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 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 "common.h"
  29
  30 typedef struct AVFifoBuffer {
  31     uint8_t *buffer;
  32     uint8_t *rptr, *wptr, *end;
  33 } AVFifoBuffer;
  34
  35 /**
  36  * Initializes an AVFifoBuffer.
  37  * @param *f AVFifoBuffer to initialize
  38  * @param size of FIFO
  39  * @return <0 for failure >=0 otherwise
  40  */
  41 int av_fifo_init(AVFifoBuffer *f, unsigned int size);
  42
  43 /**
  44  * Frees an AVFifoBuffer.
  45  * @param *f AVFifoBuffer to free
  46  */
  47 void av_fifo_free(AVFifoBuffer *f);
  48
  49 /**
  50  * Returns the amount of data in bytes in the AVFifoBuffer, that is the
  51  * amount of data you can read from it.
  52  * @param *f AVFifoBuffer to read from
  53  * @return size
  54  */
  55 int av_fifo_size(AVFifoBuffer *f);
  56
  57 /**
  58  * Reads data from an AVFifoBuffer.
  59  * @param *f AVFifoBuffer to read from
  60  * @param *buf data destination
  61  * @param buf_size number of bytes to read
  62  */
  63 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size);
  64
  65 /**
  66  * Feeds data from an AVFifoBuffer to a user supplied callback.
  67  * @param *f AVFifoBuffer to read from
  68  * @param buf_size number of bytes to read
  69  * @param *func generic read function
  70  * @param *dest data destination
  71  */
  72 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
  73
  74 /**
  75  * Writes data into an AVFifoBuffer.
  76  * @param *f AVFifoBuffer to write to
  77  * @param *buf data source
  78  * @param size data size
  79  */
  80 attribute_deprecated void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
  81
  82 /**
  83  * Feeds data from a user supplied callback to an AVFifoBuffer.
  84  * @param *f AVFifoBuffer to write to
  85  * @param *src data source
  86  * @param size number of bytes to write
  87  * @param *func generic write function. First parameter is src,
  88  * second is dest_buf, third is dest_buf_size.
  89  * func must return the number of bytes written to dest_buf, or <= 0 to
  90  * indicate no more data available to write.
  91  * If func is NULL, src is interpreted as a simple byte array for source data.
  92  * @return the number of bytes written to the fifo.
  93  */
  94 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
  95
  96 #if LIBAVUTIL_VERSION_MAJOR < 50
  97 /**
  98  * Resizes an AVFifoBuffer.
  99  * @param *f AVFifoBuffer to resize
 100  * @param size new AVFifoBuffer size in bytes
 101  * @see av_fifo_realloc2()
 102  */
 103 attribute_deprecated void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
 104 #endif
 105
 106 /**
 107  * Resizes an AVFifoBuffer.
 108  * @param *f AVFifoBuffer to resize
 109  * @param size new AVFifoBuffer size in bytes
 110  * @return <0 for failure >=0 otherwise
 111  */
 112 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
 113
 114 /**
 115  * Reads and discards the specified amount of data from an AVFifoBuffer.
 116  * @param *f AVFifoBuffer to read from
 117  * @param size amount of data to read in bytes
 118  */
 119 void av_fifo_drain(AVFifoBuffer *f, int size);
 120
 121 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
 122 {
 123     uint8_t *ptr = f->rptr + offs;
 124     if (ptr >= f->end)
 125         ptr -= f->end - f->buffer;
 126     return *ptr;
 127 }
 128 #endif /* AVUTIL_FIFO_H */