LCOV - code coverage report
Current view: top level - src/libavformat - avio.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 2 2 100.0 %
Date: 2017-01-28 02:43:52 Functions: 1 1 100.0 %

          Line data    Source code
       1             : /*
       2             :  * copyright (c) 2001 Fabrice Bellard
       3             :  *
       4             :  * This file is part of FFmpeg.
       5             :  *
       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.
      10             :  *
      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.
      15             :  *
      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
      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             : #define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
      38             : 
      39             : /**
      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.
      45             :  *
      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
      48             :  * or AVIOContext.
      49             :  */
      50             : typedef struct AVIOInterruptCB {
      51             :     int (*callback)(void*);
      52             :     void *opaque;
      53             : } AVIOInterruptCB;
      54             : 
      55             : /**
      56             :  * Directory entry types.
      57             :  */
      58             : enum AVIODirEntryType {
      59             :     AVIO_ENTRY_UNKNOWN,
      60             :     AVIO_ENTRY_BLOCK_DEVICE,
      61             :     AVIO_ENTRY_CHARACTER_DEVICE,
      62             :     AVIO_ENTRY_DIRECTORY,
      63             :     AVIO_ENTRY_NAMED_PIPE,
      64             :     AVIO_ENTRY_SYMBOLIC_LINK,
      65             :     AVIO_ENTRY_SOCKET,
      66             :     AVIO_ENTRY_FILE,
      67             :     AVIO_ENTRY_SERVER,
      68             :     AVIO_ENTRY_SHARE,
      69             :     AVIO_ENTRY_WORKGROUP,
      70             : };
      71             : 
      72             : /**
      73             :  * Describes single entry of the directory.
      74             :  *
      75             :  * Only name and type fields are guaranteed be set.
      76             :  * Rest of fields are protocol or/and platform dependent and might be unknown.
      77             :  */
      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,
      87             :                                                -1 if unknown. */
      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. */
      93             : } AVIODirEntry;
      94             : 
      95             : typedef struct AVIODirContext {
      96             :     struct URLContext *url_context;
      97             : } AVIODirContext;
      98             : 
      99             : /**
     100             :  * Different data types that can be returned via the AVIO
     101             :  * write_data_type callback.
     102             :  */
     103             : enum AVIODataMarkerType {
     104             :     /**
     105             :      * Header data; this needs to be present for the stream to be decodeable.
     106             :      */
     107             :     AVIO_DATA_MARKER_HEADER,
     108             :     /**
     109             :      * A point in the output bytestream where a decoder can start decoding
     110             :      * (i.e. a keyframe). A demuxer/decoder given the data flagged with
     111             :      * AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT,
     112             :      * should give decodeable results.
     113             :      */
     114             :     AVIO_DATA_MARKER_SYNC_POINT,
     115             :     /**
     116             :      * A point in the output bytestream where a demuxer can start parsing
     117             :      * (for non self synchronizing bytestream formats). That is, any
     118             :      * non-keyframe packet start point.
     119             :      */
     120             :     AVIO_DATA_MARKER_BOUNDARY_POINT,
     121             :     /**
     122             :      * This is any, unlabelled data. It can either be a muxer not marking
     123             :      * any positions at all, it can be an actual boundary/sync point
     124             :      * that the muxer chooses not to mark, or a later part of a packet/fragment
     125             :      * that is cut into multiple write callbacks due to limited IO buffer size.
     126             :      */
     127             :     AVIO_DATA_MARKER_UNKNOWN,
     128             :     /**
     129             :      * Trailer data, which doesn't contain actual content, but only for
     130             :      * finalizing the output file.
     131             :      */
     132             :     AVIO_DATA_MARKER_TRAILER
     133             : };
     134             : 
     135             : /**
     136             :  * Bytestream IO Context.
     137             :  * New fields can be added to the end with minor version bumps.
     138             :  * Removal, reordering and changes to existing fields require a major
     139             :  * version bump.
     140             :  * sizeof(AVIOContext) must not be used outside libav*.
     141             :  *
     142             :  * @note None of the function pointers in AVIOContext should be called
     143             :  *       directly, they should only be set by the client application
     144             :  *       when implementing custom I/O. Normally these are set to the
     145             :  *       function pointers specified in avio_alloc_context()
     146             :  */
     147             : typedef struct AVIOContext {
     148             :     /**
     149             :      * A class for private options.
     150             :      *
     151             :      * If this AVIOContext is created by avio_open2(), av_class is set and
     152             :      * passes the options down to protocols.
     153             :      *
     154             :      * If this AVIOContext is manually allocated, then av_class may be set by
     155             :      * the caller.
     156             :      *
     157             :      * warning -- this field can be NULL, be sure to not pass this AVIOContext
     158             :      * to any av_opt_* functions in that case.
     159             :      */
     160             :     const AVClass *av_class;
     161             : 
     162             :     /*
     163             :      * The following shows the relationship between buffer, buf_ptr, buf_end, buf_size,
     164             :      * and pos, when reading and when writing (since AVIOContext is used for both):
     165             :      *
     166             :      **********************************************************************************
     167             :      *                                   READING
     168             :      **********************************************************************************
     169             :      *
     170             :      *                            |              buffer_size              |
     171             :      *                            |---------------------------------------|
     172             :      *                            |                                       |
     173             :      *
     174             :      *                         buffer          buf_ptr       buf_end
     175             :      *                            +---------------+-----------------------+
     176             :      *                            |/ / / / / / / /|/ / / / / / /|         |
     177             :      *  read buffer:              |/ / consumed / | to be read /|         |
     178             :      *                            |/ / / / / / / /|/ / / / / / /|         |
     179             :      *                            +---------------+-----------------------+
     180             :      *
     181             :      *                                                         pos
     182             :      *              +-------------------------------------------+-----------------+
     183             :      *  input file: |                                           |                 |
     184             :      *              +-------------------------------------------+-----------------+
     185             :      *
     186             :      *
     187             :      **********************************************************************************
     188             :      *                                   WRITING
     189             :      **********************************************************************************
     190             :      *
     191             :      *                                          |          buffer_size          |
     192             :      *                                          |-------------------------------|
     193             :      *                                          |                               |
     194             :      *
     195             :      *                                       buffer              buf_ptr     buf_end
     196             :      *                                          +-------------------+-----------+
     197             :      *                                          |/ / / / / / / / / /|           |
     198             :      *  write buffer:                           | / to be flushed / |           |
     199             :      *                                          |/ / / / / / / / / /|           |
     200             :      *                                          +-------------------+-----------+
     201             :      *
     202             :      *                                         pos
     203             :      *               +--------------------------+-----------------------------------+
     204             :      *  output file: |                          |                                   |
     205             :      *               +--------------------------+-----------------------------------+
     206             :      *
     207             :      */
     208             :     unsigned char *buffer;  /**< Start of the buffer. */
     209             :     int buffer_size;        /**< Maximum buffer size */
     210             :     unsigned char *buf_ptr; /**< Current position in the buffer */
     211             :     unsigned char *buf_end; /**< End of the data, may be less than
     212             :                                  buffer+buffer_size if the read function returned
     213             :                                  less data than requested, e.g. for streams where
     214             :                                  no more data has been received yet. */
     215             :     void *opaque;           /**< A private pointer, passed to the read/write/seek/...
     216             :                                  functions. */
     217             :     int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
     218             :     int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
     219             :     int64_t (*seek)(void *opaque, int64_t offset, int whence);
     220             :     int64_t pos;            /**< position in the file of the current buffer */
     221             :     int must_flush;         /**< true if the next seek should flush */
     222             :     int eof_reached;        /**< true if eof reached */
     223             :     int write_flag;         /**< true if open for writing */
     224             :     int max_packet_size;
     225             :     unsigned long checksum;
     226             :     unsigned char *checksum_ptr;
     227             :     unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
     228             :     int error;              /**< contains the error code or 0 if no error happened */
     229             :     /**
     230             :      * Pause or resume playback for network streaming protocols - e.g. MMS.
     231             :      */
     232             :     int (*read_pause)(void *opaque, int pause);
     233             :     /**
     234             :      * Seek to a given timestamp in stream with the specified stream_index.
     235             :      * Needed for some network streaming protocols which don't support seeking
     236             :      * to byte position.
     237             :      */
     238             :     int64_t (*read_seek)(void *opaque, int stream_index,
     239             :                          int64_t timestamp, int flags);
     240             :     /**
     241             :      * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
     242             :      */
     243             :     int seekable;
     244             : 
     245             :     /**
     246             :      * max filesize, used to limit allocations
     247             :      * This field is internal to libavformat and access from outside is not allowed.
     248             :      */
     249             :     int64_t maxsize;
     250             : 
     251             :     /**
     252             :      * avio_read and avio_write should if possible be satisfied directly
     253             :      * instead of going through a buffer, and avio_seek will always
     254             :      * call the underlying seek function directly.
     255             :      */
     256             :     int direct;
     257             : 
     258             :     /**
     259             :      * Bytes read statistic
     260             :      * This field is internal to libavformat and access from outside is not allowed.
     261             :      */
     262             :     int64_t bytes_read;
     263             : 
     264             :     /**
     265             :      * seek statistic
     266             :      * This field is internal to libavformat and access from outside is not allowed.
     267             :      */
     268             :     int seek_count;
     269             : 
     270             :     /**
     271             :      * writeout statistic
     272             :      * This field is internal to libavformat and access from outside is not allowed.
     273             :      */
     274             :     int writeout_count;
     275             : 
     276             :     /**
     277             :      * Original buffer size
     278             :      * used internally after probing and ensure seekback to reset the buffer size
     279             :      * This field is internal to libavformat and access from outside is not allowed.
     280             :      */
     281             :     int orig_buffer_size;
     282             : 
     283             :     /**
     284             :      * Threshold to favor readahead over seek.
     285             :      * This is current internal only, do not use from outside.
     286             :      */
     287             :     int short_seek_threshold;
     288             : 
     289             :     /**
     290             :      * ',' separated list of allowed protocols.
     291             :      */
     292             :     const char *protocol_whitelist;
     293             : 
     294             :     /**
     295             :      * ',' separated list of disallowed protocols.
     296             :      */
     297             :     const char *protocol_blacklist;
     298             : 
     299             :     /**
     300             :      * A callback that is used instead of write_packet.
     301             :      */
     302             :     int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size,
     303             :                            enum AVIODataMarkerType type, int64_t time);
     304             :     /**
     305             :      * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
     306             :      * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
     307             :      * small chunks of data returned from the callback).
     308             :      */
     309             :     int ignore_boundary_point;
     310             : 
     311             :     /**
     312             :      * Internal, not meant to be used from outside of AVIOContext.
     313             :      */
     314             :     enum AVIODataMarkerType current_type;
     315             :     int64_t last_time;
     316             : } AVIOContext;
     317             : 
     318             : /**
     319             :  * Return the name of the protocol that will handle the passed URL.
     320             :  *
     321             :  * NULL is returned if no protocol could be found for the given URL.
     322             :  *
     323             :  * @return Name of the protocol or NULL.
     324             :  */
     325             : const char *avio_find_protocol_name(const char *url);
     326             : 
     327             : /**
     328             :  * Return AVIO_FLAG_* access flags corresponding to the access permissions
     329             :  * of the resource in url, or a negative value corresponding to an
     330             :  * AVERROR code in case of failure. The returned access flags are
     331             :  * masked by the value in flags.
     332             :  *
     333             :  * @note This function is intrinsically unsafe, in the sense that the
     334             :  * checked resource may change its existence or permission status from
     335             :  * one call to another. Thus you should not trust the returned value,
     336             :  * unless you are sure that no other processes are accessing the
     337             :  * checked resource.
     338             :  */
     339             : int avio_check(const char *url, int flags);
     340             : 
     341             : /**
     342             :  * Move or rename a resource.
     343             :  *
     344             :  * @note url_src and url_dst should share the same protocol and authority.
     345             :  *
     346             :  * @param url_src url to resource to be moved
     347             :  * @param url_dst new url to resource if the operation succeeded
     348             :  * @return >=0 on success or negative on error.
     349             :  */
     350             : int avpriv_io_move(const char *url_src, const char *url_dst);
     351             : 
     352             : /**
     353             :  * Delete a resource.
     354             :  *
     355             :  * @param url resource to be deleted.
     356             :  * @return >=0 on success or negative on error.
     357             :  */
     358             : int avpriv_io_delete(const char *url);
     359             : 
     360             : /**
     361             :  * Open directory for reading.
     362             :  *
     363             :  * @param s       directory read context. Pointer to a NULL pointer must be passed.
     364             :  * @param url     directory to be listed.
     365             :  * @param options A dictionary filled with protocol-private options. On return
     366             :  *                this parameter will be destroyed and replaced with a dictionary
     367             :  *                containing options that were not found. May be NULL.
     368             :  * @return >=0 on success or negative on error.
     369             :  */
     370             : int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
     371             : 
     372             : /**
     373             :  * Get next directory entry.
     374             :  *
     375             :  * Returned entry must be freed with avio_free_directory_entry(). In particular
     376             :  * it may outlive AVIODirContext.
     377             :  *
     378             :  * @param s         directory read context.
     379             :  * @param[out] next next entry or NULL when no more entries.
     380             :  * @return >=0 on success or negative on error. End of list is not considered an
     381             :  *             error.
     382             :  */
     383             : int avio_read_dir(AVIODirContext *s, AVIODirEntry **next);
     384             : 
     385             : /**
     386             :  * Close directory.
     387             :  *
     388             :  * @note Entries created using avio_read_dir() are not deleted and must be
     389             :  * freeded with avio_free_directory_entry().
     390             :  *
     391             :  * @param s         directory read context.
     392             :  * @return >=0 on success or negative on error.
     393             :  */
     394             : int avio_close_dir(AVIODirContext **s);
     395             : 
     396             : /**
     397             :  * Free entry allocated by avio_read_dir().
     398             :  *
     399             :  * @param entry entry to be freed.
     400             :  */
     401             : void avio_free_directory_entry(AVIODirEntry **entry);
     402             : 
     403             : /**
     404             :  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
     405             :  * freed with av_free().
     406             :  *
     407             :  * @param buffer Memory block for input/output operations via AVIOContext.
     408             :  *        The buffer must be allocated with av_malloc() and friends.
     409             :  *        It may be freed and replaced with a new buffer by libavformat.
     410             :  *        AVIOContext.buffer holds the buffer currently in use,
     411             :  *        which must be later freed with av_free().
     412             :  * @param buffer_size The buffer size is very important for performance.
     413             :  *        For protocols with fixed blocksize it should be set to this blocksize.
     414             :  *        For others a typical size is a cache page, e.g. 4kb.
     415             :  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
     416             :  * @param opaque An opaque pointer to user-specific data.
     417             :  * @param read_packet  A function for refilling the buffer, may be NULL.
     418             :  * @param write_packet A function for writing the buffer contents, may be NULL.
     419             :  *        The function may not change the input buffers content.
     420             :  * @param seek A function for seeking to specified byte position, may be NULL.
     421             :  *
     422             :  * @return Allocated AVIOContext or NULL on failure.
     423             :  */
     424             : AVIOContext *avio_alloc_context(
     425             :                   unsigned char *buffer,
     426             :                   int buffer_size,
     427             :                   int write_flag,
     428             :                   void *opaque,
     429             :                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
     430             :                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
     431             :                   int64_t (*seek)(void *opaque, int64_t offset, int whence));
     432             : 
     433             : void avio_w8(AVIOContext *s, int b);
     434             : void avio_write(AVIOContext *s, const unsigned char *buf, int size);
     435             : void avio_wl64(AVIOContext *s, uint64_t val);
     436             : void avio_wb64(AVIOContext *s, uint64_t val);
     437             : void avio_wl32(AVIOContext *s, unsigned int val);
     438             : void avio_wb32(AVIOContext *s, unsigned int val);
     439             : void avio_wl24(AVIOContext *s, unsigned int val);
     440             : void avio_wb24(AVIOContext *s, unsigned int val);
     441             : void avio_wl16(AVIOContext *s, unsigned int val);
     442             : void avio_wb16(AVIOContext *s, unsigned int val);
     443             : 
     444             : /**
     445             :  * Write a NULL-terminated string.
     446             :  * @return number of bytes written.
     447             :  */
     448             : int avio_put_str(AVIOContext *s, const char *str);
     449             : 
     450             : /**
     451             :  * Convert an UTF-8 string to UTF-16LE and write it.
     452             :  * @param s the AVIOContext
     453             :  * @param str NULL-terminated UTF-8 string
     454             :  *
     455             :  * @return number of bytes written.
     456             :  */
     457             : int avio_put_str16le(AVIOContext *s, const char *str);
     458             : 
     459             : /**
     460             :  * Convert an UTF-8 string to UTF-16BE and write it.
     461             :  * @param s the AVIOContext
     462             :  * @param str NULL-terminated UTF-8 string
     463             :  *
     464             :  * @return number of bytes written.
     465             :  */
     466             : int avio_put_str16be(AVIOContext *s, const char *str);
     467             : 
     468             : /**
     469             :  * Mark the written bytestream as a specific type.
     470             :  *
     471             :  * Zero-length ranges are omitted from the output.
     472             :  *
     473             :  * @param time the stream time the current bytestream pos corresponds to
     474             :  *             (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
     475             :  *             applicable
     476             :  * @param type the kind of data written starting at the current pos
     477             :  */
     478             : void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
     479             : 
     480             : /**
     481             :  * ORing this as the "whence" parameter to a seek function causes it to
     482             :  * return the filesize without seeking anywhere. Supporting this is optional.
     483             :  * If it is not supported then the seek function will return <0.
     484             :  */
     485             : #define AVSEEK_SIZE 0x10000
     486             : 
     487             : /**
     488             :  * Passing this flag as the "whence" parameter to a seek function causes it to
     489             :  * seek by any means (like reopening and linear reading) or other normally unreasonable
     490             :  * means that can be extremely slow.
     491             :  * This may be ignored by the seek code.
     492             :  */
     493             : #define AVSEEK_FORCE 0x20000
     494             : 
     495             : /**
     496             :  * fseek() equivalent for AVIOContext.
     497             :  * @return new position or AVERROR.
     498             :  */
     499             : int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
     500             : 
     501             : /**
     502             :  * Skip given number of bytes forward
     503             :  * @return new position or AVERROR.
     504             :  */
     505             : int64_t avio_skip(AVIOContext *s, int64_t offset);
     506             : 
     507             : /**
     508             :  * ftell() equivalent for AVIOContext.
     509             :  * @return position or AVERROR.
     510             :  */
     511     3390172 : static av_always_inline int64_t avio_tell(AVIOContext *s)
     512             : {
     513     3390172 :     return avio_seek(s, 0, SEEK_CUR);
     514             : }
     515             : 
     516             : /**
     517             :  * Get the filesize.
     518             :  * @return filesize or AVERROR
     519             :  */
     520             : int64_t avio_size(AVIOContext *s);
     521             : 
     522             : /**
     523             :  * feof() equivalent for AVIOContext.
     524             :  * @return non zero if and only if end of file
     525             :  */
     526             : int avio_feof(AVIOContext *s);
     527             : #if FF_API_URL_FEOF
     528             : /**
     529             :  * @deprecated use avio_feof()
     530             :  */
     531             : attribute_deprecated
     532             : int url_feof(AVIOContext *s);
     533             : #endif
     534             : 
     535             : /** @warning Writes up to 4 KiB per call */
     536             : int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
     537             : 
     538             : /**
     539             :  * Force flushing of buffered data.
     540             :  *
     541             :  * For write streams, force the buffered data to be immediately written to the output,
     542             :  * without to wait to fill the internal buffer.
     543             :  *
     544             :  * For read streams, discard all currently buffered data, and advance the
     545             :  * reported file position to that of the underlying stream. This does not
     546             :  * read new data, and does not perform any seeks.
     547             :  */
     548             : void avio_flush(AVIOContext *s);
     549             : 
     550             : /**
     551             :  * Read size bytes from AVIOContext into buf.
     552             :  * @return number of bytes read or AVERROR
     553             :  */
     554             : int avio_read(AVIOContext *s, unsigned char *buf, int size);
     555             : 
     556             : /**
     557             :  * @name Functions for reading from AVIOContext
     558             :  * @{
     559             :  *
     560             :  * @note return 0 if EOF, so you cannot use it if EOF handling is
     561             :  *       necessary
     562             :  */
     563             : int          avio_r8  (AVIOContext *s);
     564             : unsigned int avio_rl16(AVIOContext *s);
     565             : unsigned int avio_rl24(AVIOContext *s);
     566             : unsigned int avio_rl32(AVIOContext *s);
     567             : uint64_t     avio_rl64(AVIOContext *s);
     568             : unsigned int avio_rb16(AVIOContext *s);
     569             : unsigned int avio_rb24(AVIOContext *s);
     570             : unsigned int avio_rb32(AVIOContext *s);
     571             : uint64_t     avio_rb64(AVIOContext *s);
     572             : /**
     573             :  * @}
     574             :  */
     575             : 
     576             : /**
     577             :  * Read a string from pb into buf. The reading will terminate when either
     578             :  * a NULL character was encountered, maxlen bytes have been read, or nothing
     579             :  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
     580             :  * will be truncated if buf is too small.
     581             :  * Note that the string is not interpreted or validated in any way, it
     582             :  * might get truncated in the middle of a sequence for multi-byte encodings.
     583             :  *
     584             :  * @return number of bytes read (is always <= maxlen).
     585             :  * If reading ends on EOF or error, the return value will be one more than
     586             :  * bytes actually read.
     587             :  */
     588             : int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
     589             : 
     590             : /**
     591             :  * Read a UTF-16 string from pb and convert it to UTF-8.
     592             :  * The reading will terminate when either a null or invalid character was
     593             :  * encountered or maxlen bytes have been read.
     594             :  * @return number of bytes read (is always <= maxlen)
     595             :  */
     596             : int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
     597             : int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
     598             : 
     599             : 
     600             : /**
     601             :  * @name URL open modes
     602             :  * The flags argument to avio_open must be one of the following
     603             :  * constants, optionally ORed with other flags.
     604             :  * @{
     605             :  */
     606             : #define AVIO_FLAG_READ  1                                      /**< read-only */
     607             : #define AVIO_FLAG_WRITE 2                                      /**< write-only */
     608             : #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE)  /**< read-write pseudo flag */
     609             : /**
     610             :  * @}
     611             :  */
     612             : 
     613             : /**
     614             :  * Use non-blocking mode.
     615             :  * If this flag is set, operations on the context will return
     616             :  * AVERROR(EAGAIN) if they can not be performed immediately.
     617             :  * If this flag is not set, operations on the context will never return
     618             :  * AVERROR(EAGAIN).
     619             :  * Note that this flag does not affect the opening/connecting of the
     620             :  * context. Connecting a protocol will always block if necessary (e.g. on
     621             :  * network protocols) but never hang (e.g. on busy devices).
     622             :  * Warning: non-blocking protocols is work-in-progress; this flag may be
     623             :  * silently ignored.
     624             :  */
     625             : #define AVIO_FLAG_NONBLOCK 8
     626             : 
     627             : /**
     628             :  * Use direct mode.
     629             :  * avio_read and avio_write should if possible be satisfied directly
     630             :  * instead of going through a buffer, and avio_seek will always
     631             :  * call the underlying seek function directly.
     632             :  */
     633             : #define AVIO_FLAG_DIRECT 0x8000
     634             : 
     635             : /**
     636             :  * Create and initialize a AVIOContext for accessing the
     637             :  * resource indicated by url.
     638             :  * @note When the resource indicated by url has been opened in
     639             :  * read+write mode, the AVIOContext can be used only for writing.
     640             :  *
     641             :  * @param s Used to return the pointer to the created AVIOContext.
     642             :  * In case of failure the pointed to value is set to NULL.
     643             :  * @param url resource to access
     644             :  * @param flags flags which control how the resource indicated by url
     645             :  * is to be opened
     646             :  * @return >= 0 in case of success, a negative value corresponding to an
     647             :  * AVERROR code in case of failure
     648             :  */
     649             : int avio_open(AVIOContext **s, const char *url, int flags);
     650             : 
     651             : /**
     652             :  * Create and initialize a AVIOContext for accessing the
     653             :  * resource indicated by url.
     654             :  * @note When the resource indicated by url has been opened in
     655             :  * read+write mode, the AVIOContext can be used only for writing.
     656             :  *
     657             :  * @param s Used to return the pointer to the created AVIOContext.
     658             :  * In case of failure the pointed to value is set to NULL.
     659             :  * @param url resource to access
     660             :  * @param flags flags which control how the resource indicated by url
     661             :  * is to be opened
     662             :  * @param int_cb an interrupt callback to be used at the protocols level
     663             :  * @param options  A dictionary filled with protocol-private options. On return
     664             :  * this parameter will be destroyed and replaced with a dict containing options
     665             :  * that were not found. May be NULL.
     666             :  * @return >= 0 in case of success, a negative value corresponding to an
     667             :  * AVERROR code in case of failure
     668             :  */
     669             : int avio_open2(AVIOContext **s, const char *url, int flags,
     670             :                const AVIOInterruptCB *int_cb, AVDictionary **options);
     671             : 
     672             : /**
     673             :  * Close the resource accessed by the AVIOContext s and free it.
     674             :  * This function can only be used if s was opened by avio_open().
     675             :  *
     676             :  * The internal buffer is automatically flushed before closing the
     677             :  * resource.
     678             :  *
     679             :  * @return 0 on success, an AVERROR < 0 on error.
     680             :  * @see avio_closep
     681             :  */
     682             : int avio_close(AVIOContext *s);
     683             : 
     684             : /**
     685             :  * Close the resource accessed by the AVIOContext *s, free it
     686             :  * and set the pointer pointing to it to NULL.
     687             :  * This function can only be used if s was opened by avio_open().
     688             :  *
     689             :  * The internal buffer is automatically flushed before closing the
     690             :  * resource.
     691             :  *
     692             :  * @return 0 on success, an AVERROR < 0 on error.
     693             :  * @see avio_close
     694             :  */
     695             : int avio_closep(AVIOContext **s);
     696             : 
     697             : 
     698             : /**
     699             :  * Open a write only memory stream.
     700             :  *
     701             :  * @param s new IO context
     702             :  * @return zero if no error.
     703             :  */
     704             : int avio_open_dyn_buf(AVIOContext **s);
     705             : 
     706             : /**
     707             :  * Return the written size and a pointer to the buffer.
     708             :  * The AVIOContext stream is left intact.
     709             :  * The buffer must NOT be freed.
     710             :  * No padding is added to the buffer.
     711             :  *
     712             :  * @param s IO context
     713             :  * @param pbuffer pointer to a byte buffer
     714             :  * @return the length of the byte buffer
     715             :  */
     716             : int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
     717             : 
     718             : /**
     719             :  * Return the written size and a pointer to the buffer. The buffer
     720             :  * must be freed with av_free().
     721             :  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
     722             :  *
     723             :  * @param s IO context
     724             :  * @param pbuffer pointer to a byte buffer
     725             :  * @return the length of the byte buffer
     726             :  */
     727             : int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
     728             : 
     729             : /**
     730             :  * Iterate through names of available protocols.
     731             :  *
     732             :  * @param opaque A private pointer representing current protocol.
     733             :  *        It must be a pointer to NULL on first iteration and will
     734             :  *        be updated by successive calls to avio_enum_protocols.
     735             :  * @param output If set to 1, iterate over output protocols,
     736             :  *               otherwise over input protocols.
     737             :  *
     738             :  * @return A static string containing the name of current protocol or NULL
     739             :  */
     740             : const char *avio_enum_protocols(void **opaque, int output);
     741             : 
     742             : /**
     743             :  * Pause and resume playing - only meaningful if using a network streaming
     744             :  * protocol (e.g. MMS).
     745             :  *
     746             :  * @param h     IO context from which to call the read_pause function pointer
     747             :  * @param pause 1 for pause, 0 for resume
     748             :  */
     749             : int     avio_pause(AVIOContext *h, int pause);
     750             : 
     751             : /**
     752             :  * Seek to a given timestamp relative to some component stream.
     753             :  * Only meaningful if using a network streaming protocol (e.g. MMS.).
     754             :  *
     755             :  * @param h IO context from which to call the seek function pointers
     756             :  * @param stream_index The stream index that the timestamp is relative to.
     757             :  *        If stream_index is (-1) the timestamp should be in AV_TIME_BASE
     758             :  *        units from the beginning of the presentation.
     759             :  *        If a stream_index >= 0 is used and the protocol does not support
     760             :  *        seeking based on component streams, the call will fail.
     761             :  * @param timestamp timestamp in AVStream.time_base units
     762             :  *        or if there is no stream specified then in AV_TIME_BASE units.
     763             :  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
     764             :  *        and AVSEEK_FLAG_ANY. The protocol may silently ignore
     765             :  *        AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
     766             :  *        fail if used and not supported.
     767             :  * @return >= 0 on success
     768             :  * @see AVInputFormat::read_seek
     769             :  */
     770             : int64_t avio_seek_time(AVIOContext *h, int stream_index,
     771             :                        int64_t timestamp, int flags);
     772             : 
     773             : /* Avoid a warning. The header can not be included because it breaks c++. */
     774             : struct AVBPrint;
     775             : 
     776             : /**
     777             :  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
     778             :  *
     779             :  * @return 0 for success (max_size bytes read or EOF reached), negative error
     780             :  * code otherwise
     781             :  */
     782             : int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
     783             : 
     784             : /**
     785             :  * Accept and allocate a client context on a server context.
     786             :  * @param  s the server context
     787             :  * @param  c the client context, must be unallocated
     788             :  * @return   >= 0 on success or a negative value corresponding
     789             :  *           to an AVERROR on failure
     790             :  */
     791             : int avio_accept(AVIOContext *s, AVIOContext **c);
     792             : 
     793             : /**
     794             :  * Perform one step of the protocol handshake to accept a new client.
     795             :  * This function must be called on a client returned by avio_accept() before
     796             :  * using it as a read/write context.
     797             :  * It is separate from avio_accept() because it may block.
     798             :  * A step of the handshake is defined by places where the application may
     799             :  * decide to change the proceedings.
     800             :  * For example, on a protocol with a request header and a reply header, each
     801             :  * one can constitute a step because the application may use the parameters
     802             :  * from the request to change parameters in the reply; or each individual
     803             :  * chunk of the request can constitute a step.
     804             :  * If the handshake is already finished, avio_handshake() does nothing and
     805             :  * returns 0 immediately.
     806             :  *
     807             :  * @param  c the client context to perform the handshake on
     808             :  * @return   0   on a complete and successful handshake
     809             :  *           > 0 if the handshake progressed, but is not complete
     810             :  *           < 0 for an AVERROR code
     811             :  */
     812             : int avio_handshake(AVIOContext *c);
     813             : #endif /* AVFORMAT_AVIO_H */

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