ffmpeg/libavcodec/png_parser.c

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/*
* PNG parser
* Copyright (c) 2009 Peter Holik
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
2012-05-04 16:50:11 +00:00
* @file
* PNG parser
*/
#include "parser.h"
#include "png.h"
typedef struct PNGParseContext
{
ParseContext pc;
uint32_t index;
uint32_t chunk_length;
uint32_t remaining_size;
} PNGParseContext;
static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
PNGParseContext *ppc = s->priv_data;
int next = END_NOT_FOUND;
int i = 0;
s->pict_type = AV_PICTURE_TYPE_NONE;
*poutbuf_size = 0;
if (buf_size == 0)
return 0;
if (!ppc->pc.frame_start_found) {
uint64_t state64 = ppc->pc.state64;
for (; i < buf_size; i++) {
state64 = (state64 << 8) | buf[i];
if (state64 == PNGSIG || state64 == MNGSIG) {
i++;
ppc->pc.frame_start_found = 1;
break;
}
}
ppc->pc.state64 = state64;
} else
if (ppc->remaining_size) {
i = FFMIN(ppc->remaining_size, buf_size);
ppc->remaining_size -= i;
if (ppc->remaining_size)
goto flush;
if (ppc->index == -1) {
next = i;
goto flush;
}
}
for (;ppc->pc.frame_start_found && i < buf_size; i++) {
ppc->pc.state = (ppc->pc.state<<8) | buf[i];
if (ppc->index == 3) {
ppc->chunk_length = ppc->pc.state;
if (ppc->chunk_length > 0x7fffffff) {
ppc->index = ppc->pc.frame_start_found = 0;
goto flush;
}
ppc->chunk_length += 4;
} else if (ppc->index == 7) {
if (ppc->chunk_length >= buf_size - i)
ppc->remaining_size = ppc->chunk_length - buf_size + i + 1;
if (ppc->pc.state == MKBETAG('I', 'E', 'N', 'D')) {
if (ppc->remaining_size)
ppc->index = -1;
else
next = ppc->chunk_length + i + 1;
break;
} else {
ppc->index = 0;
if (ppc->remaining_size)
break;
else
i += ppc->chunk_length;
continue;
}
}
ppc->index++;
}
flush:
if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0)
return buf_size;
ppc->index = ppc->pc.frame_start_found = 0;
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
AVCodecParser ff_png_parser = {
Merge commit '36ef5369ee9b336febc2c270f8718cec4476cb85' * commit '36ef5369ee9b336febc2c270f8718cec4476cb85': Replace all CODEC_ID_* with AV_CODEC_ID_* lavc: add AV prefix to codec ids. Conflicts: doc/APIchanges doc/examples/decoding_encoding.c doc/examples/muxing.c ffmpeg.c ffprobe.c ffserver.c libavcodec/8svx.c libavcodec/avcodec.h libavcodec/dnxhd_parser.c libavcodec/dvdsubdec.c libavcodec/error_resilience.c libavcodec/h263dec.c libavcodec/libvorbisenc.c libavcodec/mjpeg_parser.c libavcodec/mjpegenc.c libavcodec/mpeg12.c libavcodec/mpeg4videodec.c libavcodec/mpegvideo.c libavcodec/mpegvideo_enc.c libavcodec/pcm.c libavcodec/r210dec.c libavcodec/utils.c libavcodec/v210dec.c libavcodec/version.h libavdevice/alsa-audio-dec.c libavdevice/bktr.c libavdevice/v4l2.c libavformat/asfdec.c libavformat/asfenc.c libavformat/avformat.h libavformat/avidec.c libavformat/caf.c libavformat/electronicarts.c libavformat/flacdec.c libavformat/flvdec.c libavformat/flvenc.c libavformat/framecrcenc.c libavformat/img2.c libavformat/img2dec.c libavformat/img2enc.c libavformat/ipmovie.c libavformat/isom.c libavformat/matroska.c libavformat/matroskadec.c libavformat/matroskaenc.c libavformat/mov.c libavformat/movenc.c libavformat/mp3dec.c libavformat/mpeg.c libavformat/mpegts.c libavformat/mxf.c libavformat/mxfdec.c libavformat/mxfenc.c libavformat/nsvdec.c libavformat/nut.c libavformat/oggenc.c libavformat/pmpdec.c libavformat/rawdec.c libavformat/rawenc.c libavformat/riff.c libavformat/sdp.c libavformat/utils.c libavformat/vocenc.c libavformat/wtv.c libavformat/xmv.c Merged-by: Michael Niedermayer <michaelni@gmx.at>
2012-08-07 20:45:46 +00:00
.codec_ids = { AV_CODEC_ID_PNG },
.priv_data_size = sizeof(PNGParseContext),
.parser_parse = png_parse,
.parser_close = ff_parse_close,
};