Add AVSEEK_FORCE flag to indicate that the code should attempt to seek
[libav.git] / libavformat / avio.h
1 /*
2 * copyright (c) 2001 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 #ifndef AVFORMAT_AVIO_H
21 #define AVFORMAT_AVIO_H
22
23 /**
24 * @file libavformat/avio.h
25 * unbuffered I/O operations
26 *
27 * @warning This file has to be considered an internal but installed
28 * header, so it should not be directly included in your projects.
29 */
30
31 #include <stdint.h>
32
33 #include "libavutil/common.h"
34
35 /* unbuffered I/O */
36
37 /**
38 * URL Context.
39 * New fields can be added to the end with minor version bumps.
40 * Removal, reordering and changes to existing fields require a major
41 * version bump.
42 * sizeof(URLContext) must not be used outside libav*.
43 */
44 typedef struct URLContext {
45 #if LIBAVFORMAT_VERSION_MAJOR >= 53
46 const AVClass *av_class; ///< information for av_log(). Set by url_open().
47 #endif
48 struct URLProtocol *prot;
49 int flags;
50 int is_streamed; /**< true if streamed (no seek possible), default = false */
51 int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
52 void *priv_data;
53 char *filename; /**< specified URL */
54 } URLContext;
55
56 typedef struct URLPollEntry {
57 URLContext *handle;
58 int events;
59 int revents;
60 } URLPollEntry;
61
62 #define URL_RDONLY 0
63 #define URL_WRONLY 1
64 #define URL_RDWR 2
65
66 typedef int URLInterruptCB(void);
67
68 /**
69 * Creates an URLContext for accessing to the resource indicated by
70 * url, and opens it using the URLProtocol up.
71 *
72 * @param puc pointer to the location where, in case of success, the
73 * function puts the pointer to the created URLContext
74 * @param flags flags which control how the resource indicated by url
75 * is to be opened
76 * @return 0 in case of success, a negative value corresponding to an
77 * AVERROR code in case of failure
78 */
79 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
80 const char *url, int flags);
81
82 /**
83 * Creates an URLContext for accessing to the resource indicated by
84 * url, and opens it.
85 *
86 * @param puc pointer to the location where, in case of success, the
87 * function puts the pointer to the created URLContext
88 * @param flags flags which control how the resource indicated by url
89 * is to be opened
90 * @return 0 in case of success, a negative value corresponding to an
91 * AVERROR code in case of failure
92 */
93 int url_open(URLContext **h, const char *url, int flags);
94
95 /**
96 * Reads up to size bytes from the resource accessed by h, and stores
97 * the read bytes in buf.
98 *
99 * @return The number of bytes actually read, or a negative value
100 * corresponding to an AVERROR code in case of error. A value of zero
101 * indicates that it is not possible to read more from the accessed
102 * resource (except if the value of the size argument is also zero).
103 */
104 int url_read(URLContext *h, unsigned char *buf, int size);
105
106 /**
107 * Read as many bytes as possible (up to size), calling the
108 * read function multiple times if necessary.
109 * Will also retry if the read function returns AVERROR(EAGAIN).
110 * This makes special short-read handling in applications
111 * unnecessary, if the return value is < size then it is
112 * certain there was either an error or the end of file was reached.
113 */
114 int url_read_complete(URLContext *h, unsigned char *buf, int size);
115 int url_write(URLContext *h, unsigned char *buf, int size);
116 int64_t url_seek(URLContext *h, int64_t pos, int whence);
117
118 /**
119 * Closes the resource accessed by the URLContext h, and frees the
120 * memory used by it.
121 *
122 * @return a negative value if an error condition occurred, 0
123 * otherwise
124 */
125 int url_close(URLContext *h);
126
127 int url_exist(const char *url);
128 int64_t url_filesize(URLContext *h);
129
130 /**
131 * Return the file descriptor associated with this URL. For RTP, this
132 * will return only the RTP file descriptor, not the RTCP file descriptor.
133 * To get both, use rtp_get_file_handles().
134 *
135 * @return the file descriptor associated with this URL, or <0 on error.
136 */
137 int url_get_file_handle(URLContext *h);
138
139 /**
140 * Return the maximum packet size associated to packetized file
141 * handle. If the file is not packetized (stream like HTTP or file on
142 * disk), then 0 is returned.
143 *
144 * @param h file handle
145 * @return maximum packet size in bytes
146 */
147 int url_get_max_packet_size(URLContext *h);
148 void url_get_filename(URLContext *h, char *buf, int buf_size);
149
150 /**
151 * The callback is called in blocking functions to test regulary if
152 * asynchronous interruption is needed. AVERROR(EINTR) is returned
153 * in this case by the interrupted function. 'NULL' means no interrupt
154 * callback is given.
155 */
156 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
157
158 /* not implemented */
159 int url_poll(URLPollEntry *poll_table, int n, int timeout);
160
161 /**
162 * Pause and resume playing - only meaningful if using a network streaming
163 * protocol (e.g. MMS).
164 * @param pause 1 for pause, 0 for resume
165 */
166 int av_url_read_pause(URLContext *h, int pause);
167
168 /**
169 * Seek to a given timestamp relative to some component stream.
170 * Only meaningful if using a network streaming protocol (e.g. MMS.).
171 * @param stream_index The stream index that the timestamp is relative to.
172 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
173 * units from the beginning of the presentation.
174 * If a stream_index >= 0 is used and the protocol does not support
175 * seeking based on component streams, the call will fail with ENOTSUP.
176 * @param timestamp timestamp in AVStream.time_base units
177 * or if there is no stream specified then in AV_TIME_BASE units.
178 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
179 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
180 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
181 * fail with ENOTSUP if used and not supported.
182 * @return >= 0 on success
183 * @see AVInputFormat::read_seek
184 */
185 int64_t av_url_read_seek(URLContext *h, int stream_index,
186 int64_t timestamp, int flags);
187
188 /**
189 * Passing this as the "whence" parameter to a seek function causes it to
190 * return the filesize without seeking anywhere. Supporting this is optional.
191 * If it is not supported then the seek function will return <0.
192 */
193 #define AVSEEK_SIZE 0x10000
194
195 /**
196 * Oring this flag as into the "whence" parameter to a seek function causes it to
197 * seek by any means (like reopening and linear reading) or other normally unreasonble
198 * means that can be extreemly slow.
199 * This may be ignored by the seek code.
200 */
201 #define AVSEEK_FORCE 0x20000
202
203 typedef struct URLProtocol {
204 const char *name;
205 int (*url_open)(URLContext *h, const char *url, int flags);
206 int (*url_read)(URLContext *h, unsigned char *buf, int size);
207 int (*url_write)(URLContext *h, unsigned char *buf, int size);
208 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
209 int (*url_close)(URLContext *h);
210 struct URLProtocol *next;
211 int (*url_read_pause)(URLContext *h, int pause);
212 int64_t (*url_read_seek)(URLContext *h, int stream_index,
213 int64_t timestamp, int flags);
214 int (*url_get_file_handle)(URLContext *h);
215 } URLProtocol;
216
217 #if LIBAVFORMAT_VERSION_MAJOR < 53
218 extern URLProtocol *first_protocol;
219 #endif
220
221 extern URLInterruptCB *url_interrupt_cb;
222
223 /**
224 * If protocol is NULL, returns the first registered protocol,
225 * if protocol is non-NULL, returns the next registered protocol after protocol,
226 * or NULL if protocol is the last one.
227 */
228 URLProtocol *av_protocol_next(URLProtocol *p);
229
230 #if LIBAVFORMAT_VERSION_MAJOR < 53
231 /**
232 * @deprecated Use av_register_protocol() instead.
233 */
234 attribute_deprecated int register_protocol(URLProtocol *protocol);
235 #endif
236
237 /**
238 * Registers the URLProtocol protocol.
239 */
240 int av_register_protocol(URLProtocol *protocol);
241
242 /**
243 * Bytestream IO Context.
244 * New fields can be added to the end with minor version bumps.
245 * Removal, reordering and changes to existing fields require a major
246 * version bump.
247 * sizeof(ByteIOContext) must not be used outside libav*.
248 */
249 typedef struct {
250 unsigned char *buffer;
251 int buffer_size;
252 unsigned char *buf_ptr, *buf_end;
253 void *opaque;
254 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
255 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
256 int64_t (*seek)(void *opaque, int64_t offset, int whence);
257 int64_t pos; /**< position in the file of the current buffer */
258 int must_flush; /**< true if the next seek should flush */
259 int eof_reached; /**< true if eof reached */
260 int write_flag; /**< true if open for writing */
261 int is_streamed;
262 int max_packet_size;
263 unsigned long checksum;
264 unsigned char *checksum_ptr;
265 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
266 int error; ///< contains the error code or 0 if no error happened
267 int (*read_pause)(void *opaque, int pause);
268 int64_t (*read_seek)(void *opaque, int stream_index,
269 int64_t timestamp, int flags);
270 } ByteIOContext;
271
272 int init_put_byte(ByteIOContext *s,
273 unsigned char *buffer,
274 int buffer_size,
275 int write_flag,
276 void *opaque,
277 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
278 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
279 int64_t (*seek)(void *opaque, int64_t offset, int whence));
280 ByteIOContext *av_alloc_put_byte(
281 unsigned char *buffer,
282 int buffer_size,
283 int write_flag,
284 void *opaque,
285 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
286 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
287 int64_t (*seek)(void *opaque, int64_t offset, int whence));
288
289 void put_byte(ByteIOContext *s, int b);
290 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
291 void put_le64(ByteIOContext *s, uint64_t val);
292 void put_be64(ByteIOContext *s, uint64_t val);
293 void put_le32(ByteIOContext *s, unsigned int val);
294 void put_be32(ByteIOContext *s, unsigned int val);
295 void put_le24(ByteIOContext *s, unsigned int val);
296 void put_be24(ByteIOContext *s, unsigned int val);
297 void put_le16(ByteIOContext *s, unsigned int val);
298 void put_be16(ByteIOContext *s, unsigned int val);
299 void put_tag(ByteIOContext *s, const char *tag);
300
301 void put_strz(ByteIOContext *s, const char *buf);
302
303 /**
304 * fseek() equivalent for ByteIOContext.
305 * @return new position or AVERROR.
306 */
307 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
308
309 /**
310 * Skip given number of bytes forward.
311 * @param offset number of bytes
312 */
313 void url_fskip(ByteIOContext *s, int64_t offset);
314
315 /**
316 * ftell() equivalent for ByteIOContext.
317 * @return position or AVERROR.
318 */
319 int64_t url_ftell(ByteIOContext *s);
320
321 /**
322 * Gets the filesize.
323 * @return filesize or AVERROR
324 */
325 int64_t url_fsize(ByteIOContext *s);
326
327 /**
328 * feof() equivalent for ByteIOContext.
329 * @return non zero if and only if end of file
330 */
331 int url_feof(ByteIOContext *s);
332
333 int url_ferror(ByteIOContext *s);
334
335 int av_url_read_fpause(ByteIOContext *h, int pause);
336 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
337 int64_t timestamp, int flags);
338
339 #define URL_EOF (-1)
340 /** @note return URL_EOF (-1) if EOF */
341 int url_fgetc(ByteIOContext *s);
342
343 /** @warning currently size is limited */
344 #ifdef __GNUC__
345 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
346 #else
347 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
348 #endif
349
350 /** @note unlike fgets, the EOL character is not returned and a whole
351 line is parsed. return NULL if first char read was EOF */
352 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
353
354 void put_flush_packet(ByteIOContext *s);
355
356
357 /**
358 * Reads size bytes from ByteIOContext into buf.
359 * @returns number of bytes read or AVERROR
360 */
361 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
362
363 /**
364 * Reads size bytes from ByteIOContext into buf.
365 * This reads at most 1 packet. If that is not enough fewer bytes will be
366 * returned.
367 * @returns number of bytes read or AVERROR
368 */
369 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
370
371 /** @note return 0 if EOF, so you cannot use it if EOF handling is
372 necessary */
373 int get_byte(ByteIOContext *s);
374 unsigned int get_le24(ByteIOContext *s);
375 unsigned int get_le32(ByteIOContext *s);
376 uint64_t get_le64(ByteIOContext *s);
377 unsigned int get_le16(ByteIOContext *s);
378
379 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
380 unsigned int get_be16(ByteIOContext *s);
381 unsigned int get_be24(ByteIOContext *s);
382 unsigned int get_be32(ByteIOContext *s);
383 uint64_t get_be64(ByteIOContext *s);
384
385 uint64_t ff_get_v(ByteIOContext *bc);
386
387 static inline int url_is_streamed(ByteIOContext *s)
388 {
389 return s->is_streamed;
390 }
391
392 /**
393 * Creates and initializes a ByteIOContext for accessing the
394 * resource referenced by the URLContext h.
395 * @note When the URLContext h has been opened in read+write mode, the
396 * ByteIOContext can be used only for writing.
397 *
398 * @param s Used to return the pointer to the created ByteIOContext.
399 * In case of failure the pointed to value is set to NULL.
400 * @return 0 in case of success, a negative value corresponding to an
401 * AVERROR code in case of failure
402 */
403 int url_fdopen(ByteIOContext **s, URLContext *h);
404
405 /** @warning must be called before any I/O */
406 int url_setbufsize(ByteIOContext *s, int buf_size);
407 #if LIBAVFORMAT_VERSION_MAJOR < 53
408 /** Reset the buffer for reading or writing.
409 * @note Will drop any data currently in the buffer without transmitting it.
410 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
411 * to set up the buffer for writing. */
412 int url_resetbuf(ByteIOContext *s, int flags);
413 #endif
414
415 /**
416 * Creates and initializes a ByteIOContext for accessing the
417 * resource indicated by url.
418 * @note When the resource indicated by url has been opened in
419 * read+write mode, the ByteIOContext can be used only for writing.
420 *
421 * @param s Used to return the pointer to the created ByteIOContext.
422 * In case of failure the pointed to value is set to NULL.
423 * @param flags flags which control how the resource indicated by url
424 * is to be opened
425 * @return 0 in case of success, a negative value corresponding to an
426 * AVERROR code in case of failure
427 */
428 int url_fopen(ByteIOContext **s, const char *url, int flags);
429
430 int url_fclose(ByteIOContext *s);
431 URLContext *url_fileno(ByteIOContext *s);
432
433 /**
434 * Return the maximum packet size associated to packetized buffered file
435 * handle. If the file is not packetized (stream like http or file on
436 * disk), then 0 is returned.
437 *
438 * @param s buffered file handle
439 * @return maximum packet size in bytes
440 */
441 int url_fget_max_packet_size(ByteIOContext *s);
442
443 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
444
445 /** return the written or read size */
446 int url_close_buf(ByteIOContext *s);
447
448 /**
449 * Open a write only memory stream.
450 *
451 * @param s new IO context
452 * @return zero if no error.
453 */
454 int url_open_dyn_buf(ByteIOContext **s);
455
456 /**
457 * Open a write only packetized memory stream with a maximum packet
458 * size of 'max_packet_size'. The stream is stored in a memory buffer
459 * with a big endian 4 byte header giving the packet size in bytes.
460 *
461 * @param s new IO context
462 * @param max_packet_size maximum packet size (must be > 0)
463 * @return zero if no error.
464 */
465 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
466
467 /**
468 * Return the written size and a pointer to the buffer. The buffer
469 * must be freed with av_free().
470 * @param s IO context
471 * @param pbuffer pointer to a byte buffer
472 * @return the length of the byte buffer
473 */
474 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
475
476 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
477 unsigned int len);
478 unsigned long get_checksum(ByteIOContext *s);
479 void init_checksum(ByteIOContext *s,
480 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
481 unsigned long checksum);
482
483 /* udp.c */
484 int udp_set_remote_url(URLContext *h, const char *uri);
485 int udp_get_local_port(URLContext *h);
486 #if (LIBAVFORMAT_VERSION_MAJOR <= 52)
487 int udp_get_file_handle(URLContext *h);
488 #endif
489
490 #endif /* AVFORMAT_AVIO_H */