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

   1 // hashtable.h header -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /** @file bits/hashtable.h
  26  *  This is an internal header file, included by other library headers.
  27  *  You should not attempt to use it directly.
  28  */
  29
  30 #ifndef _HASHTABLE_H
  31 #define _HASHTABLE_H 1
  32
  33 #pragma GCC system_header
  34
  35 #include <bits/hashtable_policy.h>
  36
  37 namespace std
  38 {
  39   // Class template _Hashtable, class definition.
  40
  41   // Meaning of class template _Hashtable's template parameters
  42
  43   // _Key and _Value: arbitrary CopyConstructible types.
  44
  45   // _Allocator: an allocator type ([lib.allocator.requirements]) whose
  46   // value type is Value.  As a conforming extension, we allow for
  47   // value type != Value.
  48
  49   // _ExtractKey: function object that takes a object of type Value
  50   // and returns a value of type _Key.
  51
  52   // _Equal: function object that takes two objects of type k and returns
  53   // a bool-like value that is true if the two objects are considered equal.
  54
  55   // _H1: the hash function.  A unary function object with argument type
  56   // Key and result type size_t.  Return values should be distributed
  57   // over the entire range [0, numeric_limits<size_t>:::max()].
  58
  59   // _H2: the range-hashing function (in the terminology of Tavori and
  60   // Dreizin).  A binary function object whose argument types and result
  61   // type are all size_t.  Given arguments r and N, the return value is
  62   // in the range [0, N).
  63
  64   // _Hash: the ranged hash function (Tavori and Dreizin). A binary function
  65   // whose argument types are _Key and size_t and whose result type is
  66   // size_t.  Given arguments k and N, the return value is in the range
  67   // [0, N).  Default: hash(k, N) = h2(h1(k), N).  If _Hash is anything other
  68   // than the default, _H1 and _H2 are ignored.
  69
  70   // _RehashPolicy: Policy class with three members, all of which govern
  71   // the bucket count. _M_next_bkt(n) returns a bucket count no smaller
  72   // than n.  _M_bkt_for_elements(n) returns a bucket count appropriate
  73   // for an element count of n.  _M_need_rehash(n_bkt, n_elt, n_ins)
  74   // determines whether, if the current bucket count is n_bkt and the
  75   // current element count is n_elt, we need to increase the bucket
  76   // count.  If so, returns make_pair(true, n), where n is the new
  77   // bucket count.  If not, returns make_pair(false, <anything>).
  78
  79   // ??? Right now it is hard-wired that the number of buckets never
  80   // shrinks.  Should we allow _RehashPolicy to change that?
  81
  82   // __cache_hash_code: bool.  true if we store the value of the hash
  83   // function along with the value.  This is a time-space tradeoff.
  84   // Storing it may improve lookup speed by reducing the number of times
  85   // we need to call the Equal function.
  86
  87   // __constant_iterators: bool.  true if iterator and const_iterator are
  88   // both constant iterator types.  This is true for unordered_set and
  89   // unordered_multiset, false for unordered_map and unordered_multimap.
  90
  91   // __unique_keys: bool.  true if the return value of _Hashtable::count(k)
  92   // is always at most one, false if it may be an arbitrary number.  This
  93   // true for unordered_set and unordered_map, false for unordered_multiset
  94   // and unordered_multimap.
  95
  96   template<typename _Key, typename _Value, typename _Allocator,
  97            typename _ExtractKey, typename _Equal,
  98            typename _H1, typename _H2, typename _Hash,
  99            typename _RehashPolicy,
 100            bool __cache_hash_code,
 101            bool __constant_iterators,
 102            bool __unique_keys>
 103     class _Hashtable
 104     : public __detail::_Rehash_base<_RehashPolicy,
 105                                     _Hashtable<_Key, _Value, _Allocator,
 106                                                _ExtractKey,
 107                                                _Equal, _H1, _H2, _Hash,
 108                                                _RehashPolicy,
 109                                                __cache_hash_code,
 110                                                __constant_iterators,
 111                                                __unique_keys> >,
 112       public __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 113                                        _H1, _H2, _Hash, __cache_hash_code>,
 114       public __detail::_Map_base<_Key, _Value, _ExtractKey, __unique_keys,
 115                                  _Hashtable<_Key, _Value, _Allocator,
 116                                             _ExtractKey,
 117                                             _Equal, _H1, _H2, _Hash,
 118                                             _RehashPolicy,
 119                                             __cache_hash_code,
 120                                             __constant_iterators,
 121                                             __unique_keys> >
 122     {
 123     public:
 124       typedef _Allocator                                  allocator_type;
 125       typedef _Value                                      value_type;
 126       typedef _Key                                        key_type;
 127       typedef _Equal                                      key_equal;
 128       // mapped_type, if present, comes from _Map_base.
 129       // hasher, if present, comes from _Hash_code_base.
 130       typedef typename _Allocator::difference_type        difference_type;
 131       typedef typename _Allocator::size_type              size_type;
 132       typedef typename _Allocator::pointer                pointer;
 133       typedef typename _Allocator::const_pointer          const_pointer;
 134       typedef typename _Allocator::reference              reference;
 135       typedef typename _Allocator::const_reference        const_reference;
 136
 137       typedef __detail::_Node_iterator<value_type, __constant_iterators,
 138                                        __cache_hash_code>
 139                                                           local_iterator;
 140       typedef __detail::_Node_const_iterator<value_type,
 141                                              __constant_iterators,
 142                                              __cache_hash_code>
 143                                                           const_local_iterator;
 144
 145       typedef __detail::_Hashtable_iterator<value_type, __constant_iterators,
 146                                             __cache_hash_code>
 147                                                           iterator;
 148       typedef __detail::_Hashtable_const_iterator<value_type,
 149                                                   __constant_iterators,
 150                                                   __cache_hash_code>
 151                                                           const_iterator;
 152
 153       template<typename _Key2, typename _Value2, typename _Ex2, bool __unique2,
 154                typename _Hashtable2>
 155         friend struct __detail::_Map_base;
 156
 157     private:
 158       typedef __detail::_Hash_node<_Value, __cache_hash_code> _Node;
 159       typedef typename _Allocator::template rebind<_Node>::other
 160                                                         _Node_allocator_type;
 161       typedef typename _Allocator::template rebind<_Node*>::other
 162                                                         _Bucket_allocator_type;
 163
 164       typedef typename _Allocator::template rebind<_Value>::other
 165                                                         _Value_allocator_type;
 166
 167       _Node_allocator_type   _M_node_allocator;
 168       _Node**                _M_buckets;
 169       size_type              _M_bucket_count;
 170       size_type              _M_element_count;
 171       _RehashPolicy          _M_rehash_policy;
 172
 173       _Node*
 174       _M_allocate_node(const value_type& __v);
 175
 176       void
 177       _M_deallocate_node(_Node* __n);
 178
 179       void
 180       _M_deallocate_nodes(_Node**, size_type);
 181
 182       _Node**
 183       _M_allocate_buckets(size_type __n);
 184
 185       void
 186       _M_deallocate_buckets(_Node**, size_type __n);
 187
 188     public:
 189       // Constructor, destructor, assignment, swap
 190       _Hashtable(size_type __bucket_hint,
 191                  const _H1&, const _H2&, const _Hash&,
 192                  const _Equal&, const _ExtractKey&,
 193                  const allocator_type&);
 194
 195       template<typename _InputIterator>
 196         _Hashtable(_InputIterator __first, _InputIterator __last,
 197                    size_type __bucket_hint,
 198                    const _H1&, const _H2&, const _Hash&,
 199                    const _Equal&, const _ExtractKey&,
 200                    const allocator_type&);
 201
 202       _Hashtable(const _Hashtable&);
 203
 204       _Hashtable(_Hashtable&&);
 205
 206       _Hashtable&
 207       operator=(const _Hashtable&);
 208
 209       ~_Hashtable();
 210
 211       void swap(_Hashtable&);
 212
 213       // Basic container operations
 214       iterator
 215       begin()
 216       {
 217         iterator __i(_M_buckets);
 218         if (!__i._M_cur_node)
 219           __i._M_incr_bucket();
 220         return __i;
 221       }
 222
 223       const_iterator
 224       begin() const
 225       {
 226         const_iterator __i(_M_buckets);
 227         if (!__i._M_cur_node)
 228           __i._M_incr_bucket();
 229         return __i;
 230       }
 231
 232       iterator
 233       end()
 234       { return iterator(_M_buckets + _M_bucket_count); }
 235
 236       const_iterator
 237       end() const
 238       { return const_iterator(_M_buckets + _M_bucket_count); }
 239
 240       const_iterator
 241       cbegin() const
 242       {
 243         const_iterator __i(_M_buckets);
 244         if (!__i._M_cur_node)
 245           __i._M_incr_bucket();
 246         return __i;
 247       }
 248
 249       const_iterator
 250       cend() const
 251       { return const_iterator(_M_buckets + _M_bucket_count); }
 252
 253       size_type
 254       size() const
 255       { return _M_element_count; }
 256
 257       bool
 258       empty() const
 259       { return size() == 0; }
 260
 261       allocator_type
 262       get_allocator() const
 263       { return allocator_type(_M_node_allocator); }
 264
 265       _Value_allocator_type
 266       _M_get_Value_allocator() const
 267       { return _Value_allocator_type(_M_node_allocator); }
 268
 269       size_type
 270       max_size() const
 271       { return _M_node_allocator.max_size(); }
 272
 273       // Observers
 274       key_equal
 275       key_eq() const
 276       { return this->_M_eq; }
 277
 278       // hash_function, if present, comes from _Hash_code_base.
 279
 280       // Bucket operations
 281       size_type
 282       bucket_count() const
 283       { return _M_bucket_count; }
 284
 285       size_type
 286       max_bucket_count() const
 287       { return max_size(); }
 288
 289       size_type
 290       bucket_size(size_type __n) const
 291       { return std::distance(begin(__n), end(__n)); }
 292
 293       size_type
 294       bucket(const key_type& __k) const
 295       {
 296         return this->_M_bucket_index(__k, this->_M_hash_code(__k),
 297                                      bucket_count());
 298       }
 299
 300       local_iterator
 301       begin(size_type __n)
 302       { return local_iterator(_M_buckets[__n]); }
 303
 304       local_iterator
 305       end(size_type)
 306       { return local_iterator(0); }
 307
 308       const_local_iterator
 309       begin(size_type __n) const
 310       { return const_local_iterator(_M_buckets[__n]); }
 311
 312       const_local_iterator
 313       end(size_type) const
 314       { return const_local_iterator(0); }
 315
 316       // DR 691.
 317       const_local_iterator
 318       cbegin(size_type __n) const
 319       { return const_local_iterator(_M_buckets[__n]); }
 320
 321       const_local_iterator
 322       cend(size_type) const
 323       { return const_local_iterator(0); }
 324
 325       float
 326       load_factor() const
 327       {
 328         return static_cast<float>(size()) / static_cast<float>(bucket_count());
 329       }
 330
 331       // max_load_factor, if present, comes from _Rehash_base.
 332
 333       // Generalization of max_load_factor.  Extension, not found in TR1.  Only
 334       // useful if _RehashPolicy is something other than the default.
 335       const _RehashPolicy&
 336       __rehash_policy() const
 337       { return _M_rehash_policy; }
 338
 339       void
 340       __rehash_policy(const _RehashPolicy&);
 341
 342       // Lookup.
 343       iterator
 344       find(const key_type& __k);
 345
 346       const_iterator
 347       find(const key_type& __k) const;
 348
 349       size_type
 350       count(const key_type& __k) const;
 351
 352       std::pair<iterator, iterator>
 353       equal_range(const key_type& __k);
 354
 355       std::pair<const_iterator, const_iterator>
 356       equal_range(const key_type& __k) const;
 357
 358     private:                    // Find, insert and erase helper functions
 359       // ??? This dispatching is a workaround for the fact that we don't
 360       // have partial specialization of member templates; it would be
 361       // better to just specialize insert on __unique_keys.  There may be a
 362       // cleaner workaround.
 363       typedef typename std::conditional<__unique_keys,
 364                                         std::pair<iterator, bool>,
 365                                         iterator>::type
 366         _Insert_Return_Type;
 367
 368       typedef typename std::conditional<__unique_keys,
 369                                         std::_Select1st<_Insert_Return_Type>,
 370                                         std::_Identity<_Insert_Return_Type>
 371                                    >::type
 372         _Insert_Conv_Type;
 373
 374       _Node*
 375       _M_find_node(_Node*, const key_type&,
 376                    typename _Hashtable::_Hash_code_type) const;
 377
 378       iterator
 379       _M_insert_bucket(const value_type&, size_type,
 380                        typename _Hashtable::_Hash_code_type);
 381
 382       std::pair<iterator, bool>
 383       _M_insert(const value_type&, std::true_type);
 384
 385       iterator
 386       _M_insert(const value_type&, std::false_type);
 387
 388     public:
 389       // Insert and erase
 390       _Insert_Return_Type
 391       insert(const value_type& __v)
 392       { return _M_insert(__v, std::integral_constant<bool,
 393                          __unique_keys>()); }
 394
 395       iterator
 396       insert(const_iterator, const value_type& __v)
 397       { return iterator(_Insert_Conv_Type()(this->insert(__v))); }
 398
 399       template<typename _InputIterator>
 400         void
 401         insert(_InputIterator __first, _InputIterator __last);
 402
 403       void
 404       insert(initializer_list<value_type> __l)
 405       { this->insert(__l.begin(), __l.end()); }
 406
 407       void
 408       erase(const_iterator);
 409
 410       size_type
 411       erase(const key_type&);
 412
 413       void
 414       erase(const_iterator, const_iterator);
 415
 416       void
 417       clear();
 418
 419       // Set number of buckets to be appropriate for container of n element.
 420       void rehash(size_type __n);
 421
 422     private:
 423       // Unconditionally change size of bucket array to n.
 424       void _M_rehash(size_type __n);
 425     };
 426
 427
 428   // Definitions of class template _Hashtable's out-of-line member functions.
 429   template<typename _Key, typename _Value,
 430            typename _Allocator, typename _ExtractKey, typename _Equal,
 431            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 432            bool __chc, bool __cit, bool __uk>
 433     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 434                         _H1, _H2, _Hash, _RehashPolicy,
 435                         __chc, __cit, __uk>::_Node*
 436     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 437                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 438     _M_allocate_node(const value_type& __v)
 439     {
 440       _Node* __n = _M_node_allocator.allocate(1);
 441       __try
 442         {
 443           _M_node_allocator.construct(__n, __v);
 444           __n->_M_next = 0;
 445           return __n;
 446         }
 447       __catch(...)
 448         {
 449           _M_node_allocator.deallocate(__n, 1);
 450           __throw_exception_again;
 451         }
 452     }
 453
 454   template<typename _Key, typename _Value,
 455            typename _Allocator, typename _ExtractKey, typename _Equal,
 456            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 457            bool __chc, bool __cit, bool __uk>
 458     void
 459     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 460                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 461     _M_deallocate_node(_Node* __n)
 462     {
 463       _M_node_allocator.destroy(__n);
 464       _M_node_allocator.deallocate(__n, 1);
 465     }
 466
 467   template<typename _Key, typename _Value,
 468            typename _Allocator, typename _ExtractKey, typename _Equal,
 469            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 470            bool __chc, bool __cit, bool __uk>
 471     void
 472     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 473                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 474     _M_deallocate_nodes(_Node** __array, size_type __n)
 475     {
 476       for (size_type __i = 0; __i < __n; ++__i)
 477         {
 478           _Node* __p = __array[__i];
 479           while (__p)
 480             {
 481               _Node* __tmp = __p;
 482               __p = __p->_M_next;
 483               _M_deallocate_node(__tmp);
 484             }
 485           __array[__i] = 0;
 486         }
 487     }
 488
 489   template<typename _Key, typename _Value,
 490            typename _Allocator, typename _ExtractKey, typename _Equal,
 491            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 492            bool __chc, bool __cit, bool __uk>
 493     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 494                         _H1, _H2, _Hash, _RehashPolicy,
 495                         __chc, __cit, __uk>::_Node**
 496     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 497                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 498     _M_allocate_buckets(size_type __n)
 499     {
 500       _Bucket_allocator_type __alloc(_M_node_allocator);
 501
 502       // We allocate one extra bucket to hold a sentinel, an arbitrary
 503       // non-null pointer.  Iterator increment relies on this.
 504       _Node** __p = __alloc.allocate(__n + 1);
 505       std::fill(__p, __p + __n, (_Node*) 0);
 506       __p[__n] = reinterpret_cast<_Node*>(0x1000);
 507       return __p;
 508     }
 509
 510   template<typename _Key, typename _Value,
 511            typename _Allocator, typename _ExtractKey, typename _Equal,
 512            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 513            bool __chc, bool __cit, bool __uk>
 514     void
 515     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 516                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 517     _M_deallocate_buckets(_Node** __p, size_type __n)
 518     {
 519       _Bucket_allocator_type __alloc(_M_node_allocator);
 520       __alloc.deallocate(__p, __n + 1);
 521     }
 522
 523   template<typename _Key, typename _Value,
 524            typename _Allocator, typename _ExtractKey, typename _Equal,
 525            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 526            bool __chc, bool __cit, bool __uk>
 527     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 528                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 529     _Hashtable(size_type __bucket_hint,
 530                const _H1& __h1, const _H2& __h2, const _Hash& __h,
 531                const _Equal& __eq, const _ExtractKey& __exk,
 532                const allocator_type& __a)
 533     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(),
 534       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 535                                 _H1, _H2, _Hash, __chc>(__exk, __eq,
 536                                                         __h1, __h2, __h),
 537       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(),
 538       _M_node_allocator(__a),
 539       _M_bucket_count(0),
 540       _M_element_count(0),
 541       _M_rehash_policy()
 542     {
 543       _M_bucket_count = _M_rehash_policy._M_next_bkt(__bucket_hint);
 544       _M_buckets = _M_allocate_buckets(_M_bucket_count);
 545     }
 546
 547   template<typename _Key, typename _Value,
 548            typename _Allocator, typename _ExtractKey, typename _Equal,
 549            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 550            bool __chc, bool __cit, bool __uk>
 551     template<typename _InputIterator>
 552       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 553                  _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 554       _Hashtable(_InputIterator __f, _InputIterator __l,
 555                  size_type __bucket_hint,
 556                  const _H1& __h1, const _H2& __h2, const _Hash& __h,
 557                  const _Equal& __eq, const _ExtractKey& __exk,
 558                  const allocator_type& __a)
 559       : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(),
 560         __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 561                                   _H1, _H2, _Hash, __chc>(__exk, __eq,
 562                                                           __h1, __h2, __h),
 563         __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(),
 564         _M_node_allocator(__a),
 565         _M_bucket_count(0),
 566         _M_element_count(0),
 567         _M_rehash_policy()
 568       {
 569         _M_bucket_count = std::max(_M_rehash_policy._M_next_bkt(__bucket_hint),
 570                                    _M_rehash_policy.
 571                                    _M_bkt_for_elements(__detail::
 572                                                        __distance_fw(__f,
 573                                                                      __l)));
 574         _M_buckets = _M_allocate_buckets(_M_bucket_count);
 575         __try
 576           {
 577             for (; __f != __l; ++__f)
 578               this->insert(*__f);
 579           }
 580         __catch(...)
 581           {
 582             clear();
 583             _M_deallocate_buckets(_M_buckets, _M_bucket_count);
 584             __throw_exception_again;
 585           }
 586       }
 587
 588   template<typename _Key, typename _Value,
 589            typename _Allocator, typename _ExtractKey, typename _Equal,
 590            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 591            bool __chc, bool __cit, bool __uk>
 592     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 593                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 594     _Hashtable(const _Hashtable& __ht)
 595     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(__ht),
 596       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 597                                 _H1, _H2, _Hash, __chc>(__ht),
 598       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
 599       _M_node_allocator(__ht._M_node_allocator),
 600       _M_bucket_count(__ht._M_bucket_count),
 601       _M_element_count(__ht._M_element_count),
 602       _M_rehash_policy(__ht._M_rehash_policy)
 603     {
 604       _M_buckets = _M_allocate_buckets(_M_bucket_count);
 605       __try
 606         {
 607           for (size_type __i = 0; __i < __ht._M_bucket_count; ++__i)
 608             {
 609               _Node* __n = __ht._M_buckets[__i];
 610               _Node** __tail = _M_buckets + __i;
 611               while (__n)
 612                 {
 613                   *__tail = _M_allocate_node(__n->_M_v);
 614                   this->_M_copy_code(*__tail, __n);
 615                   __tail = &((*__tail)->_M_next);
 616                   __n = __n->_M_next;
 617                 }
 618             }
 619         }
 620       __catch(...)
 621         {
 622           clear();
 623           _M_deallocate_buckets(_M_buckets, _M_bucket_count);
 624           __throw_exception_again;
 625         }
 626     }
 627
 628   template<typename _Key, typename _Value,
 629            typename _Allocator, typename _ExtractKey, typename _Equal,
 630            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 631            bool __chc, bool __cit, bool __uk>
 632     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 633                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 634     _Hashtable(_Hashtable&& __ht)
 635     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(__ht),
 636       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 637                                 _H1, _H2, _Hash, __chc>(__ht),
 638       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
 639       _M_node_allocator(__ht._M_node_allocator),
 640       _M_bucket_count(__ht._M_bucket_count),
 641       _M_element_count(__ht._M_element_count),
 642       _M_rehash_policy(__ht._M_rehash_policy),
 643       _M_buckets(__ht._M_buckets)
 644     {
 645       size_type __n_bkt = __ht._M_rehash_policy._M_next_bkt(0);
 646       __ht._M_buckets = __ht._M_allocate_buckets(__n_bkt);
 647       __ht._M_bucket_count = __n_bkt;
 648       __ht._M_element_count = 0;
 649       __ht._M_rehash_policy = _RehashPolicy();
 650     }
 651
 652   template<typename _Key, typename _Value,
 653            typename _Allocator, typename _ExtractKey, typename _Equal,
 654            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 655            bool __chc, bool __cit, bool __uk>
 656     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 657                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>&
 658     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 659                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 660     operator=(const _Hashtable& __ht)
 661     {
 662       _Hashtable __tmp(__ht);
 663       this->swap(__tmp);
 664       return *this;
 665     }
 666
 667   template<typename _Key, typename _Value,
 668            typename _Allocator, typename _ExtractKey, typename _Equal,
 669            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 670            bool __chc, bool __cit, bool __uk>
 671     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 672                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 673     ~_Hashtable()
 674     {
 675       clear();
 676       _M_deallocate_buckets(_M_buckets, _M_bucket_count);
 677     }
 678
 679   template<typename _Key, typename _Value,
 680            typename _Allocator, typename _ExtractKey, typename _Equal,
 681            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 682            bool __chc, bool __cit, bool __uk>
 683     void
 684     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 685                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 686     swap(_Hashtable& __x)
 687     {
 688       // The only base class with member variables is hash_code_base.  We
 689       // define _Hash_code_base::_M_swap because different specializations
 690       // have different members.
 691       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 692         _H1, _H2, _Hash, __chc>::_M_swap(__x);
 693
 694       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 695       // 431. Swapping containers with unequal allocators.
 696       std::__alloc_swap<_Node_allocator_type>::_S_do_it(_M_node_allocator,
 697                                                         __x._M_node_allocator);
 698
 699       std::swap(_M_rehash_policy, __x._M_rehash_policy);
 700       std::swap(_M_buckets, __x._M_buckets);
 701       std::swap(_M_bucket_count, __x._M_bucket_count);
 702       std::swap(_M_element_count, __x._M_element_count);
 703     }
 704
 705   template<typename _Key, typename _Value,
 706            typename _Allocator, typename _ExtractKey, typename _Equal,
 707            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 708            bool __chc, bool __cit, bool __uk>
 709     void
 710     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 711                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 712     __rehash_policy(const _RehashPolicy& __pol)
 713     {
 714       _M_rehash_policy = __pol;
 715       size_type __n_bkt = __pol._M_bkt_for_elements(_M_element_count);
 716       if (__n_bkt > _M_bucket_count)
 717         _M_rehash(__n_bkt);
 718     }
 719
 720   template<typename _Key, typename _Value,
 721            typename _Allocator, typename _ExtractKey, typename _Equal,
 722            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 723            bool __chc, bool __cit, bool __uk>
 724     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 725                         _H1, _H2, _Hash, _RehashPolicy,
 726                         __chc, __cit, __uk>::iterator
 727     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 728                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 729     find(const key_type& __k)
 730     {
 731       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 732       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 733       _Node* __p = _M_find_node(_M_buckets[__n], __k, __code);
 734       return __p ? iterator(__p, _M_buckets + __n) : this->end();
 735     }
 736
 737   template<typename _Key, typename _Value,
 738            typename _Allocator, typename _ExtractKey, typename _Equal,
 739            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 740            bool __chc, bool __cit, bool __uk>
 741     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 742                         _H1, _H2, _Hash, _RehashPolicy,
 743                         __chc, __cit, __uk>::const_iterator
 744     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 745                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 746     find(const key_type& __k) const
 747     {
 748       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 749       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 750       _Node* __p = _M_find_node(_M_buckets[__n], __k, __code);
 751       return __p ? const_iterator(__p, _M_buckets + __n) : this->end();
 752     }
 753
 754   template<typename _Key, typename _Value,
 755            typename _Allocator, typename _ExtractKey, typename _Equal,
 756            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 757            bool __chc, bool __cit, bool __uk>
 758     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 759                         _H1, _H2, _Hash, _RehashPolicy,
 760                         __chc, __cit, __uk>::size_type
 761     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 762                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 763     count(const key_type& __k) const
 764     {
 765       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 766       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 767       std::size_t __result = 0;
 768       for (_Node* __p = _M_buckets[__n]; __p; __p = __p->_M_next)
 769         if (this->_M_compare(__k, __code, __p))
 770           ++__result;
 771       return __result;
 772     }
 773
 774   template<typename _Key, typename _Value,
 775            typename _Allocator, typename _ExtractKey, typename _Equal,
 776            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 777            bool __chc, bool __cit, bool __uk>
 778     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
 779                                   _ExtractKey, _Equal, _H1,
 780                                   _H2, _Hash, _RehashPolicy,
 781                                   __chc, __cit, __uk>::iterator,
 782               typename _Hashtable<_Key, _Value, _Allocator,
 783                                   _ExtractKey, _Equal, _H1,
 784                                   _H2, _Hash, _RehashPolicy,
 785                                   __chc, __cit, __uk>::iterator>
 786     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 787                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 788     equal_range(const key_type& __k)
 789     {
 790       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 791       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 792       _Node** __head = _M_buckets + __n;
 793       _Node* __p = _M_find_node(*__head, __k, __code);
 794
 795       if (__p)
 796         {
 797           _Node* __p1 = __p->_M_next;
 798           for (; __p1; __p1 = __p1->_M_next)
 799             if (!this->_M_compare(__k, __code, __p1))
 800               break;
 801
 802           iterator __first(__p, __head);
 803           iterator __last(__p1, __head);
 804           if (!__p1)
 805             __last._M_incr_bucket();
 806           return std::make_pair(__first, __last);
 807         }
 808       else
 809         return std::make_pair(this->end(), this->end());
 810     }
 811
 812   template<typename _Key, typename _Value,
 813            typename _Allocator, typename _ExtractKey, typename _Equal,
 814            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 815            bool __chc, bool __cit, bool __uk>
 816     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
 817                                   _ExtractKey, _Equal, _H1,
 818                                   _H2, _Hash, _RehashPolicy,
 819                                   __chc, __cit, __uk>::const_iterator,
 820               typename _Hashtable<_Key, _Value, _Allocator,
 821                                   _ExtractKey, _Equal, _H1,
 822                                   _H2, _Hash, _RehashPolicy,
 823                                   __chc, __cit, __uk>::const_iterator>
 824     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 825                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 826     equal_range(const key_type& __k) const
 827     {
 828       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 829       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 830       _Node** __head = _M_buckets + __n;
 831       _Node* __p = _M_find_node(*__head, __k, __code);
 832
 833       if (__p)
 834         {
 835           _Node* __p1 = __p->_M_next;
 836           for (; __p1; __p1 = __p1->_M_next)
 837             if (!this->_M_compare(__k, __code, __p1))
 838               break;
 839
 840           const_iterator __first(__p, __head);
 841           const_iterator __last(__p1, __head);
 842           if (!__p1)
 843             __last._M_incr_bucket();
 844           return std::make_pair(__first, __last);
 845         }
 846       else
 847         return std::make_pair(this->end(), this->end());
 848     }
 849
 850   // Find the node whose key compares equal to k, beginning the search
 851   // at p (usually the head of a bucket).  Return nil if no node is found.
 852   template<typename _Key, typename _Value,
 853            typename _Allocator, typename _ExtractKey, typename _Equal,
 854            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 855            bool __chc, bool __cit, bool __uk>
 856     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
 857                         _Equal, _H1, _H2, _Hash, _RehashPolicy,
 858                         __chc, __cit, __uk>::_Node*
 859     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 860                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 861     _M_find_node(_Node* __p, const key_type& __k,
 862                 typename _Hashtable::_Hash_code_type __code) const
 863     {
 864       for (; __p; __p = __p->_M_next)
 865         if (this->_M_compare(__k, __code, __p))
 866           return __p;
 867       return false;
 868     }
 869
 870   // Insert v in bucket n (assumes no element with its key already present).
 871   template<typename _Key, typename _Value,
 872            typename _Allocator, typename _ExtractKey, typename _Equal,
 873            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 874            bool __chc, bool __cit, bool __uk>
 875     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 876                         _H1, _H2, _Hash, _RehashPolicy,
 877                         __chc, __cit, __uk>::iterator
 878     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 879                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 880     _M_insert_bucket(const value_type& __v, size_type __n,
 881                      typename _Hashtable::_Hash_code_type __code)
 882     {
 883       std::pair<bool, std::size_t> __do_rehash
 884         = _M_rehash_policy._M_need_rehash(_M_bucket_count,
 885                                           _M_element_count, 1);
 886
 887       // Allocate the new node before doing the rehash so that we don't
 888       // do a rehash if the allocation throws.
 889       _Node* __new_node = _M_allocate_node(__v);
 890
 891       __try
 892         {
 893           if (__do_rehash.first)
 894             {
 895               const key_type& __k = this->_M_extract(__v);
 896               __n = this->_M_bucket_index(__k, __code, __do_rehash.second);
 897               _M_rehash(__do_rehash.second);
 898             }
 899
 900           __new_node->_M_next = _M_buckets[__n];
 901           this->_M_store_code(__new_node, __code);
 902           _M_buckets[__n] = __new_node;
 903           ++_M_element_count;
 904           return iterator(__new_node, _M_buckets + __n);
 905         }
 906       __catch(...)
 907         {
 908           _M_deallocate_node(__new_node);
 909           __throw_exception_again;
 910         }
 911     }
 912
 913   // Insert v if no element with its key is already present.
 914   template<typename _Key, typename _Value,
 915            typename _Allocator, typename _ExtractKey, typename _Equal,
 916            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 917            bool __chc, bool __cit, bool __uk>
 918     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
 919                                   _ExtractKey, _Equal, _H1,
 920                                   _H2, _Hash, _RehashPolicy,
 921                                   __chc, __cit, __uk>::iterator, bool>
 922     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 923                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 924     _M_insert(const value_type& __v, std::true_type)
 925     {
 926       const key_type& __k = this->_M_extract(__v);
 927       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 928       size_type __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 929
 930       if (_Node* __p = _M_find_node(_M_buckets[__n], __k, __code))
 931         return std::make_pair(iterator(__p, _M_buckets + __n), false);
 932       return std::make_pair(_M_insert_bucket(__v, __n, __code), true);
 933     }
 934
 935   // Insert v unconditionally.
 936   template<typename _Key, typename _Value,
 937            typename _Allocator, typename _ExtractKey, typename _Equal,
 938            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 939            bool __chc, bool __cit, bool __uk>
 940     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 941                         _H1, _H2, _Hash, _RehashPolicy,
 942                         __chc, __cit, __uk>::iterator
 943     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 944                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 945     _M_insert(const value_type& __v, std::false_type)
 946     {
 947       std::pair<bool, std::size_t> __do_rehash
 948         = _M_rehash_policy._M_need_rehash(_M_bucket_count,
 949                                           _M_element_count, 1);
 950       if (__do_rehash.first)
 951         _M_rehash(__do_rehash.second);
 952
 953       const key_type& __k = this->_M_extract(__v);
 954       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 955       size_type __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 956
 957       // First find the node, avoid leaking new_node if compare throws.
 958       _Node* __prev = _M_find_node(_M_buckets[__n], __k, __code);
 959       _Node* __new_node = _M_allocate_node(__v);
 960
 961       if (__prev)
 962         {
 963           __new_node->_M_next = __prev->_M_next;
 964           __prev->_M_next = __new_node;
 965         }
 966       else
 967         {
 968           __new_node->_M_next = _M_buckets[__n];
 969           _M_buckets[__n] = __new_node;
 970         }
 971       this->_M_store_code(__new_node, __code);
 972
 973       ++_M_element_count;
 974       return iterator(__new_node, _M_buckets + __n);
 975     }
 976
 977   template<typename _Key, typename _Value,
 978            typename _Allocator, typename _ExtractKey, typename _Equal,
 979            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 980            bool __chc, bool __cit, bool __uk>
 981     template<typename _InputIterator>
 982       void
 983       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 984                  _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 985       insert(_InputIterator __first, _InputIterator __last)
 986       {
 987         size_type __n_elt = __detail::__distance_fw(__first, __last);
 988         std::pair<bool, std::size_t> __do_rehash
 989           = _M_rehash_policy._M_need_rehash(_M_bucket_count,
 990                                             _M_element_count, __n_elt);
 991         if (__do_rehash.first)
 992           _M_rehash(__do_rehash.second);
 993
 994         for (; __first != __last; ++__first)
 995           this->insert(*__first);
 996       }
 997
 998   template<typename _Key, typename _Value,
 999            typename _Allocator, typename _ExtractKey, typename _Equal,
1000            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1001            bool __chc, bool __cit, bool __uk>
1002     void
1003     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1004                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1005     erase(const_iterator __it)
1006     {
1007       _Node* __p = __it._M_cur_node;
1008       _Node** __b = __it._M_cur_bucket;
1009
1010       _Node* __cur = *__b;
1011       if (__cur == __p)
1012         *__b = __cur->_M_next;
1013       else
1014         {
1015           _Node* __next = __cur->_M_next;
1016           while (__next != __p)
1017             {
1018               __cur = __next;
1019               __next = __cur->_M_next;
1020             }
1021           __cur->_M_next = __next->_M_next;
1022         }
1023
1024       _M_deallocate_node(__p);
1025       --_M_element_count;
1026     }
1027
1028   template<typename _Key, typename _Value,
1029            typename _Allocator, typename _ExtractKey, typename _Equal,
1030            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1031            bool __chc, bool __cit, bool __uk>
1032     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1033                         _H1, _H2, _Hash, _RehashPolicy,
1034                         __chc, __cit, __uk>::size_type
1035     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1036                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1037     erase(const key_type& __k)
1038     {
1039       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
1040       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
1041       size_type __result = 0;
1042
1043       _Node** __slot = _M_buckets + __n;
1044       while (*__slot && !this->_M_compare(__k, __code, *__slot))
1045         __slot = &((*__slot)->_M_next);
1046
1047       _Node** __saved_slot = 0;
1048       while (*__slot && this->_M_compare(__k, __code, *__slot))
1049         {
1050           // _GLIBCXX_RESOLVE_LIB_DEFECTS
1051           // 526. Is it undefined if a function in the standard changes
1052           // in parameters?
1053           if (&this->_M_extract((*__slot)->_M_v) != &__k)
1054             {
1055               _Node* __p = *__slot;
1056               *__slot = __p->_M_next;
1057               _M_deallocate_node(__p);
1058               --_M_element_count;
1059               ++__result;
1060             }
1061           else
1062             {
1063               __saved_slot = __slot;
1064               __slot = &((*__slot)->_M_next);
1065             }
1066         }
1067
1068       if (__saved_slot)
1069         {
1070           _Node* __p = *__saved_slot;
1071           *__saved_slot = __p->_M_next;
1072           _M_deallocate_node(__p);
1073           --_M_element_count;
1074           ++__result;
1075         }
1076
1077       return __result;
1078     }
1079
1080   // ??? This could be optimized by taking advantage of the bucket
1081   // structure, but it's not clear that it's worth doing.  It probably
1082   // wouldn't even be an optimization unless the load factor is large.
1083   template<typename _Key, typename _Value,
1084            typename _Allocator, typename _ExtractKey, typename _Equal,
1085            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1086            bool __chc, bool __cit, bool __uk>
1087     void
1088     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1089                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1090     erase(const_iterator __first, const_iterator __last)
1091     {
1092       if (__first == begin() && __last == end())
1093         clear();
1094       else
1095         while (__first != __last)
1096           erase(__first++);
1097      }
1098
1099   template<typename _Key, typename _Value,
1100            typename _Allocator, typename _ExtractKey, typename _Equal,
1101            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1102            bool __chc, bool __cit, bool __uk>
1103     void
1104     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1105                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1106     clear()
1107     {
1108       _M_deallocate_nodes(_M_buckets, _M_bucket_count);
1109       _M_element_count = 0;
1110     }
1111
1112   template<typename _Key, typename _Value,
1113            typename _Allocator, typename _ExtractKey, typename _Equal,
1114            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1115            bool __chc, bool __cit, bool __uk>
1116     void
1117     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1118                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1119     rehash(size_type __n)
1120     {
1121       _M_rehash(std::max(_M_rehash_policy._M_next_bkt(__n),
1122                          _M_rehash_policy._M_bkt_for_elements(_M_element_count
1123                                                               + 1)));
1124     }
1125
1126   template<typename _Key, typename _Value,
1127            typename _Allocator, typename _ExtractKey, typename _Equal,
1128            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1129            bool __chc, bool __cit, bool __uk>
1130     void
1131     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1132                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1133     _M_rehash(size_type __n)
1134     {
1135       _Node** __new_array = _M_allocate_buckets(__n);
1136       __try
1137         {
1138           for (size_type __i = 0; __i < _M_bucket_count; ++__i)
1139             while (_Node* __p = _M_buckets[__i])
1140               {
1141                 std::size_t __new_index = this->_M_bucket_index(__p, __n);
1142                 _M_buckets[__i] = __p->_M_next;
1143                 __p->_M_next = __new_array[__new_index];
1144                 __new_array[__new_index] = __p;
1145               }
1146           _M_deallocate_buckets(_M_buckets, _M_bucket_count);
1147           _M_bucket_count = __n;
1148           _M_buckets = __new_array;
1149         }
1150       __catch(...)
1151         {
1152           // A failure here means that a hash function threw an exception.
1153           // We can't restore the previous state without calling the hash
1154           // function again, so the only sensible recovery is to delete
1155           // everything.
1156           _M_deallocate_nodes(__new_array, __n);
1157           _M_deallocate_buckets(__new_array, __n);
1158           _M_deallocate_nodes(_M_buckets, _M_bucket_count);
1159           _M_element_count = 0;
1160           __throw_exception_again;
1161         }
1162     }
1163 }
1164
1165 #endif // _HASHTABLE_H