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- /*
- * a very simple circular buffer FIFO implementation
- * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
- * Copyright (c) 2006 Roman Shaposhnik
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * FFmpeg is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
- #include "common.h"
- #include "fifo.h"
- AVFifoBuffer *av_fifo_alloc(unsigned int size)
- {
- AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
- if (!f)
- return NULL;
- f->buffer = av_malloc(size);
- f->end = f->buffer + size;
- av_fifo_reset(f);
- if (!f->buffer)
- av_freep(&f);
- return f;
- }
- void av_fifo_free(AVFifoBuffer *f)
- {
- if (f) {
- av_freep(&f->buffer);
- av_free(f);
- }
- }
- void av_fifo_reset(AVFifoBuffer *f)
- {
- f->wptr = f->rptr = f->buffer;
- f->wndx = f->rndx = 0;
- }
- int av_fifo_size(AVFifoBuffer *f)
- {
- return (uint32_t)(f->wndx - f->rndx);
- }
- int av_fifo_space(AVFifoBuffer *f)
- {
- return f->end - f->buffer - av_fifo_size(f);
- }
- int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size)
- {
- unsigned int old_size = f->end - f->buffer;
- if (old_size < new_size) {
- int len = av_fifo_size(f);
- AVFifoBuffer *f2 = av_fifo_alloc(new_size);
- if (!f2)
- return AVERROR(ENOMEM);
- av_fifo_generic_read(f, f2->buffer, len, NULL);
- f2->wptr += len;
- f2->wndx += len;
- av_free(f->buffer);
- *f = *f2;
- av_free(f2);
- }
- return 0;
- }
- int av_fifo_grow(AVFifoBuffer *f, unsigned int size)
- {
- unsigned int old_size = f->end - f->buffer;
- if(size + (unsigned)av_fifo_size(f) < size)
- return AVERROR(EINVAL);
- size += av_fifo_size(f);
- if (old_size < size)
- return av_fifo_realloc2(f, FFMAX(size, 2*size));
- return 0;
- }
- // src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
- int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
- {
- int total = size;
- uint32_t wndx= f->wndx;
- uint8_t *wptr= f->wptr;
- do {
- int len = FFMIN(f->end - wptr, size);
- if (func) {
- if (func(src, wptr, len) <= 0)
- break;
- } else {
- memcpy(wptr, src, len);
- src = (uint8_t*)src + len;
- }
- // Write memory barrier needed for SMP here in theory
- wptr += len;
- if (wptr >= f->end)
- wptr = f->buffer;
- wndx += len;
- size -= len;
- } while (size > 0);
- f->wndx= wndx;
- f->wptr= wptr;
- return total - size;
- }
- int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
- {
- // Read memory barrier needed for SMP here in theory
- do {
- int len = FFMIN(f->end - f->rptr, buf_size);
- if(func) func(dest, f->rptr, len);
- else{
- memcpy(dest, f->rptr, len);
- dest = (uint8_t*)dest + len;
- }
- // memory barrier needed for SMP here in theory
- av_fifo_drain(f, len);
- buf_size -= len;
- } while (buf_size > 0);
- return 0;
- }
- /** Discard data from the FIFO. */
- void av_fifo_drain(AVFifoBuffer *f, int size)
- {
- f->rptr += size;
- if (f->rptr >= f->end)
- f->rptr -= f->end - f->buffer;
- f->rndx += size;
- }
- #ifdef TEST
- #undef printf
- int main(void)
- {
- /* create a FIFO buffer */
- AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int));
- int i, j, n;
- /* fill data */
- for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++)
- av_fifo_generic_write(fifo, &i, sizeof(int), NULL);
- /* peek at FIFO */
- n = av_fifo_size(fifo)/sizeof(int);
- for (i = -n+1; i < n; i++) {
- int *v = (int *)av_fifo_peek2(fifo, i*sizeof(int));
- printf("%d: %d\n", i, *v);
- }
- printf("\n");
- /* read data */
- for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) {
- av_fifo_generic_read(fifo, &j, sizeof(int), NULL);
- printf("%d ", j);
- }
- printf("\n");
- av_fifo_free(fifo);
- return 0;
- }
- #endif
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