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 size of FIFO
  40  * @return AVFifoBuffer or NULL if mem allocation failure
  41  */
  42 AVFifoBuffer *av_fifo_alloc(unsigned int size);
  43
  44 /**
  45  * Frees an AVFifoBuffer.
  46  * @param *f AVFifoBuffer to free
  47  */
  48 void av_fifo_free(AVFifoBuffer *f);
  49
  50 /**
  51  * Returns the amount of data in bytes in the AVFifoBuffer, that is the
  52  * amount of data you can read from it.
  53  * @param *f AVFifoBuffer to read from
  54  * @return size
  55  */
  56 int av_fifo_size(AVFifoBuffer *f);
  57
  58 /**
  59  * Feeds data from an AVFifoBuffer to a user-supplied callback.
  60  * @param *f AVFifoBuffer to read from
  61  * @param buf_size number of bytes to read
  62  * @param *func generic read function
  63  * @param *dest data destination
  64  */
  65 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
  66
  67 #if LIBAVUTIL_VERSION_MAJOR < 50
  68 /**
  69  * Writes data into an AVFifoBuffer.
  70  * @param *f AVFifoBuffer to write to
  71  * @param *buf data source
  72  * @param size data size
  73  */
  74 attribute_deprecated void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
  75 #endif
  76
  77 /**
  78  * Feeds data from a user-supplied callback to an AVFifoBuffer.
  79  * @param *f AVFifoBuffer to write to
  80  * @param *src data source
  81  * @param size number of bytes to write
  82  * @param *func generic write function; the first parameter is src,
  83  * the second is dest_buf, the third is dest_buf_size.
  84  * func must return the number of bytes written to dest_buf, or <= 0 to
  85  * indicate no more data available to write.
  86  * If func is NULL, src is interpreted as a simple byte array for source data.
  87  * @return the number of bytes written to the FIFO
  88  */
  89 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
  90
  91 #if LIBAVUTIL_VERSION_MAJOR < 50
  92 /**
  93  * Resizes an AVFifoBuffer.
  94  * @param *f AVFifoBuffer to resize
  95  * @param size new AVFifoBuffer size in bytes
  96  * @see av_fifo_realloc2()
  97  */
  98 attribute_deprecated void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
  99 #endif
 100
 101 /**
 102  * Resizes an AVFifoBuffer.
 103  * @param *f AVFifoBuffer to resize
 104  * @param size new AVFifoBuffer size in bytes
 105  * @return <0 for failure, >=0 otherwise
 106  */
 107 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
 108
 109 /**
 110  * Reads and discards the specified amount of data from an AVFifoBuffer.
 111  * @param *f AVFifoBuffer to read from
 112  * @param size amount of data to read in bytes
 113  */
 114 void av_fifo_drain(AVFifoBuffer *f, int size);
 115
 116 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
 117 {
 118     uint8_t *ptr = f->rptr + offs;
 119     if (ptr >= f->end)
 120         ptr -= f->end - f->buffer;
 121     return *ptr;
 122 }
 123 #endif /* AVUTIL_FIFO_H */