/*
 * 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(_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_INIT(V) (V)
#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(__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_INIT(V) (V)
#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) (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(HAVE_INTEL_ATOMIC_PRIMITIVES)

typedef int hb_atomic_int_impl_t;
#define HB_ATOMIC_INT_IMPL_INIT(V) (V)
#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_INIT(V) (V)
#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)

#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_INIT(V) (V)
#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_INIT(V)              (V)
#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


#define HB_ATOMIC_INT_INIT(V)           {HB_ATOMIC_INT_IMPL_INIT(V)}

struct hb_atomic_int_t
{
  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 (const_cast<hb_atomic_int_impl_t &> (v),  1); }
  inline int dec (void) { return hb_atomic_int_impl_add (const_cast<hb_atomic_int_impl_t &> (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 */