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avio.h
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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  * Seeking works like for a local file.
39  */
40 #define AVIO_SEEKABLE_NORMAL (1 << 0)
41 
42 /**
43  * Seeking by timestamp with avio_seek_time() is possible.
44  */
45 #define AVIO_SEEKABLE_TIME (1 << 1)
46 
47 /**
48  * Callback for checking whether to abort blocking functions.
49  * AVERROR_EXIT is returned in this case by the interrupted
50  * function. During blocking operations, callback is called with
51  * opaque as parameter. If the callback returns 1, the
52  * blocking operation will be aborted.
53  *
54  * No members can be added to this struct without a major bump, if
55  * new elements have been added after this struct in AVFormatContext
56  * or AVIOContext.
57  */
58 typedef struct AVIOInterruptCB {
59  int (*callback)(void*);
60  void *opaque;
62 
63 /**
64  * Directory entry types.
65  */
78 };
79 
80 /**
81  * Describes single entry of the directory.
82  *
83  * Only name and type fields are guaranteed be set.
84  * Rest of fields are protocol or/and platform dependent and might be unknown.
85  */
86 typedef struct AVIODirEntry {
87  char *name; /**< Filename */
88  int type; /**< Type of the entry */
89  int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise.
90  Name can be encoded with UTF-8 even though 0 is set. */
91  int64_t size; /**< File size in bytes, -1 if unknown. */
92  int64_t modification_timestamp; /**< Time of last modification in microseconds since unix
93  epoch, -1 if unknown. */
94  int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch,
95  -1 if unknown. */
96  int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix
97  epoch, -1 if unknown. */
98  int64_t user_id; /**< User ID of owner, -1 if unknown. */
99  int64_t group_id; /**< Group ID of owner, -1 if unknown. */
100  int64_t filemode; /**< Unix file mode, -1 if unknown. */
101 } AVIODirEntry;
102 
103 typedef struct AVIODirContext {
106 
107 /**
108  * Different data types that can be returned via the AVIO
109  * write_data_type callback.
110  */
112  /**
113  * Header data; this needs to be present for the stream to be decodeable.
114  */
116  /**
117  * A point in the output bytestream where a decoder can start decoding
118  * (i.e. a keyframe). A demuxer/decoder given the data flagged with
119  * AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT,
120  * should give decodeable results.
121  */
123  /**
124  * A point in the output bytestream where a demuxer can start parsing
125  * (for non self synchronizing bytestream formats). That is, any
126  * non-keyframe packet start point.
127  */
129  /**
130  * This is any, unlabelled data. It can either be a muxer not marking
131  * any positions at all, it can be an actual boundary/sync point
132  * that the muxer chooses not to mark, or a later part of a packet/fragment
133  * that is cut into multiple write callbacks due to limited IO buffer size.
134  */
136  /**
137  * Trailer data, which doesn't contain actual content, but only for
138  * finalizing the output file.
139  */
141 };
142 
143 /**
144  * Bytestream IO Context.
145  * New fields can be added to the end with minor version bumps.
146  * Removal, reordering and changes to existing fields require a major
147  * version bump.
148  * sizeof(AVIOContext) must not be used outside libav*.
149  *
150  * @note None of the function pointers in AVIOContext should be called
151  * directly, they should only be set by the client application
152  * when implementing custom I/O. Normally these are set to the
153  * function pointers specified in avio_alloc_context()
154  */
155 typedef struct AVIOContext {
156  /**
157  * A class for private options.
158  *
159  * If this AVIOContext is created by avio_open2(), av_class is set and
160  * passes the options down to protocols.
161  *
162  * If this AVIOContext is manually allocated, then av_class may be set by
163  * the caller.
164  *
165  * warning -- this field can be NULL, be sure to not pass this AVIOContext
166  * to any av_opt_* functions in that case.
167  */
169 
170  /*
171  * The following shows the relationship between buffer, buf_ptr, buf_end, buf_size,
172  * and pos, when reading and when writing (since AVIOContext is used for both):
173  *
174  **********************************************************************************
175  * READING
176  **********************************************************************************
177  *
178  * | buffer_size |
179  * |---------------------------------------|
180  * | |
181  *
182  * buffer buf_ptr buf_end
183  * +---------------+-----------------------+
184  * |/ / / / / / / /|/ / / / / / /| |
185  * read buffer: |/ / consumed / | to be read /| |
186  * |/ / / / / / / /|/ / / / / / /| |
187  * +---------------+-----------------------+
188  *
189  * pos
190  * +-------------------------------------------+-----------------+
191  * input file: | | |
192  * +-------------------------------------------+-----------------+
193  *
194  *
195  **********************************************************************************
196  * WRITING
197  **********************************************************************************
198  *
199  * | buffer_size |
200  * |-------------------------------|
201  * | |
202  *
203  * buffer buf_ptr buf_end
204  * +-------------------+-----------+
205  * |/ / / / / / / / / /| |
206  * write buffer: | / to be flushed / | |
207  * |/ / / / / / / / / /| |
208  * +-------------------+-----------+
209  *
210  * pos
211  * +--------------------------+-----------------------------------+
212  * output file: | | |
213  * +--------------------------+-----------------------------------+
214  *
215  */
216  unsigned char *buffer; /**< Start of the buffer. */
217  int buffer_size; /**< Maximum buffer size */
218  unsigned char *buf_ptr; /**< Current position in the buffer */
219  unsigned char *buf_end; /**< End of the data, may be less than
220  buffer+buffer_size if the read function returned
221  less data than requested, e.g. for streams where
222  no more data has been received yet. */
223  void *opaque; /**< A private pointer, passed to the read/write/seek/...
224  functions. */
225  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
226  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
227  int64_t (*seek)(void *opaque, int64_t offset, int whence);
228  int64_t pos; /**< position in the file of the current buffer */
229  int must_flush; /**< true if the next seek should flush */
230  int eof_reached; /**< true if eof reached */
231  int write_flag; /**< true if open for writing */
233  unsigned long checksum;
234  unsigned char *checksum_ptr;
235  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
236  int error; /**< contains the error code or 0 if no error happened */
237  /**
238  * Pause or resume playback for network streaming protocols - e.g. MMS.
239  */
240  int (*read_pause)(void *opaque, int pause);
241  /**
242  * Seek to a given timestamp in stream with the specified stream_index.
243  * Needed for some network streaming protocols which don't support seeking
244  * to byte position.
245  */
246  int64_t (*read_seek)(void *opaque, int stream_index,
247  int64_t timestamp, int flags);
248  /**
249  * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
250  */
251  int seekable;
252 
253  /**
254  * max filesize, used to limit allocations
255  * This field is internal to libavformat and access from outside is not allowed.
256  */
257  int64_t maxsize;
258 
259  /**
260  * avio_read and avio_write should if possible be satisfied directly
261  * instead of going through a buffer, and avio_seek will always
262  * call the underlying seek function directly.
263  */
264  int direct;
265 
266  /**
267  * Bytes read statistic
268  * This field is internal to libavformat and access from outside is not allowed.
269  */
270  int64_t bytes_read;
271 
272  /**
273  * seek statistic
274  * This field is internal to libavformat and access from outside is not allowed.
275  */
277 
278  /**
279  * writeout statistic
280  * This field is internal to libavformat and access from outside is not allowed.
281  */
283 
284  /**
285  * Original buffer size
286  * used internally after probing and ensure seekback to reset the buffer size
287  * This field is internal to libavformat and access from outside is not allowed.
288  */
290 
291  /**
292  * Threshold to favor readahead over seek.
293  * This is current internal only, do not use from outside.
294  */
296 
297  /**
298  * ',' separated list of allowed protocols.
299  */
300  const char *protocol_whitelist;
301 
302  /**
303  * ',' separated list of disallowed protocols.
304  */
305  const char *protocol_blacklist;
306 
307  /**
308  * A callback that is used instead of write_packet.
309  */
310  int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size,
311  enum AVIODataMarkerType type, int64_t time);
312  /**
313  * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
314  * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
315  * small chunks of data returned from the callback).
316  */
318 
319  /**
320  * Internal, not meant to be used from outside of AVIOContext.
321  */
323  int64_t last_time;
324 
325  /**
326  * A callback that is used instead of short_seek_threshold.
327  * This is current internal only, do not use from outside.
328  */
330 } AVIOContext;
331 
332 /**
333  * Return the name of the protocol that will handle the passed URL.
334  *
335  * NULL is returned if no protocol could be found for the given URL.
336  *
337  * @return Name of the protocol or NULL.
338  */
339 const char *avio_find_protocol_name(const char *url);
340 
341 /**
342  * Return AVIO_FLAG_* access flags corresponding to the access permissions
343  * of the resource in url, or a negative value corresponding to an
344  * AVERROR code in case of failure. The returned access flags are
345  * masked by the value in flags.
346  *
347  * @note This function is intrinsically unsafe, in the sense that the
348  * checked resource may change its existence or permission status from
349  * one call to another. Thus you should not trust the returned value,
350  * unless you are sure that no other processes are accessing the
351  * checked resource.
352  */
353 int avio_check(const char *url, int flags);
354 
355 /**
356  * Move or rename a resource.
357  *
358  * @note url_src and url_dst should share the same protocol and authority.
359  *
360  * @param url_src url to resource to be moved
361  * @param url_dst new url to resource if the operation succeeded
362  * @return >=0 on success or negative on error.
363  */
364 int avpriv_io_move(const char *url_src, const char *url_dst);
365 
366 /**
367  * Delete a resource.
368  *
369  * @param url resource to be deleted.
370  * @return >=0 on success or negative on error.
371  */
372 int avpriv_io_delete(const char *url);
373 
374 /**
375  * Open directory for reading.
376  *
377  * @param s directory read context. Pointer to a NULL pointer must be passed.
378  * @param url directory to be listed.
379  * @param options A dictionary filled with protocol-private options. On return
380  * this parameter will be destroyed and replaced with a dictionary
381  * containing options that were not found. May be NULL.
382  * @return >=0 on success or negative on error.
383  */
384 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
385 
386 /**
387  * Get next directory entry.
388  *
389  * Returned entry must be freed with avio_free_directory_entry(). In particular
390  * it may outlive AVIODirContext.
391  *
392  * @param s directory read context.
393  * @param[out] next next entry or NULL when no more entries.
394  * @return >=0 on success or negative on error. End of list is not considered an
395  * error.
396  */
398 
399 /**
400  * Close directory.
401  *
402  * @note Entries created using avio_read_dir() are not deleted and must be
403  * freeded with avio_free_directory_entry().
404  *
405  * @param s directory read context.
406  * @return >=0 on success or negative on error.
407  */
409 
410 /**
411  * Free entry allocated by avio_read_dir().
412  *
413  * @param entry entry to be freed.
414  */
416 
417 /**
418  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
419  * freed with av_free().
420  *
421  * @param buffer Memory block for input/output operations via AVIOContext.
422  * The buffer must be allocated with av_malloc() and friends.
423  * It may be freed and replaced with a new buffer by libavformat.
424  * AVIOContext.buffer holds the buffer currently in use,
425  * which must be later freed with av_free().
426  * @param buffer_size The buffer size is very important for performance.
427  * For protocols with fixed blocksize it should be set to this blocksize.
428  * For others a typical size is a cache page, e.g. 4kb.
429  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
430  * @param opaque An opaque pointer to user-specific data.
431  * @param read_packet A function for refilling the buffer, may be NULL.
432  * @param write_packet A function for writing the buffer contents, may be NULL.
433  * The function may not change the input buffers content.
434  * @param seek A function for seeking to specified byte position, may be NULL.
435  *
436  * @return Allocated AVIOContext or NULL on failure.
437  */
439  unsigned char *buffer,
440  int buffer_size,
441  int write_flag,
442  void *opaque,
443  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
444  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
445  int64_t (*seek)(void *opaque, int64_t offset, int whence));
446 
447 void avio_w8(AVIOContext *s, int b);
448 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
449 void avio_wl64(AVIOContext *s, uint64_t val);
450 void avio_wb64(AVIOContext *s, uint64_t val);
451 void avio_wl32(AVIOContext *s, unsigned int val);
452 void avio_wb32(AVIOContext *s, unsigned int val);
453 void avio_wl24(AVIOContext *s, unsigned int val);
454 void avio_wb24(AVIOContext *s, unsigned int val);
455 void avio_wl16(AVIOContext *s, unsigned int val);
456 void avio_wb16(AVIOContext *s, unsigned int val);
457 
458 /**
459  * Write a NULL-terminated string.
460  * @return number of bytes written.
461  */
462 int avio_put_str(AVIOContext *s, const char *str);
463 
464 /**
465  * Convert an UTF-8 string to UTF-16LE and write it.
466  * @param s the AVIOContext
467  * @param str NULL-terminated UTF-8 string
468  *
469  * @return number of bytes written.
470  */
471 int avio_put_str16le(AVIOContext *s, const char *str);
472 
473 /**
474  * Convert an UTF-8 string to UTF-16BE and write it.
475  * @param s the AVIOContext
476  * @param str NULL-terminated UTF-8 string
477  *
478  * @return number of bytes written.
479  */
480 int avio_put_str16be(AVIOContext *s, const char *str);
481 
482 /**
483  * Mark the written bytestream as a specific type.
484  *
485  * Zero-length ranges are omitted from the output.
486  *
487  * @param time the stream time the current bytestream pos corresponds to
488  * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
489  * applicable
490  * @param type the kind of data written starting at the current pos
491  */
492 void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
493 
494 /**
495  * ORing this as the "whence" parameter to a seek function causes it to
496  * return the filesize without seeking anywhere. Supporting this is optional.
497  * If it is not supported then the seek function will return <0.
498  */
499 #define AVSEEK_SIZE 0x10000
500 
501 /**
502  * Passing this flag as the "whence" parameter to a seek function causes it to
503  * seek by any means (like reopening and linear reading) or other normally unreasonable
504  * means that can be extremely slow.
505  * This may be ignored by the seek code.
506  */
507 #define AVSEEK_FORCE 0x20000
508 
509 /**
510  * fseek() equivalent for AVIOContext.
511  * @return new position or AVERROR.
512  */
513 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
514 
515 /**
516  * Skip given number of bytes forward
517  * @return new position or AVERROR.
518  */
519 int64_t avio_skip(AVIOContext *s, int64_t offset);
520 
521 /**
522  * ftell() equivalent for AVIOContext.
523  * @return position or AVERROR.
524  */
526 {
527  return avio_seek(s, 0, SEEK_CUR);
528 }
529 
530 /**
531  * Get the filesize.
532  * @return filesize or AVERROR
533  */
534 int64_t avio_size(AVIOContext *s);
535 
536 /**
537  * feof() equivalent for AVIOContext.
538  * @return non zero if and only if end of file
539  */
540 int avio_feof(AVIOContext *s);
541 #if FF_API_URL_FEOF
542 /**
543  * @deprecated use avio_feof()
544  */
546 int url_feof(AVIOContext *s);
547 #endif
548 
549 /** @warning Writes up to 4 KiB per call */
550 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
551 
552 /**
553  * Force flushing of buffered data.
554  *
555  * For write streams, force the buffered data to be immediately written to the output,
556  * without to wait to fill the internal buffer.
557  *
558  * For read streams, discard all currently buffered data, and advance the
559  * reported file position to that of the underlying stream. This does not
560  * read new data, and does not perform any seeks.
561  */
562 void avio_flush(AVIOContext *s);
563 
564 /**
565  * Read size bytes from AVIOContext into buf.
566  * @return number of bytes read or AVERROR
567  */
568 int avio_read(AVIOContext *s, unsigned char *buf, int size);
569 
570 /**
571  * @name Functions for reading from AVIOContext
572  * @{
573  *
574  * @note return 0 if EOF, so you cannot use it if EOF handling is
575  * necessary
576  */
577 int avio_r8 (AVIOContext *s);
578 unsigned int avio_rl16(AVIOContext *s);
579 unsigned int avio_rl24(AVIOContext *s);
580 unsigned int avio_rl32(AVIOContext *s);
581 uint64_t avio_rl64(AVIOContext *s);
582 unsigned int avio_rb16(AVIOContext *s);
583 unsigned int avio_rb24(AVIOContext *s);
584 unsigned int avio_rb32(AVIOContext *s);
585 uint64_t avio_rb64(AVIOContext *s);
586 /**
587  * @}
588  */
589 
590 /**
591  * Read a string from pb into buf. The reading will terminate when either
592  * a NULL character was encountered, maxlen bytes have been read, or nothing
593  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
594  * will be truncated if buf is too small.
595  * Note that the string is not interpreted or validated in any way, it
596  * might get truncated in the middle of a sequence for multi-byte encodings.
597  *
598  * @return number of bytes read (is always <= maxlen).
599  * If reading ends on EOF or error, the return value will be one more than
600  * bytes actually read.
601  */
602 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
603 
604 /**
605  * Read a UTF-16 string from pb and convert it to UTF-8.
606  * The reading will terminate when either a null or invalid character was
607  * encountered or maxlen bytes have been read.
608  * @return number of bytes read (is always <= maxlen)
609  */
610 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
611 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
612 
613 
614 /**
615  * @name URL open modes
616  * The flags argument to avio_open must be one of the following
617  * constants, optionally ORed with other flags.
618  * @{
619  */
620 #define AVIO_FLAG_READ 1 /**< read-only */
621 #define AVIO_FLAG_WRITE 2 /**< write-only */
622 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
623 /**
624  * @}
625  */
626 
627 /**
628  * Use non-blocking mode.
629  * If this flag is set, operations on the context will return
630  * AVERROR(EAGAIN) if they can not be performed immediately.
631  * If this flag is not set, operations on the context will never return
632  * AVERROR(EAGAIN).
633  * Note that this flag does not affect the opening/connecting of the
634  * context. Connecting a protocol will always block if necessary (e.g. on
635  * network protocols) but never hang (e.g. on busy devices).
636  * Warning: non-blocking protocols is work-in-progress; this flag may be
637  * silently ignored.
638  */
639 #define AVIO_FLAG_NONBLOCK 8
640 
641 /**
642  * Use direct mode.
643  * avio_read and avio_write should if possible be satisfied directly
644  * instead of going through a buffer, and avio_seek will always
645  * call the underlying seek function directly.
646  */
647 #define AVIO_FLAG_DIRECT 0x8000
648 
649 /**
650  * Create and initialize a AVIOContext for accessing the
651  * resource indicated by url.
652  * @note When the resource indicated by url has been opened in
653  * read+write mode, the AVIOContext can be used only for writing.
654  *
655  * @param s Used to return the pointer to the created AVIOContext.
656  * In case of failure the pointed to value is set to NULL.
657  * @param url resource to access
658  * @param flags flags which control how the resource indicated by url
659  * is to be opened
660  * @return >= 0 in case of success, a negative value corresponding to an
661  * AVERROR code in case of failure
662  */
663 int avio_open(AVIOContext **s, const char *url, int flags);
664 
665 /**
666  * Create and initialize a AVIOContext for accessing the
667  * resource indicated by url.
668  * @note When the resource indicated by url has been opened in
669  * read+write mode, the AVIOContext can be used only for writing.
670  *
671  * @param s Used to return the pointer to the created AVIOContext.
672  * In case of failure the pointed to value is set to NULL.
673  * @param url resource to access
674  * @param flags flags which control how the resource indicated by url
675  * is to be opened
676  * @param int_cb an interrupt callback to be used at the protocols level
677  * @param options A dictionary filled with protocol-private options. On return
678  * this parameter will be destroyed and replaced with a dict containing options
679  * that were not found. May be NULL.
680  * @return >= 0 in case of success, a negative value corresponding to an
681  * AVERROR code in case of failure
682  */
683 int avio_open2(AVIOContext **s, const char *url, int flags,
685 
686 /**
687  * Close the resource accessed by the AVIOContext s and free it.
688  * This function can only be used if s was opened by avio_open().
689  *
690  * The internal buffer is automatically flushed before closing the
691  * resource.
692  *
693  * @return 0 on success, an AVERROR < 0 on error.
694  * @see avio_closep
695  */
696 int avio_close(AVIOContext *s);
697 
698 /**
699  * Close the resource accessed by the AVIOContext *s, free it
700  * and set the pointer pointing to it to NULL.
701  * This function can only be used if s was opened by avio_open().
702  *
703  * The internal buffer is automatically flushed before closing the
704  * resource.
705  *
706  * @return 0 on success, an AVERROR < 0 on error.
707  * @see avio_close
708  */
709 int avio_closep(AVIOContext **s);
710 
711 
712 /**
713  * Open a write only memory stream.
714  *
715  * @param s new IO context
716  * @return zero if no error.
717  */
719 
720 /**
721  * Return the written size and a pointer to the buffer.
722  * The AVIOContext stream is left intact.
723  * The buffer must NOT be freed.
724  * No padding is added to the buffer.
725  *
726  * @param s IO context
727  * @param pbuffer pointer to a byte buffer
728  * @return the length of the byte buffer
729  */
730 int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
731 
732 /**
733  * Return the written size and a pointer to the buffer. The buffer
734  * must be freed with av_free().
735  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
736  *
737  * @param s IO context
738  * @param pbuffer pointer to a byte buffer
739  * @return the length of the byte buffer
740  */
741 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
742 
743 /**
744  * Iterate through names of available protocols.
745  *
746  * @param opaque A private pointer representing current protocol.
747  * It must be a pointer to NULL on first iteration and will
748  * be updated by successive calls to avio_enum_protocols.
749  * @param output If set to 1, iterate over output protocols,
750  * otherwise over input protocols.
751  *
752  * @return A static string containing the name of current protocol or NULL
753  */
754 const char *avio_enum_protocols(void **opaque, int output);
755 
756 /**
757  * Pause and resume playing - only meaningful if using a network streaming
758  * protocol (e.g. MMS).
759  *
760  * @param h IO context from which to call the read_pause function pointer
761  * @param pause 1 for pause, 0 for resume
762  */
763 int avio_pause(AVIOContext *h, int pause);
764 
765 /**
766  * Seek to a given timestamp relative to some component stream.
767  * Only meaningful if using a network streaming protocol (e.g. MMS.).
768  *
769  * @param h IO context from which to call the seek function pointers
770  * @param stream_index The stream index that the timestamp is relative to.
771  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
772  * units from the beginning of the presentation.
773  * If a stream_index >= 0 is used and the protocol does not support
774  * seeking based on component streams, the call will fail.
775  * @param timestamp timestamp in AVStream.time_base units
776  * or if there is no stream specified then in AV_TIME_BASE units.
777  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
778  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
779  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
780  * fail if used and not supported.
781  * @return >= 0 on success
782  * @see AVInputFormat::read_seek
783  */
784 int64_t avio_seek_time(AVIOContext *h, int stream_index,
785  int64_t timestamp, int flags);
786 
787 /* Avoid a warning. The header can not be included because it breaks c++. */
788 struct AVBPrint;
789 
790 /**
791  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
792  *
793  * @return 0 for success (max_size bytes read or EOF reached), negative error
794  * code otherwise
795  */
796 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
797 
798 /**
799  * Accept and allocate a client context on a server context.
800  * @param s the server context
801  * @param c the client context, must be unallocated
802  * @return >= 0 on success or a negative value corresponding
803  * to an AVERROR on failure
804  */
806 
807 /**
808  * Perform one step of the protocol handshake to accept a new client.
809  * This function must be called on a client returned by avio_accept() before
810  * using it as a read/write context.
811  * It is separate from avio_accept() because it may block.
812  * A step of the handshake is defined by places where the application may
813  * decide to change the proceedings.
814  * For example, on a protocol with a request header and a reply header, each
815  * one can constitute a step because the application may use the parameters
816  * from the request to change parameters in the reply; or each individual
817  * chunk of the request can constitute a step.
818  * If the handshake is already finished, avio_handshake() does nothing and
819  * returns 0 immediately.
820  *
821  * @param c the client context to perform the handshake on
822  * @return 0 on a complete and successful handshake
823  * > 0 if the handshake progressed, but is not complete
824  * < 0 for an AVERROR code
825  */
827 #endif /* AVFORMAT_AVIO_H */
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:1053
void avio_wb64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:450
const char const char void * val
Definition: avisynth_c.h:771
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:456
const char * s
Definition: avisynth_c.h:768
Bytestream IO Context.
Definition: avio.h:155
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:319
int64_t(* read_seek)(void *opaque, int stream_index, int64_t timestamp, int flags)
Seek to a given timestamp in stream with the specified stream_index.
Definition: avio.h:246
int avpriv_io_delete(const char *url)
Delete a resource.
Definition: avio.c:521
int avio_put_str16be(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16BE and write it.
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1317
int64_t filemode
Unix file mode, -1 if unknown.
Definition: avio.h:100
int(* short_seek_get)(void *opaque)
A callback that is used instead of short_seek_threshold.
Definition: avio.h:329
const char * fmt
Definition: avisynth_c.h:769
int64_t last_time
Definition: avio.h:323
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:218
int writeout_count
writeout statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:282
unsigned char * buf_end
End of the data, may be less than buffer+buffer_size if the read function returned less data than req...
Definition: avio.h:219
int write_flag
true if open for writing
Definition: avio.h:231
int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size)
Read contents of h into print buffer, up to max_size bytes, or up to EOF.
Definition: aviobuf.c:1158
Describes single entry of the directory.
Definition: avio.h:86
const char * b
Definition: vf_curves.c:113
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:231
unsigned char * buffer
Start of the buffer.
Definition: avio.h:216
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:314
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:227
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:223
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:752
int64_t maxsize
max filesize, used to limit allocations This field is internal to libavformat and access from outside...
Definition: avio.h:257
int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a UTF-16 string from pb and convert it to UTF-8.
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1288
void * opaque
Definition: avio.h:60
Trailer data, which doesn't contain actual content, but only for finalizing the output file...
Definition: avio.h:140
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:92
Public dictionary API.
int avio_accept(AVIOContext *s, AVIOContext **c)
Accept and allocate a client context on a server context.
Definition: aviobuf.c:1176
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:356
uint8_t
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:767
void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type)
Mark the written bytestream as a specific type.
Definition: aviobuf.c:480
const AVClass * av_class
A class for private options.
Definition: avio.h:168
A point in the output bytestream where a demuxer can start parsing (for non self synchronizing bytest...
Definition: avio.h:128
int64_t bytes_read
Bytes read statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:270
static int flags
Definition: log.c:57
ptrdiff_t size
Definition: opengl_enc.c:101
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:834
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:525
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:205
const OptionDef options[]
Definition: ffserver.c:3952
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:614
int avio_check(const char *url, int flags)
Return AVIO_FLAG_* access flags corresponding to the access permissions of the resource in url...
Definition: avio.c:480
void avio_wl64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:444
int max_packet_size
Definition: avio.h:232
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
AVIOContext * avio_alloc_context(unsigned char *buffer, int buffer_size, int write_flag, void *opaque, int(*read_packet)(void *opaque, uint8_t *buf, int buf_size), int(*write_packet)(void *opaque, uint8_t *buf, int buf_size), int64_t(*seek)(void *opaque, int64_t offset, int whence))
Allocate and initialize an AVIOContext for buffered I/O.
Definition: aviobuf.c:127
char * name
Filename.
Definition: avio.h:87
int(* write_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:226
int(* callback)(void *)
Definition: avio.h:59
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:461
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:225
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:736
const char * avio_enum_protocols(void **opaque, int output)
Iterate through names of available protocols.
Definition: protocols.c:96
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
Definition: aviobuf.c:1089
int utf8
Set to 1 when name is encoded with UTF-8, 0 otherwise.
Definition: avio.h:89
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:300
unsigned long checksum
Definition: avio.h:233
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
int direct
avio_read and avio_write should if possible be satisfied directly instead of going through a buffer...
Definition: avio.h:264
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:305
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:155
int seek_count
seek statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:276
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:605
int(* write_data_type)(void *opaque, uint8_t *buf, int buf_size, enum AVIODataMarkerType type, int64_t time)
A callback that is used instead of write_packet.
Definition: avio.h:310
This is any, unlabelled data.
Definition: avio.h:135
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:251
int void avio_flush(AVIOContext *s)
Force flushing of buffered data.
Definition: aviobuf.c:225
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:760
void avio_free_directory_entry(AVIODirEntry **entry)
Free entry allocated by avio_read_dir().
Definition: avio.c:603
int64_t access_timestamp
Time of last access in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:94
unsigned char * checksum_ptr
Definition: avio.h:234
AVIODataMarkerType
Different data types that can be returned via the AVIO write_data_type callback.
Definition: avio.h:111
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:474
int must_flush
true if the next seek should flush
Definition: avio.h:229
Libavformat version macros.
unsigned long(* update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size)
Definition: avio.h:235
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:91
int buffer_size
Maximum buffer size.
Definition: avio.h:217
int avpriv_io_move(const char *url_src, const char *url_dst)
Move or rename a resource.
Definition: avio.c:499
int avio_put_str(AVIOContext *s, const char *str)
Write a NULL-terminated string.
Definition: aviobuf.c:372
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
int type
Type of the entry.
Definition: avio.h:88
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:183
void * buf
Definition: avisynth_c.h:690
Definition: url.h:38
GLint GLenum type
Definition: opengl_enc.c:105
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost)
Definition: ffmpeg.c:669
Describe the class of an AVClass context structure.
Definition: log.h:67
int64_t group_id
Group ID of owner, -1 if unknown.
Definition: avio.h:99
const char * avio_find_protocol_name(const char *url)
Return the name of the protocol that will handle the passed URL.
Definition: avio.c:473
int avio_put_str16le(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16LE and write it.
int avio_open2(AVIOContext **s, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:1077
int short_seek_threshold
Threshold to favor readahead over seek.
Definition: avio.h:295
int avio_handshake(AVIOContext *c)
Perform one step of the protocol handshake to accept a new client.
Definition: aviobuf.c:1188
int avio_close_dir(AVIODirContext **s)
Close directory.
Definition: avio.c:588
int ignore_boundary_point
If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT, but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly small chunks of data returned from the callback).
Definition: avio.h:317
int error
contains the error code or 0 if no error happened
Definition: avio.h:236
void avio_wl24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:468
int avio_pause(AVIOContext *h, int pause)
Pause and resume playing - only meaningful if using a network streaming protocol (e.g.
Definition: aviobuf.c:1132
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:240
void avio_wb16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:462
#define attribute_deprecated
Definition: attributes.h:94
int orig_buffer_size
Original buffer size used internally after probing and ensure seekback to reset the buffer size This ...
Definition: avio.h:289
enum AVIODataMarkerType current_type
Internal, not meant to be used from outside of AVIOContext.
Definition: avio.h:322
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:720
int
common internal and external API header
int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen)
int64_t status_change_timestamp
Time of last status change in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:96
AVIODirEntryType
Directory entry types.
Definition: avio.h:66
static double c[64]
int64_t pos
position in the file of the current buffer
Definition: avio.h:228
int64_t avio_seek_time(AVIOContext *h, int stream_index, int64_t timestamp, int flags)
Seek to a given timestamp relative to some component stream.
Definition: aviobuf.c:1139
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
Definition: avio.c:575
A point in the output bytestream where a decoder can start decoding (i.e.
Definition: avio.h:122
int eof_reached
true if eof reached
Definition: avio.h:230
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:98
int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
Open directory for reading.
Definition: avio.c:537
void avio_wb32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:364
#define av_always_inline
Definition: attributes.h:39
int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a string from pb into buf.
Definition: aviobuf.c:792
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:338
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:728
struct URLContext * url_context
Definition: avio.h:104
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
Definition: aviobuf.c:1112
uint64_t avio_rl64(AVIOContext *s)
Definition: aviobuf.c:744
Header data; this needs to be present for the stream to be decodeable.
Definition: avio.h:115
GLuint buffer
Definition: opengl_enc.c:102
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2
int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1300