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https://github.com/FFmpeg/FFmpeg.git
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b3189aff8b
Since pc.state is populated by shifting in from the end of the
32 bit word, the content within pc.state is already in native endian
and should not be read with the AV_R{L,B} functions.
This was already done correctly for state64 above.
This fixes the fate-corepng test on big endian.
Signed-off-by: Martin Storsjö <martin@martin.st>
125 lines
3.7 KiB
C
125 lines
3.7 KiB
C
/*
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* PNG parser
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* Copyright (c) 2009 Peter Holik
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* PNG parser
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*/
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#include "libavutil/intreadwrite.h"
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#include "libavutil/common.h"
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#include "parser.h"
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#define PNG_SIGNATURE UINT64_C(0x89504e470d0a1a0a)
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#define MNG_SIGNATURE UINT64_C(0x8a4d4e470d0a1a0a)
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typedef struct PNGParseContext {
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ParseContext pc;
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int chunk_pos; ///< position inside current chunk
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int chunk_length; ///< length of the current chunk
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int remaining_size; ///< remaining size of the current chunk
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} PNGParseContext;
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static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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PNGParseContext *ppc = s->priv_data;
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int next = END_NOT_FOUND;
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int i = 0;
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*poutbuf_size = 0;
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if (buf_size == 0)
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return 0;
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if (!ppc->pc.frame_start_found) {
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uint64_t state64 = ppc->pc.state64;
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for (; i < buf_size; i++) {
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state64 = (state64 << 8) | buf[i];
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if (state64 == PNG_SIGNATURE ||
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state64 == MNG_SIGNATURE) {
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i++;
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ppc->pc.frame_start_found = 1;
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break;
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}
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}
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ppc->pc.state64 = state64;
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} else if (ppc->remaining_size) {
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i = FFMIN(ppc->remaining_size, buf_size);
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ppc->remaining_size -= i;
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if (ppc->remaining_size)
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goto flush;
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if (ppc->chunk_pos == -1) {
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next = i;
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goto flush;
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}
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}
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for (; ppc->pc.frame_start_found && i < buf_size; i++) {
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ppc->pc.state = (ppc->pc.state << 8) | buf[i];
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if (ppc->chunk_pos == 3) {
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ppc->chunk_length = ppc->pc.state;
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if (ppc->chunk_length > 0x7fffffff) {
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ppc->chunk_pos = ppc->pc.frame_start_found = 0;
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goto flush;
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}
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ppc->chunk_length += 4;
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} else if (ppc->chunk_pos == 7) {
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if (ppc->chunk_length >= buf_size - i)
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ppc->remaining_size = ppc->chunk_length - buf_size + i + 1;
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if (ppc->pc.state == MKBETAG('I', 'E', 'N', 'D')) {
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if (ppc->remaining_size)
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ppc->chunk_pos = -1;
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else
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next = ppc->chunk_length + i + 1;
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break;
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} else {
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ppc->chunk_pos = 0;
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if (ppc->remaining_size)
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break;
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else
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i += ppc->chunk_length;
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continue;
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}
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}
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ppc->chunk_pos++;
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}
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flush:
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if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0)
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return buf_size;
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ppc->chunk_pos = ppc->pc.frame_start_found = 0;
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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AVCodecParser ff_png_parser = {
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.codec_ids = { AV_CODEC_ID_PNG },
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.priv_data_size = sizeof(PNGParseContext),
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.parser_parse = png_parse,
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.parser_close = ff_parse_close,
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};
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