diff options
Diffstat (limited to 'media/libpng/pngpread.c')
| -rw-r--r-- | media/libpng/pngpread.c | 1265 |
1 files changed, 1265 insertions, 0 deletions
diff --git a/media/libpng/pngpread.c b/media/libpng/pngpread.c new file mode 100644 index 0000000000..7d452a76f2 --- /dev/null +++ b/media/libpng/pngpread.c @@ -0,0 +1,1265 @@ + +/* pngpread.c - read a png file in push mode + * + * Copyright (c) 2018 Cosmin Truta + * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson + * Copyright (c) 1996-1997 Andreas Dilger + * 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_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 + +#define PNG_PUSH_SAVE_BUFFER_IF_FULL \ +if (png_ptr->push_length + 4 > png_ptr->buffer_size) \ + { png_push_save_buffer(png_ptr); return; } +#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \ +if (png_ptr->buffer_size < N) \ + { png_push_save_buffer(png_ptr); return; } + +void PNGAPI +png_process_data(png_structrp png_ptr, png_inforp info_ptr, + png_bytep buffer, 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); + } +} + +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 != 0) + png_push_save_buffer(png_ptr); + else + { + /* This includes any pending saved bytes: */ + 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) +{ +/* TODO: Deprecate and remove this API. + * Somewhere the implementation of this seems to have been lost, + * or abandoned. It was only to support some internal back-door access + * to png_struct) in libpng-1.4.x. + */ + png_app_warning(png_ptr, +"png_process_data_skip is not implemented in any current version of libpng"); + return 0; +} + +/* 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; + } + + 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) +{ + size_t num_checked = png_ptr->sig_bytes; /* SAFE, does not exceed 8 */ + size_t 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) == 0) + { + png_byte chunk_length[4]; + png_byte chunk_tag[4]; + + PNG_PUSH_SAVE_BUFFER_IF_LT(8) + 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_check_chunk_length(png_ptr, png_ptr->push_length); + 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) != 0 || + png_ptr->num_frames_read > 1) + png_error(png_ptr, "out of place IDAT"); + + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_crc_finish(png_ptr, png_ptr->push_length); + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; + } + + else if (chunk_name == png_fdAT) + { + PNG_PUSH_SAVE_BUFFER_IF_LT(4) + png_ensure_sequence_number(png_ptr, 4); + + if ((png_ptr->mode & PNG_HAVE_fcTL) == 0) + { + /* Discard trailing fdATs for frames other than the first */ + if (png_ptr->num_frames_read < 2) + png_error(png_ptr, "out of place fdAT"); + + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_crc_finish(png_ptr, png_ptr->push_length); + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; + } + + 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; + } + } + + else if (chunk_name == png_fcTL) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) == 0) + 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; + } + + else if (chunk_name == png_IEND) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_warning(png_ptr, "Number of actual frames fewer than expected"); + png_crc_finish(png_ptr, png_ptr->push_length); + png_ptr->process_mode = PNG_READ_DONE_MODE; + png_push_have_end(png_ptr, info_ptr); + } + + else + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_warning(png_ptr, "Skipped (ignored) a chunk " + "between APNG chunks"); + png_crc_finish(png_ptr, png_ptr->push_length); + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; + } + + return; + } +#endif /* READ_APNG */ + + if (chunk_name == png_IDAT) + { + if ((png_ptr->mode & PNG_AFTER_IDAT) != 0) + 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) == 0) + png_error(png_ptr, "Missing IHDR before IDAT"); + + else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && + (png_ptr->mode & PNG_HAVE_PLTE) == 0) + png_error(png_ptr, "Missing PLTE before IDAT"); + + png_ptr->process_mode = PNG_READ_IDAT_MODE; + + if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) + if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0) + if (png_ptr->push_length == 0) + return; + + png_ptr->mode |= PNG_HAVE_IDAT; + + if ((png_ptr->mode & PNG_AFTER_IDAT) != 0) + 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"); + + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length); + } + + else if (chunk_name == png_IEND) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sRGB_SUPPORTED + else if (chunk_name == png_sRGB) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + 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) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sPLT_SUPPORTED + else if (chunk_name == png_sPLT) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_tRNS_SUPPORTED + else if (chunk_name == png_tRNS) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_bKGD_SUPPORTED + else if (chunk_name == png_bKGD) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_hIST_SUPPORTED + else if (chunk_name == png_hIST) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_pHYs_SUPPORTED + else if (chunk_name == png_pHYs) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_oFFs_SUPPORTED + else if (chunk_name == png_oFFs) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length); + } +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED + else if (chunk_name == png_pCAL) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sCAL_SUPPORTED + else if (chunk_name == png_sCAL) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_tIME_SUPPORTED + else if (chunk_name == png_tIME) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_tEXt_SUPPORTED + else if (chunk_name == png_tEXt) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_zTXt_SUPPORTED + else if (chunk_name == png_zTXt) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_iTXt_SUPPORTED + else if (chunk_name == png_iTXt) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length); + } +#endif + +#ifdef PNG_READ_APNG_SUPPORTED + else if (chunk_name == png_acTL) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_acTL(png_ptr, info_ptr, png_ptr->push_length); + } + + else if (chunk_name == png_fcTL) + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif /* READ_APNG */ + else + { + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, + PNG_HANDLE_CHUNK_AS_DEFAULT); + } + + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; +} + +void PNGCBAPI +png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, size_t length) +{ + png_bytep ptr; + + if (png_ptr == NULL) + return; + + ptr = buffer; + if (png_ptr->save_buffer_size != 0) + { + 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 != 0 && png_ptr->current_buffer_size != 0) + { + 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 != 0) + { + if (png_ptr->save_buffer_ptr != png_ptr->save_buffer) + { + 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) + { + 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, + (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"); + } + + if (old_buffer) + memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size); + else if (png_ptr->save_buffer_size) + png_error(png_ptr, "save_buffer error"); + 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, + 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) == 0) + { + png_byte chunk_length[4]; + png_byte chunk_tag[4]; + + /* TODO: this code can be commoned up with the same code in push_read */ +#ifdef PNG_READ_APNG_SUPPORTED + PNG_PUSH_SAVE_BUFFER_IF_LT(12) +#else + PNG_PUSH_SAVE_BUFFER_IF_LT(8) +#endif + 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; + +#ifdef PNG_READ_APNG_SUPPORTED + if (png_ptr->chunk_name != png_fdAT && png_ptr->num_frames_read > 0) + { + if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) != 0) + { + png_ptr->process_mode = PNG_READ_CHUNK_MODE; + if (png_ptr->frame_end_fn != NULL) + (*(png_ptr->frame_end_fn))(png_ptr, png_ptr->num_frames_read); + png_ptr->num_frames_read++; + return; + } + else + { + if (png_ptr->chunk_name == png_IEND) + png_error(png_ptr, "Not enough image data"); + PNG_PUSH_SAVE_BUFFER_IF_FULL + png_warning(png_ptr, "Skipping (ignoring) a chunk between " + "APNG chunks"); + png_crc_finish(png_ptr, png_ptr->push_length); + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; + return; + } + } + else +#endif +#ifdef PNG_READ_APNG_SUPPORTED + if (png_ptr->chunk_name != png_IDAT && png_ptr->num_frames_read == 0) +#else + if (png_ptr->chunk_name != png_IDAT) +#endif + { + png_ptr->process_mode = PNG_READ_CHUNK_MODE; + + if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0) + png_error(png_ptr, "Not enough compressed data"); + +#ifdef PNG_READ_APNG_SUPPORTED + if (png_ptr->frame_end_fn != NULL) + (*(png_ptr->frame_end_fn))(png_ptr, png_ptr->num_frames_read); + png_ptr->num_frames_read++; +#endif + + return; + } + + png_ptr->idat_size = png_ptr->push_length; + +#ifdef PNG_READ_APNG_SUPPORTED + if (png_ptr->num_frames_read > 0) + { + png_ensure_sequence_number(png_ptr, 4); + png_ptr->idat_size -= 4; + } +#endif + } + + if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0) + { + 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-bit or 64-bit platforms. + */ + if (idat_size < save_size) + save_size = (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 != 0 && png_ptr->current_buffer_size != 0) + { + 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 = (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 == 0) + { + PNG_PUSH_SAVE_BUFFER_IF_LT(4) + 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, + 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)"); + +#ifdef PNG_READ_APNG_SUPPORTED + /* If the app is not APNG-aware, decode only the first frame */ + if ((png_ptr->apng_flags & PNG_APNG_APP) == 0 && + png_ptr->num_frames_read > 0) + { + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + return; + } +#endif + + /* 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) == 0) + { + 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 = PNG_INFLATE(png_ptr, 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 + { + if (ret == Z_DATA_ERROR) + png_benign_error(png_ptr, "IDAT: ADLER32 checksum mismatch"); + 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 != 0) + 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 + /* Expand interlaced rows to full size */ + if (png_ptr->interlaced != 0 && + (png_ptr->transformations & PNG_INTERLACE) != 0) + { + 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 const png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static const png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static const png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static 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 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 != 0) + { + 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) != 0) + 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 /* READ_INTERLACING */ +} + +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/*blocky display*/); +} +#endif /* READ_INTERLACING */ + +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); +} + +#ifdef PNG_READ_APNG_SUPPORTED +void PNGAPI +png_set_progressive_frame_fn(png_structp png_ptr, + png_progressive_frame_ptr frame_info_fn, + png_progressive_frame_ptr frame_end_fn) +{ + png_ptr->frame_info_fn = frame_info_fn; + png_ptr->frame_end_fn = frame_end_fn; + png_ptr->apng_flags |= PNG_APNG_APP; +} +#endif + +png_voidp PNGAPI +png_get_progressive_ptr(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return (NULL); + + return png_ptr->io_ptr; +} +#endif /* PROGRESSIVE_READ */ |