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