1/*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; 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
38#define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
39
40/**
41 * Callback for checking whether to abort blocking functions.
42 * AVERROR_EXIT is returned in this case by the interrupted
43 * function. During blocking operations, callback is called with
44 * opaque as parameter. If the callback returns 1, the
45 * blocking operation will be aborted.
46 *
47 * No members can be added to this struct without a major bump, if
48 * new elements have been added after this struct in AVFormatContext
49 * or AVIOContext.
50 */
51typedef struct {
52    int (*callback)(void*);
53    void *opaque;
54} AVIOInterruptCB;
55
56/**
57 * Bytestream IO Context.
58 * New fields can be added to the end with minor version bumps.
59 * Removal, reordering and changes to existing fields require a major
60 * version bump.
61 * sizeof(AVIOContext) must not be used outside libav*.
62 *
63 * @note None of the function pointers in AVIOContext should be called
64 *       directly, they should only be set by the client application
65 *       when implementing custom I/O. Normally these are set to the
66 *       function pointers specified in avio_alloc_context()
67 */
68typedef struct {
69#if !FF_API_OLD_AVIO
70    /**
71     * A class for private options.
72     *
73     * If this AVIOContext is created by avio_open2(), av_class is set and
74     * passes the options down to protocols.
75     *
76     * If this AVIOContext is manually allocated, then av_class may be set by
77     * the caller.
78     *
79     * warning -- this field can be NULL, be sure to not pass this AVIOContext
80     * to any av_opt_* functions in that case.
81     */
82    AVClass *av_class;
83#endif
84    unsigned char *buffer;  /**< Start of the buffer. */
85    int buffer_size;        /**< Maximum buffer size */
86    unsigned char *buf_ptr; /**< Current position in the buffer */
87    unsigned char *buf_end; /**< End of the data, may be less than
88                                 buffer+buffer_size if the read function returned
89                                 less data than requested, e.g. for streams where
90                                 no more data has been received yet. */
91    void *opaque;           /**< A private pointer, passed to the read/write/seek/...
92                                 functions. */
93    int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
94    int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
95    int64_t (*seek)(void *opaque, int64_t offset, int whence);
96    int64_t pos;            /**< position in the file of the current buffer */
97    int must_flush;         /**< true if the next seek should flush */
98    int eof_reached;        /**< true if eof reached */
99    int write_flag;         /**< true if open for writing */
100#if FF_API_OLD_AVIO
101    attribute_deprecated int is_streamed;
102#endif
103    int max_packet_size;
104    unsigned long checksum;
105    unsigned char *checksum_ptr;
106    unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
107    int error;              /**< contains the error code or 0 if no error happened */
108    /**
109     * Pause or resume playback for network streaming protocols - e.g. MMS.
110     */
111    int (*read_pause)(void *opaque, int pause);
112    /**
113     * Seek to a given timestamp in stream with the specified stream_index.
114     * Needed for some network streaming protocols which don't support seeking
115     * to byte position.
116     */
117    int64_t (*read_seek)(void *opaque, int stream_index,
118                         int64_t timestamp, int flags);
119    /**
120     * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
121     */
122    int seekable;
123} AVIOContext;
124
125/* unbuffered I/O */
126
127#if FF_API_OLD_AVIO
128/**
129 * URL Context.
130 * New fields can be added to the end with minor version bumps.
131 * Removal, reordering and changes to existing fields require a major
132 * version bump.
133 * sizeof(URLContext) must not be used outside libav*.
134 * @deprecated This struct will be made private
135 */
136typedef struct URLContext {
137    const AVClass *av_class; ///< information for av_log(). Set by url_open().
138    struct URLProtocol *prot;
139    int flags;
140    int is_streamed;  /**< true if streamed (no seek possible), default = false */
141    int max_packet_size;  /**< if non zero, the stream is packetized with this max packet size */
142    void *priv_data;
143    char *filename; /**< specified URL */
144    int is_connected;
145    AVIOInterruptCB interrupt_callback;
146} URLContext;
147
148#define URL_PROTOCOL_FLAG_NESTED_SCHEME 1 /*< The protocol name can be the first part of a nested protocol scheme */
149#define URL_PROTOCOL_FLAG_NETWORK       2 /*< The protocol uses network */
150
151/**
152 * @deprecated This struct is to be made private. Use the higher-level
153 *             AVIOContext-based API instead.
154 */
155typedef struct URLProtocol {
156    const char *name;
157    int (*url_open)(URLContext *h, const char *url, int flags);
158    int (*url_read)(URLContext *h, unsigned char *buf, int size);
159    int (*url_write)(URLContext *h, const unsigned char *buf, int size);
160    int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
161    int (*url_close)(URLContext *h);
162    struct URLProtocol *next;
163    int (*url_read_pause)(URLContext *h, int pause);
164    int64_t (*url_read_seek)(URLContext *h, int stream_index,
165                             int64_t timestamp, int flags);
166    int (*url_get_file_handle)(URLContext *h);
167    int priv_data_size;
168    const AVClass *priv_data_class;
169    int flags;
170    int (*url_check)(URLContext *h, int mask);
171} URLProtocol;
172
173typedef struct URLPollEntry {
174    URLContext *handle;
175    int events;
176    int revents;
177} URLPollEntry;
178
179/* not implemented */
180attribute_deprecated int url_poll(URLPollEntry *poll_table, int n, int timeout);
181
182/**
183 * @name URL open modes
184 * The flags argument to url_open and cosins must be one of the following
185 * constants, optionally ORed with other flags.
186 * @{
187 */
188#define URL_RDONLY 1  /**< read-only */
189#define URL_WRONLY 2  /**< write-only */
190#define URL_RDWR   (URL_RDONLY|URL_WRONLY)  /**< read-write */
191/**
192 * @}
193 */
194
195/**
196 * Use non-blocking mode.
197 * If this flag is set, operations on the context will return
198 * AVERROR(EAGAIN) if they can not be performed immediately.
199 * If this flag is not set, operations on the context will never return
200 * AVERROR(EAGAIN).
201 * Note that this flag does not affect the opening/connecting of the
202 * context. Connecting a protocol will always block if necessary (e.g. on
203 * network protocols) but never hang (e.g. on busy devices).
204 * Warning: non-blocking protocols is work-in-progress; this flag may be
205 * silently ignored.
206 */
207#define URL_FLAG_NONBLOCK 8
208
209typedef int URLInterruptCB(void);
210extern URLInterruptCB *url_interrupt_cb;
211
212/**
213 * @defgroup old_url_funcs Old url_* functions
214 * The following functions are deprecated. Use the buffered API based on #AVIOContext instead.
215 * @{
216 * @ingroup lavf_io
217 */
218attribute_deprecated int url_open_protocol (URLContext **puc, struct URLProtocol *up,
219                                            const char *url, int flags);
220attribute_deprecated int url_alloc(URLContext **h, const char *url, int flags);
221attribute_deprecated int url_connect(URLContext *h);
222attribute_deprecated int url_open(URLContext **h, const char *url, int flags);
223attribute_deprecated int url_read(URLContext *h, unsigned char *buf, int size);
224attribute_deprecated int url_read_complete(URLContext *h, unsigned char *buf, int size);
225attribute_deprecated int url_write(URLContext *h, const unsigned char *buf, int size);
226attribute_deprecated int64_t url_seek(URLContext *h, int64_t pos, int whence);
227attribute_deprecated int url_close(URLContext *h);
228attribute_deprecated int64_t url_filesize(URLContext *h);
229attribute_deprecated int url_get_file_handle(URLContext *h);
230attribute_deprecated int url_get_max_packet_size(URLContext *h);
231attribute_deprecated void url_get_filename(URLContext *h, char *buf, int buf_size);
232attribute_deprecated int av_url_read_pause(URLContext *h, int pause);
233attribute_deprecated int64_t av_url_read_seek(URLContext *h, int stream_index,
234                                              int64_t timestamp, int flags);
235attribute_deprecated void url_set_interrupt_cb(int (*interrupt_cb)(void));
236/**
237 * If protocol is NULL, returns the first registered protocol,
238 * if protocol is non-NULL, returns the next registered protocol after protocol,
239 * or NULL if protocol is the last one.
240 */
241attribute_deprecated URLProtocol *av_protocol_next(URLProtocol *p);
242/**
243 * Register the URLProtocol protocol.
244 *
245 * @param size the size of the URLProtocol struct referenced
246 */
247attribute_deprecated int av_register_protocol2(URLProtocol *protocol, int size);
248/**
249 * @}
250 */
251
252
253typedef attribute_deprecated AVIOContext ByteIOContext;
254
255attribute_deprecated int init_put_byte(AVIOContext *s,
256                  unsigned char *buffer,
257                  int buffer_size,
258                  int write_flag,
259                  void *opaque,
260                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
261                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
262                  int64_t (*seek)(void *opaque, int64_t offset, int whence));
263attribute_deprecated AVIOContext *av_alloc_put_byte(
264                  unsigned char *buffer,
265                  int buffer_size,
266                  int write_flag,
267                  void *opaque,
268                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
269                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
270                  int64_t (*seek)(void *opaque, int64_t offset, int whence));
271
272/**
273 * @defgroup old_avio_funcs Old put_/get_*() functions
274 * The following functions are deprecated. Use the "avio_"-prefixed functions instead.
275 * @{
276 * @ingroup lavf_io
277 */
278attribute_deprecated int          get_buffer(AVIOContext *s, unsigned char *buf, int size);
279attribute_deprecated int          get_partial_buffer(AVIOContext *s, unsigned char *buf, int size);
280attribute_deprecated int          get_byte(AVIOContext *s);
281attribute_deprecated unsigned int get_le16(AVIOContext *s);
282attribute_deprecated unsigned int get_le24(AVIOContext *s);
283attribute_deprecated unsigned int get_le32(AVIOContext *s);
284attribute_deprecated uint64_t     get_le64(AVIOContext *s);
285attribute_deprecated unsigned int get_be16(AVIOContext *s);
286attribute_deprecated unsigned int get_be24(AVIOContext *s);
287attribute_deprecated unsigned int get_be32(AVIOContext *s);
288attribute_deprecated uint64_t     get_be64(AVIOContext *s);
289
290attribute_deprecated void         put_byte(AVIOContext *s, int b);
291attribute_deprecated void         put_nbyte(AVIOContext *s, int b, int count);
292attribute_deprecated void         put_buffer(AVIOContext *s, const unsigned char *buf, int size);
293attribute_deprecated void         put_le64(AVIOContext *s, uint64_t val);
294attribute_deprecated void         put_be64(AVIOContext *s, uint64_t val);
295attribute_deprecated void         put_le32(AVIOContext *s, unsigned int val);
296attribute_deprecated void         put_be32(AVIOContext *s, unsigned int val);
297attribute_deprecated void         put_le24(AVIOContext *s, unsigned int val);
298attribute_deprecated void         put_be24(AVIOContext *s, unsigned int val);
299attribute_deprecated void         put_le16(AVIOContext *s, unsigned int val);
300attribute_deprecated void         put_be16(AVIOContext *s, unsigned int val);
301attribute_deprecated void         put_tag(AVIOContext *s, const char *tag);
302/**
303 * @}
304 */
305
306attribute_deprecated int     av_url_read_fpause(AVIOContext *h,    int pause);
307attribute_deprecated int64_t av_url_read_fseek (AVIOContext *h,    int stream_index,
308                                                int64_t timestamp, int flags);
309
310/**
311 * @defgroup old_url_f_funcs Old url_f* functions
312 * The following functions are deprecated, use the "avio_"-prefixed functions instead.
313 * @{
314 * @ingroup lavf_io
315 */
316attribute_deprecated int url_fopen( AVIOContext **s, const char *url, int flags);
317attribute_deprecated int url_fclose(AVIOContext *s);
318attribute_deprecated int64_t url_fseek(AVIOContext *s, int64_t offset, int whence);
319attribute_deprecated int url_fskip(AVIOContext *s, int64_t offset);
320attribute_deprecated int64_t url_ftell(AVIOContext *s);
321attribute_deprecated int64_t url_fsize(AVIOContext *s);
322#define URL_EOF (-1)
323attribute_deprecated int url_fgetc(AVIOContext *s);
324attribute_deprecated int url_setbufsize(AVIOContext *s, int buf_size);
325attribute_deprecated int url_fprintf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
326attribute_deprecated void put_flush_packet(AVIOContext *s);
327attribute_deprecated int url_open_dyn_buf(AVIOContext **s);
328attribute_deprecated int url_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
329attribute_deprecated int url_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
330attribute_deprecated int url_fdopen(AVIOContext **s, URLContext *h);
331/**
332 * @}
333 */
334
335/**
336 * @deprecated use AVIOContext.eof_reached
337 */
338attribute_deprecated int url_feof(AVIOContext *s);
339attribute_deprecated int url_ferror(AVIOContext *s);
340
341attribute_deprecated int udp_set_remote_url(URLContext *h, const char *uri);
342attribute_deprecated int udp_get_local_port(URLContext *h);
343
344attribute_deprecated void init_checksum(AVIOContext *s,
345                   unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
346                   unsigned long checksum);
347attribute_deprecated unsigned long get_checksum(AVIOContext *s);
348attribute_deprecated void put_strz(AVIOContext *s, const char *buf);
349/** @note unlike fgets, the EOL character is not returned and a whole
350    line is parsed. return NULL if first char read was EOF */
351attribute_deprecated char *url_fgets(AVIOContext *s, char *buf, int buf_size);
352/**
353 * @deprecated use avio_get_str instead
354 */
355attribute_deprecated char *get_strz(AVIOContext *s, char *buf, int maxlen);
356/**
357 * @deprecated Use AVIOContext.seekable field directly.
358 */
359attribute_deprecated static inline int url_is_streamed(AVIOContext *s)
360{
361    return !s->seekable;
362}
363attribute_deprecated URLContext *url_fileno(AVIOContext *s);
364
365/**
366 * @deprecated use AVIOContext.max_packet_size directly.
367 */
368attribute_deprecated int url_fget_max_packet_size(AVIOContext *s);
369
370attribute_deprecated int url_open_buf(AVIOContext **s, uint8_t *buf, int buf_size, int flags);
371
372/** return the written or read size */
373attribute_deprecated int url_close_buf(AVIOContext *s);
374
375/**
376 * Return a non-zero value if the resource indicated by url
377 * exists, 0 otherwise.
378 * @deprecated Use avio_check instead.
379 */
380attribute_deprecated int url_exist(const char *url);
381#endif // FF_API_OLD_AVIO
382
383/**
384 * Return AVIO_FLAG_* access flags corresponding to the access permissions
385 * of the resource in url, or a negative value corresponding to an
386 * AVERROR code in case of failure. The returned access flags are
387 * masked by the value in flags.
388 *
389 * @note This function is intrinsically unsafe, in the sense that the
390 * checked resource may change its existence or permission status from
391 * one call to another. Thus you should not trust the returned value,
392 * unless you are sure that no other processes are accessing the
393 * checked resource.
394 */
395int avio_check(const char *url, int flags);
396
397#if FF_API_OLD_INTERRUPT_CB
398/**
399 * The callback is called in blocking functions to test regulary if
400 * asynchronous interruption is needed. AVERROR_EXIT is returned
401 * in this case by the interrupted function. 'NULL' means no interrupt
402 * callback is given.
403 * @deprecated Use interrupt_callback in AVFormatContext/avio_open2
404 *             instead.
405 */
406attribute_deprecated void avio_set_interrupt_cb(int (*interrupt_cb)(void));
407#endif
408
409/**
410 * Allocate and initialize an AVIOContext for buffered I/O. It must be later
411 * freed with av_free().
412 *
413 * @param buffer Memory block for input/output operations via AVIOContext.
414 *        The buffer must be allocated with av_malloc() and friends.
415 * @param buffer_size The buffer size is very important for performance.
416 *        For protocols with fixed blocksize it should be set to this blocksize.
417 *        For others a typical size is a cache page, e.g. 4kb.
418 * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
419 * @param opaque An opaque pointer to user-specific data.
420 * @param read_packet  A function for refilling the buffer, may be NULL.
421 * @param write_packet A function for writing the buffer contents, may be NULL.
422 * @param seek A function for seeking to specified byte position, may be NULL.
423 *
424 * @return Allocated AVIOContext or NULL on failure.
425 */
426AVIOContext *avio_alloc_context(
427                  unsigned char *buffer,
428                  int buffer_size,
429                  int write_flag,
430                  void *opaque,
431                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
432                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
433                  int64_t (*seek)(void *opaque, int64_t offset, int whence));
434
435void avio_w8(AVIOContext *s, int b);
436void avio_write(AVIOContext *s, const unsigned char *buf, int size);
437void avio_wl64(AVIOContext *s, uint64_t val);
438void avio_wb64(AVIOContext *s, uint64_t val);
439void avio_wl32(AVIOContext *s, unsigned int val);
440void avio_wb32(AVIOContext *s, unsigned int val);
441void avio_wl24(AVIOContext *s, unsigned int val);
442void avio_wb24(AVIOContext *s, unsigned int val);
443void avio_wl16(AVIOContext *s, unsigned int val);
444void avio_wb16(AVIOContext *s, unsigned int val);
445
446/**
447 * Write a NULL-terminated string.
448 * @return number of bytes written.
449 */
450int avio_put_str(AVIOContext *s, const char *str);
451
452/**
453 * Convert an UTF-8 string to UTF-16LE and write it.
454 * @return number of bytes written.
455 */
456int avio_put_str16le(AVIOContext *s, const char *str);
457
458/**
459 * Passing this as the "whence" parameter to a seek function causes it to
460 * return the filesize without seeking anywhere. Supporting this is optional.
461 * If it is not supported then the seek function will return <0.
462 */
463#define AVSEEK_SIZE 0x10000
464
465/**
466 * Oring this flag as into the "whence" parameter to a seek function causes it to
467 * seek by any means (like reopening and linear reading) or other normally unreasonble
468 * means that can be extreemly slow.
469 * This may be ignored by the seek code.
470 */
471#define AVSEEK_FORCE 0x20000
472
473/**
474 * fseek() equivalent for AVIOContext.
475 * @return new position or AVERROR.
476 */
477int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
478
479/**
480 * Skip given number of bytes forward
481 * @return new position or AVERROR.
482 */
483static av_always_inline int64_t avio_skip(AVIOContext *s, int64_t offset)
484{
485    return avio_seek(s, offset, SEEK_CUR);
486}
487
488/**
489 * ftell() equivalent for AVIOContext.
490 * @return position or AVERROR.
491 */
492static av_always_inline int64_t avio_tell(AVIOContext *s)
493{
494    return avio_seek(s, 0, SEEK_CUR);
495}
496
497/**
498 * Get the filesize.
499 * @return filesize or AVERROR
500 */
501int64_t avio_size(AVIOContext *s);
502
503/** @warning currently size is limited */
504int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
505
506void avio_flush(AVIOContext *s);
507
508
509/**
510 * Read size bytes from AVIOContext into buf.
511 * @return number of bytes read or AVERROR
512 */
513int avio_read(AVIOContext *s, unsigned char *buf, int size);
514
515/**
516 * @name Functions for reading from AVIOContext
517 * @{
518 *
519 * @note return 0 if EOF, so you cannot use it if EOF handling is
520 *       necessary
521 */
522int          avio_r8  (AVIOContext *s);
523unsigned int avio_rl16(AVIOContext *s);
524unsigned int avio_rl24(AVIOContext *s);
525unsigned int avio_rl32(AVIOContext *s);
526uint64_t     avio_rl64(AVIOContext *s);
527unsigned int avio_rb16(AVIOContext *s);
528unsigned int avio_rb24(AVIOContext *s);
529unsigned int avio_rb32(AVIOContext *s);
530uint64_t     avio_rb64(AVIOContext *s);
531/**
532 * @}
533 */
534
535/**
536 * Read a string from pb into buf. The reading will terminate when either
537 * a NULL character was encountered, maxlen bytes have been read, or nothing
538 * more can be read from pb. The result is guaranteed to be NULL-terminated, it
539 * will be truncated if buf is too small.
540 * Note that the string is not interpreted or validated in any way, it
541 * might get truncated in the middle of a sequence for multi-byte encodings.
542 *
543 * @return number of bytes read (is always <= maxlen).
544 * If reading ends on EOF or error, the return value will be one more than
545 * bytes actually read.
546 */
547int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
548
549/**
550 * Read a UTF-16 string from pb and convert it to UTF-8.
551 * The reading will terminate when either a null or invalid character was
552 * encountered or maxlen bytes have been read.
553 * @return number of bytes read (is always <= maxlen)
554 */
555int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
556int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
557
558
559/**
560 * @name URL open modes
561 * The flags argument to avio_open must be one of the following
562 * constants, optionally ORed with other flags.
563 * @{
564 */
565#define AVIO_FLAG_READ  1                                      /**< read-only */
566#define AVIO_FLAG_WRITE 2                                      /**< write-only */
567#define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE)  /**< read-write pseudo flag */
568/**
569 * @}
570 */
571
572/**
573 * Use non-blocking mode.
574 * If this flag is set, operations on the context will return
575 * AVERROR(EAGAIN) if they can not be performed immediately.
576 * If this flag is not set, operations on the context will never return
577 * AVERROR(EAGAIN).
578 * Note that this flag does not affect the opening/connecting of the
579 * context. Connecting a protocol will always block if necessary (e.g. on
580 * network protocols) but never hang (e.g. on busy devices).
581 * Warning: non-blocking protocols is work-in-progress; this flag may be
582 * silently ignored.
583 */
584#define AVIO_FLAG_NONBLOCK 8
585
586/**
587 * Create and initialize a AVIOContext for accessing the
588 * resource indicated by url.
589 * @note When the resource indicated by url has been opened in
590 * read+write mode, the AVIOContext can be used only for writing.
591 *
592 * @param s Used to return the pointer to the created AVIOContext.
593 * In case of failure the pointed to value is set to NULL.
594 * @param flags flags which control how the resource indicated by url
595 * is to be opened
596 * @return 0 in case of success, a negative value corresponding to an
597 * AVERROR code in case of failure
598 */
599int avio_open(AVIOContext **s, const char *url, int flags);
600
601/**
602 * Create and initialize a AVIOContext for accessing the
603 * resource indicated by url.
604 * @note When the resource indicated by url has been opened in
605 * read+write mode, the AVIOContext can be used only for writing.
606 *
607 * @param s Used to return the pointer to the created AVIOContext.
608 * In case of failure the pointed to value is set to NULL.
609 * @param flags flags which control how the resource indicated by url
610 * is to be opened
611 * @param int_cb an interrupt callback to be used at the protocols level
612 * @param options  A dictionary filled with protocol-private options. On return
613 * this parameter will be destroyed and replaced with a dict containing options
614 * that were not found. May be NULL.
615 * @return 0 in case of success, a negative value corresponding to an
616 * AVERROR code in case of failure
617 */
618int avio_open2(AVIOContext **s, const char *url, int flags,
619               const AVIOInterruptCB *int_cb, AVDictionary **options);
620
621/**
622 * Close the resource accessed by the AVIOContext s and free it.
623 * This function can only be used if s was opened by avio_open().
624 *
625 * @return 0 on success, an AVERROR < 0 on error.
626 */
627int avio_close(AVIOContext *s);
628
629/**
630 * Open a write only memory stream.
631 *
632 * @param s new IO context
633 * @return zero if no error.
634 */
635int avio_open_dyn_buf(AVIOContext **s);
636
637/**
638 * Return the written size and a pointer to the buffer. The buffer
639 * must be freed with av_free().
640 * Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
641 *
642 * @param s IO context
643 * @param pbuffer pointer to a byte buffer
644 * @return the length of the byte buffer
645 */
646int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
647
648/**
649 * Iterate through names of available protocols.
650 *
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.
656 *
657 * @return A static string containing the name of current protocol or NULL
658 */
659const char *avio_enum_protocols(void **opaque, int output);
660
661/**
662 * Pause and resume playing - only meaningful if using a network streaming
663 * protocol (e.g. MMS).
664 * @param pause 1 for pause, 0 for resume
665 */
666int     avio_pause(AVIOContext *h, int pause);
667
668/**
669 * Seek to a given timestamp relative to some component stream.
670 * Only meaningful if using a network streaming protocol (e.g. MMS.).
671 * @param stream_index The stream index that the timestamp is relative to.
672 *        If stream_index is (-1) the timestamp should be in AV_TIME_BASE
673 *        units from the beginning of the presentation.
674 *        If a stream_index >= 0 is used and the protocol does not support
675 *        seeking based on component streams, the call will fail with ENOTSUP.
676 * @param timestamp timestamp in AVStream.time_base units
677 *        or if there is no stream specified then in AV_TIME_BASE units.
678 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
679 *        and AVSEEK_FLAG_ANY. The protocol may silently ignore
680 *        AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
681 *        fail with ENOTSUP if used and not supported.
682 * @return >= 0 on success
683 * @see AVInputFormat::read_seek
684 */
685int64_t avio_seek_time(AVIOContext *h, int stream_index,
686                       int64_t timestamp, int flags);
687
688#endif /* AVFORMAT_AVIO_H */
689