expradapter.h

精确的函数表达模板,里面包含了许多C和C++的函数表达模板

/****************************************************************************
 * Copyright (C) 2001        Piece Wise Functions
 *                           Carlo Galotto
 *                           Italy
 *                           Email: [e-mail]
 *                                  [e-mail]
 *
 *
 * This framework is free  software; you can  redistribute it and/or modify
 * it. This framework is distributed  in the  hope  that  it  will  be useful,
 * but WITHOUT ANY WARRANTY;  without even the   implied  warranty of
 * MERCHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.
 * The proposed framework is based upon the paper "Expression Templates" by
 * Todd Veldhuizen.
 ****************************************************************************/

// Class: ExprAdapter

#ifndef __EXPRADPT_H          //Required for current class
  #define __EXPRADPT_H


#ifndef __EXPRINTR_H          //Required for base classes
  #include "ExprInterface.h"
#endif

   // Concrete Expression (ADAPTER pattern)
   template <class exprT>
   class ExprAdapter
      : public ExprInterface< typename exprT::argument_type
                             ,typename exprT::result_type >
   {
      public:
         typedef typename exprT expr_type;
         typedef typename exprT::argument_type argument_type;
         typedef typename exprT::result_type   result_type;

      private:
         exprT expr;

      public:

         // Conversion constructor
         ExprAdapter(const exprT& e) : expr(e) { ; }

         // Copy Constructor
         ExprAdapter(const ExprAdapter& anExprAdapter) : expr(anExprAdapter.expr) {}

         // Clone
         ExprInterface<argument_type, result_type>* clone() const
            { return new ExprAdapter(*this); }

	      //Operator=
         ExprAdapter& operator= (const ExprAdapter& anExprAdapter)
         {
            if(&anExpr != this)  expr = anExprAdapter.expr;
            return *this;
         }

         // Evaluator
         result_type operator() (const argument_type& x) const {return expr(x); }

         // Destructor
         virtual ~ExprAdapter() { }
   };

#endif