libavformat/avio_internal.h

   1 /*
   2  *
   3  * This file is part of Libav.
   4  *
   5  * Libav is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * Libav is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with Libav; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #ifndef AVFORMAT_AVIO_INTERNAL_H
  21 #define AVFORMAT_AVIO_INTERNAL_H
  22
  23 #include "avio.h"
  24 #include "url.h"
  25
  26 #include "libavutil/log.h"
  27
  28 extern const AVClass ffio_url_class;
  29
  30 int ffio_init_context(AVIOContext *s,
  31                   unsigned char *buffer,
  32                   int buffer_size,
  33                   int write_flag,
  34                   void *opaque,
  35                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
  36                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
  37                   int64_t (*seek)(void *opaque, int64_t offset, int whence));
  38
  39
  40 /**
  41  * Read size bytes from AVIOContext into buf.
  42  * This reads at most 1 packet. If that is not enough fewer bytes will be
  43  * returned.
  44  * @return number of bytes read or AVERROR
  45  */
  46 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size);
  47
  48 void ffio_fill(AVIOContext *s, int b, int count);
  49
  50 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
  51 {
  52     avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
  53 }
  54
  55 /**
  56  * Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file.
  57  * Used after probing to avoid seeking.
  58  * Joins buf and s->buffer, taking any overlap into consideration.
  59  * @note s->buffer must overlap with buf or they can't be joined and the function fails
  60  *
  61  * @param s The read-only AVIOContext to rewind
  62  * @param buf The probe buffer containing the first buf_size bytes of the file
  63  * @param buf_size The size of buf
  64  * @return 0 in case of success, a negative value corresponding to an
  65  * AVERROR code in case of failure
  66  */
  67 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char *buf, int buf_size);
  68
  69 uint64_t ffio_read_varlen(AVIOContext *bc);
  70
  71 /** @warning must be called before any I/O */
  72 int ffio_set_buf_size(AVIOContext *s, int buf_size);
  73
  74 void ffio_init_checksum(AVIOContext *s,
  75                         unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
  76                         unsigned long checksum);
  77 unsigned long ffio_get_checksum(AVIOContext *s);
  78 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
  79                                     unsigned int len);
  80
  81 /**
  82  * Open a write only packetized memory stream with a maximum packet
  83  * size of 'max_packet_size'.  The stream is stored in a memory buffer
  84  * with a big-endian 4 byte header giving the packet size in bytes.
  85  *
  86  * @param s new IO context
  87  * @param max_packet_size maximum packet size (must be > 0)
  88  * @return zero if no error.
  89  */
  90 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
  91
  92 /**
  93  * Create and initialize a AVIOContext for accessing the
  94  * resource referenced by the URLContext h.
  95  * @note When the URLContext h has been opened in read+write mode, the
  96  * AVIOContext can be used only for writing.
  97  *
  98  * @param s Used to return the pointer to the created AVIOContext.
  99  * In case of failure the pointed to value is set to NULL.
 100  * @return 0 in case of success, a negative value corresponding to an
 101  * AVERROR code in case of failure
 102  */
 103 int ffio_fdopen(AVIOContext **s, URLContext *h);
 104
 105 #endif /* AVFORMAT_AVIO_INTERNAL_H */