/*
  * 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_INTERNAL_H
 #define AVFORMAT_AVIO_INTERNAL_H
 
 #include "avio.h"

 #include "url.h"

 #include "libavutil/log.h"
 

 extern const AVClass ff_avio_class;

 int ffio_init_context(AVIOContext *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));
 
 

 /**

  * Read size bytes from AVIOContext, returning a pointer.
  * Note that the data pointed at by the returned pointer is only
  * valid until the next call that references the same IO context.
  * @param s IO context
  * @param buf pointer to buffer into which to assemble the requested
  *    data if it is not available in contiguous addresses in the
  *    underlying buffer
  * @param size number of bytes requested
  * @param data address at which to store pointer: this will be a
  *    a direct pointer into the underlying buffer if the requested
  *    number of bytes are available at contiguous addresses, otherwise
  *    will be a copy of buf
  * @return number of bytes read or AVERROR
  */

 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data);

 void ffio_fill(AVIOContext *s, int b, int count);
 

 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
 {
     avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
 }

 /**
  * Rewind the AVIOContext 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
  *
  * @param s The read-only AVIOContext 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 ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size);

 uint64_t ffio_read_varlen(AVIOContext *bc);
 

 /**
  * Read size bytes from AVIOContext into buf.
  * Check that exactly size bytes have been read.
  * @return number of bytes read or AVERROR
  */
 int ffio_read_size(AVIOContext *s, unsigned char *buf, int size);
 

 /** @warning must be called before any I/O */
 int ffio_set_buf_size(AVIOContext *s, int buf_size);
 

 /**
  * Ensures that the requested seekback buffer size will be available
  *
  * Will ensure that when reading sequentially up to buf_size, seeking
  * within the current pos and pos+buf_size is possible.

  * Once the stream position moves outside this window this guarantee is lost.

  */

 int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size);

 int ffio_limit(AVIOContext *s, int size);
 

 void ffio_init_checksum(AVIOContext *s,
                         unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
                         unsigned long checksum);

 unsigned long ffio_get_checksum(AVIOContext *s);

 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
                                     unsigned int len);

 unsigned long ff_crcEDB88320_update(unsigned long checksum, const uint8_t *buf,
                                     unsigned int len);

 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
                                 unsigned int len);

 /**
  * 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 ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
 

 /**
  * Create and initialize a AVIOContext for accessing the
  * resource referenced by the URLContext h.
  * @note When the URLContext h 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.

  * @return >= 0 in case of success, a negative value corresponding to an

  * AVERROR code in case of failure
  */
 int ffio_fdopen(AVIOContext **s, URLContext *h);
 

 /**

  * Return the URLContext associated with the AVIOContext
  *
  * @param s IO context
  * @return pointer to URLContext or NULL.
  */
 URLContext *ffio_geturlcontext(AVIOContext *s);
 
 /**

  * Open a write-only fake memory stream. The written data is not stored
  * anywhere - this is only used for measuring the amount of data
  * written.
  *
  * @param s new IO context
  * @return zero if no error.
  */
 int ffio_open_null_buf(AVIOContext **s);
 

 int ffio_open_whitelist(AVIOContext **s, const char *url, int flags,
                          const AVIOInterruptCB *int_cb, AVDictionary **options,

                          const char *whitelist, const char *blacklist);

 /**
  * Close a null buffer.
  *
  * @param s an IO context opened by ffio_open_null_buf
  * @return the number of bytes written to the null buffer
  */
 int ffio_close_null_buf(AVIOContext *s);
 

 /**
  * Free a dynamic buffer.
  *
  * @param s a pointer to an IO context opened by avio_open_dyn_buf()
  */
 void ffio_free_dyn_buf(AVIOContext **s);
 

 #endif /* AVFORMAT_AVIO_INTERNAL_H */