FFmpeg  n5.1.2
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 #include <stdio.h>
31 
32 #include "libavutil/attributes.h"
33 #include "libavutil/dict.h"
34 #include "libavutil/log.h"
35 
37 
38 /**
39  * Seeking works like for a local file.
40  */
41 #define AVIO_SEEKABLE_NORMAL (1 << 0)
42 
43 /**
44  * Seeking by timestamp with avio_seek_time() is possible.
45  */
46 #define AVIO_SEEKABLE_TIME (1 << 1)
47 
48 /**
49  * Callback for checking whether to abort blocking functions.
50  * AVERROR_EXIT is returned in this case by the interrupted
51  * function. During blocking operations, callback is called with
52  * opaque as parameter. If the callback returns 1, the
53  * blocking operation will be aborted.
54  *
55  * No members can be added to this struct without a major bump, if
56  * new elements have been added after this struct in AVFormatContext
57  * or AVIOContext.
58  */
59 typedef struct AVIOInterruptCB {
60  int (*callback)(void*);
61  void *opaque;
63 
64 /**
65  * Directory entry types.
66  */
79 };
80 
81 /**
82  * Describes single entry of the directory.
83  *
84  * Only name and type fields are guaranteed be set.
85  * Rest of fields are protocol or/and platform dependent and might be unknown.
86  */
87 typedef struct AVIODirEntry {
88  char *name; /**< Filename */
89  int type; /**< Type of the entry */
90  int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise.
91  Name can be encoded with UTF-8 even though 0 is set. */
92  int64_t size; /**< File size in bytes, -1 if unknown. */
93  int64_t modification_timestamp; /**< Time of last modification in microseconds since unix
94  epoch, -1 if unknown. */
95  int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch,
96  -1 if unknown. */
97  int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix
98  epoch, -1 if unknown. */
99  int64_t user_id; /**< User ID of owner, -1 if unknown. */
100  int64_t group_id; /**< Group ID of owner, -1 if unknown. */
101  int64_t filemode; /**< Unix file mode, -1 if unknown. */
102 } AVIODirEntry;
103 
104 typedef struct AVIODirContext {
105  struct URLContext *url_context;
107 
108 /**
109  * Different data types that can be returned via the AVIO
110  * write_data_type callback.
111  */
113  /**
114  * Header data; this needs to be present for the stream to be decodeable.
115  */
117  /**
118  * A point in the output bytestream where a decoder can start decoding
119  * (i.e. a keyframe). A demuxer/decoder given the data flagged with
120  * AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT,
121  * should give decodeable results.
122  */
124  /**
125  * A point in the output bytestream where a demuxer can start parsing
126  * (for non self synchronizing bytestream formats). That is, any
127  * non-keyframe packet start point.
128  */
130  /**
131  * This is any, unlabelled data. It can either be a muxer not marking
132  * any positions at all, it can be an actual boundary/sync point
133  * that the muxer chooses not to mark, or a later part of a packet/fragment
134  * that is cut into multiple write callbacks due to limited IO buffer size.
135  */
137  /**
138  * Trailer data, which doesn't contain actual content, but only for
139  * finalizing the output file.
140  */
142  /**
143  * A point in the output bytestream where the underlying AVIOContext might
144  * flush the buffer depending on latency or buffering requirements. Typically
145  * means the end of a packet.
146  */
148 };
149 
150 /**
151  * Bytestream IO Context.
152  * New public fields can be added with minor version bumps.
153  * Removal, reordering and changes to existing public fields require
154  * a major version bump.
155  * sizeof(AVIOContext) must not be used outside libav*.
156  *
157  * @note None of the function pointers in AVIOContext should be called
158  * directly, they should only be set by the client application
159  * when implementing custom I/O. Normally these are set to the
160  * function pointers specified in avio_alloc_context()
161  */
162 typedef struct AVIOContext {
163  /**
164  * A class for private options.
165  *
166  * If this AVIOContext is created by avio_open2(), av_class is set and
167  * passes the options down to protocols.
168  *
169  * If this AVIOContext is manually allocated, then av_class may be set by
170  * the caller.
171  *
172  * warning -- this field can be NULL, be sure to not pass this AVIOContext
173  * to any av_opt_* functions in that case.
174  */
176 
177  /*
178  * The following shows the relationship between buffer, buf_ptr,
179  * buf_ptr_max, buf_end, buf_size, and pos, when reading and when writing
180  * (since AVIOContext is used for both):
181  *
182  **********************************************************************************
183  * READING
184  **********************************************************************************
185  *
186  * | buffer_size |
187  * |---------------------------------------|
188  * | |
189  *
190  * buffer buf_ptr buf_end
191  * +---------------+-----------------------+
192  * |/ / / / / / / /|/ / / / / / /| |
193  * read buffer: |/ / consumed / | to be read /| |
194  * |/ / / / / / / /|/ / / / / / /| |
195  * +---------------+-----------------------+
196  *
197  * pos
198  * +-------------------------------------------+-----------------+
199  * input file: | | |
200  * +-------------------------------------------+-----------------+
201  *
202  *
203  **********************************************************************************
204  * WRITING
205  **********************************************************************************
206  *
207  * | buffer_size |
208  * |--------------------------------------|
209  * | |
210  *
211  * buf_ptr_max
212  * buffer (buf_ptr) buf_end
213  * +-----------------------+--------------+
214  * |/ / / / / / / / / / / /| |
215  * write buffer: | / / to be flushed / / | |
216  * |/ / / / / / / / / / / /| |
217  * +-----------------------+--------------+
218  * buf_ptr can be in this
219  * due to a backward seek
220  *
221  * pos
222  * +-------------+----------------------------------------------+
223  * output file: | | |
224  * +-------------+----------------------------------------------+
225  *
226  */
227  unsigned char *buffer; /**< Start of the buffer. */
228  int buffer_size; /**< Maximum buffer size */
229  unsigned char *buf_ptr; /**< Current position in the buffer */
230  unsigned char *buf_end; /**< End of the data, may be less than
231  buffer+buffer_size if the read function returned
232  less data than requested, e.g. for streams where
233  no more data has been received yet. */
234  void *opaque; /**< A private pointer, passed to the read/write/seek/...
235  functions. */
236  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
237  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
238  int64_t (*seek)(void *opaque, int64_t offset, int whence);
239  int64_t pos; /**< position in the file of the current buffer */
240  int eof_reached; /**< true if was unable to read due to error or eof */
241  int error; /**< contains the error code or 0 if no error happened */
242  int write_flag; /**< true if open for writing */
244  int min_packet_size; /**< Try to buffer at least this amount of data
245  before flushing it. */
246  unsigned long checksum;
247  unsigned char *checksum_ptr;
248  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
249  /**
250  * Pause or resume playback for network streaming protocols - e.g. MMS.
251  */
252  int (*read_pause)(void *opaque, int pause);
253  /**
254  * Seek to a given timestamp in stream with the specified stream_index.
255  * Needed for some network streaming protocols which don't support seeking
256  * to byte position.
257  */
258  int64_t (*read_seek)(void *opaque, int stream_index,
259  int64_t timestamp, int flags);
260  /**
261  * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
262  */
263  int seekable;
264 
265  /**
266  * avio_read and avio_write should if possible be satisfied directly
267  * instead of going through a buffer, and avio_seek will always
268  * call the underlying seek function directly.
269  */
270  int direct;
271 
272  /**
273  * ',' separated list of allowed protocols.
274  */
275  const char *protocol_whitelist;
276 
277  /**
278  * ',' separated list of disallowed protocols.
279  */
280  const char *protocol_blacklist;
281 
282  /**
283  * A callback that is used instead of write_packet.
284  */
285  int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size,
286  enum AVIODataMarkerType type, int64_t time);
287  /**
288  * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
289  * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
290  * small chunks of data returned from the callback).
291  */
293 
294 #if FF_API_AVIOCONTEXT_WRITTEN
295  /**
296  * @deprecated field utilized privately by libavformat. For a public
297  * statistic of how many bytes were written out, see
298  * AVIOContext::bytes_written.
299  */
301  int64_t written;
302 #endif
303 
304  /**
305  * Maximum reached position before a backward seek in the write buffer,
306  * used keeping track of already written data for a later flush.
307  */
308  unsigned char *buf_ptr_max;
309 
310  /**
311  * Read-only statistic of bytes read for this AVIOContext.
312  */
313  int64_t bytes_read;
314 
315  /**
316  * Read-only statistic of bytes written for this AVIOContext.
317  */
318  int64_t bytes_written;
319 } AVIOContext;
320 
321 /**
322  * Return the name of the protocol that will handle the passed URL.
323  *
324  * NULL is returned if no protocol could be found for the given URL.
325  *
326  * @return Name of the protocol or NULL.
327  */
328 const char *avio_find_protocol_name(const char *url);
329 
330 /**
331  * Return AVIO_FLAG_* access flags corresponding to the access permissions
332  * of the resource in url, or a negative value corresponding to an
333  * AVERROR code in case of failure. The returned access flags are
334  * masked by the value in flags.
335  *
336  * @note This function is intrinsically unsafe, in the sense that the
337  * checked resource may change its existence or permission status from
338  * one call to another. Thus you should not trust the returned value,
339  * unless you are sure that no other processes are accessing the
340  * checked resource.
341  */
342 int avio_check(const char *url, int flags);
343 
344 /**
345  * Open directory for reading.
346  *
347  * @param s directory read context. Pointer to a NULL pointer must be passed.
348  * @param url directory to be listed.
349  * @param options A dictionary filled with protocol-private options. On return
350  * this parameter will be destroyed and replaced with a dictionary
351  * containing options that were not found. May be NULL.
352  * @return >=0 on success or negative on error.
353  */
354 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
355 
356 /**
357  * Get next directory entry.
358  *
359  * Returned entry must be freed with avio_free_directory_entry(). In particular
360  * it may outlive AVIODirContext.
361  *
362  * @param s directory read context.
363  * @param[out] next next entry or NULL when no more entries.
364  * @return >=0 on success or negative on error. End of list is not considered an
365  * error.
366  */
368 
369 /**
370  * Close directory.
371  *
372  * @note Entries created using avio_read_dir() are not deleted and must be
373  * freeded with avio_free_directory_entry().
374  *
375  * @param s directory read context.
376  * @return >=0 on success or negative on error.
377  */
379 
380 /**
381  * Free entry allocated by avio_read_dir().
382  *
383  * @param entry entry to be freed.
384  */
386 
387 /**
388  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
389  * freed with avio_context_free().
390  *
391  * @param buffer Memory block for input/output operations via AVIOContext.
392  * The buffer must be allocated with av_malloc() and friends.
393  * It may be freed and replaced with a new buffer by libavformat.
394  * AVIOContext.buffer holds the buffer currently in use,
395  * which must be later freed with av_free().
396  * @param buffer_size The buffer size is very important for performance.
397  * For protocols with fixed blocksize it should be set to this blocksize.
398  * For others a typical size is a cache page, e.g. 4kb.
399  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
400  * @param opaque An opaque pointer to user-specific data.
401  * @param read_packet A function for refilling the buffer, may be NULL.
402  * For stream protocols, must never return 0 but rather
403  * a proper AVERROR code.
404  * @param write_packet A function for writing the buffer contents, may be NULL.
405  * The function may not change the input buffers content.
406  * @param seek A function for seeking to specified byte position, may be NULL.
407  *
408  * @return Allocated AVIOContext or NULL on failure.
409  */
411  unsigned char *buffer,
412  int buffer_size,
413  int write_flag,
414  void *opaque,
415  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
416  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
417  int64_t (*seek)(void *opaque, int64_t offset, int whence));
418 
419 /**
420  * Free the supplied IO context and everything associated with it.
421  *
422  * @param s Double pointer to the IO context. This function will write NULL
423  * into s.
424  */
426 
427 void avio_w8(AVIOContext *s, int b);
428 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
429 void avio_wl64(AVIOContext *s, uint64_t val);
430 void avio_wb64(AVIOContext *s, uint64_t val);
431 void avio_wl32(AVIOContext *s, unsigned int val);
432 void avio_wb32(AVIOContext *s, unsigned int val);
433 void avio_wl24(AVIOContext *s, unsigned int val);
434 void avio_wb24(AVIOContext *s, unsigned int val);
435 void avio_wl16(AVIOContext *s, unsigned int val);
436 void avio_wb16(AVIOContext *s, unsigned int val);
437 
438 /**
439  * Write a NULL-terminated string.
440  * @return number of bytes written.
441  */
442 int avio_put_str(AVIOContext *s, const char *str);
443 
444 /**
445  * Convert an UTF-8 string to UTF-16LE and write it.
446  * @param s the AVIOContext
447  * @param str NULL-terminated UTF-8 string
448  *
449  * @return number of bytes written.
450  */
451 int avio_put_str16le(AVIOContext *s, const char *str);
452 
453 /**
454  * Convert an UTF-8 string to UTF-16BE and write it.
455  * @param s the AVIOContext
456  * @param str NULL-terminated UTF-8 string
457  *
458  * @return number of bytes written.
459  */
460 int avio_put_str16be(AVIOContext *s, const char *str);
461 
462 /**
463  * Mark the written bytestream as a specific type.
464  *
465  * Zero-length ranges are omitted from the output.
466  *
467  * @param time the stream time the current bytestream pos corresponds to
468  * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
469  * applicable
470  * @param type the kind of data written starting at the current pos
471  */
472 void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
473 
474 /**
475  * ORing this as the "whence" parameter to a seek function causes it to
476  * return the filesize without seeking anywhere. Supporting this is optional.
477  * If it is not supported then the seek function will return <0.
478  */
479 #define AVSEEK_SIZE 0x10000
480 
481 /**
482  * Passing this flag as the "whence" parameter to a seek function causes it to
483  * seek by any means (like reopening and linear reading) or other normally unreasonable
484  * means that can be extremely slow.
485  * This may be ignored by the seek code.
486  */
487 #define AVSEEK_FORCE 0x20000
488 
489 /**
490  * fseek() equivalent for AVIOContext.
491  * @return new position or AVERROR.
492  */
493 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
494 
495 /**
496  * Skip given number of bytes forward
497  * @return new position or AVERROR.
498  */
499 int64_t avio_skip(AVIOContext *s, int64_t offset);
500 
501 /**
502  * ftell() equivalent for AVIOContext.
503  * @return position or AVERROR.
504  */
506 {
507  return avio_seek(s, 0, SEEK_CUR);
508 }
509 
510 /**
511  * Get the filesize.
512  * @return filesize or AVERROR
513  */
514 int64_t avio_size(AVIOContext *s);
515 
516 /**
517  * Similar to feof() but also returns nonzero on read errors.
518  * @return non zero if and only if at end of file or a read error happened when reading.
519  */
521 
522 /**
523  * Writes a formatted string to the context taking a va_list.
524  * @return number of bytes written, < 0 on error.
525  */
526 int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap);
527 
528 /**
529  * Writes a formatted string to the context.
530  * @return number of bytes written, < 0 on error.
531  */
532 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
533 
534 /**
535  * Write a NULL terminated array of strings to the context.
536  * Usually you don't need to use this function directly but its macro wrapper,
537  * avio_print.
538  */
539 void avio_print_string_array(AVIOContext *s, const char *strings[]);
540 
541 /**
542  * Write strings (const char *) to the context.
543  * This is a convenience macro around avio_print_string_array and it
544  * automatically creates the string array from the variable argument list.
545  * For simple string concatenations this function is more performant than using
546  * avio_printf since it does not need a temporary buffer.
547  */
548 #define avio_print(s, ...) \
549  avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
550 
551 /**
552  * Force flushing of buffered data.
553  *
554  * For write streams, force the buffered data to be immediately written to the output,
555  * without to wait to fill the internal buffer.
556  *
557  * For read streams, discard all currently buffered data, and advance the
558  * reported file position to that of the underlying stream. This does not
559  * read new data, and does not perform any seeks.
560  */
562 
563 /**
564  * Read size bytes from AVIOContext into buf.
565  * @return number of bytes read or AVERROR
566  */
567 int avio_read(AVIOContext *s, unsigned char *buf, int size);
568 
569 /**
570  * Read size bytes from AVIOContext into buf. Unlike avio_read(), this is allowed
571  * to read fewer bytes than requested. The missing bytes can be read in the next
572  * call. This always tries to read at least 1 byte.
573  * Useful to reduce latency in certain cases.
574  * @return number of bytes read or AVERROR
575  */
576 int avio_read_partial(AVIOContext *s, unsigned char *buf, int size);
577 
578 /**
579  * @name Functions for reading from AVIOContext
580  * @{
581  *
582  * @note return 0 if EOF, so you cannot use it if EOF handling is
583  * necessary
584  */
586 unsigned int avio_rl16(AVIOContext *s);
587 unsigned int avio_rl24(AVIOContext *s);
588 unsigned int avio_rl32(AVIOContext *s);
589 uint64_t avio_rl64(AVIOContext *s);
590 unsigned int avio_rb16(AVIOContext *s);
591 unsigned int avio_rb24(AVIOContext *s);
592 unsigned int avio_rb32(AVIOContext *s);
593 uint64_t avio_rb64(AVIOContext *s);
594 /**
595  * @}
596  */
597 
598 /**
599  * Read a string from pb into buf. The reading will terminate when either
600  * a NULL character was encountered, maxlen bytes have been read, or nothing
601  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
602  * will be truncated if buf is too small.
603  * Note that the string is not interpreted or validated in any way, it
604  * might get truncated in the middle of a sequence for multi-byte encodings.
605  *
606  * @return number of bytes read (is always <= maxlen).
607  * If reading ends on EOF or error, the return value will be one more than
608  * bytes actually read.
609  */
610 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
611 
612 /**
613  * Read a UTF-16 string from pb and convert it to UTF-8.
614  * The reading will terminate when either a null or invalid character was
615  * encountered or maxlen bytes have been read.
616  * @return number of bytes read (is always <= maxlen)
617  */
618 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
619 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
620 
621 
622 /**
623  * @name URL open modes
624  * The flags argument to avio_open must be one of the following
625  * constants, optionally ORed with other flags.
626  * @{
627  */
628 #define AVIO_FLAG_READ 1 /**< read-only */
629 #define AVIO_FLAG_WRITE 2 /**< write-only */
630 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
631 /**
632  * @}
633  */
634 
635 /**
636  * Use non-blocking mode.
637  * If this flag is set, operations on the context will return
638  * AVERROR(EAGAIN) if they can not be performed immediately.
639  * If this flag is not set, operations on the context will never return
640  * AVERROR(EAGAIN).
641  * Note that this flag does not affect the opening/connecting of the
642  * context. Connecting a protocol will always block if necessary (e.g. on
643  * network protocols) but never hang (e.g. on busy devices).
644  * Warning: non-blocking protocols is work-in-progress; this flag may be
645  * silently ignored.
646  */
647 #define AVIO_FLAG_NONBLOCK 8
648 
649 /**
650  * Use direct mode.
651  * avio_read and avio_write should if possible be satisfied directly
652  * instead of going through a buffer, and avio_seek will always
653  * call the underlying seek function directly.
654  */
655 #define AVIO_FLAG_DIRECT 0x8000
656 
657 /**
658  * Create and initialize a AVIOContext for accessing the
659  * resource indicated by url.
660  * @note When the resource indicated by url has been opened in
661  * read+write mode, the AVIOContext can be used only for writing.
662  *
663  * @param s Used to return the pointer to the created AVIOContext.
664  * In case of failure the pointed to value is set to NULL.
665  * @param url resource to access
666  * @param flags flags which control how the resource indicated by url
667  * is to be opened
668  * @return >= 0 in case of success, a negative value corresponding to an
669  * AVERROR code in case of failure
670  */
671 int avio_open(AVIOContext **s, const char *url, int flags);
672 
673 /**
674  * Create and initialize a AVIOContext for accessing the
675  * resource indicated by url.
676  * @note When the resource indicated by url has been opened in
677  * read+write mode, the AVIOContext can be used only for writing.
678  *
679  * @param s Used to return the pointer to the created AVIOContext.
680  * In case of failure the pointed to value is set to NULL.
681  * @param url resource to access
682  * @param flags flags which control how the resource indicated by url
683  * is to be opened
684  * @param int_cb an interrupt callback to be used at the protocols level
685  * @param options A dictionary filled with protocol-private options. On return
686  * this parameter will be destroyed and replaced with a dict containing options
687  * that were not found. May be NULL.
688  * @return >= 0 in case of success, a negative value corresponding to an
689  * AVERROR code in case of failure
690  */
691 int avio_open2(AVIOContext **s, const char *url, int flags,
692  const AVIOInterruptCB *int_cb, AVDictionary **options);
693 
694 /**
695  * Close the resource accessed by the AVIOContext s and free it.
696  * This function can only be used if s was opened by avio_open().
697  *
698  * The internal buffer is automatically flushed before closing the
699  * resource.
700  *
701  * @return 0 on success, an AVERROR < 0 on error.
702  * @see avio_closep
703  */
705 
706 /**
707  * Close the resource accessed by the AVIOContext *s, free it
708  * and set the pointer pointing to it to NULL.
709  * This function can only be used if s was opened by avio_open().
710  *
711  * The internal buffer is automatically flushed before closing the
712  * resource.
713  *
714  * @return 0 on success, an AVERROR < 0 on error.
715  * @see avio_close
716  */
718 
719 
720 /**
721  * Open a write only memory stream.
722  *
723  * @param s new IO context
724  * @return zero if no error.
725  */
727 
728 /**
729  * Return the written size and a pointer to the buffer.
730  * The AVIOContext stream is left intact.
731  * The buffer must NOT be freed.
732  * No padding is added to the buffer.
733  *
734  * @param s IO context
735  * @param pbuffer pointer to a byte buffer
736  * @return the length of the byte buffer
737  */
738 int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
739 
740 /**
741  * Return the written size and a pointer to the buffer. The buffer
742  * must be freed with av_free().
743  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
744  *
745  * @param s IO context
746  * @param pbuffer pointer to a byte buffer
747  * @return the length of the byte buffer
748  */
749 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
750 
751 /**
752  * Iterate through names of available protocols.
753  *
754  * @param opaque A private pointer representing current protocol.
755  * It must be a pointer to NULL on first iteration and will
756  * be updated by successive calls to avio_enum_protocols.
757  * @param output If set to 1, iterate over output protocols,
758  * otherwise over input protocols.
759  *
760  * @return A static string containing the name of current protocol or NULL
761  */
762 const char *avio_enum_protocols(void **opaque, int output);
763 
764 /**
765  * Get AVClass by names of available protocols.
766  *
767  * @return A AVClass of input protocol name or NULL
768  */
769 const AVClass *avio_protocol_get_class(const char *name);
770 
771 /**
772  * Pause and resume playing - only meaningful if using a network streaming
773  * protocol (e.g. MMS).
774  *
775  * @param h IO context from which to call the read_pause function pointer
776  * @param pause 1 for pause, 0 for resume
777  */
778 int avio_pause(AVIOContext *h, int pause);
779 
780 /**
781  * Seek to a given timestamp relative to some component stream.
782  * Only meaningful if using a network streaming protocol (e.g. MMS.).
783  *
784  * @param h IO context from which to call the seek function pointers
785  * @param stream_index The stream index that the timestamp is relative to.
786  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
787  * units from the beginning of the presentation.
788  * If a stream_index >= 0 is used and the protocol does not support
789  * seeking based on component streams, the call will fail.
790  * @param timestamp timestamp in AVStream.time_base units
791  * or if there is no stream specified then in AV_TIME_BASE units.
792  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
793  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
794  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
795  * fail if used and not supported.
796  * @return >= 0 on success
797  * @see AVInputFormat::read_seek
798  */
799 int64_t avio_seek_time(AVIOContext *h, int stream_index,
800  int64_t timestamp, int flags);
801 
802 /* Avoid a warning. The header can not be included because it breaks c++. */
803 struct AVBPrint;
804 
805 /**
806  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
807  *
808  * @return 0 for success (max_size bytes read or EOF reached), negative error
809  * code otherwise
810  */
811 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
812 
813 /**
814  * Accept and allocate a client context on a server context.
815  * @param s the server context
816  * @param c the client context, must be unallocated
817  * @return >= 0 on success or a negative value corresponding
818  * to an AVERROR on failure
819  */
821 
822 /**
823  * Perform one step of the protocol handshake to accept a new client.
824  * This function must be called on a client returned by avio_accept() before
825  * using it as a read/write context.
826  * It is separate from avio_accept() because it may block.
827  * A step of the handshake is defined by places where the application may
828  * decide to change the proceedings.
829  * For example, on a protocol with a request header and a reply header, each
830  * one can constitute a step because the application may use the parameters
831  * from the request to change parameters in the reply; or each individual
832  * chunk of the request can constitute a step.
833  * If the handshake is already finished, avio_handshake() does nothing and
834  * returns 0 immediately.
835  *
836  * @param c the client context to perform the handshake on
837  * @return 0 on a complete and successful handshake
838  * > 0 if the handshake progressed, but is not complete
839  * < 0 for an AVERROR code
840  */
842 #endif /* AVFORMAT_AVIO_H */
Macro definitions for various function/variable attributes.
#define av_always_inline
Definition: attributes.h:45
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:161
#define attribute_deprecated
Definition: attributes.h:100
int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen)
void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type)
Mark the written bytestream as a specific type.
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
void avio_wl64(AVIOContext *s, uint64_t val)
int avio_handshake(AVIOContext *c)
Perform one step of the protocol handshake to accept a new client.
uint64_t avio_rb64(AVIOContext *s)
void avio_wl32(AVIOContext *s, unsigned int val)
int avio_pause(AVIOContext *h, int pause)
Pause and resume playing - only meaningful if using a network streaming protocol (e....
void avio_wl16(AVIOContext *s, unsigned int val)
int avio_put_str(AVIOContext *s, const char *str)
Write a NULL-terminated string.
void avio_w8(AVIOContext *s, int b)
void avio_wb32(AVIOContext *s, unsigned int val)
int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap)
Writes a formatted string to the context taking a va_list.
void avio_wb16(AVIOContext *s, unsigned int val)
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
int64_t avio_size(AVIOContext *s)
Get the filesize.
unsigned int avio_rb16(AVIOContext *s)
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_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
AVIODataMarkerType
Different data types that can be returned via the AVIO write_data_type callback.
Definition: avio.h:112
@ AVIO_DATA_MARKER_BOUNDARY_POINT
A point in the output bytestream where a demuxer can start parsing (for non self synchronizing bytest...
Definition: avio.h:129
@ AVIO_DATA_MARKER_TRAILER
Trailer data, which doesn't contain actual content, but only for finalizing the output file.
Definition: avio.h:141
@ AVIO_DATA_MARKER_HEADER
Header data; this needs to be present for the stream to be decodeable.
Definition: avio.h:116
@ AVIO_DATA_MARKER_UNKNOWN
This is any, unlabelled data.
Definition: avio.h:136
@ AVIO_DATA_MARKER_FLUSH_POINT
A point in the output bytestream where the underlying AVIOContext might flush the buffer depending on...
Definition: avio.h:147
@ AVIO_DATA_MARKER_SYNC_POINT
A point in the output bytestream where a decoder can start decoding (i.e.
Definition: avio.h:123
int avio_put_str16le(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16LE and write it.
const char * avio_enum_protocols(void **opaque, int output)
Iterate through names of available protocols.
int avio_read_partial(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
const char * avio_find_protocol_name(const char *url)
Return the name of the protocol that will handle the passed URL.
int avio_close_dir(AVIODirContext **s)
Close directory.
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:505
unsigned int avio_rl16(AVIOContext *s)
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2
Writes a formatted string to the context.
int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
Open directory for reading.
void avio_wb24(AVIOContext *s, unsigned int val)
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.
int avio_accept(AVIOContext *s, AVIOContext **c)
Accept and allocate a client context on a server context.
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
void avio_wb64(AVIOContext *s, uint64_t val)
void avio_free_directory_entry(AVIODirEntry **entry)
Free entry allocated by avio_read_dir().
void avio_wl24(AVIOContext *s, unsigned int val)
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
int avio_check(const char *url, int flags)
Return AVIO_FLAG_* access flags corresponding to the access permissions of the resource in url,...
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
unsigned int avio_rl32(AVIOContext *s)
int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a string from pb into buf.
unsigned int avio_rl24(AVIOContext *s)
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
int avio_put_str16be(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16BE and write it.
void avio_context_free(AVIOContext **s)
Free the supplied IO context and everything associated with it.
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
void avio_flush(AVIOContext *s)
Force flushing of buffered data.
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
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.
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
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.
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
unsigned int avio_rb24(AVIOContext *s)
AVIODirEntryType
Directory entry types.
Definition: avio.h:67
@ AVIO_ENTRY_UNKNOWN
Definition: avio.h:68
@ AVIO_ENTRY_NAMED_PIPE
Definition: avio.h:72
@ AVIO_ENTRY_WORKGROUP
Definition: avio.h:78
@ AVIO_ENTRY_SERVER
Definition: avio.h:76
@ AVIO_ENTRY_SHARE
Definition: avio.h:77
@ AVIO_ENTRY_BLOCK_DEVICE
Definition: avio.h:69
@ AVIO_ENTRY_SYMBOLIC_LINK
Definition: avio.h:73
@ AVIO_ENTRY_DIRECTORY
Definition: avio.h:71
@ AVIO_ENTRY_CHARACTER_DEVICE
Definition: avio.h:70
@ AVIO_ENTRY_FILE
Definition: avio.h:75
@ AVIO_ENTRY_SOCKET
Definition: avio.h:74
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.
const AVClass * avio_protocol_get_class(const char *name)
Get AVClass by names of available protocols.
int void avio_print_string_array(AVIOContext *s, const char *strings[])
Write a NULL terminated array of strings to the context.
unsigned int avio_rb32(AVIOContext *s)
int avio_r8(AVIOContext *s)
int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
uint64_t avio_rl64(AVIOContext *s)
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
Public dictionary API.
struct AVDictionary AVDictionary
Definition: dict.h:84
Libavformat version macros.
Describe the class of an AVClass context structure.
Definition: log.h:66
Bytestream IO Context.
Definition: avio.h:162
int buffer_size
Maximum buffer size.
Definition: avio.h:228
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:230
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:263
unsigned char * checksum_ptr
Definition: avio.h:247
const AVClass * av_class
A class for private options.
Definition: avio.h:175
int64_t bytes_read
Read-only statistic of bytes read for this AVIOContext.
Definition: avio.h:313
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:229
int ignore_boundary_point
If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,...
Definition: avio.h:292
int min_packet_size
Try to buffer at least this amount of data before flushing it.
Definition: avio.h:244
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:238
unsigned char * buf_ptr_max
Maximum reached position before a backward seek in the write buffer, used keeping track of already wr...
Definition: avio.h:308
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:275
int64_t pos
position in the file of the current buffer
Definition: avio.h:239
unsigned long(* update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size)
Definition: avio.h:248
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:280
int64_t bytes_written
Read-only statistic of bytes written for this AVIOContext.
Definition: avio.h:318
unsigned char * buffer
Start of the buffer.
Definition: avio.h:227
unsigned long checksum
Definition: avio.h:246
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:236
int eof_reached
true if was unable to read due to error or eof
Definition: avio.h:240
int write_flag
true if open for writing
Definition: avio.h:242
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:258
int max_packet_size
Definition: avio.h:243
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:252
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:285
int direct
avio_read and avio_write should if possible be satisfied directly instead of going through a buffer,...
Definition: avio.h:270
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:234
int(* write_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:237
int error
contains the error code or 0 if no error happened
Definition: avio.h:241
struct URLContext * url_context
Definition: avio.h:105
Describes single entry of the directory.
Definition: avio.h:87
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:99
int type
Type of the entry.
Definition: avio.h:89
int64_t access_timestamp
Time of last access in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:95
int64_t status_change_timestamp
Time of last status change in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:97
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:92
int64_t group_id
Group ID of owner, -1 if unknown.
Definition: avio.h:100
char * name
Filename.
Definition: avio.h:88
int utf8
Set to 1 when name is encoded with UTF-8, 0 otherwise.
Definition: avio.h:90
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:93
int64_t filemode
Unix file mode, -1 if unknown.
Definition: avio.h:101
Callback for checking whether to abort blocking functions.
Definition: avio.h:59
void * opaque
Definition: avio.h:61
int(* callback)(void *)
Definition: avio.h:60