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_realloc2(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= av_fifo_alloc(new_size);
  63
  64         if (!f2)
  65             return -1;
  66         av_fifo_generic_read(f, f2->buffer, len, NULL);
  67         f2->wptr += len;
  68         f2->wndx += len;
  69         av_free(f->buffer);
  70         *f= *f2;
  71         av_free(f2);
  72     }
  73     return 0;
  74 }
  75
  76 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
  77 {
  78     int total = size;
  79     do {
  80         int len = FFMIN(f->end - f->wptr, size);
  81         if(func) {
  82             if(func(src, f->wptr, len) <= 0)
  83                 break;
  84         } else {
  85             memcpy(f->wptr, src, len);
  86             src = (uint8_t*)src + len;
  87         }
  88 // Write memory barrier needed for SMP here in theory
  89         f->wptr += len;
  90         if (f->wptr >= f->end)
  91             f->wptr = f->buffer;
  92         f->wndx += len;
  93         size -= len;
  94     } while (size > 0);
  95     return total - size;
  96 }
  97
  98
  99 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
 100 {
 101 // Read memory barrier needed for SMP here in theory
 102     do {
 103         int len = FFMIN(f->end - f->rptr, buf_size);
 104         if(func) func(dest, f->rptr, len);
 105         else{
 106             memcpy(dest, f->rptr, len);
 107             dest = (uint8_t*)dest + len;
 108         }
 109 // memory barrier needed for SMP here in theory
 110         av_fifo_drain(f, len);
 111         buf_size -= len;
 112     } while (buf_size > 0);
 113     return 0;
 114 }
 115
 116 /** Discard data from the FIFO. */
 117 void av_fifo_drain(AVFifoBuffer *f, int size)
 118 {
 119     f->rptr += size;
 120     if (f->rptr >= f->end)
 121         f->rptr -= f->end - f->buffer;
 122     f->rndx += size;
 123 }