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1 /*
2  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 #include "avformat.h"
21 #include "avio_internal.h"
22 #include "internal.h"
23 
24 #include "libavutil/avassert.h"
25 #include "libavutil/internal.h"
26 #include "libavutil/opt.h"
27 
28 /**
29  * @file
30  * Options definition for AVFormatContext.
31  */
32 
33 FF_DISABLE_DEPRECATION_WARNINGS
34 #include "options_table.h"
35 FF_ENABLE_DEPRECATION_WARNINGS
36 
format_to_name(void * ptr)37 static const char* format_to_name(void* ptr)
38 {
39     AVFormatContext* fc = (AVFormatContext*) ptr;
40     if(fc->iformat) return fc->iformat->name;
41     else if(fc->oformat) return fc->oformat->name;
42     else return "NULL";
43 }
44 
format_child_next(void * obj,void * prev)45 static void *format_child_next(void *obj, void *prev)
46 {
47     AVFormatContext *s = obj;
48     if (!prev && s->priv_data &&
49         ((s->iformat && s->iformat->priv_class) ||
50           s->oformat && s->oformat->priv_class))
51         return s->priv_data;
52     if (s->pb && s->pb->av_class && prev != s->pb)
53         return s->pb;
54     return NULL;
55 }
56 
57 #if FF_API_CHILD_CLASS_NEXT
format_child_class_next(const AVClass * prev)58 static const AVClass *format_child_class_next(const AVClass *prev)
59 {
60     const AVInputFormat *ifmt = NULL;
61     const AVOutputFormat *ofmt = NULL;
62     void *ifmt_iter = NULL, *ofmt_iter = NULL;
63 
64     if (!prev)
65         return &ff_avio_class;
66 
67     while ((ifmt = av_demuxer_iterate(&ifmt_iter)))
68         if (ifmt->priv_class == prev)
69             break;
70 
71     if (!ifmt) {
72         ifmt_iter = NULL;
73         while ((ofmt = av_muxer_iterate(&ofmt_iter)))
74             if (ofmt->priv_class == prev)
75                 break;
76     }
77     if (!ofmt) {
78         ofmt_iter = NULL;
79         while ((ifmt = av_demuxer_iterate(&ifmt_iter)))
80             if (ifmt->priv_class)
81                 return ifmt->priv_class;
82     }
83 
84     while ((ofmt = av_muxer_iterate(&ofmt_iter)))
85         if (ofmt->priv_class)
86             return ofmt->priv_class;
87 
88     return NULL;
89 }
90 #endif
91 
92 enum {
93     CHILD_CLASS_ITER_AVIO = 0,
94     CHILD_CLASS_ITER_MUX,
95     CHILD_CLASS_ITER_DEMUX,
96     CHILD_CLASS_ITER_DONE,
97 
98 };
99 
100 #define ITER_STATE_SHIFT 16
101 
format_child_class_iterate(void ** iter)102 static const AVClass *format_child_class_iterate(void **iter)
103 {
104     // we use the low 16 bits of iter as the value to be passed to
105     // av_(de)muxer_iterate()
106     void *val = (void*)(((uintptr_t)*iter) & ((1 << ITER_STATE_SHIFT) - 1));
107     unsigned int state = ((uintptr_t)*iter) >> ITER_STATE_SHIFT;
108     const AVClass *ret = NULL;
109 
110     if (state == CHILD_CLASS_ITER_AVIO) {
111         ret = &ff_avio_class;
112         state++;
113         goto finish;
114     }
115 
116     if (state == CHILD_CLASS_ITER_MUX) {
117         const AVOutputFormat *ofmt;
118 
119         while ((ofmt = av_muxer_iterate(&val))) {
120             ret = ofmt->priv_class;
121             if (ret)
122                 goto finish;
123         }
124 
125         val = NULL;
126         state++;
127     }
128 
129     if (state == CHILD_CLASS_ITER_DEMUX) {
130         const AVInputFormat *ifmt;
131 
132         while ((ifmt = av_demuxer_iterate(&val))) {
133             ret = ifmt->priv_class;
134             if (ret)
135                 goto finish;
136         }
137         val = NULL;
138         state++;
139     }
140 
141 finish:
142     // make sure none av_(de)muxer_iterate does not set the high bits of val
143     av_assert0(!((uintptr_t)val >> ITER_STATE_SHIFT));
144     *iter = (void*)((uintptr_t)val | (state << ITER_STATE_SHIFT));
145     return ret;
146 }
147 
get_category(void * ptr)148 static AVClassCategory get_category(void *ptr)
149 {
150     AVFormatContext* s = ptr;
151     if(s->iformat) return AV_CLASS_CATEGORY_DEMUXER;
152     else           return AV_CLASS_CATEGORY_MUXER;
153 }
154 
155 static const AVClass av_format_context_class = {
156     .class_name     = "AVFormatContext",
157     .item_name      = format_to_name,
158     .option         = avformat_options,
159     .version        = LIBAVUTIL_VERSION_INT,
160     .child_next     = format_child_next,
161 #if FF_API_CHILD_CLASS_NEXT
162     .child_class_next = format_child_class_next,
163 #endif
164     .child_class_iterate = format_child_class_iterate,
165     .category       = AV_CLASS_CATEGORY_MUXER,
166     .get_category   = get_category,
167 };
168 
io_open_default(AVFormatContext * s,AVIOContext ** pb,const char * url,int flags,AVDictionary ** options)169 static int io_open_default(AVFormatContext *s, AVIOContext **pb,
170                            const char *url, int flags, AVDictionary **options)
171 {
172     int loglevel;
173 
174     if (!strcmp(url, s->url) ||
175         s->iformat && !strcmp(s->iformat->name, "image2") ||
176         s->oformat && !strcmp(s->oformat->name, "image2")
177     ) {
178         loglevel = AV_LOG_DEBUG;
179     } else
180         loglevel = AV_LOG_INFO;
181 
182     av_log(s, loglevel, "Opening \'%s\' for %s\n", url, flags & AVIO_FLAG_WRITE ? "writing" : "reading");
183 
184 #if FF_API_OLD_OPEN_CALLBACKS
185 FF_DISABLE_DEPRECATION_WARNINGS
186     if (s->open_cb)
187         return s->open_cb(s, pb, url, flags, &s->interrupt_callback, options);
188 FF_ENABLE_DEPRECATION_WARNINGS
189 #endif
190 
191     return ffio_open_whitelist(pb, url, flags, &s->interrupt_callback, options, s->protocol_whitelist, s->protocol_blacklist);
192 }
193 
io_close_default(AVFormatContext * s,AVIOContext * pb)194 static void io_close_default(AVFormatContext *s, AVIOContext *pb)
195 {
196     avio_close(pb);
197 }
198 
avformat_get_context_defaults(AVFormatContext * s)199 static void avformat_get_context_defaults(AVFormatContext *s)
200 {
201     memset(s, 0, sizeof(AVFormatContext));
202 
203     s->av_class = &av_format_context_class;
204 
205     s->io_open  = io_open_default;
206     s->io_close = io_close_default;
207 
208     av_opt_set_defaults(s);
209 }
210 
avformat_alloc_context(void)211 AVFormatContext *avformat_alloc_context(void)
212 {
213     AVFormatContext *ic;
214     AVFormatInternal *internal;
215     ic = av_malloc(sizeof(AVFormatContext));
216     if (!ic) return ic;
217 
218     internal = av_mallocz(sizeof(*internal));
219     if (!internal) {
220         av_free(ic);
221         return NULL;
222     }
223     internal->pkt = av_packet_alloc();
224     internal->parse_pkt = av_packet_alloc();
225     if (!internal->pkt || !internal->parse_pkt) {
226         av_packet_free(&internal->pkt);
227         av_packet_free(&internal->parse_pkt);
228         av_free(internal);
229         av_free(ic);
230         return NULL;
231     }
232     avformat_get_context_defaults(ic);
233     ic->internal = internal;
234     ic->internal->offset = AV_NOPTS_VALUE;
235     ic->internal->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;
236     ic->internal->shortest_end = AV_NOPTS_VALUE;
237 
238     return ic;
239 }
240 
av_fmt_ctx_get_duration_estimation_method(const AVFormatContext * ctx)241 enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx)
242 {
243     return ctx->duration_estimation_method;
244 }
245 
avformat_get_class(void)246 const AVClass *avformat_get_class(void)
247 {
248     return &av_format_context_class;
249 }
250