| // Functor implementations -*- C++ -*- |
| |
| // Copyright (C) 2001-2022 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); } |
| } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind"); |
| |
| /// One of the @link binders binder functors@endlink. |
| template<typename _Operation, typename _Tp> |
| _GLIBCXX11_DEPRECATED_SUGGEST("std::bind") |
| 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); } |
| } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind"); |
| |
| /// One of the @link binders binder functors@endlink. |
| template<typename _Operation, typename _Tp> |
| _GLIBCXX11_DEPRECATED_SUGGEST("std::bind") |
| 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 */ |