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 * Open directory for reading.
235 * @param s directory read context. Pointer to a NULL pointer must be passed.
236 * @param url directory to be listed.
237 * @param options A dictionary filled with protocol-private options. On return
238 * this parameter will be destroyed and replaced with a dictionary
239 * containing options that were not found. May be NULL.
240 * @return >=0 on success or negative on error.
242 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
245 * Get next directory entry.
247 * Returned entry must be freed with avio_free_directory_entry(). In particular
248 * it may outlive AVIODirContext.
250 * @param s directory read context.
251 * @param[out] next next entry or NULL when no more entries.
252 * @return >=0 on success or negative on error. End of list is not considered an
255 int avio_read_dir(AVIODirContext *s, AVIODirEntry **next);
260 * @note Entries created using avio_read_dir() are not deleted and must be
261 * freeded with avio_free_directory_entry().
263 * @param s directory read context.
264 * @return >=0 on success or negative on error.
266 int avio_close_dir(AVIODirContext **s);
269 * Free entry allocated by avio_read_dir().
271 * @param entry entry to be freed.
273 void avio_free_directory_entry(AVIODirEntry **entry);
276 * Allocate and initialize an AVIOContext for buffered I/O. It must be later
277 * freed with av_free().
279 * @param buffer Memory block for input/output operations via AVIOContext.
280 * The buffer must be allocated with av_malloc() and friends.
281 * It may be freed and replaced with a new buffer by libavformat.
282 * AVIOContext.buffer holds the buffer currently in use,
283 * which must be later freed with av_free().
284 * @param buffer_size The buffer size is very important for performance.
285 * For protocols with fixed blocksize it should be set to this blocksize.
286 * For others a typical size is a cache page, e.g. 4kb.
287 * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
288 * @param opaque An opaque pointer to user-specific data.
289 * @param read_packet A function for refilling the buffer, may be NULL.
290 * @param write_packet A function for writing the buffer contents, may be NULL.
291 * The function may not change the input buffers content.
292 * @param seek A function for seeking to specified byte position, may be NULL.
294 * @return Allocated AVIOContext or NULL on failure.
296 AVIOContext *avio_alloc_context(
297 unsigned char *buffer,
301 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
302 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
303 int64_t (*seek)(void *opaque, int64_t offset, int whence));
305 void avio_w8(AVIOContext *s, int b);
306 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
307 void avio_wl64(AVIOContext *s, uint64_t val);
308 void avio_wb64(AVIOContext *s, uint64_t val);
309 void avio_wl32(AVIOContext *s, unsigned int val);
310 void avio_wb32(AVIOContext *s, unsigned int val);
311 void avio_wl24(AVIOContext *s, unsigned int val);
312 void avio_wb24(AVIOContext *s, unsigned int val);
313 void avio_wl16(AVIOContext *s, unsigned int val);
314 void avio_wb16(AVIOContext *s, unsigned int val);
317 * Write a NULL-terminated string.
318 * @return number of bytes written.
320 int avio_put_str(AVIOContext *s, const char *str);
323 * Convert an UTF-8 string to UTF-16LE and write it.
324 * @param s the AVIOContext
325 * @param str NULL-terminated UTF-8 string
327 * @return number of bytes written.
329 int avio_put_str16le(AVIOContext *s, const char *str);
332 * Convert an UTF-8 string to UTF-16BE and write it.
333 * @param s the AVIOContext
334 * @param str NULL-terminated UTF-8 string
336 * @return number of bytes written.
338 int avio_put_str16be(AVIOContext *s, const char *str);
341 * Passing this as the "whence" parameter to a seek function causes it to
342 * return the filesize without seeking anywhere. Supporting this is optional.
343 * If it is not supported then the seek function will return <0.
345 #define AVSEEK_SIZE 0x10000
348 * Oring this flag as into the "whence" parameter to a seek function causes it to
349 * seek by any means (like reopening and linear reading) or other normally unreasonable
350 * means that can be extremely slow.
351 * This may be ignored by the seek code.
353 #define AVSEEK_FORCE 0x20000
356 * fseek() equivalent for AVIOContext.
357 * @return new position or AVERROR.
359 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
362 * Skip given number of bytes forward
363 * @return new position or AVERROR.
365 int64_t avio_skip(AVIOContext *s, int64_t offset);
368 * ftell() equivalent for AVIOContext.
369 * @return position or AVERROR.
371 static av_always_inline int64_t avio_tell(AVIOContext *s)
373 return avio_seek(s, 0, SEEK_CUR);
378 * @return filesize or AVERROR
380 int64_t avio_size(AVIOContext *s);
383 * feof() equivalent for AVIOContext.
384 * @return non zero if and only if end of file
386 int avio_feof(AVIOContext *s);
389 * @deprecated use avio_feof()
392 int url_feof(AVIOContext *s);
395 /** @warning currently size is limited */
396 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
399 * Force flushing of buffered data.
401 * For write streams, force the buffered data to be immediately written to the output,
402 * without to wait to fill the internal buffer.
404 * For read streams, discard all currently buffered data, and advance the
405 * reported file position to that of the underlying stream. This does not
406 * read new data, and does not perform any seeks.
408 void avio_flush(AVIOContext *s);
411 * Read size bytes from AVIOContext into buf.
412 * @return number of bytes read or AVERROR
414 int avio_read(AVIOContext *s, unsigned char *buf, int size);
417 * @name Functions for reading from AVIOContext
420 * @note return 0 if EOF, so you cannot use it if EOF handling is
423 int avio_r8 (AVIOContext *s);
424 unsigned int avio_rl16(AVIOContext *s);
425 unsigned int avio_rl24(AVIOContext *s);
426 unsigned int avio_rl32(AVIOContext *s);
427 uint64_t avio_rl64(AVIOContext *s);
428 unsigned int avio_rb16(AVIOContext *s);
429 unsigned int avio_rb24(AVIOContext *s);
430 unsigned int avio_rb32(AVIOContext *s);
431 uint64_t avio_rb64(AVIOContext *s);
437 * Read a string from pb into buf. The reading will terminate when either
438 * a NULL character was encountered, maxlen bytes have been read, or nothing
439 * more can be read from pb. The result is guaranteed to be NULL-terminated, it
440 * will be truncated if buf is too small.
441 * Note that the string is not interpreted or validated in any way, it
442 * might get truncated in the middle of a sequence for multi-byte encodings.
444 * @return number of bytes read (is always <= maxlen).
445 * If reading ends on EOF or error, the return value will be one more than
446 * bytes actually read.
448 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
451 * Read a UTF-16 string from pb and convert it to UTF-8.
452 * The reading will terminate when either a null or invalid character was
453 * encountered or maxlen bytes have been read.
454 * @return number of bytes read (is always <= maxlen)
456 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
457 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
461 * @name URL open modes
462 * The flags argument to avio_open must be one of the following
463 * constants, optionally ORed with other flags.
466 #define AVIO_FLAG_READ 1 /**< read-only */
467 #define AVIO_FLAG_WRITE 2 /**< write-only */
468 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
474 * Use non-blocking mode.
475 * If this flag is set, operations on the context will return
476 * AVERROR(EAGAIN) if they can not be performed immediately.
477 * If this flag is not set, operations on the context will never return
479 * Note that this flag does not affect the opening/connecting of the
480 * context. Connecting a protocol will always block if necessary (e.g. on
481 * network protocols) but never hang (e.g. on busy devices).
482 * Warning: non-blocking protocols is work-in-progress; this flag may be
485 #define AVIO_FLAG_NONBLOCK 8
489 * avio_read and avio_write should if possible be satisfied directly
490 * instead of going through a buffer, and avio_seek will always
491 * call the underlying seek function directly.
493 #define AVIO_FLAG_DIRECT 0x8000
496 * Create and initialize a AVIOContext for accessing the
497 * resource indicated by url.
498 * @note When the resource indicated by url has been opened in
499 * read+write mode, the AVIOContext can be used only for writing.
501 * @param s Used to return the pointer to the created AVIOContext.
502 * In case of failure the pointed to value is set to NULL.
503 * @param url resource to access
504 * @param flags flags which control how the resource indicated by url
506 * @return >= 0 in case of success, a negative value corresponding to an
507 * AVERROR code in case of failure
509 int avio_open(AVIOContext **s, const char *url, int flags);
512 * Create and initialize a AVIOContext for accessing the
513 * resource indicated by url.
514 * @note When the resource indicated by url has been opened in
515 * read+write mode, the AVIOContext can be used only for writing.
517 * @param s Used to return the pointer to the created AVIOContext.
518 * In case of failure the pointed to value is set to NULL.
519 * @param url resource to access
520 * @param flags flags which control how the resource indicated by url
522 * @param int_cb an interrupt callback to be used at the protocols level
523 * @param options A dictionary filled with protocol-private options. On return
524 * this parameter will be destroyed and replaced with a dict containing options
525 * that were not found. May be NULL.
526 * @return >= 0 in case of success, a negative value corresponding to an
527 * AVERROR code in case of failure
529 int avio_open2(AVIOContext **s, const char *url, int flags,
530 const AVIOInterruptCB *int_cb, AVDictionary **options);
533 * Close the resource accessed by the AVIOContext s and free it.
534 * This function can only be used if s was opened by avio_open().
536 * The internal buffer is automatically flushed before closing the
539 * @return 0 on success, an AVERROR < 0 on error.
542 int avio_close(AVIOContext *s);
545 * Close the resource accessed by the AVIOContext *s, free it
546 * and set the pointer pointing to it to NULL.
547 * This function can only be used if s was opened by avio_open().
549 * The internal buffer is automatically flushed before closing the
552 * @return 0 on success, an AVERROR < 0 on error.
555 int avio_closep(AVIOContext **s);
559 * Open a write only memory stream.
561 * @param s new IO context
562 * @return zero if no error.
564 int avio_open_dyn_buf(AVIOContext **s);
567 * Return the written size and a pointer to the buffer. The buffer
568 * must be freed with av_free().
569 * Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
571 * @param s IO context
572 * @param pbuffer pointer to a byte buffer
573 * @return the length of the byte buffer
575 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
578 * Iterate through names of available protocols.
580 * @param opaque A private pointer representing current protocol.
581 * It must be a pointer to NULL on first iteration and will
582 * be updated by successive calls to avio_enum_protocols.
583 * @param output If set to 1, iterate over output protocols,
584 * otherwise over input protocols.
586 * @return A static string containing the name of current protocol or NULL
588 const char *avio_enum_protocols(void **opaque, int output);
591 * Pause and resume playing - only meaningful if using a network streaming
592 * protocol (e.g. MMS).
594 * @param h IO context from which to call the read_pause function pointer
595 * @param pause 1 for pause, 0 for resume
597 int avio_pause(AVIOContext *h, int pause);
600 * Seek to a given timestamp relative to some component stream.
601 * Only meaningful if using a network streaming protocol (e.g. MMS.).
603 * @param h IO context from which to call the seek function pointers
604 * @param stream_index The stream index that the timestamp is relative to.
605 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
606 * units from the beginning of the presentation.
607 * If a stream_index >= 0 is used and the protocol does not support
608 * seeking based on component streams, the call will fail.
609 * @param timestamp timestamp in AVStream.time_base units
610 * or if there is no stream specified then in AV_TIME_BASE units.
611 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
612 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
613 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
614 * fail if used and not supported.
615 * @return >= 0 on success
616 * @see AVInputFormat::read_seek
618 int64_t avio_seek_time(AVIOContext *h, int stream_index,
619 int64_t timestamp, int flags);
621 /* Avoid a warning. The header can not be included because it breaks c++. */
625 * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
627 * @return 0 for success (max_size bytes read or EOF reached), negative error
630 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
632 #endif /* AVFORMAT_AVIO_H */