libstdc++-v3/include/bits/stl_multiset.h

   1 // Multiset implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001-2014 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  *
  27  * Copyright (c) 1994
  28  * Hewlett-Packard Company
  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.  Hewlett-Packard Company 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  * Copyright (c) 1996
  40  * Silicon Graphics Computer Systems, Inc.
  41  *
  42  * Permission to use, copy, modify, distribute and sell this software
  43  * and its documentation for any purpose is hereby granted without fee,
  44  * provided that the above copyright notice appear in all copies and
  45  * that both that copyright notice and this permission notice appear
  46  * in supporting documentation.  Silicon Graphics makes no
  47  * representations about the suitability of this software for any
  48  * purpose.  It is provided "as is" without express or implied warranty.
  49  */
  50
  51 /** @file bits/stl_multiset.h
  52  *  This is an internal header file, included by other library headers.
  53  *  Do not attempt to use it directly. @headername{set}
  54  */
  55
  56 #ifndef _STL_MULTISET_H
  57 #define _STL_MULTISET_H 1
  58
  59 #include <bits/concept_check.h>
  60 #if __cplusplus >= 201103L
  61 #include <initializer_list>
  62 #endif
  63
  64 namespace std _GLIBCXX_VISIBILITY(default)
  65 {
  66 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
  67
  68   /**
  69    *  @brief A standard container made up of elements, which can be retrieved
  70    *  in logarithmic time.
  71    *
  72    *  @ingroup associative_containers
  73    *
  74    *
  75    *  @tparam _Key  Type of key objects.
  76    *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
  77    *  @tparam _Alloc  Allocator type, defaults to allocator<_Key>.
  78    *
  79    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
  80    *  <a href="tables.html#66">reversible container</a>, and an
  81    *  <a href="tables.html#69">associative container</a> (using equivalent
  82    *  keys).  For a @c multiset<Key> the key_type and value_type are Key.
  83    *
  84    *  Multisets support bidirectional iterators.
  85    *
  86    *  The private tree data is declared exactly the same way for set and
  87    *  multiset; the distinction is made entirely in how the tree functions are
  88    *  called (*_unique versus *_equal, same as the standard).
  89   */
  90   template <typename _Key, typename _Compare = std::less<_Key>,
  91             typename _Alloc = std::allocator<_Key> >
  92     class multiset
  93     {
  94       // concept requirements
  95       typedef typename _Alloc::value_type                   _Alloc_value_type;
  96       __glibcxx_class_requires(_Key, _SGIAssignableConcept)
  97       __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
  98                                 _BinaryFunctionConcept)
  99       __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
 100
 101     public:
 102       // typedefs:
 103       typedef _Key     key_type;
 104       typedef _Key     value_type;
 105       typedef _Compare key_compare;
 106       typedef _Compare value_compare;
 107       typedef _Alloc   allocator_type;
 108
 109     private:
 110       /// This turns a red-black tree into a [multi]set.
 111       typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
 112         rebind<_Key>::other _Key_alloc_type;
 113
 114       typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
 115                        key_compare, _Key_alloc_type> _Rep_type;
 116       /// The actual tree structure.
 117       _Rep_type _M_t;
 118
 119       typedef __gnu_cxx::__alloc_traits<_Key_alloc_type> _Alloc_traits;
 120
 121     public:
 122       typedef typename _Alloc_traits::pointer               pointer;
 123       typedef typename _Alloc_traits::const_pointer         const_pointer;
 124       typedef typename _Alloc_traits::reference             reference;
 125       typedef typename _Alloc_traits::const_reference       const_reference;
 126       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 127       // DR 103. set::iterator is required to be modifiable,
 128       // but this allows modification of keys.
 129       typedef typename _Rep_type::const_iterator            iterator;
 130       typedef typename _Rep_type::const_iterator            const_iterator;
 131       typedef typename _Rep_type::const_reverse_iterator    reverse_iterator;
 132       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
 133       typedef typename _Rep_type::size_type                 size_type;
 134       typedef typename _Rep_type::difference_type           difference_type;
 135
 136       // allocation/deallocation
 137       /**
 138        *  @brief  Default constructor creates no elements.
 139        */
 140       multiset()
 141       : _M_t() { }
 142
 143       /**
 144        *  @brief  Creates a %multiset with no elements.
 145        *  @param  __comp  Comparator to use.
 146        *  @param  __a  An allocator object.
 147        */
 148       explicit
 149       multiset(const _Compare& __comp,
 150                const allocator_type& __a = allocator_type())
 151       : _M_t(__comp, _Key_alloc_type(__a)) { }
 152
 153       /**
 154        *  @brief  Builds a %multiset from a range.
 155        *  @param  __first  An input iterator.
 156        *  @param  __last  An input iterator.
 157        *
 158        *  Create a %multiset consisting of copies of the elements from
 159        *  [first,last).  This is linear in N if the range is already sorted,
 160        *  and NlogN otherwise (where N is distance(__first,__last)).
 161        */
 162       template<typename _InputIterator>
 163         multiset(_InputIterator __first, _InputIterator __last)
 164         : _M_t()
 165         { _M_t._M_insert_equal(__first, __last); }
 166
 167       /**
 168        *  @brief  Builds a %multiset from a range.
 169        *  @param  __first  An input iterator.
 170        *  @param  __last  An input iterator.
 171        *  @param  __comp  A comparison functor.
 172        *  @param  __a  An allocator object.
 173        *
 174        *  Create a %multiset consisting of copies of the elements from
 175        *  [__first,__last).  This is linear in N if the range is already sorted,
 176        *  and NlogN otherwise (where N is distance(__first,__last)).
 177        */
 178       template<typename _InputIterator>
 179         multiset(_InputIterator __first, _InputIterator __last,
 180                  const _Compare& __comp,
 181                  const allocator_type& __a = allocator_type())
 182         : _M_t(__comp, _Key_alloc_type(__a))
 183         { _M_t._M_insert_equal(__first, __last); }
 184
 185       /**
 186        *  @brief  %Multiset copy constructor.
 187        *  @param  __x  A %multiset of identical element and allocator types.
 188        *
 189        *  The newly-created %multiset uses a copy of the allocation object used
 190        *  by @a __x.
 191        */
 192       multiset(const multiset& __x)
 193       : _M_t(__x._M_t) { }
 194
 195 #if __cplusplus >= 201103L
 196      /**
 197        *  @brief  %Multiset move constructor.
 198        *  @param  __x  A %multiset of identical element and allocator types.
 199        *
 200        *  The newly-created %multiset contains the exact contents of @a __x.
 201        *  The contents of @a __x are a valid, but unspecified %multiset.
 202        */
 203       multiset(multiset&& __x)
 204       noexcept(is_nothrow_copy_constructible<_Compare>::value)
 205       : _M_t(std::move(__x._M_t)) { }
 206
 207       /**
 208        *  @brief  Builds a %multiset from an initializer_list.
 209        *  @param  __l  An initializer_list.
 210        *  @param  __comp  A comparison functor.
 211        *  @param  __a  An allocator object.
 212        *
 213        *  Create a %multiset consisting of copies of the elements from
 214        *  the list.  This is linear in N if the list is already sorted,
 215        *  and NlogN otherwise (where N is @a __l.size()).
 216        */
 217       multiset(initializer_list<value_type> __l,
 218                const _Compare& __comp = _Compare(),
 219                const allocator_type& __a = allocator_type())
 220       : _M_t(__comp, _Key_alloc_type(__a))
 221       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
 222
 223       /// Allocator-extended default constructor.
 224       explicit
 225       multiset(const allocator_type& __a)
 226       : _M_t(_Compare(), _Key_alloc_type(__a)) { }
 227
 228       /// Allocator-extended copy constructor.
 229       multiset(const multiset& __m, const allocator_type& __a)
 230       : _M_t(__m._M_t, _Key_alloc_type(__a)) { }
 231
 232       /// Allocator-extended move constructor.
 233       multiset(multiset&& __m, const allocator_type& __a)
 234       noexcept(is_nothrow_copy_constructible<_Compare>::value
 235                && _Alloc_traits::_S_always_equal())
 236       : _M_t(std::move(__m._M_t), _Key_alloc_type(__a)) { }
 237
 238       /// Allocator-extended initialier-list constructor.
 239       multiset(initializer_list<value_type> __l, const allocator_type& __a)
 240       : _M_t(_Compare(), _Key_alloc_type(__a))
 241       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
 242
 243       /// Allocator-extended range constructor.
 244       template<typename _InputIterator>
 245         multiset(_InputIterator __first, _InputIterator __last,
 246                  const allocator_type& __a)
 247         : _M_t(_Compare(), _Key_alloc_type(__a))
 248         { _M_t._M_insert_equal(__first, __last); }
 249 #endif
 250
 251       /**
 252        *  @brief  %Multiset assignment operator.
 253        *  @param  __x  A %multiset of identical element and allocator types.
 254        *
 255        *  All the elements of @a __x are copied, but unlike the copy
 256        *  constructor, the allocator object is not copied.
 257        */
 258       multiset&
 259       operator=(const multiset& __x)
 260       {
 261         _M_t = __x._M_t;
 262         return *this;
 263       }
 264
 265 #if __cplusplus >= 201103L
 266       /// Move assignment operator.
 267       multiset&
 268       operator=(multiset&&) = default;
 269
 270       /**
 271        *  @brief  %Multiset list assignment operator.
 272        *  @param  __l  An initializer_list.
 273        *
 274        *  This function fills a %multiset with copies of the elements in the
 275        *  initializer list @a __l.
 276        *
 277        *  Note that the assignment completely changes the %multiset and
 278        *  that the resulting %multiset's size is the same as the number
 279        *  of elements assigned.  Old data may be lost.
 280        */
 281       multiset&
 282       operator=(initializer_list<value_type> __l)
 283       {
 284         _M_t._M_assign_equal(__l.begin(), __l.end());
 285         return *this;
 286       }
 287 #endif
 288
 289       // accessors:
 290
 291       ///  Returns the comparison object.
 292       key_compare
 293       key_comp() const
 294       { return _M_t.key_comp(); }
 295       ///  Returns the comparison object.
 296       value_compare
 297       value_comp() const
 298       { return _M_t.key_comp(); }
 299       ///  Returns the memory allocation object.
 300       allocator_type
 301       get_allocator() const _GLIBCXX_NOEXCEPT
 302       { return allocator_type(_M_t.get_allocator()); }
 303
 304       /**
 305        *  Returns a read-only (constant) iterator that points to the first
 306        *  element in the %multiset.  Iteration is done in ascending order
 307        *  according to the keys.
 308        */
 309       iterator
 310       begin() const _GLIBCXX_NOEXCEPT
 311       { return _M_t.begin(); }
 312
 313       /**
 314        *  Returns a read-only (constant) iterator that points one past the last
 315        *  element in the %multiset.  Iteration is done in ascending order
 316        *  according to the keys.
 317        */
 318       iterator
 319       end() const _GLIBCXX_NOEXCEPT
 320       { return _M_t.end(); }
 321
 322       /**
 323        *  Returns a read-only (constant) reverse iterator that points to the
 324        *  last element in the %multiset.  Iteration is done in descending order
 325        *  according to the keys.
 326        */
 327       reverse_iterator
 328       rbegin() const _GLIBCXX_NOEXCEPT
 329       { return _M_t.rbegin(); }
 330
 331       /**
 332        *  Returns a read-only (constant) reverse iterator that points to the
 333        *  last element in the %multiset.  Iteration is done in descending order
 334        *  according to the keys.
 335        */
 336       reverse_iterator
 337       rend() const _GLIBCXX_NOEXCEPT
 338       { return _M_t.rend(); }
 339
 340 #if __cplusplus >= 201103L
 341       /**
 342        *  Returns a read-only (constant) iterator that points to the first
 343        *  element in the %multiset.  Iteration is done in ascending order
 344        *  according to the keys.
 345        */
 346       iterator
 347       cbegin() const noexcept
 348       { return _M_t.begin(); }
 349
 350       /**
 351        *  Returns a read-only (constant) iterator that points one past the last
 352        *  element in the %multiset.  Iteration is done in ascending order
 353        *  according to the keys.
 354        */
 355       iterator
 356       cend() const noexcept
 357       { return _M_t.end(); }
 358
 359       /**
 360        *  Returns a read-only (constant) reverse iterator that points to the
 361        *  last element in the %multiset.  Iteration is done in descending order
 362        *  according to the keys.
 363        */
 364       reverse_iterator
 365       crbegin() const noexcept
 366       { return _M_t.rbegin(); }
 367
 368       /**
 369        *  Returns a read-only (constant) reverse iterator that points to the
 370        *  last element in the %multiset.  Iteration is done in descending order
 371        *  according to the keys.
 372        */
 373       reverse_iterator
 374       crend() const noexcept
 375       { return _M_t.rend(); }
 376 #endif
 377
 378       ///  Returns true if the %set is empty.
 379       bool
 380       empty() const _GLIBCXX_NOEXCEPT
 381       { return _M_t.empty(); }
 382
 383       ///  Returns the size of the %set.
 384       size_type
 385       size() const _GLIBCXX_NOEXCEPT
 386       { return _M_t.size(); }
 387
 388       ///  Returns the maximum size of the %set.
 389       size_type
 390       max_size() const _GLIBCXX_NOEXCEPT
 391       { return _M_t.max_size(); }
 392
 393       /**
 394        *  @brief  Swaps data with another %multiset.
 395        *  @param  __x  A %multiset of the same element and allocator types.
 396        *
 397        *  This exchanges the elements between two multisets in constant time.
 398        *  (It is only swapping a pointer, an integer, and an instance of the @c
 399        *  Compare type (which itself is often stateless and empty), so it should
 400        *  be quite fast.)
 401        *  Note that the global std::swap() function is specialized such that
 402        *  std::swap(s1,s2) will feed to this function.
 403        */
 404       void
 405       swap(multiset& __x)
 406 #if __cplusplus >= 201103L
 407       noexcept(_Alloc_traits::_S_nothrow_swap())
 408 #endif
 409       { _M_t.swap(__x._M_t); }
 410
 411       // insert/erase
 412 #if __cplusplus >= 201103L
 413       /**
 414        *  @brief Builds and inserts an element into the %multiset.
 415        *  @param  __args  Arguments used to generate the element instance to be
 416        *                 inserted.
 417        *  @return An iterator that points to the inserted element.
 418        *
 419        *  This function inserts an element into the %multiset.  Contrary
 420        *  to a std::set the %multiset does not rely on unique keys and thus
 421        *  multiple copies of the same element can be inserted.
 422        *
 423        *  Insertion requires logarithmic time.
 424        */
 425       template<typename... _Args>
 426         iterator
 427         emplace(_Args&&... __args)
 428         { return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
 429
 430       /**
 431        *  @brief Builds and inserts an element into the %multiset.
 432        *  @param  __pos  An iterator that serves as a hint as to where the
 433        *                element should be inserted.
 434        *  @param  __args  Arguments used to generate the element instance to be
 435        *                 inserted.
 436        *  @return An iterator that points to the inserted element.
 437        *
 438        *  This function inserts an element into the %multiset.  Contrary
 439        *  to a std::set the %multiset does not rely on unique keys and thus
 440        *  multiple copies of the same element can be inserted.
 441        *
 442        *  Note that the first parameter is only a hint and can potentially
 443        *  improve the performance of the insertion process.  A bad hint would
 444        *  cause no gains in efficiency.
 445        *
 446        *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
 447        *  for more on @a hinting.
 448        *
 449        *  Insertion requires logarithmic time (if the hint is not taken).
 450        */
 451       template<typename... _Args>
 452         iterator
 453         emplace_hint(const_iterator __pos, _Args&&... __args)
 454         {
 455           return _M_t._M_emplace_hint_equal(__pos,
 456                                             std::forward<_Args>(__args)...);
 457         }
 458 #endif
 459
 460       /**
 461        *  @brief Inserts an element into the %multiset.
 462        *  @param  __x  Element to be inserted.
 463        *  @return An iterator that points to the inserted element.
 464        *
 465        *  This function inserts an element into the %multiset.  Contrary
 466        *  to a std::set the %multiset does not rely on unique keys and thus
 467        *  multiple copies of the same element can be inserted.
 468        *
 469        *  Insertion requires logarithmic time.
 470        */
 471       iterator
 472       insert(const value_type& __x)
 473       { return _M_t._M_insert_equal(__x); }
 474
 475 #if __cplusplus >= 201103L
 476       iterator
 477       insert(value_type&& __x)
 478       { return _M_t._M_insert_equal(std::move(__x)); }
 479 #endif
 480
 481       /**
 482        *  @brief Inserts an element into the %multiset.
 483        *  @param  __position  An iterator that serves as a hint as to where the
 484        *                    element should be inserted.
 485        *  @param  __x  Element to be inserted.
 486        *  @return An iterator that points to the inserted element.
 487        *
 488        *  This function inserts an element into the %multiset.  Contrary
 489        *  to a std::set the %multiset does not rely on unique keys and thus
 490        *  multiple copies of the same element can be inserted.
 491        *
 492        *  Note that the first parameter is only a hint and can potentially
 493        *  improve the performance of the insertion process.  A bad hint would
 494        *  cause no gains in efficiency.
 495        *
 496        *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
 497        *  for more on @a hinting.
 498        *
 499        *  Insertion requires logarithmic time (if the hint is not taken).
 500        */
 501       iterator
 502       insert(const_iterator __position, const value_type& __x)
 503       { return _M_t._M_insert_equal_(__position, __x); }
 504
 505 #if __cplusplus >= 201103L
 506       iterator
 507       insert(const_iterator __position, value_type&& __x)
 508       { return _M_t._M_insert_equal_(__position, std::move(__x)); }
 509 #endif
 510
 511       /**
 512        *  @brief A template function that tries to insert a range of elements.
 513        *  @param  __first  Iterator pointing to the start of the range to be
 514        *                   inserted.
 515        *  @param  __last  Iterator pointing to the end of the range.
 516        *
 517        *  Complexity similar to that of the range constructor.
 518        */
 519       template<typename _InputIterator>
 520         void
 521         insert(_InputIterator __first, _InputIterator __last)
 522         { _M_t._M_insert_equal(__first, __last); }
 523
 524 #if __cplusplus >= 201103L
 525       /**
 526        *  @brief Attempts to insert a list of elements into the %multiset.
 527        *  @param  __l  A std::initializer_list<value_type> of elements
 528        *               to be inserted.
 529        *
 530        *  Complexity similar to that of the range constructor.
 531        */
 532       void
 533       insert(initializer_list<value_type> __l)
 534       { this->insert(__l.begin(), __l.end()); }
 535 #endif
 536
 537 #if __cplusplus >= 201103L
 538       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 539       // DR 130. Associative erase should return an iterator.
 540       /**
 541        *  @brief Erases an element from a %multiset.
 542        *  @param  __position  An iterator pointing to the element to be erased.
 543        *  @return An iterator pointing to the element immediately following
 544        *          @a position prior to the element being erased. If no such
 545        *          element exists, end() is returned.
 546        *
 547        *  This function erases an element, pointed to by the given iterator,
 548        *  from a %multiset.  Note that this function only erases the element,
 549        *  and that if the element is itself a pointer, the pointed-to memory is
 550        *  not touched in any way.  Managing the pointer is the user's
 551        *  responsibility.
 552        */
 553       _GLIBCXX_ABI_TAG_CXX11
 554       iterator
 555       erase(const_iterator __position)
 556       { return _M_t.erase(__position); }
 557 #else
 558       /**
 559        *  @brief Erases an element from a %multiset.
 560        *  @param  __position  An iterator pointing to the element to be erased.
 561        *
 562        *  This function erases an element, pointed to by the given iterator,
 563        *  from a %multiset.  Note that this function only erases the element,
 564        *  and that if the element is itself a pointer, the pointed-to memory is
 565        *  not touched in any way.  Managing the pointer is the user's
 566        *  responsibility.
 567        */
 568       void
 569       erase(iterator __position)
 570       { _M_t.erase(__position); }
 571 #endif
 572
 573       /**
 574        *  @brief Erases elements according to the provided key.
 575        *  @param  __x  Key of element to be erased.
 576        *  @return  The number of elements erased.
 577        *
 578        *  This function erases all elements located by the given key from a
 579        *  %multiset.
 580        *  Note that this function only erases the element, and that if
 581        *  the element is itself a pointer, the pointed-to memory is not touched
 582        *  in any way.  Managing the pointer is the user's responsibility.
 583        */
 584       size_type
 585       erase(const key_type& __x)
 586       { return _M_t.erase(__x); }
 587
 588 #if __cplusplus >= 201103L
 589       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 590       // DR 130. Associative erase should return an iterator.
 591       /**
 592        *  @brief Erases a [first,last) range of elements from a %multiset.
 593        *  @param  __first  Iterator pointing to the start of the range to be
 594        *                   erased.
 595        *  @param __last Iterator pointing to the end of the range to
 596        *                be erased.
 597        *  @return The iterator @a last.
 598        *
 599        *  This function erases a sequence of elements from a %multiset.
 600        *  Note that this function only erases the elements, and that if
 601        *  the elements themselves are pointers, the pointed-to memory is not
 602        *  touched in any way.  Managing the pointer is the user's
 603        *  responsibility.
 604        */
 605       _GLIBCXX_ABI_TAG_CXX11
 606       iterator
 607       erase(const_iterator __first, const_iterator __last)
 608       { return _M_t.erase(__first, __last); }
 609 #else
 610       /**
 611        *  @brief Erases a [first,last) range of elements from a %multiset.
 612        *  @param  first  Iterator pointing to the start of the range to be
 613        *                 erased.
 614        *  @param  last  Iterator pointing to the end of the range to be erased.
 615        *
 616        *  This function erases a sequence of elements from a %multiset.
 617        *  Note that this function only erases the elements, and that if
 618        *  the elements themselves are pointers, the pointed-to memory is not
 619        *  touched in any way.  Managing the pointer is the user's
 620        *  responsibility.
 621        */
 622       void
 623       erase(iterator __first, iterator __last)
 624       { _M_t.erase(__first, __last); }
 625 #endif
 626
 627       /**
 628        *  Erases all elements in a %multiset.  Note that this function only
 629        *  erases the elements, and that if the elements themselves are pointers,
 630        *  the pointed-to memory is not touched in any way.  Managing the pointer
 631        *  is the user's responsibility.
 632        */
 633       void
 634       clear() _GLIBCXX_NOEXCEPT
 635       { _M_t.clear(); }
 636
 637       // multiset operations:
 638
 639       /**
 640        *  @brief Finds the number of elements with given key.
 641        *  @param  __x  Key of elements to be located.
 642        *  @return Number of elements with specified key.
 643        */
 644       size_type
 645       count(const key_type& __x) const
 646       { return _M_t.count(__x); }
 647
 648       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 649       // 214.  set::find() missing const overload
 650       //@{
 651       /**
 652        *  @brief Tries to locate an element in a %set.
 653        *  @param  __x  Element to be located.
 654        *  @return  Iterator pointing to sought-after element, or end() if not
 655        *           found.
 656        *
 657        *  This function takes a key and tries to locate the element with which
 658        *  the key matches.  If successful the function returns an iterator
 659        *  pointing to the sought after element.  If unsuccessful it returns the
 660        *  past-the-end ( @c end() ) iterator.
 661        */
 662       iterator
 663       find(const key_type& __x)
 664       { return _M_t.find(__x); }
 665
 666       const_iterator
 667       find(const key_type& __x) const
 668       { return _M_t.find(__x); }
 669       //@}
 670
 671       //@{
 672       /**
 673        *  @brief Finds the beginning of a subsequence matching given key.
 674        *  @param  __x  Key to be located.
 675        *  @return  Iterator pointing to first element equal to or greater
 676        *           than key, or end().
 677        *
 678        *  This function returns the first element of a subsequence of elements
 679        *  that matches the given key.  If unsuccessful it returns an iterator
 680        *  pointing to the first element that has a greater value than given key
 681        *  or end() if no such element exists.
 682        */
 683       iterator
 684       lower_bound(const key_type& __x)
 685       { return _M_t.lower_bound(__x); }
 686
 687       const_iterator
 688       lower_bound(const key_type& __x) const
 689       { return _M_t.lower_bound(__x); }
 690       //@}
 691
 692       //@{
 693       /**
 694        *  @brief Finds the end of a subsequence matching given key.
 695        *  @param  __x  Key to be located.
 696        *  @return Iterator pointing to the first element
 697        *          greater than key, or end().
 698        */
 699       iterator
 700       upper_bound(const key_type& __x)
 701       { return _M_t.upper_bound(__x); }
 702
 703       const_iterator
 704       upper_bound(const key_type& __x) const
 705       { return _M_t.upper_bound(__x); }
 706       //@}
 707
 708       //@{
 709       /**
 710        *  @brief Finds a subsequence matching given key.
 711        *  @param  __x  Key to be located.
 712        *  @return  Pair of iterators that possibly points to the subsequence
 713        *           matching given key.
 714        *
 715        *  This function is equivalent to
 716        *  @code
 717        *    std::make_pair(c.lower_bound(val),
 718        *                   c.upper_bound(val))
 719        *  @endcode
 720        *  (but is faster than making the calls separately).
 721        *
 722        *  This function probably only makes sense for multisets.
 723        */
 724       std::pair<iterator, iterator>
 725       equal_range(const key_type& __x)
 726       { return _M_t.equal_range(__x); }
 727
 728       std::pair<const_iterator, const_iterator>
 729       equal_range(const key_type& __x) const
 730       { return _M_t.equal_range(__x); }
 731       //@}
 732
 733       template<typename _K1, typename _C1, typename _A1>
 734         friend bool
 735         operator==(const multiset<_K1, _C1, _A1>&,
 736                    const multiset<_K1, _C1, _A1>&);
 737
 738       template<typename _K1, typename _C1, typename _A1>
 739         friend bool
 740         operator< (const multiset<_K1, _C1, _A1>&,
 741                    const multiset<_K1, _C1, _A1>&);
 742     };
 743
 744   /**
 745    *  @brief  Multiset equality comparison.
 746    *  @param  __x  A %multiset.
 747    *  @param  __y  A %multiset of the same type as @a __x.
 748    *  @return  True iff the size and elements of the multisets are equal.
 749    *
 750    *  This is an equivalence relation.  It is linear in the size of the
 751    *  multisets.
 752    *  Multisets are considered equivalent if their sizes are equal, and if
 753    *  corresponding elements compare equal.
 754   */
 755   template<typename _Key, typename _Compare, typename _Alloc>
 756     inline bool
 757     operator==(const multiset<_Key, _Compare, _Alloc>& __x,
 758                const multiset<_Key, _Compare, _Alloc>& __y)
 759     { return __x._M_t == __y._M_t; }
 760
 761   /**
 762    *  @brief  Multiset ordering relation.
 763    *  @param  __x  A %multiset.
 764    *  @param  __y  A %multiset of the same type as @a __x.
 765    *  @return  True iff @a __x is lexicographically less than @a __y.
 766    *
 767    *  This is a total ordering relation.  It is linear in the size of the
 768    *  sets.  The elements must be comparable with @c <.
 769    *
 770    *  See std::lexicographical_compare() for how the determination is made.
 771   */
 772   template<typename _Key, typename _Compare, typename _Alloc>
 773     inline bool
 774     operator<(const multiset<_Key, _Compare, _Alloc>& __x,
 775               const multiset<_Key, _Compare, _Alloc>& __y)
 776     { return __x._M_t < __y._M_t; }
 777
 778   ///  Returns !(x == y).
 779   template<typename _Key, typename _Compare, typename _Alloc>
 780     inline bool
 781     operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
 782                const multiset<_Key, _Compare, _Alloc>& __y)
 783     { return !(__x == __y); }
 784
 785   ///  Returns y < x.
 786   template<typename _Key, typename _Compare, typename _Alloc>
 787     inline bool
 788     operator>(const multiset<_Key,_Compare,_Alloc>& __x,
 789               const multiset<_Key,_Compare,_Alloc>& __y)
 790     { return __y < __x; }
 791
 792   ///  Returns !(y < x)
 793   template<typename _Key, typename _Compare, typename _Alloc>
 794     inline bool
 795     operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
 796                const multiset<_Key, _Compare, _Alloc>& __y)
 797     { return !(__y < __x); }
 798
 799   ///  Returns !(x < y)
 800   template<typename _Key, typename _Compare, typename _Alloc>
 801     inline bool
 802     operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
 803                const multiset<_Key, _Compare, _Alloc>& __y)
 804     { return !(__x < __y); }
 805
 806   /// See std::multiset::swap().
 807   template<typename _Key, typename _Compare, typename _Alloc>
 808     inline void
 809     swap(multiset<_Key, _Compare, _Alloc>& __x,
 810          multiset<_Key, _Compare, _Alloc>& __y)
 811     { __x.swap(__y); }
 812
 813 _GLIBCXX_END_NAMESPACE_CONTAINER
 814 } // namespace std
 815
 816 #endif /* _STL_MULTISET_H */