1 /*
2 * XBM parser
3 * Copyright (c) 2021 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 * XBM parser
25 */
26
27 #include "libavutil/common.h"
28
29 #include "parser.h"
30
31 typedef struct XBMParseContext {
32 ParseContext pc;
33 uint16_t state16;
34 int count;
35 } XBMParseContext;
36
37 #define KEY (((uint64_t)'\n' << 56) | ((uint64_t)'#' << 48) | \
38 ((uint64_t)'d' << 40) | ((uint64_t)'e' << 32) | \
39 ((uint64_t)'f' << 24) | ('i' << 16) | ('n' << 8) | \
40 ('e' << 0))
41
42 #define END ((';' << 8) | ('\n' << 0))
43
xbm_init(AVCodecParserContext * s)44 static int xbm_init(AVCodecParserContext *s)
45 {
46 XBMParseContext *bpc = s->priv_data;
47
48 bpc->count = 1;
49
50 return 0;
51 }
52
xbm_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)53 static int xbm_parse(AVCodecParserContext *s, AVCodecContext *avctx,
54 const uint8_t **poutbuf, int *poutbuf_size,
55 const uint8_t *buf, int buf_size)
56 {
57 XBMParseContext *bpc = s->priv_data;
58 uint64_t state = bpc->pc.state64;
59 uint16_t state16 = bpc->state16;
60 int next = END_NOT_FOUND, i = 0;
61
62 s->pict_type = AV_PICTURE_TYPE_I;
63 s->key_frame = 1;
64 s->duration = 1;
65
66 *poutbuf_size = 0;
67 *poutbuf = NULL;
68
69 for (; i < buf_size; i++) {
70 state = (state << 8) | buf[i];
71 state16 = (state16 << 8) | buf[i];
72
73 if (state == KEY)
74 bpc->count++;
75
76 if ((state == KEY && bpc->count == 1)) {
77 next = i - 6;
78 break;
79 } else if (state16 == END) {
80 next = i + 1;
81 bpc->count = 0;
82 break;
83 }
84 }
85
86 bpc->pc.state64 = state;
87 bpc->state16 = state16;
88 if (ff_combine_frame(&bpc->pc, next, &buf, &buf_size) < 0) {
89 *poutbuf = NULL;
90 *poutbuf_size = 0;
91 return buf_size;
92 }
93
94 *poutbuf = buf;
95 *poutbuf_size = buf_size;
96
97 return next;
98 }
99
100 AVCodecParser ff_xbm_parser = {
101 .codec_ids = { AV_CODEC_ID_XBM },
102 .priv_data_size = sizeof(XBMParseContext),
103 .parser_init = xbm_init,
104 .parser_parse = xbm_parse,
105 .parser_close = ff_parse_close,
106 };
107