/*
 * 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"


/*
 * 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. */

#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) && __cplusplus >= 201103L

/* 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> *> (AI)->load (std::memory_order_relaxed))
#define hb_atomic_int_impl_get(AI)              (reinterpret_cast<std::atomic<int> *> (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*> *> (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) && defined(_WIN32)

#include <windows.h>

static inline void _hb_memory_barrier ()
{
#if !defined(MemoryBarrier)
  /* MinGW has a convoluted history of supporting MemoryBarrier. */
  LONG dummy = 0;
  InterlockedExchange (&dummy, 1);
#else
  MemoryBarrier ();
#endif
}
#define _hb_memory_barrier()                    _hb_memory_barrier ()

#define hb_atomic_int_impl_add(AI, V)           InterlockedExchangeAdd ((LONG *) (AI), (V))
static_assert ((sizeof (LONG) == sizeof (int)), "");

#define hb_atomic_ptr_impl_cmpexch(P,O,N)       (InterlockedCompareExchangePointer ((P), (N), (O)) == (O))


#elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)

#define _hb_memory_barrier()                    __sync_synchronize ()

#define hb_atomic_int_impl_add(AI, V)           __sync_fetch_and_add ((AI), (V))

#define hb_atomic_ptr_impl_cmpexch(P,O,N)       __sync_bool_compare_and_swap ((P), (O), (N))


#elif !defined(HB_NO_MT) && defined(HAVE_SOLARIS_ATOMIC_OPS)

#include <atomic.h>
#include <mbarrier.h>

#define _hb_memory_r_barrier()                  __machine_r_barrier ()
#define _hb_memory_w_barrier()                  __machine_w_barrier ()
#define _hb_memory_barrier()                    __machine_rw_barrier ()

static inline int _hb_fetch_and_add (int *AI, int V)
{
  _hb_memory_w_barrier ();
  int result = atomic_add_int_nv ((uint_t *) AI, V) - V;
  _hb_memory_r_barrier ();
  return result;
}
static inline bool _hb_compare_and_swap_ptr (void **P, void *O, void *N)
{
  _hb_memory_w_barrier ();
  bool result = atomic_cas_ptr (P, O, N) == O;
  _hb_memory_r_barrier ();
  return result;
}

#define hb_atomic_int_impl_add(AI, V)           _hb_fetch_and_add ((AI), (V))

#define hb_atomic_ptr_impl_cmpexch(P,O,N)       _hb_compare_and_swap_ptr ((P), (O), (N))


#elif !defined(HB_NO_MT) && defined(__APPLE__)

#include <libkern/OSAtomic.h>
#ifdef __MAC_OS_X_MIN_REQUIRED
#include <AvailabilityMacros.h>
#elif defined(__IPHONE_OS_MIN_REQUIRED)
#include <Availability.h>
#endif

#define _hb_memory_barrier()                    OSMemoryBarrier ()

#define hb_atomic_int_impl_add(AI, V)           (OSAtomicAdd32Barrier ((V), (AI)) - (V))

#if (MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4 || __IPHONE_VERSION_MIN_REQUIRED >= 20100)
#define hb_atomic_ptr_impl_cmpexch(P,O,N)       OSAtomicCompareAndSwapPtrBarrier ((O), (N), (P))
#else
#if __ppc64__ || __x86_64__ || __aarch64__
#define hb_atomic_ptr_impl_cmpexch(P,O,N)       OSAtomicCompareAndSwap64Barrier ((int64_t) (O), (int64_t) (N), (int64_t*) (P))
#else
#define hb_atomic_ptr_impl_cmpexch(P,O,N)       OSAtomicCompareAndSwap32Barrier ((int32_t) (O), (int32_t) (N), (int32_t*) (P))
#endif
#endif


#elif !defined(HB_NO_MT) && defined(_AIX) && (defined(__IBMCPP__) || defined(__ibmxl__))

#include <builtins.h>

#define _hb_memory_barrier()                    __lwsync ()

static inline int _hb_fetch_and_add (int *AI, int V)
{
  _hb_memory_barrier ();
  int result = __fetch_and_add (AI, V);
  _hb_memory_barrier ();
  return result;
}
static inline bool _hb_compare_and_swaplp (long *P, long O, long N)
{
  _hb_memory_barrier ();
  bool result = __compare_and_swaplp (P, &O, N);
  _hb_memory_barrier ();
  return result;
}

#define hb_atomic_int_impl_add(AI, V)           _hb_fetch_and_add ((AI), (V))

#define hb_atomic_ptr_impl_cmpexch(P,O,N)       _hb_compare_and_swaplp ((long *) (P), (long) (O), (long) (N))
static_assert ((sizeof (long) == sizeof (void *)), "");


#elif !defined(HB_NO_MT)

#define HB_ATOMIC_INT_NIL 1 /* Warn that fallback implementation is in use. */

#define _hb_memory_barrier()

#define hb_atomic_int_impl_add(AI, V)           ((*(AI) += (V)) - (V))

#define hb_atomic_ptr_impl_cmpexch(P,O,N)       (* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false)


#else /* HB_NO_MT */

#define hb_atomic_int_impl_add(AI, V)           ((*(AI) += (V)) - (V))

#define _hb_memory_barrier()

#define hb_atomic_ptr_impl_cmpexch(P,O,N)       (* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false)


#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


#define HB_ATOMIC_INT_INIT(V)          {V}
struct hb_atomic_int_t
{
  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;
};


#define HB_ATOMIC_PTR_INIT(V)          {V}
template <typename P>
struct hb_atomic_ptr_t
{
  typedef typename hb_remove_pointer (P) T;

  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;
};


#endif /* HB_ATOMIC_HH */