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libavcodec/pnm_parser.c

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00001 /*
00002  * PNM image parser
00003  * Copyright (c) 2002, 2003 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "parser.h" //for ParseContext
00023 #include "pnm.h"
00024 
00025 
00026 static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx,
00027                      const uint8_t **poutbuf, int *poutbuf_size,
00028                      const uint8_t *buf, int buf_size)
00029 {
00030     ParseContext *pc = s->priv_data;
00031     PNMContext pnmctx;
00032     int next;
00033 
00034     for (; pc->overread > 0; pc->overread--) {
00035         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
00036     }
00037 retry:
00038     if (pc->index) {
00039         pnmctx.bytestream_start =
00040         pnmctx.bytestream       = pc->buffer;
00041         pnmctx.bytestream_end   = pc->buffer + pc->index;
00042     } else {
00043         pnmctx.bytestream_start =
00044         pnmctx.bytestream       = (uint8_t *) buf; /* casts avoid warnings */
00045         pnmctx.bytestream_end   = (uint8_t *) buf + buf_size;
00046     }
00047     if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
00048         if (pnmctx.bytestream < pnmctx.bytestream_end) {
00049             if (pc->index) {
00050                 pc->index = 0;
00051             } else {
00052                 buf++;
00053                 buf_size--;
00054             }
00055             goto retry;
00056         }
00057 #if 0
00058         if (pc->index && pc->index * 2 + FF_INPUT_BUFFER_PADDING_SIZE < pc->buffer_size && buf_size > pc->index) {
00059             memcpy(pc->buffer + pc->index, buf, pc->index);
00060             pc->index += pc->index;
00061             buf       += pc->index;
00062             buf_size  -= pc->index;
00063             goto retry;
00064         }
00065 #endif
00066         next = END_NOT_FOUND;
00067     } else {
00068         next = pnmctx.bytestream - pnmctx.bytestream_start
00069                + avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
00070         if (pnmctx.bytestream_start != buf)
00071             next -= pc->index;
00072         if (next > buf_size)
00073             next = END_NOT_FOUND;
00074     }
00075 
00076     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
00077         *poutbuf      = NULL;
00078         *poutbuf_size = 0;
00079         return buf_size;
00080     }
00081     *poutbuf      = buf;
00082     *poutbuf_size = buf_size;
00083     return next;
00084 }
00085 
00086 AVCodecParser pnm_parser = {
00087     { CODEC_ID_PGM, CODEC_ID_PGMYUV, CODEC_ID_PPM, CODEC_ID_PBM, CODEC_ID_PAM},
00088     sizeof(ParseContext),
00089     NULL,
00090     pnm_parse,
00091     ff_parse_close,
00092 };

Generated on Fri Sep 16 2011 17:17:41 for FFmpeg by  doxygen 1.7.1