libavutil/fifo.h

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 /**
  20  * @file libavutil/fifo.h
  21  * a very simple circular buffer FIFO implementation
  22  */
  23
  24 #ifndef AVUTIL_FIFO_H
  25 #define AVUTIL_FIFO_H
  26
  27 #include <stdint.h>
  28 #include "avutil.h"
  29 #include "common.h"
  30
  31 typedef struct AVFifoBuffer {
  32     uint8_t *buffer;
  33     uint8_t *rptr, *wptr, *end;
  34     uint32_t rndx, wndx;
  35 } AVFifoBuffer;
  36
  37 /**
  38  * Initializes an AVFifoBuffer.
  39  * @param *f AVFifoBuffer to initialize
  40  * @param size of FIFO
  41  * @return <0 for failure >=0 otherwise
  42  */
  43 int av_fifo_init(AVFifoBuffer *f, unsigned int size);
  44
  45 /**
  46  * Frees an AVFifoBuffer.
  47  * @param *f AVFifoBuffer to free
  48  */
  49 void av_fifo_free(AVFifoBuffer *f);
  50
  51 /**
  52  * Returns the amount of data in bytes in the AVFifoBuffer, that is the
  53  * amount of data you can read from it.
  54  * @param *f AVFifoBuffer to read from
  55  * @return size
  56  */
  57 int av_fifo_size(AVFifoBuffer *f);
  58
  59 /**
  60  * Reads data from an AVFifoBuffer.
  61  * @param *f AVFifoBuffer to read from
  62  * @param *buf data destination
  63  * @param buf_size number of bytes to read
  64  */
  65 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size);
  66
  67 /**
  68  * Feeds data from an AVFifoBuffer to a user-supplied callback.
  69  * @param *f AVFifoBuffer to read from
  70  * @param buf_size number of bytes to read
  71  * @param *func generic read function
  72  * @param *dest data destination
  73  */
  74 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
  75
  76 #if LIBAVUTIL_VERSION_MAJOR < 50
  77 /**
  78  * Writes data into an AVFifoBuffer.
  79  * @param *f AVFifoBuffer to write to
  80  * @param *buf data source
  81  * @param size data size
  82  */
  83 attribute_deprecated void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
  84 #endif
  85
  86 /**
  87  * Feeds data from a user-supplied callback to an AVFifoBuffer.
  88  * @param *f AVFifoBuffer to write to
  89  * @param *src data source
  90  * @param size number of bytes to write
  91  * @param *func generic write function; the first parameter is src,
  92  * the second is dest_buf, the third is dest_buf_size.
  93  * func must return the number of bytes written to dest_buf, or <= 0 to
  94  * indicate no more data available to write.
  95  * If func is NULL, src is interpreted as a simple byte array for source data.
  96  * @return the number of bytes written to the FIFO
  97  */
  98 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
  99
 100 #if LIBAVUTIL_VERSION_MAJOR < 50
 101 /**
 102  * Resizes an AVFifoBuffer.
 103  * @param *f AVFifoBuffer to resize
 104  * @param size new AVFifoBuffer size in bytes
 105  * @see av_fifo_realloc2()
 106  */
 107 attribute_deprecated void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
 108 #endif
 109
 110 /**
 111  * Resizes an AVFifoBuffer.
 112  * @param *f AVFifoBuffer to resize
 113  * @param size new AVFifoBuffer size in bytes
 114  * @return <0 for failure, >=0 otherwise
 115  */
 116 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
 117
 118 /**
 119  * Reads and discards the specified amount of data from an AVFifoBuffer.
 120  * @param *f AVFifoBuffer to read from
 121  * @param size amount of data to read in bytes
 122  */
 123 void av_fifo_drain(AVFifoBuffer *f, int size);
 124
 125 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
 126 {
 127     uint8_t *ptr = f->rptr + offs;
 128     if (ptr >= f->end)
 129         ptr -= f->end - f->buffer;
 130     return *ptr;
 131 }
 132 #endif /* AVUTIL_FIFO_H */