1 | /* -*- C++ -*- |
---|
2 | * |
---|
3 | * This file is a part of LEMON, a generic C++ optimization library |
---|
4 | * |
---|
5 | * Copyright (C) 2003-2006 |
---|
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 © 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 Järvi (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_UTILITY_H |
---|
36 | #define LEMON_UTILITY_H |
---|
37 | |
---|
38 | ///\file |
---|
39 | ///\brief Miscellaneous basic utilities |
---|
40 | /// |
---|
41 | ///\todo Please rethink the organisation of the basic files like this. |
---|
42 | ///E.g. this file might be merged with invalid.h. |
---|
43 | |
---|
44 | |
---|
45 | namespace lemon |
---|
46 | { |
---|
47 | |
---|
48 | /// Basic type for defining "tags". A "YES" condition for \c enable_if. |
---|
49 | |
---|
50 | /// Basic type for defining "tags". A "YES" condition for \c enable_if. |
---|
51 | /// |
---|
52 | ///\sa False |
---|
53 | /// |
---|
54 | /// \todo This should go to a separate "basic_types.h" (or something) |
---|
55 | /// file. |
---|
56 | struct True { |
---|
57 | ///\e |
---|
58 | static const bool value = true; |
---|
59 | }; |
---|
60 | |
---|
61 | /// Basic type for defining "tags". A "NO" condition for \c enable_if. |
---|
62 | |
---|
63 | /// Basic type for defining "tags". A "NO" condition for \c enable_if. |
---|
64 | /// |
---|
65 | ///\sa True |
---|
66 | struct False { |
---|
67 | ///\e |
---|
68 | static const bool value = false; |
---|
69 | }; |
---|
70 | |
---|
71 | template <bool left, bool right> |
---|
72 | struct _CompileTimeAnd { |
---|
73 | static const bool value = false; |
---|
74 | }; |
---|
75 | |
---|
76 | template <> |
---|
77 | struct _CompileTimeAnd<true, true> { |
---|
78 | static const bool value = true; |
---|
79 | }; |
---|
80 | |
---|
81 | template <typename Left, typename Right> |
---|
82 | struct CompileTimeAnd { |
---|
83 | static const bool value = |
---|
84 | _CompileTimeAnd<Left::value, Right::value>::value; |
---|
85 | }; |
---|
86 | |
---|
87 | template <typename T> |
---|
88 | struct Wrap { |
---|
89 | const T &value; |
---|
90 | Wrap(const T &t) : value(t) {} |
---|
91 | }; |
---|
92 | |
---|
93 | /**************** dummy class to avoid ambiguity ****************/ |
---|
94 | |
---|
95 | template<int T> struct dummy { dummy(int) {} }; |
---|
96 | |
---|
97 | /**************** enable_if from BOOST ****************/ |
---|
98 | |
---|
99 | template <bool B, class T = void> |
---|
100 | struct enable_if_c { |
---|
101 | typedef T type; |
---|
102 | }; |
---|
103 | |
---|
104 | template <class T> |
---|
105 | struct enable_if_c<false, T> {}; |
---|
106 | |
---|
107 | template <class Cond, class T = void> |
---|
108 | struct enable_if : public enable_if_c<Cond::value, T> {}; |
---|
109 | |
---|
110 | template <bool B, class T> |
---|
111 | struct lazy_enable_if_c { |
---|
112 | typedef typename T::type type; |
---|
113 | }; |
---|
114 | |
---|
115 | template <class T> |
---|
116 | struct lazy_enable_if_c<false, T> {}; |
---|
117 | |
---|
118 | template <class Cond, class T> |
---|
119 | struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {}; |
---|
120 | |
---|
121 | |
---|
122 | template <bool B, class T = void> |
---|
123 | struct disable_if_c { |
---|
124 | typedef T type; |
---|
125 | }; |
---|
126 | |
---|
127 | template <class T> |
---|
128 | struct disable_if_c<true, T> {}; |
---|
129 | |
---|
130 | template <class Cond, class T = void> |
---|
131 | struct disable_if : public disable_if_c<Cond::value, T> {}; |
---|
132 | |
---|
133 | template <bool B, class T> |
---|
134 | struct lazy_disable_if_c { |
---|
135 | typedef typename T::type type; |
---|
136 | }; |
---|
137 | |
---|
138 | template <class T> |
---|
139 | struct lazy_disable_if_c<true, T> {}; |
---|
140 | |
---|
141 | template <class Cond, class T> |
---|
142 | struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {}; |
---|
143 | |
---|
144 | } // namespace lemon |
---|
145 | |
---|
146 | #endif |
---|