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

   1 // Multiset implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   4 // 2011 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  *
  28  * Copyright (c) 1994
  29  * Hewlett-Packard Company
  30  *
  31  * Permission to use, copy, modify, distribute and sell this software
  32  * and its documentation for any purpose is hereby granted without fee,
  33  * provided that the above copyright notice appear in all copies and
  34  * that both that copyright notice and this permission notice appear
  35  * in supporting documentation.  Hewlett-Packard Company makes no
  36  * representations about the suitability of this software for any
  37  * purpose.  It is provided "as is" without express or implied warranty.
  38  *
  39  *
  40  * Copyright (c) 1996
  41  * Silicon Graphics Computer Systems, Inc.
  42  *
  43  * Permission to use, copy, modify, distribute and sell this software
  44  * and its documentation for any purpose is hereby granted without fee,
  45  * provided that the above copyright notice appear in all copies and
  46  * that both that copyright notice and this permission notice appear
  47  * in supporting documentation.  Silicon Graphics makes no
  48  * representations about the suitability of this software for any
  49  * purpose.  It is provided "as is" without express or implied warranty.
  50  */
  51
  52 /** @file bits/stl_multiset.h
  53  *  This is an internal header file, included by other library headers.
  54  *  Do not attempt to use it directly. @headername{set}
  55  */
  56
  57 #ifndef _STL_MULTISET_H
  58 #define _STL_MULTISET_H 1
  59
  60 #include <bits/concept_check.h>
  61 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  62 #include <initializer_list>
  63 #endif
  64
  65 namespace std _GLIBCXX_VISIBILITY(default)
  66 {
  67 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
  68
  69   /**
  70    *  @brief A standard container made up of elements, which can be retrieved
  71    *  in logarithmic time.
  72    *
  73    *  @ingroup associative_containers
  74    *
  75    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
  76    *  <a href="tables.html#66">reversible container</a>, and an
  77    *  <a href="tables.html#69">associative container</a> (using equivalent
  78    *  keys).  For a @c multiset<Key> the key_type and value_type are Key.
  79    *
  80    *  Multisets support bidirectional iterators.
  81    *
  82    *  The private tree data is declared exactly the same way for set and
  83    *  multiset; the distinction is made entirely in how the tree functions are
  84    *  called (*_unique versus *_equal, same as the standard).
  85   */
  86   template <typename _Key, typename _Compare = std::less<_Key>,
  87             typename _Alloc = std::allocator<_Key> >
  88     class multiset
  89     {
  90       // concept requirements
  91       typedef typename _Alloc::value_type                   _Alloc_value_type;
  92       __glibcxx_class_requires(_Key, _SGIAssignableConcept)
  93       __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
  94                                 _BinaryFunctionConcept)
  95       __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
  96
  97     public:
  98       // typedefs:
  99       typedef _Key     key_type;
 100       typedef _Key     value_type;
 101       typedef _Compare key_compare;
 102       typedef _Compare value_compare;
 103       typedef _Alloc   allocator_type;
 104
 105     private:
 106       /// This turns a red-black tree into a [multi]set.
 107       typedef typename _Alloc::template rebind<_Key>::other _Key_alloc_type;
 108
 109       typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
 110                        key_compare, _Key_alloc_type> _Rep_type;
 111       /// The actual tree structure.
 112       _Rep_type _M_t;
 113
 114     public:
 115       typedef typename _Key_alloc_type::pointer             pointer;
 116       typedef typename _Key_alloc_type::const_pointer       const_pointer;
 117       typedef typename _Key_alloc_type::reference           reference;
 118       typedef typename _Key_alloc_type::const_reference     const_reference;
 119       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 120       // DR 103. set::iterator is required to be modifiable,
 121       // but this allows modification of keys.
 122       typedef typename _Rep_type::const_iterator            iterator;
 123       typedef typename _Rep_type::const_iterator            const_iterator;
 124       typedef typename _Rep_type::const_reverse_iterator    reverse_iterator;
 125       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
 126       typedef typename _Rep_type::size_type                 size_type;
 127       typedef typename _Rep_type::difference_type           difference_type;
 128
 129       // allocation/deallocation
 130       /**
 131        *  @brief  Default constructor creates no elements.
 132        */
 133       multiset()
 134       : _M_t() { }
 135
 136       /**
 137        *  @brief  Creates a %multiset with no elements.
 138        *  @param  __comp  Comparator to use.
 139        *  @param  __a  An allocator object.
 140        */
 141       explicit
 142       multiset(const _Compare& __comp,
 143                const allocator_type& __a = allocator_type())
 144       : _M_t(__comp, _Key_alloc_type(__a)) { }
 145
 146       /**
 147        *  @brief  Builds a %multiset from a range.
 148        *  @param  __first  An input iterator.
 149        *  @param  __last  An input iterator.
 150        *
 151        *  Create a %multiset consisting of copies of the elements from
 152        *  [first,last).  This is linear in N if the range is already sorted,
 153        *  and NlogN otherwise (where N is distance(__first,__last)).
 154        */
 155       template<typename _InputIterator>
 156         multiset(_InputIterator __first, _InputIterator __last)
 157         : _M_t()
 158         { _M_t._M_insert_equal(__first, __last); }
 159
 160       /**
 161        *  @brief  Builds a %multiset from a range.
 162        *  @param  __first  An input iterator.
 163        *  @param  __last  An input iterator.
 164        *  @param  __comp  A comparison functor.
 165        *  @param  __a  An allocator object.
 166        *
 167        *  Create a %multiset consisting of copies of the elements from
 168        *  [__first,__last).  This is linear in N if the range is already sorted,
 169        *  and NlogN otherwise (where N is distance(__first,__last)).
 170        */
 171       template<typename _InputIterator>
 172         multiset(_InputIterator __first, _InputIterator __last,
 173                  const _Compare& __comp,
 174                  const allocator_type& __a = allocator_type())
 175         : _M_t(__comp, _Key_alloc_type(__a))
 176         { _M_t._M_insert_equal(__first, __last); }
 177
 178       /**
 179        *  @brief  %Multiset copy constructor.
 180        *  @param  __x  A %multiset of identical element and allocator types.
 181        *
 182        *  The newly-created %multiset uses a copy of the allocation object used
 183        *  by @a __x.
 184        */
 185       multiset(const multiset& __x)
 186       : _M_t(__x._M_t) { }
 187
 188 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 189      /**
 190        *  @brief  %Multiset move constructor.
 191        *  @param  __x  A %multiset of identical element and allocator types.
 192        *
 193        *  The newly-created %multiset contains the exact contents of @a __x.
 194        *  The contents of @a __x are a valid, but unspecified %multiset.
 195        */
 196       multiset(multiset&& __x)
 197       noexcept(is_nothrow_copy_constructible<_Compare>::value)
 198       : _M_t(std::move(__x._M_t)) { }
 199
 200       /**
 201        *  @brief  Builds a %multiset from an initializer_list.
 202        *  @param  __l  An initializer_list.
 203        *  @param  __comp  A comparison functor.
 204        *  @param  __a  An allocator object.
 205        *
 206        *  Create a %multiset consisting of copies of the elements from
 207        *  the list.  This is linear in N if the list is already sorted,
 208        *  and NlogN otherwise (where N is @a __l.size()).
 209        */
 210       multiset(initializer_list<value_type> __l,
 211                const _Compare& __comp = _Compare(),
 212                const allocator_type& __a = allocator_type())
 213       : _M_t(__comp, _Key_alloc_type(__a))
 214       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
 215 #endif
 216
 217       /**
 218        *  @brief  %Multiset assignment operator.
 219        *  @param  __x  A %multiset of identical element and allocator types.
 220        *
 221        *  All the elements of @a __x are copied, but unlike the copy
 222        *  constructor, the allocator object is not copied.
 223        */
 224       multiset&
 225       operator=(const multiset& __x)
 226       {
 227         _M_t = __x._M_t;
 228         return *this;
 229       }
 230
 231 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 232       /**
 233        *  @brief  %Multiset move assignment operator.
 234        *  @param  __x  A %multiset of identical element and allocator types.
 235        *
 236        *  The contents of @a __x are moved into this %multiset
 237        *  (without copying).  @a __x is a valid, but unspecified
 238        *  %multiset.
 239        */
 240       multiset&
 241       operator=(multiset&& __x)
 242       {
 243         // NB: DR 1204.
 244         // NB: DR 675.
 245         this->clear();
 246         this->swap(__x);
 247         return *this;
 248       }
 249
 250       /**
 251        *  @brief  %Multiset list assignment operator.
 252        *  @param  __l  An initializer_list.
 253        *
 254        *  This function fills a %multiset with copies of the elements in the
 255        *  initializer list @a __l.
 256        *
 257        *  Note that the assignment completely changes the %multiset and
 258        *  that the resulting %multiset's size is the same as the number
 259        *  of elements assigned.  Old data may be lost.
 260        */
 261       multiset&
 262       operator=(initializer_list<value_type> __l)
 263       {
 264         this->clear();
 265         this->insert(__l.begin(), __l.end());
 266         return *this;
 267       }
 268 #endif
 269
 270       // accessors:
 271
 272       ///  Returns the comparison object.
 273       key_compare
 274       key_comp() const
 275       { return _M_t.key_comp(); }
 276       ///  Returns the comparison object.
 277       value_compare
 278       value_comp() const
 279       { return _M_t.key_comp(); }
 280       ///  Returns the memory allocation object.
 281       allocator_type
 282       get_allocator() const _GLIBCXX_NOEXCEPT
 283       { return allocator_type(_M_t.get_allocator()); }
 284
 285       /**
 286        *  Returns a read-only (constant) iterator that points to the first
 287        *  element in the %multiset.  Iteration is done in ascending order
 288        *  according to the keys.
 289        */
 290       iterator
 291       begin() const _GLIBCXX_NOEXCEPT
 292       { return _M_t.begin(); }
 293
 294       /**
 295        *  Returns a read-only (constant) iterator that points one past the last
 296        *  element in the %multiset.  Iteration is done in ascending order
 297        *  according to the keys.
 298        */
 299       iterator
 300       end() const _GLIBCXX_NOEXCEPT
 301       { return _M_t.end(); }
 302
 303       /**
 304        *  Returns a read-only (constant) reverse iterator that points to the
 305        *  last element in the %multiset.  Iteration is done in descending order
 306        *  according to the keys.
 307        */
 308       reverse_iterator
 309       rbegin() const _GLIBCXX_NOEXCEPT
 310       { return _M_t.rbegin(); }
 311
 312       /**
 313        *  Returns a read-only (constant) reverse iterator that points to the
 314        *  last element in the %multiset.  Iteration is done in descending order
 315        *  according to the keys.
 316        */
 317       reverse_iterator
 318       rend() const _GLIBCXX_NOEXCEPT
 319       { return _M_t.rend(); }
 320
 321 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 322       /**
 323        *  Returns a read-only (constant) iterator that points to the first
 324        *  element in the %multiset.  Iteration is done in ascending order
 325        *  according to the keys.
 326        */
 327       iterator
 328       cbegin() const noexcept
 329       { return _M_t.begin(); }
 330
 331       /**
 332        *  Returns a read-only (constant) iterator that points one past the last
 333        *  element in the %multiset.  Iteration is done in ascending order
 334        *  according to the keys.
 335        */
 336       iterator
 337       cend() const noexcept
 338       { return _M_t.end(); }
 339
 340       /**
 341        *  Returns a read-only (constant) reverse iterator that points to the
 342        *  last element in the %multiset.  Iteration is done in descending order
 343        *  according to the keys.
 344        */
 345       reverse_iterator
 346       crbegin() const noexcept
 347       { return _M_t.rbegin(); }
 348
 349       /**
 350        *  Returns a read-only (constant) reverse iterator that points to the
 351        *  last element in the %multiset.  Iteration is done in descending order
 352        *  according to the keys.
 353        */
 354       reverse_iterator
 355       crend() const noexcept
 356       { return _M_t.rend(); }
 357 #endif
 358
 359       ///  Returns true if the %set is empty.
 360       bool
 361       empty() const _GLIBCXX_NOEXCEPT
 362       { return _M_t.empty(); }
 363
 364       ///  Returns the size of the %set.
 365       size_type
 366       size() const _GLIBCXX_NOEXCEPT
 367       { return _M_t.size(); }
 368
 369       ///  Returns the maximum size of the %set.
 370       size_type
 371       max_size() const _GLIBCXX_NOEXCEPT
 372       { return _M_t.max_size(); }
 373
 374       /**
 375        *  @brief  Swaps data with another %multiset.
 376        *  @param  __x  A %multiset of the same element and allocator types.
 377        *
 378        *  This exchanges the elements between two multisets in constant time.
 379        *  (It is only swapping a pointer, an integer, and an instance of the @c
 380        *  Compare type (which itself is often stateless and empty), so it should
 381        *  be quite fast.)
 382        *  Note that the global std::swap() function is specialized such that
 383        *  std::swap(s1,s2) will feed to this function.
 384        */
 385       void
 386       swap(multiset& __x)
 387       { _M_t.swap(__x._M_t); }
 388
 389       // insert/erase
 390       /**
 391        *  @brief Inserts an element into the %multiset.
 392        *  @param  __x  Element to be inserted.
 393        *  @return An iterator that points to the inserted element.
 394        *
 395        *  This function inserts an element into the %multiset.  Contrary
 396        *  to a std::set the %multiset does not rely on unique keys and thus
 397        *  multiple copies of the same element can be inserted.
 398        *
 399        *  Insertion requires logarithmic time.
 400        */
 401       iterator
 402       insert(const value_type& __x)
 403       { return _M_t._M_insert_equal(__x); }
 404
 405 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 406       iterator
 407       insert(value_type&& __x)
 408       { return _M_t._M_insert_equal(std::move(__x)); }
 409 #endif
 410
 411       /**
 412        *  @brief Inserts an element into the %multiset.
 413        *  @param  __position  An iterator that serves as a hint as to where the
 414        *                    element should be inserted.
 415        *  @param  __x  Element to be inserted.
 416        *  @return An iterator that points to the inserted element.
 417        *
 418        *  This function inserts an element into the %multiset.  Contrary
 419        *  to a std::set the %multiset does not rely on unique keys and thus
 420        *  multiple copies of the same element can be inserted.
 421        *
 422        *  Note that the first parameter is only a hint and can potentially
 423        *  improve the performance of the insertion process.  A bad hint would
 424        *  cause no gains in efficiency.
 425        *
 426        *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
 427        *  for more on @a hinting.
 428        *
 429        *  Insertion requires logarithmic time (if the hint is not taken).
 430        */
 431       iterator
 432       insert(const_iterator __position, const value_type& __x)
 433       { return _M_t._M_insert_equal_(__position, __x); }
 434
 435 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 436       iterator
 437       insert(const_iterator __position, value_type&& __x)
 438       { return _M_t._M_insert_equal_(__position, std::move(__x)); }
 439 #endif
 440
 441       /**
 442        *  @brief A template function that tries to insert a range of elements.
 443        *  @param  __first  Iterator pointing to the start of the range to be
 444        *                   inserted.
 445        *  @param  __last  Iterator pointing to the end of the range.
 446        *
 447        *  Complexity similar to that of the range constructor.
 448        */
 449       template<typename _InputIterator>
 450         void
 451         insert(_InputIterator __first, _InputIterator __last)
 452         { _M_t._M_insert_equal(__first, __last); }
 453
 454 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 455       /**
 456        *  @brief Attempts to insert a list of elements into the %multiset.
 457        *  @param  __l  A std::initializer_list<value_type> of elements
 458        *               to be inserted.
 459        *
 460        *  Complexity similar to that of the range constructor.
 461        */
 462       void
 463       insert(initializer_list<value_type> __l)
 464       { this->insert(__l.begin(), __l.end()); }
 465 #endif
 466
 467 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 468       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 469       // DR 130. Associative erase should return an iterator.
 470       /**
 471        *  @brief Erases an element from a %multiset.
 472        *  @param  __position  An iterator pointing to the element to be erased.
 473        *  @return An iterator pointing to the element immediately following
 474        *          @a position prior to the element being erased. If no such
 475        *          element exists, end() is returned.
 476        *
 477        *  This function erases an element, pointed to by the given iterator,
 478        *  from a %multiset.  Note that this function only erases the element,
 479        *  and that if the element is itself a pointer, the pointed-to memory is
 480        *  not touched in any way.  Managing the pointer is the user's
 481        *  responsibility.
 482        */
 483       iterator
 484       erase(const_iterator __position)
 485       { return _M_t.erase(__position); }
 486 #else
 487       /**
 488        *  @brief Erases an element from a %multiset.
 489        *  @param  __position  An iterator pointing to the element to be erased.
 490        *
 491        *  This function erases an element, pointed to by the given iterator,
 492        *  from a %multiset.  Note that this function only erases the element,
 493        *  and that if the element is itself a pointer, the pointed-to memory is
 494        *  not touched in any way.  Managing the pointer is the user's
 495        *  responsibility.
 496        */
 497       void
 498       erase(iterator __position)
 499       { _M_t.erase(__position); }
 500 #endif
 501
 502       /**
 503        *  @brief Erases elements according to the provided key.
 504        *  @param  __x  Key of element to be erased.
 505        *  @return  The number of elements erased.
 506        *
 507        *  This function erases all elements located by the given key from a
 508        *  %multiset.
 509        *  Note that this function only erases the element, and that if
 510        *  the element is itself a pointer, the pointed-to memory is not touched
 511        *  in any way.  Managing the pointer is the user's responsibility.
 512        */
 513       size_type
 514       erase(const key_type& __x)
 515       { return _M_t.erase(__x); }
 516
 517 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 518       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 519       // DR 130. Associative erase should return an iterator.
 520       /**
 521        *  @brief Erases a [first,last) range of elements from a %multiset.
 522        *  @param  __first  Iterator pointing to the start of the range to be
 523        *                   erased.
 524        *  @param __last Iterator pointing to the end of the range to
 525        *                be erased.
 526        *  @return The iterator @a last.
 527        *
 528        *  This function erases a sequence of elements from a %multiset.
 529        *  Note that this function only erases the elements, and that if
 530        *  the elements themselves are pointers, the pointed-to memory is not
 531        *  touched in any way.  Managing the pointer is the user's
 532        *  responsibility.
 533        */
 534       iterator
 535       erase(const_iterator __first, const_iterator __last)
 536       { return _M_t.erase(__first, __last); }
 537 #else
 538       /**
 539        *  @brief Erases a [first,last) range of elements from a %multiset.
 540        *  @param  first  Iterator pointing to the start of the range to be
 541        *                 erased.
 542        *  @param  last  Iterator pointing to the end of the range to be erased.
 543        *
 544        *  This function erases a sequence of elements from a %multiset.
 545        *  Note that this function only erases the elements, and that if
 546        *  the elements themselves are pointers, the pointed-to memory is not
 547        *  touched in any way.  Managing the pointer is the user's
 548        *  responsibility.
 549        */
 550       void
 551       erase(iterator __first, iterator __last)
 552       { _M_t.erase(__first, __last); }
 553 #endif
 554
 555       /**
 556        *  Erases all elements in a %multiset.  Note that this function only
 557        *  erases the elements, and that if the elements themselves are pointers,
 558        *  the pointed-to memory is not touched in any way.  Managing the pointer
 559        *  is the user's responsibility.
 560        */
 561       void
 562       clear() _GLIBCXX_NOEXCEPT
 563       { _M_t.clear(); }
 564
 565       // multiset operations:
 566
 567       /**
 568        *  @brief Finds the number of elements with given key.
 569        *  @param  __x  Key of elements to be located.
 570        *  @return Number of elements with specified key.
 571        */
 572       size_type
 573       count(const key_type& __x) const
 574       { return _M_t.count(__x); }
 575
 576       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 577       // 214.  set::find() missing const overload
 578       //@{
 579       /**
 580        *  @brief Tries to locate an element in a %set.
 581        *  @param  __x  Element to be located.
 582        *  @return  Iterator pointing to sought-after element, or end() if not
 583        *           found.
 584        *
 585        *  This function takes a key and tries to locate the element with which
 586        *  the key matches.  If successful the function returns an iterator
 587        *  pointing to the sought after element.  If unsuccessful it returns the
 588        *  past-the-end ( @c end() ) iterator.
 589        */
 590       iterator
 591       find(const key_type& __x)
 592       { return _M_t.find(__x); }
 593
 594       const_iterator
 595       find(const key_type& __x) const
 596       { return _M_t.find(__x); }
 597       //@}
 598
 599       //@{
 600       /**
 601        *  @brief Finds the beginning of a subsequence matching given key.
 602        *  @param  __x  Key to be located.
 603        *  @return  Iterator pointing to first element equal to or greater
 604        *           than key, or end().
 605        *
 606        *  This function returns the first element of a subsequence of elements
 607        *  that matches the given key.  If unsuccessful it returns an iterator
 608        *  pointing to the first element that has a greater value than given key
 609        *  or end() if no such element exists.
 610        */
 611       iterator
 612       lower_bound(const key_type& __x)
 613       { return _M_t.lower_bound(__x); }
 614
 615       const_iterator
 616       lower_bound(const key_type& __x) const
 617       { return _M_t.lower_bound(__x); }
 618       //@}
 619
 620       //@{
 621       /**
 622        *  @brief Finds the end of a subsequence matching given key.
 623        *  @param  __x  Key to be located.
 624        *  @return Iterator pointing to the first element
 625        *          greater than key, or end().
 626        */
 627       iterator
 628       upper_bound(const key_type& __x)
 629       { return _M_t.upper_bound(__x); }
 630
 631       const_iterator
 632       upper_bound(const key_type& __x) const
 633       { return _M_t.upper_bound(__x); }
 634       //@}
 635
 636       //@{
 637       /**
 638        *  @brief Finds a subsequence matching given key.
 639        *  @param  __x  Key to be located.
 640        *  @return  Pair of iterators that possibly points to the subsequence
 641        *           matching given key.
 642        *
 643        *  This function is equivalent to
 644        *  @code
 645        *    std::make_pair(c.lower_bound(val),
 646        *                   c.upper_bound(val))
 647        *  @endcode
 648        *  (but is faster than making the calls separately).
 649        *
 650        *  This function probably only makes sense for multisets.
 651        */
 652       std::pair<iterator, iterator>
 653       equal_range(const key_type& __x)
 654       { return _M_t.equal_range(__x); }
 655
 656       std::pair<const_iterator, const_iterator>
 657       equal_range(const key_type& __x) const
 658       { return _M_t.equal_range(__x); }
 659       //@}
 660
 661       template<typename _K1, typename _C1, typename _A1>
 662         friend bool
 663         operator==(const multiset<_K1, _C1, _A1>&,
 664                    const multiset<_K1, _C1, _A1>&);
 665
 666       template<typename _K1, typename _C1, typename _A1>
 667         friend bool
 668         operator< (const multiset<_K1, _C1, _A1>&,
 669                    const multiset<_K1, _C1, _A1>&);
 670     };
 671
 672   /**
 673    *  @brief  Multiset equality comparison.
 674    *  @param  __x  A %multiset.
 675    *  @param  __y  A %multiset of the same type as @a __x.
 676    *  @return  True iff the size and elements of the multisets are equal.
 677    *
 678    *  This is an equivalence relation.  It is linear in the size of the
 679    *  multisets.
 680    *  Multisets are considered equivalent if their sizes are equal, and if
 681    *  corresponding elements compare equal.
 682   */
 683   template<typename _Key, typename _Compare, typename _Alloc>
 684     inline bool
 685     operator==(const multiset<_Key, _Compare, _Alloc>& __x,
 686                const multiset<_Key, _Compare, _Alloc>& __y)
 687     { return __x._M_t == __y._M_t; }
 688
 689   /**
 690    *  @brief  Multiset ordering relation.
 691    *  @param  __x  A %multiset.
 692    *  @param  __y  A %multiset of the same type as @a __x.
 693    *  @return  True iff @a __x is lexicographically less than @a __y.
 694    *
 695    *  This is a total ordering relation.  It is linear in the size of the
 696    *  maps.  The elements must be comparable with @c <.
 697    *
 698    *  See std::lexicographical_compare() for how the determination is made.
 699   */
 700   template<typename _Key, typename _Compare, typename _Alloc>
 701     inline bool
 702     operator<(const multiset<_Key, _Compare, _Alloc>& __x,
 703               const multiset<_Key, _Compare, _Alloc>& __y)
 704     { return __x._M_t < __y._M_t; }
 705
 706   ///  Returns !(x == y).
 707   template<typename _Key, typename _Compare, typename _Alloc>
 708     inline bool
 709     operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
 710                const multiset<_Key, _Compare, _Alloc>& __y)
 711     { return !(__x == __y); }
 712
 713   ///  Returns y < x.
 714   template<typename _Key, typename _Compare, typename _Alloc>
 715     inline bool
 716     operator>(const multiset<_Key,_Compare,_Alloc>& __x,
 717               const multiset<_Key,_Compare,_Alloc>& __y)
 718     { return __y < __x; }
 719
 720   ///  Returns !(y < x)
 721   template<typename _Key, typename _Compare, typename _Alloc>
 722     inline bool
 723     operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
 724                const multiset<_Key, _Compare, _Alloc>& __y)
 725     { return !(__y < __x); }
 726
 727   ///  Returns !(x < y)
 728   template<typename _Key, typename _Compare, typename _Alloc>
 729     inline bool
 730     operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
 731                const multiset<_Key, _Compare, _Alloc>& __y)
 732     { return !(__x < __y); }
 733
 734   /// See std::multiset::swap().
 735   template<typename _Key, typename _Compare, typename _Alloc>
 736     inline void
 737     swap(multiset<_Key, _Compare, _Alloc>& __x,
 738          multiset<_Key, _Compare, _Alloc>& __y)
 739     { __x.swap(__y); }
 740
 741 _GLIBCXX_END_NAMESPACE_CONTAINER
 742 } // namespace std
 743
 744 #endif /* _STL_MULTISET_H */