summaryrefslogtreecommitdiff
path: root/libstdc++-v3/include/backward/binders.h
blob: f98b56aaedebd4045718d13693c901b9d66844d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
// Functor implementations -*- C++ -*-

// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2011
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996-1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file backward/binders.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{functional}
 */

#ifndef _BACKWARD_BINDERS_H
#define _BACKWARD_BINDERS_H 1

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // 20.3.6 binders
  /** @defgroup binders Binder Classes
   * @ingroup functors
   *
   *  Binders turn functions/functors with two arguments into functors
   *  with a single argument, storing an argument to be applied later.
   *  For example, a variable @c B of type @c binder1st is constructed
   *  from a functor @c f and an argument @c x. Later, B's @c
   *  operator() is called with a single argument @c y. The return
   *  value is the value of @c f(x,y). @c B can be @a called with
   *  various arguments (y1, y2, ...) and will in turn call @c
   *  f(x,y1), @c f(x,y2), ...
   *
   *  The function @c bind1st is provided to save some typing. It takes the
   *  function and an argument as parameters, and returns an instance of
   *  @c binder1st.
   *
   *  The type @c binder2nd and its creator function @c bind2nd do the same
   *  thing, but the stored argument is passed as the second parameter instead
   *  of the first, e.g., @c bind2nd(std::minus<float>,1.3) will create a
   *  functor whose @c operator() accepts a floating-point number, subtracts
   *  1.3 from it, and returns the result. (If @c bind1st had been used,
   *  the functor would perform <em>1.3 - x</em> instead.
   *
   *  Creator-wrapper functions like @c bind1st are intended to be used in
   *  calling algorithms. Their return values will be temporary objects.
   *  (The goal is to not require you to type names like
   *  @c std::binder1st<std::plus<int>> for declaring a variable to hold the
   *  return value from @c bind1st(std::plus<int>,5).
   *
   *  These become more useful when combined with the composition functions.
   *
   *  @{
   */
  /// One of the @link binders binder functors@endlink.
  template<typename _Operation>
    class binder1st
    : public unary_function<typename _Operation::second_argument_type,
			    typename _Operation::result_type>
    {
    protected:
      _Operation op;
      typename _Operation::first_argument_type value;

    public:
      binder1st(const _Operation& __x,
		const typename _Operation::first_argument_type& __y)
      : op(__x), value(__y) { }

      typename _Operation::result_type
      operator()(const typename _Operation::second_argument_type& __x) const
      { return op(value, __x); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 109.  Missing binders for non-const sequence elements
      typename _Operation::result_type
      operator()(typename _Operation::second_argument_type& __x) const
      { return op(value, __x); }
    } _GLIBCXX_DEPRECATED;

  /// One of the @link binders binder functors@endlink.
  template<typename _Operation, typename _Tp>
    inline binder1st<_Operation>
    bind1st(const _Operation& __fn, const _Tp& __x)
    {
      typedef typename _Operation::first_argument_type _Arg1_type;
      return binder1st<_Operation>(__fn, _Arg1_type(__x));
    }

  /// One of the @link binders binder functors@endlink.
  template<typename _Operation>
    class binder2nd
    : public unary_function<typename _Operation::first_argument_type,
			    typename _Operation::result_type>
    {
    protected:
      _Operation op;
      typename _Operation::second_argument_type value;

    public:
      binder2nd(const _Operation& __x,
		const typename _Operation::second_argument_type& __y)
      : op(__x), value(__y) { }

      typename _Operation::result_type
      operator()(const typename _Operation::first_argument_type& __x) const
      { return op(__x, value); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 109.  Missing binders for non-const sequence elements
      typename _Operation::result_type
      operator()(typename _Operation::first_argument_type& __x) const
      { return op(__x, value); }
    } _GLIBCXX_DEPRECATED;

  /// One of the @link binders binder functors@endlink.
  template<typename _Operation, typename _Tp>
    inline binder2nd<_Operation>
    bind2nd(const _Operation& __fn, const _Tp& __x)
    {
      typedef typename _Operation::second_argument_type _Arg2_type;
      return binder2nd<_Operation>(__fn, _Arg2_type(__x));
    } 
  /** @}  */

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* _BACKWARD_BINDERS_H */