COIN-OR::LEMON - Graph Library

source: lemon-1.2/lemon/bits/enable_if.h @ 591:493533ead9df

Last change on this file since 591:493533ead9df was 440:88ed40ad0d4f, checked in by Alpar Juttner <alpar@…>, 11 years ago

Happy New Year again

  • update the copyright headers + run the source unifier
File size: 3.1 KB
Line 
1/* -*- mode: C++; indent-tabs-mode: nil; -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library.
4 *
5 * Copyright (C) 2003-2009
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, 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 */
18
19// This file contains a modified version of the enable_if library from BOOST.
20// See the appropriate copyright notice below.
21
22// Boost enable_if library
23
24// Copyright 2003 (c) The Trustees of Indiana University.
25
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)
29
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)
33
34
35#ifndef LEMON_BITS_ENABLE_IF_H
36#define LEMON_BITS_ENABLE_IF_H
37
38//\file
39//\brief Miscellaneous basic utilities
40
41namespace lemon
42{
43
44  // Basic type for defining "tags". A "YES" condition for \c enable_if.
45
46  // Basic type for defining "tags". A "YES" condition for \c enable_if.
47  //
48  //\sa False
49  struct True {
50    //\e
51    static const bool value = true;
52  };
53
54  // Basic type for defining "tags". A "NO" condition for \c enable_if.
55
56  // Basic type for defining "tags". A "NO" condition for \c enable_if.
57  //
58  //\sa True
59  struct False {
60    //\e
61    static const bool value = false;
62  };
63
64
65
66  template <typename T>
67  struct Wrap {
68    const T &value;
69    Wrap(const T &t) : value(t) {}
70  };
71
72  /**************** dummy class to avoid ambiguity ****************/
73
74  template<int T> struct dummy { dummy(int) {} };
75
76  /**************** enable_if from BOOST ****************/
77
78  template <typename Type, typename T = void>
79  struct exists {
80    typedef T type;
81  };
82
83
84  template <bool B, class T = void>
85  struct enable_if_c {
86    typedef T type;
87  };
88
89  template <class T>
90  struct enable_if_c<false, T> {};
91
92  template <class Cond, class T = void>
93  struct enable_if : public enable_if_c<Cond::value, T> {};
94
95  template <bool B, class T>
96  struct lazy_enable_if_c {
97    typedef typename T::type type;
98  };
99
100  template <class T>
101  struct lazy_enable_if_c<false, T> {};
102
103  template <class Cond, class T>
104  struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
105
106
107  template <bool B, class T = void>
108  struct disable_if_c {
109    typedef T type;
110  };
111
112  template <class T>
113  struct disable_if_c<true, T> {};
114
115  template <class Cond, class T = void>
116  struct disable_if : public disable_if_c<Cond::value, T> {};
117
118  template <bool B, class T>
119  struct lazy_disable_if_c {
120    typedef typename T::type type;
121  };
122
123  template <class T>
124  struct lazy_disable_if_c<true, T> {};
125
126  template <class Cond, class T>
127  struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
128
129} // namespace lemon
130
131#endif
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