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pnm_parser.c
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1 /*
2  * PNM image parser
3  * Copyright (c) 2002, 2003 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/imgutils.h"
23 
24 #include "parser.h" //for ParseContext
25 #include "pnm.h"
26 
27 
29  const uint8_t **poutbuf, int *poutbuf_size,
30  const uint8_t *buf, int buf_size)
31 {
32  ParseContext *pc = s->priv_data;
33  PNMContext pnmctx;
34  int next;
35 
36  for (; pc->overread > 0; pc->overread--) {
37  pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
38  }
39 retry:
40  if (pc->index) {
41  pnmctx.bytestream_start =
42  pnmctx.bytestream = pc->buffer;
43  pnmctx.bytestream_end = pc->buffer + pc->index;
44  } else {
45  pnmctx.bytestream_start =
46  pnmctx.bytestream = (uint8_t *) buf; /* casts avoid warnings */
47  pnmctx.bytestream_end = (uint8_t *) buf + buf_size;
48  }
49  if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
50  if (pnmctx.bytestream < pnmctx.bytestream_end) {
51  if (pc->index) {
52  pc->index = 0;
53  } else {
54  buf++;
55  buf_size--;
56  }
57  goto retry;
58  }
59  next = END_NOT_FOUND;
60  } else if (pnmctx.type < 4) {
61  next = END_NOT_FOUND;
62  } else {
63  next = pnmctx.bytestream - pnmctx.bytestream_start
64  + av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);
65  if (pnmctx.bytestream_start != buf)
66  next -= pc->index;
67  if (next > buf_size)
68  next = END_NOT_FOUND;
69  }
70 
71  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
72  *poutbuf = NULL;
73  *poutbuf_size = 0;
74  return buf_size;
75  }
76  *poutbuf = buf;
77  *poutbuf_size = buf_size;
78  return next;
79 }
80 
84  .priv_data_size = sizeof(ParseContext),
85  .parser_parse = pnm_parse,
86  .parser_close = ff_parse_close,
87 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
misc image utilities
int codec_ids[5]
Definition: avcodec.h:5233
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1950
uint8_t * bytestream
Definition: pnm.h:28
AVCodecParser ff_pnm_parser
Definition: pnm_parser.c:81
uint8_t
int av_image_get_buffer_size(enum AVPixelFormat pix_fmt, int width, int height, int align)
Return the size in bytes of the amount of data required to store an image with the given parameters...
Definition: imgutils.c:429
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:250
int overread_index
the index into ParseContext.buffer of the overread bytes
Definition: parser.h:36
uint8_t * bytestream_end
Definition: pnm.h:30
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:326
int overread
the number of bytes which where irreversibly read from the next frame
Definition: parser.h:35
int width
picture width / height.
Definition: avcodec.h:1909
Definition: pnm.h:27
uint8_t * buffer
Definition: parser.h:29
int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext *const s)
Definition: pnm.c:60
main external API structure.
Definition: avcodec.h:1722
void * buf
Definition: avisynth_c.h:690
#define END_NOT_FOUND
Definition: parser.h:40
static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: pnm_parser.c:28
int index
Definition: parser.h:30
uint8_t * bytestream_start
Definition: pnm.h:29
int type
Definition: pnm.h:32