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;
125 unsigned char *buffer; /**< Start of the buffer. */
126 int buffer_size; /**< Maximum buffer size */
127 unsigned char *buf_ptr; /**< Current position in the buffer */
128 unsigned char *buf_end; /**< End of the data, may be less than
129 buffer+buffer_size if the read function returned
130 less data than requested, e.g. for streams where
131 no more data has been received yet. */
132 void *opaque; /**< A private pointer, passed to the read/write/seek/...
134 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
135 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
136 int64_t (*seek)(void *opaque, int64_t offset, int whence);
137 int64_t pos; /**< position in the file of the current buffer */
138 int must_flush; /**< true if the next seek should flush */
139 int eof_reached; /**< true if eof reached */
140 int write_flag; /**< true if open for writing */
142 unsigned long checksum;
143 unsigned char *checksum_ptr;
144 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
145 int error; /**< contains the error code or 0 if no error happened */
147 * Pause or resume playback for network streaming protocols - e.g. MMS.
149 int (*read_pause)(void *opaque, int pause);
151 * Seek to a given timestamp in stream with the specified stream_index.
152 * Needed for some network streaming protocols which don't support seeking
155 int64_t (*read_seek)(void *opaque, int stream_index,
156 int64_t timestamp, int flags);
158 * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
163 * max filesize, used to limit allocations
164 * This field is internal to libavformat and access from outside is not allowed.
169 * avio_read and avio_write should if possible be satisfied directly
170 * instead of going through a buffer, and avio_seek will always
171 * call the underlying seek function directly.
176 * Bytes read statistic
177 * This field is internal to libavformat and access from outside is not allowed.
183 * This field is internal to libavformat and access from outside is not allowed.
189 * This field is internal to libavformat and access from outside is not allowed.
194 * Original buffer size
195 * used internally after probing and ensure seekback to reset the buffer size
196 * This field is internal to libavformat and access from outside is not allowed.
198 int orig_buffer_size;
201 * Threshold to favor readahead over seek.
202 * This is current internal only, do not use from outside.
204 int short_seek_threshold;
210 * Return the name of the protocol that will handle the passed URL.
212 * NULL is returned if no protocol could be found for the given URL.
214 * @return Name of the protocol or NULL.
216 const char *avio_find_protocol_name(const char *url);
219 * Return AVIO_FLAG_* access flags corresponding to the access permissions
220 * of the resource in url, or a negative value corresponding to an
221 * AVERROR code in case of failure. The returned access flags are
222 * masked by the value in flags.
224 * @note This function is intrinsically unsafe, in the sense that the
225 * checked resource may change its existence or permission status from
226 * one call to another. Thus you should not trust the returned value,
227 * unless you are sure that no other processes are accessing the
230 int avio_check(const char *url, int flags);
233 * Move or rename a resource.
235 * @note url_src and url_dst should share the same protocol and authority.
237 * @param url_src url to resource to be moved
238 * @param url_dst new url to resource if the operation succeeded
239 * @return >=0 on success or negative on error.
241 int avpriv_io_move(const char *url_src, const char *url_dst);
246 * @param url resource to be deleted.
247 * @return >=0 on success or negative on error.
249 int avpriv_io_delete(const char *url);
252 * Open directory for reading.
254 * @param s directory read context. Pointer to a NULL pointer must be passed.
255 * @param url directory to be listed.
256 * @param options A dictionary filled with protocol-private options. On return
257 * this parameter will be destroyed and replaced with a dictionary
258 * containing options that were not found. May be NULL.
259 * @return >=0 on success or negative on error.
261 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
264 * Get next directory entry.
266 * Returned entry must be freed with avio_free_directory_entry(). In particular
267 * it may outlive AVIODirContext.
269 * @param s directory read context.
270 * @param[out] next next entry or NULL when no more entries.
271 * @return >=0 on success or negative on error. End of list is not considered an
274 int avio_read_dir(AVIODirContext *s, AVIODirEntry **next);
279 * @note Entries created using avio_read_dir() are not deleted and must be
280 * freeded with avio_free_directory_entry().
282 * @param s directory read context.
283 * @return >=0 on success or negative on error.
285 int avio_close_dir(AVIODirContext **s);
288 * Free entry allocated by avio_read_dir().
290 * @param entry entry to be freed.
292 void avio_free_directory_entry(AVIODirEntry **entry);
295 * Allocate and initialize an AVIOContext for buffered I/O. It must be later
296 * freed with av_free().
298 * @param buffer Memory block for input/output operations via AVIOContext.
299 * The buffer must be allocated with av_malloc() and friends.
300 * It may be freed and replaced with a new buffer by libavformat.
301 * AVIOContext.buffer holds the buffer currently in use,
302 * which must be later freed with av_free().
303 * @param buffer_size The buffer size is very important for performance.
304 * For protocols with fixed blocksize it should be set to this blocksize.
305 * For others a typical size is a cache page, e.g. 4kb.
306 * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
307 * @param opaque An opaque pointer to user-specific data.
308 * @param read_packet A function for refilling the buffer, may be NULL.
309 * @param write_packet A function for writing the buffer contents, may be NULL.
310 * The function may not change the input buffers content.
311 * @param seek A function for seeking to specified byte position, may be NULL.
313 * @return Allocated AVIOContext or NULL on failure.
315 AVIOContext *avio_alloc_context(
316 unsigned char *buffer,
320 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
321 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
322 int64_t (*seek)(void *opaque, int64_t offset, int whence));
324 void avio_w8(AVIOContext *s, int b);
325 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
326 void avio_wl64(AVIOContext *s, uint64_t val);
327 void avio_wb64(AVIOContext *s, uint64_t val);
328 void avio_wl32(AVIOContext *s, unsigned int val);
329 void avio_wb32(AVIOContext *s, unsigned int val);
330 void avio_wl24(AVIOContext *s, unsigned int val);
331 void avio_wb24(AVIOContext *s, unsigned int val);
332 void avio_wl16(AVIOContext *s, unsigned int val);
333 void avio_wb16(AVIOContext *s, unsigned int val);
336 * Write a NULL-terminated string.
337 * @return number of bytes written.
339 int avio_put_str(AVIOContext *s, const char *str);
342 * Convert an UTF-8 string to UTF-16LE and write it.
343 * @param s the AVIOContext
344 * @param str NULL-terminated UTF-8 string
346 * @return number of bytes written.
348 int avio_put_str16le(AVIOContext *s, const char *str);
351 * Convert an UTF-8 string to UTF-16BE and write it.
352 * @param s the AVIOContext
353 * @param str NULL-terminated UTF-8 string
355 * @return number of bytes written.
357 int avio_put_str16be(AVIOContext *s, const char *str);
360 * Passing this as the "whence" parameter to a seek function causes it to
361 * return the filesize without seeking anywhere. Supporting this is optional.
362 * If it is not supported then the seek function will return <0.
364 #define AVSEEK_SIZE 0x10000
367 * Oring this flag as into the "whence" parameter to a seek function causes it to
368 * seek by any means (like reopening and linear reading) or other normally unreasonable
369 * means that can be extremely slow.
370 * This may be ignored by the seek code.
372 #define AVSEEK_FORCE 0x20000
375 * fseek() equivalent for AVIOContext.
376 * @return new position or AVERROR.
378 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
381 * Skip given number of bytes forward
382 * @return new position or AVERROR.
384 int64_t avio_skip(AVIOContext *s, int64_t offset);
387 * ftell() equivalent for AVIOContext.
388 * @return position or AVERROR.
390 static av_always_inline int64_t avio_tell(AVIOContext *s)
392 return avio_seek(s, 0, SEEK_CUR);
397 * @return filesize or AVERROR
399 int64_t avio_size(AVIOContext *s);
402 * feof() equivalent for AVIOContext.
403 * @return non zero if and only if end of file
405 int avio_feof(AVIOContext *s);
408 * @deprecated use avio_feof()
411 int url_feof(AVIOContext *s);
414 /** @warning currently size is limited */
415 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
418 * Force flushing of buffered data.
420 * For write streams, force the buffered data to be immediately written to the output,
421 * without to wait to fill the internal buffer.
423 * For read streams, discard all currently buffered data, and advance the
424 * reported file position to that of the underlying stream. This does not
425 * read new data, and does not perform any seeks.
427 void avio_flush(AVIOContext *s);
430 * Read size bytes from AVIOContext into buf.
431 * @return number of bytes read or AVERROR
433 int avio_read(AVIOContext *s, unsigned char *buf, int size);
436 * @name Functions for reading from AVIOContext
439 * @note return 0 if EOF, so you cannot use it if EOF handling is
442 int avio_r8 (AVIOContext *s);
443 unsigned int avio_rl16(AVIOContext *s);
444 unsigned int avio_rl24(AVIOContext *s);
445 unsigned int avio_rl32(AVIOContext *s);
446 uint64_t avio_rl64(AVIOContext *s);
447 unsigned int avio_rb16(AVIOContext *s);
448 unsigned int avio_rb24(AVIOContext *s);
449 unsigned int avio_rb32(AVIOContext *s);
450 uint64_t avio_rb64(AVIOContext *s);
456 * Read a string from pb into buf. The reading will terminate when either
457 * a NULL character was encountered, maxlen bytes have been read, or nothing
458 * more can be read from pb. The result is guaranteed to be NULL-terminated, it
459 * will be truncated if buf is too small.
460 * Note that the string is not interpreted or validated in any way, it
461 * might get truncated in the middle of a sequence for multi-byte encodings.
463 * @return number of bytes read (is always <= maxlen).
464 * If reading ends on EOF or error, the return value will be one more than
465 * bytes actually read.
467 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
470 * Read a UTF-16 string from pb and convert it to UTF-8.
471 * The reading will terminate when either a null or invalid character was
472 * encountered or maxlen bytes have been read.
473 * @return number of bytes read (is always <= maxlen)
475 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
476 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
480 * @name URL open modes
481 * The flags argument to avio_open must be one of the following
482 * constants, optionally ORed with other flags.
485 #define AVIO_FLAG_READ 1 /**< read-only */
486 #define AVIO_FLAG_WRITE 2 /**< write-only */
487 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
493 * Use non-blocking mode.
494 * If this flag is set, operations on the context will return
495 * AVERROR(EAGAIN) if they can not be performed immediately.
496 * If this flag is not set, operations on the context will never return
498 * Note that this flag does not affect the opening/connecting of the
499 * context. Connecting a protocol will always block if necessary (e.g. on
500 * network protocols) but never hang (e.g. on busy devices).
501 * Warning: non-blocking protocols is work-in-progress; this flag may be
504 #define AVIO_FLAG_NONBLOCK 8
508 * avio_read and avio_write should if possible be satisfied directly
509 * instead of going through a buffer, and avio_seek will always
510 * call the underlying seek function directly.
512 #define AVIO_FLAG_DIRECT 0x8000
515 * Create and initialize a AVIOContext for accessing the
516 * resource indicated by url.
517 * @note When the resource indicated by url has been opened in
518 * read+write mode, the AVIOContext can be used only for writing.
520 * @param s Used to return the pointer to the created AVIOContext.
521 * In case of failure the pointed to value is set to NULL.
522 * @param url resource to access
523 * @param flags flags which control how the resource indicated by url
525 * @return >= 0 in case of success, a negative value corresponding to an
526 * AVERROR code in case of failure
528 int avio_open(AVIOContext **s, const char *url, int flags);
531 * Create and initialize a AVIOContext for accessing the
532 * resource indicated by url.
533 * @note When the resource indicated by url has been opened in
534 * read+write mode, the AVIOContext can be used only for writing.
536 * @param s Used to return the pointer to the created AVIOContext.
537 * In case of failure the pointed to value is set to NULL.
538 * @param url resource to access
539 * @param flags flags which control how the resource indicated by url
541 * @param int_cb an interrupt callback to be used at the protocols level
542 * @param options A dictionary filled with protocol-private options. On return
543 * this parameter will be destroyed and replaced with a dict containing options
544 * that were not found. May be NULL.
545 * @return >= 0 in case of success, a negative value corresponding to an
546 * AVERROR code in case of failure
548 int avio_open2(AVIOContext **s, const char *url, int flags,
549 const AVIOInterruptCB *int_cb, AVDictionary **options);
552 * Close the resource accessed by the AVIOContext s and free it.
553 * This function can only be used if s was opened by avio_open().
555 * The internal buffer is automatically flushed before closing the
558 * @return 0 on success, an AVERROR < 0 on error.
561 int avio_close(AVIOContext *s);
564 * Close the resource accessed by the AVIOContext *s, free it
565 * and set the pointer pointing to it to NULL.
566 * This function can only be used if s was opened by avio_open().
568 * The internal buffer is automatically flushed before closing the
571 * @return 0 on success, an AVERROR < 0 on error.
574 int avio_closep(AVIOContext **s);
578 * Open a write only memory stream.
580 * @param s new IO context
581 * @return zero if no error.
583 int avio_open_dyn_buf(AVIOContext **s);
586 * Return the written size and a pointer to the buffer. The buffer
587 * must be freed with av_free().
588 * Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
590 * @param s IO context
591 * @param pbuffer pointer to a byte buffer
592 * @return the length of the byte buffer
594 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
597 * Iterate through names of available protocols.
599 * @param opaque A private pointer representing current protocol.
600 * It must be a pointer to NULL on first iteration and will
601 * be updated by successive calls to avio_enum_protocols.
602 * @param output If set to 1, iterate over output protocols,
603 * otherwise over input protocols.
605 * @return A static string containing the name of current protocol or NULL
607 const char *avio_enum_protocols(void **opaque, int output);
610 * Pause and resume playing - only meaningful if using a network streaming
611 * protocol (e.g. MMS).
613 * @param h IO context from which to call the read_pause function pointer
614 * @param pause 1 for pause, 0 for resume
616 int avio_pause(AVIOContext *h, int pause);
619 * Seek to a given timestamp relative to some component stream.
620 * Only meaningful if using a network streaming protocol (e.g. MMS.).
622 * @param h IO context from which to call the seek function pointers
623 * @param stream_index The stream index that the timestamp is relative to.
624 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
625 * units from the beginning of the presentation.
626 * If a stream_index >= 0 is used and the protocol does not support
627 * seeking based on component streams, the call will fail.
628 * @param timestamp timestamp in AVStream.time_base units
629 * or if there is no stream specified then in AV_TIME_BASE units.
630 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
631 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
632 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
633 * fail if used and not supported.
634 * @return >= 0 on success
635 * @see AVInputFormat::read_seek
637 int64_t avio_seek_time(AVIOContext *h, int stream_index,
638 int64_t timestamp, int flags);
640 /* Avoid a warning. The header can not be included because it breaks c++. */
644 * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
646 * @return 0 for success (max_size bytes read or EOF reached), negative error
649 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
651 #endif /* AVFORMAT_AVIO_H */