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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 "parser.h" //for ParseContext
23 #include "pnm.h"
24 
25 
27  const uint8_t **poutbuf, int *poutbuf_size,
28  const uint8_t *buf, int buf_size)
29 {
30  ParseContext *pc = s->priv_data;
31  PNMContext pnmctx;
32  int next;
33 
34  for (; pc->overread > 0; pc->overread--) {
35  pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
36  }
37 retry:
38  if (pc->index) {
39  pnmctx.bytestream_start =
40  pnmctx.bytestream = pc->buffer;
41  pnmctx.bytestream_end = pc->buffer + pc->index;
42  } else {
43  pnmctx.bytestream_start =
44  pnmctx.bytestream = (uint8_t *) buf; /* casts avoid warnings */
45  pnmctx.bytestream_end = (uint8_t *) buf + buf_size;
46  }
47  if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
48  if (pnmctx.bytestream < pnmctx.bytestream_end) {
49  if (pc->index) {
50  pc->index = 0;
51  } else {
52  buf++;
53  buf_size--;
54  }
55  goto retry;
56  }
57 #if 0
58  if (pc->index && pc->index * 2 + AV_INPUT_BUFFER_PADDING_SIZE < pc->buffer_size && buf_size > pc->index) {
59  memcpy(pc->buffer + pc->index, buf, pc->index);
60  pc->index += pc->index;
61  buf += pc->index;
62  buf_size -= pc->index;
63  goto retry;
64  }
65 #endif
66  next = END_NOT_FOUND;
67  } else {
68  next = pnmctx.bytestream - pnmctx.bytestream_start
69  + avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
70  if (pnmctx.bytestream_start != buf)
71  next -= pc->index;
72  if (next > buf_size)
73  next = END_NOT_FOUND;
74  }
75 
76  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
77  *poutbuf = NULL;
78  *poutbuf_size = 0;
79  return buf_size;
80  }
81  *poutbuf = buf;
82  *poutbuf_size = buf_size;
83  return next;
84 }
85 
89  .priv_data_size = sizeof(ParseContext),
90  .parser_parse = pnm_parse,
91  .parser_close = ff_parse_close,
92 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
int codec_ids[5]
Definition: avcodec.h:4718
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1722
uint8_t * bytestream
Definition: pnm.h:28
AVCodecParser ff_pnm_parser
Definition: pnm_parser.c:86
uint8_t
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:231
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:307
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:1681
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:1502
void * buf
Definition: avisynth_c.h:553
#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:26
int index
Definition: parser.h:30
uint8_t * bytestream_start
Definition: pnm.h:29
int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height)
Calculate the size in bytes that a picture of the given width and height would occupy if stored in th...
Definition: avpicture.c:49