[7] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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[39] | 5 | * Copyright (C) 2003-2008 |
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[7] | 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | // This file contains a modified version of the enable_if library from BOOST. |
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| 20 | // See the appropriate copyright notice below. |
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| 21 | |
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| 22 | // Boost enable_if library |
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| 23 | |
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[117] | 24 | // Copyright 2003 (c) The Trustees of Indiana University. |
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[7] | 25 | |
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| 26 | // Use, modification, and distribution is subject to the Boost Software |
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| 27 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 28 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 29 | |
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[117] | 30 | // Authors: Jaakko Jarvi (jajarvi at osl.iu.edu) |
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[7] | 31 | // Jeremiah Willcock (jewillco at osl.iu.edu) |
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| 32 | // Andrew Lumsdaine (lums at osl.iu.edu) |
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| 33 | |
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| 34 | |
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| 35 | #ifndef LEMON_BITS_UTILITY_H |
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| 36 | #define LEMON_BITS_UTILITY_H |
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| 37 | |
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| 38 | ///\file |
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| 39 | ///\brief Miscellaneous basic utilities |
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| 40 | /// |
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| 41 | ///\todo Please rethink the organisation of the basic files like this. |
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| 42 | ///E.g. this file might be merged with invalid.h. |
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| 43 | |
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| 44 | |
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| 45 | namespace lemon |
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| 46 | { |
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| 47 | |
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| 48 | /// Basic type for defining "tags". A "YES" condition for \c enable_if. |
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| 49 | |
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| 50 | /// Basic type for defining "tags". A "YES" condition for \c enable_if. |
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| 51 | /// |
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| 52 | ///\sa False |
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| 53 | /// |
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| 54 | /// \todo This should go to a separate "basic_types.h" (or something) |
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| 55 | /// file. |
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| 56 | struct True { |
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| 57 | ///\e |
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| 58 | static const bool value = true; |
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| 59 | }; |
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| 60 | |
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| 61 | /// Basic type for defining "tags". A "NO" condition for \c enable_if. |
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| 62 | |
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| 63 | /// Basic type for defining "tags". A "NO" condition for \c enable_if. |
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| 64 | /// |
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| 65 | ///\sa True |
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| 66 | struct False { |
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| 67 | ///\e |
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| 68 | static const bool value = false; |
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| 69 | }; |
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| 70 | |
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| 71 | |
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| 72 | struct InvalidType { |
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| 73 | }; |
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| 74 | |
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| 75 | template <typename T> |
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| 76 | struct Wrap { |
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| 77 | const T &value; |
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| 78 | Wrap(const T &t) : value(t) {} |
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| 79 | }; |
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| 80 | |
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| 81 | /**************** dummy class to avoid ambiguity ****************/ |
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| 82 | |
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| 83 | template<int T> struct dummy { dummy(int) {} }; |
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| 84 | |
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| 85 | /**************** enable_if from BOOST ****************/ |
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| 86 | |
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| 87 | template <typename Type, typename T = void> |
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| 88 | struct exists { |
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| 89 | typedef T type; |
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| 90 | }; |
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| 91 | |
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| 92 | |
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| 93 | template <bool B, class T = void> |
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| 94 | struct enable_if_c { |
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| 95 | typedef T type; |
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| 96 | }; |
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| 97 | |
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| 98 | template <class T> |
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| 99 | struct enable_if_c<false, T> {}; |
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| 100 | |
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| 101 | template <class Cond, class T = void> |
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| 102 | struct enable_if : public enable_if_c<Cond::value, T> {}; |
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| 103 | |
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| 104 | template <bool B, class T> |
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| 105 | struct lazy_enable_if_c { |
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| 106 | typedef typename T::type type; |
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| 107 | }; |
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| 108 | |
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| 109 | template <class T> |
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| 110 | struct lazy_enable_if_c<false, T> {}; |
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| 111 | |
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| 112 | template <class Cond, class T> |
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| 113 | struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {}; |
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| 114 | |
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| 115 | |
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| 116 | template <bool B, class T = void> |
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| 117 | struct disable_if_c { |
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| 118 | typedef T type; |
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| 119 | }; |
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| 120 | |
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| 121 | template <class T> |
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| 122 | struct disable_if_c<true, T> {}; |
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| 123 | |
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| 124 | template <class Cond, class T = void> |
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| 125 | struct disable_if : public disable_if_c<Cond::value, T> {}; |
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| 126 | |
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| 127 | template <bool B, class T> |
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| 128 | struct lazy_disable_if_c { |
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| 129 | typedef typename T::type type; |
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| 130 | }; |
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| 131 | |
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| 132 | template <class T> |
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| 133 | struct lazy_disable_if_c<true, T> {}; |
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| 134 | |
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| 135 | template <class Cond, class T> |
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| 136 | struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {}; |
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| 137 | |
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| 138 | } // namespace lemon |
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| 139 | |
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| 140 | #endif |
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