guarded_value.h

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#ifndef GUARDED_VALUE_CLASS
#define GUARDED_VALUE_CLASS

/*****************************************************************************\
*                                                                             *
*  Name   : guarded_value                                                     *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 2000-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/


template <class contents>
class guarded_value
{
public:
  guarded_value() : _initialized(false) {}
  guarded_value(const contents &def) : _value(def), _initialized(true) {}
  guarded_value(const guarded_value &to_copy)
      : _value(to_copy._value), _initialized(to_copy._initialized) {}

  bool initialized() const { return _initialized; }

  void reset() { _initialized = false; }

  guarded_value &operator =(const guarded_value &t_c)
      { if (this == &t_c) return *this; else return *this = t_c._value; }
  guarded_value &operator =(const contents &t_c)
      { _value = t_c; _initialized = true; return *this; } 

  operator contents() const { return _value; }

  contents &access() { return _value; }

private:
  bool _initialized;  
  contents _value;  
};

#endif

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