1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
3 * This file is a part of LEMON, a generic C++ optimization library.
5 * Copyright (C) 2003-2008
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
19 // This file contains a modified version of the enable_if library from BOOST.
20 // See the appropriate copyright notice below.
22 // Boost enable_if library
24 // Copyright 2003 (c) The Trustees of Indiana University.
26 // Use, modification, and distribution is subject to the Boost Software
27 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
28 // http://www.boost.org/LICENSE_1_0.txt)
30 // Authors: Jaakko Jarvi (jajarvi at osl.iu.edu)
31 // Jeremiah Willcock (jewillco at osl.iu.edu)
32 // Andrew Lumsdaine (lums at osl.iu.edu)
35 #ifndef LEMON_BITS_ENABLE_IF_H
36 #define LEMON_BITS_ENABLE_IF_H
39 //\brief Miscellaneous basic utilities
44 // Basic type for defining "tags". A "YES" condition for \c enable_if.
46 // Basic type for defining "tags". A "YES" condition for \c enable_if.
51 static const bool value = true;
54 // Basic type for defining "tags". A "NO" condition for \c enable_if.
56 // Basic type for defining "tags". A "NO" condition for \c enable_if.
61 static const bool value = false;
69 Wrap(const T &t) : value(t) {}
72 /**************** dummy class to avoid ambiguity ****************/
74 template<int T> struct dummy { dummy(int) {} };
76 /**************** enable_if from BOOST ****************/
78 template <typename Type, typename T = void>
84 template <bool B, class T = void>
90 struct enable_if_c<false, T> {};
92 template <class Cond, class T = void>
93 struct enable_if : public enable_if_c<Cond::value, T> {};
95 template <bool B, class T>
96 struct lazy_enable_if_c {
97 typedef typename T::type type;
101 struct lazy_enable_if_c<false, T> {};
103 template <class Cond, class T>
104 struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
107 template <bool B, class T = void>
108 struct disable_if_c {
113 struct disable_if_c<true, T> {};
115 template <class Cond, class T = void>
116 struct disable_if : public disable_if_c<Cond::value, T> {};
118 template <bool B, class T>
119 struct lazy_disable_if_c {
120 typedef typename T::type type;
124 struct lazy_disable_if_c<true, T> {};
126 template <class Cond, class T>
127 struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};