/* -*- C++ -*- * lemon/utility.h - Part of LEMON, a generic C++ optimization library * * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi * Kutatocsoport (Egervary Research Group on Combinatorial Optimization, * EGRES). * * Permission to use, modify and distribute this software is granted * provided that this copyright notice appears in all copies. For * precise terms see the accompanying LICENSE file. * * This software is provided "AS IS" with no warranty of any kind, * express or implied, and with no claim as to its suitability for any * purpose. * * This file contains a modified version of the enable_if library from BOOST. * See the appropriate copyright notice below. */ // Boost enable_if library // Copyright 2003 © The Trustees of Indiana University. // Use, modification, and distribution is subject to the Boost Software // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) // Authors: Jaakko Järvi (jajarvi at osl.iu.edu) // Jeremiah Willcock (jewillco at osl.iu.edu) // Andrew Lumsdaine (lums at osl.iu.edu) #ifndef LEMON_UTILITY_H #define LEMON_UTILITY_H ///\file ///\brief Miscellaneous basic utilities /// ///\todo Please rethink the organisation of the basic files like this. ///E.g. this file might be merged with invalid.h. namespace lemon { /// Basic type for defining "tags". A "YES" condition for \c enable_if. /// Basic type for defining "tags". A "YES" condition for \c enable_if. /// ///\sa False /// /// \todo This should go to a separate "basic_types.h" (or something) /// file. struct True { ///\e static const bool value = true; }; /// Basic type for defining "tags". A "NO" condition for \c enable_if. /// Basic type for defining "tags". A "NO" condition for \c enable_if. /// ///\sa True struct False { ///\e static const bool value = false; }; template struct Wrap { const T &value; Wrap(const T &t) : value(t) {} }; /**************** dummy class to avoid ambiguity ****************/ template struct dummy { dummy(int) {} }; /**************** enable_if from BOOST ****************/ template struct enable_if_c { typedef T type; }; template struct enable_if_c {}; template struct enable_if : public enable_if_c {}; template struct lazy_enable_if_c { typedef typename T::type type; }; template struct lazy_enable_if_c {}; template struct lazy_enable_if : public lazy_enable_if_c {}; template struct disable_if_c { typedef T type; }; template struct disable_if_c {}; template struct disable_if : public disable_if_c {}; template struct lazy_disable_if_c { typedef typename T::type type; }; template struct lazy_disable_if_c {}; template struct lazy_disable_if : public lazy_disable_if_c {}; // smart referencing template struct SmartReference { typedef _Type& Type; }; template struct SmartReference< _Type, typename enable_if::type > { typedef _Type Type; }; template struct SmartConstReference { typedef const _Type& Type; }; template struct SmartConstReference< _Type, typename enable_if::type > { typedef const _Type Type; }; template struct SmartParameter { typedef _Type& Type; }; template struct SmartParameter< _Type, typename enable_if::type > { typedef const _Type& Type; }; } // namespace lemon #endif