//! @copyright *this file is freware. 
//! @warning  Use it at your own risk.
//! @file identity.hpp
//! @author Dejan D. M. Milosavljevic
//! @version 1.0
//! @date 2003
//! @please "Do not remove or change this comments"
//! @description indentity classes.
//! @bug 
//! @warning  Use it at your own risk.
//! @copyright *this file is freware. 

#ifndef Dh_DDMRM_identyty_function_HPP_
 #define Dh_DDMRM_identyty_function_HPP_

 #include <functional>
  
 namespace stl_ext
  {
   template< typename N_argument, typename N_return = N_argument>
    class  identity_copy
     : std::unary_function< N_argument const&,  N_return >
     {
      public:
       typedef N_return   result_type;
       typedef N_argument argument_type;

       result_type operator()( argument_type  P_argument )
        {
         return P_argument;
        }
  
     };


   template< typename N_argument, typename N_return = N_argument >
    class  identity_original
     : public std::unary_function< N_argument &,  N_return& >
     {
      public:
       typedef N_return   &   result_type;
       typedef N_argument &   argument_type;

       result_type operator()( argument_type P_argument )
        {
         return P_argument;
        }
     };

   
   template< typename N_return >
    class  identity_convert
     : public std::unary_function< N_return,  N_return >
     {
      public:

       typedef N_return  result_type;
       

       template < typename N1_argument >
        result_type operator()( N1_argument const & P_argument )
         {
          return P_argument;
         }
     };

  }

#endif