mirror of https://github.com/mpv-player/mpv
131 lines
3.4 KiB
C
131 lines
3.4 KiB
C
/*
|
|
* This file is part of mpv.
|
|
* Copyright (c) 2012 wm4
|
|
* Copyright (c) 2013 Stefano Pigozzi <stefano.pigozzi@gmail.com>
|
|
*
|
|
* mpv 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.
|
|
*
|
|
* mpv 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 mpv. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <inttypes.h>
|
|
#include <libavutil/common.h>
|
|
#include <assert.h>
|
|
#include "mpv_talloc.h"
|
|
#include "osdep/atomic.h"
|
|
#include "ring.h"
|
|
|
|
struct mp_ring {
|
|
uint8_t *buffer;
|
|
|
|
/* Positions of the first readable/writeable chunks. Do not read this
|
|
* fields but use the atomic private accessors `mp_ring_get_wpos`
|
|
* and `mp_ring_get_rpos`. */
|
|
atomic_ullong rpos, wpos;
|
|
};
|
|
|
|
static unsigned long long mp_ring_get_wpos(struct mp_ring *buffer)
|
|
{
|
|
return atomic_load(&buffer->wpos);
|
|
}
|
|
|
|
static unsigned long long mp_ring_get_rpos(struct mp_ring *buffer)
|
|
{
|
|
return atomic_load(&buffer->rpos);
|
|
}
|
|
|
|
struct mp_ring *mp_ring_new(void *talloc_ctx, int size)
|
|
{
|
|
struct mp_ring *ringbuffer =
|
|
talloc_zero(talloc_ctx, struct mp_ring);
|
|
|
|
*ringbuffer = (struct mp_ring) {
|
|
.buffer = talloc_size(talloc_ctx, size),
|
|
};
|
|
|
|
return ringbuffer;
|
|
}
|
|
|
|
int mp_ring_read(struct mp_ring *buffer, unsigned char *dest, int len)
|
|
{
|
|
int size = mp_ring_size(buffer);
|
|
int buffered = mp_ring_buffered(buffer);
|
|
int read_len = FFMIN(len, buffered);
|
|
int read_ptr = mp_ring_get_rpos(buffer) % size;
|
|
|
|
int len1 = FFMIN(size - read_ptr, read_len);
|
|
int len2 = read_len - len1;
|
|
|
|
if (dest) {
|
|
memcpy(dest, buffer->buffer + read_ptr, len1);
|
|
memcpy(dest + len1, buffer->buffer, len2);
|
|
}
|
|
|
|
atomic_fetch_add(&buffer->rpos, read_len);
|
|
|
|
return read_len;
|
|
}
|
|
|
|
int mp_ring_drain(struct mp_ring *buffer, int len)
|
|
{
|
|
return mp_ring_read(buffer, NULL, len);
|
|
}
|
|
|
|
int mp_ring_write(struct mp_ring *buffer, unsigned char *src, int len)
|
|
{
|
|
int size = mp_ring_size(buffer);
|
|
int free = mp_ring_available(buffer);
|
|
int write_len = FFMIN(len, free);
|
|
int write_ptr = mp_ring_get_wpos(buffer) % size;
|
|
|
|
int len1 = FFMIN(size - write_ptr, write_len);
|
|
int len2 = write_len - len1;
|
|
|
|
memcpy(buffer->buffer + write_ptr, src, len1);
|
|
memcpy(buffer->buffer, src + len1, len2);
|
|
|
|
atomic_fetch_add(&buffer->wpos, write_len);
|
|
|
|
return write_len;
|
|
}
|
|
|
|
void mp_ring_reset(struct mp_ring *buffer)
|
|
{
|
|
atomic_store(&buffer->wpos, 0);
|
|
atomic_store(&buffer->rpos, 0);
|
|
}
|
|
|
|
int mp_ring_available(struct mp_ring *buffer)
|
|
{
|
|
return mp_ring_size(buffer) - mp_ring_buffered(buffer);
|
|
}
|
|
|
|
int mp_ring_size(struct mp_ring *buffer)
|
|
{
|
|
return talloc_get_size(buffer->buffer);
|
|
}
|
|
|
|
int mp_ring_buffered(struct mp_ring *buffer)
|
|
{
|
|
return (mp_ring_get_wpos(buffer) - mp_ring_get_rpos(buffer));
|
|
}
|
|
|
|
char *mp_ring_repr(struct mp_ring *buffer, void *talloc_ctx)
|
|
{
|
|
return talloc_asprintf(
|
|
talloc_ctx,
|
|
"Ringbuffer { .size = %dB, .buffered = %dB, .available = %dB }",
|
|
mp_ring_size(buffer),
|
|
mp_ring_buffered(buffer),
|
|
mp_ring_available(buffer));
|
|
}
|