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 FIFO_H
  25 #define FIFO_H
  26
  27 typedef struct AVFifoBuffer {
  28     uint8_t *buffer;
  29     uint8_t *rptr, *wptr, *end;
  30 } AVFifoBuffer;
  31
  32 /**
  33  * Initializes a FIFO *.
  34  * @param *f FIFO buffer
  35  * @param size of FIFO
  36  * @return <0 for failure >=0 otherwise
  37  */
  38 int av_fifo_init(AVFifoBuffer *f, int size);
  39
  40 /**
  41  * Frees a FIFO *.
  42  * @param *f FIFO buffer
  43  */
  44 void av_fifo_free(AVFifoBuffer *f);
  45
  46 /**
  47  * Returns the size of a FIFO *.
  48  * @param *f FIFO buffer
  49  * @return size
  50  */
  51 int av_fifo_size(AVFifoBuffer *f);
  52
  53 /**
  54  * Reads the data from the FIFO *.
  55  * @param *f FIFO buffer
  56  * @param *buf data destination
  57  * @param buf_size data size
  58  * @return -1 if not enough data
  59  */
  60 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size);
  61
  62 /**
  63  * Reads the data from the FIFO *.
  64  * @param *f FIFO buffer
  65  * @param buf_size data size
  66  * @param *func generic read function
  67  * @param *dest data destination
  68  * @return -1 if not enough data
  69  */
  70 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
  71
  72 /**
  73  * Writes the data in the FIFO *.
  74  * @param *f FIFO buffer
  75  * @param *buf data source
  76  * @param size data size
  77  */
  78 void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
  79
  80 /**
  81  * Resizes the FIFO *.
  82  * @param *f FIFO buffer
  83  * @param size data size
  84  */
  85 void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
  86
  87 /**
  88  * Discards the data from the FIFO *.
  89  * @param *f FIFO buffer
  90  * @param size data size
  91  */
  92 void av_fifo_drain(AVFifoBuffer *f, int size);
  93
  94 /**
  95  * Returns a pointer with circular offset from FIFO's read pointer.
  96  * @param *f FIFO buffer
  97  * @param offs offset
  98  * @return ptr=rptr+offs if rptr+offs<end else rptr+offs -(end-begin)
  99  */
 100 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
 101 {
 102     uint8_t *ptr = f->rptr + offs;
 103     if (ptr >= f->end)
 104         ptr -= f->end - f->buffer;
 105     return *ptr;
 106 }
 107 #endif /* FIFO_H */