[977] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * src/lemon/utility.h - Part of LEMON, a generic C++ optimization library |
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| 4 | * |
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| 5 | * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi |
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| 6 | * Kutatocsoport (Egervary Combinatorial Optimization Research Group, |
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| 7 | * 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 | * This file contains a modified version of the enable_if library from BOOST. |
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| 18 | * See the appropriate copyright notice below. |
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| 19 | */ |
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| 20 | |
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| 21 | // Boost enable_if library |
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| 22 | |
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| 23 | // Copyright 2003 © The Trustees of Indiana University. |
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| 24 | |
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| 25 | // Use, modification, and distribution is subject to the Boost Software |
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| 26 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 27 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 28 | |
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| 29 | // Authors: Jaakko Järvi (jajarvi at osl.iu.edu) |
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| 30 | // Jeremiah Willcock (jewillco at osl.iu.edu) |
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| 31 | // Andrew Lumsdaine (lums at osl.iu.edu) |
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| 32 | |
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| 33 | |
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| 34 | #ifndef LEMON_UTILITY_H |
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| 35 | #define LEMON_UTILITY_H |
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| 36 | |
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| 37 | namespace lemon |
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| 38 | { |
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| 39 | |
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| 40 | /// Basic type for defining "tags". A "YES" condidion for enable_if. |
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| 41 | |
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| 42 | /// \todo This should go to a separate "basic_types.h" (or something) |
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| 43 | /// file. |
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| 44 | struct True { |
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| 45 | static const bool value = true; |
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| 46 | }; |
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| 47 | |
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| 48 | /// Basic type for defining "tags". A "NO" condidion for enable_if. |
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| 49 | struct False { |
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| 50 | static const bool value = false; |
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| 51 | }; |
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| 52 | |
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| 53 | template <typename T> |
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| 54 | struct Wrap { |
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| 55 | const T &value; |
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| 56 | Wrap(const T &t) : value(t) {} |
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| 57 | }; |
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| 58 | |
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| 59 | |
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| 60 | |
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| 61 | /**************** enable_if from BOOST ****************/ |
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| 62 | |
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| 63 | template <bool B, class T = void> |
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| 64 | struct enable_if_c { |
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| 65 | typedef T type; |
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| 66 | }; |
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| 67 | |
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| 68 | template <class T> |
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| 69 | struct enable_if_c<false, T> {}; |
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| 70 | |
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| 71 | template <class Cond, class T = void> |
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| 72 | struct enable_if : public enable_if_c<Cond::value, T> {}; |
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| 73 | |
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| 74 | template <bool B, class T> |
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| 75 | struct lazy_enable_if_c { |
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| 76 | typedef typename T::type type; |
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| 77 | }; |
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| 78 | |
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| 79 | template <class T> |
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| 80 | struct lazy_enable_if_c<false, T> {}; |
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| 81 | |
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| 82 | template <class Cond, class T> |
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| 83 | struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {}; |
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| 84 | |
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| 85 | |
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| 86 | template <bool B, class T = void> |
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| 87 | struct disable_if_c { |
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| 88 | typedef T type; |
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| 89 | }; |
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| 90 | |
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| 91 | template <class T> |
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| 92 | struct disable_if_c<true, T> {}; |
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| 93 | |
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| 94 | template <class Cond, class T = void> |
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| 95 | struct disable_if : public disable_if_c<Cond::value, T> {}; |
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| 96 | |
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| 97 | template <bool B, class T> |
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| 98 | struct lazy_disable_if_c { |
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| 99 | typedef typename T::type type; |
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| 100 | }; |
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| 101 | |
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| 102 | template <class T> |
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| 103 | struct lazy_disable_if_c<true, T> {}; |
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| 104 | |
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| 105 | template <class Cond, class T> |
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| 106 | struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {}; |
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| 107 | |
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| 108 | } // namespace lemon |
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| 109 | |
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| 110 | #endif |
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