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OCCT/src/NCollection/NCollection_Comparator.hxx

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// File NCollection_Comparator.hxx
// Created 27 January 2011
// Author KGV
// Copyright OpenCASCADE 2011
#ifndef _NCollection_Comparator_HeaderFile
#define _NCollection_Comparator_HeaderFile
#include <Precision.hxx>
/**
* Class to define basic compare operations.
* Basic implementation use redirection to standard C++ operators.
* You can use standard C++ templates mechanisms to redefine these methods
* or to inherit basic implementation to create multiple comparators
* for same type with different rules.
*/
template<class TheItemType>
class NCollection_Comparator
{
public:
NCollection_Comparator (const Standard_Real theTolerance = Precision::Confusion())
: myTolerance (theTolerance) {}
virtual ~NCollection_Comparator() {}
public:
//! Comparison functions which should be overridden
//! if standard operators are not defined for user type.
//! Should return true if Left value is greater than Right
virtual Standard_Boolean IsGreater (const TheItemType& theLeft, const TheItemType& theRight) const
{
return theLeft > theRight;
}
//! Should return true if values are equal
virtual Standard_Boolean IsEqual (const TheItemType& theLeft, const TheItemType& theRight) const
{
return theLeft == theRight;
}
public:
//! Comparison functions which may be overridden for performance reasons
//! Should return true if Left value is lower than Right
virtual Standard_Boolean IsLower (const TheItemType& theLeft, const TheItemType& theRight) const
{
return !IsGreater (theLeft, theRight) && !IsEqual (theLeft, theRight);
}
virtual Standard_Boolean IsLowerEqual (const TheItemType& theLeft, const TheItemType& theRight) const
{
return !IsGreater (theLeft, theRight);
}
virtual Standard_Boolean IsGreaterEqual (const TheItemType& theLeft, const TheItemType& theRight) const
{
return IsGreater (theLeft, theRight) || IsEqual (theLeft, theRight);
}
protected:
Standard_Real myTolerance;
};
#endif /*_NCollection_Comparator_HeaderFile*/