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// Functor implementations -*- C++ -*-

// Copyright (C) 2001-2015 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

// .

/*

 *

 * 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 bits/stl_function.h

 *  This is an internal header file, included by other library headers.

 *  Do not attempt to use it directly. @headername{functional}

 */

#ifndef _STL_FUNCTION_H

#define _STL_FUNCTION_H 1

#if __cplusplus > 201103L

#include 

#endif

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // 20.3.1 base classes

  /** @defgroup functors Function Objects

   * @ingroup utilities

   *

   *  Function objects, or @e functors, are objects with an @c operator()

   *  defined and accessible.  They can be passed as arguments to algorithm

   *  templates and used in place of a function pointer.  Not only is the

   *  resulting expressiveness of the library increased, but the generated

   *  code can be more efficient than what you might write by hand.  When we

   *  refer to @a functors, then, generally we include function pointers in

   *  the description as well.

   *

   *  Often, functors are only created as temporaries passed to algorithm

   *  calls, rather than being created as named variables.

   *

   *  Two examples taken from the standard itself follow.  To perform a

   *  by-element addition of two vectors @c a and @c b containing @c double,

   *  and put the result in @c a, use

   *  \code

   *  transform (a.begin(), a.end(), b.begin(), a.begin(), plus());

   *  \endcode

   *  To negate every element in @c a, use

   *  \code

   *  transform(a.begin(), a.end(), a.begin(), negate());

   *  \endcode

   *  The addition and negation functions will be inlined directly.

   *

   *  The standard functors are derived from structs named @c unary_function

   *  and @c binary_function.  These two classes contain nothing but typedefs,

   *  to aid in generic (template) programming.  If you write your own

   *  functors, you might consider doing the same.

   *

   *  @{

   */

  /**

   *  This is one of the @link functors functor base classes@endlink.

   */

  template

    struct unary_function

    {

      /// @c argument_type is the type of the argument

      typedef _Arg 	argument_type;

      /// @c result_type is the return type

      typedef _Result 	result_type;

    };

  /**

   *  This is one of the @link functors functor base classes@endlink.

   */

  template

    struct binary_function

    {

      /// @c first_argument_type is the type of the first argument

      typedef _Arg1 	first_argument_type;

      /// @c second_argument_type is the type of the second argument

      typedef _Arg2 	second_argument_type;

      /// @c result_type is the return type

      typedef _Result 	result_type;

    };

  /** @}  */

  // 20.3.2 arithmetic

  /** @defgroup arithmetic_functors Arithmetic Classes

   * @ingroup functors

   *

   *  Because basic math often needs to be done during an algorithm,

   *  the library provides functors for those operations.  See the

   *  documentation for @link functors the base classes@endlink

   *  for examples of their use.

   *

   *  @{

   */

#if __cplusplus > 201103L

  struct __is_transparent;  // undefined

  template

    struct plus;

  template

    struct minus;

  template

    struct multiplies;

  template

    struct divides;

  template

    struct modulus;

  template

    struct negate;

#endif

  /// One of the @link arithmetic_functors math functors@endlink.

  template

    struct plus : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x + __y; }

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template

    struct minus : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x - __y; }

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template

    struct multiplies : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x * __y; }

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template

    struct divides : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x / __y; }

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template

    struct modulus : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x % __y; }

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template

    struct negate : public unary_function<_Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x) const

      { return -__x; }

    };

#if __cplusplus > 201103L

#define __cpp_lib_transparent_operators 201210

//#define __cpp_lib_generic_associative_lookup 201304

  template<>

    struct plus

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) + std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) + std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) + std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template<>

    struct minus

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) - std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) - std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) - std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template<>

    struct multiplies

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) * std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) * std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) * std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template<>

    struct divides

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) / std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) / std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) / std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template<>

    struct modulus

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) % std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) % std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) % std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link arithmetic_functors math functors@endlink.

  template<>

    struct negate

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t) const

	noexcept(noexcept(-std::forward<_Tp>(__t)))

	-> decltype(-std::forward<_Tp>(__t))

	{ return -std::forward<_Tp>(__t); }

      typedef __is_transparent is_transparent;

    };

#endif

  /** @}  */

  // 20.3.3 comparisons

  /** @defgroup comparison_functors Comparison Classes

   * @ingroup functors

   *

   *  The library provides six wrapper functors for all the basic comparisons

   *  in C++, like @c <.

   *

   *  @{

   */

#if __cplusplus > 201103L

  template

    struct equal_to;

  template

    struct not_equal_to;

  template

    struct greater;

  template

    struct less;

  template

    struct greater_equal;

  template

    struct less_equal;

#endif

  /// One of the @link comparison_functors comparison functors@endlink.

  template

    struct equal_to : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x == __y; }

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template

    struct not_equal_to : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x != __y; }

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template

    struct greater : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x > __y; }

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template

    struct less : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x < __y; }

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template

    struct greater_equal : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x >= __y; }

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template

    struct less_equal : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x <= __y; }

    };

#if __cplusplus > 201103L

  /// One of the @link comparison_functors comparison functors@endlink.

  template<>

    struct equal_to

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) == std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) == std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) == std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template<>

    struct not_equal_to

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) != std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) != std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) != std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template<>

    struct greater

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) > std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) > std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template<>

    struct less

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) < std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) < std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) < std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template<>

    struct greater_equal

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) >= std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) >= std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) >= std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link comparison_functors comparison functors@endlink.

  template<>

    struct less_equal

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) <= std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) <= std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) <= std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

#endif

  /** @}  */

  // 20.3.4 logical operations

  /** @defgroup logical_functors Boolean Operations Classes

   * @ingroup functors

   *

   *  Here are wrapper functors for Boolean operations: @c &&, @c ||,

   *  and @c !.

   *

   *  @{

   */

#if __cplusplus > 201103L

  template

    struct logical_and;

  template

    struct logical_or;

  template

    struct logical_not;

#endif

  /// One of the @link logical_functors Boolean operations functors@endlink.

  template

    struct logical_and : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x && __y; }

    };

  /// One of the @link logical_functors Boolean operations functors@endlink.

  template

    struct logical_or : public binary_function<_Tp, _Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x || __y; }

    };

  /// One of the @link logical_functors Boolean operations functors@endlink.

  template

    struct logical_not : public unary_function<_Tp, bool>

    {

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const _Tp& __x) const

      { return !__x; }

    };

#if __cplusplus > 201103L

  /// One of the @link logical_functors Boolean operations functors@endlink.

  template<>

    struct logical_and

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) && std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) && std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) && std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link logical_functors Boolean operations functors@endlink.

  template<>

    struct logical_or

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) || std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) || std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) || std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  /// One of the @link logical_functors Boolean operations functors@endlink.

  template<>

    struct logical_not

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t) const

	noexcept(noexcept(!std::forward<_Tp>(__t)))

	-> decltype(!std::forward<_Tp>(__t))

	{ return !std::forward<_Tp>(__t); }

      typedef __is_transparent is_transparent;

    };

#endif

  /** @}  */

#if __cplusplus > 201103L

  template

    struct bit_and;

  template

    struct bit_or;

  template

    struct bit_xor;

  template

    struct bit_not;

#endif

  // _GLIBCXX_RESOLVE_LIB_DEFECTS

  // DR 660. Missing Bitwise Operations.

  template

    struct bit_and : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x & __y; }

    };

  template

    struct bit_or : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x | __y; }

    };

  template

    struct bit_xor : public binary_function<_Tp, _Tp, _Tp>

    {

      _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x, const _Tp& __y) const

      { return __x ^ __y; }

    };

  template

    struct bit_not : public unary_function<_Tp, _Tp>

    {

    _GLIBCXX14_CONSTEXPR

      _Tp

      operator()(const _Tp& __x) const

      { return ~__x; }

    };

#if __cplusplus > 201103L

  template <>

    struct bit_and

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) & std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) & std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) & std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  template <>

    struct bit_or

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) | std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) | std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) | std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  template <>

    struct bit_xor

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t, _Up&& __u) const

	noexcept(noexcept(std::forward<_Tp>(__t) ^ std::forward<_Up>(__u)))

	-> decltype(std::forward<_Tp>(__t) ^ std::forward<_Up>(__u))

	{ return std::forward<_Tp>(__t) ^ std::forward<_Up>(__u); }

      typedef __is_transparent is_transparent;

    };

  template <>

    struct bit_not

    {

      template 

	_GLIBCXX14_CONSTEXPR

	auto

	operator()(_Tp&& __t) const

	noexcept(noexcept(~std::forward<_Tp>(__t)))

	-> decltype(~std::forward<_Tp>(__t))

	{ return ~std::forward<_Tp>(__t); }

      typedef __is_transparent is_transparent;

    };

#endif

  // 20.3.5 negators

  /** @defgroup negators Negators

   * @ingroup functors

   *

   *  The functions @c not1 and @c not2 each take a predicate functor

   *  and return an instance of @c unary_negate or

   *  @c binary_negate, respectively.  These classes are functors whose

   *  @c operator() performs the stored predicate function and then returns

   *  the negation of the result.

   *

   *  For example, given a vector of integers and a trivial predicate,

   *  \code

   *  struct IntGreaterThanThree

   *    : public std::unary_function

   *  {

   *      bool operator() (int x) { return x > 3; }

   *  };

   *

   *  std::find_if (v.begin(), v.end(), not1(IntGreaterThanThree()));

   *  \endcode

   *  The call to @c find_if will locate the first index (i) of @c v for which

   *  !(v[i] > 3) is true.

   *

   *  The not1/unary_negate combination works on predicates taking a single

   *  argument.  The not2/binary_negate combination works on predicates which

   *  take two arguments.

   *

   *  @{

   */

  /// One of the @link negators negation functors@endlink.

  template

    class unary_negate

    : public unary_function

    {

    protected:

      _Predicate _M_pred;

    public:

      _GLIBCXX14_CONSTEXPR

      explicit

      unary_negate(const _Predicate& __x) : _M_pred(__x) { }

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const typename _Predicate::argument_type& __x) const

      { return !_M_pred(__x); }

    };

  /// One of the @link negators negation functors@endlink.

  template

    _GLIBCXX14_CONSTEXPR

    inline unary_negate<_Predicate>

    not1(const _Predicate& __pred)

    { return unary_negate<_Predicate>(__pred); }

  /// One of the @link negators negation functors@endlink.

  template

    class binary_negate

    : public binary_function

			     typename _Predicate::second_argument_type, bool>

    {

    protected:

      _Predicate _M_pred;

    public:

      _GLIBCXX14_CONSTEXPR

      explicit

      binary_negate(const _Predicate& __x) : _M_pred(__x) { }

      _GLIBCXX14_CONSTEXPR

      bool

      operator()(const typename _Predicate::first_argument_type& __x,

		 const typename _Predicate::second_argument_type& __y) const

      { return !_M_pred(__x, __y); }

    };

  /// One of the @link negators negation functors@endlink.

  template

    _GLIBCXX14_CONSTEXPR

    inline binary_negate<_Predicate>

    not2(const _Predicate& __pred)

    { return binary_negate<_Predicate>(__pred); }

  /** @}  */

  // 20.3.7 adaptors pointers functions

  /** @defgroup pointer_adaptors Adaptors for pointers to functions

   * @ingroup functors

   *

   *  The advantage of function objects over pointers to functions is that

   *  the objects in the standard library declare nested typedefs describing

   *  their argument and result types with uniform names (e.g., @c result_type

   *  from the base classes @c unary_function and @c binary_function).

   *  Sometimes those typedefs are required, not just optional.

   *

   *  Adaptors are provided to turn pointers to unary (single-argument) and

   *  binary (double-argument) functions into function objects.  The

   *  long-winded functor @c pointer_to_unary_function is constructed with a

   *  function pointer @c f, and its @c operator() called with argument @c x

   *  returns @c f(x).  The functor @c pointer_to_binary_function does the same

   *  thing, but with a double-argument @c f and @c operator().

   *

   *  The function @c ptr_fun takes a pointer-to-function @c f and constructs

   *  an instance of the appropriate functor.

   *

   *  @{

   */

  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.

  template

    class pointer_to_unary_function : public unary_function<_Arg, _Result>

    {

    protected:

      _Result (*_M_ptr)(_Arg);

    public:

      pointer_to_unary_function() { }

      explicit

      pointer_to_unary_function(_Result (*__x)(_Arg))

      : _M_ptr(__x) { }

      _Result

      operator()(_Arg __x) const

      { return _M_ptr(__x); }

    };

  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.

  template

    inline pointer_to_unary_function<_Arg, _Result>

    ptr_fun(_Result (*__x)(_Arg))

    { return pointer_to_unary_function<_Arg, _Result>(__x); }

  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.

  template

    class pointer_to_binary_function

    : public binary_function<_Arg1, _Arg2, _Result>

    {

    protected:

      _Result (*_M_ptr)(_Arg1, _Arg2);

    public:

      pointer_to_binary_function() { }

      explicit

      pointer_to_binary_function(_Result (*__x)(_Arg1, _Arg2))

      : _M_ptr(__x) { }

      _Result

      operator()(_Arg1 __x, _Arg2 __y) const

      { return _M_ptr(__x, __y); }

    };

  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.

  template

    inline pointer_to_binary_function<_Arg1, _Arg2, _Result>

    ptr_fun(_Result (*__x)(_Arg1, _Arg2))

    { return pointer_to_binary_function<_Arg1, _Arg2, _Result>(__x); }

  /** @}  */

  template

    struct _Identity

    : public unary_function<_Tp,_Tp>

    {

      _Tp&

      operator()(_Tp& __x) const

      { return __x; }

      const _Tp&

      operator()(const _Tp& __x) const

      { return __x; }

    };

  template

    struct _Select1st

    : public unary_function<_Pair, typename _Pair::first_type>

    {

      typename _Pair::first_type&

      operator()(_Pair& __x) const

      { return __x.first; }

      const typename _Pair::first_type&

      operator()(const _Pair& __x) const

      { return __x.first; }

#if __cplusplus >= 201103L

      template

        typename _Pair2::first_type&

        operator()(_Pair2& __x) const

        { return __x.first; }

      template

        const typename _Pair2::first_type&

        operator()(const _Pair2& __x) const

        { return __x.first; }

#endif

    };

  template

    struct _Select2nd

    : public unary_function<_Pair, typename _Pair::second_type>

    {

      typename _Pair::second_type&

      operator()(_Pair& __x) const

      { return __x.second; }

      const typename _Pair::second_type&

      operator()(const _Pair& __x) const

      { return __x.second; }

    };

  // 20.3.8 adaptors pointers members

  /** @defgroup memory_adaptors Adaptors for pointers to members

   * @ingroup functors

   *

   *  There are a total of 8 = 2^3 function objects in this family.

   *   (1) Member functions taking no arguments vs member functions taking

   *        one argument.

   *   (2) Call through pointer vs call through reference.

   *   (3) Const vs non-const member function.

   *

   *  All of this complexity is in the function objects themselves.  You can

   *   ignore it by using the helper function mem_fun and mem_fun_ref,

   *   which create whichever type of adaptor is appropriate.

   *

   *  @{

   */

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class mem_fun_t : public unary_function<_Tp*, _Ret>

    {

    public:

      explicit

      mem_fun_t(_Ret (_Tp::*__pf)())

      : _M_f(__pf) { }

      _Ret

      operator()(_Tp* __p) const

      { return (__p->*_M_f)(); }

    private:

      _Ret (_Tp::*_M_f)();

    };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class const_mem_fun_t : public unary_function

    {

    public:

      explicit

      const_mem_fun_t(_Ret (_Tp::*__pf)() const)

      : _M_f(__pf) { }

      _Ret

      operator()(const _Tp* __p) const

      { return (__p->*_M_f)(); }

    private:

      _Ret (_Tp::*_M_f)() const;

    };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class mem_fun_ref_t : public unary_function<_Tp, _Ret>

    {

    public:

      explicit

      mem_fun_ref_t(_Ret (_Tp::*__pf)())

      : _M_f(__pf) { }

      _Ret

      operator()(_Tp& __r) const

      { return (__r.*_M_f)(); }

    private:

      _Ret (_Tp::*_M_f)();

  };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class const_mem_fun_ref_t : public unary_function<_Tp, _Ret>

    {

    public:

      explicit

      const_mem_fun_ref_t(_Ret (_Tp::*__pf)() const)

      : _M_f(__pf) { }

      _Ret

      operator()(const _Tp& __r) const

      { return (__r.*_M_f)(); }

    private:

      _Ret (_Tp::*_M_f)() const;

    };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class mem_fun1_t : public binary_function<_Tp*, _Arg, _Ret>

    {

    public:

      explicit

      mem_fun1_t(_Ret (_Tp::*__pf)(_Arg))

      : _M_f(__pf) { }

      _Ret

      operator()(_Tp* __p, _Arg __x) const

      { return (__p->*_M_f)(__x); }

    private:

      _Ret (_Tp::*_M_f)(_Arg);

    };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class const_mem_fun1_t : public binary_function

    {

    public:

      explicit

      const_mem_fun1_t(_Ret (_Tp::*__pf)(_Arg) const)

      : _M_f(__pf) { }

      _Ret

      operator()(const _Tp* __p, _Arg __x) const

      { return (__p->*_M_f)(__x); }

    private:

      _Ret (_Tp::*_M_f)(_Arg) const;

    };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class mem_fun1_ref_t : public binary_function<_Tp, _Arg, _Ret>

    {

    public:

      explicit

      mem_fun1_ref_t(_Ret (_Tp::*__pf)(_Arg))

      : _M_f(__pf) { }

      _Ret

      operator()(_Tp& __r, _Arg __x) const

      { return (__r.*_M_f)(__x); }

    private:

      _Ret (_Tp::*_M_f)(_Arg);

    };

  /// One of the @link memory_adaptors adaptors for member

  /// pointers@endlink.

  template

    class const_mem_fun1_ref_t : public binary_function<_Tp, _Arg, _Ret>

    {

    public:

      explicit

      const_mem_fun1_ref_t(_Ret (_Tp::*__pf)(_Arg) const)

      : _M_f(__pf) { }

      _Ret

      operator()(const _Tp& __r, _Arg __x) const

      { return (__r.*_M_f)(__x); }

    private:

      _Ret (_Tp::*_M_f)(_Arg) const;

    };

  // Mem_fun adaptor helper functions.  There are only two:

  // mem_fun and mem_fun_ref.

  template

    inline mem_fun_t<_Ret, _Tp>

    mem_fun(_Ret (_Tp::*__f)())

    { return mem_fun_t<_Ret, _Tp>(__f); }

  template

    inline const_mem_fun_t<_Ret, _Tp>

    mem_fun(_Ret (_Tp::*__f)() const)

    { return const_mem_fun_t<_Ret, _Tp>(__f); }

  template

    inline mem_fun_ref_t<_Ret, _Tp>

    mem_fun_ref(_Ret (_Tp::*__f)())

    { return mem_fun_ref_t<_Ret, _Tp>(__f); }

  template

    inline const_mem_fun_ref_t<_Ret, _Tp>

    mem_fun_ref(_Ret (_Tp::*__f)() const)

    { return const_mem_fun_ref_t<_Ret, _Tp>(__f); }

  template

    inline mem_fun1_t<_Ret, _Tp, _Arg>

    mem_fun(_Ret (_Tp::*__f)(_Arg))

    { return mem_fun1_t<_Ret, _Tp, _Arg>(__f); }

  template

    inline const_mem_fun1_t<_Ret, _Tp, _Arg>

    mem_fun(_Ret (_Tp::*__f)(_Arg) const)

    { return const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); }

  template

    inline mem_fun1_ref_t<_Ret, _Tp, _Arg>