amxmodx/public/amtl/am-atomics.h

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2014-05-03 15:00:21 +04:00
// vim: set sts=8 ts=2 sw=2 tw=99 et:
//
// Copyright (C) 2013, David Anderson and AlliedModders LLC
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// * 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.
// * Neither the name of AlliedModders LLC 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
#ifndef _include_amtl_atomics_h_
#define _include_amtl_atomics_h_
#include <am-utility.h>
namespace ke {
#if defined(_MSC_VER)
extern "C" {
long __cdecl _InterlockedIncrement(long volatile *dest);
long __cdecl _InterlockedDecrement(long volatile *dest);
}
# pragma intrinsic(_InterlockedIncrement)
# pragma intrinsic(_InterlockedDecrement)
#endif
template <size_t Width>
struct AtomicOps;
template <>
struct AtomicOps<4>
{
#if defined(_MSC_VER)
typedef long Type;
static Type Increment(Type *ptr) {
return _InterlockedIncrement(ptr);
}
static Type Decrement(Type *ptr) {
return _InterlockedDecrement(ptr);
};
#elif defined(__GNUC__)
typedef int Type;
// x86/x64 notes: When using GCC < 4.8, this will compile to a spinlock.
// On 4.8+, or when using Clang, we'll get the more optimal "lock addl"
// variant.
static Type Increment(Type *ptr) {
return __sync_add_and_fetch(ptr, 1);
}
static Type Decrement(Type *ptr) {
return __sync_sub_and_fetch(ptr, 1);
}
#endif
};
class AtomicRefCount
{
typedef AtomicOps<sizeof(uintptr_t)> Ops;
public:
AtomicRefCount(uintptr_t value)
: value_(value)
{
}
void increment() {
Ops::Increment(&value_);
}
// Return false if all references are gone.
bool decrement() {
return Ops::Decrement(&value_) != 0;
}
private:
Ops::Type value_;
};
}
#endif // _include_amtl_atomics_h_