set to YES and SOURCE_BROWSER tag is set
+# to YES then the hyperlinks from functions in REFERENCES_RELATION and
+# REFERENCED_BY_RELATION lists will link to the source code. Otherwise they will
+# link to the documentation.
+# The default value is: YES.
+
+REFERENCES_LINK_SOURCE = YES
+
+# If SOURCE_TOOLTIPS is enabled (the default) then hovering a hyperlink in the
+# source code will show a tooltip with additional information such as prototype,
+# brief description and links to the definition and documentation. Since this
+# will make the HTML file larger and loading of large files a bit slower, you
+# can opt to disable this feature.
+# The default value is: YES.
+# This tag requires that the tag SOURCE_BROWSER is set to YES.
+
+SOURCE_TOOLTIPS        = YES
+
+# If the USE_HTAGS tag is set to YES then the references to source code will
+# point to the HTML generated by the htags(1) tool instead of doxygen built-in
+# source browser. The htags tool is part of GNU's global source tagging system
+# (see http://www.gnu.org/software/global/global.html). You will need version
+# 4.8.6 or higher.
+#
+# To use it do the following:
+# - Install the latest version of global
+# - Enable SOURCE_BROWSER and USE_HTAGS in the config file
+# - Make sure the INPUT points to the root of the source tree
+# - Run doxygen as normal
+#
+# Doxygen will invoke htags (and that will in turn invoke gtags), so these
+# tools must be available from the command line (i.e. in the search path).
+#
+# The result: instead of the source browser generated by doxygen, the links to
+# source code will now point to the output of htags.
+# The default value is: NO.
+# This tag requires that the tag SOURCE_BROWSER is set to YES.
+
+USE_HTAGS              = NO
+
+# If the VERBATIM_HEADERS tag is set the YES then doxygen will generate a
+# verbatim copy of the header file for each class for which an include is
+# specified. Set to NO to disable this.
+# See also: Section \class.
+# The default value is: YES.
+
+VERBATIM_HEADERS       = YES
+
+# If the CLANG_ASSISTED_PARSING tag is set to YES then doxygen will use the
+# clang parser (see: http://clang.llvm.org/) for more accurate parsing at the
+# cost of reduced performance. This can be particularly helpful with template
+# rich C++ code for which doxygen's built-in parser lacks the necessary type
+# information.
+# Note: The availability of this option depends on whether or not doxygen was
+# generated with the -Duse-libclang=ON option for CMake.
+# The default value is: NO.
+
+CLANG_ASSISTED_PARSING = NO
+
+# If clang assisted parsing is enabled you can provide the compiler with command
+# line options that you would normally use when invoking the compiler. Note that
+# the include paths will already be set by doxygen for the files and directories
+# specified with INPUT and INCLUDE_PATH.
+# This tag requires that the tag CLANG_ASSISTED_PARSING is set to YES.
+
+CLANG_OPTIONS          =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the alphabetical class index
+#---------------------------------------------------------------------------
+
+# If the ALPHABETICAL_INDEX tag is set to YES, an alphabetical index of all
+# compounds will be generated. Enable this if the project contains a lot of
+# classes, structs, unions or interfaces.
+# The default value is: YES.
+
+ALPHABETICAL_INDEX     = YES
+
+# The COLS_IN_ALPHA_INDEX tag can be used to specify the number of columns in
+# which the alphabetical index list will be split.
+# Minimum value: 1, maximum value: 20, default value: 5.
+# This tag requires that the tag ALPHABETICAL_INDEX is set to YES.
+
+COLS_IN_ALPHA_INDEX    = 5
+
+# In case all classes in a project start with a common prefix, all classes will
+# be put under the same header in the alphabetical index. The IGNORE_PREFIX tag
+# can be used to specify a prefix (or a list of prefixes) that should be ignored
+# while generating the index headers.
+# This tag requires that the tag ALPHABETICAL_INDEX is set to YES.
+
+IGNORE_PREFIX          =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the HTML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_HTML tag is set to YES, doxygen will generate HTML output
+# The default value is: YES.
+
+GENERATE_HTML          = YES
+
+# The HTML_OUTPUT tag is used to specify where the HTML docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: html.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_OUTPUT            = .
+
+# The HTML_FILE_EXTENSION tag can be used to specify the file extension for each
+# generated HTML page (for example: .htm, .php, .asp).
+# The default value is: .html.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FILE_EXTENSION    = .html
+
+# The HTML_HEADER tag can be used to specify a user-defined HTML header file for
+# each generated HTML page. If the tag is left blank doxygen will generate a
+# standard header.
+#
+# To get valid HTML the header file that includes any scripts and style sheets
+# that doxygen needs, which is dependent on the configuration options used (e.g.
+# the setting GENERATE_TREEVIEW). It is highly recommended to start with a
+# default header using
+# doxygen -w html new_header.html new_footer.html new_stylesheet.css
+# YourConfigFile
+# and then modify the file new_header.html. See also section "Doxygen usage"
+# for information on how to generate the default header that doxygen normally
+# uses.
+# Note: The header is subject to change so you typically have to regenerate the
+# default header when upgrading to a newer version of doxygen. For a description
+# of the possible markers and block names see the documentation.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_HEADER            =
+
+# The HTML_FOOTER tag can be used to specify a user-defined HTML footer for each
+# generated HTML page. If the tag is left blank doxygen will generate a standard
+# footer. See HTML_HEADER for more information on how to generate a default
+# footer and what special commands can be used inside the footer. See also
+# section "Doxygen usage" for information on how to generate the default footer
+# that doxygen normally uses.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FOOTER            =
+
+# The HTML_STYLESHEET tag can be used to specify a user-defined cascading style
+# sheet that is used by each HTML page. It can be used to fine-tune the look of
+# the HTML output. If left blank doxygen will generate a default style sheet.
+# See also section "Doxygen usage" for information on how to generate the style
+# sheet that doxygen normally uses.
+# Note: It is recommended to use HTML_EXTRA_STYLESHEET instead of this tag, as
+# it is more robust and this tag (HTML_STYLESHEET) will in the future become
+# obsolete.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_STYLESHEET        =
+
+# The HTML_EXTRA_STYLESHEET tag can be used to specify additional user-defined
+# cascading style sheets that are included after the standard style sheets
+# created by doxygen. Using this option one can overrule certain style aspects.
+# This is preferred over using HTML_STYLESHEET since it does not replace the
+# standard style sheet and is therefore more robust against future updates.
+# Doxygen will copy the style sheet files to the output directory.
+# Note: The order of the extra style sheet files is of importance (e.g. the last
+# style sheet in the list overrules the setting of the previous ones in the
+# list). For an example see the documentation.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_EXTRA_STYLESHEET  =
+
+# The HTML_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the HTML output directory. Note
+# that these files will be copied to the base HTML output directory. Use the
+# $relpath^ marker in the HTML_HEADER and/or HTML_FOOTER files to load these
+# files. In the HTML_STYLESHEET file, use the file name only. Also note that the
+# files will be copied as-is; there are no commands or markers available.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_EXTRA_FILES       =
+
+# The HTML_COLORSTYLE_HUE tag controls the color of the HTML output. Doxygen
+# will adjust the colors in the style sheet and background images according to
+# this color. Hue is specified as an angle on a colorwheel, see
+# http://en.wikipedia.org/wiki/Hue for more information. For instance the value
+# 0 represents red, 60 is yellow, 120 is green, 180 is cyan, 240 is blue, 300
+# purple, and 360 is red again.
+# Minimum value: 0, maximum value: 359, default value: 220.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_HUE    = 220
+
+# The HTML_COLORSTYLE_SAT tag controls the purity (or saturation) of the colors
+# in the HTML output. For a value of 0 the output will use grayscales only. A
+# value of 255 will produce the most vivid colors.
+# Minimum value: 0, maximum value: 255, default value: 100.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_SAT    = 100
+
+# The HTML_COLORSTYLE_GAMMA tag controls the gamma correction applied to the
+# luminance component of the colors in the HTML output. Values below 100
+# gradually make the output lighter, whereas values above 100 make the output
+# darker. The value divided by 100 is the actual gamma applied, so 80 represents
+# a gamma of 0.8, The value 220 represents a gamma of 2.2, and 100 does not
+# change the gamma.
+# Minimum value: 40, maximum value: 240, default value: 80.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_GAMMA  = 80
+
+# If the HTML_TIMESTAMP tag is set to YES then the footer of each generated HTML
+# page will contain the date and time when the page was generated. Setting this
+# to YES can help to show when doxygen was last run and thus if the
+# documentation is up to date.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_TIMESTAMP         = NO
+
+# If the HTML_DYNAMIC_SECTIONS tag is set to YES then the generated HTML
+# documentation will contain sections that can be hidden and shown after the
+# page has loaded.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_DYNAMIC_SECTIONS  = NO
+
+# With HTML_INDEX_NUM_ENTRIES one can control the preferred number of entries
+# shown in the various tree structured indices initially; the user can expand
+# and collapse entries dynamically later on. Doxygen will expand the tree to
+# such a level that at most the specified number of entries are visible (unless
+# a fully collapsed tree already exceeds this amount). So setting the number of
+# entries 1 will produce a full collapsed tree by default. 0 is a special value
+# representing an infinite number of entries and will result in a full expanded
+# tree by default.
+# Minimum value: 0, maximum value: 9999, default value: 100.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_INDEX_NUM_ENTRIES = 100
+
+# If the GENERATE_DOCSET tag is set to YES, additional index files will be
+# generated that can be used as input for Apple's Xcode 3 integrated development
+# environment (see: http://developer.apple.com/tools/xcode/), introduced with
+# OSX 10.5 (Leopard). To create a documentation set, doxygen will generate a
+# Makefile in the HTML output directory. Running make will produce the docset in
+# that directory and running make install will install the docset in
+# ~/Library/Developer/Shared/Documentation/DocSets so that Xcode will find it at
+# startup. See http://developer.apple.com/tools/creatingdocsetswithdoxygen.html
+# for more information.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_DOCSET        = NO
+
+# This tag determines the name of the docset feed. A documentation feed provides
+# an umbrella under which multiple documentation sets from a single provider
+# (such as a company or product suite) can be grouped.
+# The default value is: Doxygen generated docs.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_FEEDNAME        = "Doxygen generated docs"
+
+# This tag specifies a string that should uniquely identify the documentation
+# set bundle. This should be a reverse domain-name style string, e.g.
+# com.mycompany.MyDocSet. Doxygen will append .docset to the name.
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_BUNDLE_ID       = org.doxygen.Project
+
+# The DOCSET_PUBLISHER_ID tag specifies a string that should uniquely identify
+# the documentation publisher. This should be a reverse domain-name style
+# string, e.g. com.mycompany.MyDocSet.documentation.
+# The default value is: org.doxygen.Publisher.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
+
+# The DOCSET_PUBLISHER_NAME tag identifies the documentation publisher.
+# The default value is: Publisher.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_PUBLISHER_NAME  = Publisher
+
+# If the GENERATE_HTMLHELP tag is set to YES then doxygen generates three
+# additional HTML index files: index.hhp, index.hhc, and index.hhk. The
+# index.hhp is a project file that can be read by Microsoft's HTML Help Workshop
+# (see: http://www.microsoft.com/en-us/download/details.aspx?id=21138) on
+# Windows.
+#
+# The HTML Help Workshop contains a compiler that can convert all HTML output
+# generated by doxygen into a single compiled HTML file (.chm). Compiled HTML
+# files are now used as the Windows 98 help format, and will replace the old
+# Windows help format (.hlp) on all Windows platforms in the future. Compressed
+# HTML files also contain an index, a table of contents, and you can search for
+# words in the documentation. The HTML workshop also contains a viewer for
+# compressed HTML files.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_HTMLHELP      = NO
+
+# The CHM_FILE tag can be used to specify the file name of the resulting .chm
+# file. You can add a path in front of the file if the result should not be
+# written to the html output directory.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+CHM_FILE               =
+
+# The HHC_LOCATION tag can be used to specify the location (absolute path
+# including file name) of the HTML help compiler (hhc.exe). If non-empty,
+# doxygen will try to run the HTML help compiler on the generated index.hhp.
+# The file has to be specified with full path.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+HHC_LOCATION           =
+
+# The GENERATE_CHI flag controls if a separate .chi index file is generated
+# (YES) or that it should be included in the master .chm file (NO).
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+GENERATE_CHI           = NO
+
+# The CHM_INDEX_ENCODING is used to encode HtmlHelp index (hhk), content (hhc)
+# and project file content.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+CHM_INDEX_ENCODING     =
+
+# The BINARY_TOC flag controls whether a binary table of contents is generated
+# (YES) or a normal table of contents (NO) in the .chm file. Furthermore it
+# enables the Previous and Next buttons.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+BINARY_TOC             = NO
+
+# The TOC_EXPAND flag can be set to YES to add extra items for group members to
+# the table of contents of the HTML help documentation and to the tree view.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+TOC_EXPAND             = NO
+
+# If the GENERATE_QHP tag is set to YES and both QHP_NAMESPACE and
+# QHP_VIRTUAL_FOLDER are set, an additional index file will be generated that
+# can be used as input for Qt's qhelpgenerator to generate a Qt Compressed Help
+# (.qch) of the generated HTML documentation.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_QHP           = NO
+
+# If the QHG_LOCATION tag is specified, the QCH_FILE tag can be used to specify
+# the file name of the resulting .qch file. The path specified is relative to
+# the HTML output folder.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QCH_FILE               =
+
+# The QHP_NAMESPACE tag specifies the namespace to use when generating Qt Help
+# Project output. For more information please see Qt Help Project / Namespace
+# (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#namespace).
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_NAMESPACE          = org.doxygen.Project
+
+# The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating Qt
+# Help Project output. For more information please see Qt Help Project / Virtual
+# Folders (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#virtual-
+# folders).
+# The default value is: doc.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_VIRTUAL_FOLDER     = doc
+
+# If the QHP_CUST_FILTER_NAME tag is set, it specifies the name of a custom
+# filter to add. For more information please see Qt Help Project / Custom
+# Filters (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-
+# filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_NAME   =
+
+# The QHP_CUST_FILTER_ATTRS tag specifies the list of the attributes of the
+# custom filter to add. For more information please see Qt Help Project / Custom
+# Filters (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-
+# filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_ATTRS  =
+
+# The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
+# project's filter section matches. Qt Help Project / Filter Attributes (see:
+# http://qt-project.org/doc/qt-4.8/qthelpproject.html#filter-attributes).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_SECT_FILTER_ATTRS  =
+
+# The QHG_LOCATION tag can be used to specify the location of Qt's
+# qhelpgenerator. If non-empty doxygen will try to run qhelpgenerator on the
+# generated .qhp file.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHG_LOCATION           =
+
+# If the GENERATE_ECLIPSEHELP tag is set to YES, additional index files will be
+# generated, together with the HTML files, they form an Eclipse help plugin. To
+# install this plugin and make it available under the help contents menu in
+# Eclipse, the contents of the directory containing the HTML and XML files needs
+# to be copied into the plugins directory of eclipse. The name of the directory
+# within the plugins directory should be the same as the ECLIPSE_DOC_ID value.
+# After copying Eclipse needs to be restarted before the help appears.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_ECLIPSEHELP   = NO
+
+# A unique identifier for the Eclipse help plugin. When installing the plugin
+# the directory name containing the HTML and XML files should also have this
+# name. Each documentation set should have its own identifier.
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_ECLIPSEHELP is set to YES.
+
+ECLIPSE_DOC_ID         = org.doxygen.Project
+
+# If you want full control over the layout of the generated HTML pages it might
+# be necessary to disable the index and replace it with your own. The
+# DISABLE_INDEX tag can be used to turn on/off the condensed index (tabs) at top
+# of each HTML page. A value of NO enables the index and the value YES disables
+# it. Since the tabs in the index contain the same information as the navigation
+# tree, you can set this option to YES if you also set GENERATE_TREEVIEW to YES.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+DISABLE_INDEX          = NO
+
+# The GENERATE_TREEVIEW tag is used to specify whether a tree-like index
+# structure should be generated to display hierarchical information. If the tag
+# value is set to YES, a side panel will be generated containing a tree-like
+# index structure (just like the one that is generated for HTML Help). For this
+# to work a browser that supports JavaScript, DHTML, CSS and frames is required
+# (i.e. any modern browser). Windows users are probably better off using the
+# HTML help feature. Via custom style sheets (see HTML_EXTRA_STYLESHEET) one can
+# further fine-tune the look of the index. As an example, the default style
+# sheet generated by doxygen has an example that shows how to put an image at
+# the root of the tree instead of the PROJECT_NAME. Since the tree basically has
+# the same information as the tab index, you could consider setting
+# DISABLE_INDEX to YES when enabling this option.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_TREEVIEW      = NO
+
+# The ENUM_VALUES_PER_LINE tag can be used to set the number of enum values that
+# doxygen will group on one line in the generated HTML documentation.
+#
+# Note that a value of 0 will completely suppress the enum values from appearing
+# in the overview section.
+# Minimum value: 0, maximum value: 20, default value: 4.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+ENUM_VALUES_PER_LINE   = 4
+
+# If the treeview is enabled (see GENERATE_TREEVIEW) then this tag can be used
+# to set the initial width (in pixels) of the frame in which the tree is shown.
+# Minimum value: 0, maximum value: 1500, default value: 250.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+TREEVIEW_WIDTH         = 250
+
+# If the EXT_LINKS_IN_WINDOW option is set to YES, doxygen will open links to
+# external symbols imported via tag files in a separate window.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+EXT_LINKS_IN_WINDOW    = NO
+
+# Use this tag to change the font size of LaTeX formulas included as images in
+# the HTML documentation. When you change the font size after a successful
+# doxygen run you need to manually remove any form_*.png images from the HTML
+# output directory to force them to be regenerated.
+# Minimum value: 8, maximum value: 50, default value: 10.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FORMULA_FONTSIZE       = 10
+
+# Use the FORMULA_TRANPARENT tag to determine whether or not the images
+# generated for formulas are transparent PNGs. Transparent PNGs are not
+# supported properly for IE 6.0, but are supported on all modern browsers.
+#
+# Note that when changing this option you need to delete any form_*.png files in
+# the HTML output directory before the changes have effect.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FORMULA_TRANSPARENT    = YES
+
+# Enable the USE_MATHJAX option to render LaTeX formulas using MathJax (see
+# http://www.mathjax.org) which uses client side Javascript for the rendering
+# instead of using pre-rendered bitmaps. Use this if you do not have LaTeX
+# installed or if you want to formulas look prettier in the HTML output. When
+# enabled you may also need to install MathJax separately and configure the path
+# to it using the MATHJAX_RELPATH option.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+USE_MATHJAX            = NO
+
+# When MathJax is enabled you can set the default output format to be used for
+# the MathJax output. See the MathJax site (see:
+# http://docs.mathjax.org/en/latest/output.html) for more details.
+# Possible values are: HTML-CSS (which is slower, but has the best
+# compatibility), NativeMML (i.e. MathML) and SVG.
+# The default value is: HTML-CSS.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_FORMAT         = HTML-CSS
+
+# When MathJax is enabled you need to specify the location relative to the HTML
+# output directory using the MATHJAX_RELPATH option. The destination directory
+# should contain the MathJax.js script. For instance, if the mathjax directory
+# is located at the same level as the HTML output directory, then
+# MATHJAX_RELPATH should be ../mathjax. The default value points to the MathJax
+# Content Delivery Network so you can quickly see the result without installing
+# MathJax. However, it is strongly recommended to install a local copy of
+# MathJax from http://www.mathjax.org before deployment.
+# The default value is: http://cdn.mathjax.org/mathjax/latest.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_RELPATH        = http://cdn.mathjax.org/mathjax/latest
+
+# The MATHJAX_EXTENSIONS tag can be used to specify one or more MathJax
+# extension names that should be enabled during MathJax rendering. For example
+# MATHJAX_EXTENSIONS = TeX/AMSmath TeX/AMSsymbols
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_EXTENSIONS     =
+
+# The MATHJAX_CODEFILE tag can be used to specify a file with javascript pieces
+# of code that will be used on startup of the MathJax code. See the MathJax site
+# (see: http://docs.mathjax.org/en/latest/output.html) for more details. For an
+# example see the documentation.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_CODEFILE       =
+
+# When the SEARCHENGINE tag is enabled doxygen will generate a search box for
+# the HTML output. The underlying search engine uses javascript and DHTML and
+# should work on any modern browser. Note that when using HTML help
+# (GENERATE_HTMLHELP), Qt help (GENERATE_QHP), or docsets (GENERATE_DOCSET)
+# there is already a search function so this one should typically be disabled.
+# For large projects the javascript based search engine can be slow, then
+# enabling SERVER_BASED_SEARCH may provide a better solution. It is possible to
+# search using the keyboard; to jump to the search box use <access key> + S
+# (what the <access key> is depends on the OS and browser, but it is typically
+# <CTRL>, <ALT>/<option>, or both). Inside the search box use the <cursor down
+# key> to jump into the search results window, the results can be navigated
+# using the <cursor keys>. Press <Enter> to select an item or <escape> to cancel
+# the search. The filter options can be selected when the cursor is inside the
+# search box by pressing <Shift>+<cursor down>. Also here use the <cursor keys>
+# to select a filter and <Enter> or <escape> to activate or cancel the filter
+# option.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+SEARCHENGINE           = NO
+
+# When the SERVER_BASED_SEARCH tag is enabled the search engine will be
+# implemented using a web server instead of a web client using Javascript. There
+# are two flavors of web server based searching depending on the EXTERNAL_SEARCH
+# setting. When disabled, doxygen will generate a PHP script for searching and
+# an index file used by the script. When EXTERNAL_SEARCH is enabled the indexing
+# and searching needs to be provided by external tools. See the section
+# "External Indexing and Searching" for details.
+# The default value is: NO.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SERVER_BASED_SEARCH    = NO
+
+# When EXTERNAL_SEARCH tag is enabled doxygen will no longer generate the PHP
+# script for searching. Instead the search results are written to an XML file
+# which needs to be processed by an external indexer. Doxygen will invoke an
+# external search engine pointed to by the SEARCHENGINE_URL option to obtain the
+# search results.
+#
+# Doxygen ships with an example indexer (doxyindexer) and search engine
+# (doxysearch.cgi) which are based on the open source search engine library
+# Xapian (see: http://xapian.org/).
+#
+# See the section "External Indexing and Searching" for details.
+# The default value is: NO.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTERNAL_SEARCH        = NO
+
+# The SEARCHENGINE_URL should point to a search engine hosted by a web server
+# which will return the search results when EXTERNAL_SEARCH is enabled.
+#
+# Doxygen ships with an example indexer (doxyindexer) and search engine
+# (doxysearch.cgi) which are based on the open source search engine library
+# Xapian (see: http://xapian.org/). See the section "External Indexing and
+# Searching" for details.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SEARCHENGINE_URL       =
+
+# When SERVER_BASED_SEARCH and EXTERNAL_SEARCH are both enabled the unindexed
+# search data is written to a file for indexing by an external tool. With the
+# SEARCHDATA_FILE tag the name of this file can be specified.
+# The default file is: searchdata.xml.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SEARCHDATA_FILE        = searchdata.xml
+
+# When SERVER_BASED_SEARCH and EXTERNAL_SEARCH are both enabled the
+# EXTERNAL_SEARCH_ID tag can be used as an identifier for the project. This is
+# useful in combination with EXTRA_SEARCH_MAPPINGS to search through multiple
+# projects and redirect the results back to the right project.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTERNAL_SEARCH_ID     =
+
+# The EXTRA_SEARCH_MAPPINGS tag can be used to enable searching through doxygen
+# projects other than the one defined by this configuration file, but that are
+# all added to the same external search index. Each project needs to have a
+# unique id set via EXTERNAL_SEARCH_ID. The search mapping then maps the id of
+# to a relative location where the documentation can be found. The format is:
+# EXTRA_SEARCH_MAPPINGS = tagname1=loc1 tagname2=loc2 ...
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTRA_SEARCH_MAPPINGS  =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the LaTeX output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_LATEX tag is set to YES, doxygen will generate LaTeX output.
+# The default value is: YES.
+
+GENERATE_LATEX         = NO
+
+# The LATEX_OUTPUT tag is used to specify where the LaTeX docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: latex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_OUTPUT           = latex
+
+# The LATEX_CMD_NAME tag can be used to specify the LaTeX command name to be
+# invoked.
+#
+# Note that when enabling USE_PDFLATEX this option is only used for generating
+# bitmaps for formulas in the HTML output, but not in the Makefile that is
+# written to the output directory.
+# The default file is: latex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_CMD_NAME         = latex
+
+# The MAKEINDEX_CMD_NAME tag can be used to specify the command name to generate
+# index for LaTeX.
+# The default file is: makeindex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+MAKEINDEX_CMD_NAME     = makeindex
+
+# If the COMPACT_LATEX tag is set to YES, doxygen generates more compact LaTeX
+# documents. This may be useful for small projects and may help to save some
+# trees in general.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+COMPACT_LATEX          = NO
+
+# The PAPER_TYPE tag can be used to set the paper type that is used by the
+# printer.
+# Possible values are: a4 (210 x 297 mm), letter (8.5 x 11 inches), legal (8.5 x
+# 14 inches) and executive (7.25 x 10.5 inches).
+# The default value is: a4.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+PAPER_TYPE             = a4
+
+# The EXTRA_PACKAGES tag can be used to specify one or more LaTeX package names
+# that should be included in the LaTeX output. The package can be specified just
+# by its name or with the correct syntax as to be used with the LaTeX
+# \usepackage command. To get the times font for instance you can specify :
+# EXTRA_PACKAGES=times or EXTRA_PACKAGES={times}
+# To use the option intlimits with the amsmath package you can specify:
+# EXTRA_PACKAGES=[intlimits]{amsmath}
+# If left blank no extra packages will be included.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+EXTRA_PACKAGES         =
+
+# The LATEX_HEADER tag can be used to specify a personal LaTeX header for the
+# generated LaTeX document. The header should contain everything until the first
+# chapter. If it is left blank doxygen will generate a standard header. See
+# section "Doxygen usage" for information on how to let doxygen write the
+# default header to a separate file.
+#
+# Note: Only use a user-defined header if you know what you are doing! The
+# following commands have a special meaning inside the header: $title,
+# $datetime, $date, $doxygenversion, $projectname, $projectnumber,
+# $projectbrief, $projectlogo. Doxygen will replace $title with the empty
+# string, for the replacement values of the other commands the user is referred
+# to HTML_HEADER.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_HEADER           =
+
+# The LATEX_FOOTER tag can be used to specify a personal LaTeX footer for the
+# generated LaTeX document. The footer should contain everything after the last
+# chapter. If it is left blank doxygen will generate a standard footer. See
+# LATEX_HEADER for more information on how to generate a default footer and what
+# special commands can be used inside the footer.
+#
+# Note: Only use a user-defined footer if you know what you are doing!
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_FOOTER           =
+
+# The LATEX_EXTRA_STYLESHEET tag can be used to specify additional user-defined
+# LaTeX style sheets that are included after the standard style sheets created
+# by doxygen. Using this option one can overrule certain style aspects. Doxygen
+# will copy the style sheet files to the output directory.
+# Note: The order of the extra style sheet files is of importance (e.g. the last
+# style sheet in the list overrules the setting of the previous ones in the
+# list).
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EXTRA_STYLESHEET =
+
+# The LATEX_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the LATEX_OUTPUT output
+# directory. Note that the files will be copied as-is; there are no commands or
+# markers available.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EXTRA_FILES      =
+
+# If the PDF_HYPERLINKS tag is set to YES, the LaTeX that is generated is
+# prepared for conversion to PDF (using ps2pdf or pdflatex). The PDF file will
+# contain links (just like the HTML output) instead of page references. This
+# makes the output suitable for online browsing using a PDF viewer.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+PDF_HYPERLINKS         = YES
+
+# If the USE_PDFLATEX tag is set to YES, doxygen will use pdflatex to generate
+# the PDF file directly from the LaTeX files. Set this option to YES, to get a
+# higher quality PDF documentation.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+USE_PDFLATEX           = YES
+
+# If the LATEX_BATCHMODE tag is set to YES, doxygen will add the \batchmode
+# command to the generated LaTeX files. This will instruct LaTeX to keep running
+# if errors occur, instead of asking the user for help. This option is also used
+# when generating formulas in HTML.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_BATCHMODE        = NO
+
+# If the LATEX_HIDE_INDICES tag is set to YES then doxygen will not include the
+# index chapters (such as File Index, Compound Index, etc.) in the output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_HIDE_INDICES     = NO
+
+# If the LATEX_SOURCE_CODE tag is set to YES then doxygen will include source
+# code with syntax highlighting in the LaTeX output.
+#
+# Note that which sources are shown also depends on other settings such as
+# SOURCE_BROWSER.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_SOURCE_CODE      = NO
+
+# The LATEX_BIB_STYLE tag can be used to specify the style to use for the
+# bibliography, e.g. plainnat, or ieeetr. See
+# http://en.wikipedia.org/wiki/BibTeX and \cite for more info.
+# The default value is: plain.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_BIB_STYLE        = plain
+
+# If the LATEX_TIMESTAMP tag is set to YES then the footer of each generated
+# page will contain the date and time when the page was generated. Setting this
+# to NO can help when comparing the output of multiple runs.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_TIMESTAMP        = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the RTF output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_RTF tag is set to YES, doxygen will generate RTF output. The
+# RTF output is optimized for Word 97 and may not look too pretty with other RTF
+# readers/editors.
+# The default value is: NO.
+
+GENERATE_RTF           = NO
+
+# The RTF_OUTPUT tag is used to specify where the RTF docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: rtf.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_OUTPUT             = rtf
+
+# If the COMPACT_RTF tag is set to YES, doxygen generates more compact RTF
+# documents. This may be useful for small projects and may help to save some
+# trees in general.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+COMPACT_RTF            = NO
+
+# If the RTF_HYPERLINKS tag is set to YES, the RTF that is generated will
+# contain hyperlink fields. The RTF file will contain links (just like the HTML
+# output) instead of page references. This makes the output suitable for online
+# browsing using Word or some other Word compatible readers that support those
+# fields.
+#
+# Note: WordPad (write) and others do not support links.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_HYPERLINKS         = NO
+
+# Load stylesheet definitions from file. Syntax is similar to doxygen's config
+# file, i.e. a series of assignments. You only have to provide replacements,
+# missing definitions are set to their default value.
+#
+# See also section "Doxygen usage" for information on how to generate the
+# default style sheet that doxygen normally uses.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_STYLESHEET_FILE    =
+
+# Set optional variables used in the generation of an RTF document. Syntax is
+# similar to doxygen's config file. A template extensions file can be generated
+# using doxygen -e rtf extensionFile.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_EXTENSIONS_FILE    =
+
+# If the RTF_SOURCE_CODE tag is set to YES then doxygen will include source code
+# with syntax highlighting in the RTF output.
+#
+# Note that which sources are shown also depends on other settings such as
+# SOURCE_BROWSER.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_SOURCE_CODE        = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the man page output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_MAN tag is set to YES, doxygen will generate man pages for
+# classes and files.
+# The default value is: NO.
+
+GENERATE_MAN           = NO
+
+# The MAN_OUTPUT tag is used to specify where the man pages will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it. A directory man3 will be created inside the directory specified by
+# MAN_OUTPUT.
+# The default directory is: man.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_OUTPUT             = man
+
+# The MAN_EXTENSION tag determines the extension that is added to the generated
+# man pages. In case the manual section does not start with a number, the number
+# 3 is prepended. The dot (.) at the beginning of the MAN_EXTENSION tag is
+# optional.
+# The default value is: .3.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_EXTENSION          = .3
+
+# The MAN_SUBDIR tag determines the name of the directory created within
+# MAN_OUTPUT in which the man pages are placed. If defaults to man followed by
+# MAN_EXTENSION with the initial . removed.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_SUBDIR             =
+
+# If the MAN_LINKS tag is set to YES and doxygen generates man output, then it
+# will generate one additional man file for each entity documented in the real
+# man page(s). These additional files only source the real man page, but without
+# them the man command would be unable to find the correct page.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_LINKS              = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the XML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_XML tag is set to YES, doxygen will generate an XML file that
+# captures the structure of the code including all documentation.
+# The default value is: NO.
+
+GENERATE_XML           = NO
+
+# The XML_OUTPUT tag is used to specify where the XML pages will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: xml.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_OUTPUT             = xml
+
+# If the XML_PROGRAMLISTING tag is set to YES, doxygen will dump the program
+# listings (including syntax highlighting and cross-referencing information) to
+# the XML output. Note that enabling this will significantly increase the size
+# of the XML output.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_PROGRAMLISTING     = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to the DOCBOOK output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_DOCBOOK tag is set to YES, doxygen will generate Docbook files
+# that can be used to generate PDF.
+# The default value is: NO.
+
+GENERATE_DOCBOOK       = NO
+
+# The DOCBOOK_OUTPUT tag is used to specify where the Docbook pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be put in
+# front of it.
+# The default directory is: docbook.
+# This tag requires that the tag GENERATE_DOCBOOK is set to YES.
+
+DOCBOOK_OUTPUT         = docbook
+
+# If the DOCBOOK_PROGRAMLISTING tag is set to YES, doxygen will include the
+# program listings (including syntax highlighting and cross-referencing
+# information) to the DOCBOOK output. Note that enabling this will significantly
+# increase the size of the DOCBOOK output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_DOCBOOK is set to YES.
+
+DOCBOOK_PROGRAMLISTING = NO
+
+#---------------------------------------------------------------------------
+# Configuration options for the AutoGen Definitions output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_AUTOGEN_DEF tag is set to YES, doxygen will generate an
+# AutoGen Definitions (see http://autogen.sf.net) file that captures the
+# structure of the code including all documentation. Note that this feature is
+# still experimental and incomplete at the moment.
+# The default value is: NO.
+
+GENERATE_AUTOGEN_DEF   = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the Perl module output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_PERLMOD tag is set to YES, doxygen will generate a Perl module
+# file that captures the structure of the code including all documentation.
+#
+# Note that this feature is still experimental and incomplete at the moment.
+# The default value is: NO.
+
+GENERATE_PERLMOD       = NO
+
+# If the PERLMOD_LATEX tag is set to YES, doxygen will generate the necessary
+# Makefile rules, Perl scripts and LaTeX code to be able to generate PDF and DVI
+# output from the Perl module output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_LATEX          = NO
+
+# If the PERLMOD_PRETTY tag is set to YES, the Perl module output will be nicely
+# formatted so it can be parsed by a human reader. This is useful if you want to
+# understand what is going on. On the other hand, if this tag is set to NO, the
+# size of the Perl module output will be much smaller and Perl will parse it
+# just the same.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_PRETTY         = YES
+
+# The names of the make variables in the generated doxyrules.make file are
+# prefixed with the string contained in PERLMOD_MAKEVAR_PREFIX. This is useful
+# so different doxyrules.make files included by the same Makefile don't
+# overwrite each other's variables.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_MAKEVAR_PREFIX =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the preprocessor
+#---------------------------------------------------------------------------
+
+# If the ENABLE_PREPROCESSING tag is set to YES, doxygen will evaluate all
+# C-preprocessor directives found in the sources and include files.
+# The default value is: YES.
+
+ENABLE_PREPROCESSING   = YES
+
+# If the MACRO_EXPANSION tag is set to YES, doxygen will expand all macro names
+# in the source code. If set to NO, only conditional compilation will be
+# performed. Macro expansion can be done in a controlled way by setting
+# EXPAND_ONLY_PREDEF to YES.
+# The default value is: NO.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+MACRO_EXPANSION        = YES
+
+# If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES then
+# the macro expansion is limited to the macros specified with the PREDEFINED and
+# EXPAND_AS_DEFINED tags.
+# The default value is: NO.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+EXPAND_ONLY_PREDEF     = NO
+
+# If the SEARCH_INCLUDES tag is set to YES, the include files in the
+# INCLUDE_PATH will be searched if a #include is found.
+# The default value is: YES.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+SEARCH_INCLUDES        = YES
+
+# The INCLUDE_PATH tag can be used to specify one or more directories that
+# contain include files that are not input files but should be processed by the
+# preprocessor.
+# This tag requires that the tag SEARCH_INCLUDES is set to YES.
+
+INCLUDE_PATH           =
+
+# You can use the INCLUDE_FILE_PATTERNS tag to specify one or more wildcard
+# patterns (like *.h and *.hpp) to filter out the header-files in the
+# directories. If left blank, the patterns specified with FILE_PATTERNS will be
+# used.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+INCLUDE_FILE_PATTERNS  =
+
+# The PREDEFINED tag can be used to specify one or more macro names that are
+# defined before the preprocessor is started (similar to the -D option of e.g.
+# gcc). The argument of the tag is a list of macros of the form: name or
+# name=definition (no spaces). If the definition and the "=" are omitted, "=1"
+# is assumed. To prevent a macro definition from being undefined via #undef or
+# recursively expanded use the := operator instead of the = operator.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+PREDEFINED             =
+
+# If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
+# tag can be used to specify a list of macro names that should be expanded. The
+# macro definition that is found in the sources will be used. Use the PREDEFINED
+# tag if you want to use a different macro definition that overrules the
+# definition found in the source code.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+EXPAND_AS_DEFINED      =
+
+# If the SKIP_FUNCTION_MACROS tag is set to YES then doxygen's preprocessor will
+# remove all references to function-like macros that are alone on a line, have
+# an all uppercase name, and do not end with a semicolon. Such function macros
+# are typically used for boiler-plate code, and will confuse the parser if not
+# removed.
+# The default value is: YES.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+SKIP_FUNCTION_MACROS   = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to external references
+#---------------------------------------------------------------------------
+
+# The TAGFILES tag can be used to specify one or more tag files. For each tag
+# file the location of the external documentation should be added. The format of
+# a tag file without this location is as follows:
+# TAGFILES = file1 file2 ...
+# Adding location for the tag files is done as follows:
+# TAGFILES = file1=loc1 "file2 = loc2" ...
+# where loc1 and loc2 can be relative or absolute paths or URLs. See the
+# section "Linking to external documentation" for more information about the use
+# of tag files.
+# Note: Each tag file must have a unique name (where the name does NOT include
+# the path). If a tag file is not located in the directory in which doxygen is
+# run, you must also specify the path to the tagfile here.
+
+TAGFILES               =
+
+# When a file name is specified after GENERATE_TAGFILE, doxygen will create a
+# tag file that is based on the input files it reads. See section "Linking to
+# external documentation" for more information about the usage of tag files.
+
+GENERATE_TAGFILE       =
+
+# If the ALLEXTERNALS tag is set to YES, all external class will be listed in
+# the class index. If set to NO, only the inherited external classes will be
+# listed.
+# The default value is: NO.
+
+ALLEXTERNALS           = NO
+
+# If the EXTERNAL_GROUPS tag is set to YES, all external groups will be listed
+# in the modules index. If set to NO, only the current project's groups will be
+# listed.
+# The default value is: YES.
+
+EXTERNAL_GROUPS        = YES
+
+# If the EXTERNAL_PAGES tag is set to YES, all external pages will be listed in
+# the related pages index. If set to NO, only the current project's pages will
+# be listed.
+# The default value is: YES.
+
+EXTERNAL_PAGES         = YES
+
+# The PERL_PATH should be the absolute path and name of the perl script
+# interpreter (i.e. the result of 'which perl').
+# The default file (with absolute path) is: /usr/bin/perl.
+
+PERL_PATH              = /usr/bin/perl
+
+#---------------------------------------------------------------------------
+# Configuration options related to the dot tool
+#---------------------------------------------------------------------------
+
+# If the CLASS_DIAGRAMS tag is set to YES, doxygen will generate a class diagram
+# (in HTML and LaTeX) for classes with base or super classes. Setting the tag to
+# NO turns the diagrams off. Note that this option also works with HAVE_DOT
+# disabled, but it is recommended to install and use dot, since it yields more
+# powerful graphs.
+# The default value is: YES.
+
+CLASS_DIAGRAMS         = YES
+
+# You can define message sequence charts within doxygen comments using the \msc
+# command. Doxygen will then run the mscgen tool (see:
+# http://www.mcternan.me.uk/mscgen/)) to produce the chart and insert it in the
+# documentation. The MSCGEN_PATH tag allows you to specify the directory where
+# the mscgen tool resides. If left empty the tool is assumed to be found in the
+# default search path.
+
+MSCGEN_PATH            =
+
+# You can include diagrams made with dia in doxygen documentation. Doxygen will
+# then run dia to produce the diagram and insert it in the documentation. The
+# DIA_PATH tag allows you to specify the directory where the dia binary resides.
+# If left empty dia is assumed to be found in the default search path.
+
+DIA_PATH               =
+
+# If set to YES the inheritance and collaboration graphs will hide inheritance
+# and usage relations if the target is undocumented or is not a class.
+# The default value is: YES.
+
+HIDE_UNDOC_RELATIONS   = YES
+
+# If you set the HAVE_DOT tag to YES then doxygen will assume the dot tool is
+# available from the path. This tool is part of Graphviz (see:
+# http://www.graphviz.org/), a graph visualization toolkit from AT&T and Lucent
+# Bell Labs. The other options in this section have no effect if this option is
+# set to NO
+# The default value is: YES.
+
+HAVE_DOT               = YES
+
+# The DOT_NUM_THREADS specifies the number of dot invocations doxygen is allowed
+# to run in parallel. When set to 0 doxygen will base this on the number of
+# processors available in the system. You can set it explicitly to a value
+# larger than 0 to get control over the balance between CPU load and processing
+# speed.
+# Minimum value: 0, maximum value: 32, default value: 0.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_NUM_THREADS        = 0
+
+# When you want a differently looking font in the dot files that doxygen
+# generates you can specify the font name using DOT_FONTNAME. You need to make
+# sure dot is able to find the font, which can be done by putting it in a
+# standard location or by setting the DOTFONTPATH environment variable or by
+# setting DOT_FONTPATH to the directory containing the font.
+# The default value is: Helvetica.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTNAME           = Helvetica
+
+# The DOT_FONTSIZE tag can be used to set the size (in points) of the font of
+# dot graphs.
+# Minimum value: 4, maximum value: 24, default value: 10.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTSIZE           = 10
+
+# By default doxygen will tell dot to use the default font as specified with
+# DOT_FONTNAME. If you specify a different font using DOT_FONTNAME you can set
+# the path where dot can find it using this tag.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTPATH           =
+
+# If the CLASS_GRAPH tag is set to YES then doxygen will generate a graph for
+# each documented class showing the direct and indirect inheritance relations.
+# Setting this tag to YES will force the CLASS_DIAGRAMS tag to NO.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+CLASS_GRAPH            = YES
+
+# If the COLLABORATION_GRAPH tag is set to YES then doxygen will generate a
+# graph for each documented class showing the direct and indirect implementation
+# dependencies (inheritance, containment, and class references variables) of the
+# class with other documented classes.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+COLLABORATION_GRAPH    = NO
+
+# If the GROUP_GRAPHS tag is set to YES then doxygen will generate a graph for
+# groups, showing the direct groups dependencies.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GROUP_GRAPHS           = YES
+
+# If the UML_LOOK tag is set to YES, doxygen will generate inheritance and
+# collaboration diagrams in a style similar to the OMG's Unified Modeling
+# Language.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+UML_LOOK               = NO
+
+# If the UML_LOOK tag is enabled, the fields and methods are shown inside the
+# class node. If there are many fields or methods and many nodes the graph may
+# become too big to be useful. The UML_LIMIT_NUM_FIELDS threshold limits the
+# number of items for each type to make the size more manageable. Set this to 0
+# for no limit. Note that the threshold may be exceeded by 50% before the limit
+# is enforced. So when you set the threshold to 10, up to 15 fields may appear,
+# but if the number exceeds 15, the total amount of fields shown is limited to
+# 10.
+# Minimum value: 0, maximum value: 100, default value: 10.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+UML_LIMIT_NUM_FIELDS   = 10
+
+# If the TEMPLATE_RELATIONS tag is set to YES then the inheritance and
+# collaboration graphs will show the relations between templates and their
+# instances.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+TEMPLATE_RELATIONS     = NO
+
+# If the INCLUDE_GRAPH, ENABLE_PREPROCESSING and SEARCH_INCLUDES tags are set to
+# YES then doxygen will generate a graph for each documented file showing the
+# direct and indirect include dependencies of the file with other documented
+# files.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INCLUDE_GRAPH          = YES
+
+# If the INCLUDED_BY_GRAPH, ENABLE_PREPROCESSING and SEARCH_INCLUDES tags are
+# set to YES then doxygen will generate a graph for each documented file showing
+# the direct and indirect include dependencies of the file with other documented
+# files.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INCLUDED_BY_GRAPH      = YES
+
+# If the CALL_GRAPH tag is set to YES then doxygen will generate a call
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+# Note: For IE 9+ you need to set HTML_FILE_EXTENSION to xhtml in order to make
+# the SVG files visible. Older versions of IE do not have SVG support.
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+
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+# by representing a node as a red box. Note that doxygen if the number of direct
+# children of the root node in a graph is already larger than
+# DOT_GRAPH_MAX_NODES then the graph will not be shown at all. Also note that
+# the size of a graph can be further restricted by MAX_DOT_GRAPH_DEPTH.
+# Minimum value: 0, maximum value: 10000, default value: 50.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_GRAPH_MAX_NODES    = 50
+
+# The MAX_DOT_GRAPH_DEPTH tag can be used to set the maximum depth of the graphs
+# generated by dot. A depth value of 3 means that only nodes reachable from the
+# root by following a path via at most 3 edges will be shown. Nodes that lay
+# further from the root node will be omitted. Note that setting this option to 1
+# or 2 may greatly reduce the computation time needed for large code bases. Also
+# note that the size of a graph can be further restricted by
+# DOT_GRAPH_MAX_NODES. Using a depth of 0 means no depth restriction.
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+
+MAX_DOT_GRAPH_DEPTH    = 0
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+# badly anti-aliased labels on the edges of a graph (i.e. they become hard to
+# read).
+# The default value is: NO.
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+
+DOT_TRANSPARENT        = NO
+
+# Set the DOT_MULTI_TARGETS tag to YES to allow dot to generate multiple output
+# files in one run (i.e. multiple -o and -T options on the command line). This
+# makes dot run faster, but since only newer versions of dot (>1.8.10) support
+# this, this feature is disabled by default.
+# The default value is: NO.
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+
+DOT_MULTI_TARGETS      = NO
+
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+# explaining the meaning of the various boxes and arrows in the dot generated
+# graphs.
+# The default value is: YES.
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+GENERATE_LEGEND        = YES
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+DOT_CLEANUP            = YES

deps/MQTT-C/LICENSE

+MIT License
+
+Copyright (c) 2018 Liam Bindle
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

deps/MQTT-C/README.md

+<p align="right">
+    <a href="https://github.com/LiamBindle/MQTT-C/stargazers"><img src="https://img.shields.io/github/stars/LiamBindle/MQTT-C.svg?style=social&label=Star" style="margin-left:5em"></a>
+    <a href="https://github.com/LiamBindle/MQTT-C/network/members"><img src="https://img.shields.io/github/forks/LiamBindle/MQTT-C.svg?style=social&label=Fork"></a>
+</p>
+
+<p align="center">
+    <img width="70%" src="docs/mqtt-c-logo.png"><br>
+    <a href="https://liambindle.ca/MQTT-C"><img src="https://img.shields.io/badge/docs-passing-brightgreen.svg"></a>
+    <a href="https://github.com/LiamBindle/MQTT-C/issues"><img src="https://img.shields.io/badge/Maintained%3F-yes-green.svg"></a>
+    <a href="https://GitHub.com/LiamBindle/MQTT-C/issues/"><img src="https://img.shields.io/github/issues/LiamBindle/MQTT-C.svg"></a>
+    <a href="https://github.com/LiamBindle/MQTT-C/issues"><img src="https://img.shields.io/github/issues-closed/LiamBindle/MQTT-C.svg"></a>
+    <a href="https://github.com/LiamBindle/MQTT-C/blob/master/LICENSE"><img src="https://img.shields.io/badge/License-MIT-blue.svg"></a>
+</p>
+
+# 
+
+MQTT-C is an [MQTT v3.1.1](http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html) 
+client written in C. MQTT is a lightweight publisher-subscriber-based messaging protocol that is
+commonly used in IoT and networking applications where high-latency and low data-rate links 
+are expected. The purpose of MQTT-C is to provide a **portable** MQTT client, **written in C**, 
+for embedded systems and PC's alike. MQTT-C does this by providing a transparent Platform 
+Abstraction Layer (PAL) which makes porting to new platforms easy. MQTT-C is completely 
+thread-safe but can also run perfectly fine on single-threaded systems making MQTT-C 
+well-suited for embedded systems and microcontrollers. Finally, MQTT-C is small; there are only 
+two source files totalling less than 2000 lines.
+
+#### A note from the author
+It's been great to hear about all the places MQTT-C is being used! Please don't hesitate
+to get in touch with me or submit issues on GitHub!
+
+## Getting Started
+To use MQTT-C you first instantiate a `struct mqtt_client` and initialize it by calling
+@ref mqtt_init.
+```c
+    struct mqtt_client client; /* instantiate the client */
+    mqtt_init(&client, ...);   /* initialize the client */
+```
+Once your client is initialized you need to connect to an MQTT broker.
+```c
+    mqtt_connect(&client, ...); /* send a connection request to the broker. */
+```
+At this point the client is ready to use! For example, we can subscribe to a topic like so:
+```c
+    /* subscribe to "toaster/temperature" with a max QoS level of 0 */
+    mqtt_subscribe(&client, "toaster/temperature", 0);
+```
+And we can publish to a topic like so:
+```c
+    /* publish coffee temperature with a QoS level of 1 */
+    int temperature = 67;
+    mqtt_publish(&client, "coffee/temperature", &temperature, sizeof(int), MQTT_PUBLISH_QOS_1);
+```
+Those are the basics! From here the [examples](https://github.com/LiamBindle/MQTT-C/tree/master/examples) and [API documentation](https://liambindle.ca/MQTT-C/group__api.html) are good places to get started.
+
+## Building
+There are **only two source files** that need to be built, `mqtt.c` and `mqtt_pal.c`.
+These files are ANSI C (C89) compatible, and should compile with any C compiler.
+
+Then, simply <code>\#include <mqtt.h></code>.
+
+Alternatively, you can build MQTT-C with CMake or the provided Makefile. These are provided for convenience.
+
+## Documentation
+Pre-built documentation can be found here: [https://liambindle.ca/MQTT-C](https://liambindle.ca/MQTT-C). Be sure to check out the [examples](https://github.com/LiamBindle/MQTT-C/tree/master/examples) too.
+
+The @ref api documentation contains all the documentation application programmers should need. 
+The @ref pal documentation contains everything you should need to port MQTT-C to a new platform,
+and the other modules contain documentation for MQTT-C developers.
+
+## Testing and Building the Tests
+The MQTT-C unit tests use the [cmocka unit testing framework](https://cmocka.org/). 
+Therefore, [cmocka](https://cmocka.org/) *must* be installed on your machine to build and run 
+the unit tests. For convenience, a simple `"makefile"` is included to build the unit tests and 
+examples on UNIX-like machines. The unit tests and examples can be built as follows:
+```bash
+    $ make all
+``` 
+The unit tests and examples will be built in the `"bin/"` directory. The unit tests can be run 
+like so:
+```bash
+    $ ./bin/tests [address [port]]
+```
+Note that the \c address and \c port arguments are both optional to specify the location of the
+MQTT broker that is to be used for the tests. If no \c address is given then the 
+[Mosquitto MQTT Test Server](https://test.mosquitto.org/) will be used. If no \c port is given, 
+port 1883 will be used.
+
+## Portability
+MQTT-C provides a transparent platform abstraction layer (PAL) in `mqtt_pal.h` and `mqtt_pal.c`.
+These files declare and implement the types and calls that MQTT-C requires. Refer to 
+@ref pal for the complete documentation of the PAL.
+
+## Contributing
+Please feel free to submit issues and pull-requests [here](https://github.com/LiamBindle/MQTT-C).
+When submitting a pull-request please ensure you have *fully documented* your changes and 
+added the appropriate unit tests.
+
+
+## License
+This project is licensed under the [MIT License](https://opensource.org/licenses/MIT). See the 
+`"LICENSE"` file for more details.
+
+## Authors
+MQTT-C was initially developed as a CMPT 434 (Winter Term, 2018) final project at the University of 
+Saskatchewan by:
+- **Liam Bindle**
+- **Demilade Adeoye**
+

deps/MQTT-C/examples/bio_publisher.c

+
+/**
+ * @file
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mqtt.h>
+#include "templates/bio_sockets.h"
+
+
+/**
+ * @brief The function that would be called whenever a PUBLISH is received.
+ * 
+ * @note This function is not used in this example. 
+ */
+void publish_callback(void** unused, struct mqtt_response_publish *published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to 
+ *        handle ingress/egress traffic to the broker.
+ * 
+ * @note All this function needs to do is call \ref __mqtt_recv and 
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that 
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* client_refresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit. 
+ */
+void exit_example(int status, BIO* sockfd, pthread_t *client_daemon);
+
+/**
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ */
+int main(int argc, const char *argv[]) 
+{
+    const char* addr;
+    const char* port;
+    const char* topic;
+
+    /* Load OpenSSL */
+    SSL_load_error_strings();
+    ERR_load_BIO_strings();
+    OpenSSL_add_all_algorithms();
+
+    /* get address (argv[1] if present) */
+    if (argc > 1) {
+        addr = argv[1];
+    } else {
+        addr = "test.mosquitto.org";
+    }
+
+    /* get port number (argv[2] if present) */
+    if (argc > 2) {
+        port = argv[2];
+    } else {
+        port = "1883";
+    }
+
+    /* get the topic name to publish */
+    if (argc > 3) {
+        topic = argv[3];
+    } else {
+        topic = "datetime";
+    }
+
+    /* open the non-blocking TCP socket (connecting to the broker) */
+    BIO* sockfd = open_nb_socket(addr, port);
+
+    if (sockfd == NULL) {
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* setup a client */
+    struct mqtt_client client;
+    uint8_t sendbuf[2048]; /* sendbuf should be large enough to hold multiple whole mqtt messages */
+    uint8_t recvbuf[1024]; /* recvbuf should be large enough any whole mqtt message expected to be received */
+    mqtt_init(&client, sockfd, sendbuf, sizeof(sendbuf), recvbuf, sizeof(recvbuf), publish_callback);
+    mqtt_connect(&client, "publishing_client", NULL, NULL, 0, NULL, NULL, 0, 400);
+
+    /* check that we don't have any errors */
+    if (client.error != MQTT_OK) {
+        fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* start a thread to refresh the client (handle egress and ingree client traffic) */
+    pthread_t client_daemon;
+    if(pthread_create(&client_daemon, NULL, client_refresher, &client)) {
+        fprintf(stderr, "Failed to start client daemon.\n");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+
+    }
+
+    /* start publishing the time */
+    printf("%s is ready to begin publishing the time.\n", argv[0]);
+    printf("Press ENTER to publish the current time.\n");
+    printf("Press CTRL-D (or any other key) to exit.\n\n");
+    while(fgetc(stdin) == '\n') {
+        /* get the current time */
+        time_t timer;
+        time(&timer);
+        struct tm* tm_info = localtime(&timer);
+        char timebuf[26];
+        strftime(timebuf, 26, "%Y-%m-%d %H:%M:%S", tm_info);
+
+        /* print a message */
+        char application_message[256];
+        snprintf(application_message, sizeof(application_message), "The time is %s", timebuf);
+        printf("%s published : \"%s\"", argv[0], application_message);
+
+        /* publish the time */
+        mqtt_publish(&client, topic, application_message, strlen(application_message) + 1, MQTT_PUBLISH_QOS_2);
+
+        /* check for errors */
+        if (client.error != MQTT_OK) {
+            fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+            exit_example(EXIT_FAILURE, sockfd, &client_daemon);
+        }
+    }   
+
+    /* disconnect */
+    printf("\n%s disconnecting from %s\n", argv[0], addr);
+    sleep(1);
+
+    /* exit */ 
+    exit_example(EXIT_SUCCESS, sockfd, &client_daemon);
+}
+
+void exit_example(int status, BIO* sockfd, pthread_t *client_daemon)
+{
+    if (sockfd != NULL) BIO_free_all(sockfd);
+    if (client_daemon != NULL) pthread_cancel(*client_daemon);
+    exit(status);
+}
+
+
+
+void publish_callback(void** unused, struct mqtt_response_publish *published) 
+{
+    /* not used in this example */
+}
+
+void* client_refresher(void* client)
+{
+    while(1) 
+    {
+        mqtt_sync((struct mqtt_client*) client);
+        usleep(100000U);
+    }
+    return NULL;
+}
\ No newline at end of file

deps/MQTT-C/examples/mbedtls_publisher.c

+
+/**
+ * @file
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mqtt.h>
+#include "templates/mbedtls_sockets.h"
+
+
+/**
+ * @brief The function that would be called whenever a PUBLISH is received.
+ * 
+ * @note This function is not used in this example. 
+ */
+void publish_callback(void** unused, struct mqtt_response_publish *published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to 
+ *        handle ingress/egress traffic to the broker.
+ * 
+ * @note All this function needs to do is call \ref __mqtt_recv and 
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that 
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* client_refresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit. 
+ */
+void exit_example(int status, mqtt_pal_socket_handle sockfd, pthread_t *client_daemon);
+
+/**
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ */
+int main(int argc, const char *argv[]) 
+{
+    const char* addr;
+    const char* port;
+    const char* topic;
+    const char* ca_file;
+
+    struct mbedtls_context ctx;
+    mqtt_pal_socket_handle sockfd;
+
+    if (argc > 1) {
+        ca_file = argv[1];
+    } else {
+        printf("error: path to the CA certificate to use\n");
+        exit(1);
+    }
+
+    /* get address (argv[2] if present) */
+    if (argc > 2) {
+        addr = argv[2];
+    } else {
+        addr = "test.mosquitto.org";
+    }
+
+    /* get port number (argv[3] if present) */
+    if (argc > 3) {
+        port = argv[3];
+    } else {
+        port = "8883";
+    }
+
+    /* get the topic name to publish */
+    if (argc > 4) {
+        topic = argv[4];
+    } else {
+        topic = "datetime";
+    }
+
+    /* open the non-blocking TCP socket (connecting to the broker) */
+    open_nb_socket(&ctx, addr, port, ca_file);
+    sockfd = &ctx.ssl_ctx;
+
+    if (sockfd == NULL) {
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* setup a client */
+    struct mqtt_client client;
+    uint8_t sendbuf[2048]; /* sendbuf should be large enough to hold multiple whole mqtt messages */
+    uint8_t recvbuf[1024]; /* recvbuf should be large enough any whole mqtt message expected to be received */
+    mqtt_init(&client, sockfd, sendbuf, sizeof(sendbuf), recvbuf, sizeof(recvbuf), publish_callback);
+    mqtt_connect(&client, "publishing_client", NULL, NULL, 0, NULL, NULL, 0, 400);
+
+    /* check that we don't have any errors */
+    if (client.error != MQTT_OK) {
+        fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* start a thread to refresh the client (handle egress and ingree client traffic) */
+    pthread_t client_daemon;
+    if(pthread_create(&client_daemon, NULL, client_refresher, &client)) {
+        fprintf(stderr, "Failed to start client daemon.\n");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+
+    }
+
+    /* start publishing the time */
+    printf("%s is ready to begin publishing the time.\n", argv[0]);
+    printf("Press ENTER to publish the current time.\n");
+    printf("Press CTRL-D (or any other key) to exit.\n\n");
+    while(fgetc(stdin) == '\n') {
+        /* get the current time */
+        time_t timer;
+        time(&timer);
+        struct tm* tm_info = localtime(&timer);
+        char timebuf[26];
+        strftime(timebuf, 26, "%Y-%m-%d %H:%M:%S", tm_info);
+
+        /* print a message */
+        char application_message[256];
+        snprintf(application_message, sizeof(application_message), "The time is %s", timebuf);
+        printf("%s published : \"%s\"", argv[0], application_message);
+
+        /* publish the time */
+        mqtt_publish(&client, topic, application_message, strlen(application_message) + 1, MQTT_PUBLISH_QOS_2);
+
+        /* check for errors */
+        if (client.error != MQTT_OK) {
+            fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+            exit_example(EXIT_FAILURE, sockfd, &client_daemon);
+        }
+    }   
+
+    /* disconnect */
+    printf("\n%s disconnecting from %s\n", argv[0], addr);
+    sleep(1);
+
+    /* exit */ 
+    exit_example(EXIT_SUCCESS, sockfd, &client_daemon);
+}
+
+void exit_example(int status, mqtt_pal_socket_handle sockfd, pthread_t *client_daemon)
+{
+    if (client_daemon != NULL) pthread_cancel(*client_daemon);
+    mbedtls_ssl_free(sockfd);
+    /* XXX free the rest of contexts */
+    exit(status);
+}
+
+
+
+void publish_callback(void** unused, struct mqtt_response_publish *published) 
+{
+    /* not used in this example */
+}
+
+void* client_refresher(void* client)
+{
+    while(1) 
+    {
+        mqtt_sync((struct mqtt_client*) client);
+        usleep(100000U);
+    }
+    return NULL;
+}

deps/MQTT-C/examples/openssl_publisher.c

+
+/**
+ * @file
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mqtt.h>
+#include "templates/openssl_sockets.h"
+
+
+/**
+ * @brief The function that would be called whenever a PUBLISH is received.
+ * 
+ * @note This function is not used in this example. 
+ */
+void publish_callback(void** unused, struct mqtt_response_publish *published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to 
+ *        handle ingress/egress traffic to the broker.
+ * 
+ * @note All this function needs to do is call \ref __mqtt_recv and 
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that 
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* client_refresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit. 
+ */
+void exit_example(int status, BIO* sockfd, pthread_t *client_daemon);
+
+/**
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ */
+int main(int argc, const char *argv[]) 
+{
+    const char* addr;
+    const char* port;
+    const char* topic;
+    const char* ca_file;
+
+    /* Load OpenSSL */
+    SSL_load_error_strings();
+    ERR_load_BIO_strings();
+    OpenSSL_add_all_algorithms();
+    SSL_library_init();
+
+    SSL_CTX* ssl_ctx;
+    BIO* sockfd;
+
+    if (argc > 1) {
+        ca_file = argv[1];
+    } else {
+        printf("error: path to the CA certificate to use\n");
+        exit(1);
+    }
+
+    /* get address (argv[2] if present) */
+    if (argc > 2) {
+        addr = argv[2];
+    } else {
+        addr = "test.mosquitto.org";
+    }
+
+    /* get port number (argv[3] if present) */
+    if (argc > 3) {
+        port = argv[3];
+    } else {
+        port = "8883";
+    }
+
+    /* get the topic name to publish */
+    if (argc > 4) {
+        topic = argv[4];
+    } else {
+        topic = "datetime";
+    }
+
+    /* open the non-blocking TCP socket (connecting to the broker) */
+    open_nb_socket(&sockfd, &ssl_ctx, addr, port, ca_file, NULL);
+
+    if (sockfd == NULL) {
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* setup a client */
+    struct mqtt_client client;
+    uint8_t sendbuf[2048]; /* sendbuf should be large enough to hold multiple whole mqtt messages */
+    uint8_t recvbuf[1024]; /* recvbuf should be large enough any whole mqtt message expected to be received */
+    mqtt_init(&client, sockfd, sendbuf, sizeof(sendbuf), recvbuf, sizeof(recvbuf), publish_callback);
+    mqtt_connect(&client, "publishing_client", NULL, NULL, 0, NULL, NULL, 0, 400);
+
+    /* check that we don't have any errors */
+    if (client.error != MQTT_OK) {
+        fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* start a thread to refresh the client (handle egress and ingree client traffic) */
+    pthread_t client_daemon;
+    if(pthread_create(&client_daemon, NULL, client_refresher, &client)) {
+        fprintf(stderr, "Failed to start client daemon.\n");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+
+    }
+
+    /* start publishing the time */
+    printf("%s is ready to begin publishing the time.\n", argv[0]);
+    printf("Press ENTER to publish the current time.\n");
+    printf("Press CTRL-D (or any other key) to exit.\n\n");
+    while(fgetc(stdin) == '\n') {
+        /* get the current time */
+        time_t timer;
+        time(&timer);
+        struct tm* tm_info = localtime(&timer);
+        char timebuf[26];
+        strftime(timebuf, 26, "%Y-%m-%d %H:%M:%S", tm_info);
+
+        /* print a message */
+        char application_message[256];
+        snprintf(application_message, sizeof(application_message), "The time is %s", timebuf);
+        printf("%s published : \"%s\"", argv[0], application_message);
+
+        /* publish the time */
+        mqtt_publish(&client, topic, application_message, strlen(application_message) + 1, MQTT_PUBLISH_QOS_2);
+
+        /* check for errors */
+        if (client.error != MQTT_OK) {
+            fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+            exit_example(EXIT_FAILURE, sockfd, &client_daemon);
+        }
+    }   
+
+    /* disconnect */
+    printf("\n%s disconnecting from %s\n", argv[0], addr);
+    sleep(1);
+
+    /* exit */ 
+    exit_example(EXIT_SUCCESS, sockfd, &client_daemon);
+}
+
+void exit_example(int status, BIO* sockfd, pthread_t *client_daemon)
+{
+    if (sockfd != NULL) BIO_free_all(sockfd);
+    if (client_daemon != NULL) pthread_cancel(*client_daemon);
+    exit(status);
+}
+
+
+
+void publish_callback(void** unused, struct mqtt_response_publish *published) 
+{
+    /* not used in this example */
+}
+
+void* client_refresher(void* client)
+{
+    while(1) 
+    {
+        mqtt_sync((struct mqtt_client*) client);
+        usleep(100000U);
+    }
+    return NULL;
+}
\ No newline at end of file

deps/MQTT-C/examples/reconnect_subscriber.c

+
+/**
+ * @file
+ * A simple subscriber program that performs automatic reconnections.
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mqtt.h>
+#include "templates/posix_sockets.h"
+
+/**
+ * @brief A structure that I will use to keep track of some data needed 
+ *        to setup the connection to the broker.
+ * 
+ * An instance of this struct will be created in my \c main(). Then, whenever
+ * \ref reconnect_client is called, this instance will be passed. 
+ */
+struct reconnect_state_t {
+    const char* hostname;
+    const char* port;
+    const char* topic;
+    uint8_t* sendbuf;
+    size_t sendbufsz;
+    uint8_t* recvbuf;
+    size_t recvbufsz;
+};
+
+
+/**
+ * @brief My reconnect callback. It will reestablish the connection whenever 
+ *        an error occurs. 
+ */
+void reconnect_client(struct mqtt_client* client, void **reconnect_state_vptr);
+
+/**
+ * @brief The function will be called whenever a PUBLISH message is received.
+ */
+void publish_callback(void** unused, struct mqtt_response_publish *published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to 
+ *        handle ingress/egress traffic to the broker.
+ * 
+ * @note All this function needs to do is call \ref __mqtt_recv and 
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that 
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* client_refresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit. 
+ */
+void exit_example(int status, int sockfd, pthread_t *client_daemon);
+
+
+int main(int argc, const char *argv[]) 
+{
+    const char* addr;
+    const char* port;
+    const char* topic;
+
+    /* get address (argv[1] if present) */
+    if (argc > 1) {
+        addr = argv[1];
+    } else {
+        addr = "test.mosquitto.org";
+    }
+
+    /* get port number (argv[2] if present) */
+    if (argc > 2) {
+        port = argv[2];
+    } else {
+        port = "1883";
+    }
+
+    /* get the topic name to publish */
+    if (argc > 3) {
+        topic = argv[3];
+    } else {
+        topic = "datetime";
+    }
+
+    /* build the reconnect_state structure which will be passed to reconnect */
+    struct reconnect_state_t reconnect_state;
+    reconnect_state.hostname = addr;
+    reconnect_state.port = port;
+    reconnect_state.topic = topic;
+    uint8_t sendbuf[2048];
+    uint8_t recvbuf[1024];
+    reconnect_state.sendbuf = sendbuf;
+    reconnect_state.sendbufsz = sizeof(sendbuf);
+    reconnect_state.recvbuf = recvbuf;
+    reconnect_state.recvbufsz = sizeof(recvbuf);
+
+    /* setup a client */
+    struct mqtt_client client;
+
+    mqtt_init_reconnect(&client, 
+                        reconnect_client, &reconnect_state, 
+                        publish_callback
+    );
+
+    /* start a thread to refresh the client (handle egress and ingree client traffic) */
+    pthread_t client_daemon;
+    if(pthread_create(&client_daemon, NULL, client_refresher, &client)) {
+        fprintf(stderr, "Failed to start client daemon.\n");
+        exit_example(EXIT_FAILURE, -1, NULL);
+
+    }
+
+    /* start publishing the time */
+    printf("%s listening for '%s' messages.\n", argv[0], topic);
+    printf("Press ENTER to inject an error.\n");
+    printf("Press CTRL-D to exit.\n\n");
+    
+    /* block */
+    while(fgetc(stdin) != EOF) {
+        printf("Injecting error: \"MQTT_ERROR_SOCKET_ERROR\"\n");
+        client.error = MQTT_ERROR_SOCKET_ERROR;
+    } 
+    
+    /* disconnect */
+    printf("\n%s disconnecting from %s\n", argv[0], addr);
+    sleep(1);
+
+    /* exit */ 
+    exit_example(EXIT_SUCCESS, client.socketfd, &client_daemon);
+}
+
+void reconnect_client(struct mqtt_client* client, void **reconnect_state_vptr)
+{
+    struct reconnect_state_t *reconnect_state = *((struct reconnect_state_t**) reconnect_state_vptr);
+
+    /* Close the clients socket if this isn't the initial reconnect call */
+    if (client->error != MQTT_ERROR_INITIAL_RECONNECT) {
+        close(client->socketfd);
+    }
+
+    /* Perform error handling here. */
+    if (client->error != MQTT_ERROR_INITIAL_RECONNECT) {
+        printf("reconnect_client: called while client was in error state \"%s\"\n", 
+               mqtt_error_str(client->error)
+        );
+    }
+
+    /* Open a new socket. */
+    int sockfd = open_nb_socket(reconnect_state->hostname, reconnect_state->port);
+    if (sockfd == -1) {
+        perror("Failed to open socket: ");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* Reinitialize the client. */
+    mqtt_reinit(client, sockfd, 
+                reconnect_state->sendbuf, reconnect_state->sendbufsz,
+                reconnect_state->recvbuf, reconnect_state->recvbufsz
+    );
+
+    /* Create an anonymous session */
+    const char* client_id = NULL;
+    /* Ensure we have a clean session */
+    uint8_t connect_flags = MQTT_CONNECT_CLEAN_SESSION;
+    /* Send connection request to the broker. */
+    mqtt_connect(client, client_id, NULL, NULL, 0, NULL, NULL, connect_flags, 400);
+
+    /* Subscribe to the topic. */
+    mqtt_subscribe(client, reconnect_state->topic, 0);
+}
+
+void exit_example(int status, int sockfd, pthread_t *client_daemon)
+{
+    if (sockfd != -1) close(sockfd);
+    if (client_daemon != NULL) pthread_cancel(*client_daemon);
+    exit(status);
+}
+
+void publish_callback(void** unused, struct mqtt_response_publish *published) 
+{
+    /* note that published->topic_name is NOT null-terminated (here we'll change it to a c-string) */
+    char* topic_name = (char*) malloc(published->topic_name_size + 1);
+    memcpy(topic_name, published->topic_name, published->topic_name_size);
+    topic_name[published->topic_name_size] = '\0';
+
+    printf("Received publish('%s'): %s\n", topic_name, (const char*) published->application_message);
+
+    free(topic_name);
+}
+
+void* client_refresher(void* client)
+{
+    while(1) 
+    {
+        mqtt_sync((struct mqtt_client*) client);
+        usleep(100000U);
+    }
+    return NULL;
+}
\ No newline at end of file

deps/MQTT-C/examples/simple_publisher.c

+
+/**
+ * @file
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mqtt.h>
+#include "templates/posix_sockets.h"
+
+
+/**
+ * @brief The function that would be called whenever a PUBLISH is received.
+ * 
+ * @note This function is not used in this example. 
+ */
+void publish_callback(void** unused, struct mqtt_response_publish *published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to 
+ *        handle ingress/egress traffic to the broker.
+ * 
+ * @note All this function needs to do is call \ref __mqtt_recv and 
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that 
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* client_refresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit. 
+ */
+void exit_example(int status, int sockfd, pthread_t *client_daemon);
+
+/**
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ */
+int main(int argc, const char *argv[]) 
+{
+    const char* addr;
+    const char* port;
+    const char* topic;
+
+    /* get address (argv[1] if present) */
+    if (argc > 1) {
+        addr = argv[1];
+    } else {
+        addr = "test.mosquitto.org";
+    }
+
+    /* get port number (argv[2] if present) */
+    if (argc > 2) {
+        port = argv[2];
+    } else {
+        port = "1883";
+    }
+
+    /* get the topic name to publish */
+    if (argc > 3) {
+        topic = argv[3];
+    } else {
+        topic = "datetime";
+    }
+
+    /* open the non-blocking TCP socket (connecting to the broker) */
+    int sockfd = open_nb_socket(addr, port);
+
+    if (sockfd == -1) {
+        perror("Failed to open socket: ");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* setup a client */
+    struct mqtt_client client;
+    uint8_t sendbuf[2048]; /* sendbuf should be large enough to hold multiple whole mqtt messages */
+    uint8_t recvbuf[1024]; /* recvbuf should be large enough any whole mqtt message expected to be received */
+    mqtt_init(&client, sockfd, sendbuf, sizeof(sendbuf), recvbuf, sizeof(recvbuf), publish_callback);
+    /* Create an anonymous session */
+    const char* client_id = NULL;
+    /* Ensure we have a clean session */
+    uint8_t connect_flags = MQTT_CONNECT_CLEAN_SESSION;
+    /* Send connection request to the broker. */
+    mqtt_connect(&client, client_id, NULL, NULL, 0, NULL, NULL, connect_flags, 400);
+
+    /* check that we don't have any errors */
+    if (client.error != MQTT_OK) {
+        fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* start a thread to refresh the client (handle egress and ingree client traffic) */
+    pthread_t client_daemon;
+    if(pthread_create(&client_daemon, NULL, client_refresher, &client)) {
+        fprintf(stderr, "Failed to start client daemon.\n");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+
+    }
+
+    /* start publishing the time */
+    printf("%s is ready to begin publishing the time.\n", argv[0]);
+    printf("Press ENTER to publish the current time.\n");
+    printf("Press CTRL-D (or any other key) to exit.\n\n");
+    while(fgetc(stdin) == '\n') {
+        /* get the current time */
+        time_t timer;
+        time(&timer);
+        struct tm* tm_info = localtime(&timer);
+        char timebuf[26];
+        strftime(timebuf, 26, "%Y-%m-%d %H:%M:%S", tm_info);
+
+        /* print a message */
+        char application_message[256];
+        snprintf(application_message, sizeof(application_message), "The time is %s", timebuf);
+        printf("%s published : \"%s\"", argv[0], application_message);
+
+        /* publish the time */
+        mqtt_publish(&client, topic, application_message, strlen(application_message) + 1, MQTT_PUBLISH_QOS_0);
+
+        /* check for errors */
+        if (client.error != MQTT_OK) {
+            fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+            exit_example(EXIT_FAILURE, sockfd, &client_daemon);
+        }
+    }   
+
+    /* disconnect */
+    printf("\n%s disconnecting from %s\n", argv[0], addr);
+    sleep(1);
+
+    /* exit */ 
+    exit_example(EXIT_SUCCESS, sockfd, &client_daemon);
+}
+
+void exit_example(int status, int sockfd, pthread_t *client_daemon)
+{
+    if (sockfd != -1) close(sockfd);
+    if (client_daemon != NULL) pthread_cancel(*client_daemon);
+    exit(status);
+}
+
+
+
+void publish_callback(void** unused, struct mqtt_response_publish *published) 
+{
+    /* not used in this example */
+}
+
+void* client_refresher(void* client)
+{
+    while(1) 
+    {
+        mqtt_sync((struct mqtt_client*) client);
+        usleep(100000U);
+    }
+    return NULL;
+}
\ No newline at end of file

deps/MQTT-C/examples/simple_subscriber.c

+
+/**
+ * @file
+ * A simple program that subscribes to a topic.
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mqtt.h>
+#include "templates/posix_sockets.h"
+
+
+/**
+ * @brief The function will be called whenever a PUBLISH message is received.
+ */
+void publish_callback(void** unused, struct mqtt_response_publish *published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to 
+ *        handle ingress/egress traffic to the broker.
+ * 
+ * @note All this function needs to do is call \ref __mqtt_recv and 
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that 
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* client_refresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit. 
+ */
+void exit_example(int status, int sockfd, pthread_t *client_daemon);
+
+int main(int argc, const char *argv[]) 
+{
+    const char* addr;
+    const char* port;
+    const char* topic;
+
+    /* get address (argv[1] if present) */
+    if (argc > 1) {
+        addr = argv[1];
+    } else {
+        addr = "test.mosquitto.org";
+    }
+
+    /* get port number (argv[2] if present) */
+    if (argc > 2) {
+        port = argv[2];
+    } else {
+        port = "1883";
+    }
+
+    /* get the topic name to publish */
+    if (argc > 3) {
+        topic = argv[3];
+    } else {
+        topic = "datetime";
+    }
+
+    /* open the non-blocking TCP socket (connecting to the broker) */
+    int sockfd = open_nb_socket(addr, port);
+
+    if (sockfd == -1) {
+        perror("Failed to open socket: ");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* setup a client */
+    struct mqtt_client client;
+    uint8_t sendbuf[2048]; /* sendbuf should be large enough to hold multiple whole mqtt messages */
+    uint8_t recvbuf[1024]; /* recvbuf should be large enough any whole mqtt message expected to be received */
+    mqtt_init(&client, sockfd, sendbuf, sizeof(sendbuf), recvbuf, sizeof(recvbuf), publish_callback);
+    /* Create an anonymous session */
+    const char* client_id = NULL;
+    /* Ensure we have a clean session */
+    uint8_t connect_flags = MQTT_CONNECT_CLEAN_SESSION;
+    /* Send connection request to the broker. */
+    mqtt_connect(&client, client_id, NULL, NULL, 0, NULL, NULL, connect_flags, 400);
+
+    /* check that we don't have any errors */
+    if (client.error != MQTT_OK) {
+        fprintf(stderr, "error: %s\n", mqtt_error_str(client.error));
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+    }
+
+    /* start a thread to refresh the client (handle egress and ingree client traffic) */
+    pthread_t client_daemon;
+    if(pthread_create(&client_daemon, NULL, client_refresher, &client)) {
+        fprintf(stderr, "Failed to start client daemon.\n");
+        exit_example(EXIT_FAILURE, sockfd, NULL);
+
+    }
+
+    /* subscribe */
+    mqtt_subscribe(&client, topic, 0);
+
+    /* start publishing the time */
+    printf("%s listening for '%s' messages.\n", argv[0], topic);
+    printf("Press CTRL-D to exit.\n\n");
+    
+    /* block */
+    while(fgetc(stdin) != EOF); 
+    
+    /* disconnect */
+    printf("\n%s disconnecting from %s\n", argv[0], addr);
+    sleep(1);
+
+    /* exit */ 
+    exit_example(EXIT_SUCCESS, sockfd, &client_daemon);
+}
+
+void exit_example(int status, int sockfd, pthread_t *client_daemon)
+{
+    if (sockfd != -1) close(sockfd);
+    if (client_daemon != NULL) pthread_cancel(*client_daemon);
+    exit(status);
+}
+
+
+
+void publish_callback(void** unused, struct mqtt_response_publish *published) 
+{
+    /* note that published->topic_name is NOT null-terminated (here we'll change it to a c-string) */
+    char* topic_name = (char*) malloc(published->topic_name_size + 1);
+    memcpy(topic_name, published->topic_name, published->topic_name_size);
+    topic_name[published->topic_name_size] = '\0';
+
+    printf("Received publish('%s'): %s\n", topic_name, (const char*) published->application_message);
+
+    free(topic_name);
+}
+
+void* client_refresher(void* client)
+{
+    while(1) 
+    {
+        mqtt_sync((struct mqtt_client*) client);
+        usleep(100000U);
+    }
+    return NULL;
+}
\ No newline at end of file

deps/MQTT-C/examples/templates/bio_sockets.h

+#ifndef __BIO_SOCKET_TEMPLATE_H__
+#define __BIO_SOCKET_TEMPLATE_H__
+
+#include <openssl/bio.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+
+/*
+    A template for opening a non-blocking BIO socket.
+*/
+BIO* open_nb_socket(const char* addr, const char* port) {
+    BIO* bio = BIO_new_connect(addr);
+    BIO_set_nbio(bio, 1);
+    BIO_set_conn_port(bio, port);
+
+    /* timeout after 10 seconds */
+    int start_time = time(NULL);
+    while(BIO_do_connect(bio) == 0 && (int)time(NULL) - start_time < 10);
+
+    if (BIO_do_connect(bio) <= 0) {
+        fprintf(stderr, "Failed to open socket: BIO_do_connect returned <= 0\n");
+        return NULL;
+    }
+
+    return bio; 
+}
+
+#endif
\ No newline at end of file

deps/MQTT-C/examples/templates/mbedtls_sockets.h

+#ifndef __MBEDTLS_SOCKET_TEMPLATE_H__
+#define __MBEDTLS_SOCKET_TEMPLATE_H__
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <mbedtls/error.h>
+#include <mbedtls/entropy.h>
+#include <mbedtls/ctr_drbg.h>
+#include <mbedtls/net_sockets.h>
+#include <mbedtls/ssl.h>
+
+#if !defined(MBEDTLS_NET_POLL_READ)
+/* compat for older mbedtls */
+#define	MBEDTLS_NET_POLL_READ	1
+#define	MBEDTLS_NET_POLL_WRITE	1
+
+int
+mbedtls_net_poll(mbedtls_net_context * ctx, uint32_t rw, uint32_t timeout)
+{
+	/* XXX this is not ideal but good enough for an example */
+	usleep(300);
+	return 1;
+}
+#endif
+
+struct mbedtls_context {
+    mbedtls_net_context net_ctx;
+    mbedtls_ssl_context ssl_ctx;
+    mbedtls_ssl_config ssl_conf;
+    mbedtls_x509_crt ca_crt;
+    mbedtls_entropy_context entropy;
+    mbedtls_ctr_drbg_context ctr_drbg;
+};
+
+void failed(const char *fn, int rv) {
+    char buf[100];
+    mbedtls_strerror(rv, buf, sizeof(buf));
+    printf("%s failed with %x (%s)\n", fn, -rv, buf);
+    exit(1);
+}
+
+void cert_verify_failed(uint32_t rv) {
+    char buf[512];
+    mbedtls_x509_crt_verify_info(buf, sizeof(buf), "\t", rv);
+    printf("Certificate verification failed (%0" PRIx32 ")\n%s\n", rv, buf);
+    exit(1);
+}
+
+/*
+    A template for opening a non-blocking mbed TLS connection.
+*/
+void open_nb_socket(struct mbedtls_context *ctx,
+                    const char *hostname,
+                    const char *port,
+                    const char *ca_file) {
+    const unsigned char *additional = (const unsigned char *)"MQTT-C";
+    size_t additional_len = 6;
+    int rv;
+
+    mbedtls_net_context *net_ctx = &ctx->net_ctx;
+    mbedtls_ssl_context *ssl_ctx = &ctx->ssl_ctx;
+    mbedtls_ssl_config *ssl_conf = &ctx->ssl_conf;
+    mbedtls_x509_crt *ca_crt = &ctx->ca_crt;
+    mbedtls_entropy_context *entropy = &ctx->entropy;
+    mbedtls_ctr_drbg_context *ctr_drbg = &ctx->ctr_drbg;
+
+    mbedtls_entropy_init(entropy);
+    mbedtls_ctr_drbg_init(ctr_drbg);
+    rv = mbedtls_ctr_drbg_seed(ctr_drbg, mbedtls_entropy_func, entropy,
+                               additional, additional_len);
+    if (rv != 0) {
+        failed("mbedtls_ctr_drbg_seed", rv);
+    }
+
+    mbedtls_x509_crt_init(ca_crt);
+    rv = mbedtls_x509_crt_parse_file(ca_crt, ca_file);
+    if (rv != 0) {
+        failed("mbedtls_x509_crt_parse_file", rv);
+    }
+
+    mbedtls_ssl_config_init(ssl_conf);
+    rv = mbedtls_ssl_config_defaults(ssl_conf,  MBEDTLS_SSL_IS_CLIENT,
+                                     MBEDTLS_SSL_TRANSPORT_STREAM,
+                                     MBEDTLS_SSL_PRESET_DEFAULT);
+    if (rv != 0) {
+        failed("mbedtls_ssl_config_defaults", rv);
+    }
+    mbedtls_ssl_conf_ca_chain(ssl_conf, ca_crt, NULL);
+    mbedtls_ssl_conf_authmode(ssl_conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
+    mbedtls_ssl_conf_rng(ssl_conf, mbedtls_ctr_drbg_random, ctr_drbg);
+
+    mbedtls_net_init(net_ctx);
+    rv = mbedtls_net_connect(net_ctx, hostname, port, MBEDTLS_NET_PROTO_TCP);
+    if (rv != 0) {
+        failed("mbedtls_net_connect", rv);
+    }
+    rv = mbedtls_net_set_nonblock(net_ctx);
+    if (rv != 0) {
+        failed("mbedtls_net_set_nonblock", rv);
+    }
+
+    mbedtls_ssl_init(ssl_ctx);
+    rv = mbedtls_ssl_setup(ssl_ctx, ssl_conf);
+    if (rv != 0) {
+        failed("mbedtls_ssl_setup", rv);
+    }
+    rv = mbedtls_ssl_set_hostname(ssl_ctx, hostname);
+    if (rv != 0) {
+        failed("mbedtls_ssl_set_hostname", rv);
+    }
+    mbedtls_ssl_set_bio(ssl_ctx, net_ctx,
+                        mbedtls_net_send, mbedtls_net_recv, NULL);
+
+    for (;;) {
+        rv = mbedtls_ssl_handshake(ssl_ctx);
+        uint32_t want = 0;
+        if (rv == MBEDTLS_ERR_SSL_WANT_READ) {
+            want |= MBEDTLS_NET_POLL_READ;
+        } else if (rv == MBEDTLS_ERR_SSL_WANT_WRITE) {
+            want |= MBEDTLS_NET_POLL_WRITE;
+        } else {
+            break;
+        }
+        rv = mbedtls_net_poll(net_ctx, want, -1);
+        if (rv < 0) {
+            failed("mbedtls_net_poll", rv);
+        }
+    }
+    if (rv != 0) {
+        failed("mbedtls_ssl_handshake", rv);
+    }
+    uint32_t result = mbedtls_ssl_get_verify_result(ssl_ctx);
+    if (result != 0) {
+        if (result == (uint32_t)-1) {
+            failed("mbedtls_ssl_get_verify_result", result);
+        } else {
+            cert_verify_failed(result);
+        }
+    }
+}
+
+#endif

deps/MQTT-C/examples/templates/openssl_sockets.h

+#ifndef __OPENSSL_SOCKET_TEMPLATE_H__
+#define __OPENSSL_SOCKET_TEMPLATE_H__
+
+#include <openssl/bio.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+
+/*
+    A template for opening a non-blocking OpenSSL connection.
+*/
+void open_nb_socket(BIO** bio, SSL_CTX** ssl_ctx, const char* addr, const char* port, const char* ca_file, const char* ca_path) {
+    *ssl_ctx = SSL_CTX_new(SSLv23_client_method());
+    SSL* ssl;
+
+    /* load certificate */
+    if (!SSL_CTX_load_verify_locations(*ssl_ctx, ca_file, ca_path)) {
+        printf("error: failed to load certificate\n");
+        exit(1);
+    }
+
+    /* open BIO socket */
+    *bio = BIO_new_ssl_connect(*ssl_ctx);
+    BIO_get_ssl(*bio, &ssl);
+    SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
+    BIO_set_conn_hostname(*bio, addr);
+    BIO_set_nbio(*bio, 1);
+    BIO_set_conn_port(*bio, port);
+
+    /* wait for connect with 10 second timeout */
+    int start_time = time(NULL);
+    int do_connect_rv = BIO_do_connect(*bio);
+    while(do_connect_rv <= 0 && BIO_should_retry(*bio) && (int)time(NULL) - start_time < 10) {
+        do_connect_rv = BIO_do_connect(*bio);
+    }
+    if (do_connect_rv <= 0) {
+        printf("error: %s\n", ERR_reason_error_string(ERR_get_error()));
+        BIO_free_all(*bio);
+        SSL_CTX_free(*ssl_ctx);
+        *bio = NULL;
+        *ssl_ctx=NULL;
+        return;
+    }
+
+    /* verify certificate */
+    if (SSL_get_verify_result(ssl) != X509_V_OK) {
+        /* Handle the failed verification */
+        printf("error: x509 certificate verification failed\n");
+        exit(1);
+    }
+}
+
+#endif
\ No newline at end of file

deps/MQTT-C/examples/templates/posix_sockets.h

+#ifndef __POSIX_SOCKET_TEMPLATE_H__
+#define __POSIX_SOCKET_TEMPLATE_H__
+
+#include <stdio.h>
+#include <sys/types.h>
+#if !defined(WIN32)
+#include <sys/socket.h>
+#include <netdb.h>
+#endif
+#include <fcntl.h>
+
+/*
+    A template for opening a non-blocking POSIX socket.
+*/
+int open_nb_socket(const char* addr, const char* port) {
+    struct addrinfo hints = {0};
+
+    hints.ai_family = AF_UNSPEC; /* IPv4 or IPv6 */
+    hints.ai_socktype = SOCK_STREAM; /* Must be TCP */
+    int sockfd = -1;
+    int rv;
+    struct addrinfo *p, *servinfo;
+
+    /* get address information */
+    rv = getaddrinfo(addr, port, &hints, &servinfo);
+    if(rv != 0) {
+        fprintf(stderr, "Failed to open socket (getaddrinfo): %s\n", gai_strerror(rv));
+        return -1;
+    }
+
+    /* open the first possible socket */
+    for(p = servinfo; p != NULL; p = p->ai_next) {
+        sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
+        if (sockfd == -1) continue;
+
+        /* connect to server */
+        rv = connect(sockfd, servinfo->ai_addr, servinfo->ai_addrlen);
+        if(rv == -1) continue;
+        break;
+    }  
+
+    /* free servinfo */
+    freeaddrinfo(servinfo);
+
+    /* make non-blocking */
+#if !defined(WIN32)
+    if (sockfd != -1) fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFL) | O_NONBLOCK);
+#else
+    if (sockfd != INVALID_SOCKET) {
+        int iMode = 1;
+        ioctlsocket(sockfd, FIONBIO, &iMode);
+    }
+#endif
+
+    /* return the new socket fd */
+    return sockfd;
+}
+
+#endif
\ No newline at end of file

deps/MQTT-C/include/mqtt.h

+#ifndef __MQTT_H__
+#define __MQTT_H__
+
+/*
+MIT License
+
+Copyright(c) 2018 Liam Bindle
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#include <mqtt_pal.h>
+
+/**
+ * @file
+ * @brief Declares all the MQTT-C functions and datastructures.
+ * 
+ * @note You should <code>\#include <mqtt.h></code>.
+ * 
+ * @example simple_publisher.c
+ * A simple program to that publishes the current time whenever ENTER is pressed. 
+ * 
+ * Usage:
+ * \code{.sh}
+ * ./bin/simple_publisher [address [port [topic]]]
+ * \endcode     
+ * 
+ * Where \c address is the address of the MQTT broker, \c port is the port number the 
+ * MQTT broker is running on, and \c topic is the name of the topic to publish with. Note
+ * that all these arguments are optional and the defaults are \c address = \c "test.mosquitto.org",
+ * \c port = \c "1883", and \c topic = "datetime".
+ * 
+ * @example simple_subscriber.c
+ * A simple program that subscribes to a single topic and prints all updates that are received.
+ * 
+ * Usage:
+ * \code{.sh}
+ * ./bin/simple_subscriber [address [port [topic]]]
+ * \endcode   
+ * 
+ * Where \c address is the address of the MQTT broker, \c port is the port number the 
+ * MQTT broker is running on, and \c topic is the name of the topic subscribe to. Note
+ * that all these arguments are optional and the defaults are \c address = \c "test.mosquitto.org",
+ * \c port = \c "1883", and \c topic = "datetime".  
+ * 
+ * @example reconnect_subscriber.c
+ * Same program as \ref simple_subscriber.c, but using the automatic reconnect functionality. 
+ * 
+ * @example bio_publisher.c
+ * Same program as \ref simple_publisher.c, but uses a unencrypted BIO socket.
+ *
+ * @example openssl_publisher.c
+ * Same program as \ref simple_publisher.c, but over an encrypted connection using OpenSSL.
+ * 
+ * Usage:
+ * \code{.sh}
+ * ./bin/openssl_publisher ca_file [address [port [topic]]]
+ * \endcode   
+ * 
+ * 
+ * @defgroup api API
+ * @brief Documentation of everything you need to know to use the MQTT-C client.
+ * 
+ * This module contains everything you need to know to use MQTT-C in your application.
+ * For usage examples see:
+ *     - @ref simple_publisher.c
+ *     - @ref simple_subscriber.c
+ *     - @ref reconnect_subscriber.c
+ *     - @ref bio_publisher.c
+ *     - @ref openssl_publisher.c
+ * 
+ * @note MQTT-C can be used in both single-threaded and multi-threaded applications. All 
+ *       the functions in \ref api are thread-safe.
+ * 
+ * @defgroup packers Control Packet Serialization
+ * @brief Developer documentation of the functions and datastructures used for serializing MQTT 
+ *        control packets.
+ * 
+ * @defgroup unpackers Control Packet Deserialization
+ * @brief Developer documentation of the functions and datastructures used for deserializing MQTT 
+ *        control packets.
+ * 
+ * @defgroup details Utilities
+ * @brief Developer documentation for the utilities used to implement the MQTT-C client.
+ *
+ * @note To deserialize a packet from a buffer use \ref mqtt_unpack_response (it's the only 
+ *       function you need).
+ */
+
+
+ /**
+  * @brief An enumeration of the MQTT control packet types. 
+  * @ingroup unpackers
+  *
+  * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718021">
+  * MQTT v3.1.1: MQTT Control Packet Types
+  * </a>
+  */
+  enum MQTTControlPacketType {
+    MQTT_CONTROL_CONNECT=1u,
+    MQTT_CONTROL_CONNACK=2u,
+    MQTT_CONTROL_PUBLISH=3u,
+    MQTT_CONTROL_PUBACK=4u,
+    MQTT_CONTROL_PUBREC=5u,
+    MQTT_CONTROL_PUBREL=6u,
+    MQTT_CONTROL_PUBCOMP=7u,
+    MQTT_CONTROL_SUBSCRIBE=8u,
+    MQTT_CONTROL_SUBACK=9u,
+    MQTT_CONTROL_UNSUBSCRIBE=10u,
+    MQTT_CONTROL_UNSUBACK=11u,
+    MQTT_CONTROL_PINGREQ=12u,
+    MQTT_CONTROL_PINGRESP=13u,
+    MQTT_CONTROL_DISCONNECT=14u
+};
+
+/**
+ * @brief The fixed header of an MQTT control packet.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718020">
+ * MQTT v3.1.1: Fixed Header
+ * </a>
+ */
+struct mqtt_fixed_header {
+    /** The type of packet. */
+    enum MQTTControlPacketType control_type;
+
+    /** The packets control flags.*/
+    uint32_t  control_flags: 4;
+
+    /** The remaining size of the packet in bytes (i.e. the size of variable header and payload).*/
+    uint32_t remaining_length;
+};
+
+/**
+ * @brief The protocol identifier for MQTT v3.1.1.
+ * @ingroup packers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718030">
+ * MQTT v3.1.1: CONNECT Variable Header.
+ * </a>  
+ */
+#define MQTT_PROTOCOL_LEVEL 0x04
+
+/** 
+ * @brief A macro used to declare the enum MQTTErrors and associated 
+ *        error messages (the members of the num) at the same time.
+ */
+#define __ALL_MQTT_ERRORS(MQTT_ERROR)                    \
+    MQTT_ERROR(MQTT_ERROR_NULLPTR)                       \
+    MQTT_ERROR(MQTT_ERROR_CONTROL_FORBIDDEN_TYPE)        \
+    MQTT_ERROR(MQTT_ERROR_CONTROL_INVALID_FLAGS)         \
+    MQTT_ERROR(MQTT_ERROR_CONTROL_WRONG_TYPE)            \
+    MQTT_ERROR(MQTT_ERROR_CONNECT_CLIENT_ID_REFUSED)     \
+    MQTT_ERROR(MQTT_ERROR_CONNECT_NULL_WILL_MESSAGE)     \
+    MQTT_ERROR(MQTT_ERROR_CONNECT_FORBIDDEN_WILL_QOS)    \
+    MQTT_ERROR(MQTT_ERROR_CONNACK_FORBIDDEN_FLAGS)       \
+    MQTT_ERROR(MQTT_ERROR_CONNACK_FORBIDDEN_CODE)        \
+    MQTT_ERROR(MQTT_ERROR_PUBLISH_FORBIDDEN_QOS)         \
+    MQTT_ERROR(MQTT_ERROR_SUBSCRIBE_TOO_MANY_TOPICS)     \
+    MQTT_ERROR(MQTT_ERROR_MALFORMED_RESPONSE)            \
+    MQTT_ERROR(MQTT_ERROR_UNSUBSCRIBE_TOO_MANY_TOPICS)   \
+    MQTT_ERROR(MQTT_ERROR_RESPONSE_INVALID_CONTROL_TYPE) \
+    MQTT_ERROR(MQTT_ERROR_CONNECT_NOT_CALLED)          \
+    MQTT_ERROR(MQTT_ERROR_SEND_BUFFER_IS_FULL)           \
+    MQTT_ERROR(MQTT_ERROR_SOCKET_ERROR)                  \
+    MQTT_ERROR(MQTT_ERROR_MALFORMED_REQUEST)             \
+    MQTT_ERROR(MQTT_ERROR_RECV_BUFFER_TOO_SMALL)         \
+    MQTT_ERROR(MQTT_ERROR_ACK_OF_UNKNOWN)                \
+    MQTT_ERROR(MQTT_ERROR_NOT_IMPLEMENTED)               \
+    MQTT_ERROR(MQTT_ERROR_CONNECTION_REFUSED)            \
+    MQTT_ERROR(MQTT_ERROR_SUBSCRIBE_FAILED)              \
+    MQTT_ERROR(MQTT_ERROR_CONNECTION_CLOSED)             \
+    MQTT_ERROR(MQTT_ERROR_INITIAL_RECONNECT)             \
+    MQTT_ERROR(MQTT_ERROR_INVALID_REMAINING_LENGTH)      \
+    MQTT_ERROR(MQTT_ERROR_CLEAN_SESSION_IS_REQUIRED)
+
+/* todo: add more connection refused errors */
+
+/** 
+ * @brief A macro used to generate the enum MQTTErrors from 
+ *        \ref __ALL_MQTT_ERRORS
+ * @see __ALL_MQTT_ERRORS
+*/
+#define GENERATE_ENUM(ENUM) ENUM,
+
+/** 
+ * @brief A macro used to generate the error messages associated with 
+ *        MQTTErrors from \ref __ALL_MQTT_ERRORS
+ * @see __ALL_MQTT_ERRORS
+*/
+#define GENERATE_STRING(STRING) #STRING,
+
+
+/** 
+ * @brief An enumeration of error codes. Error messages can be retrieved by calling \ref mqtt_error_str.
+ * @ingroup api
+ * 
+ * @see mqtt_error_str
+ */
+enum MQTTErrors {
+    MQTT_ERROR_UNKNOWN=INT_MIN,
+    __ALL_MQTT_ERRORS(GENERATE_ENUM)
+    MQTT_OK = 1
+};
+
+/** 
+ * @brief Returns an error message for error code, \p error.
+ * @ingroup api
+ * 
+ * @param[in] error the error code.
+ * 
+ * @returns The associated error message.
+ */
+const char* mqtt_error_str(enum MQTTErrors error);
+
+/**
+ * @brief Pack a MQTT 16 bit integer, given a native 16 bit integer .
+ * 
+ * @param[out] buf the buffer that the MQTT integer will be written to.
+ * @param[in] integer the native integer to be written to \p buf.
+ * 
+ * @warning This function provides no error checking.
+ * 
+ * @returns 2
+*/
+ssize_t __mqtt_pack_uint16(uint8_t *buf, uint16_t integer);
+
+/**
+ * @brief Unpack a MQTT 16 bit integer to a native 16 bit integer.
+ * 
+ * @param[in] buf the buffer that the MQTT integer will be read from.
+ * 
+ * @warning This function provides no error checking and does not modify \p buf.
+ * 
+ * @returns The native integer
+*/
+uint16_t __mqtt_unpack_uint16(const uint8_t *buf);
+
+/**
+ * @brief Pack a MQTT string, given a c-string \p str.
+ * 
+ * @param[out] buf the buffer that the MQTT string will be written to.
+ * @param[in] str the c-string to be written to \p buf.
+ * 
+ * @warning This function provides no error checking.
+ * 
+ * @returns strlen(str) + 2
+*/
+ssize_t __mqtt_pack_str(uint8_t *buf, const char* str);
+
+/** @brief A macro to get the MQTT string length from a c-string. */
+#define __mqtt_packed_cstrlen(x) (2 + strlen(x))
+
+/* RESPONSES */
+
+/**
+ * @brief An enumeration of the return codes returned in a CONNACK packet.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Table_3.1_-">
+ * MQTT v3.1.1: CONNACK return codes.
+ * </a> 
+ */
+enum MQTTConnackReturnCode {
+    MQTT_CONNACK_ACCEPTED = 0u,
+    MQTT_CONNACK_REFUSED_PROTOCOL_VERSION = 1u,
+    MQTT_CONNACK_REFUSED_IDENTIFIER_REJECTED = 2u,
+    MQTT_CONNACK_REFUSED_SERVER_UNAVAILABLE = 3u,
+    MQTT_CONNACK_REFUSED_BAD_USER_NAME_OR_PASSWORD = 4u,
+    MQTT_CONNACK_REFUSED_NOT_AUTHORIZED = 5u
+};
+
+/**
+ * @brief A connection response datastructure.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718033">
+ * MQTT v3.1.1: CONNACK - Acknowledgement connection response.
+ * </a>
+ */
+struct mqtt_response_connack {
+    /** 
+     * @brief Allows client and broker to check if they have a consistent view about whether there is
+     * already a stored session state.
+    */
+    uint8_t session_present_flag;
+
+    /** 
+     * @brief The return code of the connection request. 
+     * 
+     * @see MQTTConnackReturnCode
+     */
+    enum MQTTConnackReturnCode return_code;
+};
+
+ /**
+  * @brief A publish packet received from the broker.
+  * @ingroup unpackers
+  * 
+  * A publish packet is received from the broker when a client publishes to a topic that the 
+  * \em {local client} is subscribed to.
+  *
+  * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718037"> 
+  * MQTT v3.1.1: PUBLISH - Publish Message.
+  * </a> 
+  */
+struct mqtt_response_publish {
+    /** 
+     * @brief The DUP flag. DUP flag is 0 if its the first attempt to send this publish packet. A DUP flag
+     * of 1 means that this might be a re-delivery of the packet.
+     */
+    uint8_t dup_flag;
+
+    /** 
+     * @brief The quality of service level.
+     * 
+     * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Table_3.11_-">
+     * MQTT v3.1.1: QoS Definitions
+     * </a>
+     */
+    uint8_t qos_level;
+
+    /** @brief The retain flag of this publish message. */
+    uint8_t retain_flag;
+
+    /** @brief Size of the topic name (number of characters). */
+    uint16_t topic_name_size;
+
+    /** 
+     * @brief The topic name. 
+     * @note topic_name is not null terminated. Therefore topic_name_size must be used to get the 
+     *       string length.
+     */
+    const void* topic_name;
+
+    /** @brief The publish message's packet ID. */
+    uint16_t packet_id;
+
+    /** @brief The publish message's application message.*/
+    const void* application_message;
+
+    /** @brief The size of the application message in bytes. */
+    size_t application_message_size;
+};
+
+/**
+ * @brief A publish acknowledgement for messages that were published with QoS level 1.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718043">
+ * MQTT v3.1.1: PUBACK - Publish Acknowledgement.
+ * </a> 
+ *
+ */
+struct mqtt_response_puback {
+    /** @brief The published messages packet ID. */
+    uint16_t packet_id;
+};
+
+/**
+ * @brief The response packet to a PUBLISH packet with QoS level 2.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718048">
+ * MQTT v3.1.1: PUBREC - Publish Received.
+ * </a> 
+ *
+ */
+struct mqtt_response_pubrec {
+    /** @brief The published messages packet ID. */
+    uint16_t packet_id;
+};
+
+/**
+ * @brief The response to a PUBREC packet.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718053">
+ * MQTT v3.1.1: PUBREL - Publish Release.
+ * </a> 
+ *
+ */
+struct mqtt_response_pubrel {
+    /** @brief The published messages packet ID. */
+    uint16_t packet_id;
+};
+
+/**
+ * @brief The response to a PUBREL packet.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718058">
+ * MQTT v3.1.1: PUBCOMP - Publish Complete.
+ * </a> 
+ *
+ */
+struct mqtt_response_pubcomp {
+    /** T@brief he published messages packet ID. */
+    uint16_t packet_id;
+};
+
+/**
+ * @brief An enumeration of subscription acknowledgement return codes.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Figure_3.26_-">
+ * MQTT v3.1.1: SUBACK Return Codes.
+ * </a> 
+ */
+enum MQTTSubackReturnCodes {
+    MQTT_SUBACK_SUCCESS_MAX_QOS_0 = 0u,
+    MQTT_SUBACK_SUCCESS_MAX_QOS_1 = 1u,
+    MQTT_SUBACK_SUCCESS_MAX_QOS_2 = 2u,
+    MQTT_SUBACK_FAILURE           = 128u
+};
+
+/**
+ * @brief The response to a subscription request.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718068">
+ * MQTT v3.1.1: SUBACK - Subscription Acknowledgement.
+ * </a> 
+ */
+struct mqtt_response_suback {
+    /** @brief The published messages packet ID. */
+    uint16_t packet_id;
+
+    /** 
+     * Array of return codes corresponding to the requested subscribe topics.
+     * 
+     * @see MQTTSubackReturnCodes
+     */
+    const uint8_t *return_codes;
+
+    /** The number of return codes. */
+    size_t num_return_codes;
+};
+
+/**
+ * @brief The brokers response to a UNSUBSCRIBE request.
+ * @ingroup unpackers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718077">
+ * MQTT v3.1.1: UNSUBACK - Unsubscribe Acknowledgement.
+ * </a> 
+ */
+struct mqtt_response_unsuback {
+    /** @brief The published messages packet ID. */
+    uint16_t packet_id;
+};
+
+/**
+ * @brief The response to a ping request.
+ * @ingroup unpackers
+ * 
+ * @note This response contains no members.
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718086">
+ * MQTT v3.1.1: PINGRESP - Ping Response.
+ * </a> 
+ */
+struct mqtt_response_pingresp {
+  int dummy;
+};
+
+/**
+ * @brief A struct used to deserialize/interpret an incoming packet from the broker.
+ * @ingroup unpackers
+ */
+struct mqtt_response {
+    /** @brief The mqtt_fixed_header of the deserialized packet. */
+    struct mqtt_fixed_header fixed_header;
+
+    /**
+     * @brief A union of the possible responses from the broker.
+     * 
+     * @note The fixed_header contains the control type. This control type corresponds to the
+     *       member of this union that should be accessed. For example if 
+     *       fixed_header#control_type == \c MQTT_CONTROL_PUBLISH then 
+     *       decoded#publish should be accessed.
+     */
+    union {
+        struct mqtt_response_connack  connack;
+        struct mqtt_response_publish  publish;
+        struct mqtt_response_puback   puback;
+        struct mqtt_response_pubrec   pubrec;
+        struct mqtt_response_pubrel   pubrel;
+        struct mqtt_response_pubcomp  pubcomp;
+        struct mqtt_response_suback   suback;
+        struct mqtt_response_unsuback unsuback;
+        struct mqtt_response_pingresp pingresp;
+    } decoded;
+};
+
+/**
+ * @brief Deserialize the contents of \p buf into an mqtt_fixed_header object.
+ * @ingroup unpackers
+ * 
+ * @note This function performs complete error checking and a positive return value
+ *       means the entire mqtt_response can be deserialized from \p buf.
+ * 
+ * @param[out] response the response who's \ref mqtt_response.fixed_header will be initialized.
+ * @param[in] buf the buffer.
+ * @param[in] bufsz the total number of bytes in the buffer.
+ * 
+ * @returns The number of bytes that were consumed, or 0 if the buffer does not contain enough 
+ *          bytes to parse the packet, or a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_unpack_fixed_header(struct mqtt_response *response, const uint8_t *buf, size_t bufsz);
+
+/**
+ * @brief Deserialize a CONNACK response from \p buf.
+ * @ingroup unpackers
+ * 
+ * @pre \ref mqtt_unpack_fixed_header must have returned a positive value and the control packet type
+ *      must be \c MQTT_CONTROL_CONNACK.
+ * 
+ * @param[out] mqtt_response the mqtt_response that will be initialized.
+ * @param[in] buf the buffer that contains the variable header and payload of the packet. The 
+ *                first byte of \p buf should be the first byte of the variable header.
+ * 
+ * @relates mqtt_response_connack 
+ * 
+ * @returns The number of bytes that were consumed, or 0 if the buffer does not contain enough 
+ *          bytes to parse the packet, or a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_unpack_connack_response (struct mqtt_response *mqtt_response, const uint8_t *buf);
+
+/**
+ * @brief Deserialize a publish response from \p buf.
+ * @ingroup unpackers
+ * 
+ * @pre \ref mqtt_unpack_fixed_header must have returned a positive value and the mqtt_response must
+ *      have a control type of \c MQTT_CONTROL_PUBLISH.
+ * 
+ * @param[out] mqtt_response the response that is initialized from the contents of \p buf.
+ * @param[in] buf the buffer with the incoming data.
+ * 
+ * @relates mqtt_response_publish 
+ * 
+ * @returns The number of bytes that were consumed, or 0 if the buffer does not contain enough 
+ *          bytes to parse the packet, or a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_unpack_publish_response (struct mqtt_response *mqtt_response, const uint8_t *buf);
+
+/**
+ * @brief Deserialize a PUBACK/PUBREC/PUBREL/PUBCOMP packet from \p buf.
+ * @ingroup unpackers
+ * 
+ * @pre \ref mqtt_unpack_fixed_header must have returned a positive value and the mqtt_response must
+ *      have a control type of \c MQTT_CONTROL_PUBACK, \c MQTT_CONTROL_PUBREC, \c MQTT_CONTROL_PUBREL
+ *      or \c MQTT_CONTROL_PUBCOMP.
+ * 
+ * @param[out] mqtt_response the response that is initialized from the contents of \p buf.
+ * @param[in] buf the buffer with the incoming data.
+ *
+ * @relates mqtt_response_puback mqtt_response_pubrec mqtt_response_pubrel mqtt_response_pubcomp
+ * 
+ * @returns The number of bytes that were consumed, or 0 if the buffer does not contain enough 
+ *          bytes to parse the packet, or a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_unpack_pubxxx_response(struct mqtt_response *mqtt_response, const uint8_t *buf);
+
+/**
+ * @brief Deserialize a SUBACK packet from \p buf.
+ * @ingroup unpacker
+ *  
+ * @pre \ref mqtt_unpack_fixed_header must have returned a positive value and the mqtt_response must
+ *      have a control type of \c MQTT_CONTROL_SUBACK.
+ * 
+ * @param[out] mqtt_response the response that is initialized from the contents of \p buf.
+ * @param[in] buf the buffer with the incoming data.
+ *
+ * @relates mqtt_response_suback
+ * 
+ * @returns The number of bytes that were consumed, or 0 if the buffer does not contain enough 
+ *          bytes to parse the packet, or a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_unpack_suback_response(struct mqtt_response *mqtt_response, const uint8_t *buf);
+
+/**
+ * @brief Deserialize an UNSUBACK packet from \p buf.
+ * @ingroup unpacker
+ *  
+ * @pre \ref mqtt_unpack_fixed_header must have returned a positive value and the mqtt_response must
+ *      have a control type of \c MQTT_CONTROL_UNSUBACK.
+ * 
+ * @param[out] mqtt_response the response that is initialized from the contents of \p buf.
+ * @param[in] buf the buffer with the incoming data.
+ *
+ * @relates mqtt_response_unsuback
+ * 
+ * @returns The number of bytes that were consumed, or 0 if the buffer does not contain enough 
+ *          bytes to parse the packet, or a negative value if there was a protocol violation.
+ */  
+ssize_t mqtt_unpack_unsuback_response(struct mqtt_response *mqtt_response, const uint8_t *buf);
+
+/**
+ * @brief Deserialize a packet from the broker.
+ * @ingroup unpackers
+ * 
+ * @param[out] response the mqtt_response that will be initialize from \p buf.
+ * @param[in] buf the incoming data buffer.
+ * @param[in] bufsz the number of bytes available in the buffer.
+ * 
+ * @relates mqtt_response
+ * 
+ * @returns The number of bytes consumed on success, zero \p buf does not contain enough bytes
+ *          to deserialize the packet, a negative value if a protocol violation was encountered.  
+ */
+ssize_t mqtt_unpack_response(struct mqtt_response* response, const uint8_t *buf, size_t bufsz);
+
+/* REQUESTS */
+
+ /**
+ * @brief Serialize an mqtt_fixed_header and write it to \p buf.
+ * @ingroup packers
+ * 
+ * @note This function performs complete error checking and a positive return value
+ *       guarantees the entire packet will fit into the given buffer.
+ * 
+ * @param[out] buf the buffer to write to.
+ * @param[in] bufsz the maximum number of bytes that can be put in to \p buf.
+ * @param[in] fixed_header the fixed header that will be serialized.
+ * 
+ * @returns The number of bytes written to \p buf, or 0 if \p buf is too small, or a 
+ *          negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_fixed_header(uint8_t *buf, size_t bufsz, const struct mqtt_fixed_header *fixed_header);
+
+/**
+ * @brief An enumeration of CONNECT packet flags.
+ * @ingroup packers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718030">
+ * MQTT v3.1.1: CONNECT Variable Header.
+ * </a> 
+ */
+enum MQTTConnectFlags {
+    MQTT_CONNECT_RESERVED = 1u,
+    MQTT_CONNECT_CLEAN_SESSION = 2u,
+    MQTT_CONNECT_WILL_FLAG = 4u,
+    MQTT_CONNECT_WILL_QOS_0 = (0u & 0x03) << 3,
+    MQTT_CONNECT_WILL_QOS_1 = (1u & 0x03) << 3,
+    MQTT_CONNECT_WILL_QOS_2 = (2u & 0x03) << 3,
+    MQTT_CONNECT_WILL_RETAIN = 32u,
+    MQTT_CONNECT_PASSWORD = 64u,
+    MQTT_CONNECT_USER_NAME = 128u
+};
+
+/**
+ * @brief Serialize a connection request into a buffer. 
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to pack the connection request packet into.
+ * @param[in] bufsz the number of bytes left in \p buf.
+ * @param[in] client_id the ID that identifies the local client. \p client_id can be NULL or an empty
+ *                      string for Anonymous clients.
+ * @param[in] will_topic the topic under which the local client's will message will be published.
+ *                       Set to \c NULL for no will message. If \p will_topic is not \c NULL a
+ *                       \p will_message must also be provided.
+ * @param[in] will_message the will message to be published upon a unsuccessful disconnection of
+ *                         the local client. Set to \c NULL if \p will_topic is \c NULL. 
+ *                         \p will_message must \em not be \c NULL if \p will_topic is not 
+ *                         \c NULL.
+ * @param[in] will_message_size The size of \p will_message in bytes.
+ * @param[in] user_name the username to be used to connect to the broker with. Set to \c NULL if 
+ *                      no username is required.
+ * @param[in] password the password to be used to connect to the broker with. Set to \c NULL if
+ *                     no password is required.
+ * @param[in] connect_flags additional MQTTConnectFlags to be set. The only flags that need to be
+ *                          set manually are \c MQTT_CONNECT_CLEAN_SESSION,
+ *                          \c MQTT_CONNECT_WILL_QOS_X (for \c X &isin; {0, 1, 2}), and 
+ *                          \c MQTT_CONNECT_WILL_RETAIN. Set to 0 if no additional flags are 
+ *                          required.
+ * @param[in] keep_alive the keep alive time in seconds. It is the responsibility of the clinet 
+ *                       to ensure packets are sent to the server \em {at least} this frequently.
+ * 
+ * @note If there is a \p will_topic and no additional \p connect_flags are given, then by 
+ *       default \p will_message will be published at QoS level 0.
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718028">
+ * MQTT v3.1.1: CONNECT - Client Requests a Connection to a Server.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the CONNECT 
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_connection_request(uint8_t* buf, size_t bufsz, 
+                                     const char* client_id,
+                                     const char* will_topic,
+                                     const void* will_message,
+                                     size_t will_message_size,
+                                     const char* user_name,
+                                     const char* password,
+                                     uint8_t connect_flags,
+                                     uint16_t keep_alive);
+
+/**
+ * @brief An enumeration of the PUBLISH flags.
+ * @ingroup packers
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718037">
+ * MQTT v3.1.1: PUBLISH - Publish Message.
+ * </a>
+ */
+enum MQTTPublishFlags {
+    MQTT_PUBLISH_DUP = 8u,
+    MQTT_PUBLISH_QOS_0 = ((0u << 1) & 0x06),
+    MQTT_PUBLISH_QOS_1 = ((1u << 1) & 0x06),
+    MQTT_PUBLISH_QOS_2 = ((2u << 1) & 0x06),
+    MQTT_PUBLISH_QOS_MASK = ((3u << 1) & 0x06),
+    MQTT_PUBLISH_RETAIN = 0x01
+};
+
+/**
+ * @brief Serialize a PUBLISH request and put it in \p buf.
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to put the PUBLISH packet in.
+ * @param[in] bufsz the maximum number of bytes that can be put into \p buf.
+ * @param[in] topic_name the topic to publish \p application_message under.
+ * @param[in] packet_id this packets packet ID.
+ * @param[in] application_message the application message to be published.
+ * @param[in] application_message_size the size of \p application_message in bytes.
+ * @param[in] publish_flags The flags to publish \p application_message with. These include
+ *                          the \c MQTT_PUBLISH_DUP flag, \c MQTT_PUBLISH_QOS_X (\c X &isin; 
+ *                          {0, 1, 2}), and \c MQTT_PUBLISH_RETAIN flag.
+ * 
+ * @note The default QoS is level 0.
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718037">
+ * MQTT v3.1.1: PUBLISH - Publish Message.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the PUBLISH 
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_publish_request(uint8_t *buf, size_t bufsz,
+                                  const char* topic_name,
+                                  uint16_t packet_id,
+                                  void* application_message,
+                                  size_t application_message_size,
+                                  uint8_t publish_flags);
+
+/**
+ * @brief Serialize a PUBACK, PUBREC, PUBREL, or PUBCOMP packet and put it in \p buf.
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to put the PUBXXX packet in.
+ * @param[in] bufsz the maximum number of bytes that can be put into \p buf.
+ * @param[in] control_type the type of packet. Must be one of: \c MQTT_CONTROL_PUBACK, 
+ *                         \c MQTT_CONTROL_PUBREC, \c MQTT_CONTROL_PUBREL, 
+ *                         or \c MQTT_CONTROL_PUBCOMP.
+ * @param[in] packet_id the packet ID of the packet being acknowledged.
+ * 
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718043">
+ * MQTT v3.1.1: PUBACK - Publish Acknowledgement.
+ * </a>
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718048">
+ * MQTT v3.1.1: PUBREC - Publish Received.
+ * </a>
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718053">
+ * MQTT v3.1.1: PUBREL - Publish Released.
+ * </a>
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718058">
+ * MQTT v3.1.1: PUBCOMP - Publish Complete.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the PUBXXX 
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_pubxxx_request(uint8_t *buf, size_t bufsz, 
+                                 enum MQTTControlPacketType control_type,
+                                 uint16_t packet_id);
+
+/** 
+ * @brief The maximum number topics that can be subscribed to in a single call to 
+ *         mqtt_pack_subscribe_request.
+ * @ingroup packers
+ * 
+ * @see mqtt_pack_subscribe_request
+ */
+#define MQTT_SUBSCRIBE_REQUEST_MAX_NUM_TOPICS 8
+
+/** 
+ * @brief Serialize a SUBSCRIBE packet and put it in \p buf.
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to put the SUBSCRIBE packet in.
+ * @param[in] bufsz the maximum number of bytes that can be put into \p buf.
+ * @param[in] packet_id the packet ID to be used.
+ * @param[in] ... \c NULL terminated list of (\c {const char *topic_name}, \c {int max_qos_level})
+ *                pairs.
+ * 
+ * @note The variadic arguments, \p ..., \em must be followed by a \c NULL. For example:
+ * @code
+ * ssize_t n = mqtt_pack_subscribe_request(buf, bufsz, 1234, "topic_1", 0, "topic_2", 2, NULL);
+ * @endcode
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718063">
+ * MQTT v3.1.1: SUBSCRIBE - Subscribe to Topics.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the SUBSCRIBE 
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_subscribe_request(uint8_t *buf, size_t bufsz, 
+                                    unsigned int packet_id, 
+                                    ...); /* null terminated */
+
+/** 
+ * @brief The maximum number topics that can be subscribed to in a single call to 
+ *         mqtt_pack_unsubscribe_request.
+ * @ingroup packers
+ * 
+ * @see mqtt_pack_unsubscribe_request
+ */
+#define MQTT_UNSUBSCRIBE_REQUEST_MAX_NUM_TOPICS 8
+
+/** 
+ * @brief Serialize a UNSUBSCRIBE packet and put it in \p buf.
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to put the UNSUBSCRIBE packet in.
+ * @param[in] bufsz the maximum number of bytes that can be put into \p buf.
+ * @param[in] packet_id the packet ID to be used.
+ * @param[in] ... \c NULL terminated list of \c {const char *topic_name}'s to unsubscribe from.
+ * 
+ * @note The variadic arguments, \p ..., \em must be followed by a \c NULL. For example:
+ * @code
+ * ssize_t n = mqtt_pack_unsubscribe_request(buf, bufsz, 4321, "topic_1", "topic_2", NULL);
+ * @endcode
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718072">
+ * MQTT v3.1.1: UNSUBSCRIBE - Unsubscribe from Topics.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the UNSUBSCRIBE 
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_unsubscribe_request(uint8_t *buf, size_t bufsz, 
+                                      unsigned int packet_id, 
+                                      ...); /* null terminated */
+
+/**
+ * @brief Serialize a PINGREQ and put it into \p buf.
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to put the PINGREQ packet in.
+ * @param[in] bufsz the maximum number of bytes that can be put into \p buf.
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718081">
+ * MQTT v3.1.1: PINGREQ - Ping Request.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the PINGREQ
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_ping_request(uint8_t *buf, size_t bufsz);
+
+/**
+ * @brief Serialize a DISCONNECT and put it into \p buf.
+ * @ingroup packers
+ * 
+ * @param[out] buf the buffer to put the DISCONNECT packet in.
+ * @param[in] bufsz the maximum number of bytes that can be put into \p buf.
+ * 
+ * @see <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718090">
+ * MQTT v3.1.1: DISCONNECT - Disconnect Notification.
+ * </a>
+ * 
+ * @returns The number of bytes put into \p buf, 0 if \p buf is too small to fit the DISCONNECT 
+ *          packet, a negative value if there was a protocol violation.
+ */
+ssize_t mqtt_pack_disconnect(uint8_t *buf, size_t bufsz);
+
+
+/**
+ * @brief An enumeration of queued message states. 
+ * @ingroup details
+ */
+enum MQTTQueuedMessageState {
+    MQTT_QUEUED_UNSENT,
+    MQTT_QUEUED_AWAITING_ACK,
+    MQTT_QUEUED_COMPLETE
+};
+
+/**
+ * @brief A message in a mqtt_message_queue.
+ * @ingroup details
+ */
+struct mqtt_queued_message {
+    /** @brief A pointer to the start of the message. */
+    uint8_t *start;
+
+    /** @brief The number of bytes in the message. */
+    size_t size;
+
+
+    /** @brief The state of the message. */
+    enum MQTTQueuedMessageState state;
+
+    /** 
+     * @brief The time at which the message was sent..
+     * 
+     * @note A timeout will only occur if the message is in
+     *       the MQTT_QUEUED_AWAITING_ACK \c state.
+     */
+    mqtt_pal_time_t time_sent;
+
+    /**
+     * @brief The control type of the message.
+     */
+    enum MQTTControlPacketType control_type;
+
+    /** 
+     * @brief The packet id of the message.
+     * 
+     * @note This field is only used if the associate \c control_type has a 
+     *       \c packet_id field.
+     */
+    uint16_t packet_id;
+};
+
+/**
+ * @brief A message queue.
+ * @ingroup details
+ * 
+ * @note This struct is used internally to manage sending messages.
+ * @note The only members the user should use are \c curr and \c curr_sz. 
+ */
+struct mqtt_message_queue {
+    /** 
+     * @brief The start of the message queue's memory block. 
+     * 
+     * @warning This member should \em not be manually changed.
+     */
+    void *mem_start;
+
+    /** @brief The end of the message queue's memory block. */
+    void *mem_end;
+
+    /**
+     * @brief A pointer to the position in the buffer you can pack bytes at.
+     * 
+     * @note Immediately after packing bytes at \c curr you \em must call
+     *       mqtt_mq_register.
+     */
+    uint8_t *curr;
+
+    /**
+     * @brief The number of bytes that can be written to \c curr.
+     * 
+     * @note curr_sz will decrease by more than the number of bytes you write to 
+     *       \c curr. This is because the mqtt_queued_message structs share the 
+     *       same memory (and thus, a mqtt_queued_message must be allocated in 
+     *       the message queue's memory whenever a new message is registered).  
+     */
+    size_t curr_sz;
+    
+    /**
+     * @brief The tail of the array of mqtt_queued_messages's.
+     * 
+     * @note This member should not be used manually.
+     */
+    struct mqtt_queued_message *queue_tail;
+};
+
+/**
+ * @brief Initialize a message queue.
+ * @ingroup details
+ * 
+ * @param[out] mq The message queue to initialize.
+ * @param[in] buf The buffer for this message queue.
+ * @param[in] bufsz The number of bytes in the buffer. 
+ * 
+ * @relates mqtt_message_queue
+ */
+void mqtt_mq_init(struct mqtt_message_queue *mq, void *buf, size_t bufsz);
+
+/**
+ * @brief Clear as many messages from the front of the queue as possible.
+ * @ingroup details
+ * 
+ * @note Calls to this function are the \em only way to remove messages from the queue.
+ * 
+ * @param mq The message queue.
+ * 
+ * @relates mqtt_message_queue
+ */
+void mqtt_mq_clean(struct mqtt_message_queue *mq);
+
+/**
+ * @brief Register a message that was just added to the buffer.
+ * @ingroup details
+ * 
+ * @note This function should be called immediately following a call to a packer function
+ *       that returned a positive value. The positive value (number of bytes packed) should
+ *       be passed to this function.
+ * 
+ * @param mq The message queue.
+ * @param[in] nbytes The number of bytes that were just packed.
+ * 
+ * @note This function will step mqtt_message_queue::curr and update mqtt_message_queue::curr_sz.
+ * @relates mqtt_message_queue
+ * 
+ * @returns The newly added struct mqtt_queued_message.
+ */
+struct mqtt_queued_message* mqtt_mq_register(struct mqtt_message_queue *mq, size_t nbytes);
+
+/**
+ * @brief Find a message in the message queue.
+ * @ingroup details
+ * 
+ * @param mq The message queue.
+ * @param[in] control_type The control type of the message you want to find.
+ * @param[in] packet_id The packet ID of the message you want to find. Set to \c NULL if you 
+ *            don't want to specify a packet ID.
+ * 
+ * @relates mqtt_message_queue
+ * @returns The found message. \c NULL if the message was not found.
+ */
+struct mqtt_queued_message* mqtt_mq_find(struct mqtt_message_queue *mq, enum MQTTControlPacketType control_type, uint16_t *packet_id);
+
+/**
+ * @brief Returns the mqtt_queued_message at \p index.
+ * @ingroup details
+ * 
+ * @param mq_ptr A pointer to the message queue.
+ * @param index The index of the message. 
+ *
+ * @returns The mqtt_queued_message at \p index.
+ */
+#define mqtt_mq_get(mq_ptr, index) (((struct mqtt_queued_message*) ((mq_ptr)->mem_end)) - 1 - index)
+
+/**
+ * @brief Returns the number of messages in the message queue, \p mq_ptr.
+ * @ingroup details
+ */
+#define mqtt_mq_length(mq_ptr) (((struct mqtt_queued_message*) ((mq_ptr)->mem_end)) - (mq_ptr)->queue_tail)
+
+/**
+ * @brief Used internally to recalculate the \c curr_sz.
+ * @ingroup details
+ */
+#define mqtt_mq_currsz(mq_ptr) (mq_ptr->curr >= (uint8_t*) ((mq_ptr)->queue_tail - 1)) ? 0 : ((uint8_t*) ((mq_ptr)->queue_tail - 1)) - (mq_ptr)->curr
+
+/* CLIENT */
+
+/**
+ * @brief An MQTT client. 
+ * @ingroup details
+ * 
+ * @note All members can be manipulated via the related functions.
+ */
+struct mqtt_client {
+    /** @brief The socket connecting to the MQTT broker. */
+    mqtt_pal_socket_handle socketfd;
+
+    /** @brief The LFSR state used to generate packet ID's. */
+    uint16_t pid_lfsr;
+
+    /** @brief The keep-alive time in seconds. */
+    uint16_t keep_alive;
+
+    /** 
+     * @brief A counter counting pings that have been sent to keep the connection alive. 
+     * @see keep_alive
+     */
+    int number_of_keep_alives;
+
+    /**
+     * @brief The current sent offset.
+     *
+     * This is used to allow partial send commands.
+     */
+    size_t send_offset;
+
+    /** 
+     * @brief The timestamp of the last message sent to the buffer.
+     * 
+     * This is used to detect the need for keep-alive pings.
+     * 
+     * @see keep_alive
+    */
+    mqtt_pal_time_t time_of_last_send;
+
+    /** 
+     * @brief The error state of the client. 
+     * 
+     * error should be MQTT_OK for the entirety of the connection.
+     * 
+     * @note The error state will be MQTT_ERROR_CONNECT_NOT_CALLED until
+     *       you call mqtt_connect.
+     */
+    enum MQTTErrors error;
+
+    /** 
+     * @brief The timeout period in seconds.
+     * 
+     * If the broker doesn't return an ACK within response_timeout seconds a timeout
+     * will occur and the message will be retransmitted. 
+     * 
+     * @note The default value is 30 [seconds] but you can change it at any time.
+     */
+    int response_timeout;
+
+    /** @brief A counter counting the number of timeouts that have occurred. */
+    int number_of_timeouts;
+
+    /**
+     * @brief Approximately much time it has typically taken to receive responses from the 
+     *        broker.
+     * 
+     * @note This is tracked using a exponential-averaging.
+     */
+    double typical_response_time;
+
+    /**
+     * @brief The callback that is called whenever a publish is received from the broker.
+     * 
+     * Any topics that you have subscribed to will be returned from the broker as 
+     * mqtt_response_publish messages. All the publishes received from the broker will 
+     * be passed to this function.
+     * 
+     * @note A pointer to publish_response_callback_state is always passed to the callback.
+     *       Use publish_response_callback_state to keep track of any state information you 
+     *       need.
+     */
+    void (*publish_response_callback)(void** state, struct mqtt_response_publish *publish);
+
+    /**
+     * @brief A pointer to any publish_response_callback state information you need.
+     * 
+     * @note A pointer to this pointer will always be publish_response_callback upon 
+     *       receiving a publish message from the broker.
+     */
+    void* publish_response_callback_state;
+
+    /**
+     * @brief A user-specified callback, triggered on each \ref mqtt_sync, allowing
+     *        the user to perform state inspections (and custom socket error detection)
+     *        on the client.
+     * 
+     * This callback is triggered on each call to \ref mqtt_sync. If it returns MQTT_OK
+     * then \ref mqtt_sync will continue normally (performing reads and writes). If it
+     * returns an error then \ref mqtt_sync will not call reads and writes.
+     * 
+     * This callback can be used to perform custom error detection, namely platform
+     * specific socket error detection, and force the client into an error state.
+     * 
+     * This member is always initialized to NULL but it can be manually set at any 
+     * time.
+     */
+    enum MQTTErrors (*inspector_callback)(struct mqtt_client*);
+
+    /**
+     * @brief A callback that is called whenever the client is in an error state.
+     * 
+     * This callback is responsible for: application level error handling, closing
+     * previous sockets, and reestabilishing the connection to the broker and 
+     * session configurations (i.e. subscriptions).  
+     */
+    void (*reconnect_callback)(struct mqtt_client*, void**);
+
+    /**
+     * @brief A pointer to some state. A pointer to this member is passed to 
+     *        \ref mqtt_client.reconnect_callback.
+     */
+    void* reconnect_state;
+
+    /**
+     * @brief The buffer where ingress data is temporarily stored.
+     */
+    struct {
+        /** @brief The start of the receive buffer's memory. */
+        uint8_t *mem_start;
+
+        /** @brief The size of the receive buffer's memory. */
+        size_t mem_size;
+
+        /** @brief A pointer to the next writtable location in the receive buffer. */
+        uint8_t *curr;
+
+        /** @brief The number of bytes that are still writable at curr. */
+        size_t curr_sz;
+    } recv_buffer;
+
+    /** 
+     * @brief A variable passed to support thread-safety.
+     * 
+     * A pointer to this variable is passed to \c MQTT_PAL_MUTEX_LOCK, and
+     * \c MQTT_PAL_MUTEX_UNLOCK.
+     */
+    mqtt_pal_mutex_t mutex;
+
+    /** @brief The sending message queue. */
+    struct mqtt_message_queue mq;
+};
+
+/**
+ * @brief Generate a new next packet ID.
+ * @ingroup details
+ * 
+ * Packet ID's are generated using a max-length LFSR.
+ * 
+ * @param client The MQTT client.
+ * 
+ * @returns The new packet ID that should be used.
+ */
+uint16_t __mqtt_next_pid(struct mqtt_client *client);
+
+/**
+ * @brief Handles egress client traffic.
+ * @ingroup details
+ * 
+ * @param client The MQTT client.
+ * 
+ * @returns MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+ssize_t __mqtt_send(struct mqtt_client *client);
+
+/**
+ * @brief Handles ingress client traffic.
+ * @ingroup details
+ * 
+ * @param client The MQTT client.
+ * 
+ * @returns MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+ssize_t __mqtt_recv(struct mqtt_client *client);
+
+/**
+ * @brief Function that does the actual sending and receiving of 
+ *        traffic from the network.
+ * @ingroup api
+ * 
+ * All the other functions in the @ref api simply stage messages for
+ * being sent to the broker. This function does the actual sending of
+ * those messages. Additionally this function receives traffic (responses and 
+ * acknowledgements) from the broker and responds to that traffic accordingly.
+ * Lastly this function also calls the \c publish_response_callback when
+ * any \c MQTT_CONTROL_PUBLISH messages are received.
+ * 
+ * @pre mqtt_init must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * 
+ * @attention It is the responsibility of the application programmer to 
+ *            call this function periodically. All functions in the @ref api are
+ *            thread-safe so it is perfectly reasonable to have a thread dedicated
+ *            to calling this function every 200 ms or so. MQTT-C can be used in single
+ *            threaded application though by simply calling this functino periodically 
+ *            inside your main thread. See @ref simple_publisher.c and @ref simple_subscriber.c
+ *            for examples (specifically the \c client_refresher functions).
+ * 
+ * @returns MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+enum MQTTErrors mqtt_sync(struct mqtt_client *client);
+
+/**
+ * @brief Initializes an MQTT client.
+ * @ingroup api
+ * 
+ * This function \em must be called before any other API function calls.
+ * 
+ * @pre None.
+ * 
+ * @param[out] client The MQTT client.
+ * @param[in] sockfd The socket file descriptor (or equivalent socket handle, e.g. BIO pointer 
+ *            for OpenSSL sockets) connected to the MQTT broker.
+ * @param[in] sendbuf A buffer that will be used for sending messages to the broker.
+ * @param[in] sendbufsz The size of \p sendbuf in bytes.
+ * @param[in] recvbuf A buffer that will be used for receiving messages from the broker.
+ * @param[in] recvbufsz The size of \p recvbuf in bytes.
+ * @param[in] publish_response_callback The callback to call whenever application messages
+ *            are received from the broker. 
+ * 
+ * @post mqtt_connect must be called.
+ * 
+ * @note \p sockfd is a non-blocking TCP connection.
+ * @note If \p sendbuf fills up completely during runtime a \c MQTT_ERROR_SEND_BUFFER_IS_FULL
+ *       error will be set. Similarly if \p recvbuf is ever to small to receive a message from
+ *       the broker an MQTT_ERROR_RECV_BUFFER_TOO_SMALL error will be set.
+ * @note A pointer to \ref mqtt_client.publish_response_callback_state is always passed as the 
+ *       \c state argument to \p publish_response_callback. Note that the second argument is 
+ *       the mqtt_response_publish that was received from the broker.
+ * 
+ * @attention Only initialize an MQTT client once (i.e. don't call \ref mqtt_init or 
+ *            \ref mqtt_init_reconnect more than once per client).
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise.
+ */
+enum MQTTErrors mqtt_init(struct mqtt_client *client,
+                          mqtt_pal_socket_handle sockfd,
+                          uint8_t *sendbuf, size_t sendbufsz,
+                          uint8_t *recvbuf, size_t recvbufsz,
+                          void (*publish_response_callback)(void** state, struct mqtt_response_publish *publish));
+
+/**
+ * @brief Initializes an MQTT client and enables automatic reconnections.
+ * @ingroup api
+ * 
+ * An alternative to \ref mqtt_init that allows the client to automatically reconnect to the 
+ * broker after an error occurs (e.g. socket error or internal buffer overflows).
+ * 
+ * This is accomplished by calling the \p reconnect_callback whenever the client enters an error 
+ * state. The job of the \p reconnect_callback is to: (1) perform error handling/logging, 
+ * (2) clean up the old connection (i.e. close client->socketfd), (3) \ref mqtt_reinit the 
+ * client, and (4) reconfigure the MQTT session by calling \ref mqtt_connect followed by other 
+ * API calls such as \ref mqtt_subscribe.
+ * 
+ * The first argument to the \p reconnect_callback is the client (which will be in an error 
+ * state) and the second argument is a pointer to a void pointer where you can store some state
+ * information. Internally, MQTT-C calls the reconnect callback like so: 
+ * 
+ * \code 
+ *     client->reconnect_callback(client, &client->reconnect_state)
+ * \endcode
+ * 
+ * Note that the \p reconnect_callback is also called to setup the initial session. After
+ * calling \ref mqtt_init_reconnect the client will be in the error state 
+ * \c MQTT_ERROR_INITIAL_RECONNECT.
+ * 
+ * @pre None.
+ * 
+ * @param[in,out] client The MQTT client that will be initialized.
+ * @param[in] reconnect_callback The callback that will be called to connect/reconnect the 
+ *            client to the broker and perform application level error handling. 
+ * @param[in] reconnect_state A pointer to some state data for your \p reconnect_callback.
+ *            If your \p reconnect_callback does not require any state information set this
+ *            to NULL. A pointer to the memory address where the client stores a copy of this
+ *            pointer is passed as the second argumnet to \p reconnect_callback. 
+ * @param[in] publish_response_callback The callback to call whenever application messages
+ *            are received from the broker. 
+ * 
+ * @post Call \p reconnect_callback yourself, or call \ref mqtt_sync 
+ *       (which will trigger the call to \p reconnect_callback).
+ * 
+ * @attention Only initialize an MQTT client once (i.e. don't call \ref mqtt_init or 
+ *            \ref mqtt_init_reconnect more than once per client).
+ *
+ */
+void mqtt_init_reconnect(struct mqtt_client *client,
+                         void (*reconnect_callback)(struct mqtt_client *client, void** state),
+                         void *reconnect_state,
+                         void (*publish_response_callback)(void** state, struct mqtt_response_publish *publish));
+
+/**
+ * @brief Safely assign/reassign a socket and buffers to an new/existing client.
+ * @ingroup api
+ * 
+ * This function also clears the \p client error state. Upon exiting this function
+ * \c client->error will be \c MQTT_ERROR_CONNECT_NOT_CALLED (which will be cleared)
+ * as soon as \ref mqtt_connect is called.
+ * 
+ * @pre This function must be called BEFORE \ref mqtt_connect. 
+ * 
+ * @param[in,out] client The MQTT client.
+ * @param[in] socketfd The new socket connected to the broker. 
+ * @param[in] sendbuf The buffer that will be used to buffer egress traffic to the broker.
+ * @param[in] sendbufsz The size of \p sendbuf in bytes.
+ * @param[in] recvbuf The buffer that will be used to buffer ingress traffic from the broker.
+ * @param[in] recvbufsz The size of \p recvbuf in bytes.
+ * 
+ * @post Call \ref mqtt_connect.
+ * 
+ * @attention This function should be used in conjunction with clients that have been 
+ *            initialzed with \ref mqtt_init_reconnect.  
+ */
+void mqtt_reinit(struct mqtt_client* client,
+                 mqtt_pal_socket_handle socketfd,
+                 uint8_t *sendbuf, size_t sendbufsz,
+                 uint8_t *recvbuf, size_t recvbufsz);
+
+/**
+ * @brief Establishes a session with the MQTT broker.
+ * @ingroup api
+ * 
+ * @pre mqtt_init must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * @param[in] client_id The unique name identifying the client. (or NULL)
+ * @param[in] will_topic The topic name of client's \p will_message. If no will message is 
+ *            desired set to \c NULL.
+ * @param[in] will_message The application message (data) to be published in the event the 
+ *            client ungracefully disconnects. Set to \c NULL if \p will_topic is \c NULL.
+ * @param[in] will_message_size The size of \p will_message in bytes.
+ * @param[in] user_name The username to use when establishing the session with the MQTT broker.
+ *            Set to \c NULL if a username is not required.
+ * @param[in] password The password to use when establishing the session with the MQTT broker.
+ *            Set to \c NULL if a password is not required.
+ * @param[in] connect_flags Additional \ref MQTTConnectFlags to use when establishing the connection. 
+ *            These flags are for forcing the session to start clean, 
+ *            \c MQTT_CONNECT_CLEAN_SESSION, the QOS level to publish the \p will_message with 
+ *            (provided \c will_message != \c NULL), MQTT_CONNECT_WILL_QOS_[0,1,2], and whether 
+ *            or not the broker should retain the \c will_message, MQTT_CONNECT_WILL_RETAIN.
+ * @param[in] keep_alive The keep-alive time in seconds. A reasonable value for this is 400 [seconds]. 
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise.
+ */
+enum MQTTErrors mqtt_connect(struct mqtt_client *client,
+                             const char* client_id,
+                             const char* will_topic,
+                             const void* will_message,
+                             size_t will_message_size,
+                             const char* user_name,
+                             const char* password,
+                             uint8_t connect_flags,
+                             uint16_t keep_alive);
+
+/* 
+    todo: will_message should be a void*
+*/
+
+/**
+ * @brief Publish an application message.
+ * @ingroup api
+ * 
+ * Publishes an application message to the MQTT broker.
+ * 
+ * @pre mqtt_connect must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * @param[in] topic_name The name of the topic.
+ * @param[in] application_message The data to be published.
+ * @param[in] application_message_size The size of \p application_message in bytes.
+ * @param[in] publish_flags \ref MQTTPublishFlags to be used, namely the QOS level to 
+ *            publish at (MQTT_PUBLISH_QOS_[0,1,2]) or whether or not the broker should 
+ *            retain the publish (MQTT_PUBLISH_RETAIN).
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise.
+ */
+enum MQTTErrors mqtt_publish(struct mqtt_client *client,
+                             const char* topic_name,
+                             void* application_message,
+                             size_t application_message_size,
+                             uint8_t publish_flags);
+
+/**
+ * @brief Acknowledge an ingree publish with QOS==1.
+ * @ingroup details
+ *
+ * @param[in,out] client The MQTT client.
+ * @param[in] packet_id The packet ID of the ingress publish being acknowledged.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+ssize_t __mqtt_puback(struct mqtt_client *client, uint16_t packet_id);
+
+/**
+ * @brief Acknowledge an ingree publish with QOS==2.
+ * @ingroup details
+ *
+ * @param[in,out] client The MQTT client.
+ * @param[in] packet_id The packet ID of the ingress publish being acknowledged.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+ssize_t __mqtt_pubrec(struct mqtt_client *client, uint16_t packet_id);
+
+/**
+ * @brief Acknowledge an ingree PUBREC packet.
+ * @ingroup details
+ *
+ * @param[in,out] client The MQTT client.
+ * @param[in] packet_id The packet ID of the ingress PUBREC being acknowledged.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+ssize_t __mqtt_pubrel(struct mqtt_client *client, uint16_t packet_id);
+
+/**
+ * @brief Acknowledge an ingree PUBREL packet.
+ * @ingroup details
+ *
+ * @param[in,out] client The MQTT client.
+ * @param[in] packet_id The packet ID of the ingress PUBREL being acknowledged.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+ssize_t __mqtt_pubcomp(struct mqtt_client *client, uint16_t packet_id);
+
+
+/**
+ * @brief Subscribe to a topic.
+ * @ingroup api
+ * 
+ * @pre mqtt_connect must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * @param[in] topic_name The name of the topic to subscribe to.
+ * @param[in] max_qos_level The maximum QOS level with which the broker can send application
+ *            messages for this topic.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+enum MQTTErrors mqtt_subscribe(struct mqtt_client *client,
+                               const char* topic_name,
+                               int max_qos_level);
+
+/**
+ * @brief Unsubscribe from a topic.
+ * @ingroup api
+ * 
+ * @pre mqtt_connect must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * @param[in] topic_name The name of the topic to unsubscribe from.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise. 
+ */
+enum MQTTErrors mqtt_unsubscribe(struct mqtt_client *client,
+                                 const char* topic_name);
+
+/**
+ * @brief Ping the broker. 
+ * @ingroup api
+ * 
+ * @pre mqtt_connect must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise.
+ */
+enum MQTTErrors mqtt_ping(struct mqtt_client *client);
+
+/**
+ * @brief Ping the broker without locking/unlocking the mutex. 
+ * @see mqtt_ping
+ */
+enum MQTTErrors __mqtt_ping(struct mqtt_client *client);
+
+/**
+ * @brief Terminate the session with the MQTT broker. 
+ * @ingroup api
+ * 
+ * @pre mqtt_connect must have been called.
+ * 
+ * @param[in,out] client The MQTT client.
+ * 
+ * @note To re-establish the session, mqtt_connect must be called.
+ * 
+ * @returns \c MQTT_OK upon success, an \ref MQTTErrors otherwise.
+ */
+enum MQTTErrors mqtt_disconnect(struct mqtt_client *client);
+
+#endif

deps/MQTT-C/include/mqtt_pal.h

+#ifndef __MQTT_PAL_H__
+#define __MQTT_PAL_H__
+
+/*
+MIT License
+
+Copyright(c) 2018 Liam Bindle
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+/**
+ * @file
+ * @brief Includes/supports the types/calls required by the MQTT-C client.
+ * 
+ * @note This is the \em only file included in mqtt.h, and mqtt.c. It is therefore 
+ *       responsible for including/supporting all the required types and calls. 
+ * 
+ * @defgroup pal Platform abstraction layer
+ * @brief Documentation of the types and calls required to port MQTT-C to a new platform.
+ * 
+ * mqtt_pal.h is the \em only header file included in mqtt.c. Therefore, to port MQTT-C to a 
+ * new platform the following types, functions, constants, and macros must be defined in 
+ * mqtt_pal.h:
+ *  - Types:
+ *      - \c size_t, \c ssize_t
+ *      - \c uint8_t, \c uint16_t, \c uint32_t
+ *      - \c va_list
+ *      - \c mqtt_pal_time_t : return type of \c MQTT_PAL_TIME() 
+ *      - \c mqtt_pal_mutex_t : type of the argument that is passed to \c MQTT_PAL_MUTEX_LOCK and 
+ *        \c MQTT_PAL_MUTEX_RELEASE
+ *  - Functions:
+ *      - \c memcpy, \c strlen
+ *      - \c va_start, \c va_arg, \c va_end
+ *  - Constants:
+ *      - \c INT_MIN
+ * 
+ * Additionally, three macro's are required:
+ *  - \c MQTT_PAL_HTONS(s) : host-to-network endian conversion for uint16_t.
+ *  - \c MQTT_PAL_NTOHS(s) : network-to-host endian conversion for uint16_t.
+ *  - \c MQTT_PAL_TIME()   : returns [type: \c mqtt_pal_time_t] current time in seconds. 
+ *  - \c MQTT_PAL_MUTEX_LOCK(mtx_pointer) : macro that locks the mutex pointed to by \c mtx_pointer.
+ *  - \c MQTT_PAL_MUTEX_RELEASE(mtx_pointer) : macro that unlocks the mutex pointed to by 
+ *    \c mtx_pointer.
+ * 
+ * Lastly, \ref mqtt_pal_sendall and \ref mqtt_pal_recvall, must be implemented in mqtt_pal.c 
+ * for sending and receiving data using the platforms socket calls.
+ */
+
+
+/* UNIX-like platform support */
+#if defined(__unix__) || defined(__APPLE__)
+    #include <limits.h>
+    #include <string.h>
+    #include <stdarg.h>
+    #include <time.h>
+    #include <arpa/inet.h>
+    #include <pthread.h>
+
+    #define MQTT_PAL_HTONS(s) htons(s)
+    #define MQTT_PAL_NTOHS(s) ntohs(s)
+
+    #define MQTT_PAL_TIME() time(NULL)
+
+    typedef time_t mqtt_pal_time_t;
+    typedef pthread_mutex_t mqtt_pal_mutex_t;
+
+    #define MQTT_PAL_MUTEX_INIT(mtx_ptr) pthread_mutex_init(mtx_ptr, NULL)
+    #define MQTT_PAL_MUTEX_LOCK(mtx_ptr) pthread_mutex_lock(mtx_ptr)
+    #define MQTT_PAL_MUTEX_UNLOCK(mtx_ptr) pthread_mutex_unlock(mtx_ptr)
+
+    #ifndef MQTT_USE_CUSTOM_SOCKET_HANDLE
+        #ifdef MQTT_USE_MBEDTLS
+            struct mbedtls_ssl_context;
+            typedef struct mbedtls_ssl_context *mqtt_pal_socket_handle;
+        #elif defined(MQTT_USE_BIO)
+            #include <openssl/bio.h>
+            typedef BIO* mqtt_pal_socket_handle;
+        #else
+            typedef int mqtt_pal_socket_handle;
+        #endif
+    #endif
+#elif defined(_MSC_VER)
+    #include <limits.h>
+    #include <windows.h>
+    #include <time.h>
+    #include <stdint.h>
+    #include <winsock2.h>
+
+    typedef SSIZE_T ssize_t;
+    #define MQTT_PAL_HTONS(s) htons(s)
+    #define MQTT_PAL_NTOHS(s) ntohs(s)
+
+    #define MQTT_PAL_TIME() time(NULL)
+
+    typedef time_t mqtt_pal_time_t;
+    typedef CRITICAL_SECTION mqtt_pal_mutex_t;
+
+    #define MQTT_PAL_MUTEX_INIT(mtx_ptr) InitializeCriticalSection(mtx_ptr)
+    #define MQTT_PAL_MUTEX_LOCK(mtx_ptr) EnterCriticalSection(mtx_ptr)
+    #define MQTT_PAL_MUTEX_UNLOCK(mtx_ptr) LeaveCriticalSection(mtx_ptr)
+
+
+    #ifndef MQTT_USE_CUSTOM_SOCKET_HANDLE
+        #ifdef MQTT_USE_BIO
+            #include <openssl/bio.h>
+            typedef BIO* mqtt_pal_socket_handle;
+        #else
+            typedef SOCKET mqtt_pal_socket_handle;
+        #endif
+    #endif
+
+#endif
+
+/**
+ * @brief Sends all the bytes in a buffer.
+ * @ingroup pal
+ * 
+ * @param[in] fd The file-descriptor (or handle) of the socket.
+ * @param[in] buf A pointer to the first byte in the buffer to send.
+ * @param[in] len The number of bytes to send (starting at \p buf).
+ * @param[in] flags Flags which are passed to the underlying socket.
+ * 
+ * @returns The number of bytes sent if successful, an \ref MQTTErrors otherwise.
+ */
+ssize_t mqtt_pal_sendall(mqtt_pal_socket_handle fd, const void* buf, size_t len, int flags);
+
+/**
+ * @brief Non-blocking receive all the byte available.
+ * @ingroup pal
+ * 
+ * @param[in] fd The file-descriptor (or handle) of the socket.
+ * @param[in] buf A pointer to the receive buffer.
+ * @param[in] bufsz The max number of bytes that can be put into \p buf.
+ * @param[in] flags Flags which are passed to the underlying socket.
+ * 
+ * @returns The number of bytes received if successful, an \ref MQTTErrors otherwise.
+ */
+ssize_t mqtt_pal_recvall(mqtt_pal_socket_handle fd, void* buf, size_t bufsz, int flags);
+
+#endif

deps/MQTT-C/src/mqtt.c

+/*
+MIT License
+
+Copyright(c) 2018 Liam Bindle
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#include <mqtt.h>
+
+/** 
+ * @file 
+ * @brief Implements the functionality of MQTT-C.
+ * @note The only files that are included are mqtt.h and mqtt_pal.h.
+ * 
+ * @cond Doxygen_Suppress
+ */
+
+enum MQTTErrors mqtt_sync(struct mqtt_client *client) {
+    /* Recover from any errors */
+    enum MQTTErrors err;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+    if (client->error != MQTT_OK && client->reconnect_callback != NULL) {
+        client->reconnect_callback(client, &client->reconnect_state);
+        /* unlocked during CONNECT */
+    } else {
+        MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    }
+
+    /* Call inspector callback if necessary */
+    
+    if (client->inspector_callback != NULL) {
+        MQTT_PAL_MUTEX_LOCK(&client->mutex);
+        err = client->inspector_callback(client);
+        MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+        if (err != MQTT_OK) return err;
+    }
+
+    /* Call receive */
+    err = __mqtt_recv(client);
+    if (err != MQTT_OK) return err;
+
+    /* Call send */
+    err = __mqtt_send(client);
+    return err;
+}
+
+uint16_t __mqtt_next_pid(struct mqtt_client *client) {
+    int pid_exists = 0;
+    if (client->pid_lfsr == 0) {
+        client->pid_lfsr = 163u;
+    }
+    /* LFSR taps taken from: https://en.wikipedia.org/wiki/Linear-feedback_shift_register */
+    
+    do {
+        struct mqtt_queued_message *curr;
+        unsigned lsb = client->pid_lfsr & 1;
+        (client->pid_lfsr) >>= 1;
+        if (lsb) {
+            client->pid_lfsr ^= 0xB400u;
+        }
+
+        /* check that the PID is unique */
+        pid_exists = 0;
+        for(curr = mqtt_mq_get(&(client->mq), 0); curr >= client->mq.queue_tail; --curr) {
+            if (curr->packet_id == client->pid_lfsr) {
+                pid_exists = 1;
+                break;
+            }
+        }
+
+    } while(pid_exists);
+    return client->pid_lfsr;
+}
+
+enum MQTTErrors mqtt_init(struct mqtt_client *client,
+               mqtt_pal_socket_handle sockfd,
+               uint8_t *sendbuf, size_t sendbufsz,
+               uint8_t *recvbuf, size_t recvbufsz,
+               void (*publish_response_callback)(void** state,struct mqtt_response_publish *publish))
+{
+    if (client == NULL || sendbuf == NULL || recvbuf == NULL) {
+        return MQTT_ERROR_NULLPTR;
+    }
+
+    /* initialize mutex */
+    MQTT_PAL_MUTEX_INIT(&client->mutex);
+    MQTT_PAL_MUTEX_LOCK(&client->mutex); /* unlocked during CONNECT */
+
+    client->socketfd = sockfd;
+
+    mqtt_mq_init(&client->mq, sendbuf, sendbufsz);
+
+    client->recv_buffer.mem_start = recvbuf;
+    client->recv_buffer.mem_size = recvbufsz;
+    client->recv_buffer.curr = client->recv_buffer.mem_start;
+    client->recv_buffer.curr_sz = client->recv_buffer.mem_size;
+
+    client->error = MQTT_ERROR_CONNECT_NOT_CALLED;
+    client->response_timeout = 30;
+    client->number_of_timeouts = 0;
+    client->number_of_keep_alives = 0;
+    client->typical_response_time = -1.0;
+    client->publish_response_callback = publish_response_callback;
+    client->pid_lfsr = 0;
+    client->send_offset = 0;
+
+    client->inspector_callback = NULL;
+    client->reconnect_callback = NULL;
+    client->reconnect_state = NULL;
+
+    return MQTT_OK;
+}
+
+void mqtt_init_reconnect(struct mqtt_client *client,
+                         void (*reconnect)(struct mqtt_client *, void**),
+                         void *reconnect_state,
+                         void (*publish_response_callback)(void** state, struct mqtt_response_publish *publish))
+{
+    /* initialize mutex */
+    MQTT_PAL_MUTEX_INIT(&client->mutex);
+
+    client->socketfd = (mqtt_pal_socket_handle) -1;
+
+    mqtt_mq_init(&client->mq, NULL, 0);
+
+    client->recv_buffer.mem_start = NULL;
+    client->recv_buffer.mem_size = 0;
+    client->recv_buffer.curr = NULL;
+    client->recv_buffer.curr_sz = 0;
+
+    client->error = MQTT_ERROR_INITIAL_RECONNECT;
+    client->response_timeout = 30;
+    client->number_of_timeouts = 0;
+    client->number_of_keep_alives = 0;
+    client->typical_response_time = -1.0;
+    client->publish_response_callback = publish_response_callback;
+    client->send_offset = 0;
+
+    client->inspector_callback = NULL;
+    client->reconnect_callback = reconnect;
+    client->reconnect_state = reconnect_state;
+}
+
+void mqtt_reinit(struct mqtt_client* client,
+                 mqtt_pal_socket_handle socketfd,
+                 uint8_t *sendbuf, size_t sendbufsz,
+                 uint8_t *recvbuf, size_t recvbufsz)
+{
+    client->error = MQTT_ERROR_CONNECT_NOT_CALLED;
+    client->socketfd = socketfd;
+
+    mqtt_mq_init(&client->mq, sendbuf, sendbufsz);
+
+    client->recv_buffer.mem_start = recvbuf;
+    client->recv_buffer.mem_size = recvbufsz;
+    client->recv_buffer.curr = client->recv_buffer.mem_start;
+    client->recv_buffer.curr_sz = client->recv_buffer.mem_size;
+}
+
+/** 
+ * A macro function that:
+ *      1) Checks that the client isn't in an error state.
+ *      2) Attempts to pack to client's message queue.
+ *          a) handles errors
+ *          b) if mq buffer is too small, cleans it and tries again
+ *      3) Upon successful pack, registers the new message.
+ */
+#define MQTT_CLIENT_TRY_PACK(tmp, msg, client, pack_call, release)  \
+    if (client->error < 0) {                                        \
+        if (release) MQTT_PAL_MUTEX_UNLOCK(&client->mutex);         \
+        return client->error;                                       \
+    }                                                               \
+    tmp = pack_call;                                                \
+    if (tmp < 0) {                                                  \
+        client->error = tmp;                                        \
+        if (release) MQTT_PAL_MUTEX_UNLOCK(&client->mutex);         \
+        return tmp;                                                 \
+    } else if (tmp == 0) {                                          \
+        mqtt_mq_clean(&client->mq);                                 \
+        tmp = pack_call;                                            \
+        if (tmp < 0) {                                              \
+            client->error = tmp;                                    \
+            if (release) MQTT_PAL_MUTEX_UNLOCK(&client->mutex);     \
+            return tmp;                                             \
+        } else if(tmp == 0) {                                       \
+            client->error = MQTT_ERROR_SEND_BUFFER_IS_FULL;         \
+            if (release) MQTT_PAL_MUTEX_UNLOCK(&client->mutex);     \
+            return MQTT_ERROR_SEND_BUFFER_IS_FULL;                  \
+        }                                                           \
+    }                                                               \
+    msg = mqtt_mq_register(&client->mq, tmp);                       \
+
+
+enum MQTTErrors mqtt_connect(struct mqtt_client *client,
+                     const char* client_id,
+                     const char* will_topic,
+                     const void* will_message,
+                     size_t will_message_size,
+                     const char* user_name,
+                     const char* password,
+                     uint8_t connect_flags,
+                     uint16_t keep_alive)
+{
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+
+    /* Note: Current thread already has mutex locked. */
+
+    /* update the client's state */
+    client->keep_alive = keep_alive;
+    if (client->error == MQTT_ERROR_CONNECT_NOT_CALLED) {
+        client->error = MQTT_OK;
+    }
+    
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(rv, msg, client, 
+        mqtt_pack_connection_request(
+            client->mq.curr, client->mq.curr_sz,
+            client_id, will_topic, will_message, 
+            will_message_size,user_name, password, 
+            connect_flags, keep_alive
+        ), 
+        1
+    );
+    /* save the control type of the message */
+    msg->control_type = MQTT_CONTROL_CONNECT;
+
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return MQTT_OK;
+}
+
+enum MQTTErrors mqtt_publish(struct mqtt_client *client,
+                     const char* topic_name,
+                     void* application_message,
+                     size_t application_message_size,
+                     uint8_t publish_flags)
+{
+    struct mqtt_queued_message *msg;
+    ssize_t rv;
+    uint16_t packet_id;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+    packet_id = __mqtt_next_pid(client);
+
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_publish_request(
+            client->mq.curr, client->mq.curr_sz,
+            topic_name,
+            packet_id,
+            application_message,
+            application_message_size,
+            publish_flags
+        ), 
+        1
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_PUBLISH;
+    msg->packet_id = packet_id;
+
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return MQTT_OK;
+}
+
+ssize_t __mqtt_puback(struct mqtt_client *client, uint16_t packet_id) {
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_pubxxx_request(
+            client->mq.curr, client->mq.curr_sz,
+            MQTT_CONTROL_PUBACK,
+            packet_id
+        ),
+        0
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_PUBACK;
+    msg->packet_id = packet_id;
+
+    return MQTT_OK;
+}
+
+ssize_t __mqtt_pubrec(struct mqtt_client *client, uint16_t packet_id) {
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_pubxxx_request(
+            client->mq.curr, client->mq.curr_sz,
+            MQTT_CONTROL_PUBREC,
+            packet_id
+        ),
+        0
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_PUBREC;
+    msg->packet_id = packet_id;
+
+    return MQTT_OK;
+}
+
+ssize_t __mqtt_pubrel(struct mqtt_client *client, uint16_t packet_id) {
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_pubxxx_request(
+            client->mq.curr, client->mq.curr_sz,
+            MQTT_CONTROL_PUBREL,
+            packet_id
+        ),
+        0
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_PUBREL;
+    msg->packet_id = packet_id;
+
+    return MQTT_OK;
+}
+
+ssize_t __mqtt_pubcomp(struct mqtt_client *client, uint16_t packet_id) {
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_pubxxx_request(
+            client->mq.curr, client->mq.curr_sz,
+            MQTT_CONTROL_PUBCOMP,
+            packet_id
+        ),
+        0
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_PUBCOMP;
+    msg->packet_id = packet_id;
+
+    return MQTT_OK;
+}
+
+enum MQTTErrors mqtt_subscribe(struct mqtt_client *client,
+                       const char* topic_name,
+                       int max_qos_level)
+{
+    ssize_t rv;
+    uint16_t packet_id;
+    struct mqtt_queued_message *msg;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+    packet_id = __mqtt_next_pid(client);
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_subscribe_request(
+            client->mq.curr, client->mq.curr_sz,
+            packet_id,
+            topic_name,
+            max_qos_level,
+            (const char*)NULL
+        ), 
+        1
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_SUBSCRIBE;
+    msg->packet_id = packet_id;
+
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return MQTT_OK;
+}
+
+enum MQTTErrors mqtt_unsubscribe(struct mqtt_client *client,
+                         const char* topic_name)
+{
+    uint16_t packet_id = __mqtt_next_pid(client);
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_unsubscribe_request(
+            client->mq.curr, client->mq.curr_sz,
+            packet_id,
+            topic_name,
+            (const char*)NULL
+        ), 
+        1
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_UNSUBSCRIBE;
+    msg->packet_id = packet_id;
+
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return MQTT_OK;
+}
+
+enum MQTTErrors mqtt_ping(struct mqtt_client *client) {
+    enum MQTTErrors rv;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+    rv = __mqtt_ping(client);
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return rv;
+}
+
+enum MQTTErrors __mqtt_ping(struct mqtt_client *client) 
+{
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_ping_request(
+            client->mq.curr, client->mq.curr_sz
+        ),
+        0
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_PINGREQ;
+
+    
+    return MQTT_OK;
+}
+
+enum MQTTErrors mqtt_disconnect(struct mqtt_client *client) 
+{
+    ssize_t rv;
+    struct mqtt_queued_message *msg;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+
+    /* try to pack the message */
+    MQTT_CLIENT_TRY_PACK(
+        rv, msg, client, 
+        mqtt_pack_disconnect(
+            client->mq.curr, client->mq.curr_sz
+        ), 
+        1
+    );
+    /* save the control type and packet id of the message */
+    msg->control_type = MQTT_CONTROL_DISCONNECT;
+
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return MQTT_OK;
+}
+
+ssize_t __mqtt_send(struct mqtt_client *client) 
+{
+    uint8_t inspected;
+    ssize_t len;
+    int inflight_qos2 = 0;
+    int i = 0;
+    
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+    
+    if (client->error < 0 && client->error != MQTT_ERROR_SEND_BUFFER_IS_FULL) {
+        MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+        return client->error;
+    }
+
+    /* loop through all messages in the queue */
+    len = mqtt_mq_length(&client->mq);
+    for(; i < len; ++i) {
+        struct mqtt_queued_message *msg = mqtt_mq_get(&client->mq, i);
+        int resend = 0;
+        if (msg->state == MQTT_QUEUED_UNSENT) {
+            /* message has not been sent to lets send it */
+            resend = 1;
+        } else if (msg->state == MQTT_QUEUED_AWAITING_ACK) {
+            /* check for timeout */
+            if (MQTT_PAL_TIME() > msg->time_sent + client->response_timeout) {
+                resend = 1;
+                client->number_of_timeouts += 1;
+                client->send_offset = 0;
+            }
+        }
+
+        /* only send QoS 2 message if there are no inflight QoS 2 PUBLISH messages */
+        if (msg->control_type == MQTT_CONTROL_PUBLISH
+            && (msg->state == MQTT_QUEUED_UNSENT || msg->state == MQTT_QUEUED_AWAITING_ACK)) 
+        {
+            inspected = 0x03 & ((msg->start[0]) >> 1); /* qos */
+            if (inspected == 2) {
+                if (inflight_qos2) {
+                    resend = 0;
+                }
+                inflight_qos2 = 1;
+            }
+        }
+
+        /* goto next message if we don't need to send */
+        if (!resend) {
+            continue;
+        }
+
+        /* we're sending the message */
+        {
+          ssize_t tmp = mqtt_pal_sendall(client->socketfd, msg->start + client->send_offset, msg->size - client->send_offset, 0);
+          if (tmp < 0) {
+            client->error = tmp;
+            MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+            return tmp;
+          } else {
+            client->send_offset += tmp;
+            if(client->send_offset < msg->size) {
+              /* partial sent. Await additional calls */
+              break;
+            } else {
+              /* whole message has been sent */
+              client->send_offset = 0;
+            }
+
+          }
+
+        }
+
+        /* update timeout watcher */
+        client->time_of_last_send = MQTT_PAL_TIME();
+        msg->time_sent = client->time_of_last_send;
+
+        /* 
+        Determine the state to put the message in.
+        Control Types:
+        MQTT_CONTROL_CONNECT     -> awaiting
+        MQTT_CONTROL_CONNACK     -> n/a
+        MQTT_CONTROL_PUBLISH     -> qos == 0 ? complete : awaiting
+        MQTT_CONTROL_PUBACK      -> complete
+        MQTT_CONTROL_PUBREC      -> awaiting
+        MQTT_CONTROL_PUBREL      -> awaiting
+        MQTT_CONTROL_PUBCOMP     -> complete
+        MQTT_CONTROL_SUBSCRIBE   -> awaiting
+        MQTT_CONTROL_SUBACK      -> n/a
+        MQTT_CONTROL_UNSUBSCRIBE -> awaiting
+        MQTT_CONTROL_UNSUBACK    -> n/a
+        MQTT_CONTROL_PINGREQ     -> awaiting
+        MQTT_CONTROL_PINGRESP    -> n/a
+        MQTT_CONTROL_DISCONNECT  -> complete
+        */
+        switch (msg->control_type) {
+        case MQTT_CONTROL_PUBACK:
+        case MQTT_CONTROL_PUBCOMP:
+        case MQTT_CONTROL_DISCONNECT:
+            msg->state = MQTT_QUEUED_COMPLETE;
+            break;
+        case MQTT_CONTROL_PUBLISH:
+            inspected = ( MQTT_PUBLISH_QOS_MASK & (msg->start[0]) ) >> 1; /* qos */
+            if (inspected == 0) {
+                msg->state = MQTT_QUEUED_COMPLETE;
+            } else if (inspected == 1) {
+                msg->state = MQTT_QUEUED_AWAITING_ACK;
+                /*set DUP flag for subsequent sends [Spec MQTT-3.3.1-1] */ 
+                msg->start[0] |= MQTT_PUBLISH_DUP;
+            } else {
+                msg->state = MQTT_QUEUED_AWAITING_ACK;
+            }
+            break;
+        case MQTT_CONTROL_CONNECT:
+        case MQTT_CONTROL_PUBREC:
+        case MQTT_CONTROL_PUBREL:
+        case MQTT_CONTROL_SUBSCRIBE:
+        case MQTT_CONTROL_UNSUBSCRIBE:
+        case MQTT_CONTROL_PINGREQ:
+            msg->state = MQTT_QUEUED_AWAITING_ACK;
+            break;
+        default:
+            client->error = MQTT_ERROR_MALFORMED_REQUEST;
+            MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+            return MQTT_ERROR_MALFORMED_REQUEST;
+        }
+    }
+
+    /* check for keep-alive */
+    {
+        mqtt_pal_time_t keep_alive_timeout = client->time_of_last_send + (mqtt_pal_time_t)((float)(client->keep_alive) * 0.75);
+        if (MQTT_PAL_TIME() > keep_alive_timeout) {
+          ssize_t rv = __mqtt_ping(client);
+          if (rv != MQTT_OK) {
+            client->error = rv;
+            MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+            return rv;
+          }
+        }
+    }
+
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return MQTT_OK;
+}
+
+ssize_t __mqtt_recv(struct mqtt_client *client)
+{
+    struct mqtt_response response;
+    ssize_t mqtt_recv_ret = MQTT_OK;
+    MQTT_PAL_MUTEX_LOCK(&client->mutex);
+
+    /* read until there is nothing left to read, or there was an error */
+    while(mqtt_recv_ret == MQTT_OK) {
+        /* read in as many bytes as possible */
+        ssize_t rv, consumed;
+        struct mqtt_queued_message *msg = NULL;
+
+        rv = mqtt_pal_recvall(client->socketfd, client->recv_buffer.curr, client->recv_buffer.curr_sz, 0);
+        if (rv < 0) {
+            /* an error occurred */
+            client->error = rv;
+            MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+            return rv;
+        } else {
+            client->recv_buffer.curr += rv;
+            client->recv_buffer.curr_sz -= rv;
+        }
+
+        /* attempt to parse */
+        consumed = mqtt_unpack_response(&response, client->recv_buffer.mem_start, client->recv_buffer.curr - client->recv_buffer.mem_start);
+
+        if (consumed < 0) {
+            client->error = consumed;
+            MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+            return consumed;
+        } else if (consumed == 0) {
+            /* if curr_sz is 0 then the buffer is too small to ever fit the message */
+            if (client->recv_buffer.curr_sz == 0) {
+                client->error = MQTT_ERROR_RECV_BUFFER_TOO_SMALL;
+                MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+                return MQTT_ERROR_RECV_BUFFER_TOO_SMALL;
+            }
+
+            /* just need to wait for the rest of the data */
+            MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+            return MQTT_OK;
+        }
+
+        /* response was unpacked successfully */
+
+        /*
+        The switch statement below manages how the client responds to messages from the broker.
+
+        Control Types (that we expect to receive from the broker):
+        MQTT_CONTROL_CONNACK:
+            -> release associated CONNECT
+            -> handle response
+        MQTT_CONTROL_PUBLISH:
+            -> stage response, none if qos==0, PUBACK if qos==1, PUBREC if qos==2
+            -> call publish callback
+        MQTT_CONTROL_PUBACK:
+            -> release associated PUBLISH
+        MQTT_CONTROL_PUBREC:
+            -> release PUBLISH
+            -> stage PUBREL
+        MQTT_CONTROL_PUBREL:
+            -> release associated PUBREC
+            -> stage PUBCOMP
+        MQTT_CONTROL_PUBCOMP:
+            -> release PUBREL
+        MQTT_CONTROL_SUBACK:
+            -> release SUBSCRIBE
+            -> handle response
+        MQTT_CONTROL_UNSUBACK:
+            -> release UNSUBSCRIBE
+        MQTT_CONTROL_PINGRESP:
+            -> release PINGREQ
+        */
+        switch (response.fixed_header.control_type) {
+            case MQTT_CONTROL_CONNACK:
+                /* release associated CONNECT */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_CONNECT, NULL);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* initialize typical response time */
+                client->typical_response_time = (double) (MQTT_PAL_TIME() - msg->time_sent);
+                /* check that connection was successful */
+                if (response.decoded.connack.return_code != MQTT_CONNACK_ACCEPTED) {
+                    if (response.decoded.connack.return_code == MQTT_CONNACK_REFUSED_IDENTIFIER_REJECTED) {
+                        client->error = MQTT_ERROR_CONNECT_CLIENT_ID_REFUSED;
+                        mqtt_recv_ret = MQTT_ERROR_CONNECT_CLIENT_ID_REFUSED;
+                    } else {
+                        client->error = MQTT_ERROR_CONNECTION_REFUSED;
+                        mqtt_recv_ret = MQTT_ERROR_CONNECTION_REFUSED;
+                    }
+                    break;
+                }
+                break;
+            case MQTT_CONTROL_PUBLISH:
+                /* stage response, none if qos==0, PUBACK if qos==1, PUBREC if qos==2 */
+                if (response.decoded.publish.qos_level == 1) {
+                    rv = __mqtt_puback(client, response.decoded.publish.packet_id);
+                    if (rv != MQTT_OK) {
+                        client->error = rv;
+                        mqtt_recv_ret = rv;
+                        break;
+                    }
+                } else if (response.decoded.publish.qos_level == 2) {
+                    /* check if this is a duplicate */
+                    if (mqtt_mq_find(&client->mq, MQTT_CONTROL_PUBREC, &response.decoded.publish.packet_id) != NULL) {
+                        break;
+                    }
+
+                    rv = __mqtt_pubrec(client, response.decoded.publish.packet_id);
+                    if (rv != MQTT_OK) {
+                        client->error = rv;
+                        mqtt_recv_ret = rv;
+                        break;
+                    }
+                }
+                /* call publish callback */
+                client->publish_response_callback(&client->publish_response_callback_state, &response.decoded.publish);
+                break;
+            case MQTT_CONTROL_PUBACK:
+                /* release associated PUBLISH */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_PUBLISH, &response.decoded.puback.packet_id);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                break;
+            case MQTT_CONTROL_PUBREC:
+                /* check if this is a duplicate */
+                if (mqtt_mq_find(&client->mq, MQTT_CONTROL_PUBREL, &response.decoded.pubrec.packet_id) != NULL) {
+                    break;
+                }
+                /* release associated PUBLISH */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_PUBLISH, &response.decoded.pubrec.packet_id);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                /* stage PUBREL */
+                rv = __mqtt_pubrel(client, response.decoded.pubrec.packet_id);
+                if (rv != MQTT_OK) {
+                    client->error = rv;
+                    mqtt_recv_ret = rv;
+                    break;
+                }
+                break;
+            case MQTT_CONTROL_PUBREL:
+                /* release associated PUBREC */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_PUBREC, &response.decoded.pubrel.packet_id);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                /* stage PUBCOMP */
+                rv = __mqtt_pubcomp(client, response.decoded.pubrec.packet_id);
+                if (rv != MQTT_OK) {
+                    client->error = rv;
+                    mqtt_recv_ret = rv;
+                    break;
+                }
+                break;
+            case MQTT_CONTROL_PUBCOMP:
+                /* release associated PUBREL */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_PUBREL, &response.decoded.pubcomp.packet_id);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                break;
+            case MQTT_CONTROL_SUBACK:
+                /* release associated SUBSCRIBE */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_SUBSCRIBE, &response.decoded.suback.packet_id);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                /* check that subscription was successful (not currently only one subscribe at a time) */
+                if (response.decoded.suback.return_codes[0] == MQTT_SUBACK_FAILURE) {
+                    client->error = MQTT_ERROR_SUBSCRIBE_FAILED;
+                    mqtt_recv_ret = MQTT_ERROR_SUBSCRIBE_FAILED;
+                    break;
+                }
+                break;
+            case MQTT_CONTROL_UNSUBACK:
+                /* release associated UNSUBSCRIBE */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_UNSUBSCRIBE, &response.decoded.unsuback.packet_id);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                break;
+            case MQTT_CONTROL_PINGRESP:
+                /* release associated PINGREQ */
+                msg = mqtt_mq_find(&client->mq, MQTT_CONTROL_PINGREQ, NULL);
+                if (msg == NULL) {
+                    client->error = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    mqtt_recv_ret = MQTT_ERROR_ACK_OF_UNKNOWN;
+                    break;
+                }
+                msg->state = MQTT_QUEUED_COMPLETE;
+                /* update response time */
+                client->typical_response_time = 0.875 * (client->typical_response_time) + 0.125 * (double) (MQTT_PAL_TIME() - msg->time_sent);
+                break;
+            default:
+                client->error = MQTT_ERROR_MALFORMED_RESPONSE;
+                mqtt_recv_ret = MQTT_ERROR_MALFORMED_RESPONSE;
+                break;
+        }
+        {
+          /* we've handled the response, now clean the buffer */
+          void* dest = (unsigned char*)client->recv_buffer.mem_start;
+          void* src  = (unsigned char*)client->recv_buffer.mem_start + consumed;
+          size_t n = client->recv_buffer.curr - client->recv_buffer.mem_start - consumed;
+          memmove(dest, src, n);
+          client->recv_buffer.curr -= consumed;
+          client->recv_buffer.curr_sz += consumed;
+        }
+    }
+
+    /* In case there was some error handling the (well formed) message, we end up here */
+    MQTT_PAL_MUTEX_UNLOCK(&client->mutex);
+    return mqtt_recv_ret;
+}
+
+/* FIXED HEADER */
+
+#define MQTT_BITFIELD_RULE_VIOLOATION(bitfield, rule_value, rule_mask) ((bitfield ^ rule_value) & rule_mask)
+
+struct {
+    const uint8_t control_type_is_valid[16];
+    const uint8_t required_flags[16];
+    const uint8_t mask_required_flags[16];
+} mqtt_fixed_header_rules = {
+    {   /* boolean value, true if type is valid */
+        0x00, /* MQTT_CONTROL_RESERVED */
+        0x01, /* MQTT_CONTROL_CONNECT */
+        0x01, /* MQTT_CONTROL_CONNACK */
+        0x01, /* MQTT_CONTROL_PUBLISH */
+        0x01, /* MQTT_CONTROL_PUBACK */
+        0x01, /* MQTT_CONTROL_PUBREC */
+        0x01, /* MQTT_CONTROL_PUBREL */
+        0x01, /* MQTT_CONTROL_PUBCOMP */
+        0x01, /* MQTT_CONTROL_SUBSCRIBE */
+        0x01, /* MQTT_CONTROL_SUBACK */
+        0x01, /* MQTT_CONTROL_UNSUBSCRIBE */
+        0x01, /* MQTT_CONTROL_UNSUBACK */
+        0x01, /* MQTT_CONTROL_PINGREQ */
+        0x01, /* MQTT_CONTROL_PINGRESP */
+        0x01, /* MQTT_CONTROL_DISCONNECT */
+        0x00  /* MQTT_CONTROL_RESERVED */
+    },
+    {   /* flags that must be set for the associated control type */
+        0x00, /* MQTT_CONTROL_RESERVED */
+        0x00, /* MQTT_CONTROL_CONNECT */
+        0x00, /* MQTT_CONTROL_CONNACK */
+        0x00, /* MQTT_CONTROL_PUBLISH */
+        0x00, /* MQTT_CONTROL_PUBACK */
+        0x00, /* MQTT_CONTROL_PUBREC */
+        0x02, /* MQTT_CONTROL_PUBREL */
+        0x00, /* MQTT_CONTROL_PUBCOMP */
+        0x02, /* MQTT_CONTROL_SUBSCRIBE */
+        0x00, /* MQTT_CONTROL_SUBACK */
+        0x02, /* MQTT_CONTROL_UNSUBSCRIBE */
+        0x00, /* MQTT_CONTROL_UNSUBACK */
+        0x00, /* MQTT_CONTROL_PINGREQ */
+        0x00, /* MQTT_CONTROL_PINGRESP */
+        0x00, /* MQTT_CONTROL_DISCONNECT */
+        0x00  /* MQTT_CONTROL_RESERVED */
+    },
+    {   /* mask of flags that must be specific values for the associated control type*/
+        0x00, /* MQTT_CONTROL_RESERVED */
+        0x0F, /* MQTT_CONTROL_CONNECT */
+        0x0F, /* MQTT_CONTROL_CONNACK */
+        0x00, /* MQTT_CONTROL_PUBLISH */
+        0x0F, /* MQTT_CONTROL_PUBACK */
+        0x0F, /* MQTT_CONTROL_PUBREC */
+        0x0F, /* MQTT_CONTROL_PUBREL */
+        0x0F, /* MQTT_CONTROL_PUBCOMP */
+        0x0F, /* MQTT_CONTROL_SUBSCRIBE */
+        0x0F, /* MQTT_CONTROL_SUBACK */
+        0x0F, /* MQTT_CONTROL_UNSUBSCRIBE */
+        0x0F, /* MQTT_CONTROL_UNSUBACK */
+        0x0F, /* MQTT_CONTROL_PINGREQ */
+        0x0F, /* MQTT_CONTROL_PINGRESP */
+        0x0F, /* MQTT_CONTROL_DISCONNECT */
+        0x00  /* MQTT_CONTROL_RESERVED */
+    }
+};
+
+static ssize_t mqtt_fixed_header_rule_violation(const struct mqtt_fixed_header *fixed_header) {
+    uint8_t control_type;
+    uint8_t control_flags;
+    uint8_t required_flags;
+    uint8_t mask_required_flags;
+
+    /* get value and rules */
+    control_type = fixed_header->control_type;
+    control_flags = fixed_header->control_flags;
+    required_flags = mqtt_fixed_header_rules.required_flags[control_type];
+    mask_required_flags = mqtt_fixed_header_rules.mask_required_flags[control_type];
+
+    /* check for valid type */
+    if (!mqtt_fixed_header_rules.control_type_is_valid[control_type]) {
+        return MQTT_ERROR_CONTROL_FORBIDDEN_TYPE;
+    }
+    
+    /* check that flags are appropriate */
+    if(MQTT_BITFIELD_RULE_VIOLOATION(control_flags, required_flags, mask_required_flags)) {
+        return MQTT_ERROR_CONTROL_INVALID_FLAGS;
+    }
+
+    return 0;
+}
+
+ssize_t mqtt_unpack_fixed_header(struct mqtt_response *response, const uint8_t *buf, size_t bufsz) {
+    struct mqtt_fixed_header *fixed_header;
+    const uint8_t *start = buf;
+    int lshift;
+    ssize_t errcode;
+    
+    /* check for null pointers or empty buffer */
+    if (response == NULL || buf == NULL) {
+        return MQTT_ERROR_NULLPTR;
+    }
+    fixed_header = &(response->fixed_header);
+
+    /* check that bufsz is not zero */
+    if (bufsz == 0) return 0;
+
+    /* parse control type and flags */
+    fixed_header->control_type  = *buf >> 4;
+    fixed_header->control_flags = *buf & 0x0F;
+
+    /* parse remaining size */
+    fixed_header->remaining_length = 0;
+
+    lshift = 0;
+    do {
+
+        /* MQTT spec (2.2.3) says the maximum length is 28 bits */
+        if(lshift == 28)
+            return MQTT_ERROR_INVALID_REMAINING_LENGTH;
+
+        /* consume byte and assert at least 1 byte left */
+        --bufsz;
+        ++buf;
+        if (bufsz == 0) return 0;
+
+        /* parse next byte*/
+        fixed_header->remaining_length += (*buf & 0x7F) << lshift;
+        lshift += 7;
+    } while(*buf & 0x80); /* while continue bit is set */ 
+
+    /* consume last byte */
+    --bufsz;
+    ++buf;
+
+    /* check that the fixed header is valid */
+    errcode = mqtt_fixed_header_rule_violation(fixed_header);
+    if (errcode) {
+        return errcode;
+    }
+
+    /* check that the buffer size if GT remaining length */
+    if (bufsz < fixed_header->remaining_length) {
+        return 0;
+    }
+
+    /* return how many bytes were consumed */
+    return buf - start;
+}
+
+ssize_t mqtt_pack_fixed_header(uint8_t *buf, size_t bufsz, const struct mqtt_fixed_header *fixed_header) {
+    const uint8_t *start = buf;
+    ssize_t errcode;
+    uint32_t remaining_length;
+    
+    /* check for null pointers or empty buffer */
+    if (fixed_header == NULL || buf == NULL) {
+        return MQTT_ERROR_NULLPTR;
+    }
+
+    /* check that the fixed header is valid */
+    errcode = mqtt_fixed_header_rule_violation(fixed_header);
+    if (errcode) {
+        return errcode;
+    }
+
+    /* check that bufsz is not zero */
+    if (bufsz == 0) return 0;
+
+    /* pack control type and flags */
+    *buf =  (((uint8_t) fixed_header->control_type) << 4) & 0xF0;
+    *buf |= ((uint8_t) fixed_header->control_flags)       & 0x0F;
+
+    remaining_length = fixed_header->remaining_length;
+
+    /* MQTT spec (2.2.3) says maximum remaining length is 2^28-1 */
+    if(remaining_length >= 256*1024*1024)
+        return MQTT_ERROR_INVALID_REMAINING_LENGTH;
+
+    do {
+        /* consume byte and assert at least 1 byte left */
+        --bufsz;
+        ++buf;
+        if (bufsz == 0) return 0;
+        
+        /* pack next byte */
+        *buf  = remaining_length & 0x7F;
+        if(remaining_length > 127) *buf |= 0x80;
+        remaining_length = remaining_length >> 7;
+    } while(*buf & 0x80);
+    
+    /* consume last byte */
+    --bufsz;
+    ++buf;
+
+    /* check that there's still enough space in buffer for packet */
+    if (bufsz < fixed_header->remaining_length) {
+        return 0;
+    }
+
+    /* return how many bytes were consumed */
+    return buf - start;
+}
+
+/* CONNECT */
+ssize_t mqtt_pack_connection_request(uint8_t* buf, size_t bufsz,
+                                     const char* client_id,
+                                     const char* will_topic,
+                                     const void* will_message,
+                                     size_t will_message_size,
+                                     const char* user_name,
+                                     const char* password,
+                                     uint8_t connect_flags,
+                                     uint16_t keep_alive)
+{ 
+    struct mqtt_fixed_header fixed_header;
+    size_t remaining_length;
+    const uint8_t *const start = buf;
+    ssize_t rv;
+
+    /* pack the fixed headr */
+    fixed_header.control_type = MQTT_CONTROL_CONNECT;
+    fixed_header.control_flags = 0x00;
+
+    /* calculate remaining length and build connect_flags at the same time */
+    connect_flags = connect_flags & ~MQTT_CONNECT_RESERVED;
+    remaining_length = 10; /* size of variable header */
+
+    if (client_id == NULL) {
+        client_id = "";
+    }
+    /* For an empty client_id, a clean session is required */
+    if (client_id[0] == '\0' && !(connect_flags & MQTT_CONNECT_CLEAN_SESSION)) {
+        return MQTT_ERROR_CLEAN_SESSION_IS_REQUIRED;
+    }
+    /* mqtt_string length is strlen + 2 */
+    remaining_length += __mqtt_packed_cstrlen(client_id);
+
+    if (will_topic != NULL) {
+        uint8_t temp;
+        /* there is a will */
+        connect_flags |= MQTT_CONNECT_WILL_FLAG;
+        remaining_length += __mqtt_packed_cstrlen(will_topic);
+        
+        if (will_message == NULL) {
+            /* if there's a will there MUST be a will message */
+            return MQTT_ERROR_CONNECT_NULL_WILL_MESSAGE;
+        }
+        remaining_length += 2 + will_message_size; /* size of will_message */
+
+        /* assert that the will QOS is valid (i.e. not 3) */
+        temp = connect_flags & 0x18; /* mask to QOS */   
+        if (temp == 0x18) {
+            /* bitwise equality with QoS 3 (invalid)*/
+            return MQTT_ERROR_CONNECT_FORBIDDEN_WILL_QOS;
+        }
+    } else {
+        /* there is no will so set all will flags to zero */
+        connect_flags &= ~MQTT_CONNECT_WILL_FLAG;
+        connect_flags &= ~0x18;
+        connect_flags &= ~MQTT_CONNECT_WILL_RETAIN;
+    }
+
+    if (user_name != NULL) {
+        /* a user name is present */
+        connect_flags |= MQTT_CONNECT_USER_NAME;
+        remaining_length += __mqtt_packed_cstrlen(user_name);
+    } else {
+        connect_flags &= ~MQTT_CONNECT_USER_NAME;
+    }
+
+    if (password != NULL) {
+        /* a password is present */
+        connect_flags |= MQTT_CONNECT_PASSWORD;
+        remaining_length += __mqtt_packed_cstrlen(password);
+    } else {
+        connect_flags &= ~MQTT_CONNECT_PASSWORD;
+    }
+
+    /* fixed header length is now calculated*/
+    fixed_header.remaining_length = remaining_length;
+
+    /* pack fixed header and perform error checks */
+    rv = mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+    if (rv <= 0) {
+        /* something went wrong */
+        return rv;
+    }
+    buf += rv;
+    bufsz -= rv;
+
+    /* check that the buffer has enough space to fit the remaining length */
+    if (bufsz < fixed_header.remaining_length) {
+        return 0;
+    }
+
+    /* pack the variable header */
+    *buf++ = 0x00;
+    *buf++ = 0x04;
+    *buf++ = (uint8_t) 'M';
+    *buf++ = (uint8_t) 'Q';
+    *buf++ = (uint8_t) 'T';
+    *buf++ = (uint8_t) 'T';
+    *buf++ = MQTT_PROTOCOL_LEVEL;
+    *buf++ = connect_flags;
+    buf += __mqtt_pack_uint16(buf, keep_alive);
+
+    /* pack the payload */
+    buf += __mqtt_pack_str(buf, client_id);
+    if (connect_flags & MQTT_CONNECT_WILL_FLAG) {
+        buf += __mqtt_pack_str(buf, will_topic);
+        buf += __mqtt_pack_uint16(buf, (uint16_t)will_message_size);
+        memcpy(buf, will_message, will_message_size);
+        buf += will_message_size;
+    }
+    if (connect_flags & MQTT_CONNECT_USER_NAME) {
+        buf += __mqtt_pack_str(buf, user_name);
+    }
+    if (connect_flags & MQTT_CONNECT_PASSWORD) {
+        buf += __mqtt_pack_str(buf, password);
+    }
+
+    /* return the number of bytes that were consumed */
+    return buf - start;
+}
+
+/* CONNACK */
+ssize_t mqtt_unpack_connack_response(struct mqtt_response *mqtt_response, const uint8_t *buf) {
+    const uint8_t *const start = buf;
+    struct mqtt_response_connack *response;
+
+    /* check that remaining length is 2 */
+    if (mqtt_response->fixed_header.remaining_length != 2) {
+        return MQTT_ERROR_MALFORMED_RESPONSE;
+    }
+    
+    response = &(mqtt_response->decoded.connack);
+    /* unpack */
+    if (*buf & 0xFE) {
+        /* only bit 1 can be set */
+        return MQTT_ERROR_CONNACK_FORBIDDEN_FLAGS;
+    } else {
+        response->session_present_flag = *buf++;
+    }
+
+    if (*buf > 5u) {
+        /* only bit 1 can be set */
+        return MQTT_ERROR_CONNACK_FORBIDDEN_CODE;
+    } else {
+        response->return_code = (enum MQTTConnackReturnCode) *buf++;
+    }
+    return buf - start;
+}
+
+/* DISCONNECT */
+ssize_t mqtt_pack_disconnect(uint8_t *buf, size_t bufsz) {
+    struct mqtt_fixed_header fixed_header;
+    fixed_header.control_type = MQTT_CONTROL_DISCONNECT;
+    fixed_header.control_flags = 0;
+    fixed_header.remaining_length = 0;
+    return mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+}
+
+/* PING */
+ssize_t mqtt_pack_ping_request(uint8_t *buf, size_t bufsz) {
+    struct mqtt_fixed_header fixed_header;
+    fixed_header.control_type = MQTT_CONTROL_PINGREQ;
+    fixed_header.control_flags = 0;
+    fixed_header.remaining_length = 0;
+    return mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+}
+
+/* PUBLISH */
+ssize_t mqtt_pack_publish_request(uint8_t *buf, size_t bufsz,
+                                  const char* topic_name,
+                                  uint16_t packet_id,
+                                  void* application_message,
+                                  size_t application_message_size,
+                                  uint8_t publish_flags)
+{
+    const uint8_t *const start = buf;
+    ssize_t rv;
+    struct mqtt_fixed_header fixed_header;
+    uint32_t remaining_length;
+    uint8_t inspected_qos;
+
+    /* check for null pointers */
+    if(buf == NULL || topic_name == NULL) {
+        return MQTT_ERROR_NULLPTR;
+    }
+
+    /* inspect QoS level */
+    inspected_qos = (publish_flags & MQTT_PUBLISH_QOS_MASK) >> 1; /* mask */
+
+    /* build the fixed header */
+    fixed_header.control_type = MQTT_CONTROL_PUBLISH;
+
+    /* calculate remaining length */
+    remaining_length = (uint16_t)__mqtt_packed_cstrlen(topic_name);
+    if (inspected_qos > 0) {
+        remaining_length += 2;
+    }
+    remaining_length += (uint16_t)application_message_size;
+    fixed_header.remaining_length = remaining_length;
+
+    /* force dup to 0 if qos is 0 [Spec MQTT-3.3.1-2] */
+    if (inspected_qos == 0) {
+        publish_flags &= ~MQTT_PUBLISH_DUP;
+    }
+
+    /* make sure that qos is not 3 [Spec MQTT-3.3.1-4] */
+    if (inspected_qos == 3) {
+        return MQTT_ERROR_PUBLISH_FORBIDDEN_QOS;
+    }
+    fixed_header.control_flags = publish_flags;
+
+    /* pack fixed header */
+    rv = mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+    if (rv <= 0) {
+        /* something went wrong */
+        return rv;
+    }
+    buf += rv;
+    bufsz -= rv;
+
+    /* check that buffer is big enough */
+    if (bufsz < remaining_length) {
+        return 0;
+    }
+
+    /* pack variable header */
+    buf += __mqtt_pack_str(buf, topic_name);
+    if (inspected_qos > 0) {
+        buf += __mqtt_pack_uint16(buf, packet_id);
+    }
+
+    /* pack payload */
+    memcpy(buf, application_message, application_message_size);
+    buf += application_message_size;
+
+    return buf - start;
+}
+
+ssize_t mqtt_unpack_publish_response(struct mqtt_response *mqtt_response, const uint8_t *buf)
+{    
+    const uint8_t *const start = buf;
+    struct mqtt_fixed_header *fixed_header;
+    struct mqtt_response_publish *response;
+    
+    fixed_header = &(mqtt_response->fixed_header);
+    response = &(mqtt_response->decoded.publish);
+
+    /* get flags */
+    response->dup_flag = (fixed_header->control_flags & MQTT_PUBLISH_DUP) >> 3;
+    response->qos_level = (fixed_header->control_flags & MQTT_PUBLISH_QOS_MASK) >> 1;
+    response->retain_flag = fixed_header->control_flags & MQTT_PUBLISH_RETAIN;
+
+    /* make sure that remaining length is valid */
+    if (mqtt_response->fixed_header.remaining_length < 4) {
+        return MQTT_ERROR_MALFORMED_RESPONSE;
+    }
+
+    /* parse variable header */
+    response->topic_name_size = __mqtt_unpack_uint16(buf);
+    buf += 2;
+    response->topic_name = buf;
+    buf += response->topic_name_size;
+
+    if (response->qos_level > 0) {
+        response->packet_id = __mqtt_unpack_uint16(buf);
+        buf += 2;
+    }
+
+    /* get payload */
+    response->application_message = buf;
+    if (response->qos_level == 0) {
+        response->application_message_size = fixed_header->remaining_length - response->topic_name_size - 2;
+    } else {
+        response->application_message_size = fixed_header->remaining_length - response->topic_name_size - 4;
+    }
+    buf += response->application_message_size;
+    
+    /* return number of bytes consumed */
+    return buf - start;
+}
+
+/* PUBXXX */
+ssize_t mqtt_pack_pubxxx_request(uint8_t *buf, size_t bufsz, 
+                                 enum MQTTControlPacketType control_type,
+                                 uint16_t packet_id) 
+{
+    const uint8_t *const start = buf;
+    struct mqtt_fixed_header fixed_header;
+    ssize_t rv;
+    if (buf == NULL) {
+        return MQTT_ERROR_NULLPTR;
+    }
+
+    /* pack fixed header */
+    fixed_header.control_type = control_type;
+    if (control_type == MQTT_CONTROL_PUBREL) {
+        fixed_header.control_flags = 0x02;
+    } else {
+        fixed_header.control_flags = 0;
+    }
+    fixed_header.remaining_length = 2;
+    rv = mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+    if (rv <= 0) {
+        return rv;
+    }
+    buf += rv;
+    bufsz -= rv;
+
+    if (bufsz < fixed_header.remaining_length) {
+        return 0;
+    }
+    
+    buf += __mqtt_pack_uint16(buf, packet_id);
+
+    return buf - start;
+}
+
+ssize_t mqtt_unpack_pubxxx_response(struct mqtt_response *mqtt_response, const uint8_t *buf) 
+{
+    const uint8_t *const start = buf;
+    uint16_t packet_id;
+
+    /* assert remaining length is correct */
+    if (mqtt_response->fixed_header.remaining_length != 2) {
+        return MQTT_ERROR_MALFORMED_RESPONSE;
+    }
+
+    /* parse packet_id */
+    packet_id = __mqtt_unpack_uint16(buf);
+    buf += 2;
+
+    if (mqtt_response->fixed_header.control_type == MQTT_CONTROL_PUBACK) {
+        mqtt_response->decoded.puback.packet_id = packet_id;
+    } else if (mqtt_response->fixed_header.control_type == MQTT_CONTROL_PUBREC) {
+        mqtt_response->decoded.pubrec.packet_id = packet_id;
+    } else if (mqtt_response->fixed_header.control_type == MQTT_CONTROL_PUBREL) {
+        mqtt_response->decoded.pubrel.packet_id = packet_id;
+    } else {
+        mqtt_response->decoded.pubcomp.packet_id = packet_id;
+    }
+
+    return buf - start;
+}
+
+/* SUBACK */
+ssize_t mqtt_unpack_suback_response (struct mqtt_response *mqtt_response, const uint8_t *buf) {
+    const uint8_t *const start = buf;
+    uint32_t remaining_length = mqtt_response->fixed_header.remaining_length;
+    
+    /* assert remaining length is at least 3 (for packet id and at least 1 topic) */
+    if (remaining_length < 3) {
+        return MQTT_ERROR_MALFORMED_RESPONSE;
+    }
+
+    /* unpack packet_id */
+    mqtt_response->decoded.suback.packet_id = __mqtt_unpack_uint16(buf);
+    buf += 2;
+    remaining_length -= 2;
+
+    /* unpack return codes */
+    mqtt_response->decoded.suback.num_return_codes = (size_t) remaining_length;
+    mqtt_response->decoded.suback.return_codes = buf;
+    buf += remaining_length;
+
+    return buf - start;
+}
+
+/* SUBSCRIBE */
+ssize_t mqtt_pack_subscribe_request(uint8_t *buf, size_t bufsz, unsigned int packet_id, ...) {
+    va_list args;
+    const uint8_t *const start = buf;
+    ssize_t rv;
+    struct mqtt_fixed_header fixed_header;
+    unsigned int num_subs = 0;
+    unsigned int i;
+    const char *topic[MQTT_SUBSCRIBE_REQUEST_MAX_NUM_TOPICS];
+    uint8_t max_qos[MQTT_SUBSCRIBE_REQUEST_MAX_NUM_TOPICS];
+
+    /* parse all subscriptions */
+    va_start(args, packet_id);
+    while(1) {
+        topic[num_subs] = va_arg(args, const char*);
+        if (topic[num_subs] == NULL) {
+            /* end of list */
+            break;
+        }
+
+        max_qos[num_subs] = (uint8_t) va_arg(args, unsigned int);
+
+        ++num_subs;
+        if (num_subs >= MQTT_SUBSCRIBE_REQUEST_MAX_NUM_TOPICS) {
+            return MQTT_ERROR_SUBSCRIBE_TOO_MANY_TOPICS;
+        }
+    }
+    va_end(args);
+
+    /* build the fixed header */
+    fixed_header.control_type = MQTT_CONTROL_SUBSCRIBE;
+    fixed_header.control_flags = 2u;
+    fixed_header.remaining_length = 2u; /* size of variable header */
+    for(i = 0; i < num_subs; ++i) {
+        /* payload is topic name + max qos (1 byte) */
+        fixed_header.remaining_length += __mqtt_packed_cstrlen(topic[i]) + 1;
+    }
+
+    /* pack the fixed header */
+    rv = mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+    if (rv <= 0) {
+        return rv;
+    }
+    buf += rv;
+    bufsz -= rv;
+
+    /* check that the buffer has enough space */
+    if (bufsz < fixed_header.remaining_length) {
+        return 0;
+    }
+    
+    
+    /* pack variable header */
+    buf += __mqtt_pack_uint16(buf, packet_id);
+
+
+    /* pack payload */
+    for(i = 0; i < num_subs; ++i) {
+        buf += __mqtt_pack_str(buf, topic[i]);
+        *buf++ = max_qos[i];
+    }
+
+    return buf - start;
+}
+
+/* UNSUBACK */
+ssize_t mqtt_unpack_unsuback_response(struct mqtt_response *mqtt_response, const uint8_t *buf) 
+{
+    const uint8_t *const start = buf;
+
+    if (mqtt_response->fixed_header.remaining_length != 2) {
+        return MQTT_ERROR_MALFORMED_RESPONSE;
+    }
+
+    /* parse packet_id */
+    mqtt_response->decoded.unsuback.packet_id = __mqtt_unpack_uint16(buf);
+    buf += 2;
+
+    return buf - start;
+}
+
+/* UNSUBSCRIBE */
+ssize_t mqtt_pack_unsubscribe_request(uint8_t *buf, size_t bufsz, unsigned int packet_id, ...) {
+    va_list args;
+    const uint8_t *const start = buf;
+    ssize_t rv;
+    struct mqtt_fixed_header fixed_header;
+    unsigned int num_subs = 0;
+    unsigned int i;
+    const char *topic[MQTT_UNSUBSCRIBE_REQUEST_MAX_NUM_TOPICS];
+
+    /* parse all subscriptions */
+    va_start(args, packet_id);
+    while(1) {
+        topic[num_subs] = va_arg(args, const char*);
+        if (topic[num_subs] == NULL) {
+            /* end of list */
+            break;
+        }
+
+        ++num_subs;
+        if (num_subs >= MQTT_UNSUBSCRIBE_REQUEST_MAX_NUM_TOPICS) {
+            return MQTT_ERROR_UNSUBSCRIBE_TOO_MANY_TOPICS;
+        }
+    }
+    va_end(args);
+
+    /* build the fixed header */
+    fixed_header.control_type = MQTT_CONTROL_UNSUBSCRIBE;
+    fixed_header.control_flags = 2u;
+    fixed_header.remaining_length = 2u; /* size of variable header */
+    for(i = 0; i < num_subs; ++i) {
+        /* payload is topic name */
+        fixed_header.remaining_length += __mqtt_packed_cstrlen(topic[i]);
+    }
+
+    /* pack the fixed header */
+    rv = mqtt_pack_fixed_header(buf, bufsz, &fixed_header);
+    if (rv <= 0) {
+        return rv;
+    }
+    buf += rv;
+    bufsz -= rv;
+
+    /* check that the buffer has enough space */
+    if (bufsz < fixed_header.remaining_length) {
+        return 0;
+    }
+
+    /* pack variable header */
+    buf += __mqtt_pack_uint16(buf, packet_id);
+
+
+    /* pack payload */
+    for(i = 0; i < num_subs; ++i) {
+        buf += __mqtt_pack_str(buf, topic[i]);
+    }
+
+    return buf - start;
+}
+
+/* MESSAGE QUEUE */
+void mqtt_mq_init(struct mqtt_message_queue *mq, void *buf, size_t bufsz) 
+{  
+    if(buf != NULL)
+    {
+        mq->mem_start = buf;
+        mq->mem_end = (unsigned char*)buf + bufsz;
+        mq->curr = buf;
+        mq->queue_tail = mq->mem_end;
+        mq->curr_sz = mqtt_mq_currsz(mq);
+    }
+}
+
+struct mqtt_queued_message* mqtt_mq_register(struct mqtt_message_queue *mq, size_t nbytes)
+{
+    /* make queued message header */
+    --(mq->queue_tail);
+    mq->queue_tail->start = mq->curr;
+    mq->queue_tail->size = nbytes;
+    mq->queue_tail->state = MQTT_QUEUED_UNSENT;
+
+    /* move curr and recalculate curr_sz */
+    mq->curr += nbytes;
+    mq->curr_sz = mqtt_mq_currsz(mq);
+
+    return mq->queue_tail;
+}
+
+void mqtt_mq_clean(struct mqtt_message_queue *mq) {
+    struct mqtt_queued_message *new_head;
+
+    for(new_head = mqtt_mq_get(mq, 0); new_head >= mq->queue_tail; --new_head) {
+        if (new_head->state != MQTT_QUEUED_COMPLETE) break;
+    }
+    
+    /* check if everything can be removed */
+    if (new_head < mq->queue_tail) {
+        mq->curr = mq->mem_start;
+        mq->queue_tail = mq->mem_end;
+        mq->curr_sz = mqtt_mq_currsz(mq);
+        return;
+    } else if (new_head == mqtt_mq_get(mq, 0)) {
+        /* do nothing */
+        return;
+    }
+
+    /* move buffered data */
+    {
+        size_t n = mq->curr - new_head->start;
+        size_t removing = new_head->start - (uint8_t*) mq->mem_start;
+        memmove(mq->mem_start, new_head->start, n);
+        mq->curr = (unsigned char*)mq->mem_start + n;
+      
+
+        /* move queue */
+        {
+            ssize_t new_tail_idx = new_head - mq->queue_tail;
+            memmove(mqtt_mq_get(mq, new_tail_idx), mq->queue_tail, sizeof(struct mqtt_queued_message) * (new_tail_idx + 1));
+            mq->queue_tail = mqtt_mq_get(mq, new_tail_idx);
+          
+            {
+                /* bump back start's */
+                ssize_t i = 0;
+                for(; i < new_tail_idx + 1; ++i) {
+                    mqtt_mq_get(mq, i)->start -= removing;
+                }
+            }
+        }
+    }
+
+    /* get curr_sz */
+    mq->curr_sz = mqtt_mq_currsz(mq);
+}
+
+struct mqtt_queued_message* mqtt_mq_find(struct mqtt_message_queue *mq, enum MQTTControlPacketType control_type, uint16_t *packet_id)
+{
+    struct mqtt_queued_message *curr;
+    for(curr = mqtt_mq_get(mq, 0); curr >= mq->queue_tail; --curr) {
+        if (curr->control_type == control_type) {
+            if ((packet_id == NULL && curr->state != MQTT_QUEUED_COMPLETE) ||
+                (packet_id != NULL && *packet_id == curr->packet_id)) {
+                return curr;
+            }
+        }
+    }
+    return NULL;
+}
+
+
+/* RESPONSE UNPACKING */
+ssize_t mqtt_unpack_response(struct mqtt_response* response, const uint8_t *buf, size_t bufsz) {
+    const uint8_t *const start = buf;
+    ssize_t rv = mqtt_unpack_fixed_header(response, buf, bufsz);
+    if (rv <= 0) return rv;
+    else buf += rv;
+    switch(response->fixed_header.control_type) {
+        case MQTT_CONTROL_CONNACK:
+            rv = mqtt_unpack_connack_response(response, buf);
+            break;
+        case MQTT_CONTROL_PUBLISH:
+            rv = mqtt_unpack_publish_response(response, buf);
+            break;
+        case MQTT_CONTROL_PUBACK:
+            rv = mqtt_unpack_pubxxx_response(response, buf);
+            break;
+        case MQTT_CONTROL_PUBREC:
+            rv = mqtt_unpack_pubxxx_response(response, buf);
+            break;
+        case MQTT_CONTROL_PUBREL:
+            rv = mqtt_unpack_pubxxx_response(response, buf);
+            break;
+        case MQTT_CONTROL_PUBCOMP:
+            rv = mqtt_unpack_pubxxx_response(response, buf);
+            break;
+        case MQTT_CONTROL_SUBACK:
+            rv = mqtt_unpack_suback_response(response, buf);
+            break;
+        case MQTT_CONTROL_UNSUBACK:
+            rv = mqtt_unpack_unsuback_response(response, buf);
+            break;
+        case MQTT_CONTROL_PINGRESP:
+            return rv;
+        default:
+            return MQTT_ERROR_RESPONSE_INVALID_CONTROL_TYPE;
+    }
+
+    if (rv < 0) return rv;
+    buf += rv;
+    return buf - start;
+}
+
+/* EXTRA DETAILS */
+ssize_t __mqtt_pack_uint16(uint8_t *buf, uint16_t integer)
+{
+  uint16_t integer_htons = MQTT_PAL_HTONS(integer);
+  memcpy(buf, &integer_htons, 2);
+  return 2;
+}
+
+uint16_t __mqtt_unpack_uint16(const uint8_t *buf)
+{
+  uint16_t integer_htons;
+  memcpy(&integer_htons, buf, 2);
+  return MQTT_PAL_NTOHS(integer_htons);
+}
+
+ssize_t __mqtt_pack_str(uint8_t *buf, const char* str) {
+    uint16_t length = (uint16_t)strlen(str);
+    int i = 0;
+     /* pack string length */
+    buf += __mqtt_pack_uint16(buf, length);
+
+    /* pack string */
+    for(; i < length; ++i) {
+        *(buf++) = str[i];
+    }
+    
+    /* return number of bytes consumed */
+    return length + 2;
+}
+
+static const char *MQTT_ERRORS_STR[] = {
+    "MQTT_UNKNOWN_ERROR",
+    __ALL_MQTT_ERRORS(GENERATE_STRING)
+};
+
+const char* mqtt_error_str(enum MQTTErrors error) {
+    int offset = error - MQTT_ERROR_UNKNOWN;
+    if (offset >= 0) {
+        return MQTT_ERRORS_STR[offset];
+    } else if (error == 0) {
+        return "MQTT_ERROR: Buffer too small.";
+    } else if (error > 0) {
+        return "MQTT_OK";
+    } else {
+        return MQTT_ERRORS_STR[0];
+    }
+}
+
+/** @endcond*/

deps/MQTT-C/src/mqtt_pal.c

+/*
+MIT License
+
+Copyright(c) 2018 Liam Bindle
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#include <mqtt.h>
+
+/** 
+ * @file 
+ * @brief Implements @ref mqtt_pal_sendall and @ref mqtt_pal_recvall and 
+ *        any platform-specific helpers you'd like.
+ * @cond Doxygen_Suppress
+ */
+
+
+#ifdef MQTT_USE_MBEDTLS
+#include <mbedtls/ssl.h>
+
+ssize_t mqtt_pal_sendall(mqtt_pal_socket_handle fd, const void* buf, size_t len, int flags) {
+    size_t sent = 0;
+    while(sent < len) {
+        int rv = mbedtls_ssl_write(fd, buf + sent, len - sent);
+        if (rv < 0) {
+            if (rv == MBEDTLS_ERR_SSL_WANT_READ ||
+                rv == MBEDTLS_ERR_SSL_WANT_WRITE
+#if defined(MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS)
+                || rv == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS
+#endif
+#if defined(MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS)
+                || rv == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS
+#endif
+                ) {
+                /* should call mbedtls_ssl_writer later again */
+                break;
+            }
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+        sent += (size_t) rv;
+    }
+    return sent;
+}
+
+ssize_t mqtt_pal_recvall(mqtt_pal_socket_handle fd, void* buf, size_t bufsz, int flags) {
+    const void *const start = buf;
+    int rv;
+    do {
+        rv = mbedtls_ssl_read(fd, buf, bufsz);
+        if (rv < 0) {
+            if (rv == MBEDTLS_ERR_SSL_WANT_READ ||
+                rv == MBEDTLS_ERR_SSL_WANT_WRITE
+#if defined(MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS)
+                || rv == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS
+#endif
+#if defined(MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS)
+                || rv == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS
+#endif
+                ) {
+                /* should call mbedtls_ssl_read later again */
+                break;
+            }
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+        buf = (char*)buf + rv;
+        bufsz -= rv;
+    } while (rv > 0);
+
+    return buf - start;
+}
+
+#elif defined(MQTT_USE_BIO)
+#include <openssl/bio.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+
+ssize_t mqtt_pal_sendall(mqtt_pal_socket_handle fd, const void* buf, size_t len, int flags) {
+    size_t sent = 0;
+    while(sent < len) {
+        int tmp = BIO_write(fd, buf + sent, len - sent);
+        if (tmp > 0) {
+            sent += (size_t) tmp;
+        } else if (tmp <= 0 && !BIO_should_retry(fd)) {
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+    }
+    
+    return sent;
+}
+
+ssize_t mqtt_pal_recvall(mqtt_pal_socket_handle fd, void* buf, size_t bufsz, int flags) {
+    const void *const start = buf;
+    int rv;
+    do {
+        rv = BIO_read(fd, buf, bufsz);
+        if (rv > 0) {
+            /* successfully read bytes from the socket */
+            buf += rv;
+            bufsz -= rv;
+        } else if (!BIO_should_retry(fd)) {
+            /* an error occurred that wasn't "nothing to read". */
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+    } while (!BIO_should_read(fd));
+
+    return (ssize_t)(buf - start);
+}
+
+#elif defined(__unix__) || defined(__APPLE__)
+
+#include <errno.h>
+
+ssize_t mqtt_pal_sendall(mqtt_pal_socket_handle fd, const void* buf, size_t len, int flags) {
+    size_t sent = 0;
+    while(sent < len) {
+        ssize_t tmp = send(fd, buf + sent, len - sent, flags);
+        if (tmp < 1) {
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+        sent += (size_t) tmp;
+    }
+    return sent;
+}
+
+ssize_t mqtt_pal_recvall(mqtt_pal_socket_handle fd, void* buf, size_t bufsz, int flags) {
+    const void *const start = buf;
+    ssize_t rv;
+    do {
+        rv = recv(fd, buf, bufsz, flags);
+        if (rv > 0) {
+            /* successfully read bytes from the socket */
+            buf += rv;
+            bufsz -= rv;
+        } else if (rv < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
+            /* an error occurred that wasn't "nothing to read". */
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+    } while (rv > 0);
+
+    return buf - start;
+}
+
+#elif defined(_MSC_VER)
+
+#include <errno.h>
+
+ssize_t mqtt_pal_sendall(mqtt_pal_socket_handle fd, const void* buf, size_t len, int flags) {
+    size_t sent = 0;
+    while(sent < len) {
+        ssize_t tmp = send(fd, (char*)buf + sent, len - sent, flags);
+        if (tmp < 1) {
+            return MQTT_ERROR_SOCKET_ERROR;
+        }
+        sent += (size_t) tmp;
+    }
+    return sent;
+}
+
+ssize_t mqtt_pal_recvall(mqtt_pal_socket_handle fd, void* buf, size_t bufsz, int flags) {
+    const char *const start = buf;
+    ssize_t rv;
+    do {
+        rv = recv(fd, buf, bufsz, flags);
+        if (rv > 0) {
+            /* successfully read bytes from the socket */
+            buf = (char*)buf + rv;
+            bufsz -= rv;
+        } else if (rv < 0) {
+            int err = WSAGetLastError();
+            if (err != WSAEWOULDBLOCK) {
+                /* an error occurred that wasn't "nothing to read". */
+                return MQTT_ERROR_SOCKET_ERROR;
+            }
+        }
+    } while (rv > 0);
+
+    return (ssize_t)((char*)buf - start);
+}
+
+#else
+
+#error No PAL!
+
+#endif
+
+/** @endcond */

deps/MQTT-C/tests.c

+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <time.h>
+
+#if !defined(WIN32)
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <sys/wait.h>
+#else
+#include <ws2tcpip.h>
+
+/* Some shortcuts to call winapi in a posix-like way */
+#define close(sock)         closesocket(sock)
+#define usleep(usec)        Sleep((usec) / 1000)
+#endif
+
+
+#include <mqtt.h>
+#include "examples/templates/posix_sockets.h"
+
+void make_socket_blocking(int socket)
+{
+#if !defined(WIN32)
+    fcntl(socket, F_SETFL, fcntl(socket, F_GETFL) & ~O_NONBLOCK);
+#else
+    int iMode = 0;
+    ioctlsocket(socket, FIONBIO, &iMode);
+#endif
+}
+
+
+
+const char* addr = "test.mosquitto.org";
+const char* port = "1883";
+
+static void TEST__framing__fixed_header(void** state) {
+    static uint32_t remaining_lengths[] = { 0, 127, 128, 16383, 16384, 2097151, 2097152, 268435455, 268435456 };
+    static ssize_t  actual_lengths[] = { 2, 2, 3, 3, 4, 4, 5, 5, MQTT_ERROR_INVALID_REMAINING_LENGTH };
+    uint8_t correct_buf[1024];
+    uint8_t buf[1024];
+    struct mqtt_response response;
+    struct mqtt_fixed_header *fixed_header = &response.fixed_header;
+    ssize_t rv;
+    size_t k;
+
+    /*
+     * remaining length tests on pack and unpack
+     */
+    for(k = 0; k < sizeof(remaining_lengths)/sizeof(remaining_lengths[0]); ++k) {
+        fixed_header->control_type = MQTT_CONTROL_CONNECT;
+        fixed_header->control_flags = 0;
+        fixed_header->remaining_length = remaining_lengths[k];
+
+        /* the length is a necessary lie */
+        rv = mqtt_pack_fixed_header(buf, sizeof(buf) + remaining_lengths[k], fixed_header);
+        assert_true(rv == actual_lengths[k]);
+
+        if(k == 8)
+            buf[4] = 0x86;
+
+        /* another unavoidable lie */
+    rv = mqtt_unpack_fixed_header(&response, buf, sizeof(buf) + remaining_lengths[k]);
+    assert_true(rv == actual_lengths[k]);
+
+        if(k != 8)
+            assert_true(remaining_lengths[k] == response.fixed_header.remaining_length);
+    }
+
+    /* sanity check with valid fixed_header */
+    correct_buf[0] = (MQTT_CONTROL_CONNECT << 4) | 0;
+    correct_buf[1] = 193u;
+    correct_buf[2] = 2u;
+
+    /* check that unpack is correct */
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 3);
+    assert_true(fixed_header->control_type == MQTT_CONTROL_CONNECT);
+    assert_true(fixed_header->control_flags == 0);
+    assert_true(fixed_header->remaining_length == 321);
+
+    /* check that unpack is correct */
+    rv = mqtt_pack_fixed_header(buf, sizeof(buf), fixed_header);
+    assert_true(rv == 3);
+    assert_true(memcmp(correct_buf, buf, 3) == 0);
+
+
+    /* check that invalid flags are caught */
+    correct_buf[0] = (MQTT_CONTROL_CONNECT << 4) | 1;
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == MQTT_ERROR_CONTROL_INVALID_FLAGS);
+
+    /* check that valid flags are ok when there is a required bit */
+    correct_buf[0] = (MQTT_CONTROL_PUBREL << 4) | 2;
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 3);
+
+    /* check that invalid flags are ok when there is a required bit */
+    correct_buf[0] = (MQTT_CONTROL_PUBREL << 4) | 3;
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == MQTT_ERROR_CONTROL_INVALID_FLAGS);
+
+    /* check that valid flags are ok when there are optional flags */
+    correct_buf[0] = (MQTT_CONTROL_PUBLISH << 4) | 0xF;
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 3);
+    
+    correct_buf[0] = (MQTT_CONTROL_PUBLISH << 4) | 3;
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 3);
+
+
+    /* check that remaining length is packed/unpacked correctly */
+    correct_buf[0] = (MQTT_CONTROL_CONNECT << 4) | 0;
+    correct_buf[1] = 64;
+
+    /* check that unpack is correct */
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 2);
+    assert_true(fixed_header->control_type == MQTT_CONTROL_CONNECT);
+    assert_true(fixed_header->control_flags == 0);
+    assert_true(fixed_header->remaining_length == 64);
+
+    /* check that unpack is correct */
+    rv = mqtt_pack_fixed_header(buf, sizeof(buf), fixed_header);
+    assert_true(rv == 2);
+    assert_true(memcmp(correct_buf, buf, 2) == 0);
+
+
+    /* check that remaining length is packed/unpacked correctly */
+    correct_buf[0] = (MQTT_CONTROL_CONNECT << 4) | 0;
+    correct_buf[1] = 127;
+
+    /* check that unpack is correct */
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 2);
+    assert_true(fixed_header->control_type == MQTT_CONTROL_CONNECT);
+    assert_true(fixed_header->control_flags == 0);
+    assert_true(fixed_header->remaining_length == 127);
+
+    /* check that unpack is correct */
+    rv = mqtt_pack_fixed_header(buf, sizeof(buf), fixed_header);
+    assert_true(rv == 2);
+    assert_true(memcmp(correct_buf, buf, 2) == 0);
+
+
+    /* check that remaining length is packed/unpacked correctly */
+    correct_buf[0] = (MQTT_CONTROL_CONNECT << 4) | 0;
+    correct_buf[1] = 128;
+    correct_buf[2] = 1;
+
+    /* check that unpack is correct */
+    rv = mqtt_unpack_fixed_header(&response, correct_buf, sizeof(correct_buf));
+    assert_true(rv == 3);
+    assert_true(fixed_header->control_type == MQTT_CONTROL_CONNECT);
+    assert_true(fixed_header->control_flags == 0);
+    assert_true(fixed_header->remaining_length == 128);
+
+    /* check that unpack is correct */
+    rv = mqtt_pack_fixed_header(buf, sizeof(buf), fixed_header);
+    assert_true(rv == 3);
+    assert_true(memcmp(correct_buf, buf, 3) == 0);
+
+    /* check bad inputs */
+    assert_true( mqtt_pack_fixed_header(NULL, 5, fixed_header) == MQTT_ERROR_NULLPTR );
+    assert_true( mqtt_pack_fixed_header(buf, 5, NULL) == MQTT_ERROR_NULLPTR );
+    assert_true( mqtt_pack_fixed_header(buf, 2, fixed_header) == 0 );
+
+    assert_true( mqtt_unpack_fixed_header(NULL, buf, 5) == MQTT_ERROR_NULLPTR );
+    assert_true( mqtt_unpack_fixed_header(&response, NULL, 5) == MQTT_ERROR_NULLPTR );
+    assert_true( mqtt_unpack_fixed_header(&response, buf, 2) == 0 );
+}
+
+static void TEST__framing__connect(void** state) {
+    uint8_t buf[256];
+    ssize_t rv;
+    const uint8_t correct_bytes[] = {
+        (MQTT_CONTROL_CONNECT << 4) | 0, 16,
+        0, 4, 'M', 'Q', 'T', 'T', MQTT_PROTOCOL_LEVEL, 0, 0, 120u, 
+        0, 4, 'l', 'i', 'a', 'm'
+    };
+    const uint8_t correct_bytes2[] = {
+        (MQTT_CONTROL_CONNECT << 4) | 0, 51,
+        0, 4, 'M', 'Q', 'T', 'T', MQTT_PROTOCOL_LEVEL, 
+        MQTT_CONNECT_WILL_FLAG | MQTT_CONNECT_USER_NAME | MQTT_CONNECT_PASSWORD, 
+        0, 120u, 
+        0, 4, 'l', 'i', 'a', 'm',
+        0, 9, 'w', 'i', 'l', 'l', 't', 'o', 'p', 'i', 'c',
+        0, 2, 'h', 'i',
+        0, 8, 'u', 's', 'e', 'r', 'n', 'a', 'm', 'e',
+        0, 8, 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'
+    };
+    const uint8_t correct_bytes_empty_client_id[] = {
+        (MQTT_CONTROL_CONNECT << 4) | 0, 12,
+        0, 4, 'M', 'Q', 'T', 'T', MQTT_PROTOCOL_LEVEL, MQTT_CONNECT_CLEAN_SESSION,
+        0, 120u, 0, 0
+    };
+
+    struct mqtt_response response;
+    struct mqtt_fixed_header *fixed_header = &response.fixed_header;
+
+    rv = mqtt_pack_connection_request(buf, sizeof(buf), "liam", NULL, NULL, 0, NULL, NULL, 0, 120u);
+    assert_true(rv == sizeof(correct_bytes));
+
+    /* check that fixed header is correct */
+    rv = mqtt_unpack_fixed_header(&response, buf, rv);
+    assert_true(fixed_header->control_type == MQTT_CONTROL_CONNECT);
+    assert_true(fixed_header->remaining_length == 16);
+
+    /* check that memory is correct */
+    assert_true(memcmp(correct_bytes, buf, sizeof(correct_bytes)) == 0);
+
+    /* check that will flags are okay and user name and password */
+    rv = mqtt_pack_connection_request(buf, sizeof(buf), "liam", "willtopic", "hi", 2, "username", "password", 0, 120u);
+    assert_true(rv == sizeof(correct_bytes2));
+
+    /* check that memory is correct */
+    assert_true(memcmp(correct_bytes2, buf, sizeof(correct_bytes2)) == 0);
+
+    /* check that the empty client_id is packed correctly */
+    rv = mqtt_pack_connection_request(buf, sizeof(buf), NULL, NULL, NULL, 0, NULL, NULL, MQTT_CONNECT_CLEAN_SESSION, 120u);
+    assert_true(rv == sizeof(correct_bytes_empty_client_id));
+
+    /* check that memory is correct */
+    assert_true(memcmp(correct_bytes_empty_client_id, buf, sizeof(correct_bytes_empty_client_id)) == 0);
+
+    /* Check that empty client_id is rejected without MQTT_CONNECT_CLEAN_SESSION */
+    rv = mqtt_pack_connection_request(buf, sizeof(buf), NULL, NULL, NULL, 0, NULL, NULL, 0, 120u);
+    assert_int_equal(rv, MQTT_ERROR_CLEAN_SESSION_IS_REQUIRED);
+}
+
+static void TEST__framing__publish(void** state) {
+    uint8_t buf[256];
+    ssize_t rv;
+    const uint8_t correct_bytes[] = {
+        (MQTT_CONTROL_PUBLISH << 4) | MQTT_PUBLISH_RETAIN, 18,
+        0, 6, 't', 'o', 'p', 'i', 'c', '1',
+        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
+    };
+    struct mqtt_response mqtt_response;
+    struct mqtt_response_publish *response;
+    response = &(mqtt_response.decoded.publish);
+    
+    
+    rv = mqtt_pack_publish_request(buf, 256, "topic1", 23, "0123456789", 10, MQTT_PUBLISH_RETAIN);
+    assert_true(rv == 20);
+    assert_true(memcmp(buf, correct_bytes, 20) == 0);
+
+    rv = mqtt_unpack_fixed_header(&mqtt_response, buf, 20);
+    assert_true(rv == 2);
+    rv = mqtt_unpack_publish_response(&mqtt_response, buf + 2);
+    assert_true(response->qos_level == 0);
+    assert_true(response->retain_flag == 1);
+    assert_true(response->dup_flag == 0);
+    assert_true(response->topic_name_size == 6);
+    assert_true(memcmp(response->topic_name, "topic1", 6) == 0);
+    assert_true(response->application_message_size == 10);
+    assert_true(memcmp(response->application_message, "0123456789", 10) == 0);
+}
+
+static void TEST__utility__connect_disconnect(void** state) {
+    uint8_t buf[256];
+    struct mqtt_client client;
+    ssize_t rv;
+    struct mqtt_response mqtt_response;
+
+    client.socketfd = open_nb_socket(addr, port);
+    make_socket_blocking(client.socketfd);
+    assert_true(client.socketfd != -1);
+
+    rv = mqtt_pack_connection_request(buf, sizeof(buf), "liam-123456", NULL, NULL, 0, NULL, NULL, 0, 30);
+    assert_true(rv > 0);
+    assert_true(send(client.socketfd, buf, rv, 0) != -1);
+
+    /* receive connack */
+    assert_true(recv(client.socketfd, buf, sizeof(buf), 0) != -1);
+    rv = mqtt_unpack_fixed_header(&mqtt_response, buf, sizeof(buf));
+    assert_true(rv > 0);
+    assert_true(mqtt_unpack_connack_response(&mqtt_response, buf + rv) > 0);
+    assert_true(mqtt_response.decoded.connack.return_code == MQTT_CONNACK_ACCEPTED);
+
+    /* disconnect */
+    rv = mqtt_pack_disconnect(buf, sizeof(buf));
+    assert_true(rv > 0);
+    assert_true(send(client.socketfd, buf, rv, 0) != -1);
+
+    /*close the socket */
+    close(client.socketfd);
+}
+
+static void TEST__framing__connack(void** state) {
+    uint8_t buf[] = {
+        (MQTT_CONTROL_CONNACK << 4) | 0, 2,        
+        0, MQTT_CONNACK_ACCEPTED
+    };
+    struct mqtt_response mqtt_response;
+    ssize_t rv = mqtt_unpack_fixed_header(&mqtt_response, buf, sizeof(buf));
+    assert_true(rv == 2);
+    assert_true(mqtt_response.fixed_header.control_type == MQTT_CONTROL_CONNACK);
+
+    /* unpack response */
+    rv = mqtt_unpack_connack_response(&mqtt_response, buf+2);
+    assert_true(rv == 2);
+    assert_true(mqtt_response.decoded.connack.session_present_flag == 0);
+    assert_true(mqtt_response.decoded.connack.return_code == MQTT_CONNACK_ACCEPTED);
+}
+
+static void TEST__framing__pubxxx(void** state) {
+    uint8_t buf[256];
+    ssize_t rv;
+    struct mqtt_response response;
+    uint8_t puback_correct_bytes[] = {
+        MQTT_CONTROL_PUBACK << 4, 2,
+        0, 213u
+    };
+    uint8_t pubrec_correct_bytes[] = {
+        MQTT_CONTROL_PUBREC << 4, 2,
+        0, 213u
+    };
+    uint8_t pubrel_correct_bytes[] = {
+        MQTT_CONTROL_PUBREL << 4 | 2u, 2,
+        0, 213u
+    };
+    uint8_t pubcomp_correct_bytes[] = {
+        MQTT_CONTROL_PUBCOMP << 4, 2,
+        0, 213u
+    };
+
+    /* puback */
+    rv = mqtt_pack_pubxxx_request(buf, 256, MQTT_CONTROL_PUBACK, 213u);
+    assert_true(rv == 4);
+    assert_true(memcmp(puback_correct_bytes, buf, 4) == 0);
+
+    rv = mqtt_unpack_fixed_header(&response, buf, 256);
+    assert_true(rv == 2);
+    assert_true(response.fixed_header.control_type == MQTT_CONTROL_PUBACK);
+    rv = mqtt_unpack_pubxxx_response(&response, buf + 2);
+    assert_true(rv == 2);
+    assert_true(response.decoded.puback.packet_id == 213u);
+
+    /* pubrec */
+    rv = mqtt_pack_pubxxx_request(buf, 256, MQTT_CONTROL_PUBREC, 213u);
+    assert_true(rv == 4);
+    assert_true(memcmp(pubrec_correct_bytes, buf, 4) == 0);
+
+    rv = mqtt_unpack_fixed_header(&response, buf, 256);
+    assert_true(rv == 2);
+    assert_true(response.fixed_header.control_type == MQTT_CONTROL_PUBREC);
+    rv = mqtt_unpack_pubxxx_response(&response, buf + 2);
+    assert_true(rv == 2);
+    assert_true(response.decoded.pubrec.packet_id == 213u);
+
+    /* pubrel */
+    rv = mqtt_pack_pubxxx_request(buf, 256, MQTT_CONTROL_PUBREL, 213u);
+    assert_true(rv == 4);
+    assert_true(memcmp(pubrel_correct_bytes, buf, 4) == 0);
+
+    rv = mqtt_unpack_fixed_header(&response, buf, 256);
+    assert_true(rv == 2);
+    assert_true(response.fixed_header.control_type == MQTT_CONTROL_PUBREL);
+    rv = mqtt_unpack_pubxxx_response(&response, buf + 2);
+    assert_true(rv == 2);
+    assert_true(response.decoded.pubrel.packet_id == 213u);
+
+    /* pubcomp */
+    rv = mqtt_pack_pubxxx_request(buf, 256, MQTT_CONTROL_PUBCOMP, 213u);
+    assert_true(rv == 4);
+    assert_true(memcmp(pubcomp_correct_bytes, buf, 4) == 0);
+
+    rv = mqtt_unpack_fixed_header(&response, buf, 256);
+    assert_true(rv == 2);
+    assert_true(response.fixed_header.control_type == MQTT_CONTROL_PUBCOMP);
+    rv = mqtt_unpack_pubxxx_response(&response, buf + 2);
+    assert_true(rv == 2);
+    assert_true(response.decoded.pubcomp.packet_id == 213u);
+}
+
+static void TEST__framing__subscribe(void** state) {
+    uint8_t buf[256];
+    ssize_t rv;
+    const uint8_t correct[] = {
+        MQTT_CONTROL_SUBSCRIBE << 4 | 2u, 23,
+        0, 132u,
+        0, 3, 'a', '/', 'b', 0u,
+        0, 5, 'b', 'b', 'b', '/', 'x', 1u,
+        0, 4, 'c', '/', 'd', 'd', 0u,
+    };
+
+    rv = mqtt_pack_subscribe_request(buf, 256, 132, "a/b", 0, "bbb/x", 1, "c/dd", 0, NULL);
+    assert_true(rv == 25);
+    assert_true(memcmp(buf, correct, 25) == 0);
+}
+
+static void TEST__framing__suback(void** state) {
+    ssize_t rv;
+    struct mqtt_response response;
+    const uint8_t buf[] = {
+        MQTT_CONTROL_SUBACK << 4, 5,
+        0, 132u,
+        MQTT_SUBACK_SUCCESS_MAX_QOS_0,
+        MQTT_SUBACK_SUCCESS_MAX_QOS_1,
+        MQTT_SUBACK_FAILURE
+    };
+    rv = mqtt_unpack_fixed_header(&response, buf, sizeof(buf));
+    assert_true(rv == 2);
+    assert_true(response.fixed_header.control_type == MQTT_CONTROL_SUBACK);
+    rv = mqtt_unpack_suback_response(&response, buf + 2);
+    assert_true(rv == 5);
+    assert_true(response.decoded.suback.packet_id == 132u);
+    assert_true(response.decoded.suback.num_return_codes == 3);
+    assert_true(response.decoded.suback.return_codes[0] == MQTT_SUBACK_SUCCESS_MAX_QOS_0);
+    assert_true(response.decoded.suback.return_codes[1] == MQTT_SUBACK_SUCCESS_MAX_QOS_1);
+    assert_true(response.decoded.suback.return_codes[2] == MQTT_SUBACK_FAILURE);
+}
+
+static void TEST__framing__unsubscribe(void** state) {
+    uint8_t buf[256];
+    ssize_t rv;
+    const uint8_t correct[] = {
+        MQTT_CONTROL_UNSUBSCRIBE << 4 | 2u, 20,
+        0, 132u,
+        0, 3, 'a', '/', 'b',
+        0, 5, 'b', 'b', 'b', '/', 'x',
+        0, 4, 'c', '/', 'd', 'd',
+    };
+
+    rv = mqtt_pack_unsubscribe_request(buf, 256, 132, "a/b", "bbb/x", "c/dd", NULL);
+    assert_true(rv == 22);
+    assert_true(memcmp(buf, correct, sizeof(correct)) == 0);
+}
+
+static void TEST__framing__unsuback(void** state) {
+    uint8_t buf[] = {
+        MQTT_CONTROL_UNSUBACK << 4, 2,
+        0, 213u
+    };
+    ssize_t rv;
+    struct mqtt_response response;
+
+    rv = mqtt_unpack_fixed_header(&response, buf, 4);
+    assert_true(rv == 2);
+    assert_true(response.fixed_header.control_type == MQTT_CONTROL_UNSUBACK);
+    rv = mqtt_unpack_unsuback_response(&response, buf + 2);
+    assert_true(rv == 2);
+    assert_true(response.decoded.unsuback.packet_id == 213u);
+}
+
+static void TEST__framing__disconnect(void** state) {
+    uint8_t buf[2];
+    assert_true(mqtt_pack_disconnect(buf, 2) == 2);   
+}
+
+static void TEST__framing__ping(void** state) {
+    uint8_t buf[2];
+    struct mqtt_response response;
+    struct mqtt_fixed_header *fixed_header = &response.fixed_header;
+    assert_true(mqtt_pack_ping_request(buf, 2) == 2);   
+    assert_true(mqtt_unpack_fixed_header(&response, buf, 2) == 2);
+    assert_true(fixed_header->control_type == MQTT_CONTROL_PINGREQ);
+    assert_true(fixed_header->remaining_length == 0);
+}
+
+static void TEST__utility__ping(void** state) {
+    uint8_t buf[256];
+    struct mqtt_client client;
+    ssize_t rv;
+    struct mqtt_response mqtt_response;
+
+    client.socketfd = open_nb_socket(addr, port);
+    make_socket_blocking(client.socketfd);
+    assert_true(client.socketfd != -1);
+
+    rv = mqtt_pack_connection_request(buf, sizeof(buf), "this-is-me", NULL, NULL, 0, NULL, NULL, 0, 30);
+    assert_true(rv > 0);
+    assert_true(send(client.socketfd, buf, rv, 0) != -1);
+
+    /* receive connack */
+    assert_true(recv(client.socketfd, buf, sizeof(buf), 0) != -1);
+    rv = mqtt_unpack_fixed_header(&mqtt_response, buf, sizeof(buf));
+    assert_true(rv > 0);
+    assert_true(mqtt_unpack_connack_response(&mqtt_response, buf + rv) > 0);
+    assert_true(mqtt_response.decoded.connack.return_code == MQTT_CONNACK_ACCEPTED);
+
+    /* send ping request */
+    rv = mqtt_pack_ping_request(buf, sizeof(buf));
+    assert_true(rv > 0);
+    assert_true(send(client.socketfd, buf, rv, 0) != -1);
+
+    /* receive ping response */
+    assert_true(recv(client.socketfd, buf, sizeof(buf), 0) != -1);
+    rv = mqtt_unpack_fixed_header(&mqtt_response, buf, sizeof(buf));
+    assert_true(rv > 0);
+    assert_true(mqtt_response.fixed_header.control_type == MQTT_CONTROL_PINGRESP);
+
+    /* disconnect */
+    rv = mqtt_pack_disconnect(buf, sizeof(buf));
+    assert_true(rv > 0);
+    assert_true(send(client.socketfd, buf, rv, 0) != -1);
+
+    /*close the socket */
+    close(client.socketfd);
+}
+
+#define QM_SZ (int) sizeof(struct mqtt_queued_message)
+static void TEST__utility__message_queue(void **unused) {
+    uint8_t mem[32 + 4*QM_SZ];
+    struct mqtt_message_queue mq;
+    struct mqtt_queued_message *tail;
+    mqtt_mq_init(&mq, mem, sizeof(mem));
+
+    /* check that it fills up correctly */
+    assert_true(mqtt_mq_length(&mq) == 0);
+    assert_true(mq.curr_sz == 32 + 3*QM_SZ);
+    memset(mq.curr, 0, 8);
+    tail = mqtt_mq_register(&mq, 8);
+    tail->control_type = 2;
+    tail->packet_id = 111;
+    assert_true(mqtt_mq_length(&mq) == 1);
+    assert_true(mq.curr_sz == 24 + 2*QM_SZ);
+    memset(mq.curr, 1, 8);
+    tail = mqtt_mq_register(&mq, 8);
+    tail->control_type = 3;
+    tail->packet_id = 222;
+    assert_true(mqtt_mq_length(&mq) == 2);
+    assert_true(mq.curr_sz == 16 + 1*QM_SZ);
+    memset(mq.curr, 2, 8);
+    tail = mqtt_mq_register(&mq, 8);
+    tail->control_type = 4;
+    tail->packet_id = 333;
+    assert_true(mqtt_mq_length(&mq) == 3);
+    assert_true(mq.curr_sz == 8);
+    memset(mq.curr, 3, 8);
+    tail = mqtt_mq_register(&mq, 8);
+    tail->control_type = 5;
+    tail->packet_id = 444;
+    assert_true(mqtt_mq_length(&mq) == 4);
+    assert_true(mq.curr_sz == 0);
+    assert_true(mq.curr == (uint8_t*) mq.queue_tail);
+
+    /* check that start's are correct */
+    for(unsigned int i = 0; i < 4; ++i) {
+        assert_true(mqtt_mq_get(&mq, i)->start == (uint8_t*) mq.mem_start + 8*i);
+        for(int j = 0; j < 8; ++j) {
+            assert_true(mqtt_mq_get(&mq, i)->start[j] == i);
+        }
+
+        assert_true(mqtt_mq_get(&mq, i)->control_type == i + 2);
+        assert_true(mqtt_mq_get(&mq, i)->packet_id == 111 * (i + 1));
+    }
+
+    /* check that it cleans correctly */
+    mqtt_mq_clean(&mq);   /* should do nothing */
+    assert_true(mqtt_mq_length(&mq) == 4);
+    assert_true(mq.curr_sz == 0);
+    assert_true(mq.curr == (uint8_t*) mq.queue_tail);
+
+    /* try clearing middle (should do nothing) */
+    mqtt_mq_get(&mq, 1)->state = MQTT_QUEUED_COMPLETE;
+    mqtt_mq_get(&mq, 0)->state = MQTT_QUEUED_AWAITING_ACK;
+    mqtt_mq_clean(&mq);
+    assert_true(mqtt_mq_length(&mq) == 4);
+    assert_true(mq.curr_sz == 0);
+    assert_true(mq.curr == (uint8_t*) mq.queue_tail);
+
+    /* complete first then clean (should clear 2) */
+    mqtt_mq_get(&mq, 0)->state = MQTT_QUEUED_COMPLETE;
+    mqtt_mq_clean(&mq);
+    assert_true(mqtt_mq_length(&mq) == 2);
+    assert_true(mq.curr_sz == 16 + 1*QM_SZ);
+    assert_true(mq.curr == mem + 16);
+
+    /* check that start's are correct */
+    for(unsigned int i = 0; i < 2; ++i) {
+        assert_true(mqtt_mq_get(&mq, i)->start == (uint8_t*) mq.mem_start + 8*i);
+        for(int j = 0; j < 8; ++j) {
+            assert_true(mqtt_mq_get(&mq, i)->start[j] == i+2); /* check value */
+        }
+        assert_true(mqtt_mq_get(&mq, i)->control_type == i + 4);
+        assert_true(mqtt_mq_get(&mq, i)->packet_id == 111 * (i + 3));
+    }
+
+    /* remove the last two */
+    mqtt_mq_get(&mq, 0)->state = MQTT_QUEUED_COMPLETE;
+    mqtt_mq_get(&mq, 1)->state = MQTT_QUEUED_COMPLETE;
+    mqtt_mq_clean(&mq); 
+    assert_true(mqtt_mq_length(&mq) == 0);
+    assert_true(mq.curr_sz == 32 + 3*QM_SZ);
+    assert_true((void*) mq.queue_tail == mq.mem_end);
+}
+
+static void TEST__utility__pid_lfsr(void **unused) {
+    struct mqtt_client client;
+    uint8_t send[256], recv[256];
+    mqtt_init(&client, -1, send, 256, recv, 256, NULL);
+    client.pid_lfsr = 163u;
+    uint32_t period = 0;
+    do {
+        __mqtt_next_pid(&client);
+        period++;
+    } while(client.pid_lfsr != 163u && client.pid_lfsr !=0);
+    assert_true(period == 65535u);
+}
+
+void publish_callback(void** state, struct mqtt_response_publish *publish) {
+    /*char *name = (char*) malloc(publish->topic_name_size + 1);
+    memcpy(name, publish->topic_name, publish->topic_name_size);
+    name[publish->topic_name_size] = '\0';
+    printf("Received a PUBLISH(topic=%s, DUP=%d, QOS=%d, RETAIN=%d, pid=%d) from the broker. Data='%s'\n", 
+           name, publish->dup_flag, publish->qos_level, publish->retain_flag, publish->packet_id,
+           (const char*) (publish->application_message)
+    );
+    free(name);*/
+    **(int**)state += 1;
+}
+
+static void TEST__api__connect_ping_disconnect(void **unused) {
+    uint8_t sendmem[2048];
+    uint8_t recvmem[1024];
+    ssize_t rv;
+    struct mqtt_client client;
+
+    int sockfd = open_nb_socket(addr, port);
+
+    /* initialize */
+    mqtt_init(&client, sockfd, sendmem, sizeof(sendmem), recvmem, sizeof(recvmem), publish_callback);
+
+    /* connect */
+    assert_true(mqtt_connect(&client, "liam-123", NULL, NULL, 0, NULL, NULL, 0, 30) > 0);
+    assert_true(__mqtt_send(&client) > 0);
+    while(mqtt_mq_length(&client.mq) > 0) {
+        assert_true(__mqtt_recv(&client) > 0);
+        mqtt_mq_clean(&client.mq);
+        usleep(10000);
+    }
+
+    /* ping */
+    assert_true(mqtt_ping(&client) > 0);
+    while(mqtt_mq_length(&client.mq) > 0) {
+        rv = __mqtt_send(&client);
+        if (rv <= 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        rv = __mqtt_recv(&client);
+        if (rv <= 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        mqtt_mq_clean(&client.mq);
+        usleep(10000);
+    }
+
+    /* disconnect */
+    assert_true(client.error == MQTT_OK);
+    assert_true(mqtt_disconnect(&client) > 0);
+    assert_true(__mqtt_send(&client) > 0);
+}
+
+static void TEST__api__publish_subscribe__single(void **unused) {
+    uint8_t sendmem1[2048], sendmem2[2048];
+    uint8_t recvmem1[1024], recvmem2[1024];
+    struct mqtt_client sender, receiver;
+
+    int state = 0;
+
+    int sockfd = open_nb_socket(addr, port);
+    mqtt_init(&sender, sockfd, sendmem1, sizeof(sendmem1), recvmem1, sizeof(recvmem1), publish_callback);
+
+    sockfd = open_nb_socket(addr, port);
+    mqtt_init(&receiver, sockfd, sendmem2, sizeof(sendmem2), recvmem2, sizeof(recvmem2), publish_callback);
+    receiver.publish_response_callback_state = &state;
+
+    /* connect both */
+    assert_true(mqtt_connect(&sender, "liam-123", NULL, NULL, 0, NULL, NULL, 0, 30) > 0);
+    assert_true(mqtt_connect(&receiver, "liam-234", NULL, NULL, 0, NULL, NULL, 0, 30) > 0);
+    assert_true(__mqtt_send(&sender) > 0);
+    assert_true(__mqtt_send(&receiver) > 0);
+    while(mqtt_mq_length(&sender.mq) > 0 || mqtt_mq_length(&receiver.mq) > 0) {
+        assert_true(__mqtt_recv(&sender) > 0);
+        mqtt_mq_clean(&sender.mq);
+        assert_true(__mqtt_recv(&receiver) > 0);
+        mqtt_mq_clean(&receiver.mq);
+        usleep(10000);
+    }
+
+    /* subscribe receiver*/
+    assert_true(mqtt_subscribe(&receiver, "liam-test-topic", 2) > 0);
+    assert_true(__mqtt_send(&receiver) > 0);
+    while(mqtt_mq_length(&receiver.mq) > 0) {
+        assert_true(__mqtt_recv(&receiver) > 0);
+        mqtt_mq_clean(&receiver.mq);
+        usleep(10000);
+    }
+
+    /* publish from sender */
+    assert_true(mqtt_publish(&sender, "liam-test-topic", "data", 5, MQTT_PUBLISH_QOS_0) > 0);
+    assert_true(__mqtt_send(&sender) > 0);
+
+    time_t start = time(NULL);
+    while(state == 0 && time(NULL) < start + 10) {
+        assert_true(__mqtt_recv(&receiver) > 0);        
+        usleep(10000);
+    }
+
+    assert_true(state == 1);
+
+    /* disconnect */
+    assert_true(sender.error == MQTT_OK);
+    assert_true(receiver.error == MQTT_OK);
+    assert_true(mqtt_disconnect(&sender) > 0);
+    assert_true(mqtt_disconnect(&receiver) > 0);
+    assert_true(__mqtt_send(&sender) > 0);
+    assert_true(__mqtt_send(&receiver) > 0);
+}
+
+
+#define TEST_PACKET_SIZE (149)
+#define TEST_DATA_SIZE (128)
+static void TEST__api__publish_subscribe__multiple(void **unused) {
+    uint8_t sendmem1[TEST_PACKET_SIZE*4 + sizeof(struct mqtt_queued_message)*4], 
+            sendmem2[TEST_PACKET_SIZE*4 + sizeof(struct mqtt_queued_message)*4];
+    uint8_t recvmem1[TEST_PACKET_SIZE], recvmem2[TEST_PACKET_SIZE];
+    struct mqtt_client sender, receiver;
+    ssize_t rv;
+
+    int state = 0;
+
+    /* initialize sender */
+    int sockfd = open_nb_socket(addr, port);
+    mqtt_init(&sender, sockfd, sendmem1, sizeof(sendmem1), recvmem1, sizeof(recvmem1), publish_callback);
+
+    sockfd = open_nb_socket(addr, port);
+    mqtt_init(&receiver, sockfd, sendmem2, sizeof(sendmem2), recvmem2, sizeof(recvmem2), publish_callback);
+    receiver.publish_response_callback_state = &state;
+
+    /* connect both */
+    if ((rv = mqtt_connect(&sender, "liam-123", NULL, NULL, 0, NULL, NULL, MQTT_CONNECT_CLEAN_SESSION, 30)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_connect(&receiver, "liam-234", NULL, NULL, 0, NULL, NULL, MQTT_CONNECT_CLEAN_SESSION, 30)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&sender)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&receiver)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    while(mqtt_mq_length(&sender.mq) > 0 || mqtt_mq_length(&receiver.mq) > 0) {
+        if ((rv = __mqtt_recv(&sender)) <= 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(rv  > 0);
+        }
+        mqtt_mq_clean(&sender.mq);
+        if ((rv = __mqtt_recv(&receiver)) <= 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(rv  > 0);
+        }
+        mqtt_mq_clean(&receiver.mq);
+        usleep(10000);
+    }
+
+    state = 0;
+
+    /* publish with retain */
+    if ((rv = mqtt_publish(&sender, "liam-test-ret1", "this was initial retain with qos 1", TEST_DATA_SIZE, MQTT_PUBLISH_QOS_1 | MQTT_PUBLISH_RETAIN)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&sender)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+
+    /* subscribe receiver*/
+    if ((rv = mqtt_subscribe(&receiver, "liam-test-qos0", 0)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_subscribe(&receiver, "liam-test-qos1", 1)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_subscribe(&receiver, "liam-test-qos2", 2)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_subscribe(&receiver, "liam-test-ret1", 2)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&receiver)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+
+    /* wait for retained publish and receiver and sender have 0 length mq's */
+    time_t start = time(NULL);
+    while(start + 10 > time(NULL)  && (state < 1 || mqtt_mq_length(&receiver.mq) > 0 || mqtt_mq_length(&sender.mq) > 0)) {
+        if ((rv = mqtt_sync(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        mqtt_mq_clean(&receiver.mq);
+        if ((rv = mqtt_sync(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        mqtt_mq_clean(&sender.mq);
+        usleep(10000);
+    }
+
+    /* make sure that we publish was called */
+    assert_true(mqtt_mq_length(&receiver.mq) == 0);
+    assert_true(mqtt_mq_length(&sender.mq) == 0);
+    assert_true(state == 1);
+
+    /* now publish 4 perfect sized messages */
+    if ((rv = mqtt_publish(&sender, "liam-test-ret1", "retain with qos1", TEST_DATA_SIZE, MQTT_PUBLISH_QOS_1)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_publish(&sender, "liam-test-qos0", "test with qos 0", TEST_DATA_SIZE, MQTT_PUBLISH_QOS_0)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_publish(&sender, "liam-test-qos1", "test with qos 1", TEST_DATA_SIZE, MQTT_PUBLISH_QOS_1)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_publish(&sender, "liam-test-qos2", "test with qos 2", TEST_DATA_SIZE, MQTT_PUBLISH_QOS_2)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&sender)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    assert_true(sender.error == MQTT_OK);
+    assert_true(sender.mq.curr_sz == 0);
+
+    /* give 2 seconds for sending and receiving (also don't manually clean) */
+    start = time(NULL);
+    while(time(NULL) < start + 8) {
+        if ((rv = __mqtt_recv(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_recv(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_send(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_send(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        usleep(10000);
+    }
+
+    if (state != 5) {
+        printf("error: state == %d\n", state);
+        assert_true(state == 5);
+    }
+
+    /* test unsubscribe */
+    if ((rv = mqtt_unsubscribe(&receiver, "liam-test-qos1")) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+
+    /*sleep for 2 seconds while unsubscribe is sending */ 
+    start = time(NULL);
+    while(time(NULL) < start + 2) {
+        if ((rv = __mqtt_recv(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_recv(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_send(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_send(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        usleep(10000);
+    }
+    /* publish qos1 (should be received by receiver) */
+    if ((rv = mqtt_publish(&sender, "liam-test-qos1", "test with qos 1", TEST_DATA_SIZE, MQTT_PUBLISH_QOS_1)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    /*sleep for 2 seconds to give the publish a chance  */ 
+    start = time(NULL);
+    while(time(NULL) < start + 2) {
+        if ((rv = __mqtt_recv(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_recv(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_send(&receiver)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        if ((rv = __mqtt_send(&sender)) < 0) {
+            printf("error: %s\n", mqtt_error_str(rv));
+            assert_true(0);
+        }
+        usleep(10000);
+    }
+
+    /* check that the callback wasn't called */
+    if (state != 5) {
+        printf("error: state == %d\n", state);
+        assert_true(state == 5);
+    }
+
+    /* disconnect */
+    assert_true(sender.error == MQTT_OK);
+    assert_true(receiver.error == MQTT_OK);
+    if ((rv = mqtt_disconnect(&sender)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = mqtt_disconnect(&receiver)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&sender)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+    if ((rv = __mqtt_send(&receiver)) <= 0) {
+        printf("error: %s\n", mqtt_error_str(rv));
+        assert_true(rv  > 0);
+    }
+}
+
+int main(int argc, const char *argv[]) {
+    int rv = 0;
+
+    /* get address (argv[1] if present) */
+    if (argc > 1) {
+        addr = argv[1];
+    }
+
+    /* get port number (argv[2] if present) */
+    if (argc > 2) {
+        port = argv[2];
+    }
+
+    printf("Staring MQTT-C unit-tests.\n");
+    printf("Using broker: \"%s:%s\"\n\n", addr, port);
+
+#if defined(WIN32)
+    WSADATA wsaData;
+    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
+    if (iResult != NO_ERROR) {
+        fprintf(stderr, "Failed to init sockets: %i\n", iResult);
+        return iResult;
+    }
+#endif
+
+    printf("[MQTT Packet Serialization/Deserialization Tests]\n");
+    const struct CMUnitTest framing_tests[] = {
+        cmocka_unit_test(TEST__framing__fixed_header),
+        cmocka_unit_test(TEST__framing__connect),
+        cmocka_unit_test(TEST__framing__connack),
+        cmocka_unit_test(TEST__framing__publish),
+        cmocka_unit_test(TEST__framing__pubxxx),
+        cmocka_unit_test(TEST__framing__subscribe),
+        cmocka_unit_test(TEST__framing__suback),
+        cmocka_unit_test(TEST__framing__unsubscribe),
+        cmocka_unit_test(TEST__framing__unsuback),
+        cmocka_unit_test(TEST__framing__ping),
+        cmocka_unit_test(TEST__framing__disconnect),
+    };
+
+    rv |= cmocka_run_group_tests(framing_tests, NULL, NULL);
+
+    printf("\n[MQTT-C Utilities Tests]\n");
+    const struct CMUnitTest util_tests[] = {
+        cmocka_unit_test(TEST__utility__message_queue),
+        cmocka_unit_test(TEST__utility__pid_lfsr),
+        cmocka_unit_test(TEST__utility__connect_disconnect),
+        cmocka_unit_test(TEST__utility__ping),
+    };
+
+    rv |= cmocka_run_group_tests(util_tests, NULL, NULL);
+
+    printf("\n[MQTT-C API Tests]\n");
+    const struct CMUnitTest api_tests[] = {
+        cmocka_unit_test(TEST__api__connect_ping_disconnect),
+        cmocka_unit_test(TEST__api__publish_subscribe__single),
+        cmocka_unit_test(TEST__api__publish_subscribe__multiple),
+    };
+
+    rv |= cmocka_run_group_tests(api_tests, NULL, NULL);
+
+#if defined(WIN32)
+    WSACleanup();
+#endif
+
+    return rv;
+}

documentation/webdocs/markdowndocs/connector-ch.md

@@ -1209,13 +1209,51 @@ TDengine在Window系统上提供的API与Linux系统是相同的， 应用程序
 其中，最常用的文件列出如下：
 
 + Client可执行文件: /usr/local/taos/bin/taos 软连接到 /usr/local/bin/taos
+
 + 配置文件: /usr/local/taos/cfg/taos.cfg 软连接到 /etc/taos/taos.cfg
+
 + 驱动程序目录: /usr/local/taos/driver/libtaos.1.6.5.1.dylib 软连接到 /usr/local/lib/libtaos.dylib
+
 + 驱动程序头文件: /usr/local/taos/include/taos.h 软连接到 /usr/local/include/taos.h
+
 + 日志目录（第一次运行程序时生成）：~/TDengineLog
 
   
 
+
+## MQTT客户端
+
+MQTT客户端实现了订阅MQTT Broker的特定Topic将Json数据进行转换入库的功能，任何终端只要将数据发给特定的Topic 即可,不用再编写转换器或者数据解析程序。如果终端量大，需要 Mqtt Broker 群集，这里不再详述。
+
+#### 如何配置？
+
+首先需要在 taos.cfg 中打开配置项 mqtt 用来启用， 再通过修改 mqttBrokerAddress  的值来配置连接，格式为: 
+
+> mqtt://username:password@hostname:port/path/
+
+ 例如:
+
+> mqtt://127.0.0.1:1883/taos/  mqtt://root@kissme@127.0.0.1:1883/taos/
+
+
+#### Topic 格式说明
+
+ Mqtt 的topic格式为
+
+> /<path>/<token>/<db name>/<table name>/
+
+因此TDengine的Mqtt客户端会订阅:
+
+> /taos/+/+/+/+/  
+
+例如: 
+
+>  /taos/token/db/t/  
+
+注意: 测试时如果需要使用到Mqtt Broker 推荐使用 [mosquitto](http://mosquitto.org/) ，客户端可以使用  [MQTT.fx ](http://www.jensd.de/)
+
+
+
 [1]: https://search.maven.org/artifact/com.taosdata.jdbc/taos-jdbcdriver
 [2]: https://mvnrepository.com/artifact/com.taosdata.jdbc/taos-jdbcdriver
 [3]: https://github.com/taosdata/TDengine

packaging/cfg/taos.cfg

@@ -166,6 +166,15 @@
 # start system monitor module
 # monitor               1
 
+# start http service
+# mqtt                  0
+
+# mqtt uri  
+# mqttBrokerAddress  mqtt://username:password@hostname:1883/taos/
+
+# mqtt client name 
+# mqttBrokerClientId  taos_mqtt
+
 # maximum number of rows returned by the restful interface
 # restfulRowLimit       10240
 
@@ -244,5 +253,8 @@
 # debug flag for system monitor 
 # monitorDebugFlag      131
 
+#debug flag for mqtt client 
+# mqttDebugFlag         131
+
 # debug flag for TAOS TIMER
 # tmrDebugFlag          131

src/common/inc/tglobal.h

@@ -94,6 +94,10 @@ extern int32_t tsMaxTables;
 extern char tsDefaultDB[];
 extern char tsDefaultUser[];
 extern char tsDefaultPass[];
+
+extern char tsMqttBrokerAddress[];
+extern char tsMqttBrokerClientId[];
+
 extern int32_t tsMaxConnections;
 
 extern int32_t tsBalanceInterval;

src/common/src/tglobal.c

@@ -199,6 +199,8 @@ int32_t tsMonitorInterval = 30;  // seconds
 char tsTimezone[64] = {0};
 char tsLocale[TSDB_LOCALE_LEN] = {0};
 char tsCharset[TSDB_LOCALE_LEN] = {0};  // default encode string
+char tsMqttBrokerAddress[128] = {0}; 
+char tsMqttBrokerClientId[128] = {0};
 
 int32_t tsMaxBinaryDisplayWidth = 30;
 
@@ -729,6 +731,26 @@ static void doInitGlobalConfig() {
   cfg.unitType = TAOS_CFG_UTYPE_NONE;
   taosInitConfigOption(cfg);
 
+  cfg.option = "mqttBrokerAddress";
+  cfg.ptr = tsMqttBrokerAddress;
+  cfg.valType = TAOS_CFG_VTYPE_STRING;
+  cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT | TSDB_CFG_CTYPE_B_NOT_PRINT;
+  cfg.minValue = 0;
+  cfg.maxValue = 0;
+  cfg.ptrLength = 126;
+  cfg.unitType = TAOS_CFG_UTYPE_NONE;
+  taosInitConfigOption(cfg);
+
+  cfg.option = "mqttBrokerClientId";
+  cfg.ptr = tsMqttBrokerClientId;
+  cfg.valType = TAOS_CFG_VTYPE_STRING;
+  cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT | TSDB_CFG_CTYPE_B_NOT_PRINT;
+  cfg.minValue = 0;
+  cfg.maxValue = 0;
+  cfg.ptrLength = 126;
+  cfg.unitType = TAOS_CFG_UTYPE_NONE;
+  taosInitConfigOption(cfg);
+ 
   // socket type; udp by default
   cfg.option = "sockettype";
   cfg.ptr = tsSocketType;

src/dnode/src/dnodeModule.c

@@ -19,7 +19,7 @@
 #include "tglobal.h"
 #include "mnode.h"
 #include "http.h"
-#include "mqtt.h"
+#include "tmqtt.h"
 #include "monitor.h"
 #include "dnodeInt.h"
 #include "dnodeModule.h"

src/inc/mqtt.h → src/inc/tmqtt.h

@@ -19,10 +19,7 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-
 #include <stdint.h>
-
-int32_t mqttGetReqCount();
 int32_t mqttInitSystem();
 int32_t mqttStartSystem();
 void mqttStopSystem();

src/plugins/mqtt/CMakeLists.txt

@@ -7,16 +7,16 @@ IF ((TD_LINUX_64) OR (TD_LINUX_32 AND TD_ARM))
   INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/src/util/inc)
   INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/src/query/inc)
   INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/src/common/inc)
-  INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/deps/zlib-1.2.11/inc)
   INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/deps/cJson/inc)
-  INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/deps/lz4/inc)
+  INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/deps/MQTT-C/include)
+  INCLUDE_DIRECTORIES(${TD_COMMUNITY_DIR}/deps/MQTT-C/examples/templates)
   INCLUDE_DIRECTORIES(${TD_OS_DIR}/inc)
   INCLUDE_DIRECTORIES(inc)
   AUX_SOURCE_DIRECTORY(src SRC)
   ADD_LIBRARY(mqtt ${SRC})
-  TARGET_LINK_LIBRARIES(mqtt taos_static z)
+  TARGET_LINK_LIBRARIES(mqtt taos_static cJson mqttc)
 
   IF (TD_ADMIN)
-    TARGET_LINK_LIBRARIES(mqtt admin)
+    TARGET_LINK_LIBRARIES(mqtt admin cJson)
   ENDIF ()
 ENDIF ()

src/plugins/mqtt/inc/mqttInit.h

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TDENGINE_MQTT_INIT_H
+#define TDENGINE_MQTT_INIT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @file
+ * A simple subscriber program that performs automatic reconnections.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "mqtt.h"
+#include "taos.h"
+
+/**
+ * @brief A structure that I will use to keep track of some data needed
+ *        to setup the connection to the broker.
+ *
+ * An instance of this struct will be created in my \c main(). Then, whenever
+ * \ref mqttReconnectClient is called, this instance will be passed.
+ */
+struct reconnect_state_t {
+  char*    hostname;
+  char*    port;
+  char*    topic;
+  char*    client_id;
+  char*    user_name;
+  char*    password;
+  uint8_t* sendbuf;
+  size_t   sendbufsz;
+  uint8_t* recvbuf;
+  size_t   recvbufsz;
+};
+
+/**
+ * @brief My reconnect callback. It will reestablish the connection whenever
+ *        an error occurs.
+ */
+void mqttReconnectClient(struct mqtt_client* client, void** reconnect_state_vptr);
+
+/**
+ * @brief The function will be called whenever a PUBLISH message is received.
+ */
+void mqtt_PublishCallback(void** unused, struct mqtt_response_publish* published);
+
+/**
+ * @brief The client's refresher. This function triggers back-end routines to
+ *        handle ingress/egress traffic to the broker.
+ *
+ * @note All this function needs to do is call \ref __mqtt_recv and
+ *       \ref __mqtt_send every so often. I've picked 100 ms meaning that
+ *       client ingress/egress traffic will be handled every 100 ms.
+ */
+void* mqttClientRefresher(void* client);
+
+/**
+ * @brief Safelty closes the \p sockfd and cancels the \p client_daemon before \c exit.
+ */
+
+void mqttCleanup(int status, int sockfd, pthread_t* client_daemon);
+void mqttInitConnCb(void* param, TAOS_RES* result, int32_t code);
+void mqttQueryInsertCallback(void* param, TAOS_RES* result, int32_t code);
+#define QOS 1
+#define TIMEOUT 10000L
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/plugins/mqtt/inc/mqttPayload.h

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TDENGINE_MQTT_PLYLOAD_H
+#define TDENGINE_MQTT_PLYLOAD_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+char  split(char str[], char delims[], char** p_p_cmd_part, int max);
+char* converJsonToSql(char* json, char* _dbname, char* _tablename);
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/plugins/mqtt/inc/mqttSystem.h

@@ -18,15 +18,11 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-
 #include <stdint.h>
-
-int32_t mqttGetReqCount();
 int32_t mqttInitSystem();
 int32_t mqttStartSystem();
 void    mqttStopSystem();
 void    mqttCleanUpSystem();
- 
 #ifdef __cplusplus
 }
 #endif

src/plugins/mqtt/src/mqttPayload.c

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define _DEFAULT_SOURCE
+#include "mqttPayload.h"
+#include "cJSON.h"
+#include "string.h"
+#include "taos.h"
+#include "mqttLog.h"
+#include "os.h"
+char split(char str[], char delims[], char** p_p_cmd_part, int max) {
+  char*  token = strtok(str, delims);
+  char   part_index = 0;
+  char** tmp_part = p_p_cmd_part;
+  while (token) {
+    *tmp_part++ = token;
+    token = strtok(NULL, delims);
+    part_index++;
+    if (part_index >= max) break;
+  }
+  return part_index;
+}
+
+char* converJsonToSql(char* json, char* _dbname, char* _tablename) {
+  cJSON* jPlayload = cJSON_Parse(json);
+  char   _names[102400] = {0};
+  char   _values[102400] = {0};
+  int    i = 0;
+  int    count = cJSON_GetArraySize(jPlayload);
+  for (; i < count; i++)  
+  {
+    cJSON* item = cJSON_GetArrayItem(jPlayload, i);
+    if (cJSON_Object == item->type) {
+      mqttPrint("The item '%s' is not supported", item->string);
+    } else {
+      strcat(_names, item->string);
+      if (i < count - 1) {
+        strcat(_names, ",");
+      }
+      char* __value_json = cJSON_Print(item);
+      strcat(_values, __value_json);
+      free(__value_json);
+      if (i < count - 1) {
+        strcat(_values, ",");
+      }
+    }
+  }
+  cJSON_free(jPlayload);
+  int   sqllen = strlen(_names) + strlen(_values) + strlen(_dbname) + strlen(_tablename) + 1024;
+  char* _sql = calloc(1, sqllen);
+  sprintf(_sql, "INSERT INTO %s.%s (%s) VALUES(%s);", _dbname, _tablename, _names, _values);
+  return _sql;
+}
\ No newline at end of file

src/plugins/mqtt/src/mqttSystem.c

@@ -14,30 +14,218 @@
  */
 
 #define _DEFAULT_SOURCE
-#include "mqttSystem.h"
+
+#include "cJSON.h"
 #include "mqtt.h"
+#include "mqttInit.h"
 #include "mqttLog.h"
+#include "mqttPayload.h"
 #include "os.h"
+#include "posix_sockets.h"
+#include "string.h"
 #include "taos.h"
 #include "tglobal.h"
+#include "tmqtt.h"
+#include "tsclient.h"
 #include "tsocket.h"
 #include "ttimer.h"
+#include "mqttSystem.h"
+struct mqtt_client       mqttClient = {0};
+pthread_t                clientDaemonThread = {0};
+void*                    mqttConnect=NULL;
+struct reconnect_state_t recntStatus = {0};
+char*                    topicPath=NULL;
+int                      mttIsRuning = 1;
+
+int32_t mqttInitSystem() {
+  int   rc = 0;
+  uint8_t sendbuf[2048];
+  uint8_t recvbuf[1024];
+  recntStatus.sendbuf = sendbuf;
+  recntStatus.sendbufsz = sizeof(sendbuf);
+  recntStatus.recvbuf = recvbuf;
+  recntStatus.recvbufsz = sizeof(recvbuf);
+  char* url = tsMqttBrokerAddress;
+  recntStatus.user_name = strstr(url, "@") != NULL ? strbetween(url, "//", ":") : NULL;
+  recntStatus.password = strstr(url, "@") != NULL ? strbetween(strstr(url, recntStatus.user_name), ":", "@") : NULL;
+
+  if (strlen(url) == 0) {
+    mqttError("failed to initialize mqtt module, reason: url is null");
+    return rc;
+  }
+
+  if (strstr(url, "@") != NULL) {
+    recntStatus.hostname = strbetween(url, "@", ":");
+  } else if (strstr(strstr(url, "://") + 3, ":") != NULL) {
+    recntStatus.hostname = strbetween(url, "//", ":");
+
+  } else {
+    recntStatus.hostname = strbetween(url, "//", "/");
+  }
 
-int32_t mqttGetReqCount() { return 0; }
-int     mqttInitSystem() {
-  mqttPrint("mqttInitSystem");
-  return 0;
+  char* _begin_hostname = strstr(url, recntStatus.hostname);
+  if (strstr(_begin_hostname, ":") != NULL) {
+    recntStatus.port = strbetween(_begin_hostname, ":", "/");
+  } else {
+    recntStatus.port = strbetween("'1883'", "'", "'");
+  }
+
+  topicPath = strbetween(strstr(url, strstr(_begin_hostname, ":") != NULL ? recntStatus.port : recntStatus.hostname),
+                         "/", "/");
+  char* _topic = "+/+/+/";
+  int   _tpsize = strlen(topicPath) + strlen(_topic) + 1;
+  recntStatus.topic = calloc(1, _tpsize);
+  sprintf(recntStatus.topic, "/%s/%s", topicPath, _topic);
+  recntStatus.client_id = strlen(tsMqttBrokerClientId) < 3 ? tsMqttBrokerClientId : "taos_mqtt";
+  mqttConnect = NULL;
+  return rc;
 }
 
-int mqttStartSystem() {
-  mqttPrint("mqttStartSystem");
-  return 0;
+int32_t mqttStartSystem() {
+  int rc = 0;
+  if (recntStatus.user_name != NULL && recntStatus.password != NULL) {
+    mqttPrint("connecting to  mqtt://%s:%s@%s:%s/%s/", recntStatus.user_name, recntStatus.password,
+              recntStatus.hostname, recntStatus.port, topicPath);
+  } else if (recntStatus.user_name != NULL && recntStatus.password == NULL) {
+    mqttPrint("connecting to  mqtt://%s@%s:%s/%s/", recntStatus.user_name, recntStatus.hostname, recntStatus.port,
+              topicPath);
+  }
+
+  mqtt_init_reconnect(&mqttClient, mqttReconnectClient, &recntStatus, mqtt_PublishCallback);
+  if (pthread_create(&clientDaemonThread, NULL, mqttClientRefresher, &mqttClient)) {
+    mqttError("Failed to start client daemon.");
+    mqttCleanup(EXIT_FAILURE, -1, NULL);
+    rc = -1;
+  } else {
+    mqttPrint("listening for '%s' messages.", recntStatus.topic);
+  }
+  return rc;
 }
 
 void mqttStopSystem() {
-	mqttPrint("mqttStopSystem");
+  mqttClient.error = MQTT_ERROR_SOCKET_ERROR;
+  mttIsRuning = 0;
+  usleep(300000U);
+  mqttCleanup(EXIT_SUCCESS, mqttClient.socketfd, &clientDaemonThread);
+  mqttPrint("mqtt is stoped");
 }
 
 void mqttCleanUpSystem() {
-	mqttPrint("mqttCleanUpSystem");
+  mqttPrint("starting to clean  up mqtt");
+  free(recntStatus.user_name);
+  free(recntStatus.password);
+  free(recntStatus.hostname);
+  free(recntStatus.port);
+  free(recntStatus.topic);
+  free(topicPath);
+  mqttPrint("mqtt is cleaned up");
+}
+
+void mqtt_PublishCallback(void** unused, struct mqtt_response_publish* published) {
+  mqttPrint("mqtt_PublishCallback");
+  /* note that published->topic_name is NOT null-terminated (here we'll change it to a c-string) */
+  char* topic_name = (char*)malloc(published->topic_name_size + 1);
+  memcpy(topic_name, published->topic_name, published->topic_name_size);
+  topic_name[published->topic_name_size] = '\0';
+  mqttPrint("Received publish('%s'): %s", topic_name, (const char*)published->application_message);
+  char _token[128] = {0};
+  char _dbname[128] = {0};
+  char _tablename[128] = {0};
+  if (mqttConnect == NULL) {
+    mqttPrint("connect database");
+    taos_connect_a(NULL, "_root", tsInternalPass, "", 0, mqttInitConnCb, &mqttClient, &mqttConnect);
+  }
+  if (topic_name[1]=='/' &&  strncmp((char*)&topic_name[1], topicPath, strlen(topicPath)) == 0) {
+    char* p_p_cmd_part[5] = {0};
+    char  copystr[1024] = {0};
+    strncpy(copystr, topic_name, MIN(1024, published->topic_name_size));
+    char part_index = split(copystr, "/", p_p_cmd_part, 10);
+    if (part_index < 4) {
+      mqttError("The topic %s is't format '/path/token/dbname/table name/'. for expmle: '/taos/token/db/t'", topic_name);
+    } else {
+      strncpy(_token, p_p_cmd_part[1], 127);
+      strncpy(_dbname, p_p_cmd_part[2], 127);
+      strncpy(_tablename, p_p_cmd_part[3], 127);
+      mqttPrint("part count=%d,access token:%s,database name:%s, table name:%s", part_index, _token, _dbname,
+                _tablename);
+
+      if (mqttConnect != NULL) {
+        char* _sql = converJsonToSql((char*)published->application_message, _dbname, _tablename);
+        mqttPrint("query:%s", _sql);
+        taos_query_a(mqttConnect, _sql, mqttQueryInsertCallback, &mqttClient);
+        mqttPrint("free sql:%s", _sql);
+        free(_sql);
+      }
+    }
+  }
+  free(topic_name);
+}
+
+void* mqttClientRefresher(void* client) {
+  while (mttIsRuning) {
+    mqtt_sync((struct mqtt_client*)client);
+    usleep(100000U);
+  }
+  mqttPrint("Exit  mqttClientRefresher");
+  return NULL;
+}
+
+void mqttCleanup(int status, int sockfd, pthread_t* client_daemon) {
+  mqttPrint("mqttCleanup");
+  if (sockfd != -1) close(sockfd);
+  if (client_daemon != NULL) pthread_cancel(*client_daemon);
+}
+
+void mqttInitConnCb(void* param, TAOS_RES* result, int32_t code) {
+  if (code < 0) {
+    mqttError("mqtt:%d, connect to database failed, reason:%s", code, tstrerror(code));
+    taos_close(mqttConnect);
+    mqttConnect = NULL;
+    return;
+  }
+  mqttTrace("mqtt:%d, connect to database success, reason:%s", code, tstrerror(code));
+}
+
+void mqttQueryInsertCallback(void* param, TAOS_RES* result, int32_t code) {
+  if (code < 0) {
+    mqttError("mqtt:%d, save data failed, code:%s", code, tstrerror(code));
+  } else if (code == 0) {
+    mqttError("mqtt:%d, save data failed, affect rows:%d", code, code);
+  } else {
+    mqttPrint("mqtt:%d, save data   success, code:%s", code, tstrerror(code));
+  }
+}
+
+void mqttReconnectClient(struct mqtt_client* client, void** reconnect_state_vptr) {
+  mqttPrint("mqttReconnectClient");
+  struct reconnect_state_t* reconnect_state = *((struct reconnect_state_t**)reconnect_state_vptr);
+
+  /* Close the clients socket if this isn't the initial reconnect call */
+  if (client->error != MQTT_ERROR_INITIAL_RECONNECT) {
+    close(client->socketfd);
+  }
+
+  /* Perform error handling here. */
+  if (client->error != MQTT_ERROR_INITIAL_RECONNECT) {
+    mqttError("mqttReconnectClient: called while client was in error state \"%s\"", mqtt_error_str(client->error));
+  }
+
+  /* Open a new socket. */
+  int sockfd = open_nb_socket(reconnect_state->hostname, reconnect_state->port);
+  if (sockfd == -1) {
+    mqttError("Failed to open socket: ");
+    mqttCleanup(EXIT_FAILURE, sockfd, NULL);
+  }
+
+  /* Reinitialize the client. */
+  mqtt_reinit(client, sockfd, reconnect_state->sendbuf, reconnect_state->sendbufsz, reconnect_state->recvbuf,
+              reconnect_state->recvbufsz);
+
+  /* Ensure we have a clean session */
+  uint8_t connect_flags = MQTT_CONNECT_CLEAN_SESSION;
+  /* Send connection request to the broker. */
+  mqtt_connect(client, reconnect_state->client_id, NULL, NULL, 0, reconnect_state->user_name, reconnect_state->password,connect_flags, 400);
+
+  /* Subscribe to the topic. */
+  mqtt_subscribe(client, reconnect_state->topic, 0);
 }
\ No newline at end of file

src/util/inc/tutil.h

@@ -125,6 +125,8 @@ int64_t strnatoi(char *num, int32_t len);
 
 char* strreplace(const char* str, const char* pattern, const char* rep);
 
+char *strbetween(char *string, char *begin, char *end);
+
 char *paGetToken(char *src, char **token, int32_t *tokenLen);
 
 void taosMsleep(int32_t mseconds);

src/util/src/tutil.c

@@ -331,6 +331,20 @@ char *strreplace(const char *str, const char *pattern, const char *rep) {
   return dest;
 }
 
+char *strbetween(char *string, char *begin, char *end) {
+  char *result = NULL;
+  char *_begin = strstr(string, begin);
+  if (_begin != NULL) {
+    char *_end = strstr(_begin + strlen(begin), end);
+    int   size = _end - _begin;
+    if (_end != NULL && size > 0) {
+      result = (char *)calloc(1, size);
+      memcpy(result, _begin + strlen(begin), size - +strlen(begin));
+    }
+  }
+  return result;
+}
+
 int32_t taosByteArrayToHexStr(char bytes[], int32_t len, char hexstr[]) {
   int32_t i;
   char    hexval[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

tests/script/sh/cfg.sh

@@ -33,8 +33,8 @@ SCRIPT_DIR=`dirname $0`
 cd $SCRIPT_DIR/../
 SCRIPT_DIR=`pwd`
 
-TDINTERNAL="TDinternal"
-if [[ "$SCRIPT_DIR" == *"$TDINTERNAL"* ]]; then
+IN_TDINTERNAL="community"
+if [[ "$SCRIPT_DIR" == *"$IN_TDINTERNAL"* ]]; then
   cd ../../..
 else
   cd ../../

tests/script/sh/clear.sh

@@ -36,8 +36,8 @@ cd $SCRIPT_DIR/../
 SCRIPT_DIR=`pwd`
 echo "SCRIPT_DIR: $SCRIPT_DIR" 
 
-TDINTERNAL="TDinternal"
-if [[ "$SCRIPT_DIR" == *"$TDINTERNAL"* ]]; then
+IN_TDINTERNAL="community"
+if [[ "$SCRIPT_DIR" == *"$IN_TDINTERNAL"* ]]; then
   cd ../../..
 else
   cd ../../

tests/script/sh/deploy.sh

@@ -31,8 +31,8 @@ cd $SCRIPT_DIR/../
 SCRIPT_DIR=`pwd`
 echo "SCRIPT_DIR: $SCRIPT_DIR" 
 
-TDINTERNAL="TDinternal"
-if [[ "$SCRIPT_DIR" == *"$TDINTERNAL"* ]]; then
+IN_TDINTERNAL="community"
+if [[ "$SCRIPT_DIR" == *"$IN_TDINTERNAL"* ]]; then
   cd ../../..
 else
   cd ../../

tests/script/sh/exec.sh

@@ -42,8 +42,8 @@ SCRIPT_DIR=`dirname $0`
 cd $SCRIPT_DIR/../
 SCRIPT_DIR=`pwd`
 
-TDINTERNAL="TDinternal"
-if [[ "$SCRIPT_DIR" == *"$TDINTERNAL"* ]]; then
+IN_TDINTERNAL="community"
+if [[ "$SCRIPT_DIR" == *"$IN_TDINTERNAL"* ]]; then
   cd ../../..
 else
   cd ../../

tests/script/sh/exec_tarbitrator.sh

@@ -39,8 +39,8 @@ SCRIPT_DIR=`dirname $0`
 cd $SCRIPT_DIR/../
 SCRIPT_DIR=`pwd`
 
-TDINTERNAL="TDinternal"
-if [[ "$SCRIPT_DIR" == *"$TDINTERNAL"* ]]; then
+IN_TDINTERNAL="community"
+if [[ "$SCRIPT_DIR" == *"$IN_TDINTERNAL"* ]]; then
   cd ../../..
 else
   cd ../../

tests/script/test.sh

@@ -41,8 +41,8 @@ cd .
 CODE_DIR=`dirname $0`
 CODE_DIR=`pwd`
 
-TDINTERNAL="TDinternal"
-if [[ "$CODE_DIR" == *"$TDINTERNAL"* ]]; then
+IN_TDINTERNAL="community"
+if [[ "$CODE_DIR" == *"$IN_TDINTERNAL"* ]]; then
   cd ../../..
 else
   cd ../../