avfilter/f_loop: warn about unset loop sizes
[ffmpeg.git] / libavcodec / dvbsub_parser.c
1 /*
2  * DVB subtitle parser for FFmpeg
3  * Copyright (c) 2005 Ian Caulfield
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 <inttypes.h>
23 #include <string.h>
24
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/mem.h"
27
28 #include "avcodec.h"
29 #include "internal.h"
30
31 /* Parser (mostly) copied from dvdsub.c */
32
33 #define PARSE_BUF_SIZE  (65536)
34
35
36 /* parser definition */
37 typedef struct DVBSubParseContext {
38     uint8_t *packet_buf;
39     int packet_start;
40     int packet_index;
41     int in_packet;
42 } DVBSubParseContext;
43
44 static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
45 {
46     DVBSubParseContext *pc = s->priv_data;
47     pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
48
49     return 0;
50 }
51
52 static int dvbsub_parse(AVCodecParserContext *s,
53                         AVCodecContext *avctx,
54                         const uint8_t **poutbuf, int *poutbuf_size,
55                         const uint8_t *buf, int buf_size)
56 {
57     DVBSubParseContext *pc = s->priv_data;
58     uint8_t *p, *p_end;
59     int i, len, buf_pos = 0;
60     int out_size = 0;
61
62     ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
63             s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
64
65     for (i=0; i < buf_size; i++)
66     {
67         ff_dlog(avctx, "%02x ", buf[i]);
68         if (i % 16 == 15)
69             ff_dlog(avctx, "\n");
70     }
71
72     if (i % 16 != 0)
73         ff_dlog(avctx, "\n");
74
75     *poutbuf      = buf;
76     *poutbuf_size = buf_size;
77
78     s->fetch_timestamp = 1;
79
80     if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
81     {
82         if (pc->packet_index != pc->packet_start)
83         {
84             ff_dlog(avctx, "Discarding %d bytes\n",
85                     pc->packet_index - pc->packet_start);
86         }
87
88         pc->packet_start = 0;
89         pc->packet_index = 0;
90
91         if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
92             ff_dlog(avctx, "Bad packet header\n");
93             return buf_size;
94         }
95
96         buf_pos = 2;
97
98         pc->in_packet = 1;
99     } else {
100         if (pc->packet_start != 0)
101         {
102             if (pc->packet_index != pc->packet_start)
103             {
104                 memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
105                             pc->packet_index - pc->packet_start);
106
107                 pc->packet_index -= pc->packet_start;
108                 pc->packet_start = 0;
109             } else {
110                 pc->packet_start = 0;
111                 pc->packet_index = 0;
112             }
113         }
114     }
115
116     if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
117         return buf_size;
118
119 /* if not currently in a packet, pass data */
120     if (pc->in_packet == 0)
121         return buf_size;
122
123     memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
124     pc->packet_index += buf_size - buf_pos;
125
126     p = pc->packet_buf;
127     p_end = pc->packet_buf + pc->packet_index;
128
129     while (p < p_end)
130     {
131         if (*p == 0x0f)
132         {
133             if (6 <= p_end - p)
134             {
135                 len = AV_RB16(p + 4);
136
137                 if (len + 6 <= p_end - p)
138                 {
139                     out_size += len + 6;
140
141                     p += len + 6;
142                 } else
143                     break;
144             } else
145                 break;
146         } else if (*p == 0xff) {
147             if (1 < p_end - p)
148             {
149                 ff_dlog(avctx, "Junk at end of packet\n");
150             }
151             pc->packet_index = p - pc->packet_buf;
152             pc->in_packet = 0;
153             break;
154         } else {
155             av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
156
157             pc->packet_index = p - pc->packet_buf;
158             pc->in_packet = 0;
159             break;
160         }
161     }
162
163     if (out_size > 0)
164     {
165         *poutbuf = pc->packet_buf;
166         *poutbuf_size = out_size;
167         pc->packet_start = *poutbuf_size;
168     }
169
170     if (s->pts == AV_NOPTS_VALUE)
171         s->pts = s->last_pts;
172
173     return buf_size;
174 }
175
176 static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
177 {
178     DVBSubParseContext *pc = s->priv_data;
179     av_freep(&pc->packet_buf);
180 }
181
182 AVCodecParser ff_dvbsub_parser = {
183     .codec_ids      = { AV_CODEC_ID_DVB_SUBTITLE },
184     .priv_data_size = sizeof(DVBSubParseContext),
185     .parser_init    = dvbsub_parse_init,
186     .parser_parse   = dvbsub_parse,
187     .parser_close   = dvbsub_parse_close,
188 };