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FFmpeg/libavcodec/pnm_parser.c

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/*
* PNM image parser
* Copyright (c) 2002, 2003 Fabrice Bellard.
*
* 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
*/
#include "parser.h" //for ParseContext
#include "pnm.h"
static int pnm_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
ParseContext *pc = s->priv_data;
PNMContext pnmctx;
int next;
for(; pc->overread>0; pc->overread--){
pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
}
retry:
if(pc->index){
pnmctx.bytestream_start=
pnmctx.bytestream= pc->buffer;
pnmctx.bytestream_end= pc->buffer + pc->index;
}else{
pnmctx.bytestream_start=
pnmctx.bytestream= (uint8_t *) buf; /* casts avoid warnings */
pnmctx.bytestream_end= (uint8_t *) buf + buf_size;
}
if(ff_pnm_decode_header(avctx, &pnmctx) < 0){
if(pnmctx.bytestream < pnmctx.bytestream_end){
if(pc->index){
pc->index=0;
}else{
buf++;
buf_size--;
}
goto retry;
}
#if 0
if(pc->index && pc->index*2 + FF_INPUT_BUFFER_PADDING_SIZE < pc->buffer_size && buf_size > pc->index){
memcpy(pc->buffer + pc->index, buf, pc->index);
pc->index += pc->index;
buf += pc->index;
buf_size -= pc->index;
goto retry;
}
#endif
next= END_NOT_FOUND;
}else{
next= pnmctx.bytestream - pnmctx.bytestream_start
+ avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
if(pnmctx.bytestream_start!=buf)
next-= pc->index;
if(next > buf_size)
next= END_NOT_FOUND;
}
if(ff_combine_frame(pc, next, &buf, &buf_size)<0){
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
AVCodecParser pnm_parser = {
{ CODEC_ID_PGM, CODEC_ID_PGMYUV, CODEC_ID_PPM, CODEC_ID_PBM, CODEC_ID_PAM},
sizeof(ParseContext),
NULL,
pnm_parse,
ff_parse_close,
};