libavutil/fifo.c

   1 /*
   2  * A very simple circular buffer FIFO implementation
   3  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
   4  * Copyright (c) 2006 Roman Shaposhnik
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22 #include "common.h"
  23 #include "fifo.h"
  24
  25 int av_fifo_init(AVFifoBuffer *f, unsigned int size)
  26 {
  27     size= FFMAX(size, size+1);
  28     f->wptr = f->rptr =
  29     f->buffer = av_malloc(size);
  30     f->end = f->buffer + size;
  31     if (!f->buffer)
  32         return -1;
  33     return 0;
  34 }
  35
  36 void av_fifo_free(AVFifoBuffer *f)
  37 {
  38     av_free(f->buffer);
  39 }
  40
  41 int av_fifo_size(AVFifoBuffer *f)
  42 {
  43     int size = f->wptr - f->rptr;
  44     if (size < 0)
  45         size += f->end - f->buffer;
  46     return size;
  47 }
  48
  49 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size)
  50 {
  51     return av_fifo_generic_read(f, buf_size, NULL, buf);
  52 }
  53
  54 /**
  55  * Resizes a FIFO.
  56  */
  57 void av_fifo_realloc(AVFifoBuffer *f, unsigned int new_size) {
  58     unsigned int old_size= f->end - f->buffer;
  59
  60     if(old_size <= new_size){
  61         int len= av_fifo_size(f);
  62         AVFifoBuffer f2;
  63
  64         av_fifo_init(&f2, new_size);
  65         av_fifo_read(f, f2.buffer, len);
  66         f2.wptr += len;
  67         av_free(f->buffer);
  68         *f= f2;
  69     }
  70 }
  71
  72 void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size)
  73 {
  74     av_fifo_generic_write(f, (void *)buf, size, NULL);
  75 }
  76
  77 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
  78 {
  79     int total = size;
  80     do {
  81         int len = FFMIN(f->end - f->wptr, size);
  82         if(func) {
  83             if(func(src, f->wptr, len) <= 0)
  84                 break;
  85         } else {
  86             memcpy(f->wptr, src, len);
  87             src = (uint8_t*)src + len;
  88         }
  89         f->wptr += len;
  90         if (f->wptr >= f->end)
  91             f->wptr = f->buffer;
  92         size -= len;
  93     } while (size > 0);
  94     return total - size;
  95 }
  96
  97
  98 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest)
  99 {
 100     do {
 101         int len = FFMIN(f->end - f->rptr, buf_size);
 102         if(func) func(dest, f->rptr, len);
 103         else{
 104             memcpy(dest, f->rptr, len);
 105             dest = (uint8_t*)dest + len;
 106         }
 107         av_fifo_drain(f, len);
 108         buf_size -= len;
 109     } while (buf_size > 0);
 110     return 0;
 111 }
 112
 113 /** discard data from the fifo */
 114 void av_fifo_drain(AVFifoBuffer *f, int size)
 115 {
 116     f->rptr += size;
 117     if (f->rptr >= f->end)
 118         f->rptr -= f->end - f->buffer;
 119 }