dwarf2out.c (ranges_table): Change into vec<dw_ranges, va_gc> *.

[thirdparty/gcc.git] / libstdc++-v3 / include / std / functional

// <functional> -*- C++ -*-

// Copyright (C) 2001-2016 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) 1997
 * 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 include/functional
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_FUNCTIONAL
#define _GLIBCXX_FUNCTIONAL 1

#pragma GCC system_header

#include <bits/c++config.h>
#include <bits/stl_function.h>

#if __cplusplus >= 201103L

#include <typeinfo>
#include <new>
#include <tuple>
#include <type_traits>
#include <bits/functexcept.h>
#include <bits/functional_hash.h>
#include <bits/invoke.h>

#if __cplusplus > 201402L
#include <unordered_map>
#include <vector>
#include <array>
#include <utility>
#include <bits/stl_algo.h>
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template<typename _MemberPointer>
    class _Mem_fn;
  template<typename _Tp, typename _Class>
    _Mem_fn<_Tp _Class::*>
    mem_fn(_Tp _Class::*) noexcept;

  /// If we have found a result_type, extract it.
  template<typename _Functor, typename = __void_t<>>
    struct _Maybe_get_result_type
    { };

  template<typename _Functor>
    struct _Maybe_get_result_type<_Functor,
                                  __void_t<typename _Functor::result_type>>
    { typedef typename _Functor::result_type result_type; };

  /**
   *  Base class for any function object that has a weak result type, as
   *  defined in 20.8.2 [func.require] of C++11.
  */
  template<typename _Functor>
    struct _Weak_result_type_impl
    : _Maybe_get_result_type<_Functor>
    { };

  /// Retrieve the result type for a function type.
  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...) const>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......) const>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...) volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......) volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...) const volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......) const volatile>
    { typedef _Res result_type; };

  /// Retrieve the result type for a function reference.
  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(&)(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(&)(_ArgTypes......)>
    { typedef _Res result_type; };

  /// Retrieve the result type for a function pointer.
  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(*)(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(*)(_ArgTypes......)>
    { typedef _Res result_type; };

  /// Retrieve result type for a member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)>
    { typedef _Res result_type; };

  /// Retrieve result type for a const member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) const>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) const>
    { typedef _Res result_type; };

  /// Retrieve result type for a volatile member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) volatile>
    { typedef _Res result_type; };

  /// Retrieve result type for a const volatile member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)
                                  const volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)
                                  const volatile>
    { typedef _Res result_type; };

  /**
   *  Strip top-level cv-qualifiers from the function object and let
   *  _Weak_result_type_impl perform the real work.
  */
  template<typename _Functor>
    struct _Weak_result_type
    : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
    { };

#if __cplusplus > 201402L
# define __cpp_lib_invoke 201411

  /// Invoke a callable object.
  template<typename _Callable, typename... _Args>
    inline result_of_t<_Callable&&(_Args&&...)>
    invoke(_Callable&& __fn, _Args&&... __args)
    noexcept(is_nothrow_callable_v<_Callable&&(_Args&&...)>)
    {
      return std::__invoke(std::forward<_Callable>(__fn),
                           std::forward<_Args>(__args)...);
    }
#endif

  // Detect nested argument_type.
  template<typename _Tp, typename = __void_t<>>
    struct _Refwrap_base_arg1
    { };

  // Nested argument_type.
  template<typename _Tp>
    struct _Refwrap_base_arg1<_Tp,
                              __void_t<typename _Tp::argument_type>>
    {
      typedef typename _Tp::argument_type argument_type;
    };

  // Detect nested first_argument_type and second_argument_type.
  template<typename _Tp, typename = __void_t<>>
    struct _Refwrap_base_arg2
    { };

  // Nested first_argument_type and second_argument_type.
  template<typename _Tp>
    struct _Refwrap_base_arg2<_Tp,
                              __void_t<typename _Tp::first_argument_type,
                                       typename _Tp::second_argument_type>>
    {
      typedef typename _Tp::first_argument_type first_argument_type;
      typedef typename _Tp::second_argument_type second_argument_type;
    };

  /**
   *  Derives from unary_function or binary_function when it
   *  can. Specializations handle all of the easy cases. The primary
   *  template determines what to do with a class type, which may
   *  derive from both unary_function and binary_function.
  */
  template<typename _Tp>
    struct _Reference_wrapper_base
    : _Weak_result_type<_Tp>, _Refwrap_base_arg1<_Tp>, _Refwrap_base_arg2<_Tp>
    { };

  // - a function type (unary)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1)>
    : unary_function<_T1, _Res>
    { };

  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1) const>
    : unary_function<_T1, _Res>
    { };

  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1) volatile>
    : unary_function<_T1, _Res>
    { };

  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1) const volatile>
    : unary_function<_T1, _Res>
    { };

  // - a function type (binary)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2)>
    : binary_function<_T1, _T2, _Res>
    { };

  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2) const>
    : binary_function<_T1, _T2, _Res>
    { };

  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
    : binary_function<_T1, _T2, _Res>
    { };

  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
    : binary_function<_T1, _T2, _Res>
    { };

  // - a function pointer type (unary)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(*)(_T1)>
    : unary_function<_T1, _Res>
    { };

  // - a function pointer type (binary)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
    : binary_function<_T1, _T2, _Res>
    { };

  // - a pointer to member function type (unary, no qualifiers)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)()>
    : unary_function<_T1*, _Res>
    { };

  // - a pointer to member function type (binary, no qualifiers)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
    : binary_function<_T1*, _T2, _Res>
    { };

  // - a pointer to member function type (unary, const)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)() const>
    : unary_function<const _T1*, _Res>
    { };

  // - a pointer to member function type (binary, const)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
    : binary_function<const _T1*, _T2, _Res>
    { };

  // - a pointer to member function type (unary, volatile)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
    : unary_function<volatile _T1*, _Res>
    { };

  // - a pointer to member function type (binary, volatile)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
    : binary_function<volatile _T1*, _T2, _Res>
    { };

  // - a pointer to member function type (unary, const volatile)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
    : unary_function<const volatile _T1*, _Res>
    { };

  // - a pointer to member function type (binary, const volatile)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
    : binary_function<const volatile _T1*, _T2, _Res>
    { };

  /**
   *  @brief Primary class template for reference_wrapper.
   *  @ingroup functors
   *  @{
   */
  template<typename _Tp>
    class reference_wrapper
    : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
    {
      _Tp* _M_data;

    public:
      typedef _Tp type;

      reference_wrapper(_Tp& __indata) noexcept
      : _M_data(std::__addressof(__indata))
      { }

      reference_wrapper(_Tp&&) = delete;

      reference_wrapper(const reference_wrapper&) = default;

      reference_wrapper&
      operator=(const reference_wrapper&) = default;

      operator _Tp&() const noexcept
      { return this->get(); }

      _Tp&
      get() const noexcept
      { return *_M_data; }

      template<typename... _Args>
        typename result_of<_Tp&(_Args&&...)>::type
        operator()(_Args&&... __args) const
        {
          return std::__invoke(get(), std::forward<_Args>(__args)...);
        }
    };


  /// Denotes a reference should be taken to a variable.
  template<typename _Tp>
    inline reference_wrapper<_Tp>
    ref(_Tp& __t) noexcept
    { return reference_wrapper<_Tp>(__t); }

  /// Denotes a const reference should be taken to a variable.
  template<typename _Tp>
    inline reference_wrapper<const _Tp>
    cref(const _Tp& __t) noexcept
    { return reference_wrapper<const _Tp>(__t); }

  template<typename _Tp>
    void ref(const _Tp&&) = delete;

  template<typename _Tp>
    void cref(const _Tp&&) = delete;

  /// Partial specialization.
  template<typename _Tp>
    inline reference_wrapper<_Tp>
    ref(reference_wrapper<_Tp> __t) noexcept
    { return ref(__t.get()); }

  /// Partial specialization.
  template<typename _Tp>
    inline reference_wrapper<const _Tp>
    cref(reference_wrapper<_Tp> __t) noexcept
    { return cref(__t.get()); }

  // @} group functors

  template<typename... _Types>
    struct _Pack : integral_constant<size_t, sizeof...(_Types)>
    { };

  template<typename _From, typename _To, bool = _From::value == _To::value>
    struct _AllConvertible : false_type
    { };

  template<typename... _From, typename... _To>
    struct _AllConvertible<_Pack<_From...>, _Pack<_To...>, true>
    : __and_<is_convertible<_From, _To>...>
    { };

  template<typename _Tp1, typename _Tp2>
    using _NotSame = __not_<is_same<typename std::decay<_Tp1>::type,
                                    typename std::decay<_Tp2>::type>>;

  /**
   * Derives from @c unary_function or @c binary_function, or perhaps
   * nothing, depending on the number of arguments provided. The
   * primary template is the basis case, which derives nothing.
   */
  template<typename _Res, typename... _ArgTypes>
    struct _Maybe_unary_or_binary_function { };

  /// Derives from @c unary_function, as appropriate.
  template<typename _Res, typename _T1>
    struct _Maybe_unary_or_binary_function<_Res, _T1>
    : std::unary_function<_T1, _Res> { };

  /// Derives from @c binary_function, as appropriate.
  template<typename _Res, typename _T1, typename _T2>
    struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
    : std::binary_function<_T1, _T2, _Res> { };

  template<typename _Signature>
    struct _Mem_fn_traits;

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Mem_fn_traits_base
    {
      using __result_type = _Res;
      using __maybe_type
        = _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>;
      using __arity = integral_constant<size_t, sizeof...(_ArgTypes)>;
    };

#define _GLIBCXX_MEM_FN_TRAITS2(_CV, _REF, _LVAL, _RVAL)                \
  template<typename _Res, typename _Class, typename... _ArgTypes>       \
    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes...) _CV _REF>      \
    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>               \
    {                                                                   \
      using __vararg = false_type;                                      \
    };                                                                  \
  template<typename _Res, typename _Class, typename... _ArgTypes>       \
    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes... ...) _CV _REF>  \
    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>               \
    {                                                                   \
      using __vararg = true_type;                                       \
    };

#define _GLIBCXX_MEM_FN_TRAITS(_REF, _LVAL, _RVAL)              \
  _GLIBCXX_MEM_FN_TRAITS2(              , _REF, _LVAL, _RVAL)   \
  _GLIBCXX_MEM_FN_TRAITS2(const         , _REF, _LVAL, _RVAL)   \
  _GLIBCXX_MEM_FN_TRAITS2(volatile      , _REF, _LVAL, _RVAL)   \
  _GLIBCXX_MEM_FN_TRAITS2(const volatile, _REF, _LVAL, _RVAL)

_GLIBCXX_MEM_FN_TRAITS( , true_type, true_type)
_GLIBCXX_MEM_FN_TRAITS(&, true_type, false_type)
_GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)

#undef _GLIBCXX_MEM_FN_TRAITS
#undef _GLIBCXX_MEM_FN_TRAITS2

  template<typename _MemFunPtr,
           bool __is_mem_fn = is_member_function_pointer<_MemFunPtr>::value>
    class _Mem_fn_base
    : public _Mem_fn_traits<_MemFunPtr>::__maybe_type
    {
      using _Traits = _Mem_fn_traits<_MemFunPtr>;

      using _Arity = typename _Traits::__arity;
      using _Varargs = typename _Traits::__vararg;

      template<typename _Func, typename... _BoundArgs>
        friend struct _Bind_check_arity;

      _MemFunPtr _M_pmf;

    public:

      using result_type = typename _Traits::__result_type;

      explicit constexpr
      _Mem_fn_base(_MemFunPtr __pmf) noexcept : _M_pmf(__pmf) { }

      template<typename... _Args>
        auto
        operator()(_Args&&... __args) const
        noexcept(noexcept(
              std::__invoke(_M_pmf, std::forward<_Args>(__args)...)))
        -> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
        { return std::__invoke(_M_pmf, std::forward<_Args>(__args)...); }
    };

  // Partial specialization for member object pointers.
  template<typename _MemObjPtr>
    class _Mem_fn_base<_MemObjPtr, false>
    {
      using _Arity = integral_constant<size_t, 0>;
      using _Varargs = false_type;

      template<typename _Func, typename... _BoundArgs>
        friend struct _Bind_check_arity;

      _MemObjPtr _M_pm;

    public:
      explicit constexpr
      _Mem_fn_base(_MemObjPtr __pm) noexcept : _M_pm(__pm) { }

      template<typename _Tp>
        auto
        operator()(_Tp&& __obj) const
        noexcept(noexcept(std::__invoke(_M_pm, std::forward<_Tp>(__obj))))
        -> decltype(std::__invoke(_M_pm, std::forward<_Tp>(__obj)))
        { return std::__invoke(_M_pm, std::forward<_Tp>(__obj)); }
    };

  template<typename _Res, typename _Class>
    struct _Mem_fn<_Res _Class::*>
    : _Mem_fn_base<_Res _Class::*>
    {
      using _Mem_fn_base<_Res _Class::*>::_Mem_fn_base;
    };

  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 2048.  Unnecessary mem_fn overloads
  /**
   *  @brief Returns a function object that forwards to the member
   *  pointer @a pm.
   *  @ingroup functors
   */
  template<typename _Tp, typename _Class>
    inline _Mem_fn<_Tp _Class::*>
    mem_fn(_Tp _Class::* __pm) noexcept
    {
      return _Mem_fn<_Tp _Class::*>(__pm);
    }

  /**
   *  @brief Determines if the given type _Tp is a function object that
   *  should be treated as a subexpression when evaluating calls to
   *  function objects returned by bind().
   *
   *  C++11 [func.bind.isbind].
   *  @ingroup binders
   */
  template<typename _Tp>
    struct is_bind_expression
    : public false_type { };

  /**
   *  @brief Determines if the given type _Tp is a placeholder in a
   *  bind() expression and, if so, which placeholder it is.
   *
   *  C++11 [func.bind.isplace].
   *  @ingroup binders
   */
  template<typename _Tp>
    struct is_placeholder
    : public integral_constant<int, 0>
    { };

#if __cplusplus > 201402L
  template <typename _Tp> constexpr bool is_bind_expression_v
    = is_bind_expression<_Tp>::value;
  template <typename _Tp> constexpr int is_placeholder_v
    = is_placeholder<_Tp>::value;
#endif // C++17

  /** @brief The type of placeholder objects defined by libstdc++.
   *  @ingroup binders
   */
  template<int _Num> struct _Placeholder { };

  _GLIBCXX_END_NAMESPACE_VERSION

  /** @namespace std::placeholders
   *  @brief ISO C++11 entities sub-namespace for functional.
   *  @ingroup binders
   */
  namespace placeholders
  {
  _GLIBCXX_BEGIN_NAMESPACE_VERSION
  /* Define a large number of placeholders. There is no way to
   * simplify this with variadic templates, because we're introducing
   * unique names for each.
   */
    extern const _Placeholder<1> _1;
    extern const _Placeholder<2> _2;
    extern const _Placeholder<3> _3;
    extern const _Placeholder<4> _4;
    extern const _Placeholder<5> _5;
    extern const _Placeholder<6> _6;
    extern const _Placeholder<7> _7;
    extern const _Placeholder<8> _8;
    extern const _Placeholder<9> _9;
    extern const _Placeholder<10> _10;
    extern const _Placeholder<11> _11;
    extern const _Placeholder<12> _12;
    extern const _Placeholder<13> _13;
    extern const _Placeholder<14> _14;
    extern const _Placeholder<15> _15;
    extern const _Placeholder<16> _16;
    extern const _Placeholder<17> _17;
    extern const _Placeholder<18> _18;
    extern const _Placeholder<19> _19;
    extern const _Placeholder<20> _20;
    extern const _Placeholder<21> _21;
    extern const _Placeholder<22> _22;
    extern const _Placeholder<23> _23;
    extern const _Placeholder<24> _24;
    extern const _Placeholder<25> _25;
    extern const _Placeholder<26> _26;
    extern const _Placeholder<27> _27;
    extern const _Placeholder<28> _28;
    extern const _Placeholder<29> _29;
  _GLIBCXX_END_NAMESPACE_VERSION
  }

  _GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**
   *  Partial specialization of is_placeholder that provides the placeholder
   *  number for the placeholder objects defined by libstdc++.
   *  @ingroup binders
   */
  template<int _Num>
    struct is_placeholder<_Placeholder<_Num> >
    : public integral_constant<int, _Num>
    { };

  template<int _Num>
    struct is_placeholder<const _Placeholder<_Num> >
    : public integral_constant<int, _Num>
    { };


  // Like tuple_element_t but SFINAE-friendly.
  template<std::size_t __i, typename _Tuple>
    using _Safe_tuple_element_t
      = typename enable_if<(__i < tuple_size<_Tuple>::value),
                           tuple_element<__i, _Tuple>>::type::type;

  /**
   *  Maps an argument to bind() into an actual argument to the bound
   *  function object [func.bind.bind]/10. Only the first parameter should
   *  be specified: the rest are used to determine among the various
   *  implementations. Note that, although this class is a function
   *  object, it isn't entirely normal because it takes only two
   *  parameters regardless of the number of parameters passed to the
   *  bind expression. The first parameter is the bound argument and
   *  the second parameter is a tuple containing references to the
   *  rest of the arguments.
   */
  template<typename _Arg,
           bool _IsBindExp = is_bind_expression<_Arg>::value,
           bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
    class _Mu;

  /**
   *  If the argument is reference_wrapper<_Tp>, returns the
   *  underlying reference.
   *  C++11 [func.bind.bind] p10 bullet 1.
   */
  template<typename _Tp>
    class _Mu<reference_wrapper<_Tp>, false, false>
    {
    public:
      /* Note: This won't actually work for const volatile
       * reference_wrappers, because reference_wrapper::get() is const
       * but not volatile-qualified. This might be a defect in the TR.
       */
      template<typename _CVRef, typename _Tuple>
        _Tp&
        operator()(_CVRef& __arg, _Tuple&) const volatile
        { return __arg.get(); }
    };

  /**
   *  If the argument is a bind expression, we invoke the underlying
   *  function object with the same cv-qualifiers as we are given and
   *  pass along all of our arguments (unwrapped).
   *  C++11 [func.bind.bind] p10 bullet 2.
   */
  template<typename _Arg>
    class _Mu<_Arg, true, false>
    {
    public:
      template<typename _CVArg, typename... _Args>
        auto
        operator()(_CVArg& __arg,
                   tuple<_Args...>& __tuple) const volatile
        -> decltype(__arg(declval<_Args>()...))
        {
          // Construct an index tuple and forward to __call
          typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
            _Indexes;
          return this->__call(__arg, __tuple, _Indexes());
        }

    private:
      // Invokes the underlying function object __arg by unpacking all
      // of the arguments in the tuple.
      template<typename _CVArg, typename... _Args, std::size_t... _Indexes>
        auto
        __call(_CVArg& __arg, tuple<_Args...>& __tuple,
               const _Index_tuple<_Indexes...>&) const volatile
        -> decltype(__arg(declval<_Args>()...))
        {
          return __arg(std::get<_Indexes>(std::move(__tuple))...);
        }
    };

  /**
   *  If the argument is a placeholder for the Nth argument, returns
   *  a reference to the Nth argument to the bind function object.
   *  C++11 [func.bind.bind] p10 bullet 3.
   */
  template<typename _Arg>
    class _Mu<_Arg, false, true>
    {
    public:
      template<typename _Tuple>
        _Safe_tuple_element_t<(is_placeholder<_Arg>::value - 1), _Tuple>&&
        operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
        {
          return
            ::std::get<(is_placeholder<_Arg>::value - 1)>(std::move(__tuple));
        }
    };

  /**
   *  If the argument is just a value, returns a reference to that
   *  value. The cv-qualifiers on the reference are determined by the caller.
   *  C++11 [func.bind.bind] p10 bullet 4.
   */
  template<typename _Arg>
    class _Mu<_Arg, false, false>
    {
    public:
      template<typename _CVArg, typename _Tuple>
        _CVArg&&
        operator()(_CVArg&& __arg, _Tuple&) const volatile
        { return std::forward<_CVArg>(__arg); }
    };

  // std::get<I> for volatile-qualified tuples
  template<std::size_t _Ind, typename... _Tp>
    inline auto
    __volget(volatile tuple<_Tp...>& __tuple)
    -> __tuple_element_t<_Ind, tuple<_Tp...>> volatile&
    { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }

  // std::get<I> for const-volatile-qualified tuples
  template<std::size_t _Ind, typename... _Tp>
    inline auto
    __volget(const volatile tuple<_Tp...>& __tuple)
    -> __tuple_element_t<_Ind, tuple<_Tp...>> const volatile&
    { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }

  /// Type of the function object returned from bind().
  template<typename _Signature>
    struct _Bind;

   template<typename _Functor, typename... _Bound_args>
    class _Bind<_Functor(_Bound_args...)>
    : public _Weak_result_type<_Functor>
    {
      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
        _Bound_indexes;

      _Functor _M_f;
      tuple<_Bound_args...> _M_bound_args;

      // Call unqualified
      template<typename _Result, typename... _Args, std::size_t... _Indexes>
        _Result
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
        {
          return std::__invoke(_M_f,
              _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
              );
        }

      // Call as const
      template<typename _Result, typename... _Args, std::size_t... _Indexes>
        _Result
        __call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
        {
          return std::__invoke(_M_f,
              _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
              );
        }

      // Call as volatile
      template<typename _Result, typename... _Args, std::size_t... _Indexes>
        _Result
        __call_v(tuple<_Args...>&& __args,
                 _Index_tuple<_Indexes...>) volatile
        {
          return std::__invoke(_M_f,
              _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
              );
        }

      // Call as const volatile
      template<typename _Result, typename... _Args, std::size_t... _Indexes>
        _Result
        __call_c_v(tuple<_Args...>&& __args,
                   _Index_tuple<_Indexes...>) const volatile
        {
          return std::__invoke(_M_f,
              _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
              );
        }

      template<typename _BoundArg, typename _CallArgs>
        using _Mu_type = decltype(
            _Mu<typename remove_cv<_BoundArg>::type>()(
              std::declval<_BoundArg&>(), std::declval<_CallArgs&>()) );

      template<typename _Fn, typename _CallArgs, typename... _BArgs>
        using _Res_type_impl
          = typename result_of< _Fn&(_Mu_type<_BArgs, _CallArgs>...) >::type;

      template<typename _CallArgs>
        using _Res_type = _Res_type_impl<_Functor, _CallArgs, _Bound_args...>;

      template<typename _CallArgs>
        using __dependent = typename
          enable_if<bool(tuple_size<_CallArgs>::value+1), _Functor>::type;

      template<typename _CallArgs, template<class> class __cv_quals>
        using _Res_type_cv = _Res_type_impl<
          typename __cv_quals<__dependent<_CallArgs>>::type,
          _CallArgs,
          typename __cv_quals<_Bound_args>::type...>;

     public:
      template<typename... _Args>
        explicit _Bind(const _Functor& __f, _Args&&... __args)
        : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
        { }

      template<typename... _Args>
        explicit _Bind(_Functor&& __f, _Args&&... __args)
        : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
        { }

      _Bind(const _Bind&) = default;

      _Bind(_Bind&& __b)
      : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
      { }

      // Call unqualified
      template<typename... _Args,
               typename _Result = _Res_type<tuple<_Args...>>>
        _Result
        operator()(_Args&&... __args)
        {
          return this->__call<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }

      // Call as const
      template<typename... _Args,
               typename _Result = _Res_type_cv<tuple<_Args...>, add_const>>
        _Result
        operator()(_Args&&... __args) const
        {
          return this->__call_c<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }

#if __cplusplus > 201402L
# define _GLIBCXX_DEPR_BIND \
      [[deprecated("std::bind does not support volatile in C++17")]]
#else
# define _GLIBCXX_DEPR_BIND
#endif
      // Call as volatile
      template<typename... _Args,
               typename _Result = _Res_type_cv<tuple<_Args...>, add_volatile>>
        _GLIBCXX_DEPR_BIND
        _Result
        operator()(_Args&&... __args) volatile
        {
          return this->__call_v<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }

      // Call as const volatile
      template<typename... _Args,
               typename _Result = _Res_type_cv<tuple<_Args...>, add_cv>>
        _GLIBCXX_DEPR_BIND
        _Result
        operator()(_Args&&... __args) const volatile
        {
          return this->__call_c_v<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }
    };

  /// Type of the function object returned from bind<R>().
  template<typename _Result, typename _Signature>
    struct _Bind_result;

  template<typename _Result, typename _Functor, typename... _Bound_args>
    class _Bind_result<_Result, _Functor(_Bound_args...)>
    {
      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
        _Bound_indexes;

      _Functor _M_f;
      tuple<_Bound_args...> _M_bound_args;

      // sfinae types
      template<typename _Res>
        using __enable_if_void
          = typename enable_if<is_void<_Res>{}>::type;

      template<typename _Res>
        using __disable_if_void
          = typename enable_if<!is_void<_Res>{}, _Result>::type;

      // Call unqualified
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __disable_if_void<_Res>
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
        {
          return std::__invoke(_M_f, _Mu<_Bound_args>()
                      (std::get<_Indexes>(_M_bound_args), __args)...);
        }

      // Call unqualified, return void
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __enable_if_void<_Res>
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
        {
          std::__invoke(_M_f, _Mu<_Bound_args>()
               (std::get<_Indexes>(_M_bound_args), __args)...);
        }

      // Call as const
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __disable_if_void<_Res>
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
        {
          return std::__invoke(_M_f, _Mu<_Bound_args>()
                      (std::get<_Indexes>(_M_bound_args), __args)...);
        }

      // Call as const, return void
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __enable_if_void<_Res>
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
        {
          std::__invoke(_M_f, _Mu<_Bound_args>()
               (std::get<_Indexes>(_M_bound_args),  __args)...);
        }

      // Call as volatile
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __disable_if_void<_Res>
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) volatile
        {
          return std::__invoke(_M_f, _Mu<_Bound_args>()
                      (__volget<_Indexes>(_M_bound_args), __args)...);
        }

      // Call as volatile, return void
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __enable_if_void<_Res>
        __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) volatile
        {
          std::__invoke(_M_f, _Mu<_Bound_args>()
               (__volget<_Indexes>(_M_bound_args), __args)...);
        }

      // Call as const volatile
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __disable_if_void<_Res>
        __call(tuple<_Args...>&& __args,
               _Index_tuple<_Indexes...>) const volatile
        {
          return std::__invoke(_M_f, _Mu<_Bound_args>()
                      (__volget<_Indexes>(_M_bound_args), __args)...);
        }

      // Call as const volatile, return void
      template<typename _Res, typename... _Args, std::size_t... _Indexes>
        __enable_if_void<_Res>
        __call(tuple<_Args...>&& __args,
               _Index_tuple<_Indexes...>) const volatile
        {
          std::__invoke(_M_f, _Mu<_Bound_args>()
               (__volget<_Indexes>(_M_bound_args), __args)...);
        }

    public:
      typedef _Result result_type;

      template<typename... _Args>
        explicit _Bind_result(const _Functor& __f, _Args&&... __args)
        : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
        { }

      template<typename... _Args>
        explicit _Bind_result(_Functor&& __f, _Args&&... __args)
        : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
        { }

      _Bind_result(const _Bind_result&) = default;

      _Bind_result(_Bind_result&& __b)
      : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
      { }

      // Call unqualified
      template<typename... _Args>
        result_type
        operator()(_Args&&... __args)
        {
          return this->__call<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }

      // Call as const
      template<typename... _Args>
        result_type
        operator()(_Args&&... __args) const
        {
          return this->__call<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }

      // Call as volatile
      template<typename... _Args>
        _GLIBCXX_DEPR_BIND
        result_type
        operator()(_Args&&... __args) volatile
        {
          return this->__call<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }

      // Call as const volatile
      template<typename... _Args>
        _GLIBCXX_DEPR_BIND
        result_type
        operator()(_Args&&... __args) const volatile
        {
          return this->__call<_Result>(
              std::forward_as_tuple(std::forward<_Args>(__args)...),
              _Bound_indexes());
        }
    };
#undef _GLIBCXX_DEPR_BIND

  /**
   *  @brief Class template _Bind is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Signature>
    struct is_bind_expression<_Bind<_Signature> >
    : public true_type { };

  /**
   *  @brief Class template _Bind is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Signature>
    struct is_bind_expression<const _Bind<_Signature> >
    : public true_type { };

  /**
   *  @brief Class template _Bind is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Signature>
    struct is_bind_expression<volatile _Bind<_Signature> >
    : public true_type { };

  /**
   *  @brief Class template _Bind is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Signature>
    struct is_bind_expression<const volatile _Bind<_Signature>>
    : public true_type { };

  /**
   *  @brief Class template _Bind_result is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Result, typename _Signature>
    struct is_bind_expression<_Bind_result<_Result, _Signature>>
    : public true_type { };

  /**
   *  @brief Class template _Bind_result is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Result, typename _Signature>
    struct is_bind_expression<const _Bind_result<_Result, _Signature>>
    : public true_type { };

  /**
   *  @brief Class template _Bind_result is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Result, typename _Signature>
    struct is_bind_expression<volatile _Bind_result<_Result, _Signature>>
    : public true_type { };

  /**
   *  @brief Class template _Bind_result is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Result, typename _Signature>
    struct is_bind_expression<const volatile _Bind_result<_Result, _Signature>>
    : public true_type { };

  template<typename _Func, typename... _BoundArgs>
    struct _Bind_check_arity { };

  template<typename _Ret, typename... _Args, typename... _BoundArgs>
    struct _Bind_check_arity<_Ret (*)(_Args...), _BoundArgs...>
    {
      static_assert(sizeof...(_BoundArgs) == sizeof...(_Args),
                   "Wrong number of arguments for function");
    };

  template<typename _Ret, typename... _Args, typename... _BoundArgs>
    struct _Bind_check_arity<_Ret (*)(_Args......), _BoundArgs...>
    {
      static_assert(sizeof...(_BoundArgs) >= sizeof...(_Args),
                   "Wrong number of arguments for function");
    };

  template<typename _Tp, typename _Class, typename... _BoundArgs>
    struct _Bind_check_arity<_Tp _Class::*, _BoundArgs...>
    {
      using _Arity = typename _Mem_fn<_Tp _Class::*>::_Arity;
      using _Varargs = typename _Mem_fn<_Tp _Class::*>::_Varargs;
      static_assert(_Varargs::value
                    ? sizeof...(_BoundArgs) >= _Arity::value + 1
                    : sizeof...(_BoundArgs) == _Arity::value + 1,
                    "Wrong number of arguments for pointer-to-member");
    };

  // Trait type used to remove std::bind() from overload set via SFINAE
  // when first argument has integer type, so that std::bind() will
  // not be a better match than ::bind() from the BSD Sockets API.
  template<typename _Tp, typename _Tp2 = typename decay<_Tp>::type>
    using __is_socketlike = __or_<is_integral<_Tp2>, is_enum<_Tp2>>;

  template<bool _SocketLike, typename _Func, typename... _BoundArgs>
    struct _Bind_helper
    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
    {
      typedef typename decay<_Func>::type __func_type;
      typedef _Bind<__func_type(typename decay<_BoundArgs>::type...)> type;
    };

  // Partial specialization for is_socketlike == true, does not define
  // nested type so std::bind() will not participate in overload resolution
  // when the first argument might be a socket file descriptor.
  template<typename _Func, typename... _BoundArgs>
    struct _Bind_helper<true, _Func, _BoundArgs...>
    { };

  /**
   *  @brief Function template for std::bind.
   *  @ingroup binders
   */
  template<typename _Func, typename... _BoundArgs>
    inline typename
    _Bind_helper<__is_socketlike<_Func>::value, _Func, _BoundArgs...>::type
    bind(_Func&& __f, _BoundArgs&&... __args)
    {
      typedef _Bind_helper<false, _Func, _BoundArgs...> __helper_type;
      return typename __helper_type::type(std::forward<_Func>(__f),
                                          std::forward<_BoundArgs>(__args)...);
    }

  template<typename _Result, typename _Func, typename... _BoundArgs>
    struct _Bindres_helper
    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
    {
      typedef typename decay<_Func>::type __functor_type;
      typedef _Bind_result<_Result,
                           __functor_type(typename decay<_BoundArgs>::type...)>
        type;
    };

  /**
   *  @brief Function template for std::bind<R>.
   *  @ingroup binders
   */
  template<typename _Result, typename _Func, typename... _BoundArgs>
    inline
    typename _Bindres_helper<_Result, _Func, _BoundArgs...>::type
    bind(_Func&& __f, _BoundArgs&&... __args)
    {
      typedef _Bindres_helper<_Result, _Func, _BoundArgs...> __helper_type;
      return typename __helper_type::type(std::forward<_Func>(__f),
                                          std::forward<_BoundArgs>(__args)...);
    }

  /**
   *  @brief Exception class thrown when class template function's
   *  operator() is called with an empty target.
   *  @ingroup exceptions
   */
  class bad_function_call : public std::exception
  {
  public:
    virtual ~bad_function_call() noexcept;

    const char* what() const noexcept;
  };

  /**
   *  Trait identifying "location-invariant" types, meaning that the
   *  address of the object (or any of its members) will not escape.
   *  Trivially copyable types are location-invariant and users can
   *  specialize this trait for other types.
   */
  template<typename _Tp>
    struct __is_location_invariant
    : is_trivially_copyable<_Tp>::type
    { };

  class _Undefined_class;

  union _Nocopy_types
  {
    void*       _M_object;
    const void* _M_const_object;
    void (*_M_function_pointer)();
    void (_Undefined_class::*_M_member_pointer)();
  };

  union [[gnu::may_alias]] _Any_data
  {
    void*       _M_access()       { return &_M_pod_data[0]; }
    const void* _M_access() const { return &_M_pod_data[0]; }

    template<typename _Tp>
      _Tp&
      _M_access()
      { return *static_cast<_Tp*>(_M_access()); }

    template<typename _Tp>
      const _Tp&
      _M_access() const
      { return *static_cast<const _Tp*>(_M_access()); }

    _Nocopy_types _M_unused;
    char _M_pod_data[sizeof(_Nocopy_types)];
  };

  enum _Manager_operation
  {
    __get_type_info,
    __get_functor_ptr,
    __clone_functor,
    __destroy_functor
  };

  // Simple type wrapper that helps avoid annoying const problems
  // when casting between void pointers and pointers-to-pointers.
  template<typename _Tp>
    struct _Simple_type_wrapper
    {
      _Simple_type_wrapper(_Tp __value) : __value(__value) { }

      _Tp __value;
    };

  template<typename _Tp>
    struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
    : __is_location_invariant<_Tp>
    { };

  template<typename _Signature>
    class function;

  /// Base class of all polymorphic function object wrappers.
  class _Function_base
  {
  public:
    static const std::size_t _M_max_size = sizeof(_Nocopy_types);
    static const std::size_t _M_max_align = __alignof__(_Nocopy_types);

    template<typename _Functor>
      class _Base_manager
      {
      protected:
        static const bool __stored_locally =
        (__is_location_invariant<_Functor>::value
         && sizeof(_Functor) <= _M_max_size
         && __alignof__(_Functor) <= _M_max_align
         && (_M_max_align % __alignof__(_Functor) == 0));

        typedef integral_constant<bool, __stored_locally> _Local_storage;

        // Retrieve a pointer to the function object
        static _Functor*
        _M_get_pointer(const _Any_data& __source)
        {
          const _Functor* __ptr =
            __stored_locally? std::__addressof(__source._M_access<_Functor>())
            /* have stored a pointer */ : __source._M_access<_Functor*>();
          return const_cast<_Functor*>(__ptr);
        }

        // Clone a location-invariant function object that fits within
        // an _Any_data structure.
        static void
        _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
        {
          ::new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
        }

        // Clone a function object that is not location-invariant or
        // that cannot fit into an _Any_data structure.
        static void
        _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
        {
          __dest._M_access<_Functor*>() =
            new _Functor(*__source._M_access<_Functor*>());
        }

        // Destroying a location-invariant object may still require
        // destruction.
        static void
        _M_destroy(_Any_data& __victim, true_type)
        {
          __victim._M_access<_Functor>().~_Functor();
        }

        // Destroying an object located on the heap.
        static void
        _M_destroy(_Any_data& __victim, false_type)
        {
          delete __victim._M_access<_Functor*>();
        }

      public:
        static bool
        _M_manager(_Any_data& __dest, const _Any_data& __source,
                   _Manager_operation __op)
        {
          switch (__op)
            {
#if __cpp_rtti
            case __get_type_info:
              __dest._M_access<const type_info*>() = &typeid(_Functor);
              break;
#endif
            case __get_functor_ptr:
              __dest._M_access<_Functor*>() = _M_get_pointer(__source);
              break;

            case __clone_functor:
              _M_clone(__dest, __source, _Local_storage());
              break;

            case __destroy_functor:
              _M_destroy(__dest, _Local_storage());
              break;
            }
          return false;
        }

        static void
        _M_init_functor(_Any_data& __functor, _Functor&& __f)
        { _M_init_functor(__functor, std::move(__f), _Local_storage()); }

        template<typename _Signature>
          static bool
          _M_not_empty_function(const function<_Signature>& __f)
          { return static_cast<bool>(__f); }

        template<typename _Tp>
          static bool
          _M_not_empty_function(_Tp* __fp)
          { return __fp != nullptr; }

        template<typename _Class, typename _Tp>
          static bool
          _M_not_empty_function(_Tp _Class::* __mp)
          { return __mp != nullptr; }

        template<typename _Tp>
          static bool
          _M_not_empty_function(const _Tp&)
          { return true; }

      private:
        static void
        _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
        { ::new (__functor._M_access()) _Functor(std::move(__f)); }

        static void
        _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
        { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
      };

    template<typename _Functor>
      class _Ref_manager : public _Base_manager<_Functor*>
      {
        typedef _Function_base::_Base_manager<_Functor*> _Base;

      public:
        static bool
        _M_manager(_Any_data& __dest, const _Any_data& __source,
                   _Manager_operation __op)
        {
          switch (__op)
            {
#if __cpp_rtti
            case __get_type_info:
              __dest._M_access<const type_info*>() = &typeid(_Functor);
              break;
#endif
            case __get_functor_ptr:
              __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
              return is_const<_Functor>::value;
              break;

            default:
              _Base::_M_manager(__dest, __source, __op);
            }
          return false;
        }

        static void
        _M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
        {
          _Base::_M_init_functor(__functor, std::__addressof(__f.get()));
        }
      };

    _Function_base() : _M_manager(nullptr) { }

    ~_Function_base()
    {
      if (_M_manager)
        _M_manager(_M_functor, _M_functor, __destroy_functor);
    }


    bool _M_empty() const { return !_M_manager; }

    typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
                                  _Manager_operation);

    _Any_data     _M_functor;
    _Manager_type _M_manager;
  };

  template<typename _Signature, typename _Functor>
    class _Function_handler;

  template<typename _Res, typename _Functor, typename... _ArgTypes>
    class _Function_handler<_Res(_ArgTypes...), _Functor>
    : public _Function_base::_Base_manager<_Functor>
    {
      typedef _Function_base::_Base_manager<_Functor> _Base;

    public:
      static _Res
      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
      {
        return (*_Base::_M_get_pointer(__functor))(
            std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Functor, typename... _ArgTypes>
    class _Function_handler<void(_ArgTypes...), _Functor>
    : public _Function_base::_Base_manager<_Functor>
    {
      typedef _Function_base::_Base_manager<_Functor> _Base;

     public:
      static void
      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
      {
        (*_Base::_M_get_pointer(__functor))(
            std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Res, typename _Functor, typename... _ArgTypes>
    class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
    : public _Function_base::_Ref_manager<_Functor>
    {
      typedef _Function_base::_Ref_manager<_Functor> _Base;

     public:
      static _Res
      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
      {
        return std::__invoke(**_Base::_M_get_pointer(__functor),
                             std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Functor, typename... _ArgTypes>
    class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
    : public _Function_base::_Ref_manager<_Functor>
    {
      typedef _Function_base::_Ref_manager<_Functor> _Base;

     public:
      static void
      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
      {
        std::__invoke(**_Base::_M_get_pointer(__functor),
                      std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Class, typename _Member, typename _Res,
           typename... _ArgTypes>
    class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
    : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
    {
      typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
        _Base;

     public:
      static _Res
      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
      {
        return std::__invoke(_Base::_M_get_pointer(__functor)->__value,
                             std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Class, typename _Member, typename... _ArgTypes>
    class _Function_handler<void(_ArgTypes...), _Member _Class::*>
    : public _Function_base::_Base_manager<
                 _Simple_type_wrapper< _Member _Class::* > >
    {
      typedef _Member _Class::* _Functor;
      typedef _Simple_type_wrapper<_Functor> _Wrapper;
      typedef _Function_base::_Base_manager<_Wrapper> _Base;

    public:
      static bool
      _M_manager(_Any_data& __dest, const _Any_data& __source,
                 _Manager_operation __op)
      {
        switch (__op)
          {
#if __cpp_rtti
          case __get_type_info:
            __dest._M_access<const type_info*>() = &typeid(_Functor);
            break;
#endif
          case __get_functor_ptr:
            __dest._M_access<_Functor*>() =
              &_Base::_M_get_pointer(__source)->__value;
            break;

          default:
            _Base::_M_manager(__dest, __source, __op);
          }
        return false;
      }

      static void
      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
      {
        std::__invoke(_Base::_M_get_pointer(__functor)->__value,
                      std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _From, typename _To>
    using __check_func_return_type
      = __or_<is_void<_To>, is_same<_From, _To>, is_convertible<_From, _To>>;

  /**
   *  @brief Primary class template for std::function.
   *  @ingroup functors
   *
   *  Polymorphic function wrapper.
   */
  template<typename _Res, typename... _ArgTypes>
    class function<_Res(_ArgTypes...)>
    : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
      private _Function_base
    {
      typedef _Res _Signature_type(_ArgTypes...);

      template<typename _Func,
               typename _Res2 = typename result_of<_Func&(_ArgTypes...)>::type>
        struct _Callable : __check_func_return_type<_Res2, _Res> { };

      // Used so the return type convertibility checks aren't done when
      // performing overload resolution for copy construction/assignment.
      template<typename _Tp>
        struct _Callable<function, _Tp> : false_type { };

      template<typename _Cond, typename _Tp>
        using _Requires = typename enable_if<_Cond::value, _Tp>::type;

    public:
      typedef _Res result_type;

      // [3.7.2.1] construct/copy/destroy

      /**
       *  @brief Default construct creates an empty function call wrapper.
       *  @post @c !(bool)*this
       */
      function() noexcept
      : _Function_base() { }

      /**
       *  @brief Creates an empty function call wrapper.
       *  @post @c !(bool)*this
       */
      function(nullptr_t) noexcept
      : _Function_base() { }

      /**
       *  @brief %Function copy constructor.
       *  @param __x A %function object with identical call signature.
       *  @post @c bool(*this) == bool(__x)
       *
       *  The newly-created %function contains a copy of the target of @a
       *  __x (if it has one).
       */
      function(const function& __x);

      /**
       *  @brief %Function move constructor.
       *  @param __x A %function object rvalue with identical call signature.
       *
       *  The newly-created %function contains the target of @a __x
       *  (if it has one).
       */
      function(function&& __x) : _Function_base()
      {
        __x.swap(*this);
      }

      /**
       *  @brief Builds a %function that targets a copy of the incoming
       *  function object.
       *  @param __f A %function object that is callable with parameters of
       *  type @c T1, @c T2, ..., @c TN and returns a value convertible
       *  to @c Res.
       *
       *  The newly-created %function object will target a copy of
       *  @a __f. If @a __f is @c reference_wrapper<F>, then this function
       *  object will contain a reference to the function object @c
       *  __f.get(). If @a __f is a NULL function pointer or NULL
       *  pointer-to-member, the newly-created object will be empty.
       *
       *  If @a __f is a non-NULL function pointer or an object of type @c
       *  reference_wrapper<F>, this function will not throw.
       */
      template<typename _Functor,
               typename = _Requires<__not_<is_same<_Functor, function>>, void>,
               typename = _Requires<_Callable<_Functor>, void>>
        function(_Functor);

      /**
       *  @brief %Function assignment operator.
       *  @param __x A %function with identical call signature.
       *  @post @c (bool)*this == (bool)x
       *  @returns @c *this
       *
       *  The target of @a __x is copied to @c *this. If @a __x has no
       *  target, then @c *this will be empty.
       *
       *  If @a __x targets a function pointer or a reference to a function
       *  object, then this operation will not throw an %exception.
       */
      function&
      operator=(const function& __x)
      {
        function(__x).swap(*this);
        return *this;
      }

      /**
       *  @brief %Function move-assignment operator.
       *  @param __x A %function rvalue with identical call signature.
       *  @returns @c *this
       *
       *  The target of @a __x is moved to @c *this. If @a __x has no
       *  target, then @c *this will be empty.
       *
       *  If @a __x targets a function pointer or a reference to a function
       *  object, then this operation will not throw an %exception.
       */
      function&
      operator=(function&& __x)
      {
        function(std::move(__x)).swap(*this);
        return *this;
      }

      /**
       *  @brief %Function assignment to zero.
       *  @post @c !(bool)*this
       *  @returns @c *this
       *
       *  The target of @c *this is deallocated, leaving it empty.
       */
      function&
      operator=(nullptr_t) noexcept
      {
        if (_M_manager)
          {
            _M_manager(_M_functor, _M_functor, __destroy_functor);
            _M_manager = nullptr;
            _M_invoker = nullptr;
          }
        return *this;
      }

      /**
       *  @brief %Function assignment to a new target.
       *  @param __f A %function object that is callable with parameters of
       *  type @c T1, @c T2, ..., @c TN and returns a value convertible
       *  to @c Res.
       *  @return @c *this
       *
       *  This  %function object wrapper will target a copy of @a
       *  __f. If @a __f is @c reference_wrapper<F>, then this function
       *  object will contain a reference to the function object @c
       *  __f.get(). If @a __f is a NULL function pointer or NULL
       *  pointer-to-member, @c this object will be empty.
       *
       *  If @a __f is a non-NULL function pointer or an object of type @c
       *  reference_wrapper<F>, this function will not throw.
       */
      template<typename _Functor>
        _Requires<_Callable<typename decay<_Functor>::type>, function&>
        operator=(_Functor&& __f)
        {
          function(std::forward<_Functor>(__f)).swap(*this);
          return *this;
        }

      /// @overload
      template<typename _Functor>
        function&
        operator=(reference_wrapper<_Functor> __f) noexcept
        {
          function(__f).swap(*this);
          return *this;
        }

      // [3.7.2.2] function modifiers

      /**
       *  @brief Swap the targets of two %function objects.
       *  @param __x A %function with identical call signature.
       *
       *  Swap the targets of @c this function object and @a __f. This
       *  function will not throw an %exception.
       */
      void swap(function& __x) noexcept
      {
        std::swap(_M_functor, __x._M_functor);
        std::swap(_M_manager, __x._M_manager);
        std::swap(_M_invoker, __x._M_invoker);
      }

      // [3.7.2.3] function capacity

      /**
       *  @brief Determine if the %function wrapper has a target.
       *
       *  @return @c true when this %function object contains a target,
       *  or @c false when it is empty.
       *
       *  This function will not throw an %exception.
       */
      explicit operator bool() const noexcept
      { return !_M_empty(); }

      // [3.7.2.4] function invocation

      /**
       *  @brief Invokes the function targeted by @c *this.
       *  @returns the result of the target.
       *  @throws bad_function_call when @c !(bool)*this
       *
       *  The function call operator invokes the target function object
       *  stored by @c this.
       */
      _Res operator()(_ArgTypes... __args) const;

#if __cpp_rtti
      // [3.7.2.5] function target access
      /**
       *  @brief Determine the type of the target of this function object
       *  wrapper.
       *
       *  @returns the type identifier of the target function object, or
       *  @c typeid(void) if @c !(bool)*this.
       *
       *  This function will not throw an %exception.
       */
      const type_info& target_type() const noexcept;

      /**
       *  @brief Access the stored target function object.
       *
       *  @return Returns a pointer to the stored target function object,
       *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
       *  pointer.
       *
       * This function will not throw an %exception.
       */
      template<typename _Functor>       _Functor* target() noexcept;

      /// @overload
      template<typename _Functor> const _Functor* target() const noexcept;
#endif

    private:
      using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
      _Invoker_type _M_invoker;
  };

  // Out-of-line member definitions.
  template<typename _Res, typename... _ArgTypes>
    function<_Res(_ArgTypes...)>::
    function(const function& __x)
    : _Function_base()
    {
      if (static_cast<bool>(__x))
        {
          __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
          _M_invoker = __x._M_invoker;
          _M_manager = __x._M_manager;
        }
    }

  template<typename _Res, typename... _ArgTypes>
    template<typename _Functor, typename, typename>
      function<_Res(_ArgTypes...)>::
      function(_Functor __f)
      : _Function_base()
      {
        typedef _Function_handler<_Signature_type, _Functor> _My_handler;

        if (_My_handler::_M_not_empty_function(__f))
          {
            _My_handler::_M_init_functor(_M_functor, std::move(__f));
            _M_invoker = &_My_handler::_M_invoke;
            _M_manager = &_My_handler::_M_manager;
          }
      }

  template<typename _Res, typename... _ArgTypes>
    _Res
    function<_Res(_ArgTypes...)>::
    operator()(_ArgTypes... __args) const
    {
      if (_M_empty())
        __throw_bad_function_call();
      return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
    }

#if __cpp_rtti
  template<typename _Res, typename... _ArgTypes>
    const type_info&
    function<_Res(_ArgTypes...)>::
    target_type() const noexcept
    {
      if (_M_manager)
        {
          _Any_data __typeinfo_result;
          _M_manager(__typeinfo_result, _M_functor, __get_type_info);
          return *__typeinfo_result._M_access<const type_info*>();
        }
      else
        return typeid(void);
    }

  template<typename _Res, typename... _ArgTypes>
    template<typename _Functor>
      _Functor*
      function<_Res(_ArgTypes...)>::
      target() noexcept
      {
        if (typeid(_Functor) == target_type() && _M_manager)
          {
            _Any_data __ptr;
            if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
                && !is_const<_Functor>::value)
              return 0;
            else
              return __ptr._M_access<_Functor*>();
          }
        else
          return 0;
      }

  template<typename _Res, typename... _ArgTypes>
    template<typename _Functor>
      const _Functor*
      function<_Res(_ArgTypes...)>::
      target() const noexcept
      {
        if (typeid(_Functor) == target_type() && _M_manager)
          {
            _Any_data __ptr;
            _M_manager(__ptr, _M_functor, __get_functor_ptr);
            return __ptr._M_access<const _Functor*>();
          }
        else
          return 0;
      }
#endif

  // [20.7.15.2.6] null pointer comparisons

  /**
   *  @brief Compares a polymorphic function object wrapper against 0
   *  (the NULL pointer).
   *  @returns @c true if the wrapper has no target, @c false otherwise
   *
   *  This function will not throw an %exception.
   */
  template<typename _Res, typename... _Args>
    inline bool
    operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
    { return !static_cast<bool>(__f); }

  /// @overload
  template<typename _Res, typename... _Args>
    inline bool
    operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
    { return !static_cast<bool>(__f); }

  /**
   *  @brief Compares a polymorphic function object wrapper against 0
   *  (the NULL pointer).
   *  @returns @c false if the wrapper has no target, @c true otherwise
   *
   *  This function will not throw an %exception.
   */
  template<typename _Res, typename... _Args>
    inline bool
    operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
    { return static_cast<bool>(__f); }

  /// @overload
  template<typename _Res, typename... _Args>
    inline bool
    operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
    { return static_cast<bool>(__f); }

  // [20.7.15.2.7] specialized algorithms

  /**
   *  @brief Swap the targets of two polymorphic function object wrappers.
   *
   *  This function will not throw an %exception.
   */
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
  template<typename _Res, typename... _Args>
    inline void
    swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
    { __x.swap(__y); }

#if __cplusplus >= 201402L
  /// Generalized negator.
  template<typename _Fn>
    class _Not_fn
    {
      template<typename _Tp>
        using __is_nothrow_negatable
          = __bool_constant<noexcept(!std::declval<_Tp>())>;

      template<typename _Fn2, typename... _Args>
        using __noexcept_cond = __and_<
          __is_nothrow_callable<_Fn2(_Args&&...)>,
          __is_nothrow_negatable<result_of_t<_Fn2(_Args&&...)>>
        >;

    public:
      template<typename _Fn2>
        _Not_fn(_Fn2&& __fn, int)
        : _M_fn(std::forward<_Fn2>(__fn)) { }

      _Not_fn(const _Not_fn& __fn) = default;
      _Not_fn(_Not_fn&& __fn) = default;
      ~_Not_fn() = default;

      template<typename... _Args>
        auto
        operator()(_Args&&... __args) &
        noexcept(__noexcept_cond<_Fn&, _Args&&...>::value)
        -> decltype(!std::declval<result_of_t<_Fn&(_Args&&...)>>())
        { return !std::__invoke(_M_fn, std::forward<_Args>(__args)...); }

      template<typename... _Args>
        auto
        operator()(_Args&&... __args) const &
        noexcept(__noexcept_cond<const _Fn&, _Args&&...>::value)
        -> decltype(!std::declval<result_of_t<const _Fn&(_Args&&...)>>())
        { return !std::__invoke(_M_fn, std::forward<_Args>(__args)...); }

      template<typename... _Args>
        auto
        operator()(_Args&&... __args) &&
        noexcept(__noexcept_cond<_Fn&&, _Args&&...>::value)
        -> decltype(!std::declval<result_of_t<_Fn&&(_Args&&...)>>())
        {
          return !std::__invoke(std::move(_M_fn),
                                std::forward<_Args>(__args)...);
        }

      template<typename... _Args>
        auto
        operator()(_Args&&... __args) const &&
        noexcept(__noexcept_cond<const _Fn&&, _Args&&...>::value)
        -> decltype(!std::declval<result_of_t<const _Fn&&(_Args&&...)>>())
        {
          return !std::__invoke(std::move(_M_fn),
                                std::forward<_Args>(__args)...);
        }

    private:
      _Fn _M_fn;
    };
#endif // C++14

#if __cplusplus > 201402L

#define __cpp_lib_not_fn 201603

  /// [func.not_fn] Function template not_fn
  template<typename _Fn>
    inline auto
    not_fn(_Fn&& __fn)
    noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
    {
      return _Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
    }

  // Searchers
#define __cpp_lib_boyer_moore_searcher 201603

  template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
    class default_searcher
    {
    public:
      default_searcher(_ForwardIterator1 __pat_first,
                       _ForwardIterator1 __pat_last,
                       _BinaryPredicate __pred = _BinaryPredicate())
      : _M_m(__pat_first, __pat_last, std::move(__pred))
      { }

      template<typename _ForwardIterator2>
        pair<_ForwardIterator2, _ForwardIterator2>
        operator()(_ForwardIterator2 __first, _ForwardIterator2 __last) const
        {
          _ForwardIterator2 __first_ret =
            std::search(__first, __last,
                        std::get<0>(_M_m), std::get<1>(_M_m),
                        std::get<2>(_M_m));
          _ForwardIterator2 __second_ret = __first_ret == __last ?
            __last :  std::next(__first_ret, std::distance(std::get<0>(_M_m),
                                                           std::get<1>(_M_m)));
          return std::make_pair(__first_ret, __second_ret);
        }

    private:
      std::tuple<_ForwardIterator1, _ForwardIterator1, _BinaryPredicate> _M_m;
    };

  template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
    struct __boyer_moore_map_base
    {
      template<typename _RAIter>
        __boyer_moore_map_base(_RAIter __pat, size_t __patlen,
                               _Hash&& __hf, _Pred&& __pred)
        : _M_bad_char{ __patlen, std::move(__hf), std::move(__pred) }
        {
          if (__patlen > 0)
            for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
              _M_bad_char[__pat[__i]] = __patlen - 1 - __i;
        }

      using __diff_type = _Tp;

      __diff_type
      _M_lookup(_Key __key, __diff_type __not_found) const
      {
        auto __iter = _M_bad_char.find(__key);
        if (__iter == _M_bad_char.end())
          return __not_found;
        return __iter->second;
      }

      _Pred
      _M_pred() const { return _M_bad_char.key_eq(); }

      _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _Pred> _M_bad_char;
    };

  template<typename _Tp, size_t _Len, typename _Pred>
    struct __boyer_moore_array_base
    {
      template<typename _RAIter, typename _Unused>
        __boyer_moore_array_base(_RAIter __pat, size_t __patlen,
                                 _Unused&&, _Pred&& __pred)
        : _M_bad_char{ _GLIBCXX_STD_C::array<_Tp, _Len>{}, std::move(__pred) }
        {
          std::get<0>(_M_bad_char).fill(__patlen);
          if (__patlen > 0)
            for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
              {
                auto __ch = __pat[__i];
                using _UCh = std::make_unsigned_t<decltype(__ch)>;
                auto __uch = static_cast<_UCh>(__ch);
                std::get<0>(_M_bad_char)[__uch] = __patlen - 1 - __i;
              }
        }

      using __diff_type = _Tp;

      template<typename _Key>
        __diff_type
        _M_lookup(_Key __key, __diff_type __not_found) const
        {
          auto __ukey = static_cast<std::make_unsigned_t<_Key>>(__key);
          if (__ukey >= _Len)
            return __not_found;
          return std::get<0>(_M_bad_char)[__ukey];
        }

      const _Pred&
      _M_pred() const { return std::get<1>(_M_bad_char); }

      std::tuple<_GLIBCXX_STD_C::array<_Tp, _Len>, _Pred> _M_bad_char;
    };

  template<typename _Pred>
    struct __is_std_equal_to : std::false_type { };

  template<>
    struct __is_std_equal_to<std::equal_to<void>> : std::true_type { };

  // Use __boyer_moore_array_base when pattern consists of narrow characters
  // and uses std::equal_to as the predicate.
  template<typename _RAIter, typename _Hash, typename _Pred,
           typename _Val = typename iterator_traits<_RAIter>::value_type,
           typename _Diff = typename iterator_traits<_RAIter>::difference_type>
    using __boyer_moore_base_t
      = std::conditional_t<sizeof(_Val) == 1 && is_integral<_Val>::value
                           && __is_std_equal_to<_Pred>::value,
                           __boyer_moore_array_base<_Diff, 256, _Pred>,
                           __boyer_moore_map_base<_Val, _Diff, _Hash, _Pred>>;

  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = std::equal_to<>>
    class boyer_moore_searcher
    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
    {
      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
      using typename _Base::__diff_type;

    public:
      boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
                           _Hash __hf = _Hash(),
                           _BinaryPredicate __pred = _BinaryPredicate());

      template<typename _RandomAccessIterator2>
        pair<_RandomAccessIterator2, _RandomAccessIterator2>
        operator()(_RandomAccessIterator2 __first,
                   _RandomAccessIterator2 __last) const;

    private:
      bool
      _M_is_prefix(_RAIter __word, __diff_type __len,
                   __diff_type __pos)
      {
        const auto& __pred = this->_M_pred();
        __diff_type __suffixlen = __len - __pos;
        for (__diff_type __i = 0; __i < __suffixlen; ++__i)
          if (!__pred(__word[__i], __word[__pos + __i]))
            return false;
        return true;
      }

      __diff_type
      _M_suffix_length(_RAIter __word, __diff_type __len,
                       __diff_type __pos)
      {
        const auto& __pred = this->_M_pred();
        __diff_type __i = 0;
        while (__pred(__word[__pos - __i], __word[__len - 1 - __i])
               && __i < __pos)
          {
            ++__i;
          }
        return __i;
      }

      template<typename _Tp>
        __diff_type
        _M_bad_char_shift(_Tp __c) const
        { return this->_M_lookup(__c, _M_pat_end - _M_pat); }

      _RAIter _M_pat;
      _RAIter _M_pat_end;
      _GLIBCXX_STD_C::vector<__diff_type> _M_good_suffix;
    };

  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = std::equal_to<>>
    class boyer_moore_horspool_searcher
    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
    {
      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
      using typename _Base::__diff_type;

    public:
      boyer_moore_horspool_searcher(_RAIter __pat,
                                    _RAIter __pat_end,
                                    _Hash __hf = _Hash(),
                                    _BinaryPredicate __pred
                                    = _BinaryPredicate())
      : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
        _M_pat(__pat), _M_pat_end(__pat_end)
      { }

      template<typename _RandomAccessIterator2>
        pair<_RandomAccessIterator2, _RandomAccessIterator2>
        operator()(_RandomAccessIterator2 __first,
                   _RandomAccessIterator2 __last) const
        {
          const auto& __pred = this->_M_pred();
          auto __patlen = _M_pat_end - _M_pat;
          if (__patlen == 0)
            return std::make_pair(__first, __first);
          auto __len = __last - __first;
          while (__len >= __patlen)
            {
              for (auto __scan = __patlen - 1;
                   __pred(__first[__scan], _M_pat[__scan]); --__scan)
                if (__scan == 0)
                  return std::make_pair(__first,
                                        std::next(__first, __patlen));
              auto __shift = _M_bad_char_shift(__first[__patlen - 1]);
              __len -= __shift;
              __first += __shift;
            }
          return std::make_pair(__last, __last);
        }

    private:
      template<typename _Tp>
        __diff_type
        _M_bad_char_shift(_Tp __c) const
        { return this->_M_lookup(__c, _M_pat_end - _M_pat); }

      _RAIter _M_pat;
      _RAIter _M_pat_end;
    };

  /// Generator function for default_searcher
  template<typename _ForwardIterator,
           typename _BinaryPredicate = std::equal_to<>>
    inline default_searcher<_ForwardIterator, _BinaryPredicate>
    make_default_searcher(_ForwardIterator __pat_first,
                          _ForwardIterator __pat_last,
                          _BinaryPredicate __pred = _BinaryPredicate())
    { return { __pat_first, __pat_last, __pred }; }

  /// Generator function for boyer_moore_searcher
  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = equal_to<>>
    inline boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>
    make_boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
                              _Hash __hf = _Hash(),
                              _BinaryPredicate __pred = _BinaryPredicate())
    { return { __pat_first, __pat_last, std::move(__hf), std::move(__pred) }; }

  /// Generator function for boyer_moore_horspool_searcher
  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = equal_to<>>
    inline boyer_moore_horspool_searcher<_RAIter, _Hash, _BinaryPredicate>
    make_boyer_moore_horspool_searcher(_RAIter __pat_first, _RAIter __pat_last,
                                       _Hash __hf = _Hash(),
                                       _BinaryPredicate __pred
                                       = _BinaryPredicate())
    { return { __pat_first, __pat_last, std::move(__hf), std::move(__pred) }; }

  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
    boyer_moore_searcher(_RAIter __pat, _RAIter __pat_end,
                         _Hash __hf, _BinaryPredicate __pred)
    : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
      _M_pat(__pat), _M_pat_end(__pat_end), _M_good_suffix(__pat_end - __pat)
    {
      auto __patlen = __pat_end - __pat;
      if (__patlen == 0)
        return;
      __diff_type __last_prefix = __patlen - 1;
      for (__diff_type __p = __patlen - 1; __p >= 0; --__p)
        {
          if (_M_is_prefix(__pat, __patlen, __p + 1))
            __last_prefix = __p + 1;
          _M_good_suffix[__p] = __last_prefix + (__patlen - 1 - __p);
        }
      for (__diff_type __p = 0; __p < __patlen - 1; ++__p)
        {
          auto __slen = _M_suffix_length(__pat, __patlen, __p);
          auto __pos = __patlen - 1 - __slen;
          if (!__pred(__pat[__p - __slen], __pat[__pos]))
            _M_good_suffix[__pos] = __patlen - 1 - __p + __slen;
        }
    }

  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
  template<typename _RandomAccessIterator2>
    pair<_RandomAccessIterator2, _RandomAccessIterator2>
    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
    operator()(_RandomAccessIterator2 __first,
               _RandomAccessIterator2 __last) const
    {
      auto __patlen = _M_pat_end - _M_pat;
      if (__patlen == 0)
        return std::make_pair(__first, __first);
      const auto& __pred = this->_M_pred();
      __diff_type __i = __patlen - 1;
      auto __stringlen = __last - __first;
      while (__i < __stringlen)
        {
          __diff_type __j = __patlen - 1;
          while (__j >= 0 && __pred(__first[__i], _M_pat[__j]))
            {
              --__i;
              --__j;
            }
          if (__j < 0)
            return std::make_pair(__first + __i + 1, std::next(__first,
                                                               __patlen));
          __i += std::max(_M_bad_char_shift(__first[__i]),
                          _M_good_suffix[__j]);
        }
      return std::make_pair(__last, __last);
    }

#endif // C++17

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // C++11

#endif // _GLIBCXX_FUNCTIONAL