183 lines
7.0 KiB
C++
183 lines
7.0 KiB
C++
// Functor implementations -*- C++ -*-
|
|
|
|
// Copyright (C) 2001-2020 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
|
|
|
|
// Suppress deprecated warning for this file.
|
|
#pragma GCC diagnostic push
|
|
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
|
|
|
|
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.
|
|
*
|
|
* These functions are deprecated in C++11 and can be replaced by
|
|
* @c std::bind (or @c std::tr1::bind) which is more powerful and flexible,
|
|
* supporting functions with any number of arguments. Uses of @c bind1st
|
|
* can be replaced by @c std::bind(f, x, std::placeholders::_1) and
|
|
* @c bind2nd by @c std::bind(f, std::placeholders::_1, x).
|
|
* @{
|
|
*/
|
|
/// 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
|
|
|
|
#pragma GCC diagnostic pop
|
|
|
|
#endif /* _BACKWARD_BINDERS_H */
|