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// Copyright 2003, Google Inc.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//  1. Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//  2. Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//  3. Neither the name of Google Inc. nor the names of its contributors may be
//     used to endorse or promote products derived from this software without
//     specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
// EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
// OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Implementation of atomic operations for x86 on msvc.  This file should not
// be included directly.  Clients should instead include "atomicops.h".

#ifndef GEARS_BASE_COMMON_ATOMIC_OPS_WIN32_H__
#define GEARS_BASE_COMMON_ATOMIC_OPS_WIN32_H__

#include <windows.h>
#include <crtdefs.h>  // for intptr_t on WINCE

typedef intptr_t AtomicWord;
#ifdef _WIN64
typedef LONG Atomic32;
#else
typedef AtomicWord Atomic32;
#endif

// TODO(aa): we don't have COMPILE_ASSERT in Gears.
// COMPILE_ASSERT(sizeof(AtomicWord) == sizeof(PVOID), atomic_word_is_atomic);

inline AtomicWord CompareAndSwap(volatile AtomicWord* ptr,
                                 AtomicWord old_value,
                                 AtomicWord new_value) {
  PVOID result = InterlockedCompareExchangePointer(
    reinterpret_cast<volatile PVOID*>(ptr),
    reinterpret_cast<PVOID>(new_value), reinterpret_cast<PVOID>(old_value));
  return reinterpret_cast<AtomicWord>(result);
}

inline AtomicWord AtomicExchange(volatile AtomicWord* ptr,
                                 AtomicWord new_value) {
  PVOID result = InterlockedExchangePointer(
    const_cast<PVOID*>(reinterpret_cast<volatile PVOID*>(ptr)),
    reinterpret_cast<PVOID>(new_value));
  return reinterpret_cast<AtomicWord>(result);
}

#ifdef _WIN64
inline Atomic32 AtomicIncrement(volatile Atomic32* ptr, Atomic32 increment) {
  // InterlockedExchangeAdd returns *ptr before being incremented
  // and we must return nonzero iff *ptr is nonzero after being
  // incremented.
  return InterlockedExchangeAdd(ptr, increment) + increment;
}

inline AtomicWord AtomicIncrement(volatile AtomicWord* ptr,
                                  AtomicWord increment) {
  return InterlockedExchangeAdd64(
    reinterpret_cast<volatile LONGLONG*>(ptr),
    static_cast<LONGLONG>(increment)) + increment;
}
#else
inline AtomicWord AtomicIncrement(volatile AtomicWord* ptr,
                                  AtomicWord increment) {
  return InterlockedExchangeAdd(
#ifdef WINCE
      // It seems that for WinCE InterlockedExchangeAdd takes LONG* as its first
      // parameter. The const_cast is required to remove the volatile modifier.
      const_cast<LONG*>(reinterpret_cast<volatile LONG*>(ptr)),
#else
      reinterpret_cast<volatile LONG*>(ptr),
#endif
      static_cast<LONG>(increment)) + increment;
}
#endif

#endif  // GEARS_BASE_COMMON_ATOMIC_OPS_WIN32_H__