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dpx_parser.c
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1 /*
2  * DPX parser
3  * Copyright (c) 2013 Paul B Mahol
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 /**
23  * @file
24  * DPX parser
25  */
26 
27 #include "libavutil/bswap.h"
28 #include "parser.h"
29 
30 typedef struct DPXParseContext {
32  uint32_t index;
33  uint32_t fsize;
34  uint32_t remaining_size;
35  int is_be;
37 
39  const uint8_t **poutbuf, int *poutbuf_size,
40  const uint8_t *buf, int buf_size)
41 {
42  DPXParseContext *d = s->priv_data;
43  uint32_t state = d->pc.state;
44  int next = END_NOT_FOUND;
45  int i = 0;
46 
48 
49  *poutbuf_size = 0;
50  if (buf_size == 0)
51  return 0;
52 
53  if (!d->pc.frame_start_found) {
54  for (; i < buf_size; i++) {
55  state = (state << 8) | buf[i];
56  if (state == MKBETAG('S','D','P','X') ||
57  state == MKTAG('S','D','P','X')) {
58  d->pc.frame_start_found = 1;
59  d->is_be = state == MKBETAG('S','D','P','X');
60  break;
61  }
62  }
63  d->pc.state = state;
64  } else {
65  if (d->remaining_size) {
66  i = FFMIN(d->remaining_size, buf_size);
67  d->remaining_size -= i;
68  if (d->remaining_size)
69  goto flush;
70  next = i;
71  }
72  }
73 
74  for (;d->pc.frame_start_found && i < buf_size; i++) {
75  d->pc.state = (d->pc.state << 8) | buf[i];
76  if (d->index == 16) {
77  d->fsize = d->is_be ? d->pc.state : av_bswap32(d->pc.state);
78  if (d->fsize <= 1664) {
79  d->index = d->pc.frame_start_found = 0;
80  goto flush;
81  }
82  d->index = 0;
83  if (d->fsize > buf_size - i + 19)
84  d->remaining_size = d->fsize - buf_size + i - 19;
85  else
86  next = d->fsize + i - 19;
87  break;
88  }
89  d->index++;
90  }
91 
92 flush:
93  if (ff_combine_frame(&d->pc, next, &buf, &buf_size) < 0)
94  return buf_size;
95 
96  d->index = d->pc.frame_start_found = 0;
97 
98  *poutbuf = buf;
99  *poutbuf_size = buf_size;
100  return next;
101 }
102 
104  .codec_ids = { AV_CODEC_ID_DPX },
105  .priv_data_size = sizeof(DPXParseContext),
106  .parser_parse = dpx_parse,
107  .parser_close = ff_parse_close,
108 };