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authorwm4 <wm4@nowhere>2016-09-07 11:26:25 +0200
committerwm4 <wm4@nowhere>2016-09-07 11:26:25 +0200
commit591e21a2ebd105c33127d4a792d4d0e1a083fcfc (patch)
tree14765300678fa16bff6ca0f47ec6cfbbb866d871 /osdep/atomic.h
parentc6b7a4dacee3067ad00abdb3abf71c7e8eb62e78 (diff)
downloadmpv-591e21a2ebd105c33127d4a792d4d0e1a083fcfc.tar.bz2
mpv-591e21a2ebd105c33127d4a792d4d0e1a083fcfc.tar.xz
osdep: rename atomics.h to atomic.h
The standard header is stdatomic.h, so the extra "s" freaks me out every time I look at it.
Diffstat (limited to 'osdep/atomic.h')
-rw-r--r--osdep/atomic.h132
1 files changed, 132 insertions, 0 deletions
diff --git a/osdep/atomic.h b/osdep/atomic.h
new file mode 100644
index 0000000000..9028a504eb
--- /dev/null
+++ b/osdep/atomic.h
@@ -0,0 +1,132 @@
+/*
+ * 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_ATOMIC_H
+#define MP_ATOMIC_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