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/*
* This file is part of mpv.
* 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/>.
*/
#ifndef MP_ATOMICS_H
#define MP_ATOMICS_H
#include <inttypes.h>
#include "config.h"
#if HAVE_STDATOMIC
#include <stdatomic.h>
#else
// Emulate the parts of C11 stdatomic.h needed by mpv.
// Still relies on gcc/clang atomic builtins.
typedef struct { volatile unsigned long v; } atomic_ulong;
typedef struct { volatile int v; } atomic_int;
typedef struct { volatile unsigned int v; } atomic_uint;
typedef struct { volatile _Bool v; } atomic_bool;
typedef struct { volatile long long v; } atomic_llong;
typedef struct { volatile uint_least32_t v; } atomic_uint_least32_t;
typedef struct { volatile unsigned long long v; } atomic_ullong;
#define ATOMIC_VAR_INIT(x) \
{.v = (x)}
#define memory_order_relaxed 1
#define memory_order_seq_cst 2
#define atomic_load_explicit(p, e) atomic_load(p)
#if HAVE_ATOMIC_BUILTINS
#define atomic_load(p) \
__atomic_load_n(&(p)->v, __ATOMIC_SEQ_CST)
#define atomic_store(p, val) \
__atomic_store_n(&(p)->v, val, __ATOMIC_SEQ_CST)
#define atomic_fetch_add(a, b) \
__atomic_fetch_add(&(a)->v, b, __ATOMIC_SEQ_CST)
#define atomic_fetch_and(a, b) \
__atomic_fetch_and(&(a)->v, b, __ATOMIC_SEQ_CST)
#define atomic_fetch_or(a, b) \
__atomic_fetch_or(&(a)->v, b, __ATOMIC_SEQ_CST)
#define atomic_compare_exchange_strong(a, b, c) \
__atomic_compare_exchange_n(&(a)->v, b, c, 0, __ATOMIC_SEQ_CST, \
__ATOMIC_SEQ_CST)
#elif HAVE_SYNC_BUILTINS
#define atomic_load(p) \
__sync_fetch_and_add(&(p)->v, 0)
#define atomic_store(p, val) \
(__sync_synchronize(), (p)->v = (val), __sync_synchronize())
#define atomic_fetch_add(a, b) \
__sync_fetch_and_add(&(a)->v, b)
#define atomic_fetch_and(a, b) \
__sync_fetch_and_and(&(a)->v, b)
#define atomic_fetch_or(a, b) \
__sync_fetch_and_or(&(a)->v, b)
// Assumes __sync_val_compare_and_swap is "strong" (using the C11 meaning).
#define atomic_compare_exchange_strong(p, old, new) \
({ __typeof__((p)->v) val_ = __sync_val_compare_and_swap(&(p)->v, *(old), new); \
bool ok_ = val_ == *(old); \
if (!ok_) *(old) = val_; \
ok_; })
#elif defined(__GNUC__)
#include <pthread.h>
extern pthread_mutex_t mp_atomic_mutex;
#define atomic_load(p) \
({ __typeof__(p) p_ = (p); \
pthread_mutex_lock(&mp_atomic_mutex); \
__typeof__(p_->v) v = p_->v; \
pthread_mutex_unlock(&mp_atomic_mutex); \
v; })
#define atomic_store(p, val) \
({ __typeof__(val) val_ = (val); \
__typeof__(p) p_ = (p); \
pthread_mutex_lock(&mp_atomic_mutex); \
p_->v = val_; \
pthread_mutex_unlock(&mp_atomic_mutex); })
#define atomic_fetch_op(a, b, op) \
({ __typeof__(a) a_ = (a); \
__typeof__(b) b_ = (b); \
pthread_mutex_lock(&mp_atomic_mutex); \
__typeof__(a_->v) v = a_->v; \
a_->v = v op b_; \
pthread_mutex_unlock(&mp_atomic_mutex); \
v; })
#define atomic_fetch_add(a, b) atomic_fetch_op(a, b, +)
#define atomic_fetch_and(a, b) atomic_fetch_op(a, b, &)
#define atomic_fetch_or(a, b) atomic_fetch_op(a, b, |)
#define atomic_compare_exchange_strong(p, old, new) \
({ __typeof__(p) p_ = (p); \
__typeof__(old) old_ = (old); \
__typeof__(new) new_ = (new); \
pthread_mutex_lock(&mp_atomic_mutex); \
int res = p_->v == *old_; \
if (res) { \
p_->v = new_; \
} else { \
*old_ = p_->v; \
} \
pthread_mutex_unlock(&mp_atomic_mutex); \
res; })
#else
# error "this should have been a configuration error, report a bug please"
#endif /* no atomics */
#endif /* else HAVE_STDATOMIC */
#endif
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