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/*
* Copyright © 2007 Chris Wilson
* Copyright © 2009,2010 Red Hat, Inc.
* Copyright © 2011,2012 Google, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Contributor(s):
* Chris Wilson <chris@chris-wilson.co.uk>
* Red Hat Author(s): Behdad Esfahbod
* Google Author(s): Behdad Esfahbod
*/
#ifndef HB_ATOMIC_HH
#define HB_ATOMIC_HH
#include "hb.hh"
#include "hb-meta.hh"
/*
* Atomic integers and pointers.
*/
/* We need external help for these */
#if defined(hb_atomic_int_impl_add) \
&& defined(hb_atomic_ptr_impl_get) \
&& defined(hb_atomic_ptr_impl_cmpexch)
/* Defined externally, i.e. in config.h. */
#elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE)
/* C++11-style GCC primitives. We prefer these as they don't require linking to libstdc++ / libc++. */
#define _hb_memory_barrier() __sync_synchronize ()
#define hb_atomic_int_impl_add(AI, V) __atomic_fetch_add ((AI), (V), __ATOMIC_ACQ_REL)
#define hb_atomic_int_impl_set_relaxed(AI, V) __atomic_store_n ((AI), (V), __ATOMIC_RELAXED)
#define hb_atomic_int_impl_set(AI, V) __atomic_store_n ((AI), (V), __ATOMIC_RELEASE)
#define hb_atomic_int_impl_get_relaxed(AI) __atomic_load_n ((AI), __ATOMIC_RELAXED)
#define hb_atomic_int_impl_get(AI) __atomic_load_n ((AI), __ATOMIC_ACQUIRE)
#define hb_atomic_ptr_impl_set_relaxed(P, V) __atomic_store_n ((P), (V), __ATOMIC_RELAXED)
#define hb_atomic_ptr_impl_get_relaxed(P) __atomic_load_n ((P), __ATOMIC_RELAXED)
#define hb_atomic_ptr_impl_get(P) __atomic_load_n ((P), __ATOMIC_ACQUIRE)
static inline bool
_hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N)
{
const void *O = O_; // Need lvalue
return __atomic_compare_exchange_n ((void **) P, (void **) &O, (void *) N, true, __ATOMIC_ACQ_REL, __ATOMIC_RELAXED);
}
#define hb_atomic_ptr_impl_cmpexch(P,O,N) _hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N))
#elif !defined(HB_NO_MT)
/* C++11 atomics. */
#include <atomic>
#define _hb_memory_barrier() std::atomic_thread_fence(std::memory_order_ack_rel)
#define _hb_memory_r_barrier() std::atomic_thread_fence(std::memory_order_acquire)
#define _hb_memory_w_barrier() std::atomic_thread_fence(std::memory_order_release)
#define hb_atomic_int_impl_add(AI, V) (reinterpret_cast<std::atomic<int> *> (AI)->fetch_add ((V), std::memory_order_acq_rel))
#define hb_atomic_int_impl_set_relaxed(AI, V) (reinterpret_cast<std::atomic<int> *> (AI)->store ((V), std::memory_order_relaxed))
#define hb_atomic_int_impl_set(AI, V) (reinterpret_cast<std::atomic<int> *> (AI)->store ((V), std::memory_order_release))
#define hb_atomic_int_impl_get_relaxed(AI) (reinterpret_cast<std::atomic<int> const *> (AI)->load (std::memory_order_relaxed))
#define hb_atomic_int_impl_get(AI) (reinterpret_cast<std::atomic<int> const *> (AI)->load (std::memory_order_acquire))
#define hb_atomic_ptr_impl_set_relaxed(P, V) (reinterpret_cast<std::atomic<void*> *> (P)->store ((V), std::memory_order_relaxed))
#define hb_atomic_ptr_impl_get_relaxed(P) (reinterpret_cast<std::atomic<void*> const *> (P)->load (std::memory_order_relaxed))
#define hb_atomic_ptr_impl_get(P) (reinterpret_cast<std::atomic<void*> *> (P)->load (std::memory_order_acquire))
static inline bool
_hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N)
{
const void *O = O_; // Need lvalue
return reinterpret_cast<std::atomic<const void*> *> (P)->compare_exchange_weak (O, N, std::memory_order_acq_rel, std::memory_order_relaxed);
}
#define hb_atomic_ptr_impl_cmpexch(P,O,N) _hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N))
#elif defined(HB_NO_MT)
#define hb_atomic_int_impl_add(AI, V) ((*(AI) += (V)) - (V))
#define _hb_memory_barrier() do {} while (0)
#define hb_atomic_ptr_impl_cmpexch(P,O,N) (* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false)
#else
#error "Could not find any system to define atomic_int macros."
#error "Check hb-atomic.hh for possible resolutions."
#endif
#ifndef _hb_memory_r_barrier
#define _hb_memory_r_barrier() _hb_memory_barrier ()
#endif
#ifndef _hb_memory_w_barrier
#define _hb_memory_w_barrier() _hb_memory_barrier ()
#endif
#ifndef hb_atomic_int_impl_set_relaxed
#define hb_atomic_int_impl_set_relaxed(AI, V) (*(AI) = (V))
#endif
#ifndef hb_atomic_int_impl_get_relaxed
#define hb_atomic_int_impl_get_relaxed(AI) (*(AI))
#endif
#ifndef hb_atomic_ptr_impl_set_relaxed
#define hb_atomic_ptr_impl_set_relaxed(P, V) (*(P) = (V))
#endif
#ifndef hb_atomic_ptr_impl_get_relaxed
#define hb_atomic_ptr_impl_get_relaxed(P) (*(P))
#endif
#ifndef hb_atomic_int_impl_set
inline void hb_atomic_int_impl_set (int *AI, int v) { _hb_memory_w_barrier (); *AI = v; }
#endif
#ifndef hb_atomic_int_impl_get
inline int hb_atomic_int_impl_get (const int *AI) { int v = *AI; _hb_memory_r_barrier (); return v; }
#endif
#ifndef hb_atomic_ptr_impl_get
inline void *hb_atomic_ptr_impl_get (void ** const P) { void *v = *P; _hb_memory_r_barrier (); return v; }
#endif
struct hb_atomic_int_t
{
hb_atomic_int_t () = default;
constexpr hb_atomic_int_t (int v) : v (v) {}
void set_relaxed (int v_) { hb_atomic_int_impl_set_relaxed (&v, v_); }
void set (int v_) { hb_atomic_int_impl_set (&v, v_); }
int get_relaxed () const { return hb_atomic_int_impl_get_relaxed (&v); }
int get () const { return hb_atomic_int_impl_get (&v); }
int inc () { return hb_atomic_int_impl_add (&v, 1); }
int dec () { return hb_atomic_int_impl_add (&v, -1); }
int v = 0;
};
template <typename P>
struct hb_atomic_ptr_t
{
typedef hb_remove_pointer<P> T;
hb_atomic_ptr_t () = default;
constexpr hb_atomic_ptr_t (T* v) : v (v) {}
void init (T* v_ = nullptr) { set_relaxed (v_); }
void set_relaxed (T* v_) { hb_atomic_ptr_impl_set_relaxed (&v, v_); }
T *get_relaxed () const { return (T *) hb_atomic_ptr_impl_get_relaxed (&v); }
T *get () const { return (T *) hb_atomic_ptr_impl_get ((void **) &v); }
bool cmpexch (const T *old, T *new_) const { return hb_atomic_ptr_impl_cmpexch ((void **) &v, (void *) old, (void *) new_); }
T * operator -> () const { return get (); }
template <typename C> operator C * () const { return get (); }
T *v = nullptr;
};
#endif /* HB_ATOMIC_HH */
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