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1 | // Functor implementations -*- C++ -*- |
2 | ||
2a60a9f6 | 3 | // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010 |
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4 | // Free Software Foundation, Inc. |
5 | // | |
6 | // This file is part of the GNU ISO C++ Library. This library is free | |
7 | // software; you can redistribute it and/or modify it under the | |
8 | // terms of the GNU General Public License as published by the | |
748086b7 | 9 | // Free Software Foundation; either version 3, or (at your option) |
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10 | // any later version. |
11 | ||
12 | // This library is distributed in the hope that it will be useful, | |
13 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | // GNU General Public License for more details. | |
16 | ||
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17 | // Under Section 7 of GPL version 3, you are granted additional |
18 | // permissions described in the GCC Runtime Library Exception, version | |
19 | // 3.1, as published by the Free Software Foundation. | |
40abbf1f | 20 | |
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21 | // You should have received a copy of the GNU General Public License and |
22 | // a copy of the GCC Runtime Library Exception along with this program; | |
23 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | // <http://www.gnu.org/licenses/>. | |
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25 | |
26 | /* | |
27 | * | |
28 | * Copyright (c) 1994 | |
29 | * Hewlett-Packard Company | |
30 | * | |
31 | * Permission to use, copy, modify, distribute and sell this software | |
32 | * and its documentation for any purpose is hereby granted without fee, | |
33 | * provided that the above copyright notice appear in all copies and | |
34 | * that both that copyright notice and this permission notice appear | |
35 | * in supporting documentation. Hewlett-Packard Company makes no | |
36 | * representations about the suitability of this software for any | |
37 | * purpose. It is provided "as is" without express or implied warranty. | |
38 | * | |
39 | * | |
40 | * Copyright (c) 1996-1998 | |
41 | * Silicon Graphics Computer Systems, Inc. | |
42 | * | |
43 | * Permission to use, copy, modify, distribute and sell this software | |
44 | * and its documentation for any purpose is hereby granted without fee, | |
45 | * provided that the above copyright notice appear in all copies and | |
46 | * that both that copyright notice and this permission notice appear | |
47 | * in supporting documentation. Silicon Graphics makes no | |
48 | * representations about the suitability of this software for any | |
49 | * purpose. It is provided "as is" without express or implied warranty. | |
50 | */ | |
51 | ||
52 | /** @file backward/binders.h | |
53 | * This is an internal header file, included by other library headers. | |
54 | * You should not attempt to use it directly. | |
55 | */ | |
56 | ||
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57 | #ifndef _BACKWARD_BINDERS_H |
58 | #define _BACKWARD_BINDERS_H 1 | |
40abbf1f | 59 | |
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60 | namespace std _GLIBCXX_VISIBILITY(default) |
61 | { | |
62 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
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63 | |
64 | // 20.3.6 binders | |
5b9daa7e | 65 | /** @defgroup binders Binder Classes |
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66 | * @ingroup functors |
67 | * | |
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68 | * Binders turn functions/functors with two arguments into functors |
69 | * with a single argument, storing an argument to be applied later. | |
70 | * For example, a variable @c B of type @c binder1st is constructed | |
71 | * from a functor @c f and an argument @c x. Later, B's @c | |
72 | * operator() is called with a single argument @c y. The return | |
73 | * value is the value of @c f(x,y). @c B can be @a called with | |
74 | * various arguments (y1, y2, ...) and will in turn call @c | |
75 | * f(x,y1), @c f(x,y2), ... | |
40abbf1f | 76 | * |
2a60a9f6 | 77 | * The function @c bind1st is provided to save some typing. It takes the |
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78 | * function and an argument as parameters, and returns an instance of |
79 | * @c binder1st. | |
80 | * | |
81 | * The type @c binder2nd and its creator function @c bind2nd do the same | |
82 | * thing, but the stored argument is passed as the second parameter instead | |
83 | * of the first, e.g., @c bind2nd(std::minus<float>,1.3) will create a | |
84 | * functor whose @c operator() accepts a floating-point number, subtracts | |
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85 | * 1.3 from it, and returns the result. (If @c bind1st had been used, |
86 | * the functor would perform <em>1.3 - x</em> instead. | |
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87 | * |
88 | * Creator-wrapper functions like @c bind1st are intended to be used in | |
2a60a9f6 | 89 | * calling algorithms. Their return values will be temporary objects. |
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90 | * (The goal is to not require you to type names like |
91 | * @c std::binder1st<std::plus<int>> for declaring a variable to hold the | |
92 | * return value from @c bind1st(std::plus<int>,5). | |
93 | * | |
94 | * These become more useful when combined with the composition functions. | |
95 | * | |
96 | * @{ | |
97 | */ | |
5b9daa7e | 98 | /// One of the @link binders binder functors@endlink. |
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99 | template<typename _Operation> |
100 | class binder1st | |
101 | : public unary_function<typename _Operation::second_argument_type, | |
102 | typename _Operation::result_type> | |
103 | { | |
104 | protected: | |
105 | _Operation op; | |
106 | typename _Operation::first_argument_type value; | |
107 | ||
108 | public: | |
109 | binder1st(const _Operation& __x, | |
110 | const typename _Operation::first_argument_type& __y) | |
111 | : op(__x), value(__y) { } | |
112 | ||
113 | typename _Operation::result_type | |
114 | operator()(const typename _Operation::second_argument_type& __x) const | |
115 | { return op(value, __x); } | |
116 | ||
117 | // _GLIBCXX_RESOLVE_LIB_DEFECTS | |
118 | // 109. Missing binders for non-const sequence elements | |
119 | typename _Operation::result_type | |
120 | operator()(typename _Operation::second_argument_type& __x) const | |
121 | { return op(value, __x); } | |
4dd9d9db | 122 | } _GLIBCXX_DEPRECATED_ATTR; |
40abbf1f | 123 | |
5b9daa7e | 124 | /// One of the @link binders binder functors@endlink. |
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125 | template<typename _Operation, typename _Tp> |
126 | inline binder1st<_Operation> | |
127 | bind1st(const _Operation& __fn, const _Tp& __x) | |
128 | { | |
129 | typedef typename _Operation::first_argument_type _Arg1_type; | |
130 | return binder1st<_Operation>(__fn, _Arg1_type(__x)); | |
131 | } | |
132 | ||
5b9daa7e | 133 | /// One of the @link binders binder functors@endlink. |
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134 | template<typename _Operation> |
135 | class binder2nd | |
136 | : public unary_function<typename _Operation::first_argument_type, | |
137 | typename _Operation::result_type> | |
138 | { | |
139 | protected: | |
140 | _Operation op; | |
141 | typename _Operation::second_argument_type value; | |
142 | ||
143 | public: | |
144 | binder2nd(const _Operation& __x, | |
145 | const typename _Operation::second_argument_type& __y) | |
146 | : op(__x), value(__y) { } | |
147 | ||
148 | typename _Operation::result_type | |
149 | operator()(const typename _Operation::first_argument_type& __x) const | |
150 | { return op(__x, value); } | |
151 | ||
152 | // _GLIBCXX_RESOLVE_LIB_DEFECTS | |
153 | // 109. Missing binders for non-const sequence elements | |
154 | typename _Operation::result_type | |
155 | operator()(typename _Operation::first_argument_type& __x) const | |
156 | { return op(__x, value); } | |
4dd9d9db | 157 | } _GLIBCXX_DEPRECATED_ATTR; |
40abbf1f | 158 | |
5b9daa7e | 159 | /// One of the @link binders binder functors@endlink. |
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160 | template<typename _Operation, typename _Tp> |
161 | inline binder2nd<_Operation> | |
162 | bind2nd(const _Operation& __fn, const _Tp& __x) | |
163 | { | |
164 | typedef typename _Operation::second_argument_type _Arg2_type; | |
165 | return binder2nd<_Operation>(__fn, _Arg2_type(__x)); | |
166 | } | |
167 | /** @} */ | |
168 | ||
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169 | _GLIBCXX_END_NAMESPACE_VERSION |
170 | } // namespace | |
40abbf1f | 171 | |
5ecfce5c | 172 | #endif /* _BACKWARD_BINDERS_H */ |