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#ifndef _ATOMIC_INT_APPLE_H
#define _ATOMIC_INT_APPLE_H
#include <libkern/OSAtomic.h>
//http://developer.apple.com/library/mac/#documentation/Darwin/Reference/KernelIOKitFramework/OSAtomic_h/index.html
namespace mt{
class atomicInt
{
private:
volatile int _q_value;
public:
atomicInt()
{
_q_value = 0;
}
atomicInt( int value )
{
_q_value = value;
}
// atomic API
/**
Reads the current value of this QAtomicInt and then adds valueToAdd
to the current value, returning the original value.
Unfortunately, MacOSX does not provide with fetch-and-add functions,
only add-and-fetch. Therefore, we have to simulate them.
Implementation based on SDL:
//http://lists.libsdl.org/pipermail/commits-libsdl.org/2011-January/003568.html
*/
inline int fetchAndAddAcquire( int valueToAdd )
{
//T *originalValue = currentValue;
//currentValue += valueToAdd;
//return originalValue;
int originalValue;
do {
originalValue = _q_value;
} while (!OSAtomicCompareAndSwap32Barrier(originalValue, originalValue+valueToAdd, &_q_value));
return originalValue;
}
/**
Atomically increments the value of this atomicInt.
Returns true if the new value is non-zero, false otherwise.*/
inline bool ref()
{
return OSAtomicIncrement32Barrier(&_q_value) != 0;
}
/*
Atomically decrements the value of this QAtomicInt.
Returns true if the new value is non-zero, false otherwise.*/
inline bool deref()
{
return OSAtomicDecrement32Barrier(&_q_value) != 0;
}
/*
If the current _q_value of this QAtomicInt is the expectedValue,
the test-and-set functions assign the newValue to this QAtomicInt
and return true. If the values are not the same, this function
does nothing and returns false.
*/
inline bool testAndSetOrdered(int expectedValue, int newValue)
{
//if (currentValue == expectedValue) {
// currentValue = newValue;
// return true;
// }
//return false;
return OSAtomicCompareAndSwap32Barrier(expectedValue, newValue, &_q_value);
}
// Non-atomic API
inline bool operator==(int value) const
{
return _q_value == value;
}
inline bool operator!=(int value) const
{
return _q_value != value;
}
inline bool operator!() const
{
return _q_value == 0;
}
inline operator int() const
{
return _q_value;
}
inline atomicInt &operator=(int value)
{
_q_value = value;
return *this;
}
inline bool operator>(int value) const
{
return _q_value > value;
}
inline bool operator<(int value) const
{
return _q_value < value;
}
};
}//namespace
#endif
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