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 AVFifoBuffer *av_fifo_alloc(unsigned int size)
  26 {
  27     AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
  28     if(!f)
  29         return NULL;
  30     f->buffer = av_malloc(size);
  31     f->end = f->buffer + size;
  32     av_fifo_reset(f);
  33     if (!f->buffer)
  34         av_freep(&f);
  35     return f;
  36 }
  37
  38 void av_fifo_free(AVFifoBuffer *f)
  39 {
  40     if(f){
  41         av_free(f->buffer);
  42         av_free(f);
  43     }
  44 }
  45
  46 void av_fifo_reset(AVFifoBuffer *f)
  47 {
  48     f->wptr = f->rptr = f->buffer;
  49     f->wndx = f->rndx = 0;
  50 }
  51
  52 int av_fifo_size(AVFifoBuffer *f)
  53 {
  54     return (uint32_t)(f->wndx - f->rndx);
  55 }
  56
  57 int av_fifo_space(AVFifoBuffer *f)
  58 {
  59     return f->end - f->buffer - av_fifo_size(f);
  60 }
  61
  62 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {
  63     unsigned int old_size= f->end - f->buffer;
  64
  65     if(old_size < new_size){
  66         int len= av_fifo_size(f);
  67         AVFifoBuffer *f2= av_fifo_alloc(new_size);
  68
  69         if (!f2)
  70             return -1;
  71         av_fifo_generic_read(f, f2->buffer, len, NULL);
  72         f2->wptr += len;
  73         f2->wndx += len;
  74         av_free(f->buffer);
  75         *f= *f2;
  76         av_free(f2);
  77     }
  78     return 0;
  79 }
  80
  81 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
  82 {
  83     int total = size;
  84     do {
  85         int len = FFMIN(f->end - f->wptr, size);
  86         if(func) {
  87             if(func(src, f->wptr, len) <= 0)
  88                 break;
  89         } else {
  90             memcpy(f->wptr, src, len);
  91             src = (uint8_t*)src + len;
  92         }
  93 // Write memory barrier needed for SMP here in theory
  94         f->wptr += len;
  95         if (f->wptr >= f->end)
  96             f->wptr = f->buffer;
  97         f->wndx += len;
  98         size -= len;
  99     } while (size > 0);
 100     return total - size;
 101 }
 102
 103
 104 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
 105 {
 106 // Read memory barrier needed for SMP here in theory
 107     do {
 108         int len = FFMIN(f->end - f->rptr, buf_size);
 109         if(func) func(dest, f->rptr, len);
 110         else{
 111             memcpy(dest, f->rptr, len);
 112             dest = (uint8_t*)dest + len;
 113         }
 114 // memory barrier needed for SMP here in theory
 115         av_fifo_drain(f, len);
 116         buf_size -= len;
 117     } while (buf_size > 0);
 118     return 0;
 119 }
 120
 121 /** Discard data from the FIFO. */
 122 void av_fifo_drain(AVFifoBuffer *f, int size)
 123 {
 124     f->rptr += size;
 125     if (f->rptr >= f->end)
 126         f->rptr -= f->end - f->buffer;
 127     f->rndx += size;
 128 }