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, 2012 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    *
  76    *  @tparam _Key  Type of key objects.
  77    *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
  78    *  @tparam _Alloc  Allocator type, defaults to allocator<_Key>.
  79    *
  80    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
  81    *  <a href="tables.html#66">reversible container</a>, and an
  82    *  <a href="tables.html#69">associative container</a> (using equivalent
  83    *  keys).  For a @c multiset<Key> the key_type and value_type are Key.
  84    *
  85    *  Multisets support bidirectional iterators.
  86    *
  87    *  The private tree data is declared exactly the same way for set and
  88    *  multiset; the distinction is made entirely in how the tree functions are
  89    *  called (*_unique versus *_equal, same as the standard).
  90   */
  91   template <typename _Key, typename _Compare = std::less<_Key>,
  92             typename _Alloc = std::allocator<_Key> >
  93     class multiset
  94     {
  95       // concept requirements
  96       typedef typename _Alloc::value_type                   _Alloc_value_type;
  97       __glibcxx_class_requires(_Key, _SGIAssignableConcept)
  98       __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
  99                                 _BinaryFunctionConcept)
 100       __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
 101
 102     public:
 103       // typedefs:
 104       typedef _Key     key_type;
 105       typedef _Key     value_type;
 106       typedef _Compare key_compare;
 107       typedef _Compare value_compare;
 108       typedef _Alloc   allocator_type;
 109
 110     private:
 111       /// This turns a red-black tree into a [multi]set.
 112       typedef typename _Alloc::template 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     public:
 120       typedef typename _Key_alloc_type::pointer             pointer;
 121       typedef typename _Key_alloc_type::const_pointer       const_pointer;
 122       typedef typename _Key_alloc_type::reference           reference;
 123       typedef typename _Key_alloc_type::const_reference     const_reference;
 124       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 125       // DR 103. set::iterator is required to be modifiable,
 126       // but this allows modification of keys.
 127       typedef typename _Rep_type::const_iterator            iterator;
 128       typedef typename _Rep_type::const_iterator            const_iterator;
 129       typedef typename _Rep_type::const_reverse_iterator    reverse_iterator;
 130       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
 131       typedef typename _Rep_type::size_type                 size_type;
 132       typedef typename _Rep_type::difference_type           difference_type;
 133
 134       // allocation/deallocation
 135       /**
 136        *  @brief  Default constructor creates no elements.
 137        */
 138       multiset()
 139       : _M_t() { }
 140
 141       /**
 142        *  @brief  Creates a %multiset with no elements.
 143        *  @param  __comp  Comparator to use.
 144        *  @param  __a  An allocator object.
 145        */
 146       explicit
 147       multiset(const _Compare& __comp,
 148                const allocator_type& __a = allocator_type())
 149       : _M_t(__comp, _Key_alloc_type(__a)) { }
 150
 151       /**
 152        *  @brief  Builds a %multiset from a range.
 153        *  @param  __first  An input iterator.
 154        *  @param  __last  An input iterator.
 155        *
 156        *  Create a %multiset consisting of copies of the elements from
 157        *  [first,last).  This is linear in N if the range is already sorted,
 158        *  and NlogN otherwise (where N is distance(__first,__last)).
 159        */
 160       template<typename _InputIterator>
 161         multiset(_InputIterator __first, _InputIterator __last)
 162         : _M_t()
 163         { _M_t._M_insert_equal(__first, __last); }
 164
 165       /**
 166        *  @brief  Builds a %multiset from a range.
 167        *  @param  __first  An input iterator.
 168        *  @param  __last  An input iterator.
 169        *  @param  __comp  A comparison functor.
 170        *  @param  __a  An allocator object.
 171        *
 172        *  Create a %multiset consisting of copies of the elements from
 173        *  [__first,__last).  This is linear in N if the range is already sorted,
 174        *  and NlogN otherwise (where N is distance(__first,__last)).
 175        */
 176       template<typename _InputIterator>
 177         multiset(_InputIterator __first, _InputIterator __last,
 178                  const _Compare& __comp,
 179                  const allocator_type& __a = allocator_type())
 180         : _M_t(__comp, _Key_alloc_type(__a))
 181         { _M_t._M_insert_equal(__first, __last); }
 182
 183       /**
 184        *  @brief  %Multiset copy constructor.
 185        *  @param  __x  A %multiset of identical element and allocator types.
 186        *
 187        *  The newly-created %multiset uses a copy of the allocation object used
 188        *  by @a __x.
 189        */
 190       multiset(const multiset& __x)
 191       : _M_t(__x._M_t) { }
 192
 193 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 194      /**
 195        *  @brief  %Multiset move constructor.
 196        *  @param  __x  A %multiset of identical element and allocator types.
 197        *
 198        *  The newly-created %multiset contains the exact contents of @a __x.
 199        *  The contents of @a __x are a valid, but unspecified %multiset.
 200        */
 201       multiset(multiset&& __x)
 202       noexcept(is_nothrow_copy_constructible<_Compare>::value)
 203       : _M_t(std::move(__x._M_t)) { }
 204
 205       /**
 206        *  @brief  Builds a %multiset from an initializer_list.
 207        *  @param  __l  An initializer_list.
 208        *  @param  __comp  A comparison functor.
 209        *  @param  __a  An allocator object.
 210        *
 211        *  Create a %multiset consisting of copies of the elements from
 212        *  the list.  This is linear in N if the list is already sorted,
 213        *  and NlogN otherwise (where N is @a __l.size()).
 214        */
 215       multiset(initializer_list<value_type> __l,
 216                const _Compare& __comp = _Compare(),
 217                const allocator_type& __a = allocator_type())
 218       : _M_t(__comp, _Key_alloc_type(__a))
 219       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
 220 #endif
 221
 222       /**
 223        *  @brief  %Multiset assignment operator.
 224        *  @param  __x  A %multiset of identical element and allocator types.
 225        *
 226        *  All the elements of @a __x are copied, but unlike the copy
 227        *  constructor, the allocator object is not copied.
 228        */
 229       multiset&
 230       operator=(const multiset& __x)
 231       {
 232         _M_t = __x._M_t;
 233         return *this;
 234       }
 235
 236 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 237       /**
 238        *  @brief  %Multiset move assignment operator.
 239        *  @param  __x  A %multiset of identical element and allocator types.
 240        *
 241        *  The contents of @a __x are moved into this %multiset
 242        *  (without copying).  @a __x is a valid, but unspecified
 243        *  %multiset.
 244        */
 245       multiset&
 246       operator=(multiset&& __x)
 247       {
 248         // NB: DR 1204.
 249         // NB: DR 675.
 250         this->clear();
 251         this->swap(__x);
 252         return *this;
 253       }
 254
 255       /**
 256        *  @brief  %Multiset list assignment operator.
 257        *  @param  __l  An initializer_list.
 258        *
 259        *  This function fills a %multiset with copies of the elements in the
 260        *  initializer list @a __l.
 261        *
 262        *  Note that the assignment completely changes the %multiset and
 263        *  that the resulting %multiset's size is the same as the number
 264        *  of elements assigned.  Old data may be lost.
 265        */
 266       multiset&
 267       operator=(initializer_list<value_type> __l)
 268       {
 269         this->clear();
 270         this->insert(__l.begin(), __l.end());
 271         return *this;
 272       }
 273 #endif
 274
 275       // accessors:
 276
 277       ///  Returns the comparison object.
 278       key_compare
 279       key_comp() const
 280       { return _M_t.key_comp(); }
 281       ///  Returns the comparison object.
 282       value_compare
 283       value_comp() const
 284       { return _M_t.key_comp(); }
 285       ///  Returns the memory allocation object.
 286       allocator_type
 287       get_allocator() const _GLIBCXX_NOEXCEPT
 288       { return allocator_type(_M_t.get_allocator()); }
 289
 290       /**
 291        *  Returns a read-only (constant) iterator that points to the first
 292        *  element in the %multiset.  Iteration is done in ascending order
 293        *  according to the keys.
 294        */
 295       iterator
 296       begin() const _GLIBCXX_NOEXCEPT
 297       { return _M_t.begin(); }
 298
 299       /**
 300        *  Returns a read-only (constant) iterator that points one past the last
 301        *  element in the %multiset.  Iteration is done in ascending order
 302        *  according to the keys.
 303        */
 304       iterator
 305       end() const _GLIBCXX_NOEXCEPT
 306       { return _M_t.end(); }
 307
 308       /**
 309        *  Returns a read-only (constant) reverse iterator that points to the
 310        *  last element in the %multiset.  Iteration is done in descending order
 311        *  according to the keys.
 312        */
 313       reverse_iterator
 314       rbegin() const _GLIBCXX_NOEXCEPT
 315       { return _M_t.rbegin(); }
 316
 317       /**
 318        *  Returns a read-only (constant) reverse iterator that points to the
 319        *  last element in the %multiset.  Iteration is done in descending order
 320        *  according to the keys.
 321        */
 322       reverse_iterator
 323       rend() const _GLIBCXX_NOEXCEPT
 324       { return _M_t.rend(); }
 325
 326 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 327       /**
 328        *  Returns a read-only (constant) iterator that points to the first
 329        *  element in the %multiset.  Iteration is done in ascending order
 330        *  according to the keys.
 331        */
 332       iterator
 333       cbegin() const noexcept
 334       { return _M_t.begin(); }
 335
 336       /**
 337        *  Returns a read-only (constant) iterator that points one past the last
 338        *  element in the %multiset.  Iteration is done in ascending order
 339        *  according to the keys.
 340        */
 341       iterator
 342       cend() const noexcept
 343       { return _M_t.end(); }
 344
 345       /**
 346        *  Returns a read-only (constant) reverse iterator that points to the
 347        *  last element in the %multiset.  Iteration is done in descending order
 348        *  according to the keys.
 349        */
 350       reverse_iterator
 351       crbegin() const noexcept
 352       { return _M_t.rbegin(); }
 353
 354       /**
 355        *  Returns a read-only (constant) reverse iterator that points to the
 356        *  last element in the %multiset.  Iteration is done in descending order
 357        *  according to the keys.
 358        */
 359       reverse_iterator
 360       crend() const noexcept
 361       { return _M_t.rend(); }
 362 #endif
 363
 364       ///  Returns true if the %set is empty.
 365       bool
 366       empty() const _GLIBCXX_NOEXCEPT
 367       { return _M_t.empty(); }
 368
 369       ///  Returns the size of the %set.
 370       size_type
 371       size() const _GLIBCXX_NOEXCEPT
 372       { return _M_t.size(); }
 373
 374       ///  Returns the maximum size of the %set.
 375       size_type
 376       max_size() const _GLIBCXX_NOEXCEPT
 377       { return _M_t.max_size(); }
 378
 379       /**
 380        *  @brief  Swaps data with another %multiset.
 381        *  @param  __x  A %multiset of the same element and allocator types.
 382        *
 383        *  This exchanges the elements between two multisets in constant time.
 384        *  (It is only swapping a pointer, an integer, and an instance of the @c
 385        *  Compare type (which itself is often stateless and empty), so it should
 386        *  be quite fast.)
 387        *  Note that the global std::swap() function is specialized such that
 388        *  std::swap(s1,s2) will feed to this function.
 389        */
 390       void
 391       swap(multiset& __x)
 392       { _M_t.swap(__x._M_t); }
 393
 394       // insert/erase
 395 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 396       /**
 397        *  @brief Builds and inserts an element into the %multiset.
 398        *  @param  __args  Arguments used to generate the element instance to be
 399        *                 inserted.
 400        *  @return An iterator that points to the inserted element.
 401        *
 402        *  This function inserts an element into the %multiset.  Contrary
 403        *  to a std::set the %multiset does not rely on unique keys and thus
 404        *  multiple copies of the same element can be inserted.
 405        *
 406        *  Insertion requires logarithmic time.
 407        */
 408       template<typename... _Args>
 409         iterator
 410         emplace(_Args&&... __args)
 411         { return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
 412
 413       /**
 414        *  @brief Builds and inserts an element into the %multiset.
 415        *  @param  __pos  An iterator that serves as a hint as to where the
 416        *                element should be inserted.
 417        *  @param  __args  Arguments used to generate the element instance to be
 418        *                 inserted.
 419        *  @return An iterator that points to the inserted element.
 420        *
 421        *  This function inserts an element into the %multiset.  Contrary
 422        *  to a std::set the %multiset does not rely on unique keys and thus
 423        *  multiple copies of the same element can be inserted.
 424        *
 425        *  Note that the first parameter is only a hint and can potentially
 426        *  improve the performance of the insertion process.  A bad hint would
 427        *  cause no gains in efficiency.
 428        *
 429        *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
 430        *  for more on @a hinting.
 431        *
 432        *  Insertion requires logarithmic time (if the hint is not taken).
 433        */
 434       template<typename... _Args>
 435         iterator
 436         emplace_hint(const_iterator __pos, _Args&&... __args)
 437         {
 438           return _M_t._M_emplace_hint_equal(__pos,
 439                                             std::forward<_Args>(__args)...);
 440         }
 441 #endif
 442
 443       /**
 444        *  @brief Inserts an element into the %multiset.
 445        *  @param  __x  Element to be inserted.
 446        *  @return An iterator that points to the inserted element.
 447        *
 448        *  This function inserts an element into the %multiset.  Contrary
 449        *  to a std::set the %multiset does not rely on unique keys and thus
 450        *  multiple copies of the same element can be inserted.
 451        *
 452        *  Insertion requires logarithmic time.
 453        */
 454       iterator
 455       insert(const value_type& __x)
 456       { return _M_t._M_insert_equal(__x); }
 457
 458 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 459       iterator
 460       insert(value_type&& __x)
 461       { return _M_t._M_insert_equal(std::move(__x)); }
 462 #endif
 463
 464       /**
 465        *  @brief Inserts an element into the %multiset.
 466        *  @param  __position  An iterator that serves as a hint as to where the
 467        *                    element should be inserted.
 468        *  @param  __x  Element to be inserted.
 469        *  @return An iterator that points to the inserted element.
 470        *
 471        *  This function inserts an element into the %multiset.  Contrary
 472        *  to a std::set the %multiset does not rely on unique keys and thus
 473        *  multiple copies of the same element can be inserted.
 474        *
 475        *  Note that the first parameter is only a hint and can potentially
 476        *  improve the performance of the insertion process.  A bad hint would
 477        *  cause no gains in efficiency.
 478        *
 479        *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
 480        *  for more on @a hinting.
 481        *
 482        *  Insertion requires logarithmic time (if the hint is not taken).
 483        */
 484       iterator
 485       insert(const_iterator __position, const value_type& __x)
 486       { return _M_t._M_insert_equal_(__position, __x); }
 487
 488 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 489       iterator
 490       insert(const_iterator __position, value_type&& __x)
 491       { return _M_t._M_insert_equal_(__position, std::move(__x)); }
 492 #endif
 493
 494       /**
 495        *  @brief A template function that tries to insert a range of elements.
 496        *  @param  __first  Iterator pointing to the start of the range to be
 497        *                   inserted.
 498        *  @param  __last  Iterator pointing to the end of the range.
 499        *
 500        *  Complexity similar to that of the range constructor.
 501        */
 502       template<typename _InputIterator>
 503         void
 504         insert(_InputIterator __first, _InputIterator __last)
 505         { _M_t._M_insert_equal(__first, __last); }
 506
 507 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 508       /**
 509        *  @brief Attempts to insert a list of elements into the %multiset.
 510        *  @param  __l  A std::initializer_list<value_type> of elements
 511        *               to be inserted.
 512        *
 513        *  Complexity similar to that of the range constructor.
 514        */
 515       void
 516       insert(initializer_list<value_type> __l)
 517       { this->insert(__l.begin(), __l.end()); }
 518 #endif
 519
 520 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 521       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 522       // DR 130. Associative erase should return an iterator.
 523       /**
 524        *  @brief Erases an element from a %multiset.
 525        *  @param  __position  An iterator pointing to the element to be erased.
 526        *  @return An iterator pointing to the element immediately following
 527        *          @a position prior to the element being erased. If no such
 528        *          element exists, end() is returned.
 529        *
 530        *  This function erases an element, pointed to by the given iterator,
 531        *  from a %multiset.  Note that this function only erases the element,
 532        *  and that if the element is itself a pointer, the pointed-to memory is
 533        *  not touched in any way.  Managing the pointer is the user's
 534        *  responsibility.
 535        */
 536       iterator
 537       erase(const_iterator __position)
 538       { return _M_t.erase(__position); }
 539 #else
 540       /**
 541        *  @brief Erases an element from a %multiset.
 542        *  @param  __position  An iterator pointing to the element to be erased.
 543        *
 544        *  This function erases an element, pointed to by the given iterator,
 545        *  from a %multiset.  Note that this function only erases the element,
 546        *  and that if the element is itself a pointer, the pointed-to memory is
 547        *  not touched in any way.  Managing the pointer is the user's
 548        *  responsibility.
 549        */
 550       void
 551       erase(iterator __position)
 552       { _M_t.erase(__position); }
 553 #endif
 554
 555       /**
 556        *  @brief Erases elements according to the provided key.
 557        *  @param  __x  Key of element to be erased.
 558        *  @return  The number of elements erased.
 559        *
 560        *  This function erases all elements located by the given key from a
 561        *  %multiset.
 562        *  Note that this function only erases the element, and that if
 563        *  the element is itself a pointer, the pointed-to memory is not touched
 564        *  in any way.  Managing the pointer is the user's responsibility.
 565        */
 566       size_type
 567       erase(const key_type& __x)
 568       { return _M_t.erase(__x); }
 569
 570 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 571       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 572       // DR 130. Associative erase should return an iterator.
 573       /**
 574        *  @brief Erases a [first,last) range of elements from a %multiset.
 575        *  @param  __first  Iterator pointing to the start of the range to be
 576        *                   erased.
 577        *  @param __last Iterator pointing to the end of the range to
 578        *                be erased.
 579        *  @return The iterator @a last.
 580        *
 581        *  This function erases a sequence of elements from a %multiset.
 582        *  Note that this function only erases the elements, and that if
 583        *  the elements themselves are pointers, the pointed-to memory is not
 584        *  touched in any way.  Managing the pointer is the user's
 585        *  responsibility.
 586        */
 587       iterator
 588       erase(const_iterator __first, const_iterator __last)
 589       { return _M_t.erase(__first, __last); }
 590 #else
 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 be erased.
 596        *
 597        *  This function erases a sequence of elements from a %multiset.
 598        *  Note that this function only erases the elements, and that if
 599        *  the elements themselves are pointers, the pointed-to memory is not
 600        *  touched in any way.  Managing the pointer is the user's
 601        *  responsibility.
 602        */
 603       void
 604       erase(iterator __first, iterator __last)
 605       { _M_t.erase(__first, __last); }
 606 #endif
 607
 608       /**
 609        *  Erases all elements in a %multiset.  Note that this function only
 610        *  erases the elements, and that if the elements themselves are pointers,
 611        *  the pointed-to memory is not touched in any way.  Managing the pointer
 612        *  is the user's responsibility.
 613        */
 614       void
 615       clear() _GLIBCXX_NOEXCEPT
 616       { _M_t.clear(); }
 617
 618       // multiset operations:
 619
 620       /**
 621        *  @brief Finds the number of elements with given key.
 622        *  @param  __x  Key of elements to be located.
 623        *  @return Number of elements with specified key.
 624        */
 625       size_type
 626       count(const key_type& __x) const
 627       { return _M_t.count(__x); }
 628
 629       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 630       // 214.  set::find() missing const overload
 631       //@{
 632       /**
 633        *  @brief Tries to locate an element in a %set.
 634        *  @param  __x  Element to be located.
 635        *  @return  Iterator pointing to sought-after element, or end() if not
 636        *           found.
 637        *
 638        *  This function takes a key and tries to locate the element with which
 639        *  the key matches.  If successful the function returns an iterator
 640        *  pointing to the sought after element.  If unsuccessful it returns the
 641        *  past-the-end ( @c end() ) iterator.
 642        */
 643       iterator
 644       find(const key_type& __x)
 645       { return _M_t.find(__x); }
 646
 647       const_iterator
 648       find(const key_type& __x) const
 649       { return _M_t.find(__x); }
 650       //@}
 651
 652       //@{
 653       /**
 654        *  @brief Finds the beginning of a subsequence matching given key.
 655        *  @param  __x  Key to be located.
 656        *  @return  Iterator pointing to first element equal to or greater
 657        *           than key, or end().
 658        *
 659        *  This function returns the first element of a subsequence of elements
 660        *  that matches the given key.  If unsuccessful it returns an iterator
 661        *  pointing to the first element that has a greater value than given key
 662        *  or end() if no such element exists.
 663        */
 664       iterator
 665       lower_bound(const key_type& __x)
 666       { return _M_t.lower_bound(__x); }
 667
 668       const_iterator
 669       lower_bound(const key_type& __x) const
 670       { return _M_t.lower_bound(__x); }
 671       //@}
 672
 673       //@{
 674       /**
 675        *  @brief Finds the end of a subsequence matching given key.
 676        *  @param  __x  Key to be located.
 677        *  @return Iterator pointing to the first element
 678        *          greater than key, or end().
 679        */
 680       iterator
 681       upper_bound(const key_type& __x)
 682       { return _M_t.upper_bound(__x); }
 683
 684       const_iterator
 685       upper_bound(const key_type& __x) const
 686       { return _M_t.upper_bound(__x); }
 687       //@}
 688
 689       //@{
 690       /**
 691        *  @brief Finds a subsequence matching given key.
 692        *  @param  __x  Key to be located.
 693        *  @return  Pair of iterators that possibly points to the subsequence
 694        *           matching given key.
 695        *
 696        *  This function is equivalent to
 697        *  @code
 698        *    std::make_pair(c.lower_bound(val),
 699        *                   c.upper_bound(val))
 700        *  @endcode
 701        *  (but is faster than making the calls separately).
 702        *
 703        *  This function probably only makes sense for multisets.
 704        */
 705       std::pair<iterator, iterator>
 706       equal_range(const key_type& __x)
 707       { return _M_t.equal_range(__x); }
 708
 709       std::pair<const_iterator, const_iterator>
 710       equal_range(const key_type& __x) const
 711       { return _M_t.equal_range(__x); }
 712       //@}
 713
 714       template<typename _K1, typename _C1, typename _A1>
 715         friend bool
 716         operator==(const multiset<_K1, _C1, _A1>&,
 717                    const multiset<_K1, _C1, _A1>&);
 718
 719       template<typename _K1, typename _C1, typename _A1>
 720         friend bool
 721         operator< (const multiset<_K1, _C1, _A1>&,
 722                    const multiset<_K1, _C1, _A1>&);
 723     };
 724
 725   /**
 726    *  @brief  Multiset equality comparison.
 727    *  @param  __x  A %multiset.
 728    *  @param  __y  A %multiset of the same type as @a __x.
 729    *  @return  True iff the size and elements of the multisets are equal.
 730    *
 731    *  This is an equivalence relation.  It is linear in the size of the
 732    *  multisets.
 733    *  Multisets are considered equivalent if their sizes are equal, and if
 734    *  corresponding elements compare equal.
 735   */
 736   template<typename _Key, typename _Compare, typename _Alloc>
 737     inline bool
 738     operator==(const multiset<_Key, _Compare, _Alloc>& __x,
 739                const multiset<_Key, _Compare, _Alloc>& __y)
 740     { return __x._M_t == __y._M_t; }
 741
 742   /**
 743    *  @brief  Multiset ordering relation.
 744    *  @param  __x  A %multiset.
 745    *  @param  __y  A %multiset of the same type as @a __x.
 746    *  @return  True iff @a __x is lexicographically less than @a __y.
 747    *
 748    *  This is a total ordering relation.  It is linear in the size of the
 749    *  maps.  The elements must be comparable with @c <.
 750    *
 751    *  See std::lexicographical_compare() for how the determination is made.
 752   */
 753   template<typename _Key, typename _Compare, typename _Alloc>
 754     inline bool
 755     operator<(const multiset<_Key, _Compare, _Alloc>& __x,
 756               const multiset<_Key, _Compare, _Alloc>& __y)
 757     { return __x._M_t < __y._M_t; }
 758
 759   ///  Returns !(x == y).
 760   template<typename _Key, typename _Compare, typename _Alloc>
 761     inline bool
 762     operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
 763                const multiset<_Key, _Compare, _Alloc>& __y)
 764     { return !(__x == __y); }
 765
 766   ///  Returns y < x.
 767   template<typename _Key, typename _Compare, typename _Alloc>
 768     inline bool
 769     operator>(const multiset<_Key,_Compare,_Alloc>& __x,
 770               const multiset<_Key,_Compare,_Alloc>& __y)
 771     { return __y < __x; }
 772
 773   ///  Returns !(y < x)
 774   template<typename _Key, typename _Compare, typename _Alloc>
 775     inline bool
 776     operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
 777                const multiset<_Key, _Compare, _Alloc>& __y)
 778     { return !(__y < __x); }
 779
 780   ///  Returns !(x < y)
 781   template<typename _Key, typename _Compare, typename _Alloc>
 782     inline bool
 783     operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
 784                const multiset<_Key, _Compare, _Alloc>& __y)
 785     { return !(__x < __y); }
 786
 787   /// See std::multiset::swap().
 788   template<typename _Key, typename _Compare, typename _Alloc>
 789     inline void
 790     swap(multiset<_Key, _Compare, _Alloc>& __x,
 791          multiset<_Key, _Compare, _Alloc>& __y)
 792     { __x.swap(__y); }
 793
 794 _GLIBCXX_END_NAMESPACE_CONTAINER
 795 } // namespace std
 796
 797 #endif /* _STL_MULTISET_H */