core(persistence): fix writeRaw() / readRaw() struct support

- writeRaw(): support structs
- readRaw(): 'len' is buffer limit in bytes (documentation is fixed)

modules/core/include/opencv2/core/persistence.hpp

@@ -597,8 +597,8 @@ public:
     Usually it is more convenient to use operator `>>` instead of this method.
     @param fmt Specification of each array element. See @ref format_spec "format specification"
     @param vec Pointer to the destination array.
-    @param len Number of elements to read. If it is greater than number of remaining elements then all
-    of them will be read.
+    @param len Number of bytes to read (buffer size limit). If it is greater than number of
+               remaining elements then all of them will be read.
      */
     void readRaw( const String& fmt, uchar* vec, size_t len ) const;
 
@@ -668,11 +668,12 @@ public:
     Usually it is more convenient to use operator `>>` instead of this method.
     @param fmt Specification of each array element. See @ref format_spec "format specification"
     @param vec Pointer to the destination array.
-    @param maxCount Number of elements to read. If it is greater than number of remaining elements then
-    all of them will be read.
+    @param len Number of bytes to read (buffer size limit). If it is greater than number of
+               remaining elements then all of them will be read.
+
      */
     FileNodeIterator& readRaw( const String& fmt, uchar* vec,
-                               size_t maxCount=(size_t)INT_MAX );
+                               size_t len=(size_t)INT_MAX );
 
     struct SeqReader
     {

modules/core/src/persistence.cpp

@@ -145,7 +145,7 @@ CvGenericHash* cvCreateMap( int flags, int header_size, int elem_size, CvMemStor
     return map;
 }
 
-void icvParseError( CvFileStorage* fs, const char* func_name,
+void icvParseError(const CvFileStorage* fs, const char* func_name,
                const char* err_msg, const char* source_file, int source_line )
 {
     cv::String msg = cv::format("%s(%d): %s", fs->filename, fs->lineno, err_msg);

modules/core/src/persistence.hpp

@@ -262,7 +262,7 @@ void icvFSCreateCollection( CvFileStorage* fs, int tag, CvFileNode* collection )
 char* icvFSResizeWriteBuffer( CvFileStorage* fs, char* ptr, int len );
 int icvCalcStructSize( const char* dt, int initial_size );
 int icvCalcElemSize( const char* dt, int initial_size );
-void CV_NORETURN icvParseError( CvFileStorage* fs, const char* func_name, const char* err_msg, const char* source_file, int source_line );
+void CV_NORETURN icvParseError(const CvFileStorage* fs, const char* func_name, const char* err_msg, const char* source_file, int source_line);
 char* icvEncodeFormat( int elem_type, char* dt );
 int icvDecodeFormat( const char* dt, int* fmt_pairs, int max_len );
 int icvDecodeSimpleFormat( const char* dt );

modules/core/src/persistence_cpp.cpp

@@ -11,21 +11,6 @@
 namespace cv
 {
 
-static void getElemSize( const String& fmt, size_t& elemSize, size_t& cn )
-{
-    const char* dt = fmt.c_str();
-    cn = 1;
-    if( cv_isdigit(dt[0]) )
-    {
-        cn = dt[0] - '0';
-        dt++;
-    }
-    char c = dt[0];
-    elemSize = cn*(c == 'u' || c == 'c' ? sizeof(uchar) : c == 'w' || c == 's' ? sizeof(ushort) :
-        c == 'i' ? sizeof(int) : c == 'f' ? sizeof(float) : c == 'd' ? sizeof(double) :
-        c == 'r' ? sizeof(void*) : (size_t)0);
-}
-
 FileStorage::FileStorage()
 {
     state = UNDEFINED;
@@ -164,8 +149,8 @@ void FileStorage::writeRaw( const String& fmt, const uchar* vec, size_t len )
 {
     if( !isOpened() )
         return;
-    size_t elemSize, cn;
-    getElemSize( fmt, elemSize, cn );
+    CV_Assert(!fmt.empty());
+    size_t elemSize = ::icvCalcStructSize(fmt.c_str(), 0);
     CV_Assert( len % elemSize == 0 );
     cvWriteRawData( fs, vec, (int)(len/elemSize), fmt.c_str());
 }
@@ -412,19 +397,30 @@ FileNodeIterator& FileNodeIterator::operator -= (int ofs)
 }
 
 
-FileNodeIterator& FileNodeIterator::readRaw( const String& fmt, uchar* vec, size_t maxCount )
+FileNodeIterator& FileNodeIterator::readRaw(const String& fmt, uchar* vec, size_t len)
 {
-    if( fs && container && remaining > 0 )
+    CV_Assert(!fmt.empty());
+    if( fs && container && remaining > 0 && len > 0)
     {
-        size_t elem_size, cn;
-        getElemSize( fmt, elem_size, cn );
-        CV_Assert( elem_size > 0 );
-        size_t count = std::min(remaining, maxCount);
-
-        if( reader.seq )
+        if (reader.seq)
         {
-            cvReadRawDataSlice( fs, (CvSeqReader*)&reader, (int)count, vec, fmt.c_str() );
-            remaining -= count*cn;
+            size_t step = ::icvCalcStructSize(fmt.c_str(), 0);
+            if (len % step && len != (size_t)INT_MAX)  // TODO remove compatibility hack
+            {
+                CV_PARSE_ERROR("readRaw: total byte size not match elememt size");
+            }
+            size_t maxCount = len / step;
+            int fmt_pairs[CV_FS_MAX_FMT_PAIRS*2] = {};
+            int fmt_pair_count = icvDecodeFormat(fmt.c_str(), fmt_pairs, CV_FS_MAX_FMT_PAIRS);
+            int vecElems = 0;
+            for (int k = 0; k < fmt_pair_count; k++)
+            {
+                vecElems += fmt_pairs[k*2];
+            }
+            CV_Assert(vecElems > 0);
+            size_t count = std::min((size_t)remaining, (size_t)maxCount * vecElems);
+            cvReadRawDataSlice(fs, (CvSeqReader*)&reader, (int)count, vec, fmt.c_str());
+            remaining -= count;
         }
         else
         {

modules/core/test/test_io.cpp

@@ -724,10 +724,10 @@ static void test_filestorage_basic(int write_flags, const char* suffix_name, boo
             fs << "empty_2d_mat"  << _em_out;
             fs << "random_mat"    << _rd_out;
 
-            cvStartWriteStruct( *fs, "rawdata", CV_NODE_SEQ | CV_NODE_FLOW, "binary" );
+            fs << "rawdata" << "[:";
             for (int i = 0; i < (int)rawdata_N/10; i++)
-                cvWriteRawData(*fs, rawdata.data() + i * 10, 10, data_t::signature());
-            cvEndWriteStruct( *fs );
+                fs.writeRaw(data_t::signature(), (const uchar*)&rawdata[i * 10], sizeof(data_t) * 10);
+            fs << "]";
 
             size_t sz = 0;
             if (useMemory)
@@ -763,7 +763,7 @@ static void test_filestorage_basic(int write_flags, const char* suffix_name, boo
 
             /* raw data */
             std::vector<data_t>(rawdata_N).swap(rawdata);
-            cvReadRawData(*fs, fs["rawdata"].node, rawdata.data(), data_t::signature());
+            fs["rawdata"].readRaw(data_t::signature(), (uchar*)&rawdata[0], rawdata.size() * sizeof(data_t));
 
             fs.release();
         }
@@ -925,7 +925,7 @@ TEST(Core_InputOutput, filestorage_base64_valid_call)
         {
             cv::FileStorage fs(file_name, cv::FileStorage::READ);
             std::vector<int> data_in(rawdata.size());
-            fs["manydata"][0].readRaw("i", (uchar *)data_in.data(), data_in.size());
+            fs["manydata"][0].readRaw("i", (uchar *)data_in.data(), data_in.size() * sizeof(data_in[0]));
             EXPECT_TRUE(fs["manydata"][0].isSeq());
             EXPECT_TRUE(std::equal(rawdata.begin(), rawdata.end(), data_in.begin()));
             cv::String str_in;
@@ -957,7 +957,7 @@ TEST(Core_InputOutput, filestorage_base64_valid_call)
             EXPECT_TRUE(fs["manydata"][0].isString());
             EXPECT_EQ(str_in, str_out);
             std::vector<int> data_in(rawdata.size());
-            fs["manydata"][1].readRaw("i", (uchar *)data_in.data(), data_in.size());
+            fs["manydata"][1].readRaw("i", (uchar *)data_in.data(), data_in.size() * sizeof(data_in[0]));
             EXPECT_TRUE(fs["manydata"][1].isSeq());
             EXPECT_TRUE(std::equal(rawdata.begin(), rawdata.end(), data_in.begin()));
             fs.release();