xref: /netbsd-src/external/gpl3/gcc/dist/libstdc++-v3/include/std/functional (revision b1e838363e3c6fc78a55519254d99869742dd33c)
1// <functional> -*- C++ -*-
2
3// Copyright (C) 2001-2022 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/*
26 * Copyright (c) 1997
27 * Silicon Graphics Computer Systems, Inc.
28 *
29 * Permission to use, copy, modify, distribute and sell this software
30 * and its documentation for any purpose is hereby granted without fee,
31 * provided that the above copyright notice appear in all copies and
32 * that both that copyright notice and this permission notice appear
33 * in supporting documentation.  Silicon Graphics makes no
34 * representations about the suitability of this software for any
35 * purpose.  It is provided "as is" without express or implied warranty.
36 *
37 */
38
39/** @file include/functional
40 *  This is a Standard C++ Library header.
41 */
42
43#ifndef _GLIBCXX_FUNCTIONAL
44#define _GLIBCXX_FUNCTIONAL 1
45
46#pragma GCC system_header
47
48#include <bits/c++config.h>
49#include <bits/stl_function.h>
50
51#if __cplusplus >= 201103L
52
53#include <new>
54#include <tuple>
55#include <type_traits>
56#include <bits/functional_hash.h>
57#include <bits/invoke.h>
58#include <bits/refwrap.h>	// std::reference_wrapper and _Mem_fn_traits
59#include <bits/std_function.h>	// std::function
60#if __cplusplus > 201402L
61# include <unordered_map>
62# include <vector>
63# include <array>
64# include <bits/stl_algo.h>
65#endif
66#if __cplusplus > 201703L
67# include <bits/ranges_cmp.h>
68# include <compare>
69#endif
70#if __cplusplus > 202002L
71# include <bits/move_only_function.h>
72#endif
73
74#endif // C++11
75
76namespace std _GLIBCXX_VISIBILITY(default)
77{
78_GLIBCXX_BEGIN_NAMESPACE_VERSION
79
80  /** @brief The type of placeholder objects defined by libstdc++.
81   *  @ingroup binders
82   *  @since C++11
83   */
84  template<int _Num> struct _Placeholder { };
85
86#if __cplusplus >= 201103L
87
88#if __cplusplus >= 201703L
89# define __cpp_lib_invoke 201411L
90# if __cplusplus > 201703L
91#  define __cpp_lib_constexpr_functional 201907L
92# endif
93
94  /** Invoke a callable object.
95   *
96   * `std::invoke` takes a callable object as its first argument and calls it
97   * with the remaining arguments. The callable object can be a pointer or
98   * reference to a function, a lambda closure, a class with `operator()`,
99   * or even a pointer-to-member.  For a pointer-to-member the first argument
100   * must be a reference or pointer to the object that the pointer-to-member
101   * will be applied to.
102   *
103   *  @since C++17
104   */
105  template<typename _Callable, typename... _Args>
106    inline _GLIBCXX20_CONSTEXPR invoke_result_t<_Callable, _Args...>
107    invoke(_Callable&& __fn, _Args&&... __args)
108    noexcept(is_nothrow_invocable_v<_Callable, _Args...>)
109    {
110      return std::__invoke(std::forward<_Callable>(__fn),
111			   std::forward<_Args>(__args)...);
112    }
113
114#if __cplusplus > 202002L
115# define __cpp_lib_invoke_r 202106L
116
117  /** Invoke a callable object and convert the result to `_Res`.
118   *
119   * `std::invoke_r<R>(f, args...)` is equivalent to `std::invoke(f, args...)`
120   * with the result implicitly converted to `R`.
121   *
122   *  @since C++23
123   */
124  template<typename _Res, typename _Callable, typename... _Args>
125    requires is_invocable_r_v<_Res, _Callable, _Args...>
126    constexpr _Res
127    invoke_r(_Callable&& __fn, _Args&&... __args)
128    noexcept(is_nothrow_invocable_r_v<_Res, _Callable, _Args...>)
129    {
130      return std::__invoke_r<_Res>(std::forward<_Callable>(__fn),
131				   std::forward<_Args>(__args)...);
132    }
133#endif // C++23
134#endif // C++17
135
136  /// @cond undocumented
137
138  template<typename _MemFunPtr,
139	   bool __is_mem_fn = is_member_function_pointer<_MemFunPtr>::value>
140    class _Mem_fn_base
141    : public _Mem_fn_traits<_MemFunPtr>::__maybe_type
142    {
143      using _Traits = _Mem_fn_traits<_MemFunPtr>;
144
145      using _Arity = typename _Traits::__arity;
146      using _Varargs = typename _Traits::__vararg;
147
148      template<typename _Func, typename... _BoundArgs>
149	friend struct _Bind_check_arity;
150
151      _MemFunPtr _M_pmf;
152
153    public:
154
155      using result_type = typename _Traits::__result_type;
156
157      explicit constexpr
158      _Mem_fn_base(_MemFunPtr __pmf) noexcept : _M_pmf(__pmf) { }
159
160      template<typename... _Args>
161	_GLIBCXX20_CONSTEXPR
162	auto
163	operator()(_Args&&... __args) const
164	noexcept(noexcept(
165	      std::__invoke(_M_pmf, std::forward<_Args>(__args)...)))
166	-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
167	{ return std::__invoke(_M_pmf, std::forward<_Args>(__args)...); }
168    };
169
170  // Partial specialization for member object pointers.
171  template<typename _MemObjPtr>
172    class _Mem_fn_base<_MemObjPtr, false>
173    {
174      using _Arity = integral_constant<size_t, 0>;
175      using _Varargs = false_type;
176
177      template<typename _Func, typename... _BoundArgs>
178	friend struct _Bind_check_arity;
179
180      _MemObjPtr _M_pm;
181
182    public:
183      explicit constexpr
184      _Mem_fn_base(_MemObjPtr __pm) noexcept : _M_pm(__pm) { }
185
186      template<typename _Tp>
187	_GLIBCXX20_CONSTEXPR
188	auto
189	operator()(_Tp&& __obj) const
190	noexcept(noexcept(std::__invoke(_M_pm, std::forward<_Tp>(__obj))))
191	-> decltype(std::__invoke(_M_pm, std::forward<_Tp>(__obj)))
192	{ return std::__invoke(_M_pm, std::forward<_Tp>(__obj)); }
193    };
194
195  template<typename _MemberPointer>
196    struct _Mem_fn; // undefined
197
198  template<typename _Res, typename _Class>
199    struct _Mem_fn<_Res _Class::*>
200    : _Mem_fn_base<_Res _Class::*>
201    {
202      using _Mem_fn_base<_Res _Class::*>::_Mem_fn_base;
203    };
204  /// @endcond
205
206  // _GLIBCXX_RESOLVE_LIB_DEFECTS
207  // 2048.  Unnecessary mem_fn overloads
208  /**
209   * @brief Returns a function object that forwards to the member pointer
210   * pointer `pm`.
211   *
212   * This allows a pointer-to-member to be transformed into a function object
213   * that can be called with an object expression as its first argument.
214   *
215   * For a pointer-to-data-member the result must be called with exactly one
216   * argument, the object expression that would be used as the first operand
217   * in a `obj.*memptr` or `objp->*memptr` expression.
218   *
219   * For a pointer-to-member-function the result must be called with an object
220   * expression and any additional arguments to pass to the member function,
221   * as in an expression like `(obj.*memfun)(args...)` or
222   * `(objp->*memfun)(args...)`.
223   *
224   * The object expression can be a pointer, reference, `reference_wrapper`,
225   * or smart pointer, and the call wrapper will dereference it as needed
226   * to apply the pointer-to-member.
227   *
228   * @ingroup functors
229   * @since C++11
230   */
231  template<typename _Tp, typename _Class>
232    _GLIBCXX20_CONSTEXPR
233    inline _Mem_fn<_Tp _Class::*>
234    mem_fn(_Tp _Class::* __pm) noexcept
235    {
236      return _Mem_fn<_Tp _Class::*>(__pm);
237    }
238
239  /**
240   * @brief Trait that identifies a bind expression.
241   *
242   * Determines if the given type `_Tp` is a function object that
243   * should be treated as a subexpression when evaluating calls to
244   * function objects returned by `std::bind`.
245   *
246   * C++11 [func.bind.isbind].
247   * @ingroup binders
248   * @since C++11
249   */
250  template<typename _Tp>
251    struct is_bind_expression
252    : public false_type { };
253
254  /**
255   *  @brief Determines if the given type _Tp is a placeholder in a
256   *  bind() expression and, if so, which placeholder it is.
257   *
258   *  C++11 [func.bind.isplace].
259   *  @ingroup binders
260   *  @since C++11
261   */
262  template<typename _Tp>
263    struct is_placeholder
264    : public integral_constant<int, 0>
265    { };
266
267#if __cplusplus > 201402L
268  template <typename _Tp> inline constexpr bool is_bind_expression_v
269    = is_bind_expression<_Tp>::value;
270  template <typename _Tp> inline constexpr int is_placeholder_v
271    = is_placeholder<_Tp>::value;
272#endif // C++17
273
274  /** @namespace std::placeholders
275   *  @brief ISO C++ 2011 namespace for std::bind placeholders.
276   *  @ingroup binders
277   *  @since C++11
278   */
279  namespace placeholders
280  {
281  /* Define a large number of placeholders. There is no way to
282   * simplify this with variadic templates, because we're introducing
283   * unique names for each.
284   */
285    extern const _Placeholder<1> _1;
286    extern const _Placeholder<2> _2;
287    extern const _Placeholder<3> _3;
288    extern const _Placeholder<4> _4;
289    extern const _Placeholder<5> _5;
290    extern const _Placeholder<6> _6;
291    extern const _Placeholder<7> _7;
292    extern const _Placeholder<8> _8;
293    extern const _Placeholder<9> _9;
294    extern const _Placeholder<10> _10;
295    extern const _Placeholder<11> _11;
296    extern const _Placeholder<12> _12;
297    extern const _Placeholder<13> _13;
298    extern const _Placeholder<14> _14;
299    extern const _Placeholder<15> _15;
300    extern const _Placeholder<16> _16;
301    extern const _Placeholder<17> _17;
302    extern const _Placeholder<18> _18;
303    extern const _Placeholder<19> _19;
304    extern const _Placeholder<20> _20;
305    extern const _Placeholder<21> _21;
306    extern const _Placeholder<22> _22;
307    extern const _Placeholder<23> _23;
308    extern const _Placeholder<24> _24;
309    extern const _Placeholder<25> _25;
310    extern const _Placeholder<26> _26;
311    extern const _Placeholder<27> _27;
312    extern const _Placeholder<28> _28;
313    extern const _Placeholder<29> _29;
314  }
315
316  /**
317   *  Partial specialization of is_placeholder that provides the placeholder
318   *  number for the placeholder objects defined by libstdc++.
319   *  @ingroup binders
320   *  @since C++11
321   */
322  template<int _Num>
323    struct is_placeholder<_Placeholder<_Num> >
324    : public integral_constant<int, _Num>
325    { };
326
327  template<int _Num>
328    struct is_placeholder<const _Placeholder<_Num> >
329    : public integral_constant<int, _Num>
330    { };
331
332  /// @cond undocumented
333
334  // Like tuple_element_t but SFINAE-friendly.
335  template<std::size_t __i, typename _Tuple>
336    using _Safe_tuple_element_t
337      = typename enable_if<(__i < tuple_size<_Tuple>::value),
338			   tuple_element<__i, _Tuple>>::type::type;
339
340  /**
341   *  Maps an argument to bind() into an actual argument to the bound
342   *  function object [func.bind.bind]/10. Only the first parameter should
343   *  be specified: the rest are used to determine among the various
344   *  implementations. Note that, although this class is a function
345   *  object, it isn't entirely normal because it takes only two
346   *  parameters regardless of the number of parameters passed to the
347   *  bind expression. The first parameter is the bound argument and
348   *  the second parameter is a tuple containing references to the
349   *  rest of the arguments.
350   */
351  template<typename _Arg,
352	   bool _IsBindExp = is_bind_expression<_Arg>::value,
353	   bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
354    class _Mu;
355
356  /**
357   *  If the argument is reference_wrapper<_Tp>, returns the
358   *  underlying reference.
359   *  C++11 [func.bind.bind] p10 bullet 1.
360   */
361  template<typename _Tp>
362    class _Mu<reference_wrapper<_Tp>, false, false>
363    {
364    public:
365      /* Note: This won't actually work for const volatile
366       * reference_wrappers, because reference_wrapper::get() is const
367       * but not volatile-qualified. This might be a defect in the TR.
368       */
369      template<typename _CVRef, typename _Tuple>
370	_GLIBCXX20_CONSTEXPR
371	_Tp&
372	operator()(_CVRef& __arg, _Tuple&) const volatile
373	{ return __arg.get(); }
374    };
375
376  /**
377   *  If the argument is a bind expression, we invoke the underlying
378   *  function object with the same cv-qualifiers as we are given and
379   *  pass along all of our arguments (unwrapped).
380   *  C++11 [func.bind.bind] p10 bullet 2.
381   */
382  template<typename _Arg>
383    class _Mu<_Arg, true, false>
384    {
385    public:
386      template<typename _CVArg, typename... _Args>
387	_GLIBCXX20_CONSTEXPR
388	auto
389	operator()(_CVArg& __arg,
390		   tuple<_Args...>& __tuple) const volatile
391	-> decltype(__arg(declval<_Args>()...))
392	{
393	  // Construct an index tuple and forward to __call
394	  typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
395	    _Indexes;
396	  return this->__call(__arg, __tuple, _Indexes());
397	}
398
399    private:
400      // Invokes the underlying function object __arg by unpacking all
401      // of the arguments in the tuple.
402      template<typename _CVArg, typename... _Args, std::size_t... _Indexes>
403	_GLIBCXX20_CONSTEXPR
404	auto
405	__call(_CVArg& __arg, tuple<_Args...>& __tuple,
406	       const _Index_tuple<_Indexes...>&) const volatile
407	-> decltype(__arg(declval<_Args>()...))
408	{
409	  return __arg(std::get<_Indexes>(std::move(__tuple))...);
410	}
411    };
412
413  /**
414   *  If the argument is a placeholder for the Nth argument, returns
415   *  a reference to the Nth argument to the bind function object.
416   *  C++11 [func.bind.bind] p10 bullet 3.
417   */
418  template<typename _Arg>
419    class _Mu<_Arg, false, true>
420    {
421    public:
422      template<typename _Tuple>
423	_GLIBCXX20_CONSTEXPR
424	_Safe_tuple_element_t<(is_placeholder<_Arg>::value - 1), _Tuple>&&
425	operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
426	{
427	  return
428	    ::std::get<(is_placeholder<_Arg>::value - 1)>(std::move(__tuple));
429	}
430    };
431
432  /**
433   *  If the argument is just a value, returns a reference to that
434   *  value. The cv-qualifiers on the reference are determined by the caller.
435   *  C++11 [func.bind.bind] p10 bullet 4.
436   */
437  template<typename _Arg>
438    class _Mu<_Arg, false, false>
439    {
440    public:
441      template<typename _CVArg, typename _Tuple>
442	_GLIBCXX20_CONSTEXPR
443	_CVArg&&
444	operator()(_CVArg&& __arg, _Tuple&) const volatile
445	{ return std::forward<_CVArg>(__arg); }
446    };
447
448  // std::get<I> for volatile-qualified tuples
449  template<std::size_t _Ind, typename... _Tp>
450    inline auto
451    __volget(volatile tuple<_Tp...>& __tuple)
452    -> __tuple_element_t<_Ind, tuple<_Tp...>> volatile&
453    { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
454
455  // std::get<I> for const-volatile-qualified tuples
456  template<std::size_t _Ind, typename... _Tp>
457    inline auto
458    __volget(const volatile tuple<_Tp...>& __tuple)
459    -> __tuple_element_t<_Ind, tuple<_Tp...>> const volatile&
460    { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
461
462  /// @endcond
463
464#if __cplusplus == 201703L && _GLIBCXX_USE_DEPRECATED
465# define _GLIBCXX_VOLATILE_BIND
466// _GLIBCXX_RESOLVE_LIB_DEFECTS
467// 2487. bind() should be const-overloaded, not cv-overloaded
468# define _GLIBCXX_DEPR_BIND \
469      [[deprecated("std::bind does not support volatile in C++17")]]
470#elif __cplusplus < 201703L
471# define _GLIBCXX_VOLATILE_BIND
472# define _GLIBCXX_DEPR_BIND
473#endif
474
475  /// Type of the function object returned from bind().
476  template<typename _Signature>
477    class _Bind;
478
479   template<typename _Functor, typename... _Bound_args>
480    class _Bind<_Functor(_Bound_args...)>
481    : public _Weak_result_type<_Functor>
482    {
483      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
484	_Bound_indexes;
485
486      _Functor _M_f;
487      tuple<_Bound_args...> _M_bound_args;
488
489      // Call unqualified
490      template<typename _Result, typename... _Args, std::size_t... _Indexes>
491	_GLIBCXX20_CONSTEXPR
492	_Result
493	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
494	{
495	  return std::__invoke(_M_f,
496	      _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
497	      );
498	}
499
500      // Call as const
501      template<typename _Result, typename... _Args, std::size_t... _Indexes>
502	_GLIBCXX20_CONSTEXPR
503	_Result
504	__call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
505	{
506	  return std::__invoke(_M_f,
507	      _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
508	      );
509	}
510
511#ifdef _GLIBCXX_VOLATILE_BIND
512      // Call as volatile
513      template<typename _Result, typename... _Args, std::size_t... _Indexes>
514	_Result
515	__call_v(tuple<_Args...>&& __args,
516		 _Index_tuple<_Indexes...>) volatile
517	{
518	  return std::__invoke(_M_f,
519	      _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
520	      );
521	}
522
523      // Call as const volatile
524      template<typename _Result, typename... _Args, std::size_t... _Indexes>
525	_Result
526	__call_c_v(tuple<_Args...>&& __args,
527		   _Index_tuple<_Indexes...>) const volatile
528	{
529	  return std::__invoke(_M_f,
530	      _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
531	      );
532	}
533#endif // volatile
534
535      template<typename _BoundArg, typename _CallArgs>
536	using _Mu_type = decltype(
537	    _Mu<typename remove_cv<_BoundArg>::type>()(
538	      std::declval<_BoundArg&>(), std::declval<_CallArgs&>()) );
539
540      template<typename _Fn, typename _CallArgs, typename... _BArgs>
541	using _Res_type_impl
542	  = typename result_of< _Fn&(_Mu_type<_BArgs, _CallArgs>&&...) >::type;
543
544      template<typename _CallArgs>
545	using _Res_type = _Res_type_impl<_Functor, _CallArgs, _Bound_args...>;
546
547      template<typename _CallArgs>
548	using __dependent = typename
549	  enable_if<bool(tuple_size<_CallArgs>::value+1), _Functor>::type;
550
551      template<typename _CallArgs, template<class> class __cv_quals>
552	using _Res_type_cv = _Res_type_impl<
553	  typename __cv_quals<__dependent<_CallArgs>>::type,
554	  _CallArgs,
555	  typename __cv_quals<_Bound_args>::type...>;
556
557     public:
558      template<typename... _Args>
559	explicit _GLIBCXX20_CONSTEXPR
560	_Bind(const _Functor& __f, _Args&&... __args)
561	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
562	{ }
563
564      template<typename... _Args>
565	explicit _GLIBCXX20_CONSTEXPR
566	_Bind(_Functor&& __f, _Args&&... __args)
567	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
568	{ }
569
570      _Bind(const _Bind&) = default;
571      _Bind(_Bind&&) = default;
572
573      // Call unqualified
574      template<typename... _Args,
575	       typename _Result = _Res_type<tuple<_Args...>>>
576	_GLIBCXX20_CONSTEXPR
577	_Result
578	operator()(_Args&&... __args)
579	{
580	  return this->__call<_Result>(
581	      std::forward_as_tuple(std::forward<_Args>(__args)...),
582	      _Bound_indexes());
583	}
584
585      // Call as const
586      template<typename... _Args,
587	       typename _Result = _Res_type_cv<tuple<_Args...>, add_const>>
588	_GLIBCXX20_CONSTEXPR
589	_Result
590	operator()(_Args&&... __args) const
591	{
592	  return this->__call_c<_Result>(
593	      std::forward_as_tuple(std::forward<_Args>(__args)...),
594	      _Bound_indexes());
595	}
596
597#ifdef _GLIBCXX_VOLATILE_BIND
598      // Call as volatile
599      template<typename... _Args,
600	       typename _Result = _Res_type_cv<tuple<_Args...>, add_volatile>>
601	_GLIBCXX_DEPR_BIND
602	_Result
603	operator()(_Args&&... __args) volatile
604	{
605	  return this->__call_v<_Result>(
606	      std::forward_as_tuple(std::forward<_Args>(__args)...),
607	      _Bound_indexes());
608	}
609
610      // Call as const volatile
611      template<typename... _Args,
612	       typename _Result = _Res_type_cv<tuple<_Args...>, add_cv>>
613	_GLIBCXX_DEPR_BIND
614	_Result
615	operator()(_Args&&... __args) const volatile
616	{
617	  return this->__call_c_v<_Result>(
618	      std::forward_as_tuple(std::forward<_Args>(__args)...),
619	      _Bound_indexes());
620	}
621#endif // volatile
622    };
623
624  /// Type of the function object returned from bind<R>().
625  template<typename _Result, typename _Signature>
626    class _Bind_result;
627
628  template<typename _Result, typename _Functor, typename... _Bound_args>
629    class _Bind_result<_Result, _Functor(_Bound_args...)>
630    {
631      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
632	_Bound_indexes;
633
634      _Functor _M_f;
635      tuple<_Bound_args...> _M_bound_args;
636
637      // Call unqualified
638      template<typename _Res, typename... _Args, std::size_t... _Indexes>
639	_GLIBCXX20_CONSTEXPR
640	_Res
641	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
642	{
643	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
644		      (std::get<_Indexes>(_M_bound_args), __args)...);
645	}
646
647      // Call as const
648      template<typename _Res, typename... _Args, std::size_t... _Indexes>
649	_GLIBCXX20_CONSTEXPR
650	_Res
651	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
652	{
653	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
654		      (std::get<_Indexes>(_M_bound_args), __args)...);
655	}
656
657#ifdef _GLIBCXX_VOLATILE_BIND
658      // Call as volatile
659      template<typename _Res, typename... _Args, std::size_t... _Indexes>
660	_Res
661	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) volatile
662	{
663	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
664		      (__volget<_Indexes>(_M_bound_args), __args)...);
665	}
666
667      // Call as const volatile
668      template<typename _Res, typename... _Args, std::size_t... _Indexes>
669	_Res
670	__call(tuple<_Args...>&& __args,
671	       _Index_tuple<_Indexes...>) const volatile
672	{
673	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
674		      (__volget<_Indexes>(_M_bound_args), __args)...);
675	}
676#endif // volatile
677
678    public:
679      typedef _Result result_type;
680
681      template<typename... _Args>
682	explicit _GLIBCXX20_CONSTEXPR
683	_Bind_result(const _Functor& __f, _Args&&... __args)
684	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
685	{ }
686
687      template<typename... _Args>
688	explicit _GLIBCXX20_CONSTEXPR
689	_Bind_result(_Functor&& __f, _Args&&... __args)
690	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
691	{ }
692
693      _Bind_result(const _Bind_result&) = default;
694      _Bind_result(_Bind_result&&) = default;
695
696      // Call unqualified
697      template<typename... _Args>
698	_GLIBCXX20_CONSTEXPR
699	result_type
700	operator()(_Args&&... __args)
701	{
702	  return this->__call<_Result>(
703	      std::forward_as_tuple(std::forward<_Args>(__args)...),
704	      _Bound_indexes());
705	}
706
707      // Call as const
708      template<typename... _Args>
709	_GLIBCXX20_CONSTEXPR
710	result_type
711	operator()(_Args&&... __args) const
712	{
713	  return this->__call<_Result>(
714	      std::forward_as_tuple(std::forward<_Args>(__args)...),
715	      _Bound_indexes());
716	}
717
718#ifdef _GLIBCXX_VOLATILE_BIND
719      // Call as volatile
720      template<typename... _Args>
721	_GLIBCXX_DEPR_BIND
722	result_type
723	operator()(_Args&&... __args) volatile
724	{
725	  return this->__call<_Result>(
726	      std::forward_as_tuple(std::forward<_Args>(__args)...),
727	      _Bound_indexes());
728	}
729
730      // Call as const volatile
731      template<typename... _Args>
732	_GLIBCXX_DEPR_BIND
733	result_type
734	operator()(_Args&&... __args) const volatile
735	{
736	  return this->__call<_Result>(
737	      std::forward_as_tuple(std::forward<_Args>(__args)...),
738	      _Bound_indexes());
739	}
740#else
741      template<typename... _Args>
742	void operator()(_Args&&...) const volatile = delete;
743#endif // volatile
744    };
745
746#undef _GLIBCXX_VOLATILE_BIND
747#undef _GLIBCXX_DEPR_BIND
748
749  /**
750   *  @brief Class template _Bind is always a bind expression.
751   *  @ingroup binders
752   */
753  template<typename _Signature>
754    struct is_bind_expression<_Bind<_Signature> >
755    : public true_type { };
756
757  /**
758   *  @brief Class template _Bind is always a bind expression.
759   *  @ingroup binders
760   */
761  template<typename _Signature>
762    struct is_bind_expression<const _Bind<_Signature> >
763    : public true_type { };
764
765  /**
766   *  @brief Class template _Bind is always a bind expression.
767   *  @ingroup binders
768   */
769  template<typename _Signature>
770    struct is_bind_expression<volatile _Bind<_Signature> >
771    : public true_type { };
772
773  /**
774   *  @brief Class template _Bind is always a bind expression.
775   *  @ingroup binders
776   */
777  template<typename _Signature>
778    struct is_bind_expression<const volatile _Bind<_Signature>>
779    : public true_type { };
780
781  /**
782   *  @brief Class template _Bind_result is always a bind expression.
783   *  @ingroup binders
784   */
785  template<typename _Result, typename _Signature>
786    struct is_bind_expression<_Bind_result<_Result, _Signature>>
787    : public true_type { };
788
789  /**
790   *  @brief Class template _Bind_result is always a bind expression.
791   *  @ingroup binders
792   */
793  template<typename _Result, typename _Signature>
794    struct is_bind_expression<const _Bind_result<_Result, _Signature>>
795    : public true_type { };
796
797  /**
798   *  @brief Class template _Bind_result is always a bind expression.
799   *  @ingroup binders
800   */
801  template<typename _Result, typename _Signature>
802    struct is_bind_expression<volatile _Bind_result<_Result, _Signature>>
803    : public true_type { };
804
805  /**
806   *  @brief Class template _Bind_result is always a bind expression.
807   *  @ingroup binders
808   */
809  template<typename _Result, typename _Signature>
810    struct is_bind_expression<const volatile _Bind_result<_Result, _Signature>>
811    : public true_type { };
812
813  template<typename _Func, typename... _BoundArgs>
814    struct _Bind_check_arity { };
815
816  template<typename _Ret, typename... _Args, typename... _BoundArgs>
817    struct _Bind_check_arity<_Ret (*)(_Args...), _BoundArgs...>
818    {
819      static_assert(sizeof...(_BoundArgs) == sizeof...(_Args),
820                   "Wrong number of arguments for function");
821    };
822
823  template<typename _Ret, typename... _Args, typename... _BoundArgs>
824    struct _Bind_check_arity<_Ret (*)(_Args......), _BoundArgs...>
825    {
826      static_assert(sizeof...(_BoundArgs) >= sizeof...(_Args),
827                   "Wrong number of arguments for function");
828    };
829
830  template<typename _Tp, typename _Class, typename... _BoundArgs>
831    struct _Bind_check_arity<_Tp _Class::*, _BoundArgs...>
832    {
833      using _Arity = typename _Mem_fn<_Tp _Class::*>::_Arity;
834      using _Varargs = typename _Mem_fn<_Tp _Class::*>::_Varargs;
835      static_assert(_Varargs::value
836		    ? sizeof...(_BoundArgs) >= _Arity::value + 1
837		    : sizeof...(_BoundArgs) == _Arity::value + 1,
838		    "Wrong number of arguments for pointer-to-member");
839    };
840
841  // Trait type used to remove std::bind() from overload set via SFINAE
842  // when first argument has integer type, so that std::bind() will
843  // not be a better match than ::bind() from the BSD Sockets API.
844  template<typename _Tp, typename _Tp2 = typename decay<_Tp>::type>
845    using __is_socketlike = __or_<is_integral<_Tp2>, is_enum<_Tp2>>;
846
847  template<bool _SocketLike, typename _Func, typename... _BoundArgs>
848    struct _Bind_helper
849    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
850    {
851      typedef typename decay<_Func>::type __func_type;
852      typedef _Bind<__func_type(typename decay<_BoundArgs>::type...)> type;
853    };
854
855  // Partial specialization for is_socketlike == true, does not define
856  // nested type so std::bind() will not participate in overload resolution
857  // when the first argument might be a socket file descriptor.
858  template<typename _Func, typename... _BoundArgs>
859    struct _Bind_helper<true, _Func, _BoundArgs...>
860    { };
861
862  /**
863   *  @brief Function template for std::bind.
864   *  @ingroup binders
865   *  @since C++11
866   */
867  template<typename _Func, typename... _BoundArgs>
868    inline _GLIBCXX20_CONSTEXPR typename
869    _Bind_helper<__is_socketlike<_Func>::value, _Func, _BoundArgs...>::type
870    bind(_Func&& __f, _BoundArgs&&... __args)
871    {
872      typedef _Bind_helper<false, _Func, _BoundArgs...> __helper_type;
873      return typename __helper_type::type(std::forward<_Func>(__f),
874					  std::forward<_BoundArgs>(__args)...);
875    }
876
877  template<typename _Result, typename _Func, typename... _BoundArgs>
878    struct _Bindres_helper
879    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
880    {
881      typedef typename decay<_Func>::type __functor_type;
882      typedef _Bind_result<_Result,
883			   __functor_type(typename decay<_BoundArgs>::type...)>
884	type;
885    };
886
887  /**
888   *  @brief Function template for std::bind<R>.
889   *  @ingroup binders
890   *  @since C++11
891   */
892  template<typename _Result, typename _Func, typename... _BoundArgs>
893    inline _GLIBCXX20_CONSTEXPR
894    typename _Bindres_helper<_Result, _Func, _BoundArgs...>::type
895    bind(_Func&& __f, _BoundArgs&&... __args)
896    {
897      typedef _Bindres_helper<_Result, _Func, _BoundArgs...> __helper_type;
898      return typename __helper_type::type(std::forward<_Func>(__f),
899					  std::forward<_BoundArgs>(__args)...);
900    }
901
902#if __cplusplus > 201703L
903#define __cpp_lib_bind_front 201907L
904
905  template<typename _Fd, typename... _BoundArgs>
906    struct _Bind_front
907    {
908      static_assert(is_move_constructible_v<_Fd>);
909      static_assert((is_move_constructible_v<_BoundArgs> && ...));
910
911      // First parameter is to ensure this constructor is never used
912      // instead of the copy/move constructor.
913      template<typename _Fn, typename... _Args>
914	explicit constexpr
915	_Bind_front(int, _Fn&& __fn, _Args&&... __args)
916	noexcept(__and_<is_nothrow_constructible<_Fd, _Fn>,
917			is_nothrow_constructible<_BoundArgs, _Args>...>::value)
918	: _M_fd(std::forward<_Fn>(__fn)),
919	  _M_bound_args(std::forward<_Args>(__args)...)
920	{ static_assert(sizeof...(_Args) == sizeof...(_BoundArgs)); }
921
922      _Bind_front(const _Bind_front&) = default;
923      _Bind_front(_Bind_front&&) = default;
924      _Bind_front& operator=(const _Bind_front&) = default;
925      _Bind_front& operator=(_Bind_front&&) = default;
926      ~_Bind_front() = default;
927
928      template<typename... _CallArgs>
929	constexpr
930	invoke_result_t<_Fd&, _BoundArgs&..., _CallArgs...>
931	operator()(_CallArgs&&... __call_args) &
932	noexcept(is_nothrow_invocable_v<_Fd&, _BoundArgs&..., _CallArgs...>)
933	{
934	  return _S_call(*this, _BoundIndices(),
935	      std::forward<_CallArgs>(__call_args)...);
936	}
937
938      template<typename... _CallArgs>
939	constexpr
940	invoke_result_t<const _Fd&, const _BoundArgs&..., _CallArgs...>
941	operator()(_CallArgs&&... __call_args) const &
942	noexcept(is_nothrow_invocable_v<const _Fd&, const _BoundArgs&...,
943					_CallArgs...>)
944	{
945	  return _S_call(*this, _BoundIndices(),
946	      std::forward<_CallArgs>(__call_args)...);
947	}
948
949      template<typename... _CallArgs>
950	constexpr
951	invoke_result_t<_Fd, _BoundArgs..., _CallArgs...>
952	operator()(_CallArgs&&... __call_args) &&
953	noexcept(is_nothrow_invocable_v<_Fd, _BoundArgs..., _CallArgs...>)
954	{
955	  return _S_call(std::move(*this), _BoundIndices(),
956	      std::forward<_CallArgs>(__call_args)...);
957	}
958
959      template<typename... _CallArgs>
960	constexpr
961	invoke_result_t<const _Fd, const _BoundArgs..., _CallArgs...>
962	operator()(_CallArgs&&... __call_args) const &&
963	noexcept(is_nothrow_invocable_v<const _Fd, const _BoundArgs...,
964					_CallArgs...>)
965	{
966	  return _S_call(std::move(*this), _BoundIndices(),
967	      std::forward<_CallArgs>(__call_args)...);
968	}
969
970    private:
971      using _BoundIndices = index_sequence_for<_BoundArgs...>;
972
973      template<typename _Tp, size_t... _Ind, typename... _CallArgs>
974	static constexpr
975	decltype(auto)
976	_S_call(_Tp&& __g, index_sequence<_Ind...>, _CallArgs&&... __call_args)
977	{
978	  return std::invoke(std::forward<_Tp>(__g)._M_fd,
979	      std::get<_Ind>(std::forward<_Tp>(__g)._M_bound_args)...,
980	      std::forward<_CallArgs>(__call_args)...);
981	}
982
983      _Fd _M_fd;
984      std::tuple<_BoundArgs...> _M_bound_args;
985    };
986
987  template<typename _Fn, typename... _Args>
988    using _Bind_front_t
989      = _Bind_front<decay_t<_Fn>, decay_t<_Args>...>;
990
991  /** Create call wrapper by partial application of arguments to function.
992   *
993   * The result of `std::bind_front(f, args...)` is a function object that
994   * stores `f` and the bound arguments, `args...`. When that function
995   * object is invoked with `call_args...` it returns the result of calling
996   * `f(args..., call_args...)`.
997   *
998   *  @since C++20
999   */
1000  template<typename _Fn, typename... _Args>
1001    constexpr _Bind_front_t<_Fn, _Args...>
1002    bind_front(_Fn&& __fn, _Args&&... __args)
1003    noexcept(is_nothrow_constructible_v<_Bind_front_t<_Fn, _Args...>,
1004					int, _Fn, _Args...>)
1005    {
1006      return _Bind_front_t<_Fn, _Args...>(0, std::forward<_Fn>(__fn),
1007					  std::forward<_Args>(__args)...);
1008    }
1009#endif // C++20
1010
1011#if __cplusplus >= 201402L
1012  /// Generalized negator.
1013  template<typename _Fn>
1014    class _Not_fn
1015    {
1016      template<typename _Fn2, typename... _Args>
1017	using __inv_res_t = typename __invoke_result<_Fn2, _Args...>::type;
1018
1019      template<typename _Tp>
1020	static decltype(!std::declval<_Tp>())
1021	_S_not() noexcept(noexcept(!std::declval<_Tp>()));
1022
1023    public:
1024      template<typename _Fn2>
1025	constexpr
1026	_Not_fn(_Fn2&& __fn, int)
1027	: _M_fn(std::forward<_Fn2>(__fn)) { }
1028
1029      _Not_fn(const _Not_fn& __fn) = default;
1030      _Not_fn(_Not_fn&& __fn) = default;
1031      ~_Not_fn() = default;
1032
1033      // Macro to define operator() with given cv-qualifiers ref-qualifiers,
1034      // forwarding _M_fn and the function arguments with the same qualifiers,
1035      // and deducing the return type and exception-specification.
1036#define _GLIBCXX_NOT_FN_CALL_OP( _QUALS )				\
1037      template<typename... _Args>					\
1038	_GLIBCXX20_CONSTEXPR						\
1039	decltype(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>())		\
1040	operator()(_Args&&... __args) _QUALS				\
1041	noexcept(__is_nothrow_invocable<_Fn _QUALS, _Args...>::value	\
1042	    && noexcept(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>()))	\
1043	{								\
1044	  return !std::__invoke(std::forward< _Fn _QUALS >(_M_fn),	\
1045				std::forward<_Args>(__args)...);	\
1046	}
1047      _GLIBCXX_NOT_FN_CALL_OP( & )
1048      _GLIBCXX_NOT_FN_CALL_OP( const & )
1049      _GLIBCXX_NOT_FN_CALL_OP( && )
1050      _GLIBCXX_NOT_FN_CALL_OP( const && )
1051#undef _GLIBCXX_NOT_FN_CALL_OP
1052
1053    private:
1054      _Fn _M_fn;
1055    };
1056
1057  template<typename _Tp, typename _Pred>
1058    struct __is_byte_like : false_type { };
1059
1060  template<typename _Tp>
1061    struct __is_byte_like<_Tp, equal_to<_Tp>>
1062    : __bool_constant<sizeof(_Tp) == 1 && is_integral<_Tp>::value> { };
1063
1064  template<typename _Tp>
1065    struct __is_byte_like<_Tp, equal_to<void>>
1066    : __bool_constant<sizeof(_Tp) == 1 && is_integral<_Tp>::value> { };
1067
1068#if __cplusplus >= 201703L
1069  // Declare std::byte (full definition is in <cstddef>).
1070  enum class byte : unsigned char;
1071
1072  template<>
1073    struct __is_byte_like<byte, equal_to<byte>>
1074    : true_type { };
1075
1076  template<>
1077    struct __is_byte_like<byte, equal_to<void>>
1078    : true_type { };
1079
1080  // [func.not_fn] Function template not_fn
1081#define __cpp_lib_not_fn 201603L
1082  /** Wrap a function object to create one that negates its result.
1083   *
1084   * The function template `std::not_fn` creates a "forwarding call wrapper",
1085   * which is a function object that wraps another function object and
1086   * when called, forwards its arguments to the wrapped function object.
1087   *
1088   * The result of invoking the wrapper is the negation (using `!`) of
1089   * the wrapped function object.
1090   *
1091   *  @ingroup functors
1092   *  @since C++17
1093   */
1094  template<typename _Fn>
1095    _GLIBCXX20_CONSTEXPR
1096    inline auto
1097    not_fn(_Fn&& __fn)
1098    noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
1099    {
1100      return _Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
1101    }
1102
1103  // Searchers
1104#define __cpp_lib_boyer_moore_searcher 201603L
1105
1106  template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
1107    class default_searcher
1108    {
1109    public:
1110      _GLIBCXX20_CONSTEXPR
1111      default_searcher(_ForwardIterator1 __pat_first,
1112		       _ForwardIterator1 __pat_last,
1113		       _BinaryPredicate __pred = _BinaryPredicate())
1114      : _M_m(__pat_first, __pat_last, std::move(__pred))
1115      { }
1116
1117      template<typename _ForwardIterator2>
1118	_GLIBCXX20_CONSTEXPR
1119	pair<_ForwardIterator2, _ForwardIterator2>
1120	operator()(_ForwardIterator2 __first, _ForwardIterator2 __last) const
1121	{
1122	  _ForwardIterator2 __first_ret =
1123	    std::search(__first, __last, std::get<0>(_M_m), std::get<1>(_M_m),
1124			std::get<2>(_M_m));
1125	  auto __ret = std::make_pair(__first_ret, __first_ret);
1126	  if (__ret.first != __last)
1127	    std::advance(__ret.second, std::distance(std::get<0>(_M_m),
1128						     std::get<1>(_M_m)));
1129	  return __ret;
1130	}
1131
1132    private:
1133      tuple<_ForwardIterator1, _ForwardIterator1, _BinaryPredicate> _M_m;
1134    };
1135
1136  template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
1137    struct __boyer_moore_map_base
1138    {
1139      template<typename _RAIter>
1140	__boyer_moore_map_base(_RAIter __pat, size_t __patlen,
1141			       _Hash&& __hf, _Pred&& __pred)
1142	: _M_bad_char{ __patlen, std::move(__hf), std::move(__pred) }
1143	{
1144	  if (__patlen > 0)
1145	    for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
1146	      _M_bad_char[__pat[__i]] = __patlen - 1 - __i;
1147	}
1148
1149      using __diff_type = _Tp;
1150
1151      __diff_type
1152      _M_lookup(_Key __key, __diff_type __not_found) const
1153      {
1154	auto __iter = _M_bad_char.find(__key);
1155	if (__iter == _M_bad_char.end())
1156	  return __not_found;
1157	return __iter->second;
1158      }
1159
1160      _Pred
1161      _M_pred() const { return _M_bad_char.key_eq(); }
1162
1163      _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _Pred> _M_bad_char;
1164    };
1165
1166  template<typename _Tp, size_t _Len, typename _Pred>
1167    struct __boyer_moore_array_base
1168    {
1169      template<typename _RAIter, typename _Unused>
1170	__boyer_moore_array_base(_RAIter __pat, size_t __patlen,
1171				 _Unused&&, _Pred&& __pred)
1172	: _M_bad_char{ array<_Tp, _Len>{}, std::move(__pred) }
1173	{
1174	  std::get<0>(_M_bad_char).fill(__patlen);
1175	  if (__patlen > 0)
1176	    for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
1177	      {
1178		auto __ch = __pat[__i];
1179		using _UCh = make_unsigned_t<decltype(__ch)>;
1180		auto __uch = static_cast<_UCh>(__ch);
1181		std::get<0>(_M_bad_char)[__uch] = __patlen - 1 - __i;
1182	      }
1183	}
1184
1185      using __diff_type = _Tp;
1186
1187      template<typename _Key>
1188	__diff_type
1189	_M_lookup(_Key __key, __diff_type __not_found) const
1190	{
1191	  auto __ukey = static_cast<make_unsigned_t<_Key>>(__key);
1192	  if (__ukey >= _Len)
1193	    return __not_found;
1194	  return std::get<0>(_M_bad_char)[__ukey];
1195	}
1196
1197      const _Pred&
1198      _M_pred() const { return std::get<1>(_M_bad_char); }
1199
1200      tuple<array<_Tp, _Len>, _Pred> _M_bad_char;
1201    };
1202
1203  // Use __boyer_moore_array_base when pattern consists of narrow characters
1204  // (or std::byte) and uses std::equal_to as the predicate.
1205  template<typename _RAIter, typename _Hash, typename _Pred,
1206           typename _Val = typename iterator_traits<_RAIter>::value_type,
1207	   typename _Diff = typename iterator_traits<_RAIter>::difference_type>
1208    using __boyer_moore_base_t
1209      = __conditional_t<__is_byte_like<_Val, _Pred>::value,
1210			__boyer_moore_array_base<_Diff, 256, _Pred>,
1211			__boyer_moore_map_base<_Val, _Diff, _Hash, _Pred>>;
1212
1213  template<typename _RAIter, typename _Hash
1214	     = hash<typename iterator_traits<_RAIter>::value_type>,
1215	   typename _BinaryPredicate = equal_to<>>
1216    class boyer_moore_searcher
1217    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
1218    {
1219      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
1220      using typename _Base::__diff_type;
1221
1222    public:
1223      boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
1224			   _Hash __hf = _Hash(),
1225			   _BinaryPredicate __pred = _BinaryPredicate());
1226
1227      template<typename _RandomAccessIterator2>
1228        pair<_RandomAccessIterator2, _RandomAccessIterator2>
1229	operator()(_RandomAccessIterator2 __first,
1230		   _RandomAccessIterator2 __last) const;
1231
1232    private:
1233      bool
1234      _M_is_prefix(_RAIter __word, __diff_type __len,
1235		   __diff_type __pos)
1236      {
1237	const auto& __pred = this->_M_pred();
1238	__diff_type __suffixlen = __len - __pos;
1239	for (__diff_type __i = 0; __i < __suffixlen; ++__i)
1240	  if (!__pred(__word[__i], __word[__pos + __i]))
1241	    return false;
1242	return true;
1243      }
1244
1245      __diff_type
1246      _M_suffix_length(_RAIter __word, __diff_type __len,
1247		       __diff_type __pos)
1248      {
1249	const auto& __pred = this->_M_pred();
1250	__diff_type __i = 0;
1251	while (__pred(__word[__pos - __i], __word[__len - 1 - __i])
1252	       && __i < __pos)
1253	  {
1254	    ++__i;
1255	  }
1256	return __i;
1257      }
1258
1259      template<typename _Tp>
1260	__diff_type
1261	_M_bad_char_shift(_Tp __c) const
1262	{ return this->_M_lookup(__c, _M_pat_end - _M_pat); }
1263
1264      _RAIter _M_pat;
1265      _RAIter _M_pat_end;
1266      _GLIBCXX_STD_C::vector<__diff_type> _M_good_suffix;
1267    };
1268
1269  template<typename _RAIter, typename _Hash
1270	     = hash<typename iterator_traits<_RAIter>::value_type>,
1271	   typename _BinaryPredicate = equal_to<>>
1272    class boyer_moore_horspool_searcher
1273    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
1274    {
1275      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
1276      using typename _Base::__diff_type;
1277
1278    public:
1279      boyer_moore_horspool_searcher(_RAIter __pat,
1280				    _RAIter __pat_end,
1281				    _Hash __hf = _Hash(),
1282				    _BinaryPredicate __pred
1283				    = _BinaryPredicate())
1284      : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
1285	_M_pat(__pat), _M_pat_end(__pat_end)
1286      { }
1287
1288      template<typename _RandomAccessIterator2>
1289        pair<_RandomAccessIterator2, _RandomAccessIterator2>
1290	operator()(_RandomAccessIterator2 __first,
1291		   _RandomAccessIterator2 __last) const
1292	{
1293	  const auto& __pred = this->_M_pred();
1294	  auto __patlen = _M_pat_end - _M_pat;
1295	  if (__patlen == 0)
1296	    return std::make_pair(__first, __first);
1297	  auto __len = __last - __first;
1298	  while (__len >= __patlen)
1299	    {
1300	      for (auto __scan = __patlen - 1;
1301		   __pred(__first[__scan], _M_pat[__scan]); --__scan)
1302		if (__scan == 0)
1303		  return std::make_pair(__first, __first + __patlen);
1304	      auto __shift = _M_bad_char_shift(__first[__patlen - 1]);
1305	      __len -= __shift;
1306	      __first += __shift;
1307	    }
1308	  return std::make_pair(__last, __last);
1309	}
1310
1311    private:
1312      template<typename _Tp>
1313	__diff_type
1314	_M_bad_char_shift(_Tp __c) const
1315	{ return this->_M_lookup(__c, _M_pat_end - _M_pat); }
1316
1317      _RAIter _M_pat;
1318      _RAIter _M_pat_end;
1319    };
1320
1321  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
1322    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
1323    boyer_moore_searcher(_RAIter __pat, _RAIter __pat_end,
1324			 _Hash __hf, _BinaryPredicate __pred)
1325    : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
1326      _M_pat(__pat), _M_pat_end(__pat_end), _M_good_suffix(__pat_end - __pat)
1327    {
1328      auto __patlen = __pat_end - __pat;
1329      if (__patlen == 0)
1330	return;
1331      __diff_type __last_prefix = __patlen - 1;
1332      for (__diff_type __p = __patlen - 1; __p >= 0; --__p)
1333	{
1334	  if (_M_is_prefix(__pat, __patlen, __p + 1))
1335	    __last_prefix = __p + 1;
1336	  _M_good_suffix[__p] = __last_prefix + (__patlen - 1 - __p);
1337	}
1338      for (__diff_type __p = 0; __p < __patlen - 1; ++__p)
1339	{
1340	  auto __slen = _M_suffix_length(__pat, __patlen, __p);
1341	  auto __pos = __patlen - 1 - __slen;
1342	  if (!__pred(__pat[__p - __slen], __pat[__pos]))
1343	    _M_good_suffix[__pos] = __patlen - 1 - __p + __slen;
1344	}
1345    }
1346
1347  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
1348  template<typename _RandomAccessIterator2>
1349    pair<_RandomAccessIterator2, _RandomAccessIterator2>
1350    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
1351    operator()(_RandomAccessIterator2 __first,
1352	       _RandomAccessIterator2 __last) const
1353    {
1354      auto __patlen = _M_pat_end - _M_pat;
1355      if (__patlen == 0)
1356	return std::make_pair(__first, __first);
1357      const auto& __pred = this->_M_pred();
1358      __diff_type __i = __patlen - 1;
1359      auto __stringlen = __last - __first;
1360      while (__i < __stringlen)
1361	{
1362	  __diff_type __j = __patlen - 1;
1363	  while (__j >= 0 && __pred(__first[__i], _M_pat[__j]))
1364	    {
1365	      --__i;
1366	      --__j;
1367	    }
1368	  if (__j < 0)
1369	    {
1370	      const auto __match = __first + __i + 1;
1371	      return std::make_pair(__match, __match + __patlen);
1372	    }
1373	  __i += std::max(_M_bad_char_shift(__first[__i]),
1374			  _M_good_suffix[__j]);
1375	}
1376      return std::make_pair(__last, __last);
1377    }
1378
1379#endif // C++17
1380#endif // C++14
1381#endif // C++11
1382
1383_GLIBCXX_END_NAMESPACE_VERSION
1384} // namespace std
1385
1386#endif // _GLIBCXX_FUNCTIONAL
1387