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 FFMPEG_FIFO_H
  25 #define FFMPEG_FIFO_H
  26
  27 #include <stdint.h>
  28
  29 typedef struct AVFifoBuffer {
  30     uint8_t *buffer;
  31     uint8_t *rptr, *wptr, *end;
  32 } AVFifoBuffer;
  33
  34 /**
  35  * Initializes an AVFifoBuffer.
  36  * @param *f AVFifoBuffer to initialize
  37  * @param size of FIFO
  38  * @return <0 for failure >=0 otherwise
  39  */
  40 int av_fifo_init(AVFifoBuffer *f, int size);
  41
  42 /**
  43  * Frees an AVFifoBuffer.
  44  * @param *f AVFifoBuffer to free
  45  */
  46 void av_fifo_free(AVFifoBuffer *f);
  47
  48 /**
  49  * Returns the amount of data in bytes in the AVFifoBuffer, that is the
  50  * amount of data you can read from it.
  51  * @param *f AVFifoBuffer to read from
  52  * @return size
  53  */
  54 int av_fifo_size(AVFifoBuffer *f);
  55
  56 /**
  57  * Reads data from an AVFifoBuffer.
  58  * @param *f AVFifoBuffer to read from
  59  * @param *buf data destination
  60  * @param buf_size number of bytes to read
  61  */
  62 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size);
  63
  64 /**
  65  * Feeds data from an AVFifoBuffer to a user supplied callback.
  66  * @param *f AVFifoBuffer to read from
  67  * @param buf_size number of bytes to read
  68  * @param *func generic read function
  69  * @param *dest data destination
  70  */
  71 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
  72
  73 /**
  74  * Writes data into an AVFifoBuffer.
  75  * @param *f AVFifoBuffer to write to
  76  * @param *buf data source
  77  * @param size data size
  78  */
  79 attribute_deprecated void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
  80
  81 /**
  82  * Feeds data from a user supplied callback to an AVFifoBuffer.
  83  * @param *f AVFifoBuffer to write to
  84  * @param *buf data source
  85  * @param size number of bytes to write
  86  * @param *func generic write function. First parameter is buf,
  87  * second is dest_buf, third is dest_buf_size.
  88  * func must return the number of bytes written to dest_buf, or <= 0 to
  89  * indicate no more data available to write.
  90  * If func is NULL, buf is interpreted as a simple byte array for source data.
  91  * @return the number of bytes written to the fifo.
  92  */
  93 int av_fifo_generic_write(AVFifoBuffer *f, void *buf, int size, int (*func)(void*, void*, int));
  94
  95 /**
  96  * Resizes an AVFifoBuffer.
  97  * @param *f AVFifoBuffer to resize
  98  * @param size new AVFifoBuffer size in bytes
  99  */
 100 void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
 101
 102 /**
 103  * Reads and discards the specified amount of data from an AVFifoBuffer.
 104  * @param *f AVFifoBuffer to read from
 105  * @param size amount of data to read in bytes
 106  */
 107 void av_fifo_drain(AVFifoBuffer *f, int size);
 108
 109 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
 110 {
 111     uint8_t *ptr = f->rptr + offs;
 112     if (ptr >= f->end)
 113         ptr -= f->end - f->buffer;
 114     return *ptr;
 115 }
 116 #endif /* FFMPEG_FIFO_H */