FFmpeg  5.0.1
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 {
104  struct URLContext *url_context;
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  * A point in the output bytestream where the underlying AVIOContext might
143  * flush the buffer depending on latency or buffering requirements. Typically
144  * means the end of a packet.
145  */
147 };
148 
149 /**
150  * Bytestream IO Context.
151  * New public fields can be added with minor version bumps.
152  * Removal, reordering and changes to existing public fields require
153  * a major version bump.
154  * sizeof(AVIOContext) must not be used outside libav*.
155  *
156  * @note None of the function pointers in AVIOContext should be called
157  * directly, they should only be set by the client application
158  * when implementing custom I/O. Normally these are set to the
159  * function pointers specified in avio_alloc_context()
160  */
161 typedef struct AVIOContext {
162  /**
163  * A class for private options.
164  *
165  * If this AVIOContext is created by avio_open2(), av_class is set and
166  * passes the options down to protocols.
167  *
168  * If this AVIOContext is manually allocated, then av_class may be set by
169  * the caller.
170  *
171  * warning -- this field can be NULL, be sure to not pass this AVIOContext
172  * to any av_opt_* functions in that case.
173  */
175 
176  /*
177  * The following shows the relationship between buffer, buf_ptr,
178  * buf_ptr_max, buf_end, buf_size, and pos, when reading and when writing
179  * (since AVIOContext is used for both):
180  *
181  **********************************************************************************
182  * READING
183  **********************************************************************************
184  *
185  * | buffer_size |
186  * |---------------------------------------|
187  * | |
188  *
189  * buffer buf_ptr buf_end
190  * +---------------+-----------------------+
191  * |/ / / / / / / /|/ / / / / / /| |
192  * read buffer: |/ / consumed / | to be read /| |
193  * |/ / / / / / / /|/ / / / / / /| |
194  * +---------------+-----------------------+
195  *
196  * pos
197  * +-------------------------------------------+-----------------+
198  * input file: | | |
199  * +-------------------------------------------+-----------------+
200  *
201  *
202  **********************************************************************************
203  * WRITING
204  **********************************************************************************
205  *
206  * | buffer_size |
207  * |--------------------------------------|
208  * | |
209  *
210  * buf_ptr_max
211  * buffer (buf_ptr) buf_end
212  * +-----------------------+--------------+
213  * |/ / / / / / / / / / / /| |
214  * write buffer: | / / to be flushed / / | |
215  * |/ / / / / / / / / / / /| |
216  * +-----------------------+--------------+
217  * buf_ptr can be in this
218  * due to a backward seek
219  *
220  * pos
221  * +-------------+----------------------------------------------+
222  * output file: | | |
223  * +-------------+----------------------------------------------+
224  *
225  */
226  unsigned char *buffer; /**< Start of the buffer. */
227  int buffer_size; /**< Maximum buffer size */
228  unsigned char *buf_ptr; /**< Current position in the buffer */
229  unsigned char *buf_end; /**< End of the data, may be less than
230  buffer+buffer_size if the read function returned
231  less data than requested, e.g. for streams where
232  no more data has been received yet. */
233  void *opaque; /**< A private pointer, passed to the read/write/seek/...
234  functions. */
235  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
236  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
237  int64_t (*seek)(void *opaque, int64_t offset, int whence);
238  int64_t pos; /**< position in the file of the current buffer */
239  int eof_reached; /**< true if was unable to read due to error or eof */
240  int error; /**< contains the error code or 0 if no error happened */
241  int write_flag; /**< true if open for writing */
243  int min_packet_size; /**< Try to buffer at least this amount of data
244  before flushing it. */
245  unsigned long checksum;
246  unsigned char *checksum_ptr;
247  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
248  /**
249  * Pause or resume playback for network streaming protocols - e.g. MMS.
250  */
251  int (*read_pause)(void *opaque, int pause);
252  /**
253  * Seek to a given timestamp in stream with the specified stream_index.
254  * Needed for some network streaming protocols which don't support seeking
255  * to byte position.
256  */
257  int64_t (*read_seek)(void *opaque, int stream_index,
258  int64_t timestamp, int flags);
259  /**
260  * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
261  */
262  int seekable;
263 
264  /**
265  * avio_read and avio_write should if possible be satisfied directly
266  * instead of going through a buffer, and avio_seek will always
267  * call the underlying seek function directly.
268  */
269  int direct;
270 
271  /**
272  * ',' separated list of allowed protocols.
273  */
274  const char *protocol_whitelist;
275 
276  /**
277  * ',' separated list of disallowed protocols.
278  */
279  const char *protocol_blacklist;
280 
281  /**
282  * A callback that is used instead of write_packet.
283  */
284  int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size,
285  enum AVIODataMarkerType type, int64_t time);
286  /**
287  * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
288  * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
289  * small chunks of data returned from the callback).
290  */
292 
293 #if FF_API_AVIOCONTEXT_WRITTEN
294  /**
295  * @deprecated field utilized privately by libavformat. For a public
296  * statistic of how many bytes were written out, see
297  * AVIOContext::bytes_written.
298  */
300  int64_t written;
301 #endif
302 
303  /**
304  * Maximum reached position before a backward seek in the write buffer,
305  * used keeping track of already written data for a later flush.
306  */
307  unsigned char *buf_ptr_max;
308 
309  /**
310  * Read-only statistic of bytes read for this AVIOContext.
311  */
312  int64_t bytes_read;
313 
314  /**
315  * Read-only statistic of bytes written for this AVIOContext.
316  */
317  int64_t bytes_written;
318 } AVIOContext;
319 
320 /**
321  * Return the name of the protocol that will handle the passed URL.
322  *
323  * NULL is returned if no protocol could be found for the given URL.
324  *
325  * @return Name of the protocol or NULL.
326  */
327 const char *avio_find_protocol_name(const char *url);
328 
329 /**
330  * Return AVIO_FLAG_* access flags corresponding to the access permissions
331  * of the resource in url, or a negative value corresponding to an
332  * AVERROR code in case of failure. The returned access flags are
333  * masked by the value in flags.
334  *
335  * @note This function is intrinsically unsafe, in the sense that the
336  * checked resource may change its existence or permission status from
337  * one call to another. Thus you should not trust the returned value,
338  * unless you are sure that no other processes are accessing the
339  * checked resource.
340  */
341 int avio_check(const char *url, int flags);
342 
343 /**
344  * Open directory for reading.
345  *
346  * @param s directory read context. Pointer to a NULL pointer must be passed.
347  * @param url directory to be listed.
348  * @param options A dictionary filled with protocol-private options. On return
349  * this parameter will be destroyed and replaced with a dictionary
350  * containing options that were not found. May be NULL.
351  * @return >=0 on success or negative on error.
352  */
353 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
354 
355 /**
356  * Get next directory entry.
357  *
358  * Returned entry must be freed with avio_free_directory_entry(). In particular
359  * it may outlive AVIODirContext.
360  *
361  * @param s directory read context.
362  * @param[out] next next entry or NULL when no more entries.
363  * @return >=0 on success or negative on error. End of list is not considered an
364  * error.
365  */
367 
368 /**
369  * Close directory.
370  *
371  * @note Entries created using avio_read_dir() are not deleted and must be
372  * freeded with avio_free_directory_entry().
373  *
374  * @param s directory read context.
375  * @return >=0 on success or negative on error.
376  */
378 
379 /**
380  * Free entry allocated by avio_read_dir().
381  *
382  * @param entry entry to be freed.
383  */
385 
386 /**
387  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
388  * freed with avio_context_free().
389  *
390  * @param buffer Memory block for input/output operations via AVIOContext.
391  * The buffer must be allocated with av_malloc() and friends.
392  * It may be freed and replaced with a new buffer by libavformat.
393  * AVIOContext.buffer holds the buffer currently in use,
394  * which must be later freed with av_free().
395  * @param buffer_size The buffer size is very important for performance.
396  * For protocols with fixed blocksize it should be set to this blocksize.
397  * For others a typical size is a cache page, e.g. 4kb.
398  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
399  * @param opaque An opaque pointer to user-specific data.
400  * @param read_packet A function for refilling the buffer, may be NULL.
401  * For stream protocols, must never return 0 but rather
402  * a proper AVERROR code.
403  * @param write_packet A function for writing the buffer contents, may be NULL.
404  * The function may not change the input buffers content.
405  * @param seek A function for seeking to specified byte position, may be NULL.
406  *
407  * @return Allocated AVIOContext or NULL on failure.
408  */
410  unsigned char *buffer,
411  int buffer_size,
412  int write_flag,
413  void *opaque,
414  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
415  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
416  int64_t (*seek)(void *opaque, int64_t offset, int whence));
417 
418 /**
419  * Free the supplied IO context and everything associated with it.
420  *
421  * @param s Double pointer to the IO context. This function will write NULL
422  * into s.
423  */
425 
426 void avio_w8(AVIOContext *s, int b);
427 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
428 void avio_wl64(AVIOContext *s, uint64_t val);
429 void avio_wb64(AVIOContext *s, uint64_t val);
430 void avio_wl32(AVIOContext *s, unsigned int val);
431 void avio_wb32(AVIOContext *s, unsigned int val);
432 void avio_wl24(AVIOContext *s, unsigned int val);
433 void avio_wb24(AVIOContext *s, unsigned int val);
434 void avio_wl16(AVIOContext *s, unsigned int val);
435 void avio_wb16(AVIOContext *s, unsigned int val);
436 
437 /**
438  * Write a NULL-terminated string.
439  * @return number of bytes written.
440  */
441 int avio_put_str(AVIOContext *s, const char *str);
442 
443 /**
444  * Convert an UTF-8 string to UTF-16LE and write it.
445  * @param s the AVIOContext
446  * @param str NULL-terminated UTF-8 string
447  *
448  * @return number of bytes written.
449  */
450 int avio_put_str16le(AVIOContext *s, const char *str);
451 
452 /**
453  * Convert an UTF-8 string to UTF-16BE and write it.
454  * @param s the AVIOContext
455  * @param str NULL-terminated UTF-8 string
456  *
457  * @return number of bytes written.
458  */
459 int avio_put_str16be(AVIOContext *s, const char *str);
460 
461 /**
462  * Mark the written bytestream as a specific type.
463  *
464  * Zero-length ranges are omitted from the output.
465  *
466  * @param time the stream time the current bytestream pos corresponds to
467  * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
468  * applicable
469  * @param type the kind of data written starting at the current pos
470  */
471 void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
472 
473 /**
474  * ORing this as the "whence" parameter to a seek function causes it to
475  * return the filesize without seeking anywhere. Supporting this is optional.
476  * If it is not supported then the seek function will return <0.
477  */
478 #define AVSEEK_SIZE 0x10000
479 
480 /**
481  * Passing this flag as the "whence" parameter to a seek function causes it to
482  * seek by any means (like reopening and linear reading) or other normally unreasonable
483  * means that can be extremely slow.
484  * This may be ignored by the seek code.
485  */
486 #define AVSEEK_FORCE 0x20000
487 
488 /**
489  * fseek() equivalent for AVIOContext.
490  * @return new position or AVERROR.
491  */
492 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
493 
494 /**
495  * Skip given number of bytes forward
496  * @return new position or AVERROR.
497  */
498 int64_t avio_skip(AVIOContext *s, int64_t offset);
499 
500 /**
501  * ftell() equivalent for AVIOContext.
502  * @return position or AVERROR.
503  */
505 {
506  return avio_seek(s, 0, SEEK_CUR);
507 }
508 
509 /**
510  * Get the filesize.
511  * @return filesize or AVERROR
512  */
513 int64_t avio_size(AVIOContext *s);
514 
515 /**
516  * Similar to feof() but also returns nonzero on read errors.
517  * @return non zero if and only if at end of file or a read error happened when reading.
518  */
520 
521 /**
522  * Writes a formatted string to the context.
523  * @return number of bytes written, < 0 on error.
524  */
525 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
526 
527 /**
528  * Write a NULL terminated array of strings to the context.
529  * Usually you don't need to use this function directly but its macro wrapper,
530  * avio_print.
531  */
532 void avio_print_string_array(AVIOContext *s, const char *strings[]);
533 
534 /**
535  * Write strings (const char *) to the context.
536  * This is a convenience macro around avio_print_string_array and it
537  * automatically creates the string array from the variable argument list.
538  * For simple string concatenations this function is more performant than using
539  * avio_printf since it does not need a temporary buffer.
540  */
541 #define avio_print(s, ...) \
542  avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
543 
544 /**
545  * Force flushing of buffered data.
546  *
547  * For write streams, force the buffered data to be immediately written to the output,
548  * without to wait to fill the internal buffer.
549  *
550  * For read streams, discard all currently buffered data, and advance the
551  * reported file position to that of the underlying stream. This does not
552  * read new data, and does not perform any seeks.
553  */
555 
556 /**
557  * Read size bytes from AVIOContext into buf.
558  * @return number of bytes read or AVERROR
559  */
560 int avio_read(AVIOContext *s, unsigned char *buf, int size);
561 
562 /**
563  * Read size bytes from AVIOContext into buf. Unlike avio_read(), this is allowed
564  * to read fewer bytes than requested. The missing bytes can be read in the next
565  * call. This always tries to read at least 1 byte.
566  * Useful to reduce latency in certain cases.
567  * @return number of bytes read or AVERROR
568  */
569 int avio_read_partial(AVIOContext *s, unsigned char *buf, int size);
570 
571 /**
572  * @name Functions for reading from AVIOContext
573  * @{
574  *
575  * @note return 0 if EOF, so you cannot use it if EOF handling is
576  * necessary
577  */
579 unsigned int avio_rl16(AVIOContext *s);
580 unsigned int avio_rl24(AVIOContext *s);
581 unsigned int avio_rl32(AVIOContext *s);
582 uint64_t avio_rl64(AVIOContext *s);
583 unsigned int avio_rb16(AVIOContext *s);
584 unsigned int avio_rb24(AVIOContext *s);
585 unsigned int avio_rb32(AVIOContext *s);
586 uint64_t avio_rb64(AVIOContext *s);
587 /**
588  * @}
589  */
590 
591 /**
592  * Read a string from pb into buf. The reading will terminate when either
593  * a NULL character was encountered, maxlen bytes have been read, or nothing
594  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
595  * will be truncated if buf is too small.
596  * Note that the string is not interpreted or validated in any way, it
597  * might get truncated in the middle of a sequence for multi-byte encodings.
598  *
599  * @return number of bytes read (is always <= maxlen).
600  * If reading ends on EOF or error, the return value will be one more than
601  * bytes actually read.
602  */
603 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
604 
605 /**
606  * Read a UTF-16 string from pb and convert it to UTF-8.
607  * The reading will terminate when either a null or invalid character was
608  * encountered or maxlen bytes have been read.
609  * @return number of bytes read (is always <= maxlen)
610  */
611 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
612 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
613 
614 
615 /**
616  * @name URL open modes
617  * The flags argument to avio_open must be one of the following
618  * constants, optionally ORed with other flags.
619  * @{
620  */
621 #define AVIO_FLAG_READ 1 /**< read-only */
622 #define AVIO_FLAG_WRITE 2 /**< write-only */
623 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
624 /**
625  * @}
626  */
627 
628 /**
629  * Use non-blocking mode.
630  * If this flag is set, operations on the context will return
631  * AVERROR(EAGAIN) if they can not be performed immediately.
632  * If this flag is not set, operations on the context will never return
633  * AVERROR(EAGAIN).
634  * Note that this flag does not affect the opening/connecting of the
635  * context. Connecting a protocol will always block if necessary (e.g. on
636  * network protocols) but never hang (e.g. on busy devices).
637  * Warning: non-blocking protocols is work-in-progress; this flag may be
638  * silently ignored.
639  */
640 #define AVIO_FLAG_NONBLOCK 8
641 
642 /**
643  * Use direct mode.
644  * avio_read and avio_write should if possible be satisfied directly
645  * instead of going through a buffer, and avio_seek will always
646  * call the underlying seek function directly.
647  */
648 #define AVIO_FLAG_DIRECT 0x8000
649 
650 /**
651  * Create and initialize a AVIOContext for accessing the
652  * resource indicated by url.
653  * @note When the resource indicated by url has been opened in
654  * read+write mode, the AVIOContext can be used only for writing.
655  *
656  * @param s Used to return the pointer to the created AVIOContext.
657  * In case of failure the pointed to value is set to NULL.
658  * @param url resource to access
659  * @param flags flags which control how the resource indicated by url
660  * is to be opened
661  * @return >= 0 in case of success, a negative value corresponding to an
662  * AVERROR code in case of failure
663  */
664 int avio_open(AVIOContext **s, const char *url, int flags);
665 
666 /**
667  * Create and initialize a AVIOContext for accessing the
668  * resource indicated by url.
669  * @note When the resource indicated by url has been opened in
670  * read+write mode, the AVIOContext can be used only for writing.
671  *
672  * @param s Used to return the pointer to the created AVIOContext.
673  * In case of failure the pointed to value is set to NULL.
674  * @param url resource to access
675  * @param flags flags which control how the resource indicated by url
676  * is to be opened
677  * @param int_cb an interrupt callback to be used at the protocols level
678  * @param options A dictionary filled with protocol-private options. On return
679  * this parameter will be destroyed and replaced with a dict containing options
680  * that were not found. May be NULL.
681  * @return >= 0 in case of success, a negative value corresponding to an
682  * AVERROR code in case of failure
683  */
684 int avio_open2(AVIOContext **s, const char *url, int flags,
685  const AVIOInterruptCB *int_cb, AVDictionary **options);
686 
687 /**
688  * Close the resource accessed by the AVIOContext s and free it.
689  * This function can only be used if s was opened by avio_open().
690  *
691  * The internal buffer is automatically flushed before closing the
692  * resource.
693  *
694  * @return 0 on success, an AVERROR < 0 on error.
695  * @see avio_closep
696  */
698 
699 /**
700  * Close the resource accessed by the AVIOContext *s, free it
701  * and set the pointer pointing to it to NULL.
702  * This function can only be used if s was opened by avio_open().
703  *
704  * The internal buffer is automatically flushed before closing the
705  * resource.
706  *
707  * @return 0 on success, an AVERROR < 0 on error.
708  * @see avio_close
709  */
711 
712 
713 /**
714  * Open a write only memory stream.
715  *
716  * @param s new IO context
717  * @return zero if no error.
718  */
720 
721 /**
722  * Return the written size and a pointer to the buffer.
723  * The AVIOContext stream is left intact.
724  * The buffer must NOT be freed.
725  * No padding is added to the buffer.
726  *
727  * @param s IO context
728  * @param pbuffer pointer to a byte buffer
729  * @return the length of the byte buffer
730  */
731 int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
732 
733 /**
734  * Return the written size and a pointer to the buffer. The buffer
735  * must be freed with av_free().
736  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
737  *
738  * @param s IO context
739  * @param pbuffer pointer to a byte buffer
740  * @return the length of the byte buffer
741  */
742 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
743 
744 /**
745  * Iterate through names of available protocols.
746  *
747  * @param opaque A private pointer representing current protocol.
748  * It must be a pointer to NULL on first iteration and will
749  * be updated by successive calls to avio_enum_protocols.
750  * @param output If set to 1, iterate over output protocols,
751  * otherwise over input protocols.
752  *
753  * @return A static string containing the name of current protocol or NULL
754  */
755 const char *avio_enum_protocols(void **opaque, int output);
756 
757 /**
758  * Get AVClass by names of available protocols.
759  *
760  * @return A AVClass of input protocol name or NULL
761  */
762 const AVClass *avio_protocol_get_class(const char *name);
763 
764 /**
765  * Pause and resume playing - only meaningful if using a network streaming
766  * protocol (e.g. MMS).
767  *
768  * @param h IO context from which to call the read_pause function pointer
769  * @param pause 1 for pause, 0 for resume
770  */
771 int avio_pause(AVIOContext *h, int pause);
772 
773 /**
774  * Seek to a given timestamp relative to some component stream.
775  * Only meaningful if using a network streaming protocol (e.g. MMS.).
776  *
777  * @param h IO context from which to call the seek function pointers
778  * @param stream_index The stream index that the timestamp is relative to.
779  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
780  * units from the beginning of the presentation.
781  * If a stream_index >= 0 is used and the protocol does not support
782  * seeking based on component streams, the call will fail.
783  * @param timestamp timestamp in AVStream.time_base units
784  * or if there is no stream specified then in AV_TIME_BASE units.
785  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
786  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
787  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
788  * fail if used and not supported.
789  * @return >= 0 on success
790  * @see AVInputFormat::read_seek
791  */
792 int64_t avio_seek_time(AVIOContext *h, int stream_index,
793  int64_t timestamp, int flags);
794 
795 /* Avoid a warning. The header can not be included because it breaks c++. */
796 struct AVBPrint;
797 
798 /**
799  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
800  *
801  * @return 0 for success (max_size bytes read or EOF reached), negative error
802  * code otherwise
803  */
804 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
805 
806 /**
807  * Accept and allocate a client context on a server context.
808  * @param s the server context
809  * @param c the client context, must be unallocated
810  * @return >= 0 on success or a negative value corresponding
811  * to an AVERROR on failure
812  */
814 
815 /**
816  * Perform one step of the protocol handshake to accept a new client.
817  * This function must be called on a client returned by avio_accept() before
818  * using it as a read/write context.
819  * It is separate from avio_accept() because it may block.
820  * A step of the handshake is defined by places where the application may
821  * decide to change the proceedings.
822  * For example, on a protocol with a request header and a reply header, each
823  * one can constitute a step because the application may use the parameters
824  * from the request to change parameters in the reply; or each individual
825  * chunk of the request can constitute a step.
826  * If the handshake is already finished, avio_handshake() does nothing and
827  * returns 0 immediately.
828  *
829  * @param c the client context to perform the handshake on
830  * @return 0 on a complete and successful handshake
831  * > 0 if the handshake progressed, but is not complete
832  * < 0 for an AVERROR code
833  */
835 #endif /* AVFORMAT_AVIO_H */
#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)
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:111
@ 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:128
@ AVIO_DATA_MARKER_TRAILER
Trailer data, which doesn't contain actual content, but only for finalizing the output file.
Definition: avio.h:140
@ AVIO_DATA_MARKER_HEADER
Header data; this needs to be present for the stream to be decodeable.
Definition: avio.h:115
@ AVIO_DATA_MARKER_UNKNOWN
This is any, unlabelled data.
Definition: avio.h:135
@ AVIO_DATA_MARKER_FLUSH_POINT
A point in the output bytestream where the underlying AVIOContext might flush the buffer depending on...
Definition: avio.h:146
@ AVIO_DATA_MARKER_SYNC_POINT
A point in the output bytestream where a decoder can start decoding (i.e.
Definition: avio.h:122
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:504
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:66
@ AVIO_ENTRY_UNKNOWN
Definition: avio.h:67
@ AVIO_ENTRY_NAMED_PIPE
Definition: avio.h:71
@ AVIO_ENTRY_WORKGROUP
Definition: avio.h:77
@ AVIO_ENTRY_SERVER
Definition: avio.h:75
@ AVIO_ENTRY_SHARE
Definition: avio.h:76
@ AVIO_ENTRY_BLOCK_DEVICE
Definition: avio.h:68
@ AVIO_ENTRY_SYMBOLIC_LINK
Definition: avio.h:72
@ AVIO_ENTRY_DIRECTORY
Definition: avio.h:70
@ AVIO_ENTRY_CHARACTER_DEVICE
Definition: avio.h:69
@ AVIO_ENTRY_FILE
Definition: avio.h:74
@ AVIO_ENTRY_SOCKET
Definition: avio.h:73
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
common internal and external API header
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:161
int buffer_size
Maximum buffer size.
Definition: avio.h:227
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:229
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:262
unsigned char * checksum_ptr
Definition: avio.h:246
const AVClass * av_class
A class for private options.
Definition: avio.h:174
int64_t bytes_read
Read-only statistic of bytes read for this AVIOContext.
Definition: avio.h:312
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:228
int ignore_boundary_point
If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,...
Definition: avio.h:291
int min_packet_size
Try to buffer at least this amount of data before flushing it.
Definition: avio.h:243
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:237
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:307
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:274
int64_t pos
position in the file of the current buffer
Definition: avio.h:238
unsigned long(* update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size)
Definition: avio.h:247
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:279
int64_t bytes_written
Read-only statistic of bytes written for this AVIOContext.
Definition: avio.h:317
unsigned char * buffer
Start of the buffer.
Definition: avio.h:226
unsigned long checksum
Definition: avio.h:245
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:235
int eof_reached
true if was unable to read due to error or eof
Definition: avio.h:239
int write_flag
true if open for writing
Definition: avio.h:241
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:257
int max_packet_size
Definition: avio.h:242
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:251
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:284
int direct
avio_read and avio_write should if possible be satisfied directly instead of going through a buffer,...
Definition: avio.h:269
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:233
int(* write_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:236
int error
contains the error code or 0 if no error happened
Definition: avio.h:240
struct URLContext * url_context
Definition: avio.h:104
Describes single entry of the directory.
Definition: avio.h:86
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:98
int type
Type of the entry.
Definition: avio.h:88
int64_t access_timestamp
Time of last access in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:94
int64_t status_change_timestamp
Time of last status change in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:96
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:91
int64_t group_id
Group ID of owner, -1 if unknown.
Definition: avio.h:99
char * name
Filename.
Definition: avio.h:87
int utf8
Set to 1 when name is encoded with UTF-8, 0 otherwise.
Definition: avio.h:89
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:92
int64_t filemode
Unix file mode, -1 if unknown.
Definition: avio.h:100
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
void * opaque
Definition: avio.h:60
int(* callback)(void *)
Definition: avio.h:59