libstdc++-v3/include/std/functional

   1 // <functional> -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /*
  27  * Copyright (c) 1997
  28  * Silicon Graphics Computer Systems, Inc.
  29  *
  30  * Permission to use, copy, modify, distribute and sell this software
  31  * and its documentation for any purpose is hereby granted without fee,
  32  * provided that the above copyright notice appear in all copies and
  33  * that both that copyright notice and this permission notice appear
  34  * in supporting documentation.  Silicon Graphics makes no
  35  * representations about the suitability of this software for any
  36  * purpose.  It is provided "as is" without express or implied warranty.
  37  *
  38  */
  39
  40 /** @file include/functional
  41  *  This is a Standard C++ Library header.
  42  */
  43
  44 #ifndef _GLIBCXX_FUNCTIONAL
  45 #define _GLIBCXX_FUNCTIONAL 1
  46
  47 #pragma GCC system_header
  48
  49 #include <bits/c++config.h>
  50 #include <bits/stl_function.h>
  51
  52 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  53
  54 #include <typeinfo>
  55 #include <new>
  56 #include <tuple>
  57 #include <type_traits>
  58 #include <bits/functexcept.h>
  59 #include <bits/functional_hash.h>
  60
  61 namespace std
  62 {
  63 _GLIBCXX_HAS_NESTED_TYPE(result_type)
  64
  65   /// If we have found a result_type, extract it.
  66   template<bool _Has_result_type, typename _Functor>
  67     struct _Maybe_get_result_type
  68     { };
  69
  70   template<typename _Functor>
  71     struct _Maybe_get_result_type<true, _Functor>
  72     { typedef typename _Functor::result_type result_type; };
  73
  74   /**
  75    *  Base class for any function object that has a weak result type, as
  76    *  defined in 3.3/3 of TR1.
  77   */
  78   template<typename _Functor>
  79     struct _Weak_result_type_impl
  80     : _Maybe_get_result_type<__has_result_type<_Functor>::value, _Functor>
  81     { };
  82
  83   /// Retrieve the result type for a function type.
  84   template<typename _Res, typename... _ArgTypes>
  85     struct _Weak_result_type_impl<_Res(_ArgTypes...)>
  86     { typedef _Res result_type; };
  87
  88   template<typename _Res, typename... _ArgTypes>
  89     struct _Weak_result_type_impl<_Res(_ArgTypes......)>
  90     { typedef _Res result_type; };
  91
  92   template<typename _Res, typename... _ArgTypes>
  93     struct _Weak_result_type_impl<_Res(_ArgTypes...) const>
  94     { typedef _Res result_type; };
  95
  96   template<typename _Res, typename... _ArgTypes>
  97     struct _Weak_result_type_impl<_Res(_ArgTypes......) const>
  98     { typedef _Res result_type; };
  99
 100   template<typename _Res, typename... _ArgTypes>
 101     struct _Weak_result_type_impl<_Res(_ArgTypes...) volatile>
 102     { typedef _Res result_type; };
 103
 104   template<typename _Res, typename... _ArgTypes>
 105     struct _Weak_result_type_impl<_Res(_ArgTypes......) volatile>
 106     { typedef _Res result_type; };
 107
 108   template<typename _Res, typename... _ArgTypes>
 109     struct _Weak_result_type_impl<_Res(_ArgTypes...) const volatile>
 110     { typedef _Res result_type; };
 111
 112   template<typename _Res, typename... _ArgTypes>
 113     struct _Weak_result_type_impl<_Res(_ArgTypes......) const volatile>
 114     { typedef _Res result_type; };
 115
 116   /// Retrieve the result type for a function reference.
 117   template<typename _Res, typename... _ArgTypes>
 118     struct _Weak_result_type_impl<_Res(&)(_ArgTypes...)>
 119     { typedef _Res result_type; };
 120
 121   template<typename _Res, typename... _ArgTypes>
 122     struct _Weak_result_type_impl<_Res(&)(_ArgTypes......)>
 123     { typedef _Res result_type; };
 124
 125   /// Retrieve the result type for a function pointer.
 126   template<typename _Res, typename... _ArgTypes>
 127     struct _Weak_result_type_impl<_Res(*)(_ArgTypes...)>
 128     { typedef _Res result_type; };
 129
 130   template<typename _Res, typename... _ArgTypes>
 131     struct _Weak_result_type_impl<_Res(*)(_ArgTypes......)>
 132     { typedef _Res result_type; };
 133
 134   /// Retrieve result type for a member function pointer.
 135   template<typename _Res, typename _Class, typename... _ArgTypes>
 136     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)>
 137     { typedef _Res result_type; };
 138
 139   template<typename _Res, typename _Class, typename... _ArgTypes>
 140     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)>
 141     { typedef _Res result_type; };
 142
 143   /// Retrieve result type for a const member function pointer.
 144   template<typename _Res, typename _Class, typename... _ArgTypes>
 145     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) const>
 146     { typedef _Res result_type; };
 147
 148   template<typename _Res, typename _Class, typename... _ArgTypes>
 149     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) const>
 150     { typedef _Res result_type; };
 151
 152   /// Retrieve result type for a volatile member function pointer.
 153   template<typename _Res, typename _Class, typename... _ArgTypes>
 154     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) volatile>
 155     { typedef _Res result_type; };
 156
 157   template<typename _Res, typename _Class, typename... _ArgTypes>
 158     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) volatile>
 159     { typedef _Res result_type; };
 160
 161   /// Retrieve result type for a const volatile member function pointer.
 162   template<typename _Res, typename _Class, typename... _ArgTypes>
 163     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)
 164                                   const volatile>
 165     { typedef _Res result_type; };
 166
 167   template<typename _Res, typename _Class, typename... _ArgTypes>
 168     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)
 169                                   const volatile>
 170     { typedef _Res result_type; };
 171
 172   /**
 173    *  Strip top-level cv-qualifiers from the function object and let
 174    *  _Weak_result_type_impl perform the real work.
 175   */
 176   template<typename _Functor>
 177     struct _Weak_result_type
 178     : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
 179     { };
 180
 181   /// Determines if the type _Tp derives from unary_function.
 182   template<typename _Tp>
 183     struct _Derives_from_unary_function : __sfinae_types
 184     {
 185     private:
 186       template<typename _T1, typename _Res>
 187         static __one __test(const volatile unary_function<_T1, _Res>*);
 188
 189       // It's tempting to change "..." to const volatile void*, but
 190       // that fails when _Tp is a function type.
 191       static __two __test(...);
 192
 193     public:
 194       static const bool value = sizeof(__test((_Tp*)0)) == 1;
 195     };
 196
 197   /// Determines if the type _Tp derives from binary_function.
 198   template<typename _Tp>
 199     struct _Derives_from_binary_function : __sfinae_types
 200     {
 201     private:
 202       template<typename _T1, typename _T2, typename _Res>
 203         static __one __test(const volatile binary_function<_T1, _T2, _Res>*);
 204
 205       // It's tempting to change "..." to const volatile void*, but
 206       // that fails when _Tp is a function type.
 207       static __two __test(...);
 208
 209     public:
 210       static const bool value = sizeof(__test((_Tp*)0)) == 1;
 211     };
 212
 213   /// Turns a function type into a function pointer type
 214   template<typename _Tp, bool _IsFunctionType = is_function<_Tp>::value>
 215     struct _Function_to_function_pointer
 216     {
 217       typedef _Tp type;
 218     };
 219
 220   template<typename _Tp>
 221     struct _Function_to_function_pointer<_Tp, true>
 222     {
 223       typedef _Tp* type;
 224     };
 225
 226   /**
 227    * Invoke a function object, which may be either a member pointer or a
 228    * function object. The first parameter will tell which.
 229    */
 230   template<typename _Functor, typename... _Args>
 231     inline
 232     typename enable_if<
 233              (!is_member_pointer<_Functor>::value
 234               && !is_function<_Functor>::value
 235               && !is_function<typename remove_pointer<_Functor>::type>::value),
 236              typename result_of<_Functor(_Args...)>::type
 237            >::type
 238     __invoke(_Functor& __f, _Args&&... __args)
 239     {
 240       return __f(std::forward<_Args>(__args)...);
 241     }
 242
 243   // To pick up function references (that will become function pointers)
 244   template<typename _Functor, typename... _Args>
 245     inline
 246     typename enable_if<
 247              (is_pointer<_Functor>::value
 248               && is_function<typename remove_pointer<_Functor>::type>::value),
 249              typename result_of<_Functor(_Args...)>::type
 250            >::type
 251     __invoke(_Functor __f, _Args&&... __args)
 252     {
 253       return __f(std::forward<_Args>(__args)...);
 254     }
 255
 256   /**
 257    *  Knowing which of unary_function and binary_function _Tp derives
 258    *  from, derives from the same and ensures that reference_wrapper
 259    *  will have a weak result type. See cases below.
 260    */
 261   template<bool _Unary, bool _Binary, typename _Tp>
 262     struct _Reference_wrapper_base_impl;
 263
 264   // Not a unary_function or binary_function, so try a weak result type.
 265   template<typename _Tp>
 266     struct _Reference_wrapper_base_impl<false, false, _Tp>
 267     : _Weak_result_type<_Tp>
 268     { };
 269
 270   // unary_function but not binary_function
 271   template<typename _Tp>
 272     struct _Reference_wrapper_base_impl<true, false, _Tp>
 273     : unary_function<typename _Tp::argument_type,
 274                      typename _Tp::result_type>
 275     { };
 276
 277   // binary_function but not unary_function
 278   template<typename _Tp>
 279     struct _Reference_wrapper_base_impl<false, true, _Tp>
 280     : binary_function<typename _Tp::first_argument_type,
 281                       typename _Tp::second_argument_type,
 282                       typename _Tp::result_type>
 283     { };
 284
 285   // Both unary_function and binary_function. Import result_type to
 286   // avoid conflicts.
 287    template<typename _Tp>
 288     struct _Reference_wrapper_base_impl<true, true, _Tp>
 289     : unary_function<typename _Tp::argument_type,
 290                      typename _Tp::result_type>,
 291       binary_function<typename _Tp::first_argument_type,
 292                       typename _Tp::second_argument_type,
 293                       typename _Tp::result_type>
 294     {
 295       typedef typename _Tp::result_type result_type;
 296     };
 297
 298   /**
 299    *  Derives from unary_function or binary_function when it
 300    *  can. Specializations handle all of the easy cases. The primary
 301    *  template determines what to do with a class type, which may
 302    *  derive from both unary_function and binary_function.
 303   */
 304   template<typename _Tp>
 305     struct _Reference_wrapper_base
 306     : _Reference_wrapper_base_impl<
 307       _Derives_from_unary_function<_Tp>::value,
 308       _Derives_from_binary_function<_Tp>::value,
 309       _Tp>
 310     { };
 311
 312   // - a function type (unary)
 313   template<typename _Res, typename _T1>
 314     struct _Reference_wrapper_base<_Res(_T1)>
 315     : unary_function<_T1, _Res>
 316     { };
 317
 318   template<typename _Res, typename _T1>
 319     struct _Reference_wrapper_base<_Res(_T1) const>
 320     : unary_function<_T1, _Res>
 321     { };
 322
 323   template<typename _Res, typename _T1>
 324     struct _Reference_wrapper_base<_Res(_T1) volatile>
 325     : unary_function<_T1, _Res>
 326     { };
 327
 328   template<typename _Res, typename _T1>
 329     struct _Reference_wrapper_base<_Res(_T1) const volatile>
 330     : unary_function<_T1, _Res>
 331     { };
 332
 333   // - a function type (binary)
 334   template<typename _Res, typename _T1, typename _T2>
 335     struct _Reference_wrapper_base<_Res(_T1, _T2)>
 336     : binary_function<_T1, _T2, _Res>
 337     { };
 338
 339   template<typename _Res, typename _T1, typename _T2>
 340     struct _Reference_wrapper_base<_Res(_T1, _T2) const>
 341     : binary_function<_T1, _T2, _Res>
 342     { };
 343
 344   template<typename _Res, typename _T1, typename _T2>
 345     struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
 346     : binary_function<_T1, _T2, _Res>
 347     { };
 348
 349   template<typename _Res, typename _T1, typename _T2>
 350     struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
 351     : binary_function<_T1, _T2, _Res>
 352     { };
 353
 354   // - a function pointer type (unary)
 355   template<typename _Res, typename _T1>
 356     struct _Reference_wrapper_base<_Res(*)(_T1)>
 357     : unary_function<_T1, _Res>
 358     { };
 359
 360   // - a function pointer type (binary)
 361   template<typename _Res, typename _T1, typename _T2>
 362     struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
 363     : binary_function<_T1, _T2, _Res>
 364     { };
 365
 366   // - a pointer to member function type (unary, no qualifiers)
 367   template<typename _Res, typename _T1>
 368     struct _Reference_wrapper_base<_Res (_T1::*)()>
 369     : unary_function<_T1*, _Res>
 370     { };
 371
 372   // - a pointer to member function type (binary, no qualifiers)
 373   template<typename _Res, typename _T1, typename _T2>
 374     struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
 375     : binary_function<_T1*, _T2, _Res>
 376     { };
 377
 378   // - a pointer to member function type (unary, const)
 379   template<typename _Res, typename _T1>
 380     struct _Reference_wrapper_base<_Res (_T1::*)() const>
 381     : unary_function<const _T1*, _Res>
 382     { };
 383
 384   // - a pointer to member function type (binary, const)
 385   template<typename _Res, typename _T1, typename _T2>
 386     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
 387     : binary_function<const _T1*, _T2, _Res>
 388     { };
 389
 390   // - a pointer to member function type (unary, volatile)
 391   template<typename _Res, typename _T1>
 392     struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
 393     : unary_function<volatile _T1*, _Res>
 394     { };
 395
 396   // - a pointer to member function type (binary, volatile)
 397   template<typename _Res, typename _T1, typename _T2>
 398     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
 399     : binary_function<volatile _T1*, _T2, _Res>
 400     { };
 401
 402   // - a pointer to member function type (unary, const volatile)
 403   template<typename _Res, typename _T1>
 404     struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
 405     : unary_function<const volatile _T1*, _Res>
 406     { };
 407
 408   // - a pointer to member function type (binary, const volatile)
 409   template<typename _Res, typename _T1, typename _T2>
 410     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
 411     : binary_function<const volatile _T1*, _T2, _Res>
 412     { };
 413
 414   /**
 415    *  @brief Primary class template for reference_wrapper.
 416    *  @ingroup functors
 417    *  @{
 418    */
 419   template<typename _Tp>
 420     class reference_wrapper
 421     : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
 422     {
 423       // If _Tp is a function type, we can't form result_of<_Tp(...)>,
 424       // so turn it into a function pointer type.
 425       typedef typename _Function_to_function_pointer<_Tp>::type
 426         _M_func_type;
 427
 428       _Tp* _M_data;
 429     public:
 430       typedef _Tp type;
 431
 432       reference_wrapper(_Tp& __indata)
 433       : _M_data(std::__addressof(__indata))
 434       { }
 435
 436       reference_wrapper(_Tp&&) = delete;
 437
 438       reference_wrapper(const reference_wrapper<_Tp>& __inref):
 439       _M_data(__inref._M_data)
 440       { }
 441
 442       reference_wrapper&
 443       operator=(const reference_wrapper<_Tp>& __inref)
 444       {
 445         _M_data = __inref._M_data;
 446         return *this;
 447       }
 448
 449       operator _Tp&() const
 450       { return this->get(); }
 451
 452       _Tp&
 453       get() const
 454       { return *_M_data; }
 455
 456       template<typename... _Args>
 457         typename result_of<_M_func_type(_Args...)>::type
 458         operator()(_Args&&... __args) const
 459         {
 460           return __invoke(get(), std::forward<_Args>(__args)...);
 461         }
 462     };
 463
 464
 465   /// Denotes a reference should be taken to a variable.
 466   template<typename _Tp>
 467     inline reference_wrapper<_Tp>
 468     ref(_Tp& __t)
 469     { return reference_wrapper<_Tp>(__t); }
 470
 471   /// Denotes a const reference should be taken to a variable.
 472   template<typename _Tp>
 473     inline reference_wrapper<const _Tp>
 474     cref(const _Tp& __t)
 475     { return reference_wrapper<const _Tp>(__t); }
 476
 477   /// Partial specialization.
 478   template<typename _Tp>
 479     inline reference_wrapper<_Tp>
 480     ref(reference_wrapper<_Tp> __t)
 481     { return ref(__t.get()); }
 482
 483   /// Partial specialization.
 484   template<typename _Tp>
 485     inline reference_wrapper<const _Tp>
 486     cref(reference_wrapper<_Tp> __t)
 487     { return cref(__t.get()); }
 488
 489   // @} group functors
 490
 491   template<typename _MemberPointer>
 492     class _Mem_fn;
 493
 494   /**
 495    * Derives from @c unary_function or @c binary_function, or perhaps
 496    * nothing, depending on the number of arguments provided. The
 497    * primary template is the basis case, which derives nothing.
 498    */
 499   template<typename _Res, typename... _ArgTypes>
 500     struct _Maybe_unary_or_binary_function { };
 501
 502   /// Derives from @c unary_function, as appropriate.
 503   template<typename _Res, typename _T1>
 504     struct _Maybe_unary_or_binary_function<_Res, _T1>
 505     : std::unary_function<_T1, _Res> { };
 506
 507   /// Derives from @c binary_function, as appropriate.
 508   template<typename _Res, typename _T1, typename _T2>
 509     struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
 510     : std::binary_function<_T1, _T2, _Res> { };
 511
 512   /// Implementation of @c mem_fn for member function pointers.
 513   template<typename _Res, typename _Class, typename... _ArgTypes>
 514     class _Mem_fn<_Res (_Class::*)(_ArgTypes...)>
 515     : public _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>
 516     {
 517       typedef _Res (_Class::*_Functor)(_ArgTypes...);
 518
 519       template<typename _Tp>
 520         _Res
 521         _M_call(_Tp& __object, const volatile _Class *,
 522                 _ArgTypes... __args) const
 523         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 524
 525       template<typename _Tp>
 526         _Res
 527         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 528         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 529
 530     public:
 531       typedef _Res result_type;
 532
 533       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 534
 535       // Handle objects
 536       _Res
 537       operator()(_Class& __object, _ArgTypes... __args) const
 538       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 539
 540       // Handle pointers
 541       _Res
 542       operator()(_Class* __object, _ArgTypes... __args) const
 543       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 544
 545       // Handle smart pointers, references and pointers to derived
 546       template<typename _Tp>
 547         _Res
 548         operator()(_Tp& __object, _ArgTypes... __args) const
 549         {
 550           return _M_call(__object, &__object,
 551               std::forward<_ArgTypes>(__args)...);
 552         }
 553
 554     private:
 555       _Functor __pmf;
 556     };
 557
 558   /// Implementation of @c mem_fn for const member function pointers.
 559   template<typename _Res, typename _Class, typename... _ArgTypes>
 560     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const>
 561     : public _Maybe_unary_or_binary_function<_Res, const _Class*,
 562                                              _ArgTypes...>
 563     {
 564       typedef _Res (_Class::*_Functor)(_ArgTypes...) const;
 565
 566       template<typename _Tp>
 567         _Res
 568         _M_call(_Tp& __object, const volatile _Class *,
 569                 _ArgTypes... __args) const
 570         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 571
 572       template<typename _Tp>
 573         _Res
 574         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 575         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 576
 577     public:
 578       typedef _Res result_type;
 579
 580       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 581
 582       // Handle objects
 583       _Res
 584       operator()(const _Class& __object, _ArgTypes... __args) const
 585       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 586
 587       // Handle pointers
 588       _Res
 589       operator()(const _Class* __object, _ArgTypes... __args) const
 590       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 591
 592       // Handle smart pointers, references and pointers to derived
 593       template<typename _Tp>
 594         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 595         {
 596           return _M_call(__object, &__object,
 597               std::forward<_ArgTypes>(__args)...);
 598         }
 599
 600     private:
 601       _Functor __pmf;
 602     };
 603
 604   /// Implementation of @c mem_fn for volatile member function pointers.
 605   template<typename _Res, typename _Class, typename... _ArgTypes>
 606     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) volatile>
 607     : public _Maybe_unary_or_binary_function<_Res, volatile _Class*,
 608                                              _ArgTypes...>
 609     {
 610       typedef _Res (_Class::*_Functor)(_ArgTypes...) volatile;
 611
 612       template<typename _Tp>
 613         _Res
 614         _M_call(_Tp& __object, const volatile _Class *,
 615                 _ArgTypes... __args) const
 616         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 617
 618       template<typename _Tp>
 619         _Res
 620         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 621         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 622
 623     public:
 624       typedef _Res result_type;
 625
 626       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 627
 628       // Handle objects
 629       _Res
 630       operator()(volatile _Class& __object, _ArgTypes... __args) const
 631       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 632
 633       // Handle pointers
 634       _Res
 635       operator()(volatile _Class* __object, _ArgTypes... __args) const
 636       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 637
 638       // Handle smart pointers, references and pointers to derived
 639       template<typename _Tp>
 640         _Res
 641         operator()(_Tp& __object, _ArgTypes... __args) const
 642         {
 643           return _M_call(__object, &__object,
 644               std::forward<_ArgTypes>(__args)...);
 645         }
 646
 647     private:
 648       _Functor __pmf;
 649     };
 650
 651   /// Implementation of @c mem_fn for const volatile member function pointers.
 652   template<typename _Res, typename _Class, typename... _ArgTypes>
 653     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const volatile>
 654     : public _Maybe_unary_or_binary_function<_Res, const volatile _Class*,
 655                                              _ArgTypes...>
 656     {
 657       typedef _Res (_Class::*_Functor)(_ArgTypes...) const volatile;
 658
 659       template<typename _Tp>
 660         _Res
 661         _M_call(_Tp& __object, const volatile _Class *,
 662                 _ArgTypes... __args) const
 663         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 664
 665       template<typename _Tp>
 666         _Res
 667         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 668         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 669
 670     public:
 671       typedef _Res result_type;
 672
 673       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 674
 675       // Handle objects
 676       _Res
 677       operator()(const volatile _Class& __object, _ArgTypes... __args) const
 678       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 679
 680       // Handle pointers
 681       _Res
 682       operator()(const volatile _Class* __object, _ArgTypes... __args) const
 683       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 684
 685       // Handle smart pointers, references and pointers to derived
 686       template<typename _Tp>
 687         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 688         {
 689           return _M_call(__object, &__object,
 690               std::forward<_ArgTypes>(__args)...);
 691         }
 692
 693     private:
 694       _Functor __pmf;
 695     };
 696
 697
 698   template<typename _Tp, bool>
 699     struct _Mem_fn_const_or_non
 700     {
 701       typedef const _Tp& type;
 702     };
 703
 704   template<typename _Tp>
 705     struct _Mem_fn_const_or_non<_Tp, false>
 706     {
 707       typedef _Tp& type;
 708     };
 709
 710   template<typename _Res, typename _Class>
 711     class _Mem_fn<_Res _Class::*>
 712     {
 713       // This bit of genius is due to Peter Dimov, improved slightly by
 714       // Douglas Gregor.
 715       template<typename _Tp>
 716         _Res&
 717         _M_call(_Tp& __object, _Class *) const
 718         { return __object.*__pm; }
 719
 720       template<typename _Tp, typename _Up>
 721         _Res&
 722         _M_call(_Tp& __object, _Up * const *) const
 723         { return (*__object).*__pm; }
 724
 725       template<typename _Tp, typename _Up>
 726         const _Res&
 727         _M_call(_Tp& __object, const _Up * const *) const
 728         { return (*__object).*__pm; }
 729
 730       template<typename _Tp>
 731         const _Res&
 732         _M_call(_Tp& __object, const _Class *) const
 733         { return __object.*__pm; }
 734
 735       template<typename _Tp>
 736         const _Res&
 737         _M_call(_Tp& __ptr, const volatile void*) const
 738         { return (*__ptr).*__pm; }
 739
 740       template<typename _Tp> static _Tp& __get_ref();
 741
 742       template<typename _Tp>
 743         static __sfinae_types::__one __check_const(_Tp&, _Class*);
 744       template<typename _Tp, typename _Up>
 745         static __sfinae_types::__one __check_const(_Tp&, _Up * const *);
 746       template<typename _Tp, typename _Up>
 747         static __sfinae_types::__two __check_const(_Tp&, const _Up * const *);
 748       template<typename _Tp>
 749         static __sfinae_types::__two __check_const(_Tp&, const _Class*);
 750       template<typename _Tp>
 751         static __sfinae_types::__two __check_const(_Tp&, const volatile void*);
 752
 753     public:
 754       template<typename _Tp>
 755         struct _Result_type
 756         : _Mem_fn_const_or_non<_Res,
 757           (sizeof(__sfinae_types::__two)
 758            == sizeof(__check_const<_Tp>(__get_ref<_Tp>(), (_Tp*)0)))>
 759         { };
 760
 761       template<typename _Signature>
 762         struct result;
 763
 764       template<typename _CVMem, typename _Tp>
 765         struct result<_CVMem(_Tp)>
 766         : public _Result_type<_Tp> { };
 767
 768       template<typename _CVMem, typename _Tp>
 769         struct result<_CVMem(_Tp&)>
 770         : public _Result_type<_Tp> { };
 771
 772       explicit
 773       _Mem_fn(_Res _Class::*__pm) : __pm(__pm) { }
 774
 775       // Handle objects
 776       _Res&
 777       operator()(_Class& __object) const
 778       { return __object.*__pm; }
 779
 780       const _Res&
 781       operator()(const _Class& __object) const
 782       { return __object.*__pm; }
 783
 784       // Handle pointers
 785       _Res&
 786       operator()(_Class* __object) const
 787       { return __object->*__pm; }
 788
 789       const _Res&
 790       operator()(const _Class* __object) const
 791       { return __object->*__pm; }
 792
 793       // Handle smart pointers and derived
 794       template<typename _Tp>
 795         typename _Result_type<_Tp>::type
 796         operator()(_Tp& __unknown) const
 797         { return _M_call(__unknown, &__unknown); }
 798
 799     private:
 800       _Res _Class::*__pm;
 801     };
 802
 803   /**
 804    *  @brief Returns a function object that forwards to the member
 805    *  pointer @a pm.
 806    *  @ingroup functors
 807    */
 808   template<typename _Tp, typename _Class>
 809     inline _Mem_fn<_Tp _Class::*>
 810     mem_fn(_Tp _Class::* __pm)
 811     {
 812       return _Mem_fn<_Tp _Class::*>(__pm);
 813     }
 814
 815   /**
 816    *  @brief Determines if the given type _Tp is a function object
 817    *  should be treated as a subexpression when evaluating calls to
 818    *  function objects returned by bind(). [TR1 3.6.1]
 819    *  @ingroup binders
 820    */
 821   template<typename _Tp>
 822     struct is_bind_expression
 823     : public false_type { };
 824
 825   /**
 826    *  @brief Determines if the given type _Tp is a placeholder in a
 827    *  bind() expression and, if so, which placeholder it is. [TR1 3.6.2]
 828    *  @ingroup binders
 829    */
 830   template<typename _Tp>
 831     struct is_placeholder
 832     : public integral_constant<int, 0>
 833     { };
 834
 835   /// The type of placeholder objects defined by libstdc++.
 836   template<int _Num> struct _Placeholder { };
 837
 838   /** @namespace std::placeholders
 839    *  @brief ISO C++ 0x entities sub namespace for functional.
 840    *  @ingroup binders
 841    *
 842    *  Define a large number of placeholders. There is no way to
 843    *  simplify this with variadic templates, because we're introducing
 844    *  unique names for each.
 845    */
 846   namespace placeholders
 847   {
 848     namespace
 849     {
 850       _Placeholder<1> _1;
 851       _Placeholder<2> _2;
 852       _Placeholder<3> _3;
 853       _Placeholder<4> _4;
 854       _Placeholder<5> _5;
 855       _Placeholder<6> _6;
 856       _Placeholder<7> _7;
 857       _Placeholder<8> _8;
 858       _Placeholder<9> _9;
 859       _Placeholder<10> _10;
 860       _Placeholder<11> _11;
 861       _Placeholder<12> _12;
 862       _Placeholder<13> _13;
 863       _Placeholder<14> _14;
 864       _Placeholder<15> _15;
 865       _Placeholder<16> _16;
 866       _Placeholder<17> _17;
 867       _Placeholder<18> _18;
 868       _Placeholder<19> _19;
 869       _Placeholder<20> _20;
 870       _Placeholder<21> _21;
 871       _Placeholder<22> _22;
 872       _Placeholder<23> _23;
 873       _Placeholder<24> _24;
 874       _Placeholder<25> _25;
 875       _Placeholder<26> _26;
 876       _Placeholder<27> _27;
 877       _Placeholder<28> _28;
 878       _Placeholder<29> _29;
 879     }
 880   }
 881
 882   /**
 883    *  Partial specialization of is_placeholder that provides the placeholder
 884    *  number for the placeholder objects defined by libstdc++.
 885    *  @ingroup binders
 886    */
 887   template<int _Num>
 888     struct is_placeholder<_Placeholder<_Num> >
 889     : public integral_constant<int, _Num>
 890     { };
 891
 892   /**
 893    * Used by _Safe_tuple_element to indicate that there is no tuple
 894    * element at this position.
 895    */
 896   struct _No_tuple_element;
 897
 898   /**
 899    * Implementation helper for _Safe_tuple_element. This primary
 900    * template handles the case where it is safe to use @c
 901    * tuple_element.
 902    */
 903   template<int __i, typename _Tuple, bool _IsSafe>
 904     struct _Safe_tuple_element_impl
 905     : tuple_element<__i, _Tuple> { };
 906
 907   /**
 908    * Implementation helper for _Safe_tuple_element. This partial
 909    * specialization handles the case where it is not safe to use @c
 910    * tuple_element. We just return @c _No_tuple_element.
 911    */
 912   template<int __i, typename _Tuple>
 913     struct _Safe_tuple_element_impl<__i, _Tuple, false>
 914     {
 915       typedef _No_tuple_element type;
 916     };
 917
 918   /**
 919    * Like tuple_element, but returns @c _No_tuple_element when
 920    * tuple_element would return an error.
 921    */
 922  template<int __i, typename _Tuple>
 923    struct _Safe_tuple_element
 924    : _Safe_tuple_element_impl<__i, _Tuple,
 925                               (__i >= 0 && __i < tuple_size<_Tuple>::value)>
 926    { };
 927
 928   /**
 929    *  Maps an argument to bind() into an actual argument to the bound
 930    *  function object [TR1 3.6.3/5]. Only the first parameter should
 931    *  be specified: the rest are used to determine among the various
 932    *  implementations. Note that, although this class is a function
 933    *  object, it isn't entirely normal because it takes only two
 934    *  parameters regardless of the number of parameters passed to the
 935    *  bind expression. The first parameter is the bound argument and
 936    *  the second parameter is a tuple containing references to the
 937    *  rest of the arguments.
 938    */
 939   template<typename _Arg,
 940            bool _IsBindExp = is_bind_expression<_Arg>::value,
 941            bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
 942     class _Mu;
 943
 944   /**
 945    *  If the argument is reference_wrapper<_Tp>, returns the
 946    *  underlying reference. [TR1 3.6.3/5 bullet 1]
 947    */
 948   template<typename _Tp>
 949     class _Mu<reference_wrapper<_Tp>, false, false>
 950     {
 951     public:
 952       typedef _Tp& result_type;
 953
 954       /* Note: This won't actually work for const volatile
 955        * reference_wrappers, because reference_wrapper::get() is const
 956        * but not volatile-qualified. This might be a defect in the TR.
 957        */
 958       template<typename _CVRef, typename _Tuple>
 959         result_type
 960         operator()(_CVRef& __arg, _Tuple&) const volatile
 961         { return __arg.get(); }
 962     };
 963
 964   /**
 965    *  If the argument is a bind expression, we invoke the underlying
 966    *  function object with the same cv-qualifiers as we are given and
 967    *  pass along all of our arguments (unwrapped). [TR1 3.6.3/5 bullet 2]
 968    */
 969   template<typename _Arg>
 970     class _Mu<_Arg, true, false>
 971     {
 972     public:
 973       template<typename _CVArg, typename... _Args>
 974         auto
 975         operator()(_CVArg& __arg,
 976                    tuple<_Args...>& __tuple) const volatile
 977         -> decltype(__arg(declval<_Args>()...))
 978         {
 979           // Construct an index tuple and forward to __call
 980           typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
 981             _Indexes;
 982           return this->__call(__arg, __tuple, _Indexes());
 983         }
 984
 985     private:
 986       // Invokes the underlying function object __arg by unpacking all
 987       // of the arguments in the tuple.
 988       template<typename _CVArg, typename... _Args, int... _Indexes>
 989         auto
 990         __call(_CVArg& __arg, tuple<_Args...>& __tuple,
 991                const _Index_tuple<_Indexes...>&) const volatile
 992         -> decltype(__arg(declval<_Args>()...))
 993         {
 994           return __arg(std::forward<_Args>(get<_Indexes>(__tuple))...);
 995         }
 996     };
 997
 998   /**
 999    *  If the argument is a placeholder for the Nth argument, returns
1000    *  a reference to the Nth argument to the bind function object.
1001    *  [TR1 3.6.3/5 bullet 3]
1002    */
1003   template<typename _Arg>
1004     class _Mu<_Arg, false, true>
1005     {
1006     public:
1007       template<typename _Signature> class result;
1008
1009       template<typename _CVMu, typename _CVArg, typename _Tuple>
1010         class result<_CVMu(_CVArg, _Tuple)>
1011         {
1012           // Add a reference, if it hasn't already been done for us.
1013           // This allows us to be a little bit sloppy in constructing
1014           // the tuple that we pass to result_of<...>.
1015           typedef typename _Safe_tuple_element<(is_placeholder<_Arg>::value
1016                                                 - 1), _Tuple>::type
1017             __base_type;
1018
1019         public:
1020           typedef typename add_rvalue_reference<__base_type>::type type;
1021         };
1022
1023       template<typename _Tuple>
1024         typename result<_Mu(_Arg, _Tuple)>::type
1025         operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
1026         {
1027           return std::forward<typename result<_Mu(_Arg, _Tuple)>::type>(
1028               ::std::get<(is_placeholder<_Arg>::value - 1)>(__tuple));
1029         }
1030     };
1031
1032   /**
1033    *  If the argument is just a value, returns a reference to that
1034    *  value. The cv-qualifiers on the reference are the same as the
1035    *  cv-qualifiers on the _Mu object. [TR1 3.6.3/5 bullet 4]
1036    */
1037   template<typename _Arg>
1038     class _Mu<_Arg, false, false>
1039     {
1040     public:
1041       template<typename _Signature> struct result;
1042
1043       template<typename _CVMu, typename _CVArg, typename _Tuple>
1044         struct result<_CVMu(_CVArg, _Tuple)>
1045         {
1046           typedef typename add_lvalue_reference<_CVArg>::type type;
1047         };
1048
1049       // Pick up the cv-qualifiers of the argument
1050       template<typename _CVArg, typename _Tuple>
1051         _CVArg&&
1052         operator()(_CVArg&& __arg, _Tuple&) const volatile
1053         { return std::forward<_CVArg>(__arg); }
1054     };
1055
1056   /**
1057    *  Maps member pointers into instances of _Mem_fn but leaves all
1058    *  other function objects untouched. Used by tr1::bind(). The
1059    *  primary template handles the non--member-pointer case.
1060    */
1061   template<typename _Tp>
1062     struct _Maybe_wrap_member_pointer
1063     {
1064       typedef _Tp type;
1065
1066       static const _Tp&
1067       __do_wrap(const _Tp& __x)
1068       { return __x; }
1069
1070       static _Tp&&
1071       __do_wrap(_Tp&& __x)
1072       { return static_cast<_Tp&&>(__x); }
1073     };
1074
1075   /**
1076    *  Maps member pointers into instances of _Mem_fn but leaves all
1077    *  other function objects untouched. Used by tr1::bind(). This
1078    *  partial specialization handles the member pointer case.
1079    */
1080   template<typename _Tp, typename _Class>
1081     struct _Maybe_wrap_member_pointer<_Tp _Class::*>
1082     {
1083       typedef _Mem_fn<_Tp _Class::*> type;
1084
1085       static type
1086       __do_wrap(_Tp _Class::* __pm)
1087       { return type(__pm); }
1088     };
1089
1090   // Specialization needed to prevent "forming reference to void" errors when
1091   // bind<void>() is called, because argument deduction instantiates
1092   // _Maybe_wrap_member_pointer<void> outside the immediate context where
1093   // SFINAE applies.
1094   template<>
1095     struct _Maybe_wrap_member_pointer<void>
1096     {
1097       typedef void type;
1098     };
1099
1100   // std::get<I> for volatile-qualified tuples
1101   template<size_t _Ind, typename... _Tp>
1102     inline auto
1103     __volget(volatile tuple<_Tp...>& __tuple)
1104     -> typename tuple_element<_Ind, tuple<_Tp...>>::type volatile&
1105     { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
1106
1107   // std::get<I> for const-volatile-qualified tuples
1108   template<size_t _Ind, typename... _Tp>
1109     inline auto
1110     __volget(const volatile tuple<_Tp...>& __tuple)
1111     -> typename tuple_element<_Ind, tuple<_Tp...>>::type const volatile&
1112     { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
1113
1114   /// Type of the function object returned from bind().
1115   template<typename _Signature>
1116     struct _Bind;
1117
1118    template<typename _Functor, typename... _Bound_args>
1119     class _Bind<_Functor(_Bound_args...)>
1120     : public _Weak_result_type<_Functor>
1121     {
1122       typedef _Bind __self_type;
1123       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1124         _Bound_indexes;
1125
1126       _Functor _M_f;
1127       tuple<_Bound_args...> _M_bound_args;
1128
1129       // Call unqualified
1130       template<typename _Result, typename... _Args, int... _Indexes>
1131         _Result
1132         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
1133         {
1134           return _M_f(_Mu<_Bound_args>()
1135                       (get<_Indexes>(_M_bound_args), __args)...);
1136         }
1137
1138       // Call as const
1139       template<typename _Result, typename... _Args, int... _Indexes>
1140         _Result
1141         __call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
1142         {
1143           return _M_f(_Mu<_Bound_args>()
1144                       (get<_Indexes>(_M_bound_args), __args)...);
1145         }
1146
1147       // Call as volatile
1148       template<typename _Result, typename... _Args, int... _Indexes>
1149         _Result
1150         __call_v(tuple<_Args...>&& __args,
1151                  _Index_tuple<_Indexes...>) volatile
1152         {
1153           return _M_f(_Mu<_Bound_args>()
1154                       (__volget<_Indexes>(_M_bound_args), __args)...);
1155         }
1156
1157       // Call as const volatile
1158       template<typename _Result, typename... _Args, int... _Indexes>
1159         _Result
1160         __call_c_v(tuple<_Args...>&& __args,
1161                    _Index_tuple<_Indexes...>) const volatile
1162         {
1163           return _M_f(_Mu<_Bound_args>()
1164                       (__volget<_Indexes>(_M_bound_args), __args)...);
1165         }
1166
1167      public:
1168       template<typename... _Args>
1169         explicit _Bind(const _Functor& __f, _Args&&... __args)
1170         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1171         { }
1172
1173       template<typename... _Args>
1174         explicit _Bind(_Functor&& __f, _Args&&... __args)
1175         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1176         { }
1177
1178       _Bind(const _Bind&) = default;
1179
1180       _Bind(_Bind&& __b)
1181       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1182       { }
1183
1184       // Call unqualified
1185       template<typename... _Args, typename _Result
1186         = decltype( std::declval<_Functor>()(
1187               _Mu<_Bound_args>()( std::declval<_Bound_args&>(),
1188                                   std::declval<tuple<_Args...>&>() )... ) )>
1189         _Result
1190         operator()(_Args&&... __args)
1191         {
1192           return this->__call<_Result>(
1193               std::forward_as_tuple(std::forward<_Args>(__args)...),
1194               _Bound_indexes());
1195         }
1196
1197       // Call as const
1198       template<typename... _Args, typename _Result
1199         = decltype( std::declval<const _Functor>()(
1200               _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
1201                                   std::declval<tuple<_Args...>&>() )... ) )>
1202         _Result
1203         operator()(_Args&&... __args) const
1204         {
1205           return this->__call_c<_Result>(
1206               std::forward_as_tuple(std::forward<_Args>(__args)...),
1207               _Bound_indexes());
1208         }
1209
1210       // Call as volatile
1211       template<typename... _Args, typename _Result
1212         = decltype( std::declval<volatile _Functor>()(
1213               _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
1214                                   std::declval<tuple<_Args...>&>() )... ) )>
1215         _Result
1216         operator()(_Args&&... __args) volatile
1217         {
1218           return this->__call_v<_Result>(
1219               std::forward_as_tuple(std::forward<_Args>(__args)...),
1220               _Bound_indexes());
1221         }
1222
1223       // Call as const volatile
1224       template<typename... _Args, typename _Result
1225         = decltype( std::declval<const volatile _Functor>()(
1226               _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
1227                                   std::declval<tuple<_Args...>&>() )... ) )>
1228         _Result
1229         operator()(_Args&&... __args) const volatile
1230         {
1231           return this->__call_c_v<_Result>(
1232               std::forward_as_tuple(std::forward<_Args>(__args)...),
1233               _Bound_indexes());
1234         }
1235     };
1236
1237   /// Type of the function object returned from bind<R>().
1238   template<typename _Result, typename _Signature>
1239     struct _Bind_result;
1240
1241   template<typename _Result, typename _Functor, typename... _Bound_args>
1242     class _Bind_result<_Result, _Functor(_Bound_args...)>
1243     {
1244       typedef _Bind_result __self_type;
1245       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1246         _Bound_indexes;
1247
1248       _Functor _M_f;
1249       tuple<_Bound_args...> _M_bound_args;
1250
1251       // sfinae types
1252       template<typename _Res>
1253         struct __enable_if_void : enable_if<is_void<_Res>::value, int> { };
1254       template<typename _Res>
1255         struct __disable_if_void : enable_if<!is_void<_Res>::value, int> { };
1256
1257       // Call unqualified
1258       template<typename _Res, typename... _Args, int... _Indexes>
1259         _Result
1260         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1261             typename __disable_if_void<_Res>::type = 0)
1262         {
1263           return _M_f(_Mu<_Bound_args>()
1264                       (get<_Indexes>(_M_bound_args), __args)...);
1265         }
1266
1267       // Call unqualified, return void
1268       template<typename _Res, typename... _Args, int... _Indexes>
1269         void
1270         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1271             typename __enable_if_void<_Res>::type = 0)
1272         {
1273           _M_f(_Mu<_Bound_args>()
1274                (get<_Indexes>(_M_bound_args), __args)...);
1275         }
1276
1277       // Call as const
1278       template<typename _Res, typename... _Args, int... _Indexes>
1279         _Result
1280         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1281             typename __disable_if_void<_Res>::type = 0) const
1282         {
1283           return _M_f(_Mu<_Bound_args>()
1284                       (get<_Indexes>(_M_bound_args), __args)...);
1285         }
1286
1287       // Call as const, return void
1288       template<typename _Res, typename... _Args, int... _Indexes>
1289         void
1290         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1291             typename __enable_if_void<_Res>::type = 0) const
1292         {
1293           _M_f(_Mu<_Bound_args>()
1294                (get<_Indexes>(_M_bound_args),  __args)...);
1295         }
1296
1297       // Call as volatile
1298       template<typename _Res, typename... _Args, int... _Indexes>
1299         _Result
1300         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1301             typename __disable_if_void<_Res>::type = 0) volatile
1302         {
1303           return _M_f(_Mu<_Bound_args>()
1304                       (__volget<_Indexes>(_M_bound_args), __args)...);
1305         }
1306
1307       // Call as volatile, return void
1308       template<typename _Res, typename... _Args, int... _Indexes>
1309         void
1310         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1311             typename __enable_if_void<_Res>::type = 0) volatile
1312         {
1313           _M_f(_Mu<_Bound_args>()
1314                (__volget<_Indexes>(_M_bound_args), __args)...);
1315         }
1316
1317       // Call as const volatile
1318       template<typename _Res, typename... _Args, int... _Indexes>
1319         _Result
1320         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1321             typename __disable_if_void<_Res>::type = 0) const volatile
1322         {
1323           return _M_f(_Mu<_Bound_args>()
1324                       (__volget<_Indexes>(_M_bound_args), __args)...);
1325         }
1326
1327       // Call as const volatile, return void
1328       template<typename _Res, typename... _Args, int... _Indexes>
1329         void
1330         __call(tuple<_Args...>&& __args,
1331                _Index_tuple<_Indexes...>,
1332             typename __enable_if_void<_Res>::type = 0) const volatile
1333         {
1334           _M_f(_Mu<_Bound_args>()
1335                (__volget<_Indexes>(_M_bound_args), __args)...);
1336         }
1337
1338     public:
1339       typedef _Result result_type;
1340
1341       template<typename... _Args>
1342         explicit _Bind_result(const _Functor& __f, _Args&&... __args)
1343         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1344         { }
1345
1346       template<typename... _Args>
1347         explicit _Bind_result(_Functor&& __f, _Args&&... __args)
1348         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1349         { }
1350
1351       _Bind_result(const _Bind_result&) = default;
1352
1353       _Bind_result(_Bind_result&& __b)
1354       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1355       { }
1356
1357       // Call unqualified
1358       template<typename... _Args>
1359         result_type
1360         operator()(_Args&&... __args)
1361         {
1362           return this->__call<_Result>(
1363               std::forward_as_tuple(std::forward<_Args>(__args)...),
1364               _Bound_indexes());
1365         }
1366
1367       // Call as const
1368       template<typename... _Args>
1369         result_type
1370         operator()(_Args&&... __args) const
1371         {
1372           return this->__call<_Result>(
1373               std::forward_as_tuple(std::forward<_Args>(__args)...),
1374               _Bound_indexes());
1375         }
1376
1377       // Call as volatile
1378       template<typename... _Args>
1379         result_type
1380         operator()(_Args&&... __args) volatile
1381         {
1382           return this->__call<_Result>(
1383               std::forward_as_tuple(std::forward<_Args>(__args)...),
1384               _Bound_indexes());
1385         }
1386
1387       // Call as const volatile
1388       template<typename... _Args>
1389         result_type
1390         operator()(_Args&&... __args) const volatile
1391         {
1392           return this->__call<_Result>(
1393               std::forward_as_tuple(std::forward<_Args>(__args)...),
1394               _Bound_indexes());
1395         }
1396     };
1397
1398   /**
1399    *  @brief Class template _Bind is always a bind expression.
1400    *  @ingroup binders
1401    */
1402   template<typename _Signature>
1403     struct is_bind_expression<_Bind<_Signature> >
1404     : public true_type { };
1405
1406   /**
1407    *  @brief Class template _Bind is always a bind expression.
1408    *  @ingroup binders
1409    */
1410   template<typename _Result, typename _Signature>
1411     struct is_bind_expression<_Bind_result<_Result, _Signature> >
1412     : public true_type { };
1413
1414   template<typename _Functor, typename... _ArgTypes>
1415     struct _Bind_helper
1416     {
1417       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1418         __maybe_type;
1419       typedef typename __maybe_type::type __functor_type;
1420       typedef _Bind<__functor_type(typename decay<_ArgTypes>::type...)> type;
1421     };
1422
1423   /**
1424    *  @brief Function template for std::bind.
1425    *  @ingroup binders
1426    */
1427   template<typename _Functor, typename... _ArgTypes>
1428     inline
1429     typename _Bind_helper<_Functor, _ArgTypes...>::type
1430     bind(_Functor&& __f, _ArgTypes&&... __args)
1431     {
1432       typedef _Bind_helper<_Functor, _ArgTypes...> __helper_type;
1433       typedef typename __helper_type::__maybe_type __maybe_type;
1434       typedef typename __helper_type::type __result_type;
1435       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1436                            std::forward<_ArgTypes>(__args)...);
1437     }
1438
1439   template<typename _Result, typename _Functor, typename... _ArgTypes>
1440     struct _Bindres_helper
1441     {
1442       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1443         __maybe_type;
1444       typedef typename __maybe_type::type __functor_type;
1445       typedef _Bind_result<_Result,
1446                            __functor_type(typename decay<_ArgTypes>::type...)>
1447         type;
1448     };
1449
1450   /**
1451    *  @brief Function template for std::bind<R>.
1452    *  @ingroup binders
1453    */
1454   template<typename _Result, typename _Functor, typename... _ArgTypes>
1455     inline
1456     typename _Bindres_helper<_Result, _Functor, _ArgTypes...>::type
1457     bind(_Functor&& __f, _ArgTypes&&... __args)
1458     {
1459       typedef _Bindres_helper<_Result, _Functor, _ArgTypes...> __helper_type;
1460       typedef typename __helper_type::__maybe_type __maybe_type;
1461       typedef typename __helper_type::type __result_type;
1462       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1463                            std::forward<_ArgTypes>(__args)...);
1464     }
1465
1466   /**
1467    *  @brief Exception class thrown when class template function's
1468    *  operator() is called with an empty target.
1469    *  @ingroup exceptions
1470    */
1471   class bad_function_call : public std::exception { };
1472
1473   /**
1474    *  Trait identifying "location-invariant" types, meaning that the
1475    *  address of the object (or any of its members) will not escape.
1476    *  Also implies a trivial copy constructor and assignment operator.
1477    */
1478   template<typename _Tp>
1479     struct __is_location_invariant
1480     : integral_constant<bool, (is_pointer<_Tp>::value
1481                                || is_member_pointer<_Tp>::value)>
1482     { };
1483
1484   class _Undefined_class;
1485
1486   union _Nocopy_types
1487   {
1488     void*       _M_object;
1489     const void* _M_const_object;
1490     void (*_M_function_pointer)();
1491     void (_Undefined_class::*_M_member_pointer)();
1492   };
1493
1494   union _Any_data
1495   {
1496     void*       _M_access()       { return &_M_pod_data[0]; }
1497     const void* _M_access() const { return &_M_pod_data[0]; }
1498
1499     template<typename _Tp>
1500       _Tp&
1501       _M_access()
1502       { return *static_cast<_Tp*>(_M_access()); }
1503
1504     template<typename _Tp>
1505       const _Tp&
1506       _M_access() const
1507       { return *static_cast<const _Tp*>(_M_access()); }
1508
1509     _Nocopy_types _M_unused;
1510     char _M_pod_data[sizeof(_Nocopy_types)];
1511   };
1512
1513   enum _Manager_operation
1514   {
1515     __get_type_info,
1516     __get_functor_ptr,
1517     __clone_functor,
1518     __destroy_functor
1519   };
1520
1521   // Simple type wrapper that helps avoid annoying const problems
1522   // when casting between void pointers and pointers-to-pointers.
1523   template<typename _Tp>
1524     struct _Simple_type_wrapper
1525     {
1526       _Simple_type_wrapper(_Tp __value) : __value(__value) { }
1527
1528       _Tp __value;
1529     };
1530
1531   template<typename _Tp>
1532     struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
1533     : __is_location_invariant<_Tp>
1534     { };
1535
1536   // Converts a reference to a function object into a callable
1537   // function object.
1538   template<typename _Functor>
1539     inline _Functor&
1540     __callable_functor(_Functor& __f)
1541     { return __f; }
1542
1543   template<typename _Member, typename _Class>
1544     inline _Mem_fn<_Member _Class::*>
1545     __callable_functor(_Member _Class::* &__p)
1546     { return mem_fn(__p); }
1547
1548   template<typename _Member, typename _Class>
1549     inline _Mem_fn<_Member _Class::*>
1550     __callable_functor(_Member _Class::* const &__p)
1551     { return mem_fn(__p); }
1552
1553   template<typename _Signature>
1554     class function;
1555
1556   /// Base class of all polymorphic function object wrappers.
1557   class _Function_base
1558   {
1559   public:
1560     static const std::size_t _M_max_size = sizeof(_Nocopy_types);
1561     static const std::size_t _M_max_align = __alignof__(_Nocopy_types);
1562
1563     template<typename _Functor>
1564       class _Base_manager
1565       {
1566       protected:
1567         static const bool __stored_locally =
1568         (__is_location_invariant<_Functor>::value
1569          && sizeof(_Functor) <= _M_max_size
1570          && __alignof__(_Functor) <= _M_max_align
1571          && (_M_max_align % __alignof__(_Functor) == 0));
1572
1573         typedef integral_constant<bool, __stored_locally> _Local_storage;
1574
1575         // Retrieve a pointer to the function object
1576         static _Functor*
1577         _M_get_pointer(const _Any_data& __source)
1578         {
1579           const _Functor* __ptr =
1580             __stored_locally? &__source._M_access<_Functor>()
1581             /* have stored a pointer */ : __source._M_access<_Functor*>();
1582           return const_cast<_Functor*>(__ptr);
1583         }
1584
1585         // Clone a location-invariant function object that fits within
1586         // an _Any_data structure.
1587         static void
1588         _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
1589         {
1590           new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
1591         }
1592
1593         // Clone a function object that is not location-invariant or
1594         // that cannot fit into an _Any_data structure.
1595         static void
1596         _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
1597         {
1598           __dest._M_access<_Functor*>() =
1599             new _Functor(*__source._M_access<_Functor*>());
1600         }
1601
1602         // Destroying a location-invariant object may still require
1603         // destruction.
1604         static void
1605         _M_destroy(_Any_data& __victim, true_type)
1606         {
1607           __victim._M_access<_Functor>().~_Functor();
1608         }
1609
1610         // Destroying an object located on the heap.
1611         static void
1612         _M_destroy(_Any_data& __victim, false_type)
1613         {
1614           delete __victim._M_access<_Functor*>();
1615         }
1616
1617       public:
1618         static bool
1619         _M_manager(_Any_data& __dest, const _Any_data& __source,
1620                    _Manager_operation __op)
1621         {
1622           switch (__op)
1623             {
1624 #ifdef __GXX_RTTI
1625             case __get_type_info:
1626               __dest._M_access<const type_info*>() = &typeid(_Functor);
1627               break;
1628 #endif
1629             case __get_functor_ptr:
1630               __dest._M_access<_Functor*>() = _M_get_pointer(__source);
1631               break;
1632
1633             case __clone_functor:
1634               _M_clone(__dest, __source, _Local_storage());
1635               break;
1636
1637             case __destroy_functor:
1638               _M_destroy(__dest, _Local_storage());
1639               break;
1640             }
1641           return false;
1642         }
1643
1644         static void
1645         _M_init_functor(_Any_data& __functor, _Functor&& __f)
1646         { _M_init_functor(__functor, std::move(__f), _Local_storage()); }
1647
1648         template<typename _Signature>
1649           static bool
1650           _M_not_empty_function(const function<_Signature>& __f)
1651           { return static_cast<bool>(__f); }
1652
1653         template<typename _Tp>
1654           static bool
1655           _M_not_empty_function(const _Tp*& __fp)
1656           { return __fp; }
1657
1658         template<typename _Class, typename _Tp>
1659           static bool
1660           _M_not_empty_function(_Tp _Class::* const& __mp)
1661           { return __mp; }
1662
1663         template<typename _Tp>
1664           static bool
1665           _M_not_empty_function(const _Tp&)
1666           { return true; }
1667
1668       private:
1669         static void
1670         _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
1671         { new (__functor._M_access()) _Functor(std::move(__f)); }
1672
1673         static void
1674         _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
1675         { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
1676       };
1677
1678     template<typename _Functor>
1679       class _Ref_manager : public _Base_manager<_Functor*>
1680       {
1681         typedef _Function_base::_Base_manager<_Functor*> _Base;
1682
1683     public:
1684         static bool
1685         _M_manager(_Any_data& __dest, const _Any_data& __source,
1686                    _Manager_operation __op)
1687         {
1688           switch (__op)
1689             {
1690 #ifdef __GXX_RTTI
1691             case __get_type_info:
1692               __dest._M_access<const type_info*>() = &typeid(_Functor);
1693               break;
1694 #endif
1695             case __get_functor_ptr:
1696               __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
1697               return is_const<_Functor>::value;
1698               break;
1699
1700             default:
1701               _Base::_M_manager(__dest, __source, __op);
1702             }
1703           return false;
1704         }
1705
1706         static void
1707         _M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
1708         {
1709           // TBD: Use address_of function instead.
1710           _Base::_M_init_functor(__functor, &__f.get());
1711         }
1712       };
1713
1714     _Function_base() : _M_manager(0) { }
1715
1716     ~_Function_base()
1717     {
1718       if (_M_manager)
1719         _M_manager(_M_functor, _M_functor, __destroy_functor);
1720     }
1721
1722
1723     bool _M_empty() const { return !_M_manager; }
1724
1725     typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
1726                                   _Manager_operation);
1727
1728     _Any_data     _M_functor;
1729     _Manager_type _M_manager;
1730   };
1731
1732   template<typename _Signature, typename _Functor>
1733     class _Function_handler;
1734
1735   template<typename _Res, typename _Functor, typename... _ArgTypes>
1736     class _Function_handler<_Res(_ArgTypes...), _Functor>
1737     : public _Function_base::_Base_manager<_Functor>
1738     {
1739       typedef _Function_base::_Base_manager<_Functor> _Base;
1740
1741     public:
1742       static _Res
1743       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1744       {
1745         return (*_Base::_M_get_pointer(__functor))(
1746             std::forward<_ArgTypes>(__args)...);
1747       }
1748     };
1749
1750   template<typename _Functor, typename... _ArgTypes>
1751     class _Function_handler<void(_ArgTypes...), _Functor>
1752     : public _Function_base::_Base_manager<_Functor>
1753     {
1754       typedef _Function_base::_Base_manager<_Functor> _Base;
1755
1756      public:
1757       static void
1758       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1759       {
1760         (*_Base::_M_get_pointer(__functor))(
1761             std::forward<_ArgTypes>(__args)...);
1762       }
1763     };
1764
1765   template<typename _Res, typename _Functor, typename... _ArgTypes>
1766     class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
1767     : public _Function_base::_Ref_manager<_Functor>
1768     {
1769       typedef _Function_base::_Ref_manager<_Functor> _Base;
1770
1771      public:
1772       static _Res
1773       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1774       {
1775         return __callable_functor(**_Base::_M_get_pointer(__functor))(
1776               std::forward<_ArgTypes>(__args)...);
1777       }
1778     };
1779
1780   template<typename _Functor, typename... _ArgTypes>
1781     class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
1782     : public _Function_base::_Ref_manager<_Functor>
1783     {
1784       typedef _Function_base::_Ref_manager<_Functor> _Base;
1785
1786      public:
1787       static void
1788       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1789       {
1790         __callable_functor(**_Base::_M_get_pointer(__functor))(
1791             std::forward<_ArgTypes>(__args)...);
1792       }
1793     };
1794
1795   template<typename _Class, typename _Member, typename _Res,
1796            typename... _ArgTypes>
1797     class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
1798     : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
1799     {
1800       typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
1801         _Base;
1802
1803      public:
1804       static _Res
1805       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1806       {
1807         return mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1808             std::forward<_ArgTypes>(__args)...);
1809       }
1810     };
1811
1812   template<typename _Class, typename _Member, typename... _ArgTypes>
1813     class _Function_handler<void(_ArgTypes...), _Member _Class::*>
1814     : public _Function_base::_Base_manager<
1815                  _Simple_type_wrapper< _Member _Class::* > >
1816     {
1817       typedef _Member _Class::* _Functor;
1818       typedef _Simple_type_wrapper<_Functor> _Wrapper;
1819       typedef _Function_base::_Base_manager<_Wrapper> _Base;
1820
1821      public:
1822       static bool
1823       _M_manager(_Any_data& __dest, const _Any_data& __source,
1824                  _Manager_operation __op)
1825       {
1826         switch (__op)
1827           {
1828 #ifdef __GXX_RTTI
1829           case __get_type_info:
1830             __dest._M_access<const type_info*>() = &typeid(_Functor);
1831             break;
1832 #endif
1833           case __get_functor_ptr:
1834             __dest._M_access<_Functor*>() =
1835               &_Base::_M_get_pointer(__source)->__value;
1836             break;
1837
1838           default:
1839             _Base::_M_manager(__dest, __source, __op);
1840           }
1841         return false;
1842       }
1843
1844       static void
1845       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1846       {
1847         mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1848             std::forward<_ArgTypes>(__args)...);
1849       }
1850     };
1851
1852   /**
1853    *  @brief Primary class template for std::function.
1854    *  @ingroup functors
1855    *
1856    *  Polymorphic function wrapper.
1857    */
1858   template<typename _Res, typename... _ArgTypes>
1859     class function<_Res(_ArgTypes...)>
1860     : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
1861       private _Function_base
1862     {
1863       typedef _Res _Signature_type(_ArgTypes...);
1864
1865       struct _Useless { };
1866
1867     public:
1868       typedef _Res result_type;
1869
1870       // [3.7.2.1] construct/copy/destroy
1871
1872       /**
1873        *  @brief Default construct creates an empty function call wrapper.
1874        *  @post @c !(bool)*this
1875        */
1876       function() : _Function_base() { }
1877
1878       /**
1879        *  @brief Creates an empty function call wrapper.
1880        *  @post @c !(bool)*this
1881        */
1882       function(nullptr_t) : _Function_base() { }
1883
1884       /**
1885        *  @brief %Function copy constructor.
1886        *  @param x A %function object with identical call signature.
1887        *  @post @c (bool)*this == (bool)x
1888        *
1889        *  The newly-created %function contains a copy of the target of @a
1890        *  x (if it has one).
1891        */
1892       function(const function& __x);
1893
1894       /**
1895        *  @brief %Function move constructor.
1896        *  @param x A %function object rvalue with identical call signature.
1897        *
1898        *  The newly-created %function contains the target of @a x
1899        *  (if it has one).
1900        */
1901       function(function&& __x) : _Function_base()
1902       {
1903         __x.swap(*this);
1904       }
1905
1906       // TODO: needs allocator_arg_t
1907
1908       /**
1909        *  @brief Builds a %function that targets a copy of the incoming
1910        *  function object.
1911        *  @param f A %function object that is callable with parameters of
1912        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1913        *  to @c Res.
1914        *
1915        *  The newly-created %function object will target a copy of @a
1916        *  f. If @a f is @c reference_wrapper<F>, then this function
1917        *  object will contain a reference to the function object @c
1918        *  f.get(). If @a f is a NULL function pointer or NULL
1919        *  pointer-to-member, the newly-created object will be empty.
1920        *
1921        *  If @a f is a non-NULL function pointer or an object of type @c
1922        *  reference_wrapper<F>, this function will not throw.
1923        */
1924       template<typename _Functor>
1925         function(_Functor __f,
1926                  typename enable_if<
1927                            !is_integral<_Functor>::value, _Useless>::type
1928                    = _Useless());
1929
1930       /**
1931        *  @brief %Function assignment operator.
1932        *  @param x A %function with identical call signature.
1933        *  @post @c (bool)*this == (bool)x
1934        *  @returns @c *this
1935        *
1936        *  The target of @a x is copied to @c *this. If @a x has no
1937        *  target, then @c *this will be empty.
1938        *
1939        *  If @a x targets a function pointer or a reference to a function
1940        *  object, then this operation will not throw an %exception.
1941        */
1942       function&
1943       operator=(const function& __x)
1944       {
1945         function(__x).swap(*this);
1946         return *this;
1947       }
1948
1949       /**
1950        *  @brief %Function move-assignment operator.
1951        *  @param x A %function rvalue with identical call signature.
1952        *  @returns @c *this
1953        *
1954        *  The target of @a x is moved to @c *this. If @a x has no
1955        *  target, then @c *this will be empty.
1956        *
1957        *  If @a x targets a function pointer or a reference to a function
1958        *  object, then this operation will not throw an %exception.
1959        */
1960       function&
1961       operator=(function&& __x)
1962       {
1963         function(std::move(__x)).swap(*this);
1964         return *this;
1965       }
1966
1967       /**
1968        *  @brief %Function assignment to zero.
1969        *  @post @c !(bool)*this
1970        *  @returns @c *this
1971        *
1972        *  The target of @c *this is deallocated, leaving it empty.
1973        */
1974       function&
1975       operator=(nullptr_t)
1976       {
1977         if (_M_manager)
1978           {
1979             _M_manager(_M_functor, _M_functor, __destroy_functor);
1980             _M_manager = 0;
1981             _M_invoker = 0;
1982           }
1983         return *this;
1984       }
1985
1986       /**
1987        *  @brief %Function assignment to a new target.
1988        *  @param f A %function object that is callable with parameters of
1989        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1990        *  to @c Res.
1991        *  @return @c *this
1992        *
1993        *  This  %function object wrapper will target a copy of @a
1994        *  f. If @a f is @c reference_wrapper<F>, then this function
1995        *  object will contain a reference to the function object @c
1996        *  f.get(). If @a f is a NULL function pointer or NULL
1997        *  pointer-to-member, @c this object will be empty.
1998        *
1999        *  If @a f is a non-NULL function pointer or an object of type @c
2000        *  reference_wrapper<F>, this function will not throw.
2001        */
2002       template<typename _Functor>
2003         typename enable_if<!is_integral<_Functor>::value, function&>::type
2004         operator=(_Functor&& __f)
2005         {
2006           function(std::forward<_Functor>(__f)).swap(*this);
2007           return *this;
2008         }
2009
2010       /// @overload
2011       template<typename _Functor>
2012         typename enable_if<!is_integral<_Functor>::value, function&>::type
2013         operator=(reference_wrapper<_Functor> __f)
2014         {
2015           function(__f).swap(*this);
2016           return *this;
2017         }
2018
2019       // [3.7.2.2] function modifiers
2020
2021       /**
2022        *  @brief Swap the targets of two %function objects.
2023        *  @param f A %function with identical call signature.
2024        *
2025        *  Swap the targets of @c this function object and @a f. This
2026        *  function will not throw an %exception.
2027        */
2028       void swap(function& __x)
2029       {
2030         std::swap(_M_functor, __x._M_functor);
2031         std::swap(_M_manager, __x._M_manager);
2032         std::swap(_M_invoker, __x._M_invoker);
2033       }
2034
2035       // TODO: needs allocator_arg_t
2036       /*
2037       template<typename _Functor, typename _Alloc>
2038         void
2039         assign(_Functor&& __f, const _Alloc& __a)
2040         {
2041           function(allocator_arg, __a,
2042                    std::forward<_Functor>(__f)).swap(*this);
2043         }
2044       */
2045
2046       // [3.7.2.3] function capacity
2047
2048       /**
2049        *  @brief Determine if the %function wrapper has a target.
2050        *
2051        *  @return @c true when this %function object contains a target,
2052        *  or @c false when it is empty.
2053        *
2054        *  This function will not throw an %exception.
2055        */
2056       explicit operator bool() const
2057       { return !_M_empty(); }
2058
2059       // [3.7.2.4] function invocation
2060
2061       /**
2062        *  @brief Invokes the function targeted by @c *this.
2063        *  @returns the result of the target.
2064        *  @throws bad_function_call when @c !(bool)*this
2065        *
2066        *  The function call operator invokes the target function object
2067        *  stored by @c this.
2068        */
2069       _Res operator()(_ArgTypes... __args) const;
2070
2071 #ifdef __GXX_RTTI
2072       // [3.7.2.5] function target access
2073       /**
2074        *  @brief Determine the type of the target of this function object
2075        *  wrapper.
2076        *
2077        *  @returns the type identifier of the target function object, or
2078        *  @c typeid(void) if @c !(bool)*this.
2079        *
2080        *  This function will not throw an %exception.
2081        */
2082       const type_info& target_type() const;
2083
2084       /**
2085        *  @brief Access the stored target function object.
2086        *
2087        *  @return Returns a pointer to the stored target function object,
2088        *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
2089        *  pointer.
2090        *
2091        * This function will not throw an %exception.
2092        */
2093       template<typename _Functor>       _Functor* target();
2094
2095       /// @overload
2096       template<typename _Functor> const _Functor* target() const;
2097 #endif
2098
2099       // deleted overloads
2100       template<typename _Res2, typename... _ArgTypes2>
2101         void operator==(const function<_Res2(_ArgTypes2...)>&) const = delete;
2102       template<typename _Res2, typename... _ArgTypes2>
2103         void operator!=(const function<_Res2(_ArgTypes2...)>&) const = delete;
2104
2105     private:
2106       typedef _Res (*_Invoker_type)(const _Any_data&, _ArgTypes...);
2107       _Invoker_type _M_invoker;
2108   };
2109
2110   // Out-of-line member definitions.
2111   template<typename _Res, typename... _ArgTypes>
2112     function<_Res(_ArgTypes...)>::
2113     function(const function& __x)
2114     : _Function_base()
2115     {
2116       if (static_cast<bool>(__x))
2117         {
2118           _M_invoker = __x._M_invoker;
2119           _M_manager = __x._M_manager;
2120           __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
2121         }
2122     }
2123
2124   template<typename _Res, typename... _ArgTypes>
2125     template<typename _Functor>
2126       function<_Res(_ArgTypes...)>::
2127       function(_Functor __f,
2128                typename enable_if<
2129                         !is_integral<_Functor>::value, _Useless>::type)
2130       : _Function_base()
2131       {
2132         typedef _Function_handler<_Signature_type, _Functor> _My_handler;
2133
2134         if (_My_handler::_M_not_empty_function(__f))
2135           {
2136             _M_invoker = &_My_handler::_M_invoke;
2137             _M_manager = &_My_handler::_M_manager;
2138             _My_handler::_M_init_functor(_M_functor, std::move(__f));
2139           }
2140       }
2141
2142   template<typename _Res, typename... _ArgTypes>
2143     _Res
2144     function<_Res(_ArgTypes...)>::
2145     operator()(_ArgTypes... __args) const
2146     {
2147       if (_M_empty())
2148         __throw_bad_function_call();
2149       return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
2150     }
2151
2152 #ifdef __GXX_RTTI
2153   template<typename _Res, typename... _ArgTypes>
2154     const type_info&
2155     function<_Res(_ArgTypes...)>::
2156     target_type() const
2157     {
2158       if (_M_manager)
2159         {
2160           _Any_data __typeinfo_result;
2161           _M_manager(__typeinfo_result, _M_functor, __get_type_info);
2162           return *__typeinfo_result._M_access<const type_info*>();
2163         }
2164       else
2165         return typeid(void);
2166     }
2167
2168   template<typename _Res, typename... _ArgTypes>
2169     template<typename _Functor>
2170       _Functor*
2171       function<_Res(_ArgTypes...)>::
2172       target()
2173       {
2174         if (typeid(_Functor) == target_type() && _M_manager)
2175           {
2176             _Any_data __ptr;
2177             if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
2178                 && !is_const<_Functor>::value)
2179               return 0;
2180             else
2181               return __ptr._M_access<_Functor*>();
2182           }
2183         else
2184           return 0;
2185       }
2186
2187   template<typename _Res, typename... _ArgTypes>
2188     template<typename _Functor>
2189       const _Functor*
2190       function<_Res(_ArgTypes...)>::
2191       target() const
2192       {
2193         if (typeid(_Functor) == target_type() && _M_manager)
2194           {
2195             _Any_data __ptr;
2196             _M_manager(__ptr, _M_functor, __get_functor_ptr);
2197             return __ptr._M_access<const _Functor*>();
2198           }
2199         else
2200           return 0;
2201       }
2202 #endif
2203
2204   // [20.7.15.2.6] null pointer comparisons
2205
2206   /**
2207    *  @brief Compares a polymorphic function object wrapper against 0
2208    *  (the NULL pointer).
2209    *  @returns @c true if the wrapper has no target, @c false otherwise
2210    *
2211    *  This function will not throw an %exception.
2212    */
2213   template<typename _Res, typename... _Args>
2214     inline bool
2215     operator==(const function<_Res(_Args...)>& __f, nullptr_t)
2216     { return !static_cast<bool>(__f); }
2217
2218   /// @overload
2219   template<typename _Res, typename... _Args>
2220     inline bool
2221     operator==(nullptr_t, const function<_Res(_Args...)>& __f)
2222     { return !static_cast<bool>(__f); }
2223
2224   /**
2225    *  @brief Compares a polymorphic function object wrapper against 0
2226    *  (the NULL pointer).
2227    *  @returns @c false if the wrapper has no target, @c true otherwise
2228    *
2229    *  This function will not throw an %exception.
2230    */
2231   template<typename _Res, typename... _Args>
2232     inline bool
2233     operator!=(const function<_Res(_Args...)>& __f, nullptr_t)
2234     { return static_cast<bool>(__f); }
2235
2236   /// @overload
2237   template<typename _Res, typename... _Args>
2238     inline bool
2239     operator!=(nullptr_t, const function<_Res(_Args...)>& __f)
2240     { return static_cast<bool>(__f); }
2241
2242   // [20.7.15.2.7] specialized algorithms
2243
2244   /**
2245    *  @brief Swap the targets of two polymorphic function object wrappers.
2246    *
2247    *  This function will not throw an %exception.
2248    */
2249   template<typename _Res, typename... _Args>
2250     inline void
2251     swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
2252     { __x.swap(__y); }
2253 }
2254
2255 #endif // __GXX_EXPERIMENTAL_CXX0X__
2256
2257 #endif // _GLIBCXX_FUNCTIONAL