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https://github.com/FFmpeg/FFmpeg.git
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0871ae1a93
This is more efficient as in practice the check is redundant most of the time. Callers which do not know if enough data is available have to check it with av_fifo_size(). Doing the check in *read() means the caller has no choice to skip the check when its known to be redundant. Also the return value was never documented in a public header so changing it should not break the API. Besides this fixes the case where read() failed on a 100% full fifo. Originally committed as revision 13404 to svn://svn.ffmpeg.org/ffmpeg/trunk
119 lines
3.0 KiB
C
119 lines
3.0 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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int av_fifo_init(AVFifoBuffer *f, int size)
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{
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f->wptr = f->rptr =
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f->buffer = av_malloc(size);
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f->end = f->buffer + size;
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if (!f->buffer)
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return -1;
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return 0;
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}
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void av_fifo_free(AVFifoBuffer *f)
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{
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av_free(f->buffer);
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}
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int av_fifo_size(AVFifoBuffer *f)
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{
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int size = f->wptr - f->rptr;
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if (size < 0)
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size += f->end - f->buffer;
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return size;
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}
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int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size)
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{
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return av_fifo_generic_read(f, buf_size, NULL, buf);
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}
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/**
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* Resizes a FIFO.
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*/
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void av_fifo_realloc(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;
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av_fifo_init(&f2, new_size);
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av_fifo_read(f, f2.buffer, len);
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f2.wptr += len;
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av_free(f->buffer);
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*f= f2;
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}
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}
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void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size)
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{
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av_fifo_generic_write(f, (void *)buf, size, NULL);
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}
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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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f->wptr += len;
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if (f->wptr >= f->end)
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f->wptr = f->buffer;
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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, int buf_size, void (*func)(void*, void*, int), void* dest)
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{
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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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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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}
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