FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
avio.h
Go to the documentation of this file.
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 #define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
38 
39 /**
40  * Callback for checking whether to abort blocking functions.
41  * AVERROR_EXIT is returned in this case by the interrupted
42  * function. During blocking operations, callback is called with
43  * opaque as parameter. If the callback returns 1, the
44  * blocking operation will be aborted.
45  *
46  * No members can be added to this struct without a major bump, if
47  * new elements have been added after this struct in AVFormatContext
48  * or AVIOContext.
49  */
50 typedef struct AVIOInterruptCB {
51  int (*callback)(void*);
52  void *opaque;
54 
55 /**
56  * Directory entry types.
57  */
70 };
71 
72 /**
73  * Describes single entry of the directory.
74  *
75  * Only name and type fields are guaranteed be set.
76  * Rest of fields are protocol or/and platform dependent and might be unknown.
77  */
78 typedef struct AVIODirEntry {
79  char *name; /**< Filename */
80  int type; /**< Type of the entry */
81  int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise.
82  Name can be encoded with UTF-8 even though 0 is set. */
83  int64_t size; /**< File size in bytes, -1 if unknown. */
84  int64_t modification_timestamp; /**< Time of last modification in microseconds since unix
85  epoch, -1 if unknown. */
86  int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch,
87  -1 if unknown. */
88  int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix
89  epoch, -1 if unknown. */
90  int64_t user_id; /**< User ID of owner, -1 if unknown. */
91  int64_t group_id; /**< Group ID of owner, -1 if unknown. */
92  int64_t filemode; /**< Unix file mode, -1 if unknown. */
93 } AVIODirEntry;
94 
95 typedef struct AVIODirContext {
98 
99 /**
100  * Bytestream IO Context.
101  * New fields can be added to the end with minor version bumps.
102  * Removal, reordering and changes to existing fields require a major
103  * version bump.
104  * sizeof(AVIOContext) must not be used outside libav*.
105  *
106  * @note None of the function pointers in AVIOContext should be called
107  * directly, they should only be set by the client application
108  * when implementing custom I/O. Normally these are set to the
109  * function pointers specified in avio_alloc_context()
110  */
111 typedef struct AVIOContext {
112  /**
113  * A class for private options.
114  *
115  * If this AVIOContext is created by avio_open2(), av_class is set and
116  * passes the options down to protocols.
117  *
118  * If this AVIOContext is manually allocated, then av_class may be set by
119  * the caller.
120  *
121  * warning -- this field can be NULL, be sure to not pass this AVIOContext
122  * to any av_opt_* functions in that case.
123  */
125 
126  /*
127  * The following shows the relationship between buffer, buf_ptr, buf_end, buf_size,
128  * and pos, when reading and when writing (since AVIOContext is used for both):
129  *
130  **********************************************************************************
131  * READING
132  **********************************************************************************
133  *
134  * | buffer_size |
135  * |---------------------------------------|
136  * | |
137  *
138  * buffer buf_ptr buf_end
139  * +---------------+-----------------------+
140  * |/ / / / / / / /|/ / / / / / /| |
141  * read buffer: |/ / consumed / | to be read /| |
142  * |/ / / / / / / /|/ / / / / / /| |
143  * +---------------+-----------------------+
144  *
145  * pos
146  * +-------------------------------------------+-----------------+
147  * input file: | | |
148  * +-------------------------------------------+-----------------+
149  *
150  *
151  **********************************************************************************
152  * WRITING
153  **********************************************************************************
154  *
155  * | buffer_size |
156  * |-------------------------------|
157  * | |
158  *
159  * buffer buf_ptr buf_end
160  * +-------------------+-----------+
161  * |/ / / / / / / / / /| |
162  * write buffer: | / to be flushed / | |
163  * |/ / / / / / / / / /| |
164  * +-------------------+-----------+
165  *
166  * pos
167  * +--------------------------+-----------------------------------+
168  * output file: | | |
169  * +--------------------------+-----------------------------------+
170  *
171  */
172  unsigned char *buffer; /**< Start of the buffer. */
173  int buffer_size; /**< Maximum buffer size */
174  unsigned char *buf_ptr; /**< Current position in the buffer */
175  unsigned char *buf_end; /**< End of the data, may be less than
176  buffer+buffer_size if the read function returned
177  less data than requested, e.g. for streams where
178  no more data has been received yet. */
179  void *opaque; /**< A private pointer, passed to the read/write/seek/...
180  functions. */
181  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
182  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
183  int64_t (*seek)(void *opaque, int64_t offset, int whence);
184  int64_t pos; /**< position in the file of the current buffer */
185  int must_flush; /**< true if the next seek should flush */
186  int eof_reached; /**< true if eof reached */
187  int write_flag; /**< true if open for writing */
189  unsigned long checksum;
190  unsigned char *checksum_ptr;
191  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
192  int error; /**< contains the error code or 0 if no error happened */
193  /**
194  * Pause or resume playback for network streaming protocols - e.g. MMS.
195  */
196  int (*read_pause)(void *opaque, int pause);
197  /**
198  * Seek to a given timestamp in stream with the specified stream_index.
199  * Needed for some network streaming protocols which don't support seeking
200  * to byte position.
201  */
202  int64_t (*read_seek)(void *opaque, int stream_index,
203  int64_t timestamp, int flags);
204  /**
205  * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
206  */
207  int seekable;
208 
209  /**
210  * max filesize, used to limit allocations
211  * This field is internal to libavformat and access from outside is not allowed.
212  */
213  int64_t maxsize;
214 
215  /**
216  * avio_read and avio_write should if possible be satisfied directly
217  * instead of going through a buffer, and avio_seek will always
218  * call the underlying seek function directly.
219  */
220  int direct;
221 
222  /**
223  * Bytes read statistic
224  * This field is internal to libavformat and access from outside is not allowed.
225  */
226  int64_t bytes_read;
227 
228  /**
229  * seek statistic
230  * This field is internal to libavformat and access from outside is not allowed.
231  */
233 
234  /**
235  * writeout statistic
236  * This field is internal to libavformat and access from outside is not allowed.
237  */
239 
240  /**
241  * Original buffer size
242  * used internally after probing and ensure seekback to reset the buffer size
243  * This field is internal to libavformat and access from outside is not allowed.
244  */
246 
247  /**
248  * Threshold to favor readahead over seek.
249  * This is current internal only, do not use from outside.
250  */
252 
253  /**
254  * ',' separated list of allowed protocols.
255  */
256  const char *protocol_whitelist;
257 
258  /**
259  * ',' separated list of disallowed protocols.
260  */
261  const char *protocol_blacklist;
262 } AVIOContext;
263 
264 /* unbuffered I/O */
265 
266 /**
267  * Return the name of the protocol that will handle the passed URL.
268  *
269  * NULL is returned if no protocol could be found for the given URL.
270  *
271  * @return Name of the protocol or NULL.
272  */
273 const char *avio_find_protocol_name(const char *url);
274 
275 /**
276  * Return AVIO_FLAG_* access flags corresponding to the access permissions
277  * of the resource in url, or a negative value corresponding to an
278  * AVERROR code in case of failure. The returned access flags are
279  * masked by the value in flags.
280  *
281  * @note This function is intrinsically unsafe, in the sense that the
282  * checked resource may change its existence or permission status from
283  * one call to another. Thus you should not trust the returned value,
284  * unless you are sure that no other processes are accessing the
285  * checked resource.
286  */
287 int avio_check(const char *url, int flags);
288 
289 /**
290  * Move or rename a resource.
291  *
292  * @note url_src and url_dst should share the same protocol and authority.
293  *
294  * @param url_src url to resource to be moved
295  * @param url_dst new url to resource if the operation succeeded
296  * @return >=0 on success or negative on error.
297  */
298 int avpriv_io_move(const char *url_src, const char *url_dst);
299 
300 /**
301  * Delete a resource.
302  *
303  * @param url resource to be deleted.
304  * @return >=0 on success or negative on error.
305  */
306 int avpriv_io_delete(const char *url);
307 
308 /**
309  * Open directory for reading.
310  *
311  * @param s directory read context. Pointer to a NULL pointer must be passed.
312  * @param url directory to be listed.
313  * @param options A dictionary filled with protocol-private options. On return
314  * this parameter will be destroyed and replaced with a dictionary
315  * containing options that were not found. May be NULL.
316  * @return >=0 on success or negative on error.
317  */
318 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
319 
320 /**
321  * Get next directory entry.
322  *
323  * Returned entry must be freed with avio_free_directory_entry(). In particular
324  * it may outlive AVIODirContext.
325  *
326  * @param s directory read context.
327  * @param[out] next next entry or NULL when no more entries.
328  * @return >=0 on success or negative on error. End of list is not considered an
329  * error.
330  */
332 
333 /**
334  * Close directory.
335  *
336  * @note Entries created using avio_read_dir() are not deleted and must be
337  * freeded with avio_free_directory_entry().
338  *
339  * @param s directory read context.
340  * @return >=0 on success or negative on error.
341  */
343 
344 /**
345  * Free entry allocated by avio_read_dir().
346  *
347  * @param entry entry to be freed.
348  */
350 
351 /**
352  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
353  * freed with av_free().
354  *
355  * @param buffer Memory block for input/output operations via AVIOContext.
356  * The buffer must be allocated with av_malloc() and friends.
357  * It may be freed and replaced with a new buffer by libavformat.
358  * AVIOContext.buffer holds the buffer currently in use,
359  * which must be later freed with av_free().
360  * @param buffer_size The buffer size is very important for performance.
361  * For protocols with fixed blocksize it should be set to this blocksize.
362  * For others a typical size is a cache page, e.g. 4kb.
363  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
364  * @param opaque An opaque pointer to user-specific data.
365  * @param read_packet A function for refilling the buffer, may be NULL.
366  * @param write_packet A function for writing the buffer contents, may be NULL.
367  * The function may not change the input buffers content.
368  * @param seek A function for seeking to specified byte position, may be NULL.
369  *
370  * @return Allocated AVIOContext or NULL on failure.
371  */
373  unsigned char *buffer,
374  int buffer_size,
375  int write_flag,
376  void *opaque,
377  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
378  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
379  int64_t (*seek)(void *opaque, int64_t offset, int whence));
380 
381 void avio_w8(AVIOContext *s, int b);
382 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
383 void avio_wl64(AVIOContext *s, uint64_t val);
384 void avio_wb64(AVIOContext *s, uint64_t val);
385 void avio_wl32(AVIOContext *s, unsigned int val);
386 void avio_wb32(AVIOContext *s, unsigned int val);
387 void avio_wl24(AVIOContext *s, unsigned int val);
388 void avio_wb24(AVIOContext *s, unsigned int val);
389 void avio_wl16(AVIOContext *s, unsigned int val);
390 void avio_wb16(AVIOContext *s, unsigned int val);
391 
392 /**
393  * Write a NULL-terminated string.
394  * @return number of bytes written.
395  */
396 int avio_put_str(AVIOContext *s, const char *str);
397 
398 /**
399  * Convert an UTF-8 string to UTF-16LE and write it.
400  * @param s the AVIOContext
401  * @param str NULL-terminated UTF-8 string
402  *
403  * @return number of bytes written.
404  */
405 int avio_put_str16le(AVIOContext *s, const char *str);
406 
407 /**
408  * Convert an UTF-8 string to UTF-16BE and write it.
409  * @param s the AVIOContext
410  * @param str NULL-terminated UTF-8 string
411  *
412  * @return number of bytes written.
413  */
414 int avio_put_str16be(AVIOContext *s, const char *str);
415 
416 /**
417  * Passing this as the "whence" parameter to a seek function causes it to
418  * return the filesize without seeking anywhere. Supporting this is optional.
419  * If it is not supported then the seek function will return <0.
420  */
421 #define AVSEEK_SIZE 0x10000
422 
423 /**
424  * Oring this flag as into the "whence" parameter to a seek function causes it to
425  * seek by any means (like reopening and linear reading) or other normally unreasonable
426  * means that can be extremely slow.
427  * This may be ignored by the seek code.
428  */
429 #define AVSEEK_FORCE 0x20000
430 
431 /**
432  * fseek() equivalent for AVIOContext.
433  * @return new position or AVERROR.
434  */
435 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
436 
437 /**
438  * Skip given number of bytes forward
439  * @return new position or AVERROR.
440  */
441 int64_t avio_skip(AVIOContext *s, int64_t offset);
442 
443 /**
444  * ftell() equivalent for AVIOContext.
445  * @return position or AVERROR.
446  */
448 {
449  return avio_seek(s, 0, SEEK_CUR);
450 }
451 
452 /**
453  * Get the filesize.
454  * @return filesize or AVERROR
455  */
456 int64_t avio_size(AVIOContext *s);
457 
458 /**
459  * feof() equivalent for AVIOContext.
460  * @return non zero if and only if end of file
461  */
462 int avio_feof(AVIOContext *s);
463 #if FF_API_URL_FEOF
464 /**
465  * @deprecated use avio_feof()
466  */
468 int url_feof(AVIOContext *s);
469 #endif
470 
471 /** @warning Writes up to 4 KiB per call */
472 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
473 
474 /**
475  * Force flushing of buffered data.
476  *
477  * For write streams, force the buffered data to be immediately written to the output,
478  * without to wait to fill the internal buffer.
479  *
480  * For read streams, discard all currently buffered data, and advance the
481  * reported file position to that of the underlying stream. This does not
482  * read new data, and does not perform any seeks.
483  */
484 void avio_flush(AVIOContext *s);
485 
486 /**
487  * Read size bytes from AVIOContext into buf.
488  * @return number of bytes read or AVERROR
489  */
490 int avio_read(AVIOContext *s, unsigned char *buf, int size);
491 
492 /**
493  * @name Functions for reading from AVIOContext
494  * @{
495  *
496  * @note return 0 if EOF, so you cannot use it if EOF handling is
497  * necessary
498  */
499 int avio_r8 (AVIOContext *s);
500 unsigned int avio_rl16(AVIOContext *s);
501 unsigned int avio_rl24(AVIOContext *s);
502 unsigned int avio_rl32(AVIOContext *s);
503 uint64_t avio_rl64(AVIOContext *s);
504 unsigned int avio_rb16(AVIOContext *s);
505 unsigned int avio_rb24(AVIOContext *s);
506 unsigned int avio_rb32(AVIOContext *s);
507 uint64_t avio_rb64(AVIOContext *s);
508 /**
509  * @}
510  */
511 
512 /**
513  * Read a string from pb into buf. The reading will terminate when either
514  * a NULL character was encountered, maxlen bytes have been read, or nothing
515  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
516  * will be truncated if buf is too small.
517  * Note that the string is not interpreted or validated in any way, it
518  * might get truncated in the middle of a sequence for multi-byte encodings.
519  *
520  * @return number of bytes read (is always <= maxlen).
521  * If reading ends on EOF or error, the return value will be one more than
522  * bytes actually read.
523  */
524 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
525 
526 /**
527  * Read a UTF-16 string from pb and convert it to UTF-8.
528  * The reading will terminate when either a null or invalid character was
529  * encountered or maxlen bytes have been read.
530  * @return number of bytes read (is always <= maxlen)
531  */
532 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
533 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
534 
535 
536 /**
537  * @name URL open modes
538  * The flags argument to avio_open must be one of the following
539  * constants, optionally ORed with other flags.
540  * @{
541  */
542 #define AVIO_FLAG_READ 1 /**< read-only */
543 #define AVIO_FLAG_WRITE 2 /**< write-only */
544 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
545 /**
546  * @}
547  */
548 
549 /**
550  * Use non-blocking mode.
551  * If this flag is set, operations on the context will return
552  * AVERROR(EAGAIN) if they can not be performed immediately.
553  * If this flag is not set, operations on the context will never return
554  * AVERROR(EAGAIN).
555  * Note that this flag does not affect the opening/connecting of the
556  * context. Connecting a protocol will always block if necessary (e.g. on
557  * network protocols) but never hang (e.g. on busy devices).
558  * Warning: non-blocking protocols is work-in-progress; this flag may be
559  * silently ignored.
560  */
561 #define AVIO_FLAG_NONBLOCK 8
562 
563 /**
564  * Use direct mode.
565  * avio_read and avio_write should if possible be satisfied directly
566  * instead of going through a buffer, and avio_seek will always
567  * call the underlying seek function directly.
568  */
569 #define AVIO_FLAG_DIRECT 0x8000
570 
571 /**
572  * Create and initialize a AVIOContext for accessing the
573  * resource indicated by url.
574  * @note When the resource indicated by url has been opened in
575  * read+write mode, the AVIOContext can be used only for writing.
576  *
577  * @param s Used to return the pointer to the created AVIOContext.
578  * In case of failure the pointed to value is set to NULL.
579  * @param url resource to access
580  * @param flags flags which control how the resource indicated by url
581  * is to be opened
582  * @return >= 0 in case of success, a negative value corresponding to an
583  * AVERROR code in case of failure
584  */
585 int avio_open(AVIOContext **s, const char *url, int flags);
586 
587 /**
588  * Create and initialize a AVIOContext for accessing the
589  * resource indicated by url.
590  * @note When the resource indicated by url has been opened in
591  * read+write mode, the AVIOContext can be used only for writing.
592  *
593  * @param s Used to return the pointer to the created AVIOContext.
594  * In case of failure the pointed to value is set to NULL.
595  * @param url resource to access
596  * @param flags flags which control how the resource indicated by url
597  * is to be opened
598  * @param int_cb an interrupt callback to be used at the protocols level
599  * @param options A dictionary filled with protocol-private options. On return
600  * this parameter will be destroyed and replaced with a dict containing options
601  * that were not found. May be NULL.
602  * @return >= 0 in case of success, a negative value corresponding to an
603  * AVERROR code in case of failure
604  */
605 int avio_open2(AVIOContext **s, const char *url, int flags,
607 
608 /**
609  * Close the resource accessed by the AVIOContext s and free it.
610  * This function can only be used if s was opened by avio_open().
611  *
612  * The internal buffer is automatically flushed before closing the
613  * resource.
614  *
615  * @return 0 on success, an AVERROR < 0 on error.
616  * @see avio_closep
617  */
618 int avio_close(AVIOContext *s);
619 
620 /**
621  * Close the resource accessed by the AVIOContext *s, free it
622  * and set the pointer pointing to it to NULL.
623  * This function can only be used if s was opened by avio_open().
624  *
625  * The internal buffer is automatically flushed before closing the
626  * resource.
627  *
628  * @return 0 on success, an AVERROR < 0 on error.
629  * @see avio_close
630  */
631 int avio_closep(AVIOContext **s);
632 
633 
634 /**
635  * Open a write only memory stream.
636  *
637  * @param s new IO context
638  * @return zero if no error.
639  */
641 
642 /**
643  * Return the written size and a pointer to the buffer. The buffer
644  * must be freed with av_free().
645  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
646  *
647  * @param s IO context
648  * @param pbuffer pointer to a byte buffer
649  * @return the length of the byte buffer
650  */
651 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
652 
653 /**
654  * Iterate through names of available protocols.
655  *
656  * @param opaque A private pointer representing current protocol.
657  * It must be a pointer to NULL on first iteration and will
658  * be updated by successive calls to avio_enum_protocols.
659  * @param output If set to 1, iterate over output protocols,
660  * otherwise over input protocols.
661  *
662  * @return A static string containing the name of current protocol or NULL
663  */
664 const char *avio_enum_protocols(void **opaque, int output);
665 
666 /**
667  * Pause and resume playing - only meaningful if using a network streaming
668  * protocol (e.g. MMS).
669  *
670  * @param h IO context from which to call the read_pause function pointer
671  * @param pause 1 for pause, 0 for resume
672  */
673 int avio_pause(AVIOContext *h, int pause);
674 
675 /**
676  * Seek to a given timestamp relative to some component stream.
677  * Only meaningful if using a network streaming protocol (e.g. MMS.).
678  *
679  * @param h IO context from which to call the seek function pointers
680  * @param stream_index The stream index that the timestamp is relative to.
681  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
682  * units from the beginning of the presentation.
683  * If a stream_index >= 0 is used and the protocol does not support
684  * seeking based on component streams, the call will fail.
685  * @param timestamp timestamp in AVStream.time_base units
686  * or if there is no stream specified then in AV_TIME_BASE units.
687  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
688  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
689  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
690  * fail if used and not supported.
691  * @return >= 0 on success
692  * @see AVInputFormat::read_seek
693  */
694 int64_t avio_seek_time(AVIOContext *h, int stream_index,
695  int64_t timestamp, int flags);
696 
697 /* Avoid a warning. The header can not be included because it breaks c++. */
698 struct AVBPrint;
699 
700 /**
701  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
702  *
703  * @return 0 for success (max_size bytes read or EOF reached), negative error
704  * code otherwise
705  */
706 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
707 
708 /**
709  * Accept and allocate a client context on a server context.
710  * @param s the server context
711  * @param c the client context, must be unallocated
712  * @return >= 0 on success or a negative value corresponding
713  * to an AVERROR on failure
714  */
716 
717 /**
718  * Perform one step of the protocol handshake to accept a new client.
719  * This function must be called on a client returned by avio_accept() before
720  * using it as a read/write context.
721  * It is separate from avio_accept() because it may block.
722  * A step of the handshake is defined by places where the application may
723  * decide to change the proceedings.
724  * For example, on a protocol with a request header and a reply header, each
725  * one can constitute a step because the application may use the parameters
726  * from the request to change parameters in the reply; or each individual
727  * chunk of the request can constitute a step.
728  * If the handshake is already finished, avio_handshake() does nothing and
729  * returns 0 immediately.
730  *
731  * @param c the client context to perform the handshake on
732  * @return 0 on a complete and successful handshake
733  * > 0 if the handshake progressed, but is not complete
734  * < 0 for an AVERROR code
735  */
737 #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:979
void avio_wb64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:423
const char const char void * val
Definition: avisynth_c.h:634
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:429
const char * s
Definition: avisynth_c.h:631
Bytestream IO Context.
Definition: avio.h:111
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:292
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:202
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:1224
int64_t filemode
Unix file mode, -1 if unknown.
Definition: avio.h:92
const char * fmt
Definition: avisynth_c.h:632
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:174
int writeout_count
writeout statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:238
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:175
int write_flag
true if open for writing
Definition: avio.h:187
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:1084
Describes single entry of the directory.
Definition: avio.h:78
const char * b
Definition: vf_curves.c:109
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:213
unsigned char * buffer
Start of the buffer.
Definition: avio.h:172
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:287
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:183
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:179
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:688
int64_t maxsize
max filesize, used to limit allocations This field is internal to libavformat and access from outside...
Definition: avio.h:213
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:1212
void * opaque
Definition: avio.h:52
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:84
Public dictionary API.
int avio_accept(AVIOContext *s, AVIOContext **c)
Accept and allocate a client context on a server context.
Definition: aviobuf.c:1102
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:329
uint8_t
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:703
const AVClass * av_class
A class for private options.
Definition: avio.h:124
int64_t bytes_read
Bytes read statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:226
ptrdiff_t size
Definition: opengl_enc.c:101
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:770
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:447
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:187
const OptionDef options[]
Definition: ffserver.c:3967
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:550
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:417
int max_packet_size
Definition: avio.h:188
Callback for checking whether to abort blocking functions.
Definition: avio.h:50
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:121
char * name
Filename.
Definition: avio.h:79
int(* write_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:182
int(* callback)(void *)
Definition: avio.h:51
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:457
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:181
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:672
const char * avio_enum_protocols(void **opaque, int output)
Iterate through names of available protocols.
Definition: protocols.c:94
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
Definition: aviobuf.c:1015
int utf8
Set to 1 when name is encoded with UTF-8, 0 otherwise.
Definition: avio.h:81
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:256
unsigned long checksum
Definition: avio.h:189
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:220
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:261
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:156
int seek_count
seek statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:232
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:541
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:207
int void avio_flush(AVIOContext *s)
Force flushing of buffered data.
Definition: aviobuf.c:207
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:696
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:86
unsigned char * checksum_ptr
Definition: avio.h:190
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:447
int must_flush
true if the next seek should flush
Definition: avio.h:185
Libavformat version macros.
unsigned long(* update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size)
Definition: avio.h:191
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:83
int buffer_size
Maximum buffer size.
Definition: avio.h:173
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:345
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:80
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:165
void * buf
Definition: avisynth_c.h:553
Definition: url.h:38
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:91
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:1003
int short_seek_threshold
Threshold to favor readahead over seek.
Definition: avio.h:251
int avio_handshake(AVIOContext *c)
Perform one step of the protocol handshake to accept a new client.
Definition: aviobuf.c:1113
int avio_close_dir(AVIODirContext **s)
Close directory.
Definition: avio.c:588
int error
contains the error code or 0 if no error happened
Definition: avio.h:192
void avio_wl24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:441
int avio_pause(AVIOContext *h, int pause)
Pause and resume playing - only meaningful if using a network streaming protocol (e.g.
Definition: aviobuf.c:1058
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:196
void avio_wb16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:435
static int flags
Definition: cpu.c:47
#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:245
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:656
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:88
AVIODirEntryType
Directory entry types.
Definition: avio.h:58
static double c[64]
int64_t pos
position in the file of the current buffer
Definition: avio.h:184
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:1065
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
Definition: avio.c:575
int eof_reached
true if eof reached
Definition: avio.h:186
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:90
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:337
#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:728
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:311
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:664
struct URLContext * url_context
Definition: avio.h:96
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:1038
uint64_t avio_rl64(AVIOContext *s)
Definition: aviobuf.c:680
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:86
GLuint buffer
Definition: opengl_enc.c:102
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2