#ifndef TAU_CONSTANT_FUNCTION_1_19_2007
#define TAU_CONSTANT_FUNCTION_1_19_2007
/**
    @file TauConstant.h
    @author Brian Magill
    @datecreated 1/19/2007

    $Date:$
    $Revision:$

    @copyright
     (©) Copyright 2006 by GATS Inc.
     11864 Canon Blvd., Suite 101, Newport News, VA 23606

     All Rights Reserved. No part of this software or publication may be
     reproduced, stored in a retrieval system, or transmitted, in any form
     or by any means, electronic, mechanical, photocopying, recording, or
     otherwise without the prior written permission of GATS Inc.

    @brief: Calculates what the refraction angle was (t - tau) ago    
 
    Overall TauConstant is a helper class to CalcRefraction.  
    Assumes that time and refraction values are inserted in 
    montonically increasing time.
    
*/
//----------------------------------------------------------------------
//
#include "AbstractTauFunction.h"
#include <valarray>
#include <iostream>

class TauConstant: public AbstractTauFunction
{

private:

    double timeLag;    
    
public:

    TauConstant(double t=0.0):timeLag(t) { };
    
    TauConstant(TauConstant const& rhs):timeLag(rhs.timeLag) { };
    
    TauConstant& operator = (TauConstant const& rhs )
        {
        if (this == &rhs)
            return *this;

        timeLag = rhs.timeLag;  

        return *this;                                
        };        

    ~TauConstant() { };    

    double operator( )(double const & currentTime) const { return timeLag; };   

    void dump() const {std::cout << "Tau time lag = " << timeLag << std::endl; };
    
};        

#endif