void PngChunk::decode(Image* pImage,
const byte* pData,
long size)
{
assert(pImage != 0);
assert(pData != 0);
// look for a tEXt chunk
long index = 8;
index += getLong(&pData[index], bigEndian) + PNG_CHUNK_HEADER_SIZE;
while(index < size-PNG_CHUNK_HEADER_SIZE)
{
while (index < size-PNG_CHUNK_HEADER_SIZE &&
strncmp((char*)PNG_CHUNK_TYPE(pData, index), "tEXt", 4) &&
strncmp((char*)PNG_CHUNK_TYPE(pData, index), "zTXt", 4) &&
strncmp((char*)PNG_CHUNK_TYPE(pData, index), "iTXt", 4))
{
if (!strncmp((char*)PNG_CHUNK_TYPE(pData, index), "IEND", 4))
throw Error(14);
index += getLong(&pData[index], bigEndian) + PNG_CHUNK_HEADER_SIZE;
}
if (index < size-PNG_CHUNK_HEADER_SIZE)
{
// we found a tEXt, zTXt, or iTXt field
// get the key, it's a null terminated string at the chunk start
const byte *key = &PNG_CHUNK_DATA(pData, index, 0);
int keysize=0;
for ( ; key[keysize] != 0 ; keysize++)
{
// look if we reached the end of the file (it might be corrupted)
if (8+index+keysize >= size)
throw Error(14);
}
DataBuf arr = parsePngChunk(pData, size, index, keysize);
#ifdef DEBUG
std::cerr << "Exiv2::PngChunk::decode: Found PNG chunk: "
<< std::string((const char*)key) << " :: "
<< std::string((const char*)arr.pData_, 32) << "\n";
#endif
parseChunkContent(pImage, key, arr);
index += getLong(&pData[index], bigEndian) + PNG_CHUNK_HEADER_SIZE;
}
}
} // PngChunk::decode
void PngChunk::decode(Image* pImage,
const byte* pData,
long size,
int* outWidth,
int* outHeight)
{
assert(pImage != 0);
assert(pData != 0);
assert(outWidth != 0);
assert(outHeight != 0);
long index = 8;
// extract width and height from IHDR chunk, which *must* be the first chunk in the PNG file
if (strncmp((const char *)PNG_CHUNK_TYPE(pData, index), "IHDR", 4) == 0)
{
*outWidth = getLong((const byte*)&PNG_CHUNK_DATA(pData, index, 0), bigEndian);
*outHeight = getLong((const byte*)&PNG_CHUNK_DATA(pData, index, 4), bigEndian);
}
// look for a tEXt chunk
index += chunkLength(pData, index) + PNG_CHUNK_HEADER_SIZE;
while(index < size-PNG_CHUNK_HEADER_SIZE)
{
while (index < size-PNG_CHUNK_HEADER_SIZE &&
strncmp((char*)PNG_CHUNK_TYPE(pData, index), "tEXt", 4) &&
strncmp((char*)PNG_CHUNK_TYPE(pData, index), "zTXt", 4) &&
strncmp((char*)PNG_CHUNK_TYPE(pData, index), "iTXt", 4))
{
if (!strncmp((char*)PNG_CHUNK_TYPE(pData, index), "IEND", 4))
throw Error(14);
index += chunkLength(pData, index) + PNG_CHUNK_HEADER_SIZE;
}
if (index < size-PNG_CHUNK_HEADER_SIZE)
{
// we found a tEXt, zTXt, or iTXt field
// get the key, it's a null terminated string at the chunk start
const byte *key = &PNG_CHUNK_DATA(pData, index, 0);
int keysize=0;
for ( ; key[keysize] != 0 ; keysize++)
{
// look if we reached the end of the file (it might be corrupted)
if (8+index+keysize >= size)
throw Error(14);
}
DataBuf arr = parsePngChunk(pData, size, index, keysize);
#ifdef DEBUG
std::cerr << "Exiv2::PngChunk::decode: Found PNG chunk: "
<< std::string((const char*)key) << " :: "
<< std::string((const char*)arr.pData_, 32) << "\n";
#endif
parseChunkContent(pImage, key, arr);
index += chunkLength(pData, index) + PNG_CHUNK_HEADER_SIZE;
}
}
} // PngChunk::decode
