mirror of https://git.ffmpeg.org/ffmpeg.git
90 lines
2.9 KiB
C
90 lines
2.9 KiB
C
/*
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* PNM image parser
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* Copyright (c) 2002, 2003 Fabrice Bellard
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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#include "libavutil/imgutils.h"
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#include "parser.h" //for ParseContext
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#include "pnm.h"
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static int pnm_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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ParseContext *pc = s->priv_data;
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PNMContext pnmctx;
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int next;
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int skip = 0;
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for (; pc->overread > 0; pc->overread--) {
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pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
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}
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retry:
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if (pc->index) {
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pnmctx.bytestream_start =
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pnmctx.bytestream = pc->buffer;
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pnmctx.bytestream_end = pc->buffer + pc->index;
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} else {
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pnmctx.bytestream_start =
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pnmctx.bytestream = (uint8_t *) buf + skip; /* casts avoid warnings */
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pnmctx.bytestream_end = (uint8_t *) buf + buf_size - skip;
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}
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if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
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if (pnmctx.bytestream < pnmctx.bytestream_end) {
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if (pc->index) {
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pc->index = 0;
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} else {
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unsigned step = FFMAX(1, pnmctx.bytestream - pnmctx.bytestream_start);
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skip += step;
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}
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goto retry;
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}
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next = END_NOT_FOUND;
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} else if (pnmctx.type < 4) {
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next = END_NOT_FOUND;
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} else {
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next = pnmctx.bytestream - pnmctx.bytestream_start + skip
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+ av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);
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if (pnmctx.bytestream_start != buf + skip)
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next -= pc->index;
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if (next > buf_size)
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next = END_NOT_FOUND;
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}
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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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_pnm_parser = {
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.codec_ids = { AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM,
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AV_CODEC_ID_PBM, AV_CODEC_ID_PAM },
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.priv_data_size = sizeof(ParseContext),
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.parser_parse = pnm_parse,
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.parser_close = ff_parse_close,
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};
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