ffmpeg/libavformat/avio.h

526 lines
18 KiB
C

/*
* 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
* unbuffered I/O operations
*
* @warning This file has to be considered an internal but installed
* header, so it should not be directly included in your projects.
*/
#include <stdint.h>
#include "libavutil/common.h"
/* unbuffered I/O */
/**
* URL Context.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(URLContext) must not be used outside libav*.
*/
typedef struct URLContext {
#if LIBAVFORMAT_VERSION_MAJOR >= 53
const AVClass *av_class; ///< information for av_log(). Set by url_open().
#endif
struct URLProtocol *prot;
int flags;
int is_streamed; /**< true if streamed (no seek possible), default = false */
int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
void *priv_data;
char *filename; /**< specified URL */
} URLContext;
typedef struct URLPollEntry {
URLContext *handle;
int events;
int revents;
} URLPollEntry;
#define URL_RDONLY 0
#define URL_WRONLY 1
#define URL_RDWR 2
typedef int URLInterruptCB(void);
/**
* Creates an URLContext for accessing to the resource indicated by
* url, and opens it using the URLProtocol up.
*
* @param puc pointer to the location where, in case of success, the
* function puts the pointer to the created URLContext
* @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 url_open_protocol (URLContext **puc, struct URLProtocol *up,
const char *url, int flags);
/**
* Creates an URLContext for accessing to the resource indicated by
* url, and opens it.
*
* @param puc pointer to the location where, in case of success, the
* function puts the pointer to the created URLContext
* @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 url_open(URLContext **h, const char *url, int flags);
/**
* Reads up to size bytes from the resource accessed by h, and stores
* the read bytes in buf.
*
* @return The number of bytes actually read, or a negative value
* corresponding to an AVERROR code in case of error. A value of zero
* indicates that it is not possible to read more from the accessed
* resource (except if the value of the size argument is also zero).
*/
int url_read(URLContext *h, unsigned char *buf, int size);
/**
* Read as many bytes as possible (up to size), calling the
* read function multiple times if necessary.
* Will also retry if the read function returns AVERROR(EAGAIN).
* This makes special short-read handling in applications
* unnecessary, if the return value is < size then it is
* certain there was either an error or the end of file was reached.
*/
int url_read_complete(URLContext *h, unsigned char *buf, int size);
int url_write(URLContext *h, unsigned char *buf, int size);
/**
* Changes the position that will be used by the next read/write
* operation on the resource accessed by h.
*
* @param pos specifies the new position to set
* @param whence specifies how pos should be interpreted, it must be
* one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
* current position), SEEK_END (seek from the end), or AVSEEK_SIZE
* (return the filesize of the requested resource, pos is ignored).
* @return a negative value corresponding to an AVERROR code in case
* of failure, or the resulting file position, measured in bytes from
* the beginning of the file. You can use this feature together with
* SEEK_CUR to read the current file position.
*/
int64_t url_seek(URLContext *h, int64_t pos, int whence);
/**
* Closes the resource accessed by the URLContext h, and frees the
* memory used by it.
*
* @return a negative value if an error condition occurred, 0
* otherwise
*/
int url_close(URLContext *h);
/**
* Returns a non-zero value if the resource indicated by url
* exists, 0 otherwise.
*/
int url_exist(const char *url);
int64_t url_filesize(URLContext *h);
/**
* Return the file descriptor associated with this URL. For RTP, this
* will return only the RTP file descriptor, not the RTCP file descriptor.
* To get both, use rtp_get_file_handles().
*
* @return the file descriptor associated with this URL, or <0 on error.
*/
int url_get_file_handle(URLContext *h);
/**
* Return the maximum packet size associated to packetized file
* handle. If the file is not packetized (stream like HTTP or file on
* disk), then 0 is returned.
*
* @param h file handle
* @return maximum packet size in bytes
*/
int url_get_max_packet_size(URLContext *h);
void url_get_filename(URLContext *h, char *buf, int buf_size);
/**
* The callback is called in blocking functions to test regulary if
* asynchronous interruption is needed. AVERROR(EINTR) is returned
* in this case by the interrupted function. 'NULL' means no interrupt
* callback is given.
*/
void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
/* not implemented */
int url_poll(URLPollEntry *poll_table, int n, int timeout);
/**
* Pause and resume playing - only meaningful if using a network streaming
* protocol (e.g. MMS).
* @param pause 1 for pause, 0 for resume
*/
int av_url_read_pause(URLContext *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 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 with ENOTSUP.
* @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 with ENOTSUP if used and not supported.
* @return >= 0 on success
* @see AVInputFormat::read_seek
*/
int64_t av_url_read_seek(URLContext *h, int stream_index,
int64_t timestamp, int flags);
/**
* Passing 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
/**
* Oring this flag as into the "whence" parameter to a seek function causes it to
* seek by any means (like reopening and linear reading) or other normally unreasonble
* means that can be extreemly slow.
* This may be ignored by the seek code.
*/
#define AVSEEK_FORCE 0x20000
typedef struct URLProtocol {
const char *name;
int (*url_open)(URLContext *h, const char *url, int flags);
int (*url_read)(URLContext *h, unsigned char *buf, int size);
int (*url_write)(URLContext *h, unsigned char *buf, int size);
int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
int (*url_close)(URLContext *h);
struct URLProtocol *next;
int (*url_read_pause)(URLContext *h, int pause);
int64_t (*url_read_seek)(URLContext *h, int stream_index,
int64_t timestamp, int flags);
int (*url_get_file_handle)(URLContext *h);
} URLProtocol;
#if LIBAVFORMAT_VERSION_MAJOR < 53
extern URLProtocol *first_protocol;
#endif
extern URLInterruptCB *url_interrupt_cb;
/**
* If protocol is NULL, returns the first registered protocol,
* if protocol is non-NULL, returns the next registered protocol after protocol,
* or NULL if protocol is the last one.
*/
URLProtocol *av_protocol_next(URLProtocol *p);
#if LIBAVFORMAT_VERSION_MAJOR < 53
/**
* @deprecated Use av_register_protocol() instead.
*/
attribute_deprecated int register_protocol(URLProtocol *protocol);
#endif
/**
* Registers the URLProtocol protocol.
*/
int av_register_protocol(URLProtocol *protocol);
/**
* Bytestream IO Context.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(ByteIOContext) must not be used outside libav*.
*/
typedef struct {
unsigned char *buffer;
int buffer_size;
unsigned char *buf_ptr, *buf_end;
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);
int64_t pos; /**< position in the file of the current buffer */
int must_flush; /**< true if the next seek should flush */
int eof_reached; /**< true if eof reached */
int write_flag; /**< true if open for writing */
int is_streamed;
int max_packet_size;
unsigned long checksum;
unsigned char *checksum_ptr;
unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
int error; ///< contains the error code or 0 if no error happened
int (*read_pause)(void *opaque, int pause);
int64_t (*read_seek)(void *opaque, int stream_index,
int64_t timestamp, int flags);
} ByteIOContext;
int init_put_byte(ByteIOContext *s,
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));
ByteIOContext *av_alloc_put_byte(
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));
void put_byte(ByteIOContext *s, int b);
void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
void put_le64(ByteIOContext *s, uint64_t val);
void put_be64(ByteIOContext *s, uint64_t val);
void put_le32(ByteIOContext *s, unsigned int val);
void put_be32(ByteIOContext *s, unsigned int val);
void put_le24(ByteIOContext *s, unsigned int val);
void put_be24(ByteIOContext *s, unsigned int val);
void put_le16(ByteIOContext *s, unsigned int val);
void put_be16(ByteIOContext *s, unsigned int val);
void put_tag(ByteIOContext *s, const char *tag);
void put_strz(ByteIOContext *s, const char *buf);
/**
* fseek() equivalent for ByteIOContext.
* @return new position or AVERROR.
*/
int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
/**
* Skip given number of bytes forward.
* @param offset number of bytes
*/
void url_fskip(ByteIOContext *s, int64_t offset);
/**
* ftell() equivalent for ByteIOContext.
* @return position or AVERROR.
*/
int64_t url_ftell(ByteIOContext *s);
/**
* Gets the filesize.
* @return filesize or AVERROR
*/
int64_t url_fsize(ByteIOContext *s);
/**
* feof() equivalent for ByteIOContext.
* @return non zero if and only if end of file
*/
int url_feof(ByteIOContext *s);
int url_ferror(ByteIOContext *s);
int av_url_read_fpause(ByteIOContext *h, int pause);
int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
int64_t timestamp, int flags);
#define URL_EOF (-1)
/** @note return URL_EOF (-1) if EOF */
int url_fgetc(ByteIOContext *s);
/** @warning currently size is limited */
#ifdef __GNUC__
int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
#else
int url_fprintf(ByteIOContext *s, const char *fmt, ...);
#endif
/** @note unlike fgets, the EOL character is not returned and a whole
line is parsed. return NULL if first char read was EOF */
char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
void put_flush_packet(ByteIOContext *s);
/**
* Reads size bytes from ByteIOContext into buf.
* @return number of bytes read or AVERROR
*/
int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
/**
* Reads size bytes from ByteIOContext into buf.
* This reads at most 1 packet. If that is not enough fewer bytes will be
* returned.
* @return number of bytes read or AVERROR
*/
int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
/** @note return 0 if EOF, so you cannot use it if EOF handling is
necessary */
int get_byte(ByteIOContext *s);
unsigned int get_le24(ByteIOContext *s);
unsigned int get_le32(ByteIOContext *s);
uint64_t get_le64(ByteIOContext *s);
unsigned int get_le16(ByteIOContext *s);
char *get_strz(ByteIOContext *s, char *buf, int maxlen);
unsigned int get_be16(ByteIOContext *s);
unsigned int get_be24(ByteIOContext *s);
unsigned int get_be32(ByteIOContext *s);
uint64_t get_be64(ByteIOContext *s);
uint64_t ff_get_v(ByteIOContext *bc);
static inline int url_is_streamed(ByteIOContext *s)
{
return s->is_streamed;
}
/**
* Creates and initializes a ByteIOContext for accessing the
* resource referenced by the URLContext h.
* @note When the URLContext h has been opened in read+write mode, the
* ByteIOContext can be used only for writing.
*
* @param s Used to return the pointer to the created ByteIOContext.
* In case of failure the pointed to value is set to NULL.
* @return 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int url_fdopen(ByteIOContext **s, URLContext *h);
/** @warning must be called before any I/O */
int url_setbufsize(ByteIOContext *s, int buf_size);
#if LIBAVFORMAT_VERSION_MAJOR < 53
/** Reset the buffer for reading or writing.
* @note Will drop any data currently in the buffer without transmitting it.
* @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
* to set up the buffer for writing. */
int url_resetbuf(ByteIOContext *s, int flags);
#endif
/**
* Rewinds the ByteIOContext using the specified buffer containing the first buf_size bytes of the file.
* Used after probing to avoid seeking.
* Joins buf and s->buffer, taking any overlap into consideration.
* @note s->buffer must overlap with buf or they can't be joined and the function fails
* @note This function is NOT part of the public API
*
* @param s The read-only ByteIOContext to rewind
* @param buf The probe buffer containing the first buf_size bytes of the file
* @param buf_size The size of buf
* @return 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size);
/**
* Creates and initializes a ByteIOContext for accessing the
* resource indicated by url.
* @note When the resource indicated by url has been opened in
* read+write mode, the ByteIOContext can be used only for writing.
*
* @param s Used to return the pointer to the created ByteIOContext.
* In case of failure the pointed to value is set to NULL.
* @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 url_fopen(ByteIOContext **s, const char *url, int flags);
int url_fclose(ByteIOContext *s);
URLContext *url_fileno(ByteIOContext *s);
/**
* Return the maximum packet size associated to packetized buffered file
* handle. If the file is not packetized (stream like http or file on
* disk), then 0 is returned.
*
* @param s buffered file handle
* @return maximum packet size in bytes
*/
int url_fget_max_packet_size(ByteIOContext *s);
int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
/** return the written or read size */
int url_close_buf(ByteIOContext *s);
/**
* Open a write only memory stream.
*
* @param s new IO context
* @return zero if no error.
*/
int url_open_dyn_buf(ByteIOContext **s);
/**
* Open a write only packetized memory stream with a maximum packet
* size of 'max_packet_size'. The stream is stored in a memory buffer
* with a big endian 4 byte header giving the packet size in bytes.
*
* @param s new IO context
* @param max_packet_size maximum packet size (must be > 0)
* @return zero if no error.
*/
int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
/**
* Return the written size and a pointer to the buffer. The buffer
* must be freed with av_free().
* @param s IO context
* @param pbuffer pointer to a byte buffer
* @return the length of the byte buffer
*/
int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
unsigned int len);
unsigned long get_checksum(ByteIOContext *s);
void init_checksum(ByteIOContext *s,
unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
unsigned long checksum);
/* udp.c */
int udp_set_remote_url(URLContext *h, const char *uri);
int udp_get_local_port(URLContext *h);
#if (LIBAVFORMAT_VERSION_MAJOR <= 52)
int udp_get_file_handle(URLContext *h);
#endif
#endif /* AVFORMAT_AVIO_H */