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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 | |
25 | * @ingroup lavf_io | |
26 | * Buffered I/O operations | |
27 | */ | |
28 | ||
29 | #include <stdint.h> | |
30 | ||
31 | #include "libavutil/common.h" | |
32 | #include "libavutil/dict.h" | |
33 | #include "libavutil/log.h" | |
34 | ||
35 | #include "libavformat/version.h" | |
36 | ||
37 | ||
38 | #define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */ | |
39 | ||
40 | /** | |
41 | * Callback for checking whether to abort blocking functions. | |
42 | * AVERROR_EXIT is returned in this case by the interrupted | |
43 | * function. During blocking operations, callback is called with | |
44 | * opaque as parameter. If the callback returns 1, the | |
45 | * blocking operation will be aborted. | |
46 | * | |
47 | * No members can be added to this struct without a major bump, if | |
48 | * new elements have been added after this struct in AVFormatContext | |
49 | * or AVIOContext. | |
50 | */ | |
51 | typedef struct AVIOInterruptCB { | |
52 | int (*callback)(void*); | |
53 | void *opaque; | |
54 | } AVIOInterruptCB; | |
55 | ||
56 | /** | |
57 | * Bytestream IO Context. | |
58 | * New fields can be added to the end with minor version bumps. | |
59 | * Removal, reordering and changes to existing fields require a major | |
60 | * version bump. | |
61 | * sizeof(AVIOContext) must not be used outside libav*. | |
62 | * | |
63 | * @note None of the function pointers in AVIOContext should be called | |
64 | * directly, they should only be set by the client application | |
65 | * when implementing custom I/O. Normally these are set to the | |
66 | * function pointers specified in avio_alloc_context() | |
67 | */ | |
68 | typedef struct AVIOContext { | |
69 | /** | |
70 | * A class for private options. | |
71 | * | |
72 | * If this AVIOContext is created by avio_open2(), av_class is set and | |
73 | * passes the options down to protocols. | |
74 | * | |
75 | * If this AVIOContext is manually allocated, then av_class may be set by | |
76 | * the caller. | |
77 | * | |
78 | * warning -- this field can be NULL, be sure to not pass this AVIOContext | |
79 | * to any av_opt_* functions in that case. | |
80 | */ | |
81 | const AVClass *av_class; | |
82 | unsigned char *buffer; /**< Start of the buffer. */ | |
83 | int buffer_size; /**< Maximum buffer size */ | |
84 | unsigned char *buf_ptr; /**< Current position in the buffer */ | |
85 | unsigned char *buf_end; /**< End of the data, may be less than | |
86 | buffer+buffer_size if the read function returned | |
87 | less data than requested, e.g. for streams where | |
88 | no more data has been received yet. */ | |
89 | void *opaque; /**< A private pointer, passed to the read/write/seek/... | |
90 | functions. */ | |
91 | int (*read_packet)(void *opaque, uint8_t *buf, int buf_size); | |
92 | int (*write_packet)(void *opaque, uint8_t *buf, int buf_size); | |
93 | int64_t (*seek)(void *opaque, int64_t offset, int whence); | |
94 | int64_t pos; /**< position in the file of the current buffer */ | |
95 | int must_flush; /**< true if the next seek should flush */ | |
96 | int eof_reached; /**< true if eof reached */ | |
97 | int write_flag; /**< true if open for writing */ | |
98 | int max_packet_size; | |
99 | unsigned long checksum; | |
100 | unsigned char *checksum_ptr; | |
101 | unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size); | |
102 | int error; /**< contains the error code or 0 if no error happened */ | |
103 | /** | |
104 | * Pause or resume playback for network streaming protocols - e.g. MMS. | |
105 | */ | |
106 | int (*read_pause)(void *opaque, int pause); | |
107 | /** | |
108 | * Seek to a given timestamp in stream with the specified stream_index. | |
109 | * Needed for some network streaming protocols which don't support seeking | |
110 | * to byte position. | |
111 | */ | |
112 | int64_t (*read_seek)(void *opaque, int stream_index, | |
113 | int64_t timestamp, int flags); | |
114 | /** | |
115 | * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable. | |
116 | */ | |
117 | int seekable; | |
118 | ||
119 | /** | |
120 | * max filesize, used to limit allocations | |
121 | * This field is internal to libavformat and access from outside is not allowed. | |
122 | */ | |
123 | int64_t maxsize; | |
124 | ||
125 | /** | |
126 | * avio_read and avio_write should if possible be satisfied directly | |
127 | * instead of going through a buffer, and avio_seek will always | |
128 | * call the underlying seek function directly. | |
129 | */ | |
130 | int direct; | |
131 | ||
132 | /** | |
133 | * Bytes read statistic | |
134 | * This field is internal to libavformat and access from outside is not allowed. | |
135 | */ | |
136 | int64_t bytes_read; | |
137 | ||
138 | /** | |
139 | * seek statistic | |
140 | * This field is internal to libavformat and access from outside is not allowed. | |
141 | */ | |
142 | int seek_count; | |
143 | ||
144 | /** | |
145 | * writeout statistic | |
146 | * This field is internal to libavformat and access from outside is not allowed. | |
147 | */ | |
148 | int writeout_count; | |
149 | ||
150 | /** | |
151 | * Original buffer size | |
152 | * used internally after probing and ensure seekback to reset the buffer size | |
153 | * This field is internal to libavformat and access from outside is not allowed. | |
154 | */ | |
155 | int orig_buffer_size; | |
156 | } AVIOContext; | |
157 | ||
158 | /* unbuffered I/O */ | |
159 | ||
160 | /** | |
161 | * Return the name of the protocol that will handle the passed URL. | |
162 | * | |
163 | * NULL is returned if no protocol could be found for the given URL. | |
164 | * | |
165 | * @return Name of the protocol or NULL. | |
166 | */ | |
167 | const char *avio_find_protocol_name(const char *url); | |
168 | ||
169 | /** | |
170 | * Return AVIO_FLAG_* access flags corresponding to the access permissions | |
171 | * of the resource in url, or a negative value corresponding to an | |
172 | * AVERROR code in case of failure. The returned access flags are | |
173 | * masked by the value in flags. | |
174 | * | |
175 | * @note This function is intrinsically unsafe, in the sense that the | |
176 | * checked resource may change its existence or permission status from | |
177 | * one call to another. Thus you should not trust the returned value, | |
178 | * unless you are sure that no other processes are accessing the | |
179 | * checked resource. | |
180 | */ | |
181 | int avio_check(const char *url, int flags); | |
182 | ||
183 | /** | |
184 | * Allocate and initialize an AVIOContext for buffered I/O. It must be later | |
185 | * freed with av_free(). | |
186 | * | |
187 | * @param buffer Memory block for input/output operations via AVIOContext. | |
188 | * The buffer must be allocated with av_malloc() and friends. | |
f6fa7814 DM |
189 | * It may be freed and replaced with a new buffer by libavformat. |
190 | * AVIOContext.buffer holds the buffer currently in use, | |
191 | * which must be later freed with av_free(). | |
2ba45a60 DM |
192 | * @param buffer_size The buffer size is very important for performance. |
193 | * For protocols with fixed blocksize it should be set to this blocksize. | |
194 | * For others a typical size is a cache page, e.g. 4kb. | |
195 | * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise. | |
196 | * @param opaque An opaque pointer to user-specific data. | |
197 | * @param read_packet A function for refilling the buffer, may be NULL. | |
198 | * @param write_packet A function for writing the buffer contents, may be NULL. | |
199 | * The function may not change the input buffers content. | |
200 | * @param seek A function for seeking to specified byte position, may be NULL. | |
201 | * | |
202 | * @return Allocated AVIOContext or NULL on failure. | |
203 | */ | |
204 | AVIOContext *avio_alloc_context( | |
205 | unsigned char *buffer, | |
206 | int buffer_size, | |
207 | int write_flag, | |
208 | void *opaque, | |
209 | int (*read_packet)(void *opaque, uint8_t *buf, int buf_size), | |
210 | int (*write_packet)(void *opaque, uint8_t *buf, int buf_size), | |
211 | int64_t (*seek)(void *opaque, int64_t offset, int whence)); | |
212 | ||
213 | void avio_w8(AVIOContext *s, int b); | |
214 | void avio_write(AVIOContext *s, const unsigned char *buf, int size); | |
215 | void avio_wl64(AVIOContext *s, uint64_t val); | |
216 | void avio_wb64(AVIOContext *s, uint64_t val); | |
217 | void avio_wl32(AVIOContext *s, unsigned int val); | |
218 | void avio_wb32(AVIOContext *s, unsigned int val); | |
219 | void avio_wl24(AVIOContext *s, unsigned int val); | |
220 | void avio_wb24(AVIOContext *s, unsigned int val); | |
221 | void avio_wl16(AVIOContext *s, unsigned int val); | |
222 | void avio_wb16(AVIOContext *s, unsigned int val); | |
223 | ||
224 | /** | |
225 | * Write a NULL-terminated string. | |
226 | * @return number of bytes written. | |
227 | */ | |
228 | int avio_put_str(AVIOContext *s, const char *str); | |
229 | ||
230 | /** | |
231 | * Convert an UTF-8 string to UTF-16LE and write it. | |
232 | * @return number of bytes written. | |
233 | */ | |
234 | int avio_put_str16le(AVIOContext *s, const char *str); | |
235 | ||
236 | /** | |
237 | * Passing this as the "whence" parameter to a seek function causes it to | |
238 | * return the filesize without seeking anywhere. Supporting this is optional. | |
239 | * If it is not supported then the seek function will return <0. | |
240 | */ | |
241 | #define AVSEEK_SIZE 0x10000 | |
242 | ||
243 | /** | |
244 | * Oring this flag as into the "whence" parameter to a seek function causes it to | |
245 | * seek by any means (like reopening and linear reading) or other normally unreasonable | |
246 | * means that can be extremely slow. | |
247 | * This may be ignored by the seek code. | |
248 | */ | |
249 | #define AVSEEK_FORCE 0x20000 | |
250 | ||
251 | /** | |
252 | * fseek() equivalent for AVIOContext. | |
253 | * @return new position or AVERROR. | |
254 | */ | |
255 | int64_t avio_seek(AVIOContext *s, int64_t offset, int whence); | |
256 | ||
257 | /** | |
258 | * Skip given number of bytes forward | |
259 | * @return new position or AVERROR. | |
260 | */ | |
261 | int64_t avio_skip(AVIOContext *s, int64_t offset); | |
262 | ||
263 | /** | |
264 | * ftell() equivalent for AVIOContext. | |
265 | * @return position or AVERROR. | |
266 | */ | |
267 | static av_always_inline int64_t avio_tell(AVIOContext *s) | |
268 | { | |
269 | return avio_seek(s, 0, SEEK_CUR); | |
270 | } | |
271 | ||
272 | /** | |
273 | * Get the filesize. | |
274 | * @return filesize or AVERROR | |
275 | */ | |
276 | int64_t avio_size(AVIOContext *s); | |
277 | ||
278 | /** | |
279 | * feof() equivalent for AVIOContext. | |
280 | * @return non zero if and only if end of file | |
281 | */ | |
282 | int avio_feof(AVIOContext *s); | |
283 | #if FF_API_URL_FEOF | |
284 | /** | |
285 | * @deprecated use avio_feof() | |
286 | */ | |
287 | attribute_deprecated | |
288 | int url_feof(AVIOContext *s); | |
289 | #endif | |
290 | ||
291 | /** @warning currently size is limited */ | |
292 | int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3); | |
293 | ||
294 | /** | |
f6fa7814 | 295 | * Force flushing of buffered data. |
2ba45a60 | 296 | * |
f6fa7814 | 297 | * For write streams, force the buffered data to be immediately written to the output, |
2ba45a60 | 298 | * without to wait to fill the internal buffer. |
f6fa7814 DM |
299 | * |
300 | * For read streams, discard all currently buffered data, and advance the | |
301 | * reported file position to that of the underlying stream. This does not | |
302 | * read new data, and does not perform any seeks. | |
2ba45a60 DM |
303 | */ |
304 | void avio_flush(AVIOContext *s); | |
305 | ||
306 | /** | |
307 | * Read size bytes from AVIOContext into buf. | |
308 | * @return number of bytes read or AVERROR | |
309 | */ | |
310 | int avio_read(AVIOContext *s, unsigned char *buf, int size); | |
311 | ||
312 | /** | |
313 | * @name Functions for reading from AVIOContext | |
314 | * @{ | |
315 | * | |
316 | * @note return 0 if EOF, so you cannot use it if EOF handling is | |
317 | * necessary | |
318 | */ | |
319 | int avio_r8 (AVIOContext *s); | |
320 | unsigned int avio_rl16(AVIOContext *s); | |
321 | unsigned int avio_rl24(AVIOContext *s); | |
322 | unsigned int avio_rl32(AVIOContext *s); | |
323 | uint64_t avio_rl64(AVIOContext *s); | |
324 | unsigned int avio_rb16(AVIOContext *s); | |
325 | unsigned int avio_rb24(AVIOContext *s); | |
326 | unsigned int avio_rb32(AVIOContext *s); | |
327 | uint64_t avio_rb64(AVIOContext *s); | |
328 | /** | |
329 | * @} | |
330 | */ | |
331 | ||
332 | /** | |
333 | * Read a string from pb into buf. The reading will terminate when either | |
334 | * a NULL character was encountered, maxlen bytes have been read, or nothing | |
335 | * more can be read from pb. The result is guaranteed to be NULL-terminated, it | |
336 | * will be truncated if buf is too small. | |
337 | * Note that the string is not interpreted or validated in any way, it | |
338 | * might get truncated in the middle of a sequence for multi-byte encodings. | |
339 | * | |
340 | * @return number of bytes read (is always <= maxlen). | |
341 | * If reading ends on EOF or error, the return value will be one more than | |
342 | * bytes actually read. | |
343 | */ | |
344 | int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen); | |
345 | ||
346 | /** | |
347 | * Read a UTF-16 string from pb and convert it to UTF-8. | |
348 | * The reading will terminate when either a null or invalid character was | |
349 | * encountered or maxlen bytes have been read. | |
350 | * @return number of bytes read (is always <= maxlen) | |
351 | */ | |
352 | int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen); | |
353 | int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen); | |
354 | ||
355 | ||
356 | /** | |
357 | * @name URL open modes | |
358 | * The flags argument to avio_open must be one of the following | |
359 | * constants, optionally ORed with other flags. | |
360 | * @{ | |
361 | */ | |
362 | #define AVIO_FLAG_READ 1 /**< read-only */ | |
363 | #define AVIO_FLAG_WRITE 2 /**< write-only */ | |
364 | #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */ | |
365 | /** | |
366 | * @} | |
367 | */ | |
368 | ||
369 | /** | |
370 | * Use non-blocking mode. | |
371 | * If this flag is set, operations on the context will return | |
372 | * AVERROR(EAGAIN) if they can not be performed immediately. | |
373 | * If this flag is not set, operations on the context will never return | |
374 | * AVERROR(EAGAIN). | |
375 | * Note that this flag does not affect the opening/connecting of the | |
376 | * context. Connecting a protocol will always block if necessary (e.g. on | |
377 | * network protocols) but never hang (e.g. on busy devices). | |
378 | * Warning: non-blocking protocols is work-in-progress; this flag may be | |
379 | * silently ignored. | |
380 | */ | |
381 | #define AVIO_FLAG_NONBLOCK 8 | |
382 | ||
383 | /** | |
384 | * Use direct mode. | |
385 | * avio_read and avio_write should if possible be satisfied directly | |
386 | * instead of going through a buffer, and avio_seek will always | |
387 | * call the underlying seek function directly. | |
388 | */ | |
389 | #define AVIO_FLAG_DIRECT 0x8000 | |
390 | ||
391 | /** | |
392 | * Create and initialize a AVIOContext for accessing the | |
393 | * resource indicated by url. | |
394 | * @note When the resource indicated by url has been opened in | |
395 | * read+write mode, the AVIOContext can be used only for writing. | |
396 | * | |
397 | * @param s Used to return the pointer to the created AVIOContext. | |
398 | * In case of failure the pointed to value is set to NULL. | |
399 | * @param url resource to access | |
400 | * @param flags flags which control how the resource indicated by url | |
401 | * is to be opened | |
402 | * @return >= 0 in case of success, a negative value corresponding to an | |
403 | * AVERROR code in case of failure | |
404 | */ | |
405 | int avio_open(AVIOContext **s, const char *url, int flags); | |
406 | ||
407 | /** | |
408 | * Create and initialize a AVIOContext for accessing the | |
409 | * resource indicated by url. | |
410 | * @note When the resource indicated by url has been opened in | |
411 | * read+write mode, the AVIOContext can be used only for writing. | |
412 | * | |
413 | * @param s Used to return the pointer to the created AVIOContext. | |
414 | * In case of failure the pointed to value is set to NULL. | |
415 | * @param url resource to access | |
416 | * @param flags flags which control how the resource indicated by url | |
417 | * is to be opened | |
418 | * @param int_cb an interrupt callback to be used at the protocols level | |
419 | * @param options A dictionary filled with protocol-private options. On return | |
420 | * this parameter will be destroyed and replaced with a dict containing options | |
421 | * that were not found. May be NULL. | |
422 | * @return >= 0 in case of success, a negative value corresponding to an | |
423 | * AVERROR code in case of failure | |
424 | */ | |
425 | int avio_open2(AVIOContext **s, const char *url, int flags, | |
426 | const AVIOInterruptCB *int_cb, AVDictionary **options); | |
427 | ||
428 | /** | |
429 | * Close the resource accessed by the AVIOContext s and free it. | |
430 | * This function can only be used if s was opened by avio_open(). | |
431 | * | |
432 | * The internal buffer is automatically flushed before closing the | |
433 | * resource. | |
434 | * | |
435 | * @return 0 on success, an AVERROR < 0 on error. | |
436 | * @see avio_closep | |
437 | */ | |
438 | int avio_close(AVIOContext *s); | |
439 | ||
440 | /** | |
441 | * Close the resource accessed by the AVIOContext *s, free it | |
442 | * and set the pointer pointing to it to NULL. | |
443 | * This function can only be used if s was opened by avio_open(). | |
444 | * | |
445 | * The internal buffer is automatically flushed before closing the | |
446 | * resource. | |
447 | * | |
448 | * @return 0 on success, an AVERROR < 0 on error. | |
449 | * @see avio_close | |
450 | */ | |
451 | int avio_closep(AVIOContext **s); | |
452 | ||
453 | ||
454 | /** | |
455 | * Open a write only memory stream. | |
456 | * | |
457 | * @param s new IO context | |
458 | * @return zero if no error. | |
459 | */ | |
460 | int avio_open_dyn_buf(AVIOContext **s); | |
461 | ||
462 | /** | |
463 | * Return the written size and a pointer to the buffer. The buffer | |
464 | * must be freed with av_free(). | |
465 | * Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer. | |
466 | * | |
467 | * @param s IO context | |
468 | * @param pbuffer pointer to a byte buffer | |
469 | * @return the length of the byte buffer | |
470 | */ | |
471 | int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer); | |
472 | ||
473 | /** | |
474 | * Iterate through names of available protocols. | |
475 | * | |
476 | * @param opaque A private pointer representing current protocol. | |
477 | * It must be a pointer to NULL on first iteration and will | |
478 | * be updated by successive calls to avio_enum_protocols. | |
479 | * @param output If set to 1, iterate over output protocols, | |
480 | * otherwise over input protocols. | |
481 | * | |
482 | * @return A static string containing the name of current protocol or NULL | |
483 | */ | |
484 | const char *avio_enum_protocols(void **opaque, int output); | |
485 | ||
486 | /** | |
487 | * Pause and resume playing - only meaningful if using a network streaming | |
488 | * protocol (e.g. MMS). | |
489 | * | |
490 | * @param h IO context from which to call the read_pause function pointer | |
491 | * @param pause 1 for pause, 0 for resume | |
492 | */ | |
493 | int avio_pause(AVIOContext *h, int pause); | |
494 | ||
495 | /** | |
496 | * Seek to a given timestamp relative to some component stream. | |
497 | * Only meaningful if using a network streaming protocol (e.g. MMS.). | |
498 | * | |
499 | * @param h IO context from which to call the seek function pointers | |
500 | * @param stream_index The stream index that the timestamp is relative to. | |
501 | * If stream_index is (-1) the timestamp should be in AV_TIME_BASE | |
502 | * units from the beginning of the presentation. | |
503 | * If a stream_index >= 0 is used and the protocol does not support | |
504 | * seeking based on component streams, the call will fail. | |
505 | * @param timestamp timestamp in AVStream.time_base units | |
506 | * or if there is no stream specified then in AV_TIME_BASE units. | |
507 | * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE | |
508 | * and AVSEEK_FLAG_ANY. The protocol may silently ignore | |
509 | * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will | |
510 | * fail if used and not supported. | |
511 | * @return >= 0 on success | |
512 | * @see AVInputFormat::read_seek | |
513 | */ | |
514 | int64_t avio_seek_time(AVIOContext *h, int stream_index, | |
515 | int64_t timestamp, int flags); | |
516 | ||
517 | /* Avoid a warning. The header can not be included because it breaks c++. */ | |
518 | struct AVBPrint; | |
519 | ||
520 | /** | |
521 | * Read contents of h into print buffer, up to max_size bytes, or up to EOF. | |
522 | * | |
523 | * @return 0 for success (max_size bytes read or EOF reached), negative error | |
524 | * code otherwise | |
525 | */ | |
526 | int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size); | |
527 | ||
528 | #endif /* AVFORMAT_AVIO_H */ |