mirror of
https://github.com/mpv-player/mpv
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591e21a2eb
The standard header is stdatomic.h, so the extra "s" freaks me out every time I look at it.
133 lines
4.9 KiB
C
133 lines
4.9 KiB
C
/*
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* This file is part of mpv.
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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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#ifndef MP_ATOMIC_H
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#define MP_ATOMIC_H
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#include <inttypes.h>
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#include "config.h"
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#if HAVE_STDATOMIC
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#include <stdatomic.h>
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#else
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// Emulate the parts of C11 stdatomic.h needed by mpv.
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// Still relies on gcc/clang atomic builtins.
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typedef struct { volatile unsigned long v; } atomic_ulong;
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typedef struct { volatile int v; } atomic_int;
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typedef struct { volatile unsigned int v; } atomic_uint;
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typedef struct { volatile _Bool v; } atomic_bool;
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typedef struct { volatile long long v; } atomic_llong;
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typedef struct { volatile uint_least32_t v; } atomic_uint_least32_t;
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typedef struct { volatile unsigned long long v; } atomic_ullong;
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#define ATOMIC_VAR_INIT(x) \
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{.v = (x)}
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#define memory_order_relaxed 1
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#define memory_order_seq_cst 2
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#define atomic_load_explicit(p, e) atomic_load(p)
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#if HAVE_ATOMIC_BUILTINS
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#define atomic_load(p) \
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__atomic_load_n(&(p)->v, __ATOMIC_SEQ_CST)
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#define atomic_store(p, val) \
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__atomic_store_n(&(p)->v, val, __ATOMIC_SEQ_CST)
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#define atomic_fetch_add(a, b) \
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__atomic_fetch_add(&(a)->v, b, __ATOMIC_SEQ_CST)
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#define atomic_fetch_and(a, b) \
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__atomic_fetch_and(&(a)->v, b, __ATOMIC_SEQ_CST)
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#define atomic_fetch_or(a, b) \
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__atomic_fetch_or(&(a)->v, b, __ATOMIC_SEQ_CST)
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#define atomic_compare_exchange_strong(a, b, c) \
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__atomic_compare_exchange_n(&(a)->v, b, c, 0, __ATOMIC_SEQ_CST, \
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__ATOMIC_SEQ_CST)
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#elif HAVE_SYNC_BUILTINS
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#define atomic_load(p) \
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__sync_fetch_and_add(&(p)->v, 0)
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#define atomic_store(p, val) \
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(__sync_synchronize(), (p)->v = (val), __sync_synchronize())
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#define atomic_fetch_add(a, b) \
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__sync_fetch_and_add(&(a)->v, b)
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#define atomic_fetch_and(a, b) \
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__sync_fetch_and_and(&(a)->v, b)
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#define atomic_fetch_or(a, b) \
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__sync_fetch_and_or(&(a)->v, b)
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// Assumes __sync_val_compare_and_swap is "strong" (using the C11 meaning).
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#define atomic_compare_exchange_strong(p, old, new) \
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({ __typeof__((p)->v) val_ = __sync_val_compare_and_swap(&(p)->v, *(old), new); \
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bool ok_ = val_ == *(old); \
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if (!ok_) *(old) = val_; \
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ok_; })
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#elif defined(__GNUC__)
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#include <pthread.h>
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extern pthread_mutex_t mp_atomic_mutex;
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#define atomic_load(p) \
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({ __typeof__(p) p_ = (p); \
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pthread_mutex_lock(&mp_atomic_mutex); \
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__typeof__(p_->v) v = p_->v; \
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pthread_mutex_unlock(&mp_atomic_mutex); \
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v; })
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#define atomic_store(p, val) \
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({ __typeof__(val) val_ = (val); \
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__typeof__(p) p_ = (p); \
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pthread_mutex_lock(&mp_atomic_mutex); \
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p_->v = val_; \
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pthread_mutex_unlock(&mp_atomic_mutex); })
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#define atomic_fetch_op(a, b, op) \
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({ __typeof__(a) a_ = (a); \
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__typeof__(b) b_ = (b); \
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pthread_mutex_lock(&mp_atomic_mutex); \
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__typeof__(a_->v) v = a_->v; \
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a_->v = v op b_; \
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pthread_mutex_unlock(&mp_atomic_mutex); \
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v; })
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#define atomic_fetch_add(a, b) atomic_fetch_op(a, b, +)
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#define atomic_fetch_and(a, b) atomic_fetch_op(a, b, &)
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#define atomic_fetch_or(a, b) atomic_fetch_op(a, b, |)
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#define atomic_compare_exchange_strong(p, old, new) \
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({ __typeof__(p) p_ = (p); \
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__typeof__(old) old_ = (old); \
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__typeof__(new) new_ = (new); \
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pthread_mutex_lock(&mp_atomic_mutex); \
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int res = p_->v == *old_; \
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if (res) { \
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p_->v = new_; \
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} else { \
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*old_ = p_->v; \
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} \
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pthread_mutex_unlock(&mp_atomic_mutex); \
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res; })
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#else
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# error "this should have been a configuration error, report a bug please"
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#endif /* no atomics */
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#endif /* else HAVE_STDATOMIC */
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#endif
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