mirror of
https://git.ffmpeg.org/ffmpeg.git
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130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/*
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* a very simple circular buffer FIFO implementation
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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* Copyright (c) 2006 Roman Shaposhnik
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "common.h"
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#include "fifo.h"
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AVFifoBuffer *av_fifo_alloc(unsigned int size)
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{
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AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
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if(!f)
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return NULL;
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f->buffer = av_malloc(size);
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f->end = f->buffer + size;
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av_fifo_reset(f);
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if (!f->buffer)
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av_freep(&f);
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return f;
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}
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void av_fifo_free(AVFifoBuffer *f)
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{
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if(f){
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av_free(f->buffer);
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av_free(f);
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}
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}
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void av_fifo_reset(AVFifoBuffer *f)
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{
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f->wptr = f->rptr = f->buffer;
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f->wndx = f->rndx = 0;
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}
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int av_fifo_size(AVFifoBuffer *f)
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{
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return (uint32_t)(f->wndx - f->rndx);
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}
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int av_fifo_space(AVFifoBuffer *f)
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{
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return f->end - f->buffer - av_fifo_size(f);
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}
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int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {
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unsigned int old_size= f->end - f->buffer;
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if(old_size < new_size){
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int len= av_fifo_size(f);
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AVFifoBuffer *f2= av_fifo_alloc(new_size);
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if (!f2)
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return -1;
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av_fifo_generic_read(f, f2->buffer, len, NULL);
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f2->wptr += len;
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f2->wndx += len;
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av_free(f->buffer);
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*f= *f2;
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av_free(f2);
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}
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return 0;
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}
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// src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
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int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
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{
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int total = size;
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do {
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int len = FFMIN(f->end - f->wptr, size);
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if(func) {
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if(func(src, f->wptr, len) <= 0)
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break;
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} else {
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memcpy(f->wptr, src, len);
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src = (uint8_t*)src + len;
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}
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// Write memory barrier needed for SMP here in theory
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f->wptr += len;
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if (f->wptr >= f->end)
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f->wptr = f->buffer;
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f->wndx += len;
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size -= len;
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} while (size > 0);
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return total - size;
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}
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int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
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{
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// Read memory barrier needed for SMP here in theory
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do {
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int len = FFMIN(f->end - f->rptr, buf_size);
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if(func) func(dest, f->rptr, len);
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else{
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memcpy(dest, f->rptr, len);
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dest = (uint8_t*)dest + len;
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}
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// memory barrier needed for SMP here in theory
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av_fifo_drain(f, len);
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buf_size -= len;
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} while (buf_size > 0);
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return 0;
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}
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/** Discard data from the FIFO. */
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void av_fifo_drain(AVFifoBuffer *f, int size)
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{
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f->rptr += size;
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if (f->rptr >= f->end)
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f->rptr -= f->end - f->buffer;
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f->rndx += size;
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}
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