deferrer.hh

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// deferrer.hh: this file is part of the Vaucanson project.
//
// Vaucanson, a generic library for finite state machines.
//
// Copyright (C) 2004, 2005 The Vaucanson Group.
//
// 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.
//
// The complete GNU General Public Licence Notice can be found as the
// `COPYING' file in the root directory.
//
// The Vaucanson Group consists of people listed in the `AUTHORS' file.
//
#ifndef VCSN_MISC_DEFERRER_HH
# define VCSN_MISC_DEFERRER_HH
 
namespace utility
{

# ifndef VCSN_NDEBUG
  enum { deferrer_runtime_checks_default = true };
#  else // VCSN_NDEBUG
  enum { deferrer_runtime_checks_default = false };
# endif // ! VCSN_NDEBUG


  template <class T, bool B>
  struct DeferrerDebugPart
  {
  protected:
    // Defaults to true.
    DeferrerDebugPart(void* ptr, bool is_valid = false);

    void        set_valid(bool b);
    T&          cast(void*);
    const T&    cast(const void*) const;

    bool is_valid_;
  };

  template <class T>
  struct DeferrerDebugPart<T, false>
  {
  protected:
    // False version.
    DeferrerDebugPart(void* ptr, bool is_valid = false);
    void        set_valid(bool b);
     T&         cast(void*);
     const T&   cast(const void*) const;
  };
  template <class T, bool rt_checks = deferrer_runtime_checks_default>
  struct Deferrer : DeferrerDebugPart<T, rt_checks>
  {
    typedef T deferred_type;

    Deferrer();

    Deferrer&
    operator = (const deferred_type&);

    operator T () const;
  protected:
    typedef unsigned char data_t[sizeof (deferred_type)];

    data_t data;
  };

} // End of namespace utility.

# ifndef VCSN_USE_INTERFACE_ONLY
#  include <vaucanson/misc/deferrer.hxx>
# endif // VCSN_USE_INTERFACE_ONLY

#endif // ! VCSN_MISC_DEFERRER_HH

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