mirror of
https://github.com/FFmpeg/FFmpeg.git
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7336e39f3c
Allows to alloc fifo buffer by passing number of elements and size of element. Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
212 lines
5.2 KiB
C
212 lines
5.2 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 "avassert.h"
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#include "common.h"
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#include "fifo.h"
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static AVFifoBuffer *fifo_alloc_common(void *buffer, size_t size)
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{
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AVFifoBuffer *f;
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if (!buffer)
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return NULL;
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f = av_mallocz(sizeof(AVFifoBuffer));
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if (!f) {
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av_free(buffer);
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return NULL;
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}
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f->buffer = buffer;
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f->end = f->buffer + size;
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av_fifo_reset(f);
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return f;
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}
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AVFifoBuffer *av_fifo_alloc(unsigned int size)
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{
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void *buffer = av_malloc(size);
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return fifo_alloc_common(buffer, size);
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}
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AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size)
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{
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void *buffer = av_malloc_array(nmemb, size);
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return fifo_alloc_common(buffer, nmemb * size);
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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_freep(&f->buffer);
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av_free(f);
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}
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}
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void av_fifo_freep(AVFifoBuffer **f)
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{
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if (f) {
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av_fifo_free(*f);
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*f = NULL;
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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(FF_CONST_AVUTIL53 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(FF_CONST_AVUTIL53 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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{
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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 AVERROR(ENOMEM);
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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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int av_fifo_grow(AVFifoBuffer *f, unsigned int size)
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{
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unsigned int old_size = f->end - f->buffer;
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if(size + (unsigned)av_fifo_size(f) < size)
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return AVERROR(EINVAL);
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size += av_fifo_size(f);
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if (old_size < size)
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return av_fifo_realloc2(f, FFMAX(size, 2*size));
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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
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* updating (like a pointer or byte counter) */
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int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size,
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int (*func)(void *, void *, int))
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{
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int total = size;
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uint32_t wndx= f->wndx;
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uint8_t *wptr= f->wptr;
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do {
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int len = FFMIN(f->end - wptr, size);
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if (func) {
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if (func(src, wptr, len) <= 0)
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break;
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} else {
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memcpy(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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wptr += len;
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if (wptr >= f->end)
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wptr = f->buffer;
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wndx += len;
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size -= len;
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} while (size > 0);
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f->wndx= wndx;
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f->wptr= wptr;
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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,
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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)
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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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av_assert2(av_fifo_size(f) >= size);
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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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#ifdef TEST
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int main(void)
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{
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/* create a FIFO buffer */
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AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int));
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int i, j, n;
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/* fill data */
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for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++)
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av_fifo_generic_write(fifo, &i, sizeof(int), NULL);
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/* peek at FIFO */
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n = av_fifo_size(fifo) / sizeof(int);
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for (i = -n + 1; i < n; i++) {
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int *v = (int *)av_fifo_peek2(fifo, i * sizeof(int));
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printf("%d: %d\n", i, *v);
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}
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printf("\n");
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/* read data */
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for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) {
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av_fifo_generic_read(fifo, &j, sizeof(int), NULL);
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printf("%d ", j);
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}
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printf("\n");
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av_fifo_free(fifo);
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return 0;
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}
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#endif
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