COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/utility.h @ 1852:ffa7c6e96330

Last change on this file since 1852:ffa7c6e96330 was 1705:3f63d9db307b, checked in by Balazs Dezso, 14 years ago

Removing smart references

File size: 3.6 KB
Line 
1/* -*- C++ -*-
2 * lemon/utility.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi
5 * Kutatocsoport (Egervary Research Group on Combinatorial Optimization,
6 * EGRES).
7 *
8 * Permission to use, modify and distribute this software is granted
9 * provided that this copyright notice appears in all copies. For
10 * precise terms see the accompanying LICENSE file.
11 *
12 * This software is provided "AS IS" with no warranty of any kind,
13 * express or implied, and with no claim as to its suitability for any
14 * purpose.
15 *
16 * This file contains a modified version of the enable_if library from BOOST.
17 * See the appropriate copyright notice below.
18 */
19
20// Boost enable_if library
21
22// Copyright 2003 © The Trustees of Indiana University.
23
24// Use, modification, and distribution is subject to the Boost Software
25// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
26// http://www.boost.org/LICENSE_1_0.txt)
27
28//    Authors: Jaakko Järvi (jajarvi at osl.iu.edu)
29//             Jeremiah Willcock (jewillco at osl.iu.edu)
30//             Andrew Lumsdaine (lums at osl.iu.edu)
31
32
33#ifndef LEMON_UTILITY_H
34#define LEMON_UTILITY_H
35
36///\file
37///\brief Miscellaneous basic utilities
38///
39///\todo Please rethink the organisation of the basic files like this.
40///E.g. this file might be merged with invalid.h.
41
42
43namespace lemon
44{
45
46  /// Basic type for defining "tags". A "YES" condition for \c enable_if.
47
48  /// Basic type for defining "tags". A "YES" condition for \c enable_if.
49  ///
50  ///\sa False
51  ///
52  /// \todo This should go to a separate "basic_types.h" (or something)
53  /// file.
54  struct True {
55    ///\e
56    static const bool value = true;
57  };
58
59  /// Basic type for defining "tags". A "NO" condition for \c enable_if.
60
61  /// Basic type for defining "tags". A "NO" condition for \c enable_if.
62  ///
63  ///\sa True
64  struct False {
65    ///\e
66    static const bool value = false;
67  };
68
69  template <bool left, bool right>
70  struct _CompileTimeAnd {
71    static const bool value = false;
72  };
73 
74  template <>
75  struct _CompileTimeAnd<true, true> {
76    static const bool value = true;
77  };
78
79  template <typename Left, typename Right>
80  struct CompileTimeAnd {
81    static const bool value =
82    _CompileTimeAnd<Left::value, Right::value>::value;
83  };
84
85  template <typename T>
86  struct Wrap {
87    const T &value;
88    Wrap(const T &t) : value(t) {}
89  };
90
91  /**************** dummy class to avoid ambiguity ****************/
92
93  template<int T> struct dummy { dummy(int) {} };
94
95  /**************** enable_if from BOOST ****************/
96 
97  template <bool B, class T = void>
98  struct enable_if_c {
99    typedef T type;
100  };
101
102  template <class T>
103  struct enable_if_c<false, T> {};
104
105  template <class Cond, class T = void>
106  struct enable_if : public enable_if_c<Cond::value, T> {};
107
108  template <bool B, class T>
109  struct lazy_enable_if_c {
110    typedef typename T::type type;
111  };
112
113  template <class T>
114  struct lazy_enable_if_c<false, T> {};
115
116  template <class Cond, class T>
117  struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
118
119
120  template <bool B, class T = void>
121  struct disable_if_c {
122    typedef T type;
123  };
124
125  template <class T>
126  struct disable_if_c<true, T> {};
127
128  template <class Cond, class T = void>
129  struct disable_if : public disable_if_c<Cond::value, T> {};
130
131  template <bool B, class T>
132  struct lazy_disable_if_c {
133    typedef typename T::type type;
134  };
135
136  template <class T>
137  struct lazy_disable_if_c<true, T> {};
138
139  template <class Cond, class T>
140  struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
141
142} // namespace lemon
143
144#endif
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