base::xorptr_t< T > Class Template Reference

xorptr_t encapsulate "safely" the concept of swapping between 2 pointers with a xor operation. More...

#include <xorptr.h>

List of all members.

Public Member Functions
	xorptr_t (T *ptr1, T *ptr2)
	Constructor: supperpose internal values ptr1 and ptr2.
T *	swap (T *fromPtr) const
	Swap pointer (between ptr1 and ptr2 used originally).
Private Attributes
uintptr_t	ptr1xor2
	supperposition of 2 pointers

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Detailed Description

template<class T>
class base::xorptr_t< T >

xorptr_t encapsulate "safely" the concept of swapping between 2 pointers with a xor operation.

Xor between a pointer and an int: sounds scary but it is a very efficient way to swap 2 pointers:

• init ptr to ptr1
• init xorPtr to ptr1 ^ ptr2
• swaping between ptr1 and ptr2 is now equivalent to ptr ^= xorPtr, which is done without jump + we need to store only one xorPtr and not ptr1 and ptr2.

The original idea of supperposing 2 states into one (here 2 pointers) in such a way that you get information on one state only by observing the other state comes from quantum mechanics.

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Constructor & Destructor Documentation

template<class T> base::xorptr_t< T >::xorptr_t (  T *  ptr1, T *  ptr2 )  [inline]

Constructor: supperpose internal values ptr1 and ptr2. Parameters: ptr1,ptr2,:  pointers to swap between.

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Member Function Documentation

template<class T> T* base::xorptr_t< T >::swap (  T *  fromPtr  )  const [inline]

Swap pointer (between ptr1 and ptr2 used originally). Returns: ptr1 if fromPtr == ptr2 or ptr2 if fromPtr == ptr1 Precondition: fromPtr == ptr1 or ptr2

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Member Data Documentation

template<class T> uintptr_t base::xorptr_t< T >::ptr1xor2 [private]

supperposition of 2 pointers

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The documentation for this class was generated from the following file:

• /home/adavid/UPPAAL/trunk/server/modules/include/base/xorptr.h

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