COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/utility.h @ 1284:b941d044f87b

Last change on this file since 1284:b941d044f87b was 1270:806451fd084b, checked in by jacint, 15 years ago

bugfixes in doc

File size: 2.8 KB
Line 
1/* -*- C++ -*-
2 *
3 * src/lemon/utility.h - Part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi
6 * Kutatocsoport (Egervary Combinatorial Optimization Research Group,
7 * EGRES).
8 *
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.
12 *
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
15 * purpose.
16 *
17 * This file contains a modified version of the enable_if library from BOOST.
18 * See the appropriate copyright notice below.
19 */
20
21// Boost enable_if library
22
23// Copyright 2003 © The Trustees of Indiana University.
24
25// Use, modification, and distribution is subject to the Boost Software
26// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
27// http://www.boost.org/LICENSE_1_0.txt)
28
29//    Authors: Jaakko Järvi (jajarvi at osl.iu.edu)
30//             Jeremiah Willcock (jewillco at osl.iu.edu)
31//             Andrew Lumsdaine (lums at osl.iu.edu)
32
33
34#ifndef LEMON_UTILITY_H
35#define LEMON_UTILITY_H
36
37namespace lemon
38{
39
40  /// Basic type for defining "tags". A "YES" condition for enable_if.
41
42  /// \todo This should go to a separate "basic_types.h" (or something)
43  /// file.
44  struct True {
45    static const bool value = true;
46  };
47
48  /// Basic type for defining "tags". A "NO" condition for enable_if.
49  struct False {
50    static const bool value = false;
51  };
52
53  template <typename T>
54  struct Wrap {
55    const T &value;
56    Wrap(const T &t) : value(t) {}
57  };
58
59  /**************** dummy class to avoid ambiguity ****************/
60
61  template<int T> struct dummy { dummy(int) {} };
62
63  /**************** enable_if from BOOST ****************/
64 
65  template <bool B, class T = void>
66  struct enable_if_c {
67    typedef T type;
68  };
69
70  template <class T>
71  struct enable_if_c<false, T> {};
72
73  template <class Cond, class T = void>
74  struct enable_if : public enable_if_c<Cond::value, T> {};
75
76  template <bool B, class T>
77  struct lazy_enable_if_c {
78    typedef typename T::type type;
79  };
80
81  template <class T>
82  struct lazy_enable_if_c<false, T> {};
83
84  template <class Cond, class T>
85  struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
86
87
88  template <bool B, class T = void>
89  struct disable_if_c {
90    typedef T type;
91  };
92
93  template <class T>
94  struct disable_if_c<true, T> {};
95
96  template <class Cond, class T = void>
97  struct disable_if : public disable_if_c<Cond::value, T> {};
98
99  template <bool B, class T>
100  struct lazy_disable_if_c {
101    typedef typename T::type type;
102  };
103
104  template <class T>
105  struct lazy_disable_if_c<true, T> {};
106
107  template <class Cond, class T>
108  struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
109
110} // namespace lemon
111
112#endif
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