/*
 * 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_PRIVATE_HH
#define HB_ATOMIC_PRIVATE_HH

#include "hb-private.hh"


/* atomic_int */

/* 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; must have typedef'ed hb_atomic_int_impl_t as well. */


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

/* C++11-style GCC primitives. */

typedef int hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		__atomic_fetch_add (&(AI), (V), __ATOMIC_ACQ_REL)

#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>

typedef int hb_atomic_int_impl_t;
#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_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) || defined(__CYGWIN__))

#include <windows.h>

/* MinGW has a convoluted history of supporting MemoryBarrier
 * properly.  As such, define a function to wrap the whole
 * thing. */
static inline void _HBMemoryBarrier (void) {
#if !defined(MemoryBarrier)
  long dummy = 0;
  InterlockedExchange (&dummy, 1);
#else
  MemoryBarrier ();
#endif
}

typedef LONG hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		InterlockedExchangeAdd (&(AI), (V))

#define hb_atomic_ptr_impl_get(P)		(_HBMemoryBarrier (), (void *) *(P))
#define hb_atomic_ptr_impl_cmpexch(P,O,N)	(InterlockedCompareExchangePointer ((void **) (P), (void *) (N), (void *) (O)) == (void *) (O))


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

typedef int hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		__sync_fetch_and_add (&(AI), (V))

#define hb_atomic_ptr_impl_get(P)		(void *) (__sync_synchronize (), *(P))
#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>

typedef unsigned int hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		( ({__machine_rw_barrier ();}), atomic_add_int_nv (&(AI), (V)) - (V))

#define hb_atomic_ptr_impl_get(P)		( ({__machine_rw_barrier ();}), (void *) *(P))
#define hb_atomic_ptr_impl_cmpexch(P,O,N)	( ({__machine_rw_barrier ();}), atomic_cas_ptr ((void **) (P), (void *) (O), (void *) (N)) == (void *) (O) ? true : false)


#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


typedef int32_t hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		(OSAtomicAdd32Barrier ((V), &(AI)) - (V))

#define hb_atomic_ptr_impl_get(P)		(OSMemoryBarrier (), (void *) *(P))
#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 ((void *) (O), (void *) (N), (void **) (P))
#else
#if __ppc64__ || __x86_64__ || __aarch64__
#define hb_atomic_ptr_impl_cmpexch(P,O,N)	OSAtomicCompareAndSwap64Barrier ((int64_t) (void *) (O), (int64_t) (void *) (N), (int64_t*) (P))
#else
#define hb_atomic_ptr_impl_cmpexch(P,O,N)	OSAtomicCompareAndSwap32Barrier ((int32_t) (void *) (O), (int32_t) (void *) (N), (int32_t*) (P))
#endif
#endif


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

#include <builtins.h>


static inline int _hb_fetch_and_add(volatile int* AI, unsigned int V) {
  __lwsync();
  int result = __fetch_and_add(AI, V);
  __isync();
  return result;
}
static inline int _hb_compare_and_swaplp(volatile long* P, long O, long N) {
  __sync();
  int result = __compare_and_swaplp (P, &O, N);
  __sync();
  return result;
}

typedef int hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)           _hb_fetch_and_add (&(AI), (V))

#define hb_atomic_ptr_impl_get(P)               (__sync(), (void *) *(P))
#define hb_atomic_ptr_impl_cmpexch(P,O,N)       _hb_compare_and_swaplp ((long*)(P), (long)(O), (long)(N))

#elif !defined(HB_NO_MT)

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

typedef volatile int hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		(((AI) += (V)) - (V))

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


#else /* HB_NO_MT */

typedef int hb_atomic_int_impl_t;
#define hb_atomic_int_impl_add(AI, V)		(((AI) += (V)) - (V))

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


#endif


#ifndef HB_ATOMIC_INT_INIT
#define HB_ATOMIC_INT_INIT(V)          {V}
#endif

struct hb_atomic_int_t
{
  mutable hb_atomic_int_impl_t v;

  inline void set_unsafe (int v_) { v = v_; }
  inline int get_unsafe (void) const { return v; }
  inline int inc (void) { return hb_atomic_int_impl_add (v,  1); }
  inline int dec (void) { return hb_atomic_int_impl_add (v, -1); }
};


#define hb_atomic_ptr_get(P) hb_atomic_ptr_impl_get(P)
#define hb_atomic_ptr_cmpexch(P,O,N) hb_atomic_ptr_impl_cmpexch((P),(O),(N))


#endif /* HB_ATOMIC_PRIVATE_HH */