1// Set 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) 1996,1997
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_set.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_SET_H
58#define _STL_SET_H 1
59
60#include <bits/concept_check.h>
61#ifdef __GXX_EXPERIMENTAL_CXX0X__
62#include <initializer_list>
63#endif
64
65namespace std _GLIBCXX_VISIBILITY(default)
66{
67_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
68
69  /**
70   *  @brief A standard container made up of unique keys, which can be
71   *  retrieved 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 unique keys).
78   *
79   *  Sets support bidirectional iterators.
80   *
81   *  @tparam  _Key  Type of key objects.
82   *  @tparam  _Compare  Comparison function object type, defaults to less<Key>.
83   *  @tparam  _Alloc  Allocator type, defaults to allocator<Key>.
84   *
85   *  The private tree data is declared exactly the same way for set and
86   *  multiset; the distinction is made entirely in how the tree functions are
87   *  called (*_unique versus *_equal, same as the standard).
88  */
89  template<typename _Key, typename _Compare = std::less<_Key>,
90	   typename _Alloc = std::allocator<_Key> >
91    class set
92    {
93      // concept requirements
94      typedef typename _Alloc::value_type                   _Alloc_value_type;
95      __glibcxx_class_requires(_Key, _SGIAssignableConcept)
96      __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
97				_BinaryFunctionConcept)
98      __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
99
100    public:
101      // typedefs:
102      //@{
103      /// Public 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
111    private:
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      _Rep_type _M_t;  // Red-black tree representing set.
117
118    public:
119      //@{
120      ///  Iterator-related typedefs.
121      typedef typename _Key_alloc_type::pointer             pointer;
122      typedef typename _Key_alloc_type::const_pointer       const_pointer;
123      typedef typename _Key_alloc_type::reference           reference;
124      typedef typename _Key_alloc_type::const_reference     const_reference;
125      // _GLIBCXX_RESOLVE_LIB_DEFECTS
126      // DR 103. set::iterator is required to be modifiable,
127      // but this allows modification of keys.
128      typedef typename _Rep_type::const_iterator            iterator;
129      typedef typename _Rep_type::const_iterator            const_iterator;
130      typedef typename _Rep_type::const_reverse_iterator    reverse_iterator;
131      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
132      typedef typename _Rep_type::size_type                 size_type;
133      typedef typename _Rep_type::difference_type           difference_type;
134      //@}
135
136      // allocation/deallocation
137      /**
138       *  @brief  Default constructor creates no elements.
139       */
140      set()
141      : _M_t() { }
142
143      /**
144       *  @brief  Creates a %set with no elements.
145       *  @param  __comp  Comparator to use.
146       *  @param  __a  An allocator object.
147       */
148      explicit
149      set(const _Compare& __comp,
150	  const allocator_type& __a = allocator_type())
151      : _M_t(__comp, _Key_alloc_type(__a)) { }
152
153      /**
154       *  @brief  Builds a %set from a range.
155       *  @param  __first  An input iterator.
156       *  @param  __last  An input iterator.
157       *
158       *  Create a %set consisting of copies of the elements from
159       *  [__first,__last).  This is linear in N if the range is
160       *  already sorted, and NlogN otherwise (where N is
161       *  distance(__first,__last)).
162       */
163      template<typename _InputIterator>
164	set(_InputIterator __first, _InputIterator __last)
165	: _M_t()
166	{ _M_t._M_insert_unique(__first, __last); }
167
168      /**
169       *  @brief  Builds a %set from a range.
170       *  @param  __first  An input iterator.
171       *  @param  __last  An input iterator.
172       *  @param  __comp  A comparison functor.
173       *  @param  __a  An allocator object.
174       *
175       *  Create a %set consisting of copies of the elements from
176       *  [__first,__last).  This is linear in N if the range is
177       *  already sorted, and NlogN otherwise (where N is
178       *  distance(__first,__last)).
179       */
180      template<typename _InputIterator>
181	set(_InputIterator __first, _InputIterator __last,
182	    const _Compare& __comp,
183	    const allocator_type& __a = allocator_type())
184	: _M_t(__comp, _Key_alloc_type(__a))
185        { _M_t._M_insert_unique(__first, __last); }
186
187      /**
188       *  @brief  %Set copy constructor.
189       *  @param  __x  A %set of identical element and allocator types.
190       *
191       *  The newly-created %set uses a copy of the allocation object used
192       *  by @a __x.
193       */
194      set(const set& __x)
195      : _M_t(__x._M_t) { }
196
197#ifdef __GXX_EXPERIMENTAL_CXX0X__
198     /**
199       *  @brief %Set move constructor
200       *  @param __x  A %set of identical element and allocator types.
201       *
202       *  The newly-created %set contains the exact contents of @a x.
203       *  The contents of @a x are a valid, but unspecified %set.
204       */
205      set(set&& __x)
206      noexcept(is_nothrow_copy_constructible<_Compare>::value)
207      : _M_t(std::move(__x._M_t)) { }
208
209      /**
210       *  @brief  Builds a %set from an initializer_list.
211       *  @param  __l  An initializer_list.
212       *  @param  __comp  A comparison functor.
213       *  @param  __a  An allocator object.
214       *
215       *  Create a %set consisting of copies of the elements in the list.
216       *  This is linear in N if the list is already sorted, and NlogN
217       *  otherwise (where N is @a __l.size()).
218       */
219      set(initializer_list<value_type> __l,
220	  const _Compare& __comp = _Compare(),
221	  const allocator_type& __a = allocator_type())
222      : _M_t(__comp, _Key_alloc_type(__a))
223      { _M_t._M_insert_unique(__l.begin(), __l.end()); }
224#endif
225
226      /**
227       *  @brief  %Set assignment operator.
228       *  @param  __x  A %set of identical element and allocator types.
229       *
230       *  All the elements of @a __x are copied, but unlike the copy
231       *  constructor, the allocator object is not copied.
232       */
233      set&
234      operator=(const set& __x)
235      {
236	_M_t = __x._M_t;
237	return *this;
238      }
239
240#ifdef __GXX_EXPERIMENTAL_CXX0X__
241      /**
242       *  @brief %Set move assignment operator.
243       *  @param __x  A %set of identical element and allocator types.
244       *
245       *  The contents of @a __x are moved into this %set (without copying).
246       *  @a __x is a valid, but unspecified %set.
247       */
248      set&
249      operator=(set&& __x)
250      {
251	// NB: DR 1204.
252	// NB: DR 675.
253	this->clear();
254	this->swap(__x);
255      	return *this;
256      }
257
258      /**
259       *  @brief  %Set list assignment operator.
260       *  @param  __l  An initializer_list.
261       *
262       *  This function fills a %set with copies of the elements in the
263       *  initializer list @a __l.
264       *
265       *  Note that the assignment completely changes the %set and
266       *  that the resulting %set's size is the same as the number
267       *  of elements assigned.  Old data may be lost.
268       */
269      set&
270      operator=(initializer_list<value_type> __l)
271      {
272	this->clear();
273	this->insert(__l.begin(), __l.end());
274	return *this;
275      }
276#endif
277
278      // accessors:
279
280      ///  Returns the comparison object with which the %set was constructed.
281      key_compare
282      key_comp() const
283      { return _M_t.key_comp(); }
284      ///  Returns the comparison object with which the %set was constructed.
285      value_compare
286      value_comp() const
287      { return _M_t.key_comp(); }
288      ///  Returns the allocator object with which the %set was constructed.
289      allocator_type
290      get_allocator() const _GLIBCXX_NOEXCEPT
291      { return allocator_type(_M_t.get_allocator()); }
292
293      /**
294       *  Returns a read-only (constant) iterator that points to the first
295       *  element in the %set.  Iteration is done in ascending order according
296       *  to the keys.
297       */
298      iterator
299      begin() const _GLIBCXX_NOEXCEPT
300      { return _M_t.begin(); }
301
302      /**
303       *  Returns a read-only (constant) iterator that points one past the last
304       *  element in the %set.  Iteration is done in ascending order according
305       *  to the keys.
306       */
307      iterator
308      end() const _GLIBCXX_NOEXCEPT
309      { return _M_t.end(); }
310
311      /**
312       *  Returns a read-only (constant) iterator that points to the last
313       *  element in the %set.  Iteration is done in descending order according
314       *  to the keys.
315       */
316      reverse_iterator
317      rbegin() const _GLIBCXX_NOEXCEPT
318      { return _M_t.rbegin(); }
319
320      /**
321       *  Returns a read-only (constant) reverse iterator that points to the
322       *  last pair in the %set.  Iteration is done in descending order
323       *  according to the keys.
324       */
325      reverse_iterator
326      rend() const _GLIBCXX_NOEXCEPT
327      { return _M_t.rend(); }
328
329#ifdef __GXX_EXPERIMENTAL_CXX0X__
330      /**
331       *  Returns a read-only (constant) iterator that points to the first
332       *  element in the %set.  Iteration is done in ascending order according
333       *  to the keys.
334       */
335      iterator
336      cbegin() const noexcept
337      { return _M_t.begin(); }
338
339      /**
340       *  Returns a read-only (constant) iterator that points one past the last
341       *  element in the %set.  Iteration is done in ascending order according
342       *  to the keys.
343       */
344      iterator
345      cend() const noexcept
346      { return _M_t.end(); }
347
348      /**
349       *  Returns a read-only (constant) iterator that points to the last
350       *  element in the %set.  Iteration is done in descending order according
351       *  to the keys.
352       */
353      reverse_iterator
354      crbegin() const noexcept
355      { return _M_t.rbegin(); }
356
357      /**
358       *  Returns a read-only (constant) reverse iterator that points to the
359       *  last pair in the %set.  Iteration is done in descending order
360       *  according to the keys.
361       */
362      reverse_iterator
363      crend() const noexcept
364      { return _M_t.rend(); }
365#endif
366
367      ///  Returns true if the %set is empty.
368      bool
369      empty() const _GLIBCXX_NOEXCEPT
370      { return _M_t.empty(); }
371
372      ///  Returns the size of the %set.
373      size_type
374      size() const _GLIBCXX_NOEXCEPT
375      { return _M_t.size(); }
376
377      ///  Returns the maximum size of the %set.
378      size_type
379      max_size() const _GLIBCXX_NOEXCEPT
380      { return _M_t.max_size(); }
381
382      /**
383       *  @brief  Swaps data with another %set.
384       *  @param  __x  A %set of the same element and allocator types.
385       *
386       *  This exchanges the elements between two sets in constant
387       *  time.  (It is only swapping a pointer, an integer, and an
388       *  instance of the @c Compare type (which itself is often
389       *  stateless and empty), so it should be quite fast.)  Note
390       *  that the global std::swap() function is specialized such
391       *  that std::swap(s1,s2) will feed to this function.
392       */
393      void
394      swap(set& __x)
395      { _M_t.swap(__x._M_t); }
396
397      // insert/erase
398      /**
399       *  @brief Attempts to insert an element into the %set.
400       *  @param  __x  Element to be inserted.
401       *  @return  A pair, of which the first element is an iterator that points
402       *           to the possibly inserted element, and the second is a bool
403       *           that is true if the element was actually inserted.
404       *
405       *  This function attempts to insert an element into the %set.  A %set
406       *  relies on unique keys and thus an element is only inserted if it is
407       *  not already present in the %set.
408       *
409       *  Insertion requires logarithmic time.
410       */
411      std::pair<iterator, bool>
412      insert(const value_type& __x)
413      {
414	std::pair<typename _Rep_type::iterator, bool> __p =
415	  _M_t._M_insert_unique(__x);
416	return std::pair<iterator, bool>(__p.first, __p.second);
417      }
418
419#ifdef __GXX_EXPERIMENTAL_CXX0X__
420      std::pair<iterator, bool>
421      insert(value_type&& __x)
422      {
423	std::pair<typename _Rep_type::iterator, bool> __p =
424	  _M_t._M_insert_unique(std::move(__x));
425	return std::pair<iterator, bool>(__p.first, __p.second);
426      }
427#endif
428
429      /**
430       *  @brief Attempts to insert an element into the %set.
431       *  @param  __position  An iterator that serves as a hint as to where the
432       *                    element should be inserted.
433       *  @param  __x  Element to be inserted.
434       *  @return An iterator that points to the element with key of
435       *           @a __x (may or may not be the element passed in).
436       *
437       *  This function is not concerned about whether the insertion took place,
438       *  and thus does not return a boolean like the single-argument insert()
439       *  does.  Note that the first parameter is only a hint and can
440       *  potentially improve the performance of the insertion process.  A bad
441       *  hint would cause no gains in efficiency.
442       *
443       *  For more on @a hinting, see:
444       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
445       *
446       *  Insertion requires logarithmic time (if the hint is not taken).
447       */
448      iterator
449      insert(const_iterator __position, const value_type& __x)
450      { return _M_t._M_insert_unique_(__position, __x); }
451
452#ifdef __GXX_EXPERIMENTAL_CXX0X__
453      iterator
454      insert(const_iterator __position, value_type&& __x)
455      { return _M_t._M_insert_unique_(__position, std::move(__x)); }
456#endif
457
458      /**
459       *  @brief A template function that attempts to insert a range
460       *  of elements.
461       *  @param  __first  Iterator pointing to the start of the range to be
462       *                   inserted.
463       *  @param  __last  Iterator pointing to the end of the range.
464       *
465       *  Complexity similar to that of the range constructor.
466       */
467      template<typename _InputIterator>
468	void
469	insert(_InputIterator __first, _InputIterator __last)
470	{ _M_t._M_insert_unique(__first, __last); }
471
472#ifdef __GXX_EXPERIMENTAL_CXX0X__
473      /**
474       *  @brief Attempts to insert a list of elements into the %set.
475       *  @param  __l  A std::initializer_list<value_type> of elements
476       *               to be inserted.
477       *
478       *  Complexity similar to that of the range constructor.
479       */
480      void
481      insert(initializer_list<value_type> __l)
482      { this->insert(__l.begin(), __l.end()); }
483#endif
484
485#ifdef __GXX_EXPERIMENTAL_CXX0X__
486      // _GLIBCXX_RESOLVE_LIB_DEFECTS
487      // DR 130. Associative erase should return an iterator.
488      /**
489       *  @brief Erases an element from a %set.
490       *  @param  __position  An iterator pointing to the element to be erased.
491       *  @return An iterator pointing to the element immediately following
492       *          @a __position prior to the element being erased. If no such
493       *          element exists, end() is returned.
494       *
495       *  This function erases an element, pointed to by the given iterator,
496       *  from a %set.  Note that this function only erases the element, and
497       *  that if the element is itself a pointer, the pointed-to memory is not
498       *  touched in any way.  Managing the pointer is the user's
499       *  responsibility.
500       */
501      iterator
502      erase(const_iterator __position)
503      { return _M_t.erase(__position); }
504#else
505      /**
506       *  @brief Erases an element from a %set.
507       *  @param  position  An iterator pointing to the element to be erased.
508       *
509       *  This function erases an element, pointed to by the given iterator,
510       *  from a %set.  Note that this function only erases the element, and
511       *  that if the element is itself a pointer, the pointed-to memory is not
512       *  touched in any way.  Managing the pointer is the user's
513       *  responsibility.
514       */
515      void
516      erase(iterator __position)
517      { _M_t.erase(__position); }
518#endif
519
520      /**
521       *  @brief Erases elements according to the provided key.
522       *  @param  __x  Key of element to be erased.
523       *  @return  The number of elements erased.
524       *
525       *  This function erases all the elements located by the given key from
526       *  a %set.
527       *  Note that this function only erases the element, and that if
528       *  the element is itself a pointer, the pointed-to memory is not touched
529       *  in any way.  Managing the pointer is the user's responsibility.
530       */
531      size_type
532      erase(const key_type& __x)
533      { return _M_t.erase(__x); }
534
535#ifdef __GXX_EXPERIMENTAL_CXX0X__
536      // _GLIBCXX_RESOLVE_LIB_DEFECTS
537      // DR 130. Associative erase should return an iterator.
538      /**
539       *  @brief Erases a [__first,__last) range of elements from a %set.
540       *  @param  __first  Iterator pointing to the start of the range to be
541       *                 erased.
542
543       *  @param __last Iterator pointing to the end of the range to
544       *  be erased.
545       *  @return The iterator @a __last.
546       *
547       *  This function erases a sequence of elements from a %set.
548       *  Note that this function only erases the element, and that if
549       *  the element is itself a pointer, the pointed-to memory is not touched
550       *  in any way.  Managing the pointer is the user's responsibility.
551       */
552      iterator
553      erase(const_iterator __first, const_iterator __last)
554      { return _M_t.erase(__first, __last); }
555#else
556      /**
557       *  @brief Erases a [first,last) range of elements from a %set.
558       *  @param  __first  Iterator pointing to the start of the range to be
559       *                 erased.
560       *  @param __last Iterator pointing to the end of the range to
561       *  be erased.
562       *
563       *  This function erases a sequence of elements from a %set.
564       *  Note that this function only erases the element, and that if
565       *  the element is itself a pointer, the pointed-to memory is not touched
566       *  in any way.  Managing the pointer is the user's responsibility.
567       */
568      void
569      erase(iterator __first, iterator __last)
570      { _M_t.erase(__first, __last); }
571#endif
572
573      /**
574       *  Erases all elements in a %set.  Note that this function only erases
575       *  the elements, and that if the elements themselves are pointers, the
576       *  pointed-to memory is not touched in any way.  Managing the pointer is
577       *  the user's responsibility.
578       */
579      void
580      clear() _GLIBCXX_NOEXCEPT
581      { _M_t.clear(); }
582
583      // set operations:
584
585      /**
586       *  @brief  Finds the number of elements.
587       *  @param  __x  Element to located.
588       *  @return  Number of elements with specified key.
589       *
590       *  This function only makes sense for multisets; for set the result will
591       *  either be 0 (not present) or 1 (present).
592       */
593      size_type
594      count(const key_type& __x) const
595      { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
596
597      // _GLIBCXX_RESOLVE_LIB_DEFECTS
598      // 214.  set::find() missing const overload
599      //@{
600      /**
601       *  @brief Tries to locate an element in a %set.
602       *  @param  __x  Element to be located.
603       *  @return  Iterator pointing to sought-after element, or end() if not
604       *           found.
605       *
606       *  This function takes a key and tries to locate the element with which
607       *  the key matches.  If successful the function returns an iterator
608       *  pointing to the sought after element.  If unsuccessful it returns the
609       *  past-the-end ( @c end() ) iterator.
610       */
611      iterator
612      find(const key_type& __x)
613      { return _M_t.find(__x); }
614
615      const_iterator
616      find(const key_type& __x) const
617      { return _M_t.find(__x); }
618      //@}
619
620      //@{
621      /**
622       *  @brief Finds the beginning of a subsequence matching given key.
623       *  @param  __x  Key to be located.
624       *  @return  Iterator pointing to first element equal to or greater
625       *           than key, or end().
626       *
627       *  This function returns the first element of a subsequence of elements
628       *  that matches the given key.  If unsuccessful it returns an iterator
629       *  pointing to the first element that has a greater value than given key
630       *  or end() if no such element exists.
631       */
632      iterator
633      lower_bound(const key_type& __x)
634      { return _M_t.lower_bound(__x); }
635
636      const_iterator
637      lower_bound(const key_type& __x) const
638      { return _M_t.lower_bound(__x); }
639      //@}
640
641      //@{
642      /**
643       *  @brief Finds the end of a subsequence matching given key.
644       *  @param  __x  Key to be located.
645       *  @return Iterator pointing to the first element
646       *          greater than key, or end().
647       */
648      iterator
649      upper_bound(const key_type& __x)
650      { return _M_t.upper_bound(__x); }
651
652      const_iterator
653      upper_bound(const key_type& __x) const
654      { return _M_t.upper_bound(__x); }
655      //@}
656
657      //@{
658      /**
659       *  @brief Finds a subsequence matching given key.
660       *  @param  __x  Key to be located.
661       *  @return  Pair of iterators that possibly points to the subsequence
662       *           matching given key.
663       *
664       *  This function is equivalent to
665       *  @code
666       *    std::make_pair(c.lower_bound(val),
667       *                   c.upper_bound(val))
668       *  @endcode
669       *  (but is faster than making the calls separately).
670       *
671       *  This function probably only makes sense for multisets.
672       */
673      std::pair<iterator, iterator>
674      equal_range(const key_type& __x)
675      { return _M_t.equal_range(__x); }
676
677      std::pair<const_iterator, const_iterator>
678      equal_range(const key_type& __x) const
679      { return _M_t.equal_range(__x); }
680      //@}
681
682      template<typename _K1, typename _C1, typename _A1>
683	friend bool
684	operator==(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
685
686      template<typename _K1, typename _C1, typename _A1>
687	friend bool
688	operator<(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
689    };
690
691
692  /**
693   *  @brief  Set equality comparison.
694   *  @param  __x  A %set.
695   *  @param  __y  A %set of the same type as @a x.
696   *  @return  True iff the size and elements of the sets are equal.
697   *
698   *  This is an equivalence relation.  It is linear in the size of the sets.
699   *  Sets are considered equivalent if their sizes are equal, and if
700   *  corresponding elements compare equal.
701  */
702  template<typename _Key, typename _Compare, typename _Alloc>
703    inline bool
704    operator==(const set<_Key, _Compare, _Alloc>& __x,
705	       const set<_Key, _Compare, _Alloc>& __y)
706    { return __x._M_t == __y._M_t; }
707
708  /**
709   *  @brief  Set ordering relation.
710   *  @param  __x  A %set.
711   *  @param  __y  A %set of the same type as @a x.
712   *  @return  True iff @a __x is lexicographically less than @a __y.
713   *
714   *  This is a total ordering relation.  It is linear in the size of the
715   *  maps.  The elements must be comparable with @c <.
716   *
717   *  See std::lexicographical_compare() for how the determination is made.
718  */
719  template<typename _Key, typename _Compare, typename _Alloc>
720    inline bool
721    operator<(const set<_Key, _Compare, _Alloc>& __x,
722	      const set<_Key, _Compare, _Alloc>& __y)
723    { return __x._M_t < __y._M_t; }
724
725  ///  Returns !(x == y).
726  template<typename _Key, typename _Compare, typename _Alloc>
727    inline bool
728    operator!=(const set<_Key, _Compare, _Alloc>& __x,
729	       const set<_Key, _Compare, _Alloc>& __y)
730    { return !(__x == __y); }
731
732  ///  Returns y < x.
733  template<typename _Key, typename _Compare, typename _Alloc>
734    inline bool
735    operator>(const set<_Key, _Compare, _Alloc>& __x,
736	      const set<_Key, _Compare, _Alloc>& __y)
737    { return __y < __x; }
738
739  ///  Returns !(y < x)
740  template<typename _Key, typename _Compare, typename _Alloc>
741    inline bool
742    operator<=(const set<_Key, _Compare, _Alloc>& __x,
743	       const set<_Key, _Compare, _Alloc>& __y)
744    { return !(__y < __x); }
745
746  ///  Returns !(x < y)
747  template<typename _Key, typename _Compare, typename _Alloc>
748    inline bool
749    operator>=(const set<_Key, _Compare, _Alloc>& __x,
750	       const set<_Key, _Compare, _Alloc>& __y)
751    { return !(__x < __y); }
752
753  /// See std::set::swap().
754  template<typename _Key, typename _Compare, typename _Alloc>
755    inline void
756    swap(set<_Key, _Compare, _Alloc>& __x, set<_Key, _Compare, _Alloc>& __y)
757    { __x.swap(__y); }
758
759_GLIBCXX_END_NAMESPACE_CONTAINER
760} //namespace std
761#endif /* _STL_SET_H */
762