void /* PRIVATE */
png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
length)
{
if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
{
png_error(png_ptr, "Out of place zTXt");
(void) info_ptr; /* to quiet some compiler warnings */
}
#ifdef PNG_MAX_MALLOC_64K
/* We can't handle zTXt chunks > 64K, since we don't have enough space
* to be able to store the uncompressed data. Actually, the threshold
* is probably around 32K, but it isn't as definite as 64K is.
*/
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "zTXt chunk too large to fit in memory");
png_push_crc_skip(png_ptr, length);
return;
}
#endif
png_ptr->current_text = (png_charp)png_malloc(png_ptr,
(png_uint_32)(length+1));
png_ptr->current_text[length] = '\0';
png_ptr->current_text_ptr = png_ptr->current_text;
png_ptr->current_text_size = (png_size_t)length;
png_ptr->current_text_left = (png_size_t)length;
png_ptr->process_mode = PNG_READ_zTXt_MODE;
}
/* This function is called when we haven't found a handler for this
* chunk. If there isn't a problem with the chunk itself (ie a bad chunk
* name or a critical chunk), the chunk is (currently) silently ignored.
*/
void /* PRIVATE */
png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
length)
{
png_uint_32 skip=0;
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
if (!(png_ptr->chunk_name[0] & 0x20))
{
#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS
#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
&& png_ptr->read_user_chunk_fn == NULL
#endif
)
#endif
png_chunk_error(png_ptr, "unknown critical chunk");
(void) info_ptr; /* to quiet some compiler warnings */
}
#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
{
#ifdef PNG_MAX_MALLOC_64K
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "unknown chunk too large to fit in memory");
skip = length - (png_uint_32)65535L;
length = (png_uint_32)65535L;
}
#endif
png_strncpy((png_charp)png_ptr->unknown_chunk.name,
(png_charp)png_ptr->chunk_name, 5);
png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
png_ptr->unknown_chunk.size = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
if(png_ptr->read_user_chunk_fn != NULL)
{
/* callback to user unknown chunk handler */
int ret;
ret = (*(png_ptr->read_user_chunk_fn))
(png_ptr, &png_ptr->unknown_chunk);
if (ret < 0)
png_chunk_error(png_ptr, "error in user chunk");
if (ret == 0)
{
if (!(png_ptr->chunk_name[0] & 0x20))
if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS)
png_chunk_error(png_ptr, "unknown critical chunk");
png_set_unknown_chunks(png_ptr, info_ptr,
&png_ptr->unknown_chunk, 1);
}
}
#else
png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
#endif
png_free(png_ptr, png_ptr->unknown_chunk.data);
png_ptr->unknown_chunk.data = NULL;
}
else
#endif
skip=length;
png_push_crc_skip(png_ptr, skip);
}
void /* PRIVATE */
png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
{
png_uint_32 chunk_name;
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
int keep; /* unknown handling method */
#endif
/* First we make sure we have enough data for the 4 byte chunk name
* and the 4 byte chunk length before proceeding with decoding the
* chunk data. To fully decode each of these chunks, we also make
* sure we have enough data in the buffer for the 4 byte CRC at the
* end of every chunk (except IDAT, which is handled separately).
*/
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
{
png_byte chunk_length[4];
png_byte chunk_tag[4];
if (png_ptr->buffer_size < 8)
{
png_push_save_buffer(png_ptr);
return;
}
png_push_fill_buffer(png_ptr, chunk_length, 4);
png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
png_reset_crc(png_ptr);
png_crc_read(png_ptr, chunk_tag, 4);
png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
}
chunk_name = png_ptr->chunk_name;
#ifdef PNG_READ_APNG_SUPPORTED
if (png_ptr->num_frames_read > 0 &&
png_ptr->num_frames_read < info_ptr->num_frames)
{
if (chunk_name == png_IDAT)
{
/* Discard trailing IDATs for the first frame */
if (png_ptr->mode & PNG_HAVE_fcTL || png_ptr->num_frames_read > 1)
png_error(png_ptr, "out of place IDAT");
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_push_crc_skip(png_ptr, png_ptr->push_length);
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
return;
}
else if (chunk_name == png_fdAT)
{
if (png_ptr->buffer_size < 4)
{
png_push_save_buffer(png_ptr);
return;
}
png_ensure_sequence_number(png_ptr, 4);
if (!(png_ptr->mode & PNG_HAVE_fcTL))
{
/* Discard trailing fdATs for frames other than the first */
if (png_ptr->num_frames_read < 2)
png_error(png_ptr, "out of place fdAT");
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_push_crc_skip(png_ptr, png_ptr->push_length);
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
return;
}
else
{
/* frame data follows */
png_ptr->idat_size = png_ptr->push_length - 4;
png_ptr->mode |= PNG_HAVE_IDAT;
png_ptr->process_mode = PNG_READ_IDAT_MODE;
return;
}
}
else if (chunk_name == png_fcTL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_read_reset(png_ptr);
png_ptr->mode &= ~PNG_HAVE_fcTL;
png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
if (!(png_ptr->mode & PNG_HAVE_fcTL))
png_error(png_ptr, "missing required fcTL chunk");
png_read_reinit(png_ptr, info_ptr);
png_progressive_read_reset(png_ptr);
if (png_ptr->frame_info_fn != NULL)
(*(png_ptr->frame_info_fn))(png_ptr, png_ptr->num_frames_read);
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
return;
}
else
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_warning(png_ptr, "Skipped (ignored) a chunk "
"between APNG chunks");
png_push_crc_skip(png_ptr, png_ptr->push_length);
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
return;
}
return;
}
#endif /* PNG_READ_APNG_SUPPORTED */
if (chunk_name == png_IDAT)
{
if (png_ptr->mode & PNG_AFTER_IDAT)
png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
/* If we reach an IDAT chunk, this means we have read all of the
* header chunks, and we can start reading the image (or if this
* is called after the image has been read - we have an error).
*/
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
!(png_ptr->mode & PNG_HAVE_PLTE))
png_error(png_ptr, "Missing PLTE before IDAT");
png_ptr->mode |= PNG_HAVE_IDAT;
if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
if (png_ptr->push_length == 0)
return;
if (png_ptr->mode & PNG_AFTER_IDAT)
png_benign_error(png_ptr, "Too many IDATs found");
}
if (chunk_name == png_IHDR)
{
if (png_ptr->push_length != 13)
png_error(png_ptr, "Invalid IHDR length");
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
}
else if (chunk_name == png_IEND)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
png_ptr->process_mode = PNG_READ_DONE_MODE;
png_push_have_end(png_ptr, info_ptr);
}
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
if (chunk_name == png_PLTE)
png_ptr->mode |= PNG_HAVE_PLTE;
}
#endif
else if (chunk_name == png_PLTE)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
}
else if (chunk_name == png_IDAT)
{
#ifdef PNG_READ_APNG_SUPPORTED
png_have_info(png_ptr, info_ptr);
#endif
png_ptr->idat_size = png_ptr->push_length;
png_ptr->process_mode = PNG_READ_IDAT_MODE;
png_push_have_info(png_ptr, info_ptr);
png_ptr->zstream.avail_out =
(uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
png_ptr->iwidth) + 1;
png_ptr->zstream.next_out = png_ptr->row_buf;
return;
}
#ifdef PNG_READ_gAMA_SUPPORTED
else if (png_ptr->chunk_name == png_gAMA)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
else if (png_ptr->chunk_name == png_sBIT)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
else if (png_ptr->chunk_name == png_cHRM)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
else if (chunk_name == png_sRGB)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
else if (png_ptr->chunk_name == png_iCCP)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
else if (chunk_name == png_sPLT)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
else if (chunk_name == png_tRNS)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_bKGD_SUPPORTED
else if (chunk_name == png_bKGD)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_hIST_SUPPORTED
else if (chunk_name == png_hIST)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
else if (chunk_name == png_pHYs)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
else if (chunk_name == png_oFFs)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
else if (chunk_name == png_pCAL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
else if (chunk_name == png_sCAL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_tIME_SUPPORTED
else if (chunk_name == png_tIME)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
else if (chunk_name == png_tEXt)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
else if (chunk_name == png_zTXt)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
else if (chunk_name == png_iTXt)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#ifdef PNG_READ_APNG_SUPPORTED
else if (chunk_name == png_acTL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_acTL(png_ptr, info_ptr, png_ptr->push_length);
}
else if (chunk_name == png_fcTL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
}
#endif /* PNG_READ_APNG_SUPPORTED */
else
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
PNG_HANDLE_CHUNK_AS_DEFAULT);
}
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
}