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ffmpeg / libavutil / fifo.c @ f5a478f6

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/*
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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 library 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 of the License, or (at your option) any later version.
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 *
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 * This library 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 this library; 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->buffer = av_malloc(size);
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    if (!f->buffer)
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        return -1;
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    f->end = f->buffer + size;
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    f->wptr = f->rptr = f->buffer;
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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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/**
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 * Get data from the fifo (returns -1 if not enough data).
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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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    int len;
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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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    if (size < buf_size)
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        return -1;
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    while (buf_size > 0) {
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        len = FFMIN(f->end - f->rptr, buf_size);
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        memcpy(buf, f->rptr, len);
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        buf += len;
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        f->rptr += len;
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        if (f->rptr >= f->end)
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            f->rptr = f->buffer;
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        buf_size -= len;
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    }
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    return 0;
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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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        uint8_t *old= f->buffer;
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        f->buffer= av_realloc(f->buffer, new_size);
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        f->rptr += f->buffer - old;
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        f->wptr += f->buffer - old;
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        if(f->wptr < f->rptr){
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            memmove(f->rptr + new_size - old_size, f->rptr, f->buffer + old_size - f->rptr);
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            f->rptr += new_size - old_size;
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        }
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        f->end= f->buffer + new_size;
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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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    int len;
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    while (size > 0) {
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        len = FFMIN(f->end - f->wptr, size);
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        memcpy(f->wptr, buf, len);
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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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        buf += len;
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        size -= len;
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    }
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}
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/* get data from the fifo (return -1 if not enough data) */
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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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    int len;
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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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    if (size < buf_size)
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        return -1;
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    while (buf_size > 0) {
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        len = FFMIN(f->end - f->rptr, buf_size);
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        func(dest, f->rptr, len);
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        f->rptr += len;
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        if (f->rptr >= f->end)
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            f->rptr = f->buffer;
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        buf_size -= len;
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    }
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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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}