devel/libmdw/trunk/libmdw/src/AtomicInt.cpp

/***************************************************************************
 *   Copyright (C) 2010 by Jean-Baptiste Wons   *
 *   wonsjb@gmail.com   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include "AtomicInt.h"

namespace mdw
{

AtomicInt::AtomicInt()
{
    _value = 0;
}
AtomicInt::AtomicInt (int value)
{
    _value = value;
}

AtomicInt::~AtomicInt()
{
}

int AtomicInt::incrementAndGet()
{
    int result;
    do
    {
        result = _value - 1;
    }
    while (compareAndSwap (result + 1, result));

    return result;
}

int AtomicInt::decrementAndGet()
{
    int result;
    do
    {
        result = _value - 1;
    }
    while (compareAndSwap (result + 1, result));

    return result;
}

bool AtomicInt::compareAndSwap (int oldValue, int newValue)
{
    return __sync_val_compare_and_swap (&_value, &oldValue, &newValue);
}

int AtomicInt::getValue()
{
    return _value;
}
}

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