1    	// Functor implementations -*- C++ -*-
2    	
3    	// Copyright (C) 2001-2017 Free Software Foundation, Inc.
4    	//
5    	// This file is part of the GNU ISO C++ Library.  This library is free
6    	// software; you can redistribute it and/or modify it under the
7    	// terms of the GNU General Public License as published by the
8    	// Free Software Foundation; either version 3, or (at your option)
9    	// any later version.
10   	
11   	// This library is distributed in the hope that it will be useful,
12   	// but WITHOUT ANY WARRANTY; without even the implied warranty of
13   	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   	// GNU General Public License for more details.
15   	
16   	// Under Section 7 of GPL version 3, you are granted additional
17   	// permissions described in the GCC Runtime Library Exception, version
18   	// 3.1, as published by the Free Software Foundation.
19   	
20   	// You should have received a copy of the GNU General Public License and
21   	// a copy of the GCC Runtime Library Exception along with this program;
22   	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23   	// <http://www.gnu.org/licenses/>.
24   	
25   	/*
26   	 *
27   	 * Copyright (c) 1994
28   	 * Hewlett-Packard Company
29   	 *
30   	 * Permission to use, copy, modify, distribute and sell this software
31   	 * and its documentation for any purpose is hereby granted without fee,
32   	 * provided that the above copyright notice appear in all copies and
33   	 * that both that copyright notice and this permission notice appear
34   	 * in supporting documentation.  Hewlett-Packard Company makes no
35   	 * representations about the suitability of this software for any
36   	 * purpose.  It is provided "as is" without express or implied warranty.
37   	 *
38   	 *
39   	 * Copyright (c) 1996-1998
40   	 * Silicon Graphics Computer Systems, Inc.
41   	 *
42   	 * Permission to use, copy, modify, distribute and sell this software
43   	 * and its documentation for any purpose is hereby granted without fee,
44   	 * provided that the above copyright notice appear in all copies and
45   	 * that both that copyright notice and this permission notice appear
46   	 * in supporting documentation.  Silicon Graphics makes no
47   	 * representations about the suitability of this software for any
48   	 * purpose.  It is provided "as is" without express or implied warranty.
49   	 */
50   	
51   	/** @file backward/binders.h
52   	 *  This is an internal header file, included by other library headers.
53   	 *  Do not attempt to use it directly. @headername{functional}
54   	 */
55   	
56   	#ifndef _BACKWARD_BINDERS_H
57   	#define _BACKWARD_BINDERS_H 1
58   	
59   	// Suppress deprecated warning for this file.
60   	#pragma GCC diagnostic push
61   	#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
62   	
63   	namespace std _GLIBCXX_VISIBILITY(default)
64   	{
65   	_GLIBCXX_BEGIN_NAMESPACE_VERSION
66   	
67   	  // 20.3.6 binders
68   	  /** @defgroup binders Binder Classes
69   	   * @ingroup functors
70   	   *
71   	   *  Binders turn functions/functors with two arguments into functors
72   	   *  with a single argument, storing an argument to be applied later.
73   	   *  For example, a variable @c B of type @c binder1st is constructed
74   	   *  from a functor @c f and an argument @c x. Later, B's @c
75   	   *  operator() is called with a single argument @c y. The return
76   	   *  value is the value of @c f(x,y). @c B can be @a called with
77   	   *  various arguments (y1, y2, ...) and will in turn call @c
78   	   *  f(x,y1), @c f(x,y2), ...
79   	   *
80   	   *  The function @c bind1st is provided to save some typing. It takes the
81   	   *  function and an argument as parameters, and returns an instance of
82   	   *  @c binder1st.
83   	   *
84   	   *  The type @c binder2nd and its creator function @c bind2nd do the same
85   	   *  thing, but the stored argument is passed as the second parameter instead
86   	   *  of the first, e.g., @c bind2nd(std::minus<float>(),1.3) will create a
87   	   *  functor whose @c operator() accepts a floating-point number, subtracts
88   	   *  1.3 from it, and returns the result. (If @c bind1st had been used,
89   	   *  the functor would perform <em>1.3 - x</em> instead.
90   	   *
91   	   *  Creator-wrapper functions like @c bind1st are intended to be used in
92   	   *  calling algorithms. Their return values will be temporary objects.
93   	   *  (The goal is to not require you to type names like
94   	   *  @c std::binder1st<std::plus<int>> for declaring a variable to hold the
95   	   *  return value from @c bind1st(std::plus<int>(),5).
96   	   *
97   	   *  These become more useful when combined with the composition functions.
98   	   *
99   	   *  These functions are deprecated in C++11 and can be replaced by
100  	   *  @c std::bind (or @c std::tr1::bind) which is more powerful and flexible,
101  	   *  supporting functions with any number of arguments.  Uses of @c bind1st
102  	   *  can be replaced by @c std::bind(f, x, std::placeholders::_1) and
103  	   *  @c bind2nd by @c std::bind(f, std::placeholders::_1, x).
104  	   *  @{
105  	   */
106  	  /// One of the @link binders binder functors@endlink.
107  	  template<typename _Operation>
108  	    class binder1st
109  	    : public unary_function<typename _Operation::second_argument_type,
110  				    typename _Operation::result_type>
111  	    {
112  	    protected:
113  	      _Operation op;
114  	      typename _Operation::first_argument_type value;
115  	
116  	    public:
117  	      binder1st(const _Operation& __x,
118  			const typename _Operation::first_argument_type& __y)
119  	      : op(__x), value(__y) { }
120  	
121  	      typename _Operation::result_type
122  	      operator()(const typename _Operation::second_argument_type& __x) const
123  	      { return op(value, __x); }
124  	
125  	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
126  	      // 109.  Missing binders for non-const sequence elements
127  	      typename _Operation::result_type
128  	      operator()(typename _Operation::second_argument_type& __x) const
129  	      { return op(value, __x); }
130  	    } _GLIBCXX_DEPRECATED;
131  	
132  	  /// One of the @link binders binder functors@endlink.
133  	  template<typename _Operation, typename _Tp>
134  	    inline binder1st<_Operation>
135  	    bind1st(const _Operation& __fn, const _Tp& __x)
136  	    {
137  	      typedef typename _Operation::first_argument_type _Arg1_type;
138  	      return binder1st<_Operation>(__fn, _Arg1_type(__x));
139  	    }
140  	
141  	  /// One of the @link binders binder functors@endlink.
142  	  template<typename _Operation>
143  	    class binder2nd
144  	    : public unary_function<typename _Operation::first_argument_type,
145  				    typename _Operation::result_type>
146  	    {
147  	    protected:
148  	      _Operation op;
149  	      typename _Operation::second_argument_type value;
150  	
151  	    public:
152  	      binder2nd(const _Operation& __x,
153  			const typename _Operation::second_argument_type& __y)
154  	      : op(__x), value(__y) { }
155  	
156  	      typename _Operation::result_type
157  	      operator()(const typename _Operation::first_argument_type& __x) const
158  	      { return op(__x, value); }
159  	
160  	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
161  	      // 109.  Missing binders for non-const sequence elements
162  	      typename _Operation::result_type
163  	      operator()(typename _Operation::first_argument_type& __x) const
164  	      { return op(__x, value); }
165  	    } _GLIBCXX_DEPRECATED;
166  	
167  	  /// One of the @link binders binder functors@endlink.
168  	  template<typename _Operation, typename _Tp>
169  	    inline binder2nd<_Operation>
170  	    bind2nd(const _Operation& __fn, const _Tp& __x)
171  	    {
172  	      typedef typename _Operation::second_argument_type _Arg2_type;
173  	      return binder2nd<_Operation>(__fn, _Arg2_type(__x));
174  	    } 
175  	  /** @}  */
176  	
177  	_GLIBCXX_END_NAMESPACE_VERSION
178  	} // namespace
179  	
180  	#pragma GCC diagnostic pop
181  	
182  	#endif /* _BACKWARD_BINDERS_H */
183