* Discard optimized containers with negative counts in UBJSON/BJData (#3491,#3492,#3490)

* fix msvc error

* update unit tests for negative sized containers

* use a loop to test 0 ndarray dimension

* throw an error when count is negative, merge CHECK_THROW_AS and _WITH with _WITH_AS

* 👥 update contributor and sponsor list

* 🚧 document BJData format

* 🚧 document BJData format

* 📝 clarified documentation of [json.exception.parse_error.112]

* ✏ adjust titles

* 📝 add more examples

* 🚨 adjust warnings for index.md files

* 📝 add more examples

* 🔥 remove example for deprecated code

* 📝 add missing enum entry

* 📝 overwork table for binary formats

* ✅ add test to create table for binary formats

* 📝 fix wording in example

* 📝 add more examples

* Update iterators.md (#3481)

* ✨ add check for overloads to linter #3455

* 👥 update contributor list

* 📝 add more examples

* 📝 fix documentation

* 📝 add more examples

* 🎨 fix indentation

* 🔥 remove example for destructor

* 📝 overwork documentation

* Updated BJData documentation, #3464 (#3493)

* update bjdata.md for #3464

* Minor edit

* Fix URL typo

* Add info on demoting ND array to a 1-D optimized array when singleton dimension
Co-authored-by: NChaoqi Zhang <prncoprs@163.com>
Co-authored-by: NQianqian Fang <fangqq@gmail.com>

* change bjdata ndarray flag to detect negative size, fix https://github.com/nlohmann/json/issues/3475

* fix CI error

* fix CI on 32bit windows

* remove platform specific out_of_range error messages

* Incorporate suggestions from @nlohmann and @falbrechtskirchinger

* fix CI errors

* add coverage

* fix sax event order

* fix coverage

* 📝 document fuzzer usage

* 📝 address review comments

* Handle invalid BJData optimized type, fix #3461

* Update unit test to handle bjdata optimized array type error

* ⬆ Doctest 2.4.7

* 👷 add CI step for ICPC

* 👷 add CI step for ICPC

* 👷 add CI step for ICPC

* ⬇ downgrade to Doctest 2.4.6

* 👷 add CI step for ICPC

* 👷 add CI step for ICPC

* 👷 add CI step for ICPC

* 👷 add CI step for ICPC

* 👷 add CI step for ICPC

* 🔇 suppress warning #2196: routine is both "inline" and "noinline"

* Re-enable <filesystem> detection on ICPC

* Limit regression test for #3070 to Clang and GCC >=8.4

* Disable deprecation warnings on ICPC

* Disable regression test for #1647 on ICPC (C++20)

* Fix compilation failure of regression test for #3077 on ICPC

* Disable wstring unit test on ICPC

Fixes:
  error 913: invalid multibyte character sequence

* Add ICPC to README
Co-authored-by: NNiels Lohmann <mail@nlohmann.me>

* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests

* Add key_compare member to ordered_map

* Replace == with key_compare in ordered_map

* Expose the actual comparison function used by object_t

nlohmann::ordered_map uses a different comparison function than the one
provided via template parameter.
* Introduce a type trait to detect if object_t has a key_compare member.
* Rename object_comparator_t to default_object_comparator_t.
* Add object_comparator_t to be conditionally defined as
  object_t::key_compare, if available, or default_object_comparator_t
  otherwise.
* Update the documentation accordingly.
Co-authored-by: NNiels Lohmann <niels.lohmann@gmail.com>

* Add type traits to check if a type is usable as object key

Add type trait to check:
* if a type is a specialization of a template.
* if a type is a json_pointer.
* if a type is a basic_json::{const_,}iterator.
* if two types are comparable using a given comparison functor.
* if a type is comparable to basic_json::object_t::key_type.
* if a type has a member type is_transparent.
* if a type is usable as object key.
* if a type has an erase() function accepting a given KeyType.
Co-authored-by: NNiels Lohmann <niels.lohmann@gmail.com>

* Rework basic_json element access to accept more key types

Rework basic_json element access member functions and operators to
accept any type that meets the requirements defined by type trait
detail::is_usable_as_key_type.

Member functions and operators:
* at()
* operator[]
* value()
* erase()
* find()
* count()
* contains()

Update documentation to reflect these changes.

Add unit tests to excercise the new functions using std::string_view.
Co-authored-by: NNiels Lohmann <niels.lohmann@gmail.com>
Co-authored-by: NNiels Lohmann <niels.lohmann@gmail.com>

* support UBJSON-derived Binary JData (BJData) format

* fix Codacy warning

* partially fix VS compilation errors

* fix additional VS errors

* fix more VS compilation errors

* fix additional warnings and errors for clang and msvc

* add more tests to cover the new bjdata types

* add tests for optimized ndarray, improve coverage, fix clang/gcc warnings

* gcc warn useless conversion but msvc gives an error

* fix ci_test errors

* complete test coverage, fix ci_test errors

* add half precision error test

* fix No newline at end of file error by clang

* simplify endian condition, format unit-bjdata

* remove broken test due to alloc limit

* full coverage, I hope

* move bjdata new markers from default to the same level as ubjson markers

* fix ci errors, add tests for new bjdata switch structure

* make is_bjdata const after using initializer list

* remove the unwanted assert

* move is_bjdata to an optional param to write_ubjson

* pass use_bjdata via output adapter

* revert order to avoid msvc 2015 unreferenced formal param error

* update BJData Spect V1 Draft-2 URL after spec release

* amalgamate code

* code polishing following @gregmarr's feedback

* make use_bjdata a non-default parameter

* fix ci error, remove unwanted param comment

* encode and decode bjdata ndarray in jdata annotations, enable roundtrip tests

* partially fix ci errors, add tests to improve coverage

* polish patch to remove ci errors

* fix a ndarray dim vector condition

* fix clang tidy error

* add sax test cases for ndarray

* add additional sax event tests

* adjust sax event numbering

* fix sax tests

* ndarray can only be used with array containers, discard if used in object

* complete test coverage

* disable [{SHTFNZ in optimized type due to security risks in #2793 and hampered readability

* fix ci error

* move OutputIsLittleEndian from tparam to param to replace use_bjdata

* fix ci clang gcc error

* fix ci static analysis error

* update json_test_data to 3.1.0, enable file-based bjdata unit tests

* fix stack overflow error on msvc 2019 and 2022

* use https link, update sax_parse_error after rebase

* make input_format const and use initializer

* return bool for write_bjdata_ndarray

* test write_bjdata_ndarray return value as boolean

* fix ci error

* 📝 overwork macro documentation

* 📝 address review comments

* 🔧 add style check to Makefile

* 🙈 overwork .gitignore

* 📌 Pygments 2.12.0 is broken

* ✏ fix links

* 🚸 adjust output to cppcheck

* 📝 add titles to more admonitions

* ✏ fix typos

* 📝 document future behavior change

* Make exception context optional

Change exception context parameter to pointer and replace context with
nullptr where appropriate.

* Support escaping other string types

* Add string concatenation function

Add variadic concat() function for concatenating char *, char, and
string types.

* Replace string concatenations using + with concat()

* Template json_pointer on string type

Change json_pointer from being templated on basic_json to being
templated on string type.

* Add unit test for #3388

Closes #3388.

* Fix regression test for #2958

* Add backwards compatibility with json_pointer<basic_json>

* Update json_pointer docs

* Allow comparing different json_pointers

* Update version numbers

* Exclude std::any from implicit conversion

Fixes #3428 (MSVC) and silences compiler warning on GCC (-Wconversion).

* Exclude std::any from implicit conversion

Constrain from_json() overload for StringType to not accept json_ref and
require it to be assignable, instead of constructible, from
basic_json::string_t.

Re-enable C++14 tests on Clang <4.0.

Fixes #3171.
Fixes #3267.
Fixes #3312.
Fixes #3384.

* ⬆ use new CI image

* ⬆ use new CI image

* 🚨 suppress Clang-Tidy warnings

* 💚 use proper scan-build version

* 🚨 suppress Clang-Tidy warnings

* ⬆ use more recent GitHub actions

* 💚 add missing compiler

* 📝 update used compilers

* 🚨 fix duplicate inclusion

AppVeyor build VMs should provide at least two cores. Parallelize builds
and tests.
In addition, enable output on failure and disable verbose test output.

Restore the previously disabled check for regression #3070 on all
compilers but MSVC.

To summarize the issue:
Given namespace fs = std::filesystem.
On MSVC attempting to construct an fs::path from json results in an
ambiguous overload resolution because fs::path can be constructed from
both a std::string as well as another fs::path.
To the best of my knowledge there is no way to fix an ambiguous overload
situation involving a type we do not control and with json implicitly
converting to both std::string and fs::path.

Re-enabling the check where it compiles and keeping it disabled for MSVC
is the best we can do.

Closes #3377 and #3382.

* Report the right __cplusplus value for MSVC in basic_json meta()

* Run amalgamate

* Avoid clash with Arduino defines

* Arduino defines B0/B1 in "binary.h"
     #define B0 0
     #define B1 1
  This clashes with names of the template
  variables in conjuction

* Renaming them to "B" rather than "B1"
  Now it can be used as-is in Arduino projects

* Apply suggestions from code review

* Apply suggestions from code review
Co-authored-by: NDaniel Ansorregui <d.ansorregui@samsung.com>
Co-authored-by: NNiels Lohmann <niels.lohmann@gmail.com>

* Refactor assertion and adjust expected error message

* Refactor assertion and adjust expected error message

* Refactor assertion and remove redundant local variable

* Refactor assertion and remove redundant local variable

* Rename local variable

* Apply formatting

* Add missing check

* Refactor assertions in unit-algorithms.cpp

* Refactor assertions in unit-bson.cpp

* Refactor assertions in unit-cbor.cpp

* Refactor assertions in unit-class_const_iterator.cpp

* Refactor assertions in unit-class_iterator.cpp

* Refactor assertions in unit-class_parser.cpp

* Refactor assertions in unit-constructor1.cpp

* Refactor assertions in unit-convenience.cpp

* Refactor assertions in unit-conversions.cpp

* Refactor assertions in unit-deserialization.cpp

* Refactor assertions in unit-element_access1.cpp

* Refactor assertions in unit-element_access2.cpp

* Refactor assertions in unit-iterators1.cpp

* Refactor assertions in unit-iterators2.cpp

* Refactor assertions in unit-json_patch.cpp

* Refactor assertions in unit-json_pointer.cpp

* Refactor assertions in unit-modifiers.cpp

* Refactor assertions in unit-msgpack.cpp

* Refactor assertions in unit-reference_access.cpp

* Refactor assertions in unit-regression1.cpp

* Refactor assertions in unit-serialization.cpp

* Refactor assertions in unit-ubjson.cpp

* Refactor assertions in unit-unicode1.cpp

* Apply formatting

* Refactor unit test creation

Add functions for creating tests and to supply test- and
standard-specific build settings.

Raises minimum CMake version to 3.13 in test directory.

json_test_add_test_for(
    <file>
    MAIN <main>
    [CXX_STANDARDS <version_number>...] [FORCE])

Given a <file> unit-foo.cpp, produces

    test-foo_cpp<version_number>

if C++ standard <version_number> is supported by the compiler and
thesource file contains JSON_HAS_CPP_<version_number>.  Use FORCE to
create the test regardless of the file containing
JSON_HAS_CPP_<version_number>.  Test targets are linked against <main>.
CXX_STANDARDS defaults to "11".

json_test_set_test_options(
    all|<tests>
    [CXX_STANDARDS all|<args>...]
    [COMPILE_DEFINITIONS <args>...]
    [COMPILE_FEATURES <args>...]
    [COMPILE_OPTIONS <args>...]
    [LINK_LIBRARIES <args>...]
    [LINK_OPTIONS <args>...])

Supply test- and standard-specific build settings.
Specify multiple tests using a list e.g., "test-foo;test-bar".

Must be called BEFORE the test is created.

* Use CMAKE_MODULE_PATH

* Don't undef some macros if JSON_TEST_KEEP_MACROS is defined

* Use JSON_TEST_KEEP_MACROS

Incidentally enables the regression tests for #2546 and #3070.

A CHECK_THROWS_WITH_AS in #3070 was disabled which is tracked in #3377
and a line in from_json(..., std_fs::path&) was marked with LCOV_EXCL_LINE.

* Add three-way comparison feature test macro

* Disable broken comparison if JSON_HAS_THREE_WAY_COMPARISON

* Fix redefinition of inline constexpr statics

Redelcaration of inline constexpr static data members in namespace scope
was deprecated in C++17. Fixes -Werror=deprecated compilation failures.

* Fix more test build failures due to missing noexcept

* CI: update cmake_flags test to use CMake 3.13 in test directory

Also change default for JSON_BuildTests option to depend on CMake
version.

* CI: turn *_CXXFLAGS into CMake lists

* CI: use JSON_TestStandards to set CXX_STANDARD

* CI: pass extra CXXFLAGS to standards tests

Commit f28fc226 introduced const qualifiers on post-(inc-/dec-)rement
operators of iterators. These qualifiers prevent the use of basic_json
in place of std::ranges::range, which requires the post-increment
operator to be equality-preserving.

These changes appear to be the result of ICC compiler suggestions, and
no further explanation is discernible from the PR discussion (#858).
Further testing revealed, that clang-tidy also suggests adding const to
prevent "accidental mutation of a temporary object".

As an alternative, this commit partially reverts f28fc226, removing all
added const qualifiers from return types and adds lvalue reference
qualifiers to the operator member functions instead.

Unit tests ensure the operators remain equality-preserving and
accidental mutation of temporaries following post-(inc-/dec-)rement is
prohibited.

Fixes #3331.

* 🔧 use proper GCC binary

* 🔧 add more GCC warning flags

* ⚗ try fix from https://github.com/nlohmann/json/issues/3138#issuecomment-1015562666

* Fix custom allocator test build failures (C++20)

Allocator tests fail to compile in C++20 mode with clang+MS STL due
to missing copy constructors.

* Fix test build failures due to missing noexcept (gcc-12)

* alt_string has multiple member functions that should be marked noexcept.
* nlohmann::ordered_map constructors can be noexcept.

Compilation failures result from the warning flag -Werror=noexcept and
gcc-12.

* Disable broken comparison tests in C++20 mode
Co-authored-by: NNiels Lohmann <mail@nlohmann.me>

* Update macros.md

Typos, typos

One of the ordered_map constructors was incorrectly accepting a
std::initializer_list<T> instead of std::initializer_list<value_type>.

Add regression test.

Fixes #3343.

* 🔧 use FetchContent_MakeAvailable

* 💚 fix test names