/*

 * copyright (c) 2001 Fabrice Bellard

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; 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 "libavutil/common.h"

#include "libavutil/dict.h"

#include "libavutil/log.h"

#include "libavformat/version.h"

#define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */

/**

 * 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;

/**

 * 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(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;

    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 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 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 */

    /**

     * 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;

} AVIOContext;

/* unbuffered I/O */

/**

 * 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);

/**

 * Allocate and initialize an AVIOContext for buffered I/O. It must be later

 * freed with av_free().

 *

 * @param buffer Memory block for input/output operations via AVIOContext.

 *        The buffer must be allocated with av_malloc() and friends.

 * @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.

 * @param write_packet A function for writing the buffer contents, may be NULL.

 * @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));

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.

 * @return number of bytes written.

 */

int avio_put_str16le(AVIOContext *s, const char *str);

/**

 * 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

/**

 * 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.

 */

static av_always_inline int64_t avio_skip(AVIOContext *s, int64_t offset)

{

    return avio_seek(s, offset, SEEK_CUR);

}

/**

 * 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);

/** @warning currently size is limited */

int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);

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);

/**

 * @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

/**

 * 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 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 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 buffer

 * must be freed with av_free().

 * Padding of FF_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);

/**

 * Pause and resume playing - only meaningful if using a network streaming

 * protocol (e.g. MMS).

 * @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 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 avio_seek_time(AVIOContext *h, int stream_index,

                       int64_t timestamp, int flags);

#endif /* AVFORMAT_AVIO_H */