libstdc++-v3/include/std/functional

   1 // <functional> -*- C++ -*-
   2
   3 // Copyright (C) 2001-2021 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
  71 #endif // C++11
  72
  73 namespace std _GLIBCXX_VISIBILITY(default)
  74 {
  75 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  76
  77   /** @brief The type of placeholder objects defined by libstdc++.
  78    *  @ingroup binders
  79    */
  80   template<int _Num> struct _Placeholder { };
  81
  82 #if __cplusplus >= 201103L
  83
  84 #if __cplusplus >= 201703L
  85 # define __cpp_lib_invoke 201411L
  86 # if __cplusplus > 201703L
  87 #  define __cpp_lib_constexpr_functional 201907L
  88 # endif
  89
  90   /// Invoke a callable object.
  91   template<typename _Callable, typename... _Args>
  92     inline _GLIBCXX20_CONSTEXPR invoke_result_t<_Callable, _Args...>
  93     invoke(_Callable&& __fn, _Args&&... __args)
  94     noexcept(is_nothrow_invocable_v<_Callable, _Args...>)
  95     {
  96       return std::__invoke(std::forward<_Callable>(__fn),
  97                            std::forward<_Args>(__args)...);
  98     }
  99
 100 #if __cplusplus > 202002L
 101 # define __cpp_lib_invoke_r 202106L
 102
 103   /// Invoke a callable object and convert the result to _Res.
 104   template<typename _Res, typename _Callable, typename... _Args>
 105     requires is_invocable_r_v<_Res, _Callable, _Args...>
 106     constexpr _Res
 107     invoke_r(_Callable&& __fn, _Args&&... __args)
 108     noexcept(is_nothrow_invocable_r_v<_Res, _Callable, _Args...>)
 109     {
 110       return std::__invoke_r<_Res>(std::forward<_Callable>(__fn),
 111                                    std::forward<_Args>(__args)...);
 112     }
 113 #endif // C++23
 114 #endif // C++17
 115
 116   template<typename _MemFunPtr,
 117            bool __is_mem_fn = is_member_function_pointer<_MemFunPtr>::value>
 118     class _Mem_fn_base
 119     : public _Mem_fn_traits<_MemFunPtr>::__maybe_type
 120     {
 121       using _Traits = _Mem_fn_traits<_MemFunPtr>;
 122
 123       using _Arity = typename _Traits::__arity;
 124       using _Varargs = typename _Traits::__vararg;
 125
 126       template<typename _Func, typename... _BoundArgs>
 127         friend struct _Bind_check_arity;
 128
 129       _MemFunPtr _M_pmf;
 130
 131     public:
 132
 133       using result_type = typename _Traits::__result_type;
 134
 135       explicit constexpr
 136       _Mem_fn_base(_MemFunPtr __pmf) noexcept : _M_pmf(__pmf) { }
 137
 138       template<typename... _Args>
 139         _GLIBCXX20_CONSTEXPR
 140         auto
 141         operator()(_Args&&... __args) const
 142         noexcept(noexcept(
 143               std::__invoke(_M_pmf, std::forward<_Args>(__args)...)))
 144         -> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
 145         { return std::__invoke(_M_pmf, std::forward<_Args>(__args)...); }
 146     };
 147
 148   // Partial specialization for member object pointers.
 149   template<typename _MemObjPtr>
 150     class _Mem_fn_base<_MemObjPtr, false>
 151     {
 152       using _Arity = integral_constant<size_t, 0>;
 153       using _Varargs = false_type;
 154
 155       template<typename _Func, typename... _BoundArgs>
 156         friend struct _Bind_check_arity;
 157
 158       _MemObjPtr _M_pm;
 159
 160     public:
 161       explicit constexpr
 162       _Mem_fn_base(_MemObjPtr __pm) noexcept : _M_pm(__pm) { }
 163
 164       template<typename _Tp>
 165         _GLIBCXX20_CONSTEXPR
 166         auto
 167         operator()(_Tp&& __obj) const
 168         noexcept(noexcept(std::__invoke(_M_pm, std::forward<_Tp>(__obj))))
 169         -> decltype(std::__invoke(_M_pm, std::forward<_Tp>(__obj)))
 170         { return std::__invoke(_M_pm, std::forward<_Tp>(__obj)); }
 171     };
 172
 173   template<typename _MemberPointer>
 174     struct _Mem_fn; // undefined
 175
 176   template<typename _Res, typename _Class>
 177     struct _Mem_fn<_Res _Class::*>
 178     : _Mem_fn_base<_Res _Class::*>
 179     {
 180       using _Mem_fn_base<_Res _Class::*>::_Mem_fn_base;
 181     };
 182
 183   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 184   // 2048.  Unnecessary mem_fn overloads
 185   /**
 186    *  @brief Returns a function object that forwards to the member
 187    *  pointer @a pm.
 188    *  @ingroup functors
 189    */
 190   template<typename _Tp, typename _Class>
 191     _GLIBCXX20_CONSTEXPR
 192     inline _Mem_fn<_Tp _Class::*>
 193     mem_fn(_Tp _Class::* __pm) noexcept
 194     {
 195       return _Mem_fn<_Tp _Class::*>(__pm);
 196     }
 197
 198   /**
 199    *  @brief Determines if the given type _Tp is a function object that
 200    *  should be treated as a subexpression when evaluating calls to
 201    *  function objects returned by bind().
 202    *
 203    *  C++11 [func.bind.isbind].
 204    *  @ingroup binders
 205    */
 206   template<typename _Tp>
 207     struct is_bind_expression
 208     : public false_type { };
 209
 210   /**
 211    *  @brief Determines if the given type _Tp is a placeholder in a
 212    *  bind() expression and, if so, which placeholder it is.
 213    *
 214    *  C++11 [func.bind.isplace].
 215    *  @ingroup binders
 216    */
 217   template<typename _Tp>
 218     struct is_placeholder
 219     : public integral_constant<int, 0>
 220     { };
 221
 222 #if __cplusplus > 201402L
 223   template <typename _Tp> inline constexpr bool is_bind_expression_v
 224     = is_bind_expression<_Tp>::value;
 225   template <typename _Tp> inline constexpr int is_placeholder_v
 226     = is_placeholder<_Tp>::value;
 227 #endif // C++17
 228
 229   /** @namespace std::placeholders
 230    *  @brief ISO C++ 2011 namespace for std::bind placeholders.
 231    *  @ingroup binders
 232    */
 233   namespace placeholders
 234   {
 235   /* Define a large number of placeholders. There is no way to
 236    * simplify this with variadic templates, because we're introducing
 237    * unique names for each.
 238    */
 239     extern const _Placeholder<1> _1;
 240     extern const _Placeholder<2> _2;
 241     extern const _Placeholder<3> _3;
 242     extern const _Placeholder<4> _4;
 243     extern const _Placeholder<5> _5;
 244     extern const _Placeholder<6> _6;
 245     extern const _Placeholder<7> _7;
 246     extern const _Placeholder<8> _8;
 247     extern const _Placeholder<9> _9;
 248     extern const _Placeholder<10> _10;
 249     extern const _Placeholder<11> _11;
 250     extern const _Placeholder<12> _12;
 251     extern const _Placeholder<13> _13;
 252     extern const _Placeholder<14> _14;
 253     extern const _Placeholder<15> _15;
 254     extern const _Placeholder<16> _16;
 255     extern const _Placeholder<17> _17;
 256     extern const _Placeholder<18> _18;
 257     extern const _Placeholder<19> _19;
 258     extern const _Placeholder<20> _20;
 259     extern const _Placeholder<21> _21;
 260     extern const _Placeholder<22> _22;
 261     extern const _Placeholder<23> _23;
 262     extern const _Placeholder<24> _24;
 263     extern const _Placeholder<25> _25;
 264     extern const _Placeholder<26> _26;
 265     extern const _Placeholder<27> _27;
 266     extern const _Placeholder<28> _28;
 267     extern const _Placeholder<29> _29;
 268   }
 269
 270   /**
 271    *  Partial specialization of is_placeholder that provides the placeholder
 272    *  number for the placeholder objects defined by libstdc++.
 273    *  @ingroup binders
 274    */
 275   template<int _Num>
 276     struct is_placeholder<_Placeholder<_Num> >
 277     : public integral_constant<int, _Num>
 278     { };
 279
 280   template<int _Num>
 281     struct is_placeholder<const _Placeholder<_Num> >
 282     : public integral_constant<int, _Num>
 283     { };
 284
 285
 286   // Like tuple_element_t but SFINAE-friendly.
 287   template<std::size_t __i, typename _Tuple>
 288     using _Safe_tuple_element_t
 289       = typename enable_if<(__i < tuple_size<_Tuple>::value),
 290                            tuple_element<__i, _Tuple>>::type::type;
 291
 292   /**
 293    *  Maps an argument to bind() into an actual argument to the bound
 294    *  function object [func.bind.bind]/10. Only the first parameter should
 295    *  be specified: the rest are used to determine among the various
 296    *  implementations. Note that, although this class is a function
 297    *  object, it isn't entirely normal because it takes only two
 298    *  parameters regardless of the number of parameters passed to the
 299    *  bind expression. The first parameter is the bound argument and
 300    *  the second parameter is a tuple containing references to the
 301    *  rest of the arguments.
 302    */
 303   template<typename _Arg,
 304            bool _IsBindExp = is_bind_expression<_Arg>::value,
 305            bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
 306     class _Mu;
 307
 308   /**
 309    *  If the argument is reference_wrapper<_Tp>, returns the
 310    *  underlying reference.
 311    *  C++11 [func.bind.bind] p10 bullet 1.
 312    */
 313   template<typename _Tp>
 314     class _Mu<reference_wrapper<_Tp>, false, false>
 315     {
 316     public:
 317       /* Note: This won't actually work for const volatile
 318        * reference_wrappers, because reference_wrapper::get() is const
 319        * but not volatile-qualified. This might be a defect in the TR.
 320        */
 321       template<typename _CVRef, typename _Tuple>
 322         _GLIBCXX20_CONSTEXPR
 323         _Tp&
 324         operator()(_CVRef& __arg, _Tuple&) const volatile
 325         { return __arg.get(); }
 326     };
 327
 328   /**
 329    *  If the argument is a bind expression, we invoke the underlying
 330    *  function object with the same cv-qualifiers as we are given and
 331    *  pass along all of our arguments (unwrapped).
 332    *  C++11 [func.bind.bind] p10 bullet 2.
 333    */
 334   template<typename _Arg>
 335     class _Mu<_Arg, true, false>
 336     {
 337     public:
 338       template<typename _CVArg, typename... _Args>
 339         _GLIBCXX20_CONSTEXPR
 340         auto
 341         operator()(_CVArg& __arg,
 342                    tuple<_Args...>& __tuple) const volatile
 343         -> decltype(__arg(declval<_Args>()...))
 344         {
 345           // Construct an index tuple and forward to __call
 346           typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
 347             _Indexes;
 348           return this->__call(__arg, __tuple, _Indexes());
 349         }
 350
 351     private:
 352       // Invokes the underlying function object __arg by unpacking all
 353       // of the arguments in the tuple.
 354       template<typename _CVArg, typename... _Args, std::size_t... _Indexes>
 355         _GLIBCXX20_CONSTEXPR
 356         auto
 357         __call(_CVArg& __arg, tuple<_Args...>& __tuple,
 358                const _Index_tuple<_Indexes...>&) const volatile
 359         -> decltype(__arg(declval<_Args>()...))
 360         {
 361           return __arg(std::get<_Indexes>(std::move(__tuple))...);
 362         }
 363     };
 364
 365   /**
 366    *  If the argument is a placeholder for the Nth argument, returns
 367    *  a reference to the Nth argument to the bind function object.
 368    *  C++11 [func.bind.bind] p10 bullet 3.
 369    */
 370   template<typename _Arg>
 371     class _Mu<_Arg, false, true>
 372     {
 373     public:
 374       template<typename _Tuple>
 375         _GLIBCXX20_CONSTEXPR
 376         _Safe_tuple_element_t<(is_placeholder<_Arg>::value - 1), _Tuple>&&
 377         operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
 378         {
 379           return
 380             ::std::get<(is_placeholder<_Arg>::value - 1)>(std::move(__tuple));
 381         }
 382     };
 383
 384   /**
 385    *  If the argument is just a value, returns a reference to that
 386    *  value. The cv-qualifiers on the reference are determined by the caller.
 387    *  C++11 [func.bind.bind] p10 bullet 4.
 388    */
 389   template<typename _Arg>
 390     class _Mu<_Arg, false, false>
 391     {
 392     public:
 393       template<typename _CVArg, typename _Tuple>
 394         _GLIBCXX20_CONSTEXPR
 395         _CVArg&&
 396         operator()(_CVArg&& __arg, _Tuple&) const volatile
 397         { return std::forward<_CVArg>(__arg); }
 398     };
 399
 400   // std::get<I> for volatile-qualified tuples
 401   template<std::size_t _Ind, typename... _Tp>
 402     inline auto
 403     __volget(volatile tuple<_Tp...>& __tuple)
 404     -> __tuple_element_t<_Ind, tuple<_Tp...>> volatile&
 405     { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
 406
 407   // std::get<I> for const-volatile-qualified tuples
 408   template<std::size_t _Ind, typename... _Tp>
 409     inline auto
 410     __volget(const volatile tuple<_Tp...>& __tuple)
 411     -> __tuple_element_t<_Ind, tuple<_Tp...>> const volatile&
 412     { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
 413
 414   /// Type of the function object returned from bind().
 415   template<typename _Signature>
 416     class _Bind;
 417
 418    template<typename _Functor, typename... _Bound_args>
 419     class _Bind<_Functor(_Bound_args...)>
 420     : public _Weak_result_type<_Functor>
 421     {
 422       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
 423         _Bound_indexes;
 424
 425       _Functor _M_f;
 426       tuple<_Bound_args...> _M_bound_args;
 427
 428       // Call unqualified
 429       template<typename _Result, typename... _Args, std::size_t... _Indexes>
 430         _GLIBCXX20_CONSTEXPR
 431         _Result
 432         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
 433         {
 434           return std::__invoke(_M_f,
 435               _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
 436               );
 437         }
 438
 439       // Call as const
 440       template<typename _Result, typename... _Args, std::size_t... _Indexes>
 441         _GLIBCXX20_CONSTEXPR
 442         _Result
 443         __call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
 444         {
 445           return std::__invoke(_M_f,
 446               _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
 447               );
 448         }
 449
 450       // Call as volatile
 451       template<typename _Result, typename... _Args, std::size_t... _Indexes>
 452         _Result
 453         __call_v(tuple<_Args...>&& __args,
 454                  _Index_tuple<_Indexes...>) volatile
 455         {
 456           return std::__invoke(_M_f,
 457               _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
 458               );
 459         }
 460
 461       // Call as const volatile
 462       template<typename _Result, typename... _Args, std::size_t... _Indexes>
 463         _Result
 464         __call_c_v(tuple<_Args...>&& __args,
 465                    _Index_tuple<_Indexes...>) const volatile
 466         {
 467           return std::__invoke(_M_f,
 468               _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
 469               );
 470         }
 471
 472       template<typename _BoundArg, typename _CallArgs>
 473         using _Mu_type = decltype(
 474             _Mu<typename remove_cv<_BoundArg>::type>()(
 475               std::declval<_BoundArg&>(), std::declval<_CallArgs&>()) );
 476
 477       template<typename _Fn, typename _CallArgs, typename... _BArgs>
 478         using _Res_type_impl
 479           = typename result_of< _Fn&(_Mu_type<_BArgs, _CallArgs>&&...) >::type;
 480
 481       template<typename _CallArgs>
 482         using _Res_type = _Res_type_impl<_Functor, _CallArgs, _Bound_args...>;
 483
 484       template<typename _CallArgs>
 485         using __dependent = typename
 486           enable_if<bool(tuple_size<_CallArgs>::value+1), _Functor>::type;
 487
 488       template<typename _CallArgs, template<class> class __cv_quals>
 489         using _Res_type_cv = _Res_type_impl<
 490           typename __cv_quals<__dependent<_CallArgs>>::type,
 491           _CallArgs,
 492           typename __cv_quals<_Bound_args>::type...>;
 493
 494      public:
 495       template<typename... _Args>
 496         explicit _GLIBCXX20_CONSTEXPR
 497         _Bind(const _Functor& __f, _Args&&... __args)
 498         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
 499         { }
 500
 501       template<typename... _Args>
 502         explicit _GLIBCXX20_CONSTEXPR
 503         _Bind(_Functor&& __f, _Args&&... __args)
 504         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
 505         { }
 506
 507       _Bind(const _Bind&) = default;
 508       _Bind(_Bind&&) = default;
 509
 510       // Call unqualified
 511       template<typename... _Args,
 512                typename _Result = _Res_type<tuple<_Args...>>>
 513         _GLIBCXX20_CONSTEXPR
 514         _Result
 515         operator()(_Args&&... __args)
 516         {
 517           return this->__call<_Result>(
 518               std::forward_as_tuple(std::forward<_Args>(__args)...),
 519               _Bound_indexes());
 520         }
 521
 522       // Call as const
 523       template<typename... _Args,
 524                typename _Result = _Res_type_cv<tuple<_Args...>, add_const>>
 525         _GLIBCXX20_CONSTEXPR
 526         _Result
 527         operator()(_Args&&... __args) const
 528         {
 529           return this->__call_c<_Result>(
 530               std::forward_as_tuple(std::forward<_Args>(__args)...),
 531               _Bound_indexes());
 532         }
 533
 534 #if __cplusplus > 201402L
 535 # define _GLIBCXX_DEPR_BIND \
 536       [[deprecated("std::bind does not support volatile in C++17")]]
 537 #else
 538 # define _GLIBCXX_DEPR_BIND
 539 #endif
 540       // Call as volatile
 541       template<typename... _Args,
 542                typename _Result = _Res_type_cv<tuple<_Args...>, add_volatile>>
 543         _GLIBCXX_DEPR_BIND
 544         _Result
 545         operator()(_Args&&... __args) volatile
 546         {
 547           return this->__call_v<_Result>(
 548               std::forward_as_tuple(std::forward<_Args>(__args)...),
 549               _Bound_indexes());
 550         }
 551
 552       // Call as const volatile
 553       template<typename... _Args,
 554                typename _Result = _Res_type_cv<tuple<_Args...>, add_cv>>
 555         _GLIBCXX_DEPR_BIND
 556         _Result
 557         operator()(_Args&&... __args) const volatile
 558         {
 559           return this->__call_c_v<_Result>(
 560               std::forward_as_tuple(std::forward<_Args>(__args)...),
 561               _Bound_indexes());
 562         }
 563     };
 564
 565   /// Type of the function object returned from bind<R>().
 566   template<typename _Result, typename _Signature>
 567     class _Bind_result;
 568
 569   template<typename _Result, typename _Functor, typename... _Bound_args>
 570     class _Bind_result<_Result, _Functor(_Bound_args...)>
 571     {
 572       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
 573         _Bound_indexes;
 574
 575       _Functor _M_f;
 576       tuple<_Bound_args...> _M_bound_args;
 577
 578       // Call unqualified
 579       template<typename _Res, typename... _Args, std::size_t... _Indexes>
 580         _GLIBCXX20_CONSTEXPR
 581         _Res
 582         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
 583         {
 584           return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
 585                       (std::get<_Indexes>(_M_bound_args), __args)...);
 586         }
 587
 588       // Call as const
 589       template<typename _Res, typename... _Args, std::size_t... _Indexes>
 590         _GLIBCXX20_CONSTEXPR
 591         _Res
 592         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
 593         {
 594           return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
 595                       (std::get<_Indexes>(_M_bound_args), __args)...);
 596         }
 597
 598       // Call as volatile
 599       template<typename _Res, typename... _Args, std::size_t... _Indexes>
 600         _GLIBCXX20_CONSTEXPR
 601         _Res
 602         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) volatile
 603         {
 604           return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
 605                       (__volget<_Indexes>(_M_bound_args), __args)...);
 606         }
 607
 608       // Call as const volatile
 609       template<typename _Res, typename... _Args, std::size_t... _Indexes>
 610         _GLIBCXX20_CONSTEXPR
 611         _Res
 612         __call(tuple<_Args...>&& __args,
 613                _Index_tuple<_Indexes...>) const volatile
 614         {
 615           return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
 616                       (__volget<_Indexes>(_M_bound_args), __args)...);
 617         }
 618
 619     public:
 620       typedef _Result result_type;
 621
 622       template<typename... _Args>
 623         explicit _GLIBCXX20_CONSTEXPR
 624         _Bind_result(const _Functor& __f, _Args&&... __args)
 625         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
 626         { }
 627
 628       template<typename... _Args>
 629         explicit _GLIBCXX20_CONSTEXPR
 630         _Bind_result(_Functor&& __f, _Args&&... __args)
 631         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
 632         { }
 633
 634       _Bind_result(const _Bind_result&) = default;
 635       _Bind_result(_Bind_result&&) = default;
 636
 637       // Call unqualified
 638       template<typename... _Args>
 639         _GLIBCXX20_CONSTEXPR
 640         result_type
 641         operator()(_Args&&... __args)
 642         {
 643           return this->__call<_Result>(
 644               std::forward_as_tuple(std::forward<_Args>(__args)...),
 645               _Bound_indexes());
 646         }
 647
 648       // Call as const
 649       template<typename... _Args>
 650         _GLIBCXX20_CONSTEXPR
 651         result_type
 652         operator()(_Args&&... __args) const
 653         {
 654           return this->__call<_Result>(
 655               std::forward_as_tuple(std::forward<_Args>(__args)...),
 656               _Bound_indexes());
 657         }
 658
 659       // Call as volatile
 660       template<typename... _Args>
 661         _GLIBCXX_DEPR_BIND
 662         result_type
 663         operator()(_Args&&... __args) volatile
 664         {
 665           return this->__call<_Result>(
 666               std::forward_as_tuple(std::forward<_Args>(__args)...),
 667               _Bound_indexes());
 668         }
 669
 670       // Call as const volatile
 671       template<typename... _Args>
 672         _GLIBCXX_DEPR_BIND
 673         result_type
 674         operator()(_Args&&... __args) const volatile
 675         {
 676           return this->__call<_Result>(
 677               std::forward_as_tuple(std::forward<_Args>(__args)...),
 678               _Bound_indexes());
 679         }
 680     };
 681 #undef _GLIBCXX_DEPR_BIND
 682
 683   /**
 684    *  @brief Class template _Bind is always a bind expression.
 685    *  @ingroup binders
 686    */
 687   template<typename _Signature>
 688     struct is_bind_expression<_Bind<_Signature> >
 689     : public true_type { };
 690
 691   /**
 692    *  @brief Class template _Bind is always a bind expression.
 693    *  @ingroup binders
 694    */
 695   template<typename _Signature>
 696     struct is_bind_expression<const _Bind<_Signature> >
 697     : public true_type { };
 698
 699   /**
 700    *  @brief Class template _Bind is always a bind expression.
 701    *  @ingroup binders
 702    */
 703   template<typename _Signature>
 704     struct is_bind_expression<volatile _Bind<_Signature> >
 705     : public true_type { };
 706
 707   /**
 708    *  @brief Class template _Bind is always a bind expression.
 709    *  @ingroup binders
 710    */
 711   template<typename _Signature>
 712     struct is_bind_expression<const volatile _Bind<_Signature>>
 713     : public true_type { };
 714
 715   /**
 716    *  @brief Class template _Bind_result is always a bind expression.
 717    *  @ingroup binders
 718    */
 719   template<typename _Result, typename _Signature>
 720     struct is_bind_expression<_Bind_result<_Result, _Signature>>
 721     : public true_type { };
 722
 723   /**
 724    *  @brief Class template _Bind_result is always a bind expression.
 725    *  @ingroup binders
 726    */
 727   template<typename _Result, typename _Signature>
 728     struct is_bind_expression<const _Bind_result<_Result, _Signature>>
 729     : public true_type { };
 730
 731   /**
 732    *  @brief Class template _Bind_result is always a bind expression.
 733    *  @ingroup binders
 734    */
 735   template<typename _Result, typename _Signature>
 736     struct is_bind_expression<volatile _Bind_result<_Result, _Signature>>
 737     : public true_type { };
 738
 739   /**
 740    *  @brief Class template _Bind_result is always a bind expression.
 741    *  @ingroup binders
 742    */
 743   template<typename _Result, typename _Signature>
 744     struct is_bind_expression<const volatile _Bind_result<_Result, _Signature>>
 745     : public true_type { };
 746
 747   template<typename _Func, typename... _BoundArgs>
 748     struct _Bind_check_arity { };
 749
 750   template<typename _Ret, typename... _Args, typename... _BoundArgs>
 751     struct _Bind_check_arity<_Ret (*)(_Args...), _BoundArgs...>
 752     {
 753       static_assert(sizeof...(_BoundArgs) == sizeof...(_Args),
 754                    "Wrong number of arguments for function");
 755     };
 756
 757   template<typename _Ret, typename... _Args, typename... _BoundArgs>
 758     struct _Bind_check_arity<_Ret (*)(_Args......), _BoundArgs...>
 759     {
 760       static_assert(sizeof...(_BoundArgs) >= sizeof...(_Args),
 761                    "Wrong number of arguments for function");
 762     };
 763
 764   template<typename _Tp, typename _Class, typename... _BoundArgs>
 765     struct _Bind_check_arity<_Tp _Class::*, _BoundArgs...>
 766     {
 767       using _Arity = typename _Mem_fn<_Tp _Class::*>::_Arity;
 768       using _Varargs = typename _Mem_fn<_Tp _Class::*>::_Varargs;
 769       static_assert(_Varargs::value
 770                     ? sizeof...(_BoundArgs) >= _Arity::value + 1
 771                     : sizeof...(_BoundArgs) == _Arity::value + 1,
 772                     "Wrong number of arguments for pointer-to-member");
 773     };
 774
 775   // Trait type used to remove std::bind() from overload set via SFINAE
 776   // when first argument has integer type, so that std::bind() will
 777   // not be a better match than ::bind() from the BSD Sockets API.
 778   template<typename _Tp, typename _Tp2 = typename decay<_Tp>::type>
 779     using __is_socketlike = __or_<is_integral<_Tp2>, is_enum<_Tp2>>;
 780
 781   template<bool _SocketLike, typename _Func, typename... _BoundArgs>
 782     struct _Bind_helper
 783     : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
 784     {
 785       typedef typename decay<_Func>::type __func_type;
 786       typedef _Bind<__func_type(typename decay<_BoundArgs>::type...)> type;
 787     };
 788
 789   // Partial specialization for is_socketlike == true, does not define
 790   // nested type so std::bind() will not participate in overload resolution
 791   // when the first argument might be a socket file descriptor.
 792   template<typename _Func, typename... _BoundArgs>
 793     struct _Bind_helper<true, _Func, _BoundArgs...>
 794     { };
 795
 796   /**
 797    *  @brief Function template for std::bind.
 798    *  @ingroup binders
 799    */
 800   template<typename _Func, typename... _BoundArgs>
 801     inline _GLIBCXX20_CONSTEXPR typename
 802     _Bind_helper<__is_socketlike<_Func>::value, _Func, _BoundArgs...>::type
 803     bind(_Func&& __f, _BoundArgs&&... __args)
 804     {
 805       typedef _Bind_helper<false, _Func, _BoundArgs...> __helper_type;
 806       return typename __helper_type::type(std::forward<_Func>(__f),
 807                                           std::forward<_BoundArgs>(__args)...);
 808     }
 809
 810   template<typename _Result, typename _Func, typename... _BoundArgs>
 811     struct _Bindres_helper
 812     : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
 813     {
 814       typedef typename decay<_Func>::type __functor_type;
 815       typedef _Bind_result<_Result,
 816                            __functor_type(typename decay<_BoundArgs>::type...)>
 817         type;
 818     };
 819
 820   /**
 821    *  @brief Function template for std::bind<R>.
 822    *  @ingroup binders
 823    */
 824   template<typename _Result, typename _Func, typename... _BoundArgs>
 825     inline _GLIBCXX20_CONSTEXPR
 826     typename _Bindres_helper<_Result, _Func, _BoundArgs...>::type
 827     bind(_Func&& __f, _BoundArgs&&... __args)
 828     {
 829       typedef _Bindres_helper<_Result, _Func, _BoundArgs...> __helper_type;
 830       return typename __helper_type::type(std::forward<_Func>(__f),
 831                                           std::forward<_BoundArgs>(__args)...);
 832     }
 833
 834 #if __cplusplus > 201703L
 835 #define __cpp_lib_bind_front 201907L
 836
 837   template<typename _Fd, typename... _BoundArgs>
 838     struct _Bind_front
 839     {
 840       static_assert(is_move_constructible_v<_Fd>);
 841       static_assert((is_move_constructible_v<_BoundArgs> && ...));
 842
 843       // First parameter is to ensure this constructor is never used
 844       // instead of the copy/move constructor.
 845       template<typename _Fn, typename... _Args>
 846         explicit constexpr
 847         _Bind_front(int, _Fn&& __fn, _Args&&... __args)
 848         noexcept(__and_<is_nothrow_constructible<_Fd, _Fn>,
 849                         is_nothrow_constructible<_BoundArgs, _Args>...>::value)
 850         : _M_fd(std::forward<_Fn>(__fn)),
 851           _M_bound_args(std::forward<_Args>(__args)...)
 852         { static_assert(sizeof...(_Args) == sizeof...(_BoundArgs)); }
 853
 854       _Bind_front(const _Bind_front&) = default;
 855       _Bind_front(_Bind_front&&) = default;
 856       _Bind_front& operator=(const _Bind_front&) = default;
 857       _Bind_front& operator=(_Bind_front&&) = default;
 858       ~_Bind_front() = default;
 859
 860       template<typename... _CallArgs>
 861         constexpr
 862         invoke_result_t<_Fd&, _BoundArgs&..., _CallArgs...>
 863         operator()(_CallArgs&&... __call_args) &
 864         noexcept(is_nothrow_invocable_v<_Fd&, _BoundArgs&..., _CallArgs...>)
 865         {
 866           return _S_call(*this, _BoundIndices(),
 867               std::forward<_CallArgs>(__call_args)...);
 868         }
 869
 870       template<typename... _CallArgs>
 871         constexpr
 872         invoke_result_t<const _Fd&, const _BoundArgs&..., _CallArgs...>
 873         operator()(_CallArgs&&... __call_args) const &
 874         noexcept(is_nothrow_invocable_v<const _Fd&, const _BoundArgs&...,
 875                                         _CallArgs...>)
 876         {
 877           return _S_call(*this, _BoundIndices(),
 878               std::forward<_CallArgs>(__call_args)...);
 879         }
 880
 881       template<typename... _CallArgs>
 882         constexpr
 883         invoke_result_t<_Fd, _BoundArgs..., _CallArgs...>
 884         operator()(_CallArgs&&... __call_args) &&
 885         noexcept(is_nothrow_invocable_v<_Fd, _BoundArgs..., _CallArgs...>)
 886         {
 887           return _S_call(std::move(*this), _BoundIndices(),
 888               std::forward<_CallArgs>(__call_args)...);
 889         }
 890
 891       template<typename... _CallArgs>
 892         constexpr
 893         invoke_result_t<const _Fd, const _BoundArgs..., _CallArgs...>
 894         operator()(_CallArgs&&... __call_args) const &&
 895         noexcept(is_nothrow_invocable_v<const _Fd, const _BoundArgs...,
 896                                         _CallArgs...>)
 897         {
 898           return _S_call(std::move(*this), _BoundIndices(),
 899               std::forward<_CallArgs>(__call_args)...);
 900         }
 901
 902     private:
 903       using _BoundIndices = index_sequence_for<_BoundArgs...>;
 904
 905       template<typename _Tp, size_t... _Ind, typename... _CallArgs>
 906         static constexpr
 907         decltype(auto)
 908         _S_call(_Tp&& __g, index_sequence<_Ind...>, _CallArgs&&... __call_args)
 909         {
 910           return std::invoke(std::forward<_Tp>(__g)._M_fd,
 911               std::get<_Ind>(std::forward<_Tp>(__g)._M_bound_args)...,
 912               std::forward<_CallArgs>(__call_args)...);
 913         }
 914
 915       _Fd _M_fd;
 916       std::tuple<_BoundArgs...> _M_bound_args;
 917     };
 918
 919   template<typename _Fn, typename... _Args>
 920     using _Bind_front_t
 921       = _Bind_front<decay_t<_Fn>, decay_t<_Args>...>;
 922
 923   template<typename _Fn, typename... _Args>
 924     constexpr _Bind_front_t<_Fn, _Args...>
 925     bind_front(_Fn&& __fn, _Args&&... __args)
 926     noexcept(is_nothrow_constructible_v<_Bind_front_t<_Fn, _Args...>,
 927                                         int, _Fn, _Args...>)
 928     {
 929       return _Bind_front_t<_Fn, _Args...>(0, std::forward<_Fn>(__fn),
 930                                           std::forward<_Args>(__args)...);
 931     }
 932 #endif
 933
 934 #if __cplusplus >= 201402L
 935   /// Generalized negator.
 936   template<typename _Fn>
 937     class _Not_fn
 938     {
 939       template<typename _Fn2, typename... _Args>
 940         using __inv_res_t = typename __invoke_result<_Fn2, _Args...>::type;
 941
 942       template<typename _Tp>
 943         static decltype(!std::declval<_Tp>())
 944         _S_not() noexcept(noexcept(!std::declval<_Tp>()));
 945
 946     public:
 947       template<typename _Fn2>
 948         constexpr
 949         _Not_fn(_Fn2&& __fn, int)
 950         : _M_fn(std::forward<_Fn2>(__fn)) { }
 951
 952       _Not_fn(const _Not_fn& __fn) = default;
 953       _Not_fn(_Not_fn&& __fn) = default;
 954       ~_Not_fn() = default;
 955
 956       // Macro to define operator() with given cv-qualifiers ref-qualifiers,
 957       // forwarding _M_fn and the function arguments with the same qualifiers,
 958       // and deducing the return type and exception-specification.
 959 #define _GLIBCXX_NOT_FN_CALL_OP( _QUALS )                               \
 960       template<typename... _Args>                                       \
 961         _GLIBCXX20_CONSTEXPR                                            \
 962         decltype(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>())           \
 963         operator()(_Args&&... __args) _QUALS                            \
 964         noexcept(__is_nothrow_invocable<_Fn _QUALS, _Args...>::value    \
 965             && noexcept(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>()))   \
 966         {                                                               \
 967           return !std::__invoke(std::forward< _Fn _QUALS >(_M_fn),      \
 968                                 std::forward<_Args>(__args)...);        \
 969         }
 970       _GLIBCXX_NOT_FN_CALL_OP( & )
 971       _GLIBCXX_NOT_FN_CALL_OP( const & )
 972       _GLIBCXX_NOT_FN_CALL_OP( && )
 973       _GLIBCXX_NOT_FN_CALL_OP( const && )
 974 #undef _GLIBCXX_NOT_FN_CALL_OP
 975
 976     private:
 977       _Fn _M_fn;
 978     };
 979
 980   template<typename _Tp, typename _Pred>
 981     struct __is_byte_like : false_type { };
 982
 983   template<typename _Tp>
 984     struct __is_byte_like<_Tp, equal_to<_Tp>>
 985     : __bool_constant<sizeof(_Tp) == 1 && is_integral<_Tp>::value> { };
 986
 987   template<typename _Tp>
 988     struct __is_byte_like<_Tp, equal_to<void>>
 989     : __bool_constant<sizeof(_Tp) == 1 && is_integral<_Tp>::value> { };
 990
 991 #if __cplusplus >= 201703L
 992   // Declare std::byte (full definition is in <cstddef>).
 993   enum class byte : unsigned char;
 994
 995   template<>
 996     struct __is_byte_like<byte, equal_to<byte>>
 997     : true_type { };
 998
 999   template<>
1000     struct __is_byte_like<byte, equal_to<void>>
1001     : true_type { };
1002
1003 #define __cpp_lib_not_fn 201603
1004   /// [func.not_fn] Function template not_fn
1005   template<typename _Fn>
1006     _GLIBCXX20_CONSTEXPR
1007     inline auto
1008     not_fn(_Fn&& __fn)
1009     noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
1010     {
1011       return _Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
1012     }
1013
1014   // Searchers
1015 #define __cpp_lib_boyer_moore_searcher 201603
1016
1017   template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
1018     class default_searcher
1019     {
1020     public:
1021       _GLIBCXX20_CONSTEXPR
1022       default_searcher(_ForwardIterator1 __pat_first,
1023                        _ForwardIterator1 __pat_last,
1024                        _BinaryPredicate __pred = _BinaryPredicate())
1025       : _M_m(__pat_first, __pat_last, std::move(__pred))
1026       { }
1027
1028       template<typename _ForwardIterator2>
1029         _GLIBCXX20_CONSTEXPR
1030         pair<_ForwardIterator2, _ForwardIterator2>
1031         operator()(_ForwardIterator2 __first, _ForwardIterator2 __last) const
1032         {
1033           _ForwardIterator2 __first_ret =
1034             std::search(__first, __last, std::get<0>(_M_m), std::get<1>(_M_m),
1035                         std::get<2>(_M_m));
1036           auto __ret = std::make_pair(__first_ret, __first_ret);
1037           if (__ret.first != __last)
1038             std::advance(__ret.second, std::distance(std::get<0>(_M_m),
1039                                                      std::get<1>(_M_m)));
1040           return __ret;
1041         }
1042
1043     private:
1044       tuple<_ForwardIterator1, _ForwardIterator1, _BinaryPredicate> _M_m;
1045     };
1046
1047   template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
1048     struct __boyer_moore_map_base
1049     {
1050       template<typename _RAIter>
1051         __boyer_moore_map_base(_RAIter __pat, size_t __patlen,
1052                                _Hash&& __hf, _Pred&& __pred)
1053         : _M_bad_char{ __patlen, std::move(__hf), std::move(__pred) }
1054         {
1055           if (__patlen > 0)
1056             for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
1057               _M_bad_char[__pat[__i]] = __patlen - 1 - __i;
1058         }
1059
1060       using __diff_type = _Tp;
1061
1062       __diff_type
1063       _M_lookup(_Key __key, __diff_type __not_found) const
1064       {
1065         auto __iter = _M_bad_char.find(__key);
1066         if (__iter == _M_bad_char.end())
1067           return __not_found;
1068         return __iter->second;
1069       }
1070
1071       _Pred
1072       _M_pred() const { return _M_bad_char.key_eq(); }
1073
1074       _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _Pred> _M_bad_char;
1075     };
1076
1077   template<typename _Tp, size_t _Len, typename _Pred>
1078     struct __boyer_moore_array_base
1079     {
1080       template<typename _RAIter, typename _Unused>
1081         __boyer_moore_array_base(_RAIter __pat, size_t __patlen,
1082                                  _Unused&&, _Pred&& __pred)
1083         : _M_bad_char{ array<_Tp, _Len>{}, std::move(__pred) }
1084         {
1085           std::get<0>(_M_bad_char).fill(__patlen);
1086           if (__patlen > 0)
1087             for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
1088               {
1089                 auto __ch = __pat[__i];
1090                 using _UCh = make_unsigned_t<decltype(__ch)>;
1091                 auto __uch = static_cast<_UCh>(__ch);
1092                 std::get<0>(_M_bad_char)[__uch] = __patlen - 1 - __i;
1093               }
1094         }
1095
1096       using __diff_type = _Tp;
1097
1098       template<typename _Key>
1099         __diff_type
1100         _M_lookup(_Key __key, __diff_type __not_found) const
1101         {
1102           auto __ukey = static_cast<make_unsigned_t<_Key>>(__key);
1103           if (__ukey >= _Len)
1104             return __not_found;
1105           return std::get<0>(_M_bad_char)[__ukey];
1106         }
1107
1108       const _Pred&
1109       _M_pred() const { return std::get<1>(_M_bad_char); }
1110
1111       tuple<array<_Tp, _Len>, _Pred> _M_bad_char;
1112     };
1113
1114   // Use __boyer_moore_array_base when pattern consists of narrow characters
1115   // (or std::byte) and uses std::equal_to as the predicate.
1116   template<typename _RAIter, typename _Hash, typename _Pred,
1117            typename _Val = typename iterator_traits<_RAIter>::value_type,
1118            typename _Diff = typename iterator_traits<_RAIter>::difference_type>
1119     using __boyer_moore_base_t
1120       = __conditional_t<__is_byte_like<_Val, _Pred>::value,
1121                         __boyer_moore_array_base<_Diff, 256, _Pred>,
1122                         __boyer_moore_map_base<_Val, _Diff, _Hash, _Pred>>;
1123
1124   template<typename _RAIter, typename _Hash
1125              = hash<typename iterator_traits<_RAIter>::value_type>,
1126            typename _BinaryPredicate = equal_to<>>
1127     class boyer_moore_searcher
1128     : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
1129     {
1130       using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
1131       using typename _Base::__diff_type;
1132
1133     public:
1134       boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
1135                            _Hash __hf = _Hash(),
1136                            _BinaryPredicate __pred = _BinaryPredicate());
1137
1138       template<typename _RandomAccessIterator2>
1139         pair<_RandomAccessIterator2, _RandomAccessIterator2>
1140         operator()(_RandomAccessIterator2 __first,
1141                    _RandomAccessIterator2 __last) const;
1142
1143     private:
1144       bool
1145       _M_is_prefix(_RAIter __word, __diff_type __len,
1146                    __diff_type __pos)
1147       {
1148         const auto& __pred = this->_M_pred();
1149         __diff_type __suffixlen = __len - __pos;
1150         for (__diff_type __i = 0; __i < __suffixlen; ++__i)
1151           if (!__pred(__word[__i], __word[__pos + __i]))
1152             return false;
1153         return true;
1154       }
1155
1156       __diff_type
1157       _M_suffix_length(_RAIter __word, __diff_type __len,
1158                        __diff_type __pos)
1159       {
1160         const auto& __pred = this->_M_pred();
1161         __diff_type __i = 0;
1162         while (__pred(__word[__pos - __i], __word[__len - 1 - __i])
1163                && __i < __pos)
1164           {
1165             ++__i;
1166           }
1167         return __i;
1168       }
1169
1170       template<typename _Tp>
1171         __diff_type
1172         _M_bad_char_shift(_Tp __c) const
1173         { return this->_M_lookup(__c, _M_pat_end - _M_pat); }
1174
1175       _RAIter _M_pat;
1176       _RAIter _M_pat_end;
1177       _GLIBCXX_STD_C::vector<__diff_type> _M_good_suffix;
1178     };
1179
1180   template<typename _RAIter, typename _Hash
1181              = hash<typename iterator_traits<_RAIter>::value_type>,
1182            typename _BinaryPredicate = equal_to<>>
1183     class boyer_moore_horspool_searcher
1184     : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
1185     {
1186       using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
1187       using typename _Base::__diff_type;
1188
1189     public:
1190       boyer_moore_horspool_searcher(_RAIter __pat,
1191                                     _RAIter __pat_end,
1192                                     _Hash __hf = _Hash(),
1193                                     _BinaryPredicate __pred
1194                                     = _BinaryPredicate())
1195       : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
1196         _M_pat(__pat), _M_pat_end(__pat_end)
1197       { }
1198
1199       template<typename _RandomAccessIterator2>
1200         pair<_RandomAccessIterator2, _RandomAccessIterator2>
1201         operator()(_RandomAccessIterator2 __first,
1202                    _RandomAccessIterator2 __last) const
1203         {
1204           const auto& __pred = this->_M_pred();
1205           auto __patlen = _M_pat_end - _M_pat;
1206           if (__patlen == 0)
1207             return std::make_pair(__first, __first);
1208           auto __len = __last - __first;
1209           while (__len >= __patlen)
1210             {
1211               for (auto __scan = __patlen - 1;
1212                    __pred(__first[__scan], _M_pat[__scan]); --__scan)
1213                 if (__scan == 0)
1214                   return std::make_pair(__first, __first + __patlen);
1215               auto __shift = _M_bad_char_shift(__first[__patlen - 1]);
1216               __len -= __shift;
1217               __first += __shift;
1218             }
1219           return std::make_pair(__last, __last);
1220         }
1221
1222     private:
1223       template<typename _Tp>
1224         __diff_type
1225         _M_bad_char_shift(_Tp __c) const
1226         { return this->_M_lookup(__c, _M_pat_end - _M_pat); }
1227
1228       _RAIter _M_pat;
1229       _RAIter _M_pat_end;
1230     };
1231
1232   template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
1233     boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
1234     boyer_moore_searcher(_RAIter __pat, _RAIter __pat_end,
1235                          _Hash __hf, _BinaryPredicate __pred)
1236     : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
1237       _M_pat(__pat), _M_pat_end(__pat_end), _M_good_suffix(__pat_end - __pat)
1238     {
1239       auto __patlen = __pat_end - __pat;
1240       if (__patlen == 0)
1241         return;
1242       __diff_type __last_prefix = __patlen - 1;
1243       for (__diff_type __p = __patlen - 1; __p >= 0; --__p)
1244         {
1245           if (_M_is_prefix(__pat, __patlen, __p + 1))
1246             __last_prefix = __p + 1;
1247           _M_good_suffix[__p] = __last_prefix + (__patlen - 1 - __p);
1248         }
1249       for (__diff_type __p = 0; __p < __patlen - 1; ++__p)
1250         {
1251           auto __slen = _M_suffix_length(__pat, __patlen, __p);
1252           auto __pos = __patlen - 1 - __slen;
1253           if (!__pred(__pat[__p - __slen], __pat[__pos]))
1254             _M_good_suffix[__pos] = __patlen - 1 - __p + __slen;
1255         }
1256     }
1257
1258   template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
1259   template<typename _RandomAccessIterator2>
1260     pair<_RandomAccessIterator2, _RandomAccessIterator2>
1261     boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
1262     operator()(_RandomAccessIterator2 __first,
1263                _RandomAccessIterator2 __last) const
1264     {
1265       auto __patlen = _M_pat_end - _M_pat;
1266       if (__patlen == 0)
1267         return std::make_pair(__first, __first);
1268       const auto& __pred = this->_M_pred();
1269       __diff_type __i = __patlen - 1;
1270       auto __stringlen = __last - __first;
1271       while (__i < __stringlen)
1272         {
1273           __diff_type __j = __patlen - 1;
1274           while (__j >= 0 && __pred(__first[__i], _M_pat[__j]))
1275             {
1276               --__i;
1277               --__j;
1278             }
1279           if (__j < 0)
1280             {
1281               const auto __match = __first + __i + 1;
1282               return std::make_pair(__match, __match + __patlen);
1283             }
1284           __i += std::max(_M_bad_char_shift(__first[__i]),
1285                           _M_good_suffix[__j]);
1286         }
1287       return std::make_pair(__last, __last);
1288     }
1289
1290 #endif // C++17
1291 #endif // C++14
1292 #endif // C++11
1293
1294 _GLIBCXX_END_NAMESPACE_VERSION
1295 } // namespace std
1296
1297 #endif // _GLIBCXX_FUNCTIONAL