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,
70 * Describes single entry of the directory.
72 * Only name and type fields are guaranteed be set.
73 * Rest of fields are protocol or/and platform dependent and might be unknown.
75 typedef struct AVIODirEntry {
76 char *name; /**< Filename */
77 int type; /**< Type of the entry */
78 int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise.
79 Name can be encoded with UTF-8 eventhough 0 is set. */
80 int64_t size; /**< File size in bytes, -1 if unknown. */
81 int64_t modification_timestamp; /**< Time of last modification in microseconds since unix
82 epoch, -1 if unknown. */
83 int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch,
85 int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix
86 epoch, -1 if unknown. */
87 int64_t user_id; /**< User ID of owner, -1 if unknown. */
88 int64_t group_id; /**< Group ID of owner, -1 if unknown. */
89 int64_t filemode; /**< Unix file mode, -1 if unknown. */
92 typedef struct AVIODirContext {
93 struct URLContext *url_context;
97 * Bytestream IO Context.
98 * New fields can be added to the end with minor version bumps.
99 * Removal, reordering and changes to existing fields require a major
101 * sizeof(AVIOContext) must not be used outside libav*.
103 * @note None of the function pointers in AVIOContext should be called
104 * directly, they should only be set by the client application
105 * when implementing custom I/O. Normally these are set to the
106 * function pointers specified in avio_alloc_context()
108 typedef struct AVIOContext {
110 * A class for private options.
112 * If this AVIOContext is created by avio_open2(), av_class is set and
113 * passes the options down to protocols.
115 * If this AVIOContext is manually allocated, then av_class may be set by
118 * warning -- this field can be NULL, be sure to not pass this AVIOContext
119 * to any av_opt_* functions in that case.
121 const AVClass *av_class;
122 unsigned char *buffer; /**< Start of the buffer. */
123 int buffer_size; /**< Maximum buffer size */
124 unsigned char *buf_ptr; /**< Current position in the buffer */
125 unsigned char *buf_end; /**< End of the data, may be less than
126 buffer+buffer_size if the read function returned
127 less data than requested, e.g. for streams where
128 no more data has been received yet. */
129 void *opaque; /**< A private pointer, passed to the read/write/seek/...
131 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
132 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
133 int64_t (*seek)(void *opaque, int64_t offset, int whence);
134 int64_t pos; /**< position in the file of the current buffer */
135 int must_flush; /**< true if the next seek should flush */
136 int eof_reached; /**< true if eof reached */
137 int write_flag; /**< true if open for writing */
139 unsigned long checksum;
140 unsigned char *checksum_ptr;
141 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
142 int error; /**< contains the error code or 0 if no error happened */
144 * Pause or resume playback for network streaming protocols - e.g. MMS.
146 int (*read_pause)(void *opaque, int pause);
148 * Seek to a given timestamp in stream with the specified stream_index.
149 * Needed for some network streaming protocols which don't support seeking
152 int64_t (*read_seek)(void *opaque, int stream_index,
153 int64_t timestamp, int flags);
155 * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
160 * max filesize, used to limit allocations
161 * This field is internal to libavformat and access from outside is not allowed.
166 * avio_read and avio_write should if possible be satisfied directly
167 * instead of going through a buffer, and avio_seek will always
168 * call the underlying seek function directly.
173 * Bytes read statistic
174 * This field is internal to libavformat and access from outside is not allowed.
180 * This field is internal to libavformat and access from outside is not allowed.
186 * This field is internal to libavformat and access from outside is not allowed.
191 * Original buffer size
192 * used internally after probing and ensure seekback to reset the buffer size
193 * This field is internal to libavformat and access from outside is not allowed.
195 int orig_buffer_size;
201 * Return the name of the protocol that will handle the passed URL.
203 * NULL is returned if no protocol could be found for the given URL.
205 * @return Name of the protocol or NULL.
207 const char *avio_find_protocol_name(const char *url);
210 * Return AVIO_FLAG_* access flags corresponding to the access permissions
211 * of the resource in url, or a negative value corresponding to an
212 * AVERROR code in case of failure. The returned access flags are
213 * masked by the value in flags.
215 * @note This function is intrinsically unsafe, in the sense that the
216 * checked resource may change its existence or permission status from
217 * one call to another. Thus you should not trust the returned value,
218 * unless you are sure that no other processes are accessing the
221 int avio_check(const char *url, int flags);
224 * Open directory for reading.
226 * @param s directory read context. Pointer to a NULL pointer must be passed.
227 * @param url directory to be listed.
228 * @param options A dictionary filled with protocol-private options. On return
229 * this parameter will be destroyed and replaced with a dictionary
230 * containing options that were not found. May be NULL.
231 * @return >=0 on success or negative on error.
233 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
236 * Get next directory entry.
238 * Returned entry must be freed with avio_free_directory_entry(). In particular
239 * it may outlive AVIODirContext.
241 * @param s directory read context.
242 * @param[out] next next entry or NULL when no more entries.
243 * @return >=0 on success or negative on error. End of list is not considered an
246 int avio_read_dir(AVIODirContext *s, AVIODirEntry **next);
251 * @note Entries created using avio_read_dir() are not deleted and must be
252 * freeded with avio_free_directory_entry().
254 * @param s directory read context.
255 * @return >=0 on success or negative on error.
257 int avio_close_dir(AVIODirContext **s);
260 * Free entry allocated by avio_read_dir().
262 * @param entry entry to be freed.
264 void avio_free_directory_entry(AVIODirEntry **entry);
267 * Allocate and initialize an AVIOContext for buffered I/O. It must be later
268 * freed with av_free().
270 * @param buffer Memory block for input/output operations via AVIOContext.
271 * The buffer must be allocated with av_malloc() and friends.
272 * It may be freed and replaced with a new buffer by libavformat.
273 * AVIOContext.buffer holds the buffer currently in use,
274 * which must be later freed with av_free().
275 * @param buffer_size The buffer size is very important for performance.
276 * For protocols with fixed blocksize it should be set to this blocksize.
277 * For others a typical size is a cache page, e.g. 4kb.
278 * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
279 * @param opaque An opaque pointer to user-specific data.
280 * @param read_packet A function for refilling the buffer, may be NULL.
281 * @param write_packet A function for writing the buffer contents, may be NULL.
282 * The function may not change the input buffers content.
283 * @param seek A function for seeking to specified byte position, may be NULL.
285 * @return Allocated AVIOContext or NULL on failure.
287 AVIOContext *avio_alloc_context(
288 unsigned char *buffer,
292 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
293 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
294 int64_t (*seek)(void *opaque, int64_t offset, int whence));
296 void avio_w8(AVIOContext *s, int b);
297 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
298 void avio_wl64(AVIOContext *s, uint64_t val);
299 void avio_wb64(AVIOContext *s, uint64_t val);
300 void avio_wl32(AVIOContext *s, unsigned int val);
301 void avio_wb32(AVIOContext *s, unsigned int val);
302 void avio_wl24(AVIOContext *s, unsigned int val);
303 void avio_wb24(AVIOContext *s, unsigned int val);
304 void avio_wl16(AVIOContext *s, unsigned int val);
305 void avio_wb16(AVIOContext *s, unsigned int val);
308 * Write a NULL-terminated string.
309 * @return number of bytes written.
311 int avio_put_str(AVIOContext *s, const char *str);
314 * Convert an UTF-8 string to UTF-16LE and write it.
315 * @return number of bytes written.
317 int avio_put_str16le(AVIOContext *s, const char *str);
320 * Convert an UTF-8 string to UTF-16BE and write it.
321 * @return number of bytes written.
323 int avio_put_str16be(AVIOContext *s, const char *str);
326 * Passing this as the "whence" parameter to a seek function causes it to
327 * return the filesize without seeking anywhere. Supporting this is optional.
328 * If it is not supported then the seek function will return <0.
330 #define AVSEEK_SIZE 0x10000
333 * Oring this flag as into the "whence" parameter to a seek function causes it to
334 * seek by any means (like reopening and linear reading) or other normally unreasonable
335 * means that can be extremely slow.
336 * This may be ignored by the seek code.
338 #define AVSEEK_FORCE 0x20000
341 * fseek() equivalent for AVIOContext.
342 * @return new position or AVERROR.
344 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
347 * Skip given number of bytes forward
348 * @return new position or AVERROR.
350 int64_t avio_skip(AVIOContext *s, int64_t offset);
353 * ftell() equivalent for AVIOContext.
354 * @return position or AVERROR.
356 static av_always_inline int64_t avio_tell(AVIOContext *s)
358 return avio_seek(s, 0, SEEK_CUR);
363 * @return filesize or AVERROR
365 int64_t avio_size(AVIOContext *s);
368 * feof() equivalent for AVIOContext.
369 * @return non zero if and only if end of file
371 int avio_feof(AVIOContext *s);
374 * @deprecated use avio_feof()
377 int url_feof(AVIOContext *s);
380 /** @warning currently size is limited */
381 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
384 * Force flushing of buffered data.
386 * For write streams, force the buffered data to be immediately written to the output,
387 * without to wait to fill the internal buffer.
389 * For read streams, discard all currently buffered data, and advance the
390 * reported file position to that of the underlying stream. This does not
391 * read new data, and does not perform any seeks.
393 void avio_flush(AVIOContext *s);
396 * Read size bytes from AVIOContext into buf.
397 * @return number of bytes read or AVERROR
399 int avio_read(AVIOContext *s, unsigned char *buf, int size);
402 * @name Functions for reading from AVIOContext
405 * @note return 0 if EOF, so you cannot use it if EOF handling is
408 int avio_r8 (AVIOContext *s);
409 unsigned int avio_rl16(AVIOContext *s);
410 unsigned int avio_rl24(AVIOContext *s);
411 unsigned int avio_rl32(AVIOContext *s);
412 uint64_t avio_rl64(AVIOContext *s);
413 unsigned int avio_rb16(AVIOContext *s);
414 unsigned int avio_rb24(AVIOContext *s);
415 unsigned int avio_rb32(AVIOContext *s);
416 uint64_t avio_rb64(AVIOContext *s);
422 * Read a string from pb into buf. The reading will terminate when either
423 * a NULL character was encountered, maxlen bytes have been read, or nothing
424 * more can be read from pb. The result is guaranteed to be NULL-terminated, it
425 * will be truncated if buf is too small.
426 * Note that the string is not interpreted or validated in any way, it
427 * might get truncated in the middle of a sequence for multi-byte encodings.
429 * @return number of bytes read (is always <= maxlen).
430 * If reading ends on EOF or error, the return value will be one more than
431 * bytes actually read.
433 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
436 * Read a UTF-16 string from pb and convert it to UTF-8.
437 * The reading will terminate when either a null or invalid character was
438 * encountered or maxlen bytes have been read.
439 * @return number of bytes read (is always <= maxlen)
441 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
442 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
446 * @name URL open modes
447 * The flags argument to avio_open must be one of the following
448 * constants, optionally ORed with other flags.
451 #define AVIO_FLAG_READ 1 /**< read-only */
452 #define AVIO_FLAG_WRITE 2 /**< write-only */
453 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
459 * Use non-blocking mode.
460 * If this flag is set, operations on the context will return
461 * AVERROR(EAGAIN) if they can not be performed immediately.
462 * If this flag is not set, operations on the context will never return
464 * Note that this flag does not affect the opening/connecting of the
465 * context. Connecting a protocol will always block if necessary (e.g. on
466 * network protocols) but never hang (e.g. on busy devices).
467 * Warning: non-blocking protocols is work-in-progress; this flag may be
470 #define AVIO_FLAG_NONBLOCK 8
474 * avio_read and avio_write should if possible be satisfied directly
475 * instead of going through a buffer, and avio_seek will always
476 * call the underlying seek function directly.
478 #define AVIO_FLAG_DIRECT 0x8000
481 * Create and initialize a AVIOContext for accessing the
482 * resource indicated by url.
483 * @note When the resource indicated by url has been opened in
484 * read+write mode, the AVIOContext can be used only for writing.
486 * @param s Used to return the pointer to the created AVIOContext.
487 * In case of failure the pointed to value is set to NULL.
488 * @param url resource to access
489 * @param flags flags which control how the resource indicated by url
491 * @return >= 0 in case of success, a negative value corresponding to an
492 * AVERROR code in case of failure
494 int avio_open(AVIOContext **s, const char *url, int flags);
497 * Create and initialize a AVIOContext for accessing the
498 * resource indicated by url.
499 * @note When the resource indicated by url has been opened in
500 * read+write mode, the AVIOContext can be used only for writing.
502 * @param s Used to return the pointer to the created AVIOContext.
503 * In case of failure the pointed to value is set to NULL.
504 * @param url resource to access
505 * @param flags flags which control how the resource indicated by url
507 * @param int_cb an interrupt callback to be used at the protocols level
508 * @param options A dictionary filled with protocol-private options. On return
509 * this parameter will be destroyed and replaced with a dict containing options
510 * that were not found. May be NULL.
511 * @return >= 0 in case of success, a negative value corresponding to an
512 * AVERROR code in case of failure
514 int avio_open2(AVIOContext **s, const char *url, int flags,
515 const AVIOInterruptCB *int_cb, AVDictionary **options);
518 * Close the resource accessed by the AVIOContext s and free it.
519 * This function can only be used if s was opened by avio_open().
521 * The internal buffer is automatically flushed before closing the
524 * @return 0 on success, an AVERROR < 0 on error.
527 int avio_close(AVIOContext *s);
530 * Close the resource accessed by the AVIOContext *s, free it
531 * and set the pointer pointing to it to NULL.
532 * This function can only be used if s was opened by avio_open().
534 * The internal buffer is automatically flushed before closing the
537 * @return 0 on success, an AVERROR < 0 on error.
540 int avio_closep(AVIOContext **s);
544 * Open a write only memory stream.
546 * @param s new IO context
547 * @return zero if no error.
549 int avio_open_dyn_buf(AVIOContext **s);
552 * Return the written size and a pointer to the buffer. The buffer
553 * must be freed with av_free().
554 * Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
556 * @param s IO context
557 * @param pbuffer pointer to a byte buffer
558 * @return the length of the byte buffer
560 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
563 * Iterate through names of available protocols.
565 * @param opaque A private pointer representing current protocol.
566 * It must be a pointer to NULL on first iteration and will
567 * be updated by successive calls to avio_enum_protocols.
568 * @param output If set to 1, iterate over output protocols,
569 * otherwise over input protocols.
571 * @return A static string containing the name of current protocol or NULL
573 const char *avio_enum_protocols(void **opaque, int output);
576 * Pause and resume playing - only meaningful if using a network streaming
577 * protocol (e.g. MMS).
579 * @param h IO context from which to call the read_pause function pointer
580 * @param pause 1 for pause, 0 for resume
582 int avio_pause(AVIOContext *h, int pause);
585 * Seek to a given timestamp relative to some component stream.
586 * Only meaningful if using a network streaming protocol (e.g. MMS.).
588 * @param h IO context from which to call the seek function pointers
589 * @param stream_index The stream index that the timestamp is relative to.
590 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
591 * units from the beginning of the presentation.
592 * If a stream_index >= 0 is used and the protocol does not support
593 * seeking based on component streams, the call will fail.
594 * @param timestamp timestamp in AVStream.time_base units
595 * or if there is no stream specified then in AV_TIME_BASE units.
596 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
597 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
598 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
599 * fail if used and not supported.
600 * @return >= 0 on success
601 * @see AVInputFormat::read_seek
603 int64_t avio_seek_time(AVIOContext *h, int stream_index,
604 int64_t timestamp, int flags);
606 /* Avoid a warning. The header can not be included because it breaks c++. */
610 * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
612 * @return 0 for success (max_size bytes read or EOF reached), negative error
615 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
617 #endif /* AVFORMAT_AVIO_H */