arithop.cc

在LINUX下运行的仿真机器人服务器源代码

// -*-c++-*-

/***************************************************************************
                                 arithop.cc  
                  Flyweight classes representing comparison operators
                             -------------------
    begin                : 22-MAR-2002
    copyright            : (C) 2002 by The RoboCup Soccer Server 
                           Maintainance Group.
    email                : [e-mail]
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU LGPL as published by the Free Software  *
 *   Foundation; either version 2 of the License, or (at your option) any  *
 *   later version.                                                        *
 *                                                                         *
 ***************************************************************************/

#include "arithop.h"


namespace rcss
{
  namespace util
  {
    const char* ArithOp::STRINGS[] = { "+", "-", "*", "/" };

    ArithOp::ArithOp( const arith_t& arith )
      : M_arith( arith )
    {}

    const char*
    ArithOp::getStr() const
    {
        return STRINGS[ M_arith ]; 
    }

    const ArithOp&
    ArithOp::instance( const arith_t& arith )
    {
      // The entire collection of ArithOps is created on the first
      // call to ArithOp::instance.  Because the array is a static
      // varaible in this function, we can legally return references
      // to its elements.  One of the advatages of doing this is
      // that the ArithOps will be destroyed automatically.
      static ArithOp instances[] = { ArithOp( PLUS ),
                                     ArithOp( MINUS ),
                                     ArithOp( MULT ),
                                     ArithOp( DIV ) };
      return instances[ arith ];
    }

    const ArithOp&
    ArithOp::plus()
    { return instance( PLUS ); }
    
    const ArithOp&
    ArithOp::minus()
    { return instance( MINUS ); }
    
    const ArithOp&
    ArithOp::mult()
    { return instance( MULT ); }
    
    const ArithOp&
    ArithOp::div()
    { return instance( DIV ); }
  }
}