2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
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.
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.
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
20 #ifndef AVFORMAT_AVIO_H
21 #define AVFORMAT_AVIO_H
26 * Buffered I/O operations
31 #include "libavutil/common.h"
32 #include "libavutil/dict.h"
33 #include "libavutil/log.h"
35 #include "libavformat/version.h"
37 #define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
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.
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
50 typedef struct AVIOInterruptCB {
51 int (*callback)(void*);
56 * Directory entry types.
58 enum AVIODirEntryType {
60 AVIO_ENTRY_BLOCK_DEVICE,
61 AVIO_ENTRY_CHARACTER_DEVICE,
63 AVIO_ENTRY_NAMED_PIPE,
64 AVIO_ENTRY_SYMBOLIC_LINK,
73 * Describes single entry of the directory.
75 * Only name and type fields are guaranteed be set.
76 * Rest of fields are protocol or/and platform dependent and might be unknown.
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,
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. */
95 typedef struct AVIODirContext {
96 struct URLContext *url_context;
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
104 * sizeof(AVIOContext) must not be used outside libav*.
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()
111 typedef struct AVIOContext {
113 * A class for private options.
115 * If this AVIOContext is created by avio_open2(), av_class is set and
116 * passes the options down to protocols.
118 * If this AVIOContext is manually allocated, then av_class may be set by
121 * warning -- this field can be NULL, be sure to not pass this AVIOContext
122 * to any av_opt_* functions in that case.
124 const AVClass *av_class;
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):
130 **********************************************************************************
132 **********************************************************************************
135 * |---------------------------------------|
138 * buffer buf_ptr buf_end
139 * +---------------+-----------------------+
140 * |/ / / / / / / /|/ / / / / / /| |
141 * read buffer: |/ / consumed / | to be read /| |
142 * |/ / / / / / / /|/ / / / / / /| |
143 * +---------------+-----------------------+
146 * +-------------------------------------------+-----------------+
148 * +-------------------------------------------+-----------------+
151 **********************************************************************************
153 **********************************************************************************
156 * |-------------------------------|
159 * buffer buf_ptr buf_end
160 * +-------------------+-----------+
161 * |/ / / / / / / / / /| |
162 * write buffer: | / to be flushed / | |
163 * |/ / / / / / / / / /| |
164 * +-------------------+-----------+
167 * +--------------------------+-----------------------------------+
169 * +--------------------------+-----------------------------------+
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/...
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 */
194 * Pause or resume playback for network streaming protocols - e.g. MMS.
196 int (*read_pause)(void *opaque, int pause);
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
202 int64_t (*read_seek)(void *opaque, int stream_index,
203 int64_t timestamp, int flags);
205 * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
210 * max filesize, used to limit allocations
211 * This field is internal to libavformat and access from outside is not allowed.
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.
223 * Bytes read statistic
224 * This field is internal to libavformat and access from outside is not allowed.
230 * This field is internal to libavformat and access from outside is not allowed.
236 * This field is internal to libavformat and access from outside is not allowed.
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.
245 int orig_buffer_size;
248 * Threshold to favor readahead over seek.
249 * This is current internal only, do not use from outside.
251 int short_seek_threshold;
254 * ',' separated list of allowed protocols.
256 const char *protocol_whitelist;
262 * Return the name of the protocol that will handle the passed URL.
264 * NULL is returned if no protocol could be found for the given URL.
266 * @return Name of the protocol or NULL.
268 const char *avio_find_protocol_name(const char *url);
271 * Return AVIO_FLAG_* access flags corresponding to the access permissions
272 * of the resource in url, or a negative value corresponding to an
273 * AVERROR code in case of failure. The returned access flags are
274 * masked by the value in flags.
276 * @note This function is intrinsically unsafe, in the sense that the
277 * checked resource may change its existence or permission status from
278 * one call to another. Thus you should not trust the returned value,
279 * unless you are sure that no other processes are accessing the
282 int avio_check(const char *url, int flags);
285 * Move or rename a resource.
287 * @note url_src and url_dst should share the same protocol and authority.
289 * @param url_src url to resource to be moved
290 * @param url_dst new url to resource if the operation succeeded
291 * @return >=0 on success or negative on error.
293 int avpriv_io_move(const char *url_src, const char *url_dst);
298 * @param url resource to be deleted.
299 * @return >=0 on success or negative on error.
301 int avpriv_io_delete(const char *url);
304 * Open directory for reading.
306 * @param s directory read context. Pointer to a NULL pointer must be passed.
307 * @param url directory to be listed.
308 * @param options A dictionary filled with protocol-private options. On return
309 * this parameter will be destroyed and replaced with a dictionary
310 * containing options that were not found. May be NULL.
311 * @return >=0 on success or negative on error.
313 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
316 * Get next directory entry.
318 * Returned entry must be freed with avio_free_directory_entry(). In particular
319 * it may outlive AVIODirContext.
321 * @param s directory read context.
322 * @param[out] next next entry or NULL when no more entries.
323 * @return >=0 on success or negative on error. End of list is not considered an
326 int avio_read_dir(AVIODirContext *s, AVIODirEntry **next);
331 * @note Entries created using avio_read_dir() are not deleted and must be
332 * freeded with avio_free_directory_entry().
334 * @param s directory read context.
335 * @return >=0 on success or negative on error.
337 int avio_close_dir(AVIODirContext **s);
340 * Free entry allocated by avio_read_dir().
342 * @param entry entry to be freed.
344 void avio_free_directory_entry(AVIODirEntry **entry);
347 * Allocate and initialize an AVIOContext for buffered I/O. It must be later
348 * freed with av_free().
350 * @param buffer Memory block for input/output operations via AVIOContext.
351 * The buffer must be allocated with av_malloc() and friends.
352 * It may be freed and replaced with a new buffer by libavformat.
353 * AVIOContext.buffer holds the buffer currently in use,
354 * which must be later freed with av_free().
355 * @param buffer_size The buffer size is very important for performance.
356 * For protocols with fixed blocksize it should be set to this blocksize.
357 * For others a typical size is a cache page, e.g. 4kb.
358 * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
359 * @param opaque An opaque pointer to user-specific data.
360 * @param read_packet A function for refilling the buffer, may be NULL.
361 * @param write_packet A function for writing the buffer contents, may be NULL.
362 * The function may not change the input buffers content.
363 * @param seek A function for seeking to specified byte position, may be NULL.
365 * @return Allocated AVIOContext or NULL on failure.
367 AVIOContext *avio_alloc_context(
368 unsigned char *buffer,
372 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
373 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
374 int64_t (*seek)(void *opaque, int64_t offset, int whence));
376 void avio_w8(AVIOContext *s, int b);
377 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
378 void avio_wl64(AVIOContext *s, uint64_t val);
379 void avio_wb64(AVIOContext *s, uint64_t val);
380 void avio_wl32(AVIOContext *s, unsigned int val);
381 void avio_wb32(AVIOContext *s, unsigned int val);
382 void avio_wl24(AVIOContext *s, unsigned int val);
383 void avio_wb24(AVIOContext *s, unsigned int val);
384 void avio_wl16(AVIOContext *s, unsigned int val);
385 void avio_wb16(AVIOContext *s, unsigned int val);
388 * Write a NULL-terminated string.
389 * @return number of bytes written.
391 int avio_put_str(AVIOContext *s, const char *str);
394 * Convert an UTF-8 string to UTF-16LE and write it.
395 * @param s the AVIOContext
396 * @param str NULL-terminated UTF-8 string
398 * @return number of bytes written.
400 int avio_put_str16le(AVIOContext *s, const char *str);
403 * Convert an UTF-8 string to UTF-16BE and write it.
404 * @param s the AVIOContext
405 * @param str NULL-terminated UTF-8 string
407 * @return number of bytes written.
409 int avio_put_str16be(AVIOContext *s, const char *str);
412 * Passing this as the "whence" parameter to a seek function causes it to
413 * return the filesize without seeking anywhere. Supporting this is optional.
414 * If it is not supported then the seek function will return <0.
416 #define AVSEEK_SIZE 0x10000
419 * Oring this flag as into the "whence" parameter to a seek function causes it to
420 * seek by any means (like reopening and linear reading) or other normally unreasonable
421 * means that can be extremely slow.
422 * This may be ignored by the seek code.
424 #define AVSEEK_FORCE 0x20000
427 * fseek() equivalent for AVIOContext.
428 * @return new position or AVERROR.
430 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
433 * Skip given number of bytes forward
434 * @return new position or AVERROR.
436 int64_t avio_skip(AVIOContext *s, int64_t offset);
439 * ftell() equivalent for AVIOContext.
440 * @return position or AVERROR.
442 static av_always_inline int64_t avio_tell(AVIOContext *s)
444 return avio_seek(s, 0, SEEK_CUR);
449 * @return filesize or AVERROR
451 int64_t avio_size(AVIOContext *s);
454 * feof() equivalent for AVIOContext.
455 * @return non zero if and only if end of file
457 int avio_feof(AVIOContext *s);
460 * @deprecated use avio_feof()
463 int url_feof(AVIOContext *s);
466 /** @warning Writes up to 4 KiB per call */
467 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
470 * Force flushing of buffered data.
472 * For write streams, force the buffered data to be immediately written to the output,
473 * without to wait to fill the internal buffer.
475 * For read streams, discard all currently buffered data, and advance the
476 * reported file position to that of the underlying stream. This does not
477 * read new data, and does not perform any seeks.
479 void avio_flush(AVIOContext *s);
482 * Read size bytes from AVIOContext into buf.
483 * @return number of bytes read or AVERROR
485 int avio_read(AVIOContext *s, unsigned char *buf, int size);
488 * @name Functions for reading from AVIOContext
491 * @note return 0 if EOF, so you cannot use it if EOF handling is
494 int avio_r8 (AVIOContext *s);
495 unsigned int avio_rl16(AVIOContext *s);
496 unsigned int avio_rl24(AVIOContext *s);
497 unsigned int avio_rl32(AVIOContext *s);
498 uint64_t avio_rl64(AVIOContext *s);
499 unsigned int avio_rb16(AVIOContext *s);
500 unsigned int avio_rb24(AVIOContext *s);
501 unsigned int avio_rb32(AVIOContext *s);
502 uint64_t avio_rb64(AVIOContext *s);
508 * Read a string from pb into buf. The reading will terminate when either
509 * a NULL character was encountered, maxlen bytes have been read, or nothing
510 * more can be read from pb. The result is guaranteed to be NULL-terminated, it
511 * will be truncated if buf is too small.
512 * Note that the string is not interpreted or validated in any way, it
513 * might get truncated in the middle of a sequence for multi-byte encodings.
515 * @return number of bytes read (is always <= maxlen).
516 * If reading ends on EOF or error, the return value will be one more than
517 * bytes actually read.
519 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
522 * Read a UTF-16 string from pb and convert it to UTF-8.
523 * The reading will terminate when either a null or invalid character was
524 * encountered or maxlen bytes have been read.
525 * @return number of bytes read (is always <= maxlen)
527 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
528 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
532 * @name URL open modes
533 * The flags argument to avio_open must be one of the following
534 * constants, optionally ORed with other flags.
537 #define AVIO_FLAG_READ 1 /**< read-only */
538 #define AVIO_FLAG_WRITE 2 /**< write-only */
539 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
545 * Use non-blocking mode.
546 * If this flag is set, operations on the context will return
547 * AVERROR(EAGAIN) if they can not be performed immediately.
548 * If this flag is not set, operations on the context will never return
550 * Note that this flag does not affect the opening/connecting of the
551 * context. Connecting a protocol will always block if necessary (e.g. on
552 * network protocols) but never hang (e.g. on busy devices).
553 * Warning: non-blocking protocols is work-in-progress; this flag may be
556 #define AVIO_FLAG_NONBLOCK 8
560 * avio_read and avio_write should if possible be satisfied directly
561 * instead of going through a buffer, and avio_seek will always
562 * call the underlying seek function directly.
564 #define AVIO_FLAG_DIRECT 0x8000
567 * Create and initialize a AVIOContext for accessing the
568 * resource indicated by url.
569 * @note When the resource indicated by url has been opened in
570 * read+write mode, the AVIOContext can be used only for writing.
572 * @param s Used to return the pointer to the created AVIOContext.
573 * In case of failure the pointed to value is set to NULL.
574 * @param url resource to access
575 * @param flags flags which control how the resource indicated by url
577 * @return >= 0 in case of success, a negative value corresponding to an
578 * AVERROR code in case of failure
580 int avio_open(AVIOContext **s, const char *url, int flags);
583 * Create and initialize a AVIOContext for accessing the
584 * resource indicated by url.
585 * @note When the resource indicated by url has been opened in
586 * read+write mode, the AVIOContext can be used only for writing.
588 * @param s Used to return the pointer to the created AVIOContext.
589 * In case of failure the pointed to value is set to NULL.
590 * @param url resource to access
591 * @param flags flags which control how the resource indicated by url
593 * @param int_cb an interrupt callback to be used at the protocols level
594 * @param options A dictionary filled with protocol-private options. On return
595 * this parameter will be destroyed and replaced with a dict containing options
596 * that were not found. May be NULL.
597 * @return >= 0 in case of success, a negative value corresponding to an
598 * AVERROR code in case of failure
600 int avio_open2(AVIOContext **s, const char *url, int flags,
601 const AVIOInterruptCB *int_cb, AVDictionary **options);
604 * Close the resource accessed by the AVIOContext s and free it.
605 * This function can only be used if s was opened by avio_open().
607 * The internal buffer is automatically flushed before closing the
610 * @return 0 on success, an AVERROR < 0 on error.
613 int avio_close(AVIOContext *s);
616 * Close the resource accessed by the AVIOContext *s, free it
617 * and set the pointer pointing to it to NULL.
618 * This function can only be used if s was opened by avio_open().
620 * The internal buffer is automatically flushed before closing the
623 * @return 0 on success, an AVERROR < 0 on error.
626 int avio_closep(AVIOContext **s);
630 * Open a write only memory stream.
632 * @param s new IO context
633 * @return zero if no error.
635 int avio_open_dyn_buf(AVIOContext **s);
638 * Return the written size and a pointer to the buffer. The buffer
639 * must be freed with av_free().
640 * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
642 * @param s IO context
643 * @param pbuffer pointer to a byte buffer
644 * @return the length of the byte buffer
646 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
649 * Iterate through names of available protocols.
651 * @param opaque A private pointer representing current protocol.
652 * It must be a pointer to NULL on first iteration and will
653 * be updated by successive calls to avio_enum_protocols.
654 * @param output If set to 1, iterate over output protocols,
655 * otherwise over input protocols.
657 * @return A static string containing the name of current protocol or NULL
659 const char *avio_enum_protocols(void **opaque, int output);
662 * Pause and resume playing - only meaningful if using a network streaming
663 * protocol (e.g. MMS).
665 * @param h IO context from which to call the read_pause function pointer
666 * @param pause 1 for pause, 0 for resume
668 int avio_pause(AVIOContext *h, int pause);
671 * Seek to a given timestamp relative to some component stream.
672 * Only meaningful if using a network streaming protocol (e.g. MMS.).
674 * @param h IO context from which to call the seek function pointers
675 * @param stream_index The stream index that the timestamp is relative to.
676 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
677 * units from the beginning of the presentation.
678 * If a stream_index >= 0 is used and the protocol does not support
679 * seeking based on component streams, the call will fail.
680 * @param timestamp timestamp in AVStream.time_base units
681 * or if there is no stream specified then in AV_TIME_BASE units.
682 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
683 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
684 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
685 * fail if used and not supported.
686 * @return >= 0 on success
687 * @see AVInputFormat::read_seek
689 int64_t avio_seek_time(AVIOContext *h, int stream_index,
690 int64_t timestamp, int flags);
692 /* Avoid a warning. The header can not be included because it breaks c++. */
696 * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
698 * @return 0 for success (max_size bytes read or EOF reached), negative error
701 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
704 * Accept and allocate a client context on a server context.
705 * @param s the server context
706 * @param c the client context, must be unallocated
707 * @return >= 0 on success or a negative value corresponding
708 * to an AVERROR on failure
710 int avio_accept(AVIOContext *s, AVIOContext **c);
713 * Perform one step of the protocol handshake to accept a new client.
714 * This function must be called on a client returned by avio_accept() before
715 * using it as a read/write context.
716 * It is separate from avio_accept() because it may block.
717 * A step of the handshake is defined by places where the application may
718 * decide to change the proceedings.
719 * For example, on a protocol with a request header and a reply header, each
720 * one can constitute a step because the application may use the parameters
721 * from the request to change parameters in the reply; or each individual
722 * chunk of the request can constitute a step.
723 * If the handshake is already finished, avio_handshake() does nothing and
724 * returns 0 immediately.
726 * @param c the client context to perform the handshake on
727 * @return 0 on a complete and successful handshake
728 * > 0 if the handshake progressed, but is not complete
729 * < 0 for an AVERROR code
731 int avio_handshake(AVIOContext *c);
732 #endif /* AVFORMAT_AVIO_H */