/*
- * A very simple circular buffer FIFO implementation
+ * 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.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav 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,
+ * Libav 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
+ * License along with Libav; 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"
-int av_fifo_init(AVFifoBuffer *f, unsigned int size)
+AVFifoBuffer *av_fifo_alloc(unsigned int size)
{
- size= FFMAX(size, size+1);
- f->wptr = f->rptr =
+ AVFifoBuffer *f = av_mallocz(sizeof(AVFifoBuffer));
+ if (!f)
+ return NULL;
f->buffer = av_malloc(size);
- f->end = f->buffer + size;
+ f->end = f->buffer + size;
+ av_fifo_reset(f);
if (!f->buffer)
- return -1;
- return 0;
+ av_freep(&f);
+ return f;
}
void av_fifo_free(AVFifoBuffer *f)
{
- av_free(f->buffer);
+ if (f) {
+ av_free(f->buffer);
+ av_free(f);
+ }
}
-int av_fifo_size(AVFifoBuffer *f)
+void av_fifo_reset(AVFifoBuffer *f)
{
- int size = f->wptr - f->rptr;
- if (size < 0)
- size += f->end - f->buffer;
- return size;
+ f->wptr = f->rptr = f->buffer;
+ f->wndx = f->rndx = 0;
}
-int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size)
+int av_fifo_size(AVFifoBuffer *f)
{
- return av_fifo_generic_read(f, buf_size, NULL, buf);
+ return (uint32_t)(f->wndx - f->rndx);
}
-#if LIBAVUTIL_VERSION_MAJOR < 50
-/**
- * Resizes a FIFO.
- */
-void av_fifo_realloc(AVFifoBuffer *f, unsigned int new_size) {
- av_fifo_realloc2(f, new_size);
+int av_fifo_space(AVFifoBuffer *f)
+{
+ return f->end - f->buffer - av_fifo_size(f);
}
-#endif
-int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {
- unsigned int old_size= f->end - f->buffer;
+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;
+ if (old_size < new_size) {
+ int len = av_fifo_size(f);
+ AVFifoBuffer *f2 = av_fifo_alloc(new_size);
- if (av_fifo_init(&f2, new_size) < 0)
+ if (!f2)
return -1;
- av_fifo_read(f, f2.buffer, len);
- f2.wptr += len;
+ av_fifo_generic_read(f, f2->buffer, len, NULL);
+ f2->wptr += len;
+ f2->wndx += len;
av_free(f->buffer);
- *f= f2;
+ *f = *f2;
+ av_free(f2);
}
return 0;
}
-void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size)
-{
- av_fifo_generic_write(f, (void *)buf, size, NULL);
-}
-
-int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
+/* 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;
do {
int len = FFMIN(f->end - f->wptr, size);
- if(func) {
- if(func(src, f->wptr, len) <= 0)
+ if (func) {
+ if (func(src, f->wptr, len) <= 0)
break;
} else {
memcpy(f->wptr, src, len);
- src = (uint8_t*)src + len;
+ src = (uint8_t *)src + len;
}
+// Write memory barrier needed for SMP here in theory
f->wptr += len;
if (f->wptr >= f->end)
f->wptr = f->buffer;
- size -= len;
+ f->wndx += len;
+ size -= len;
} while (size > 0);
return total - size;
}
-
-int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest)
+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{
+ if (func)
+ func(dest, f->rptr, len);
+ else {
memcpy(dest, f->rptr, len);
- dest = (uint8_t*)dest + 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 */
+/** 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
+
+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
projects / ffmpeg / blobdiff