Function PNG_decode

Protocols/AppleImageCodec/picopng.c:1041–1279

}

PNG_INFO *PNG_decode(/* const*/ UINT8 *in, UINT32 size)
{
	UINT32 pos ;
	VECTOR_8 *idat;
	BOOLEAN IEND; //,known_type;
	UINT32 bpp;
	PNG_INFO *info;
	VECTOR_8 *scanlines; // now the out buffer will be filled
	UINT32 bytewidth, outlength ;
	UINT8 *out_data;
  
	PNG_error = 0;
  
	if (size == 0 || in == 0)
	{
		PNG_error = 48; // the given data is empty
		DBG("the given data is empty\n");
		return NULL;
	}
	info = PNG_info_new();
	PNG_readPngHeader(info, in, size);
	if (PNG_error){
		DBG("readPngHeader PNG_error=%d\n", PNG_error);
		return NULL;
	}
	pos = 33; // first byte of the first chunk after the header
	idat = NULL; // the data from idat chunks
	IEND = FALSE;
  //	known_type = TRUE;
	info->key_defined = FALSE;
	// loop through the chunks, ignoring unknown chunks and stopping at IEND chunk. IDAT data is
	// put at the start of the in buffer
	while (!IEND)
	{
		UINT32 i, j;
		UINT32 chunkLength ;
		UINT32 chunkType;
    UINT32 offset = 0;
		if (pos + 8 >= size)
		{
			PNG_error = 30; // error: size of the in buffer too small to contain next chunk
			DBG("error: size of the in buffer too small to contain next chunk size=%d\n", size);
			return NULL;
		}
		chunkLength = PNG_read32bitInt(&in[pos]); //big endian? Yes!
		pos += 4;
		if (chunkLength > 0x7fffffff)
		{
			PNG_error = 63;
			return NULL;
		}
		if (pos + chunkLength >= size) {
			PNG_error = 35; // error: size of the in buffer too small to contain next chunk
			return NULL;
		}
    //		chunkType = *(UINT32 *) &in[pos];
    chunkType = PNG_read32bitLE(&in[pos]); //read as LE to compare with our constants
    switch (chunkType) {