/* pngpread.c - read a png file in push mode | |
* | |
* Last changed in libpng 1.6.0 [February 14, 2013] | |
* Copyright (c) 1998-2013 Glenn Randers-Pehrson | |
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) | |
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) | |
* | |
* This code is released under the libpng license. | |
* For conditions of distribution and use, see the disclaimer | |
* and license in png.h | |
*/ | |
#include "pngpriv.h" | |
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED | |
/* Push model modes */ | |
#define PNG_READ_SIG_MODE 0 | |
#define PNG_READ_CHUNK_MODE 1 | |
#define PNG_READ_IDAT_MODE 2 | |
#define PNG_SKIP_MODE 3 | |
#define PNG_READ_tEXt_MODE 4 | |
#define PNG_READ_zTXt_MODE 5 | |
#define PNG_READ_DONE_MODE 6 | |
#define PNG_READ_iTXt_MODE 7 | |
#define PNG_ERROR_MODE 8 | |
void PNGAPI | |
png_process_data(png_structrp png_ptr, png_inforp info_ptr, | |
png_bytep buffer, png_size_t buffer_size) | |
{ | |
if (png_ptr == NULL || info_ptr == NULL) | |
return; | |
png_push_restore_buffer(png_ptr, buffer, buffer_size); | |
while (png_ptr->buffer_size) | |
{ | |
png_process_some_data(png_ptr, info_ptr); | |
} | |
} | |
png_size_t PNGAPI | |
png_process_data_pause(png_structrp png_ptr, int save) | |
{ | |
if (png_ptr != NULL) | |
{ | |
/* It's easiest for the caller if we do the save, then the caller doesn't | |
* have to supply the same data again: | |
*/ | |
if (save) | |
png_push_save_buffer(png_ptr); | |
else | |
{ | |
/* This includes any pending saved bytes: */ | |
png_size_t remaining = png_ptr->buffer_size; | |
png_ptr->buffer_size = 0; | |
/* So subtract the saved buffer size, unless all the data | |
* is actually 'saved', in which case we just return 0 | |
*/ | |
if (png_ptr->save_buffer_size < remaining) | |
return remaining - png_ptr->save_buffer_size; | |
} | |
} | |
return 0; | |
} | |
png_uint_32 PNGAPI | |
png_process_data_skip(png_structrp png_ptr) | |
{ | |
png_uint_32 remaining = 0; | |
if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE && | |
png_ptr->skip_length > 0) | |
{ | |
/* At the end of png_process_data the buffer size must be 0 (see the loop | |
* above) so we can detect a broken call here: | |
*/ | |
if (png_ptr->buffer_size != 0) | |
png_error(png_ptr, | |
"png_process_data_skip called inside png_process_data"); | |
/* If is impossible for there to be a saved buffer at this point - | |
* otherwise we could not be in SKIP mode. This will also happen if | |
* png_process_skip is called inside png_process_data (but only very | |
* rarely.) | |
*/ | |
if (png_ptr->save_buffer_size != 0) | |
png_error(png_ptr, "png_process_data_skip called with saved data"); | |
remaining = png_ptr->skip_length; | |
png_ptr->skip_length = 0; | |
png_ptr->process_mode = PNG_READ_CHUNK_MODE; | |
} | |
return remaining; | |
} | |
/* What we do with the incoming data depends on what we were previously | |
* doing before we ran out of data... | |
*/ | |
void /* PRIVATE */ | |
png_process_some_data(png_structrp png_ptr, png_inforp info_ptr) | |
{ | |
if (png_ptr == NULL) | |
return; | |
switch (png_ptr->process_mode) | |
{ | |
case PNG_READ_SIG_MODE: | |
{ | |
png_push_read_sig(png_ptr, info_ptr); | |
break; | |
} | |
case PNG_READ_CHUNK_MODE: | |
{ | |
png_push_read_chunk(png_ptr, info_ptr); | |
break; | |
} | |
case PNG_READ_IDAT_MODE: | |
{ | |
png_push_read_IDAT(png_ptr); | |
break; | |
} | |
case PNG_SKIP_MODE: | |
{ | |
png_push_crc_finish(png_ptr); | |
break; | |
} | |
default: | |
{ | |
png_ptr->buffer_size = 0; | |
break; | |
} | |
} | |
} | |
/* Read any remaining signature bytes from the stream and compare them with | |
* the correct PNG signature. It is possible that this routine is called | |
* with bytes already read from the signature, either because they have been | |
* checked by the calling application, or because of multiple calls to this | |
* routine. | |
*/ | |
void /* PRIVATE */ | |
png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr) | |
{ | |
png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */ | |
num_to_check = 8 - num_checked; | |
if (png_ptr->buffer_size < num_to_check) | |
{ | |
num_to_check = png_ptr->buffer_size; | |
} | |
png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), | |
num_to_check); | |
png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check); | |
if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) | |
{ | |
if (num_checked < 4 && | |
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) | |
png_error(png_ptr, "Not a PNG file"); | |
else | |
png_error(png_ptr, "PNG file corrupted by ASCII conversion"); | |
} | |
else | |
{ | |
if (png_ptr->sig_bytes >= 8) | |
{ | |
png_ptr->process_mode = PNG_READ_CHUNK_MODE; | |
} | |
} | |
} | |
void /* PRIVATE */ | |
png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) | |
{ | |
png_uint_32 chunk_name; | |
#ifdef PNG_HANDLE_AS_UNKNOWN_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; | |
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_HANDLE_AS_UNKNOWN_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) | |
{ | |
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 | |
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; | |
} | |
void /* PRIVATE */ | |
png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip) | |
{ | |
png_ptr->process_mode = PNG_SKIP_MODE; | |
png_ptr->skip_length = skip; | |
} | |
void /* PRIVATE */ | |
png_push_crc_finish(png_structrp png_ptr) | |
{ | |
if (png_ptr->skip_length && png_ptr->save_buffer_size) | |
{ | |
png_size_t save_size = png_ptr->save_buffer_size; | |
png_uint_32 skip_length = png_ptr->skip_length; | |
/* We want the smaller of 'skip_length' and 'save_buffer_size', but | |
* they are of different types and we don't know which variable has the | |
* fewest bits. Carefully select the smaller and cast it to the type of | |
* the larger - this cannot overflow. Do not cast in the following test | |
* - it will break on either 16 or 64 bit platforms. | |
*/ | |
if (skip_length < save_size) | |
save_size = (png_size_t)skip_length; | |
else | |
skip_length = (png_uint_32)save_size; | |
png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); | |
png_ptr->skip_length -= skip_length; | |
png_ptr->buffer_size -= save_size; | |
png_ptr->save_buffer_size -= save_size; | |
png_ptr->save_buffer_ptr += save_size; | |
} | |
if (png_ptr->skip_length && png_ptr->current_buffer_size) | |
{ | |
png_size_t save_size = png_ptr->current_buffer_size; | |
png_uint_32 skip_length = png_ptr->skip_length; | |
/* We want the smaller of 'skip_length' and 'current_buffer_size', here, | |
* the same problem exists as above and the same solution. | |
*/ | |
if (skip_length < save_size) | |
save_size = (png_size_t)skip_length; | |
else | |
skip_length = (png_uint_32)save_size; | |
png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); | |
png_ptr->skip_length -= skip_length; | |
png_ptr->buffer_size -= save_size; | |
png_ptr->current_buffer_size -= save_size; | |
png_ptr->current_buffer_ptr += save_size; | |
} | |
if (!png_ptr->skip_length) | |
{ | |
if (png_ptr->buffer_size < 4) | |
{ | |
png_push_save_buffer(png_ptr); | |
return; | |
} | |
png_crc_finish(png_ptr, 0); | |
png_ptr->process_mode = PNG_READ_CHUNK_MODE; | |
} | |
} | |
void PNGCBAPI | |
png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length) | |
{ | |
png_bytep ptr; | |
if (png_ptr == NULL) | |
return; | |
ptr = buffer; | |
if (png_ptr->save_buffer_size) | |
{ | |
png_size_t save_size; | |
if (length < png_ptr->save_buffer_size) | |
save_size = length; | |
else | |
save_size = png_ptr->save_buffer_size; | |
memcpy(ptr, png_ptr->save_buffer_ptr, save_size); | |
length -= save_size; | |
ptr += save_size; | |
png_ptr->buffer_size -= save_size; | |
png_ptr->save_buffer_size -= save_size; | |
png_ptr->save_buffer_ptr += save_size; | |
} | |
if (length && png_ptr->current_buffer_size) | |
{ | |
png_size_t save_size; | |
if (length < png_ptr->current_buffer_size) | |
save_size = length; | |
else | |
save_size = png_ptr->current_buffer_size; | |
memcpy(ptr, png_ptr->current_buffer_ptr, save_size); | |
png_ptr->buffer_size -= save_size; | |
png_ptr->current_buffer_size -= save_size; | |
png_ptr->current_buffer_ptr += save_size; | |
} | |
} | |
void /* PRIVATE */ | |
png_push_save_buffer(png_structrp png_ptr) | |
{ | |
if (png_ptr->save_buffer_size) | |
{ | |
if (png_ptr->save_buffer_ptr != png_ptr->save_buffer) | |
{ | |
png_size_t i, istop; | |
png_bytep sp; | |
png_bytep dp; | |
istop = png_ptr->save_buffer_size; | |
for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer; | |
i < istop; i++, sp++, dp++) | |
{ | |
*dp = *sp; | |
} | |
} | |
} | |
if (png_ptr->save_buffer_size + png_ptr->current_buffer_size > | |
png_ptr->save_buffer_max) | |
{ | |
png_size_t new_max; | |
png_bytep old_buffer; | |
if (png_ptr->save_buffer_size > PNG_SIZE_MAX - | |
(png_ptr->current_buffer_size + 256)) | |
{ | |
png_error(png_ptr, "Potential overflow of save_buffer"); | |
} | |
new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256; | |
old_buffer = png_ptr->save_buffer; | |
png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, | |
(png_size_t)new_max); | |
if (png_ptr->save_buffer == NULL) | |
{ | |
png_free(png_ptr, old_buffer); | |
png_error(png_ptr, "Insufficient memory for save_buffer"); | |
} | |
memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size); | |
png_free(png_ptr, old_buffer); | |
png_ptr->save_buffer_max = new_max; | |
} | |
if (png_ptr->current_buffer_size) | |
{ | |
memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size, | |
png_ptr->current_buffer_ptr, png_ptr->current_buffer_size); | |
png_ptr->save_buffer_size += png_ptr->current_buffer_size; | |
png_ptr->current_buffer_size = 0; | |
} | |
png_ptr->save_buffer_ptr = png_ptr->save_buffer; | |
png_ptr->buffer_size = 0; | |
} | |
void /* PRIVATE */ | |
png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer, | |
png_size_t buffer_length) | |
{ | |
png_ptr->current_buffer = buffer; | |
png_ptr->current_buffer_size = buffer_length; | |
png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size; | |
png_ptr->current_buffer_ptr = png_ptr->current_buffer; | |
} | |
void /* PRIVATE */ | |
png_push_read_IDAT(png_structrp png_ptr) | |
{ | |
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) | |
{ | |
png_byte chunk_length[4]; | |
png_byte chunk_tag[4]; | |
/* TODO: this code can be commoned up with the same code in push_read */ | |
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_ptr->mode |= PNG_HAVE_CHUNK_HEADER; | |
if (png_ptr->chunk_name != png_IDAT) | |
{ | |
png_ptr->process_mode = PNG_READ_CHUNK_MODE; | |
if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) | |
png_error(png_ptr, "Not enough compressed data"); | |
return; | |
} | |
png_ptr->idat_size = png_ptr->push_length; | |
} | |
if (png_ptr->idat_size && png_ptr->save_buffer_size) | |
{ | |
png_size_t save_size = png_ptr->save_buffer_size; | |
png_uint_32 idat_size = png_ptr->idat_size; | |
/* We want the smaller of 'idat_size' and 'current_buffer_size', but they | |
* are of different types and we don't know which variable has the fewest | |
* bits. Carefully select the smaller and cast it to the type of the | |
* larger - this cannot overflow. Do not cast in the following test - it | |
* will break on either 16 or 64 bit platforms. | |
*/ | |
if (idat_size < save_size) | |
save_size = (png_size_t)idat_size; | |
else | |
idat_size = (png_uint_32)save_size; | |
png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); | |
png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size); | |
png_ptr->idat_size -= idat_size; | |
png_ptr->buffer_size -= save_size; | |
png_ptr->save_buffer_size -= save_size; | |
png_ptr->save_buffer_ptr += save_size; | |
} | |
if (png_ptr->idat_size && png_ptr->current_buffer_size) | |
{ | |
png_size_t save_size = png_ptr->current_buffer_size; | |
png_uint_32 idat_size = png_ptr->idat_size; | |
/* We want the smaller of 'idat_size' and 'current_buffer_size', but they | |
* are of different types and we don't know which variable has the fewest | |
* bits. Carefully select the smaller and cast it to the type of the | |
* larger - this cannot overflow. | |
*/ | |
if (idat_size < save_size) | |
save_size = (png_size_t)idat_size; | |
else | |
idat_size = (png_uint_32)save_size; | |
png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); | |
png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size); | |
png_ptr->idat_size -= idat_size; | |
png_ptr->buffer_size -= save_size; | |
png_ptr->current_buffer_size -= save_size; | |
png_ptr->current_buffer_ptr += save_size; | |
} | |
if (!png_ptr->idat_size) | |
{ | |
if (png_ptr->buffer_size < 4) | |
{ | |
png_push_save_buffer(png_ptr); | |
return; | |
} | |
png_crc_finish(png_ptr, 0); | |
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; | |
png_ptr->mode |= PNG_AFTER_IDAT; | |
png_ptr->zowner = 0; | |
} | |
} | |
void /* PRIVATE */ | |
png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer, | |
png_size_t buffer_length) | |
{ | |
/* The caller checks for a non-zero buffer length. */ | |
if (!(buffer_length > 0) || buffer == NULL) | |
png_error(png_ptr, "No IDAT data (internal error)"); | |
/* This routine must process all the data it has been given | |
* before returning, calling the row callback as required to | |
* handle the uncompressed results. | |
*/ | |
png_ptr->zstream.next_in = buffer; | |
/* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */ | |
png_ptr->zstream.avail_in = (uInt)buffer_length; | |
/* Keep going until the decompressed data is all processed | |
* or the stream marked as finished. | |
*/ | |
while (png_ptr->zstream.avail_in > 0 && | |
!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) | |
{ | |
int ret; | |
/* We have data for zlib, but we must check that zlib | |
* has someplace to put the results. It doesn't matter | |
* if we don't expect any results -- it may be the input | |
* data is just the LZ end code. | |
*/ | |
if (!(png_ptr->zstream.avail_out > 0)) | |
{ | |
/* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */ | |
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; | |
} | |
/* Using Z_SYNC_FLUSH here means that an unterminated | |
* LZ stream (a stream with a missing end code) can still | |
* be handled, otherwise (Z_NO_FLUSH) a future zlib | |
* implementation might defer output and therefore | |
* change the current behavior (see comments in inflate.c | |
* for why this doesn't happen at present with zlib 1.2.5). | |
*/ | |
ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH); | |
/* Check for any failure before proceeding. */ | |
if (ret != Z_OK && ret != Z_STREAM_END) | |
{ | |
/* Terminate the decompression. */ | |
png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; | |
png_ptr->zowner = 0; | |
/* This may be a truncated stream (missing or | |
* damaged end code). Treat that as a warning. | |
*/ | |
if (png_ptr->row_number >= png_ptr->num_rows || | |
png_ptr->pass > 6) | |
png_warning(png_ptr, "Truncated compressed data in IDAT"); | |
else | |
png_error(png_ptr, "Decompression error in IDAT"); | |
/* Skip the check on unprocessed input */ | |
return; | |
} | |
/* Did inflate output any data? */ | |
if (png_ptr->zstream.next_out != png_ptr->row_buf) | |
{ | |
/* Is this unexpected data after the last row? | |
* If it is, artificially terminate the LZ output | |
* here. | |
*/ | |
if (png_ptr->row_number >= png_ptr->num_rows || | |
png_ptr->pass > 6) | |
{ | |
/* Extra data. */ | |
png_warning(png_ptr, "Extra compressed data in IDAT"); | |
png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; | |
png_ptr->zowner = 0; | |
/* Do no more processing; skip the unprocessed | |
* input check below. | |
*/ | |
return; | |
} | |
/* Do we have a complete row? */ | |
if (png_ptr->zstream.avail_out == 0) | |
png_push_process_row(png_ptr); | |
} | |
/* And check for the end of the stream. */ | |
if (ret == Z_STREAM_END) | |
png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; | |
} | |
/* All the data should have been processed, if anything | |
* is left at this point we have bytes of IDAT data | |
* after the zlib end code. | |
*/ | |
if (png_ptr->zstream.avail_in > 0) | |
png_warning(png_ptr, "Extra compression data in IDAT"); | |
} | |
void /* PRIVATE */ | |
png_push_process_row(png_structrp png_ptr) | |
{ | |
/* 1.5.6: row_info moved out of png_struct to a local here. */ | |
png_row_info row_info; | |
row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */ | |
row_info.color_type = png_ptr->color_type; | |
row_info.bit_depth = png_ptr->bit_depth; | |
row_info.channels = png_ptr->channels; | |
row_info.pixel_depth = png_ptr->pixel_depth; | |
row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); | |
if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE) | |
{ | |
if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST) | |
png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1, | |
png_ptr->prev_row + 1, png_ptr->row_buf[0]); | |
else | |
png_error(png_ptr, "bad adaptive filter value"); | |
} | |
/* libpng 1.5.6: the following line was copying png_ptr->rowbytes before | |
* 1.5.6, while the buffer really is this big in current versions of libpng | |
* it may not be in the future, so this was changed just to copy the | |
* interlaced row count: | |
*/ | |
memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1); | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
if (png_ptr->transformations) | |
png_do_read_transformations(png_ptr, &row_info); | |
#endif | |
/* The transformed pixel depth should match the depth now in row_info. */ | |
if (png_ptr->transformed_pixel_depth == 0) | |
{ | |
png_ptr->transformed_pixel_depth = row_info.pixel_depth; | |
if (row_info.pixel_depth > png_ptr->maximum_pixel_depth) | |
png_error(png_ptr, "progressive row overflow"); | |
} | |
else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth) | |
png_error(png_ptr, "internal progressive row size calculation error"); | |
#ifdef PNG_READ_INTERLACING_SUPPORTED | |
/* Blow up interlaced rows to full size */ | |
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) | |
{ | |
if (png_ptr->pass < 6) | |
png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass, | |
png_ptr->transformations); | |
switch (png_ptr->pass) | |
{ | |
case 0: | |
{ | |
int i; | |
for (i = 0; i < 8 && png_ptr->pass == 0; i++) | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */ | |
} | |
if (png_ptr->pass == 2) /* Pass 1 might be empty */ | |
{ | |
for (i = 0; i < 4 && png_ptr->pass == 2; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
if (png_ptr->pass == 4 && png_ptr->height <= 4) | |
{ | |
for (i = 0; i < 2 && png_ptr->pass == 4; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
if (png_ptr->pass == 6 && png_ptr->height <= 4) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
break; | |
} | |
case 1: | |
{ | |
int i; | |
for (i = 0; i < 8 && png_ptr->pass == 1; i++) | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
} | |
if (png_ptr->pass == 2) /* Skip top 4 generated rows */ | |
{ | |
for (i = 0; i < 4 && png_ptr->pass == 2; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
break; | |
} | |
case 2: | |
{ | |
int i; | |
for (i = 0; i < 4 && png_ptr->pass == 2; i++) | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
} | |
for (i = 0; i < 4 && png_ptr->pass == 2; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
if (png_ptr->pass == 4) /* Pass 3 might be empty */ | |
{ | |
for (i = 0; i < 2 && png_ptr->pass == 4; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
break; | |
} | |
case 3: | |
{ | |
int i; | |
for (i = 0; i < 4 && png_ptr->pass == 3; i++) | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
} | |
if (png_ptr->pass == 4) /* Skip top two generated rows */ | |
{ | |
for (i = 0; i < 2 && png_ptr->pass == 4; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
break; | |
} | |
case 4: | |
{ | |
int i; | |
for (i = 0; i < 2 && png_ptr->pass == 4; i++) | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
} | |
for (i = 0; i < 2 && png_ptr->pass == 4; i++) | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
if (png_ptr->pass == 6) /* Pass 5 might be empty */ | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
break; | |
} | |
case 5: | |
{ | |
int i; | |
for (i = 0; i < 2 && png_ptr->pass == 5; i++) | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
} | |
if (png_ptr->pass == 6) /* Skip top generated row */ | |
{ | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
break; | |
} | |
default: | |
case 6: | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
if (png_ptr->pass != 6) | |
break; | |
png_push_have_row(png_ptr, NULL); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
} | |
else | |
#endif | |
{ | |
png_push_have_row(png_ptr, png_ptr->row_buf + 1); | |
png_read_push_finish_row(png_ptr); | |
} | |
} | |
void /* PRIVATE */ | |
png_read_push_finish_row(png_structrp png_ptr) | |
{ | |
#ifdef PNG_READ_INTERLACING_SUPPORTED | |
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ | |
/* Start of interlace block */ | |
static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; | |
/* Offset to next interlace block */ | |
static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; | |
/* Start of interlace block in the y direction */ | |
static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; | |
/* Offset to next interlace block in the y direction */ | |
static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; | |
/* Height of interlace block. This is not currently used - if you need | |
* it, uncomment it here and in png.h | |
static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; | |
*/ | |
#endif | |
png_ptr->row_number++; | |
if (png_ptr->row_number < png_ptr->num_rows) | |
return; | |
#ifdef PNG_READ_INTERLACING_SUPPORTED | |
if (png_ptr->interlaced) | |
{ | |
png_ptr->row_number = 0; | |
memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); | |
do | |
{ | |
png_ptr->pass++; | |
if ((png_ptr->pass == 1 && png_ptr->width < 5) || | |
(png_ptr->pass == 3 && png_ptr->width < 3) || | |
(png_ptr->pass == 5 && png_ptr->width < 2)) | |
png_ptr->pass++; | |
if (png_ptr->pass > 7) | |
png_ptr->pass--; | |
if (png_ptr->pass >= 7) | |
break; | |
png_ptr->iwidth = (png_ptr->width + | |
png_pass_inc[png_ptr->pass] - 1 - | |
png_pass_start[png_ptr->pass]) / | |
png_pass_inc[png_ptr->pass]; | |
if (png_ptr->transformations & PNG_INTERLACE) | |
break; | |
png_ptr->num_rows = (png_ptr->height + | |
png_pass_yinc[png_ptr->pass] - 1 - | |
png_pass_ystart[png_ptr->pass]) / | |
png_pass_yinc[png_ptr->pass]; | |
} while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0); | |
} | |
#endif /* PNG_READ_INTERLACING_SUPPORTED */ | |
} | |
void /* PRIVATE */ | |
png_push_have_info(png_structrp png_ptr, png_inforp info_ptr) | |
{ | |
if (png_ptr->info_fn != NULL) | |
(*(png_ptr->info_fn))(png_ptr, info_ptr); | |
} | |
void /* PRIVATE */ | |
png_push_have_end(png_structrp png_ptr, png_inforp info_ptr) | |
{ | |
if (png_ptr->end_fn != NULL) | |
(*(png_ptr->end_fn))(png_ptr, info_ptr); | |
} | |
void /* PRIVATE */ | |
png_push_have_row(png_structrp png_ptr, png_bytep row) | |
{ | |
if (png_ptr->row_fn != NULL) | |
(*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number, | |
(int)png_ptr->pass); | |
} | |
#ifdef PNG_READ_INTERLACING_SUPPORTED | |
void PNGAPI | |
png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row, | |
png_const_bytep new_row) | |
{ | |
if (png_ptr == NULL) | |
return; | |
/* new_row is a flag here - if it is NULL then the app callback was called | |
* from an empty row (see the calls to png_struct::row_fn below), otherwise | |
* it must be png_ptr->row_buf+1 | |
*/ | |
if (new_row != NULL) | |
png_combine_row(png_ptr, old_row, 1/*display*/); | |
} | |
#endif /* PNG_READ_INTERLACING_SUPPORTED */ | |
void PNGAPI | |
png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr, | |
png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, | |
png_progressive_end_ptr end_fn) | |
{ | |
if (png_ptr == NULL) | |
return; | |
png_ptr->info_fn = info_fn; | |
png_ptr->row_fn = row_fn; | |
png_ptr->end_fn = end_fn; | |
png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer); | |
} | |
png_voidp PNGAPI | |
png_get_progressive_ptr(png_const_structrp png_ptr) | |
{ | |
if (png_ptr == NULL) | |
return (NULL); | |
return png_ptr->io_ptr; | |
} | |
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ |