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Diffstat (limited to 'dependencies/include/libavformat/avio.h')
| -rw-r--r-- | dependencies/include/libavformat/avio.h | 847 |
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diff --git a/dependencies/include/libavformat/avio.h b/dependencies/include/libavformat/avio.h new file mode 100644 index 0000000..4bf6b1f --- /dev/null +++ b/dependencies/include/libavformat/avio.h @@ -0,0 +1,847 @@ +/* + * copyright (c) 2001 Fabrice Bellard + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ +#ifndef AVFORMAT_AVIO_H +#define AVFORMAT_AVIO_H + +/** + * @file + * @ingroup lavf_io + * Buffered I/O operations + */ + +#include <stdint.h> +#include <stdio.h> + +#include "libavutil/attributes.h" +#include "libavutil/dict.h" +#include "libavutil/log.h" + +#include "libavformat/version_major.h" + +/** + * Seeking works like for a local file. + */ +#define AVIO_SEEKABLE_NORMAL (1 << 0) + +/** + * Seeking by timestamp with avio_seek_time() is possible. + */ +#define AVIO_SEEKABLE_TIME (1 << 1) + +/** + * Callback for checking whether to abort blocking functions. + * AVERROR_EXIT is returned in this case by the interrupted + * function. During blocking operations, callback is called with + * opaque as parameter. If the callback returns 1, the + * blocking operation will be aborted. + * + * No members can be added to this struct without a major bump, if + * new elements have been added after this struct in AVFormatContext + * or AVIOContext. + */ +typedef struct AVIOInterruptCB { + int (*callback)(void*); + void *opaque; +} AVIOInterruptCB; + +/** + * Directory entry types. + */ +enum AVIODirEntryType { + AVIO_ENTRY_UNKNOWN, + AVIO_ENTRY_BLOCK_DEVICE, + AVIO_ENTRY_CHARACTER_DEVICE, + AVIO_ENTRY_DIRECTORY, + AVIO_ENTRY_NAMED_PIPE, + AVIO_ENTRY_SYMBOLIC_LINK, + AVIO_ENTRY_SOCKET, + AVIO_ENTRY_FILE, + AVIO_ENTRY_SERVER, + AVIO_ENTRY_SHARE, + AVIO_ENTRY_WORKGROUP, +}; + +/** + * Describes single entry of the directory. + * + * Only name and type fields are guaranteed be set. + * Rest of fields are protocol or/and platform dependent and might be unknown. + */ +typedef struct AVIODirEntry { + char *name; /**< Filename */ + int type; /**< Type of the entry */ + int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise. + Name can be encoded with UTF-8 even though 0 is set. */ + int64_t size; /**< File size in bytes, -1 if unknown. */ + int64_t modification_timestamp; /**< Time of last modification in microseconds since unix + epoch, -1 if unknown. */ + int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch, + -1 if unknown. */ + int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix + epoch, -1 if unknown. */ + int64_t user_id; /**< User ID of owner, -1 if unknown. */ + int64_t group_id; /**< Group ID of owner, -1 if unknown. */ + int64_t filemode; /**< Unix file mode, -1 if unknown. */ +} AVIODirEntry; + +#if FF_API_AVIODIRCONTEXT +typedef struct AVIODirContext { + struct URLContext *url_context; +} AVIODirContext; +#else +typedef struct AVIODirContext AVIODirContext; +#endif + +/** + * Different data types that can be returned via the AVIO + * write_data_type callback. + */ +enum AVIODataMarkerType { + /** + * Header data; this needs to be present for the stream to be decodeable. + */ + AVIO_DATA_MARKER_HEADER, + /** + * A point in the output bytestream where a decoder can start decoding + * (i.e. a keyframe). A demuxer/decoder given the data flagged with + * AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT, + * should give decodeable results. + */ + AVIO_DATA_MARKER_SYNC_POINT, + /** + * A point in the output bytestream where a demuxer can start parsing + * (for non self synchronizing bytestream formats). That is, any + * non-keyframe packet start point. + */ + AVIO_DATA_MARKER_BOUNDARY_POINT, + /** + * This is any, unlabelled data. It can either be a muxer not marking + * any positions at all, it can be an actual boundary/sync point + * that the muxer chooses not to mark, or a later part of a packet/fragment + * that is cut into multiple write callbacks due to limited IO buffer size. + */ + AVIO_DATA_MARKER_UNKNOWN, + /** + * Trailer data, which doesn't contain actual content, but only for + * finalizing the output file. + */ + AVIO_DATA_MARKER_TRAILER, + /** + * A point in the output bytestream where the underlying AVIOContext might + * flush the buffer depending on latency or buffering requirements. Typically + * means the end of a packet. + */ + AVIO_DATA_MARKER_FLUSH_POINT, +}; + +/** + * Bytestream IO Context. + * New public fields can be added with minor version bumps. + * Removal, reordering and changes to existing public fields require + * a major version bump. + * sizeof(AVIOContext) must not be used outside libav*. + * + * @note None of the function pointers in AVIOContext should be called + * directly, they should only be set by the client application + * when implementing custom I/O. Normally these are set to the + * function pointers specified in avio_alloc_context() + */ +typedef struct AVIOContext { + /** + * A class for private options. + * + * If this AVIOContext is created by avio_open2(), av_class is set and + * passes the options down to protocols. + * + * If this AVIOContext is manually allocated, then av_class may be set by + * the caller. + * + * warning -- this field can be NULL, be sure to not pass this AVIOContext + * to any av_opt_* functions in that case. + */ + const AVClass *av_class; + + /* + * The following shows the relationship between buffer, buf_ptr, + * buf_ptr_max, buf_end, buf_size, and pos, when reading and when writing + * (since AVIOContext is used for both): + * + ********************************************************************************** + * READING + ********************************************************************************** + * + * | buffer_size | + * |---------------------------------------| + * | | + * + * buffer buf_ptr buf_end + * +---------------+-----------------------+ + * |/ / / / / / / /|/ / / / / / /| | + * read buffer: |/ / consumed / | to be read /| | + * |/ / / / / / / /|/ / / / / / /| | + * +---------------+-----------------------+ + * + * pos + * +-------------------------------------------+-----------------+ + * input file: | | | + * +-------------------------------------------+-----------------+ + * + * + ********************************************************************************** + * WRITING + ********************************************************************************** + * + * | buffer_size | + * |--------------------------------------| + * | | + * + * buf_ptr_max + * buffer (buf_ptr) buf_end + * +-----------------------+--------------+ + * |/ / / / / / / / / / / /| | + * write buffer: | / / to be flushed / / | | + * |/ / / / / / / / / / / /| | + * +-----------------------+--------------+ + * buf_ptr can be in this + * due to a backward seek + * + * pos + * +-------------+----------------------------------------------+ + * output file: | | | + * +-------------+----------------------------------------------+ + * + */ + unsigned char *buffer; /**< Start of the buffer. */ + int buffer_size; /**< Maximum buffer size */ + unsigned char *buf_ptr; /**< Current position in the buffer */ + unsigned char *buf_end; /**< End of the data, may be less than + buffer+buffer_size if the read function returned + less data than requested, e.g. for streams where + no more data has been received yet. */ + void *opaque; /**< A private pointer, passed to the read/write/seek/... + functions. */ + int (*read_packet)(void *opaque, uint8_t *buf, int buf_size); + int (*write_packet)(void *opaque, uint8_t *buf, int buf_size); + int64_t (*seek)(void *opaque, int64_t offset, int whence); + int64_t pos; /**< position in the file of the current buffer */ + int eof_reached; /**< true if was unable to read due to error or eof */ + int error; /**< contains the error code or 0 if no error happened */ + int write_flag; /**< true if open for writing */ + int max_packet_size; + int min_packet_size; /**< Try to buffer at least this amount of data + before flushing it. */ + unsigned long checksum; + unsigned char *checksum_ptr; + unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size); + /** + * Pause or resume playback for network streaming protocols - e.g. MMS. + */ + int (*read_pause)(void *opaque, int pause); + /** + * Seek to a given timestamp in stream with the specified stream_index. + * Needed for some network streaming protocols which don't support seeking + * to byte position. + */ + int64_t (*read_seek)(void *opaque, int stream_index, + int64_t timestamp, int flags); + /** + * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable. + */ + int seekable; + + /** + * avio_read and avio_write should if possible be satisfied directly + * instead of going through a buffer, and avio_seek will always + * call the underlying seek function directly. + */ + int direct; + + /** + * ',' separated list of allowed protocols. + */ + const char *protocol_whitelist; + + /** + * ',' separated list of disallowed protocols. + */ + const char *protocol_blacklist; + + /** + * A callback that is used instead of write_packet. + */ + int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size, + enum AVIODataMarkerType type, int64_t time); + /** + * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT, + * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly + * small chunks of data returned from the callback). + */ + int ignore_boundary_point; + +#if FF_API_AVIOCONTEXT_WRITTEN + /** + * @deprecated field utilized privately by libavformat. For a public + * statistic of how many bytes were written out, see + * AVIOContext::bytes_written. + */ + attribute_deprecated + int64_t written; +#endif + + /** + * Maximum reached position before a backward seek in the write buffer, + * used keeping track of already written data for a later flush. + */ + unsigned char *buf_ptr_max; + + /** + * Read-only statistic of bytes read for this AVIOContext. + */ + int64_t bytes_read; + + /** + * Read-only statistic of bytes written for this AVIOContext. + */ + int64_t bytes_written; +} AVIOContext; + +/** + * Return the name of the protocol that will handle the passed URL. + * + * NULL is returned if no protocol could be found for the given URL. + * + * @return Name of the protocol or NULL. + */ +const char *avio_find_protocol_name(const char *url); + +/** + * Return AVIO_FLAG_* access flags corresponding to the access permissions + * of the resource in url, or a negative value corresponding to an + * AVERROR code in case of failure. The returned access flags are + * masked by the value in flags. + * + * @note This function is intrinsically unsafe, in the sense that the + * checked resource may change its existence or permission status from + * one call to another. Thus you should not trust the returned value, + * unless you are sure that no other processes are accessing the + * checked resource. + */ +int avio_check(const char *url, int flags); + +/** + * Open directory for reading. + * + * @param s directory read context. Pointer to a NULL pointer must be passed. + * @param url directory to be listed. + * @param options A dictionary filled with protocol-private options. On return + * this parameter will be destroyed and replaced with a dictionary + * containing options that were not found. May be NULL. + * @return >=0 on success or negative on error. + */ +int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options); + +/** + * Get next directory entry. + * + * Returned entry must be freed with avio_free_directory_entry(). In particular + * it may outlive AVIODirContext. + * + * @param s directory read context. + * @param[out] next next entry or NULL when no more entries. + * @return >=0 on success or negative on error. End of list is not considered an + * error. + */ +int avio_read_dir(AVIODirContext *s, AVIODirEntry **next); + +/** + * Close directory. + * + * @note Entries created using avio_read_dir() are not deleted and must be + * freeded with avio_free_directory_entry(). + * + * @param s directory read context. + * @return >=0 on success or negative on error. + */ +int avio_close_dir(AVIODirContext **s); + +/** + * Free entry allocated by avio_read_dir(). + * + * @param entry entry to be freed. + */ +void avio_free_directory_entry(AVIODirEntry **entry); + +/** + * Allocate and initialize an AVIOContext for buffered I/O. It must be later + * freed with avio_context_free(). + * + * @param buffer Memory block for input/output operations via AVIOContext. + * The buffer must be allocated with av_malloc() and friends. + * It may be freed and replaced with a new buffer by libavformat. + * AVIOContext.buffer holds the buffer currently in use, + * which must be later freed with av_free(). + * @param buffer_size The buffer size is very important for performance. + * For protocols with fixed blocksize it should be set to this blocksize. + * For others a typical size is a cache page, e.g. 4kb. + * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise. + * @param opaque An opaque pointer to user-specific data. + * @param read_packet A function for refilling the buffer, may be NULL. + * For stream protocols, must never return 0 but rather + * a proper AVERROR code. + * @param write_packet A function for writing the buffer contents, may be NULL. + * The function may not change the input buffers content. + * @param seek A function for seeking to specified byte position, may be NULL. + * + * @return Allocated AVIOContext or NULL on failure. + */ +AVIOContext *avio_alloc_context( + unsigned char *buffer, + int buffer_size, + int write_flag, + void *opaque, + int (*read_packet)(void *opaque, uint8_t *buf, int buf_size), + int (*write_packet)(void *opaque, uint8_t *buf, int buf_size), + int64_t (*seek)(void *opaque, int64_t offset, int whence)); + +/** + * Free the supplied IO context and everything associated with it. + * + * @param s Double pointer to the IO context. This function will write NULL + * into s. + */ +void avio_context_free(AVIOContext **s); + +void avio_w8(AVIOContext *s, int b); +void avio_write(AVIOContext *s, const unsigned char *buf, int size); +void avio_wl64(AVIOContext *s, uint64_t val); +void avio_wb64(AVIOContext *s, uint64_t val); +void avio_wl32(AVIOContext *s, unsigned int val); +void avio_wb32(AVIOContext *s, unsigned int val); +void avio_wl24(AVIOContext *s, unsigned int val); +void avio_wb24(AVIOContext *s, unsigned int val); +void avio_wl16(AVIOContext *s, unsigned int val); +void avio_wb16(AVIOContext *s, unsigned int val); + +/** + * Write a NULL-terminated string. + * @return number of bytes written. + */ +int avio_put_str(AVIOContext *s, const char *str); + +/** + * Convert an UTF-8 string to UTF-16LE and write it. + * @param s the AVIOContext + * @param str NULL-terminated UTF-8 string + * + * @return number of bytes written. + */ +int avio_put_str16le(AVIOContext *s, const char *str); + +/** + * Convert an UTF-8 string to UTF-16BE and write it. + * @param s the AVIOContext + * @param str NULL-terminated UTF-8 string + * + * @return number of bytes written. + */ +int avio_put_str16be(AVIOContext *s, const char *str); + +/** + * Mark the written bytestream as a specific type. + * + * Zero-length ranges are omitted from the output. + * + * @param s the AVIOContext + * @param time the stream time the current bytestream pos corresponds to + * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not + * applicable + * @param type the kind of data written starting at the current pos + */ +void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type); + +/** + * ORing this as the "whence" parameter to a seek function causes it to + * return the filesize without seeking anywhere. Supporting this is optional. + * If it is not supported then the seek function will return <0. + */ +#define AVSEEK_SIZE 0x10000 + +/** + * Passing this flag as the "whence" parameter to a seek function causes it to + * seek by any means (like reopening and linear reading) or other normally unreasonable + * means that can be extremely slow. + * This may be ignored by the seek code. + */ +#define AVSEEK_FORCE 0x20000 + +/** + * fseek() equivalent for AVIOContext. + * @return new position or AVERROR. + */ +int64_t avio_seek(AVIOContext *s, int64_t offset, int whence); + +/** + * Skip given number of bytes forward + * @return new position or AVERROR. + */ +int64_t avio_skip(AVIOContext *s, int64_t offset); + +/** + * ftell() equivalent for AVIOContext. + * @return position or AVERROR. + */ +static av_always_inline int64_t avio_tell(AVIOContext *s) +{ + return avio_seek(s, 0, SEEK_CUR); +} + +/** + * Get the filesize. + * @return filesize or AVERROR + */ +int64_t avio_size(AVIOContext *s); + +/** + * Similar to feof() but also returns nonzero on read errors. + * @return non zero if and only if at end of file or a read error happened when reading. + */ +int avio_feof(AVIOContext *s); + +/** + * Writes a formatted string to the context taking a va_list. + * @return number of bytes written, < 0 on error. + */ +int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap); + +/** + * Writes a formatted string to the context. + * @return number of bytes written, < 0 on error. + */ +int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3); + +/** + * Write a NULL terminated array of strings to the context. + * Usually you don't need to use this function directly but its macro wrapper, + * avio_print. + */ +void avio_print_string_array(AVIOContext *s, const char *strings[]); + +/** + * Write strings (const char *) to the context. + * This is a convenience macro around avio_print_string_array and it + * automatically creates the string array from the variable argument list. + * For simple string concatenations this function is more performant than using + * avio_printf since it does not need a temporary buffer. + */ +#define avio_print(s, ...) \ + avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL}) + +/** + * Force flushing of buffered data. + * + * For write streams, force the buffered data to be immediately written to the output, + * without to wait to fill the internal buffer. + * + * For read streams, discard all currently buffered data, and advance the + * reported file position to that of the underlying stream. This does not + * read new data, and does not perform any seeks. + */ +void avio_flush(AVIOContext *s); + +/** + * Read size bytes from AVIOContext into buf. + * @return number of bytes read or AVERROR + */ +int avio_read(AVIOContext *s, unsigned char *buf, int size); + +/** + * Read size bytes from AVIOContext into buf. Unlike avio_read(), this is allowed + * to read fewer bytes than requested. The missing bytes can be read in the next + * call. This always tries to read at least 1 byte. + * Useful to reduce latency in certain cases. + * @return number of bytes read or AVERROR + */ +int avio_read_partial(AVIOContext *s, unsigned char *buf, int size); + +/** + * @name Functions for reading from AVIOContext + * @{ + * + * @note return 0 if EOF, so you cannot use it if EOF handling is + * necessary + */ +int avio_r8 (AVIOContext *s); +unsigned int avio_rl16(AVIOContext *s); +unsigned int avio_rl24(AVIOContext *s); +unsigned int avio_rl32(AVIOContext *s); +uint64_t avio_rl64(AVIOContext *s); +unsigned int avio_rb16(AVIOContext *s); +unsigned int avio_rb24(AVIOContext *s); +unsigned int avio_rb32(AVIOContext *s); +uint64_t avio_rb64(AVIOContext *s); +/** + * @} + */ + +/** + * Read a string from pb into buf. The reading will terminate when either + * a NULL character was encountered, maxlen bytes have been read, or nothing + * more can be read from pb. The result is guaranteed to be NULL-terminated, it + * will be truncated if buf is too small. + * Note that the string is not interpreted or validated in any way, it + * might get truncated in the middle of a sequence for multi-byte encodings. + * + * @return number of bytes read (is always <= maxlen). + * If reading ends on EOF or error, the return value will be one more than + * bytes actually read. + */ +int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen); + +/** + * Read a UTF-16 string from pb and convert it to UTF-8. + * The reading will terminate when either a null or invalid character was + * encountered or maxlen bytes have been read. + * @return number of bytes read (is always <= maxlen) + */ +int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen); +int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen); + + +/** + * @name URL open modes + * The flags argument to avio_open must be one of the following + * constants, optionally ORed with other flags. + * @{ + */ +#define AVIO_FLAG_READ 1 /**< read-only */ +#define AVIO_FLAG_WRITE 2 /**< write-only */ +#define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */ +/** + * @} + */ + +/** + * Use non-blocking mode. + * If this flag is set, operations on the context will return + * AVERROR(EAGAIN) if they can not be performed immediately. + * If this flag is not set, operations on the context will never return + * AVERROR(EAGAIN). + * Note that this flag does not affect the opening/connecting of the + * context. Connecting a protocol will always block if necessary (e.g. on + * network protocols) but never hang (e.g. on busy devices). + * Warning: non-blocking protocols is work-in-progress; this flag may be + * silently ignored. + */ +#define AVIO_FLAG_NONBLOCK 8 + +/** + * Use direct mode. + * avio_read and avio_write should if possible be satisfied directly + * instead of going through a buffer, and avio_seek will always + * call the underlying seek function directly. + */ +#define AVIO_FLAG_DIRECT 0x8000 + +/** + * Create and initialize a AVIOContext for accessing the + * resource indicated by url. + * @note When the resource indicated by url has been opened in + * read+write mode, the AVIOContext can be used only for writing. + * + * @param s Used to return the pointer to the created AVIOContext. + * In case of failure the pointed to value is set to NULL. + * @param url resource to access + * @param flags flags which control how the resource indicated by url + * is to be opened + * @return >= 0 in case of success, a negative value corresponding to an + * AVERROR code in case of failure + */ +int avio_open(AVIOContext **s, const char *url, int flags); + +/** + * Create and initialize a AVIOContext for accessing the + * resource indicated by url. + * @note When the resource indicated by url has been opened in + * read+write mode, the AVIOContext can be used only for writing. + * + * @param s Used to return the pointer to the created AVIOContext. + * In case of failure the pointed to value is set to NULL. + * @param url resource to access + * @param flags flags which control how the resource indicated by url + * is to be opened + * @param int_cb an interrupt callback to be used at the protocols level + * @param options A dictionary filled with protocol-private options. On return + * this parameter will be destroyed and replaced with a dict containing options + * that were not found. May be NULL. + * @return >= 0 in case of success, a negative value corresponding to an + * AVERROR code in case of failure + */ +int avio_open2(AVIOContext **s, const char *url, int flags, + const AVIOInterruptCB *int_cb, AVDictionary **options); + +/** + * Close the resource accessed by the AVIOContext s and free it. + * This function can only be used if s was opened by avio_open(). + * + * The internal buffer is automatically flushed before closing the + * resource. + * + * @return 0 on success, an AVERROR < 0 on error. + * @see avio_closep + */ +int avio_close(AVIOContext *s); + +/** + * Close the resource accessed by the AVIOContext *s, free it + * and set the pointer pointing to it to NULL. + * This function can only be used if s was opened by avio_open(). + * + * The internal buffer is automatically flushed before closing the + * resource. + * + * @return 0 on success, an AVERROR < 0 on error. + * @see avio_close + */ +int avio_closep(AVIOContext **s); + + +/** + * Open a write only memory stream. + * + * @param s new IO context + * @return zero if no error. + */ +int avio_open_dyn_buf(AVIOContext **s); + +/** + * Return the written size and a pointer to the buffer. + * The AVIOContext stream is left intact. + * The buffer must NOT be freed. + * No padding is added to the buffer. + * + * @param s IO context + * @param pbuffer pointer to a byte buffer + * @return the length of the byte buffer + */ +int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer); + +/** + * Return the written size and a pointer to the buffer. The buffer + * must be freed with av_free(). + * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer. + * + * @param s IO context + * @param pbuffer pointer to a byte buffer + * @return the length of the byte buffer + */ +int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer); + +/** + * Iterate through names of available protocols. + * + * @param opaque A private pointer representing current protocol. + * It must be a pointer to NULL on first iteration and will + * be updated by successive calls to avio_enum_protocols. + * @param output If set to 1, iterate over output protocols, + * otherwise over input protocols. + * + * @return A static string containing the name of current protocol or NULL + */ +const char *avio_enum_protocols(void **opaque, int output); + +/** + * Get AVClass by names of available protocols. + * + * @return A AVClass of input protocol name or NULL + */ +const AVClass *avio_protocol_get_class(const char *name); + +/** + * Pause and resume playing - only meaningful if using a network streaming + * protocol (e.g. MMS). + * + * @param h IO context from which to call the read_pause function pointer + * @param pause 1 for pause, 0 for resume + */ +int avio_pause(AVIOContext *h, int pause); + +/** + * Seek to a given timestamp relative to some component stream. + * Only meaningful if using a network streaming protocol (e.g. MMS.). + * + * @param h IO context from which to call the seek function pointers + * @param stream_index The stream index that the timestamp is relative to. + * If stream_index is (-1) the timestamp should be in AV_TIME_BASE + * units from the beginning of the presentation. + * If a stream_index >= 0 is used and the protocol does not support + * seeking based on component streams, the call will fail. + * @param timestamp timestamp in AVStream.time_base units + * or if there is no stream specified then in AV_TIME_BASE units. + * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE + * and AVSEEK_FLAG_ANY. The protocol may silently ignore + * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will + * fail if used and not supported. + * @return >= 0 on success + * @see AVInputFormat::read_seek + */ +int64_t avio_seek_time(AVIOContext *h, int stream_index, + int64_t timestamp, int flags); + +/* Avoid a warning. The header can not be included because it breaks c++. */ +struct AVBPrint; + +/** + * Read contents of h into print buffer, up to max_size bytes, or up to EOF. + * + * @return 0 for success (max_size bytes read or EOF reached), negative error + * code otherwise + */ +int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size); + +/** + * Accept and allocate a client context on a server context. + * @param s the server context + * @param c the client context, must be unallocated + * @return >= 0 on success or a negative value corresponding + * to an AVERROR on failure + */ +int avio_accept(AVIOContext *s, AVIOContext **c); + +/** + * Perform one step of the protocol handshake to accept a new client. + * This function must be called on a client returned by avio_accept() before + * using it as a read/write context. + * It is separate from avio_accept() because it may block. + * A step of the handshake is defined by places where the application may + * decide to change the proceedings. + * For example, on a protocol with a request header and a reply header, each + * one can constitute a step because the application may use the parameters + * from the request to change parameters in the reply; or each individual + * chunk of the request can constitute a step. + * If the handshake is already finished, avio_handshake() does nothing and + * returns 0 immediately. + * + * @param c the client context to perform the handshake on + * @return 0 on a complete and successful handshake + * > 0 if the handshake progressed, but is not complete + * < 0 for an AVERROR code + */ +int avio_handshake(AVIOContext *c); +#endif /* AVFORMAT_AVIO_H */ |