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#include <stdio.h>

#include "qglobal.h"

#include "qmutex.h"

#include "qmutex_p.h"

QMutex::QMutex() : d(new QMutexPrivate())

{

}

QMutex::~QMutex()

{

  delete d;

}

void QMutex::lock()

{

    //printf("%p: QMutex::lock(): enter\n",this);

    bool isLocked;

    isLocked = d->contenders.testAndSet(0, 1);

    if (!isLocked)

    {

      isLocked = d->contenders.fetchAndAdd(1)==0;

      if (!isLocked)

      {

        // didn't get the lock, wait for it

        //printf("%p: QMutex::lock(): wait() %d\n",this,(int)d->contenders);

        d->wait();

        // release lock

        d->contenders.fetchAndAdd(-1);

      }

    }

    //printf("%p: QMutex::lock(): leave\n",this);

}

bool QMutex::tryLock()

{

    bool isLocked = d->contenders.testAndSet(0, 1);

    return isLocked;

}

void QMutex::unlock()

{

    //printf("%p: QMutex::unlock(): enter %d\n",this,(int)d->contenders);

    if (!d->contenders.testAndSet(1, 0))

    {

         //printf("%p: QMutex::unlock(): wakeUp()\n",this);

         d->wakeUp();

    }

    //printf("%p: QMutex::unlock(): leave\n",this);

}