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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 <stdint.h>
#include <string.h>
#include "avassert.h"
#include "error.h"
#include "fifo.h"
#include "macros.h"
#include "mem.h"
// by default the FIFO can be auto-grown to 1MB
#define AUTO_GROW_DEFAULT_BYTES (1024 * 1024)
struct AVFifo {
uint8_t *buffer;
size_t elem_size, nb_elems;
size_t offset_r, offset_w;
// distinguishes the ambiguous situation offset_r == offset_w
int is_empty;
unsigned int flags;
size_t auto_grow_limit;
};
AVFifo *av_fifo_alloc2(size_t nb_elems, size_t elem_size,
unsigned int flags)
{
AVFifo *f;
void *buffer = NULL;
if (!elem_size)
return NULL;
if (nb_elems) {
buffer = av_realloc_array(NULL, nb_elems, elem_size);
if (!buffer)
return NULL;
}
f = av_mallocz(sizeof(*f));
if (!f) {
av_free(buffer);
return NULL;
}
f->buffer = buffer;
f->nb_elems = nb_elems;
f->elem_size = elem_size;
f->is_empty = 1;
f->flags = flags;
f->auto_grow_limit = FFMAX(AUTO_GROW_DEFAULT_BYTES / elem_size, 1);
return f;
}
void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems)
{
f->auto_grow_limit = max_elems;
}
size_t av_fifo_elem_size(const AVFifo *f)
{
return f->elem_size;
}
size_t av_fifo_can_read(const AVFifo *f)
{
if (f->offset_w <= f->offset_r && !f->is_empty)
return f->nb_elems - f->offset_r + f->offset_w;
return f->offset_w - f->offset_r;
}
size_t av_fifo_can_write(const AVFifo *f)
{
return f->nb_elems - av_fifo_can_read(f);
}
int av_fifo_grow2(AVFifo *f, size_t inc)
{
uint8_t *tmp;
if (inc > SIZE_MAX - f->nb_elems)
return AVERROR(EINVAL);
tmp = av_realloc_array(f->buffer, f->nb_elems + inc, f->elem_size);
if (!tmp)
return AVERROR(ENOMEM);
f->buffer = tmp;
// move the data from the beginning of the ring buffer
// to the newly allocated space
if (f->offset_w <= f->offset_r && !f->is_empty) {
const size_t copy = FFMIN(inc, f->offset_w);
memcpy(tmp + f->nb_elems * f->elem_size, tmp, copy * f->elem_size);
if (copy < f->offset_w) {
memmove(tmp, tmp + copy * f->elem_size,
(f->offset_w - copy) * f->elem_size);
f->offset_w -= copy;
} else
f->offset_w = copy == inc ? 0 : f->nb_elems + copy;
}
f->nb_elems += inc;
return 0;
}
static int fifo_check_space(AVFifo *f, size_t to_write)
{
const size_t can_write = av_fifo_can_write(f);
const size_t need_grow = to_write > can_write ? to_write - can_write : 0;
size_t can_grow;
if (!need_grow)
return 0;
can_grow = f->auto_grow_limit > f->nb_elems ?
f->auto_grow_limit - f->nb_elems : 0;
if ((f->flags & AV_FIFO_FLAG_AUTO_GROW) && need_grow <= can_grow) {
// allocate a bit more than necessary, if we can
const size_t inc = (need_grow < can_grow / 2 ) ? need_grow * 2 : can_grow;
return av_fifo_grow2(f, inc);
}
return AVERROR(ENOSPC);
}
static int fifo_write_common(AVFifo *f, const uint8_t *buf, size_t *nb_elems,
AVFifoCB read_cb, void *opaque)
{
size_t to_write = *nb_elems;
size_t offset_w;
int ret = 0;
ret = fifo_check_space(f, to_write);
if (ret < 0)
return ret;
offset_w = f->offset_w;
while (to_write > 0) {
size_t len = FFMIN(f->nb_elems - offset_w, to_write);
uint8_t *wptr = f->buffer + offset_w * f->elem_size;
if (read_cb) {
ret = read_cb(opaque, wptr, &len);
if (ret < 0 || len == 0)
break;
} else {
memcpy(wptr, buf, len * f->elem_size);
buf += len * f->elem_size;
}
offset_w += len;
if (offset_w >= f->nb_elems)
offset_w = 0;
to_write -= len;
}
f->offset_w = offset_w;
if (*nb_elems != to_write)
f->is_empty = 0;
*nb_elems -= to_write;
return ret;
}
int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems)
{
return fifo_write_common(f, buf, &nb_elems, NULL, NULL);
}
int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb,
void *opaque, size_t *nb_elems)
{
return fifo_write_common(f, NULL, nb_elems, read_cb, opaque);
}
static int fifo_peek_common(const AVFifo *f, uint8_t *buf, size_t *nb_elems,
size_t offset, AVFifoCB write_cb, void *opaque)
{
size_t to_read = *nb_elems;
size_t offset_r = f->offset_r;
size_t can_read = av_fifo_can_read(f);
int ret = 0;
if (offset > can_read || to_read > can_read - offset) {
*nb_elems = 0;
return AVERROR(EINVAL);
}
if (offset_r >= f->nb_elems - offset)
offset_r -= f->nb_elems - offset;
else
offset_r += offset;
while (to_read > 0) {
size_t len = FFMIN(f->nb_elems - offset_r, to_read);
uint8_t *rptr = f->buffer + offset_r * f->elem_size;
if (write_cb) {
ret = write_cb(opaque, rptr, &len);
if (ret < 0 || len == 0)
break;
} else {
memcpy(buf, rptr, len * f->elem_size);
buf += len * f->elem_size;
}
offset_r += len;
if (offset_r >= f->nb_elems)
offset_r = 0;
to_read -= len;
}
*nb_elems -= to_read;
return ret;
}
int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems)
{
int ret = fifo_peek_common(f, buf, &nb_elems, 0, NULL, NULL);
av_fifo_drain2(f, nb_elems);
return ret;
}
int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb,
void *opaque, size_t *nb_elems)
{
int ret = fifo_peek_common(f, NULL, nb_elems, 0, write_cb, opaque);
av_fifo_drain2(f, *nb_elems);
return ret;
}
int av_fifo_peek(const AVFifo *f, void *buf, size_t nb_elems, size_t offset)
{
return fifo_peek_common(f, buf, &nb_elems, offset, NULL, NULL);
}
int av_fifo_peek_to_cb(const AVFifo *f, AVFifoCB write_cb, void *opaque,
size_t *nb_elems, size_t offset)
{
return fifo_peek_common(f, NULL, nb_elems, offset, write_cb, opaque);
}
void av_fifo_drain2(AVFifo *f, size_t size)
{
const size_t cur_size = av_fifo_can_read(f);
av_assert0(cur_size >= size);
if (cur_size == size)
f->is_empty = 1;
if (f->offset_r >= f->nb_elems - size)
f->offset_r -= f->nb_elems - size;
else
f->offset_r += size;
}
void av_fifo_reset2(AVFifo *f)
{
f->offset_r = f->offset_w = 0;
f->is_empty = 1;
}
void av_fifo_freep2(AVFifo **f)
{
if (*f) {
av_freep(&(*f)->buffer);
av_freep(f);
}
}
#if FF_API_FIFO_OLD_API
#include "internal.h"
FF_DISABLE_DEPRECATION_WARNINGS
#define OLD_FIFO_SIZE_MAX (size_t)FFMIN3(INT_MAX, UINT32_MAX, SIZE_MAX)
AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size)
{
AVFifoBuffer *f;
void *buffer;
if (nmemb > OLD_FIFO_SIZE_MAX / size)
return NULL;
buffer = av_realloc_array(NULL, nmemb, size);
if (!buffer)
return NULL;
f = av_mallocz(sizeof(AVFifoBuffer));
if (!f) {
av_free(buffer);
return NULL;
}
f->buffer = buffer;
f->end = f->buffer + nmemb * size;
av_fifo_reset(f);
return f;
}
AVFifoBuffer *av_fifo_alloc(unsigned int size)
{
return av_fifo_alloc_array(size, 1);
}
void av_fifo_free(AVFifoBuffer *f)
{
if (f) {
av_freep(&f->buffer);
av_free(f);
}
}
void av_fifo_freep(AVFifoBuffer **f)
{
if (f) {
av_fifo_free(*f);
*f = NULL;
}
}
void av_fifo_reset(AVFifoBuffer *f)
{
f->wptr = f->rptr = f->buffer;
f->wndx = f->rndx = 0;
}
int av_fifo_size(const AVFifoBuffer *f)
{
return (uint32_t)(f->wndx - f->rndx);
}
int av_fifo_space(const 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 (new_size > OLD_FIFO_SIZE_MAX)
return AVERROR(EINVAL);
if (old_size < new_size) {
size_t offset_r = f->rptr - f->buffer;
size_t offset_w = f->wptr - f->buffer;
uint8_t *tmp;
tmp = av_realloc(f->buffer, new_size);
if (!tmp)
return AVERROR(ENOMEM);
// move the data from the beginning of the ring buffer
// to the newly allocated space
// the second condition distinguishes full vs empty fifo
if (offset_w <= offset_r && av_fifo_size(f)) {
const size_t copy = FFMIN(new_size - old_size, offset_w);
memcpy(tmp + old_size, tmp, copy);
if (copy < offset_w) {
memmove(tmp, tmp + copy , offset_w - copy);
offset_w -= copy;
} else
offset_w = old_size + copy;
}
f->buffer = tmp;
f->end = f->buffer + new_size;
f->rptr = f->buffer + offset_r;
f->wptr = f->buffer + offset_w;
}
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*old_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;
if (size > av_fifo_space(f))
return AVERROR(ENOSPC);
do {
int len = FFMIN(f->end - wptr, size);
if (func) {
len = func(src, wptr, len);
if (len <= 0)
break;
} else {
memcpy(wptr, src, len);
src = (uint8_t *)src + len;
}
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_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int))
{
uint8_t *rptr = f->rptr;
if (offset < 0 || buf_size > av_fifo_size(f) - offset)
return AVERROR(EINVAL);
if (offset >= f->end - rptr)
rptr += offset - (f->end - f->buffer);
else
rptr += offset;
while (buf_size > 0) {
int len;
if (rptr >= f->end)
rptr -= f->end - f->buffer;
len = FFMIN(f->end - rptr, buf_size);
if (func)
func(dest, rptr, len);
else {
memcpy(dest, rptr, len);
dest = (uint8_t *)dest + len;
}
buf_size -= len;
rptr += len;
}
return 0;
}
int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size,
void (*func)(void *, void *, int))
{
return av_fifo_generic_peek_at(f, dest, 0, buf_size, func);
}
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size,
void (*func)(void *, void *, int))
{
if (buf_size > av_fifo_size(f))
return AVERROR(EINVAL);
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;
}
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)
{
av_assert2(av_fifo_size(f) >= size);
f->rptr += size;
if (f->rptr >= f->end)
f->rptr -= f->end - f->buffer;
f->rndx += size;
}
FF_ENABLE_DEPRECATION_WARNINGS
#endif