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       void
 389       _M_erase_node(_Node*, _Node**);
 390
 391     public:
 392       // Insert and erase
 393       _Insert_Return_Type
 394       insert(const value_type& __v)
 395       { return _M_insert(__v, std::integral_constant<bool,
 396                          __unique_keys>()); }
 397
 398       iterator
 399       insert(const_iterator, const value_type& __v)
 400       { return iterator(_Insert_Conv_Type()(this->insert(__v))); }
 401
 402       template<typename _InputIterator>
 403         void
 404         insert(_InputIterator __first, _InputIterator __last);
 405
 406       void
 407       insert(initializer_list<value_type> __l)
 408       { this->insert(__l.begin(), __l.end()); }
 409
 410       iterator
 411       erase(const_iterator);
 412
 413       size_type
 414       erase(const key_type&);
 415
 416       iterator
 417       erase(const_iterator, const_iterator);
 418
 419       void
 420       clear();
 421
 422       // Set number of buckets to be appropriate for container of n element.
 423       void rehash(size_type __n);
 424
 425     private:
 426       // Unconditionally change size of bucket array to n.
 427       void _M_rehash(size_type __n);
 428     };
 429
 430
 431   // Definitions of class template _Hashtable's out-of-line member functions.
 432   template<typename _Key, typename _Value,
 433            typename _Allocator, typename _ExtractKey, typename _Equal,
 434            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 435            bool __chc, bool __cit, bool __uk>
 436     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 437                         _H1, _H2, _Hash, _RehashPolicy,
 438                         __chc, __cit, __uk>::_Node*
 439     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 440                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 441     _M_allocate_node(const value_type& __v)
 442     {
 443       _Node* __n = _M_node_allocator.allocate(1);
 444       __try
 445         {
 446           _M_node_allocator.construct(__n, __v);
 447           __n->_M_next = 0;
 448           return __n;
 449         }
 450       __catch(...)
 451         {
 452           _M_node_allocator.deallocate(__n, 1);
 453           __throw_exception_again;
 454         }
 455     }
 456
 457   template<typename _Key, typename _Value,
 458            typename _Allocator, typename _ExtractKey, typename _Equal,
 459            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 460            bool __chc, bool __cit, bool __uk>
 461     void
 462     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 463                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 464     _M_deallocate_node(_Node* __n)
 465     {
 466       _M_node_allocator.destroy(__n);
 467       _M_node_allocator.deallocate(__n, 1);
 468     }
 469
 470   template<typename _Key, typename _Value,
 471            typename _Allocator, typename _ExtractKey, typename _Equal,
 472            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 473            bool __chc, bool __cit, bool __uk>
 474     void
 475     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 476                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 477     _M_deallocate_nodes(_Node** __array, size_type __n)
 478     {
 479       for (size_type __i = 0; __i < __n; ++__i)
 480         {
 481           _Node* __p = __array[__i];
 482           while (__p)
 483             {
 484               _Node* __tmp = __p;
 485               __p = __p->_M_next;
 486               _M_deallocate_node(__tmp);
 487             }
 488           __array[__i] = 0;
 489         }
 490     }
 491
 492   template<typename _Key, typename _Value,
 493            typename _Allocator, typename _ExtractKey, typename _Equal,
 494            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 495            bool __chc, bool __cit, bool __uk>
 496     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 497                         _H1, _H2, _Hash, _RehashPolicy,
 498                         __chc, __cit, __uk>::_Node**
 499     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 500                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 501     _M_allocate_buckets(size_type __n)
 502     {
 503       _Bucket_allocator_type __alloc(_M_node_allocator);
 504
 505       // We allocate one extra bucket to hold a sentinel, an arbitrary
 506       // non-null pointer.  Iterator increment relies on this.
 507       _Node** __p = __alloc.allocate(__n + 1);
 508       std::fill(__p, __p + __n, (_Node*) 0);
 509       __p[__n] = reinterpret_cast<_Node*>(0x1000);
 510       return __p;
 511     }
 512
 513   template<typename _Key, typename _Value,
 514            typename _Allocator, typename _ExtractKey, typename _Equal,
 515            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 516            bool __chc, bool __cit, bool __uk>
 517     void
 518     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 519                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 520     _M_deallocate_buckets(_Node** __p, size_type __n)
 521     {
 522       _Bucket_allocator_type __alloc(_M_node_allocator);
 523       __alloc.deallocate(__p, __n + 1);
 524     }
 525
 526   template<typename _Key, typename _Value,
 527            typename _Allocator, typename _ExtractKey, typename _Equal,
 528            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 529            bool __chc, bool __cit, bool __uk>
 530     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 531                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 532     _Hashtable(size_type __bucket_hint,
 533                const _H1& __h1, const _H2& __h2, const _Hash& __h,
 534                const _Equal& __eq, const _ExtractKey& __exk,
 535                const allocator_type& __a)
 536     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(),
 537       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 538                                 _H1, _H2, _Hash, __chc>(__exk, __eq,
 539                                                         __h1, __h2, __h),
 540       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(),
 541       _M_node_allocator(__a),
 542       _M_bucket_count(0),
 543       _M_element_count(0),
 544       _M_rehash_policy()
 545     {
 546       _M_bucket_count = _M_rehash_policy._M_next_bkt(__bucket_hint);
 547       _M_buckets = _M_allocate_buckets(_M_bucket_count);
 548     }
 549
 550   template<typename _Key, typename _Value,
 551            typename _Allocator, typename _ExtractKey, typename _Equal,
 552            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 553            bool __chc, bool __cit, bool __uk>
 554     template<typename _InputIterator>
 555       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 556                  _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 557       _Hashtable(_InputIterator __f, _InputIterator __l,
 558                  size_type __bucket_hint,
 559                  const _H1& __h1, const _H2& __h2, const _Hash& __h,
 560                  const _Equal& __eq, const _ExtractKey& __exk,
 561                  const allocator_type& __a)
 562       : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(),
 563         __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 564                                   _H1, _H2, _Hash, __chc>(__exk, __eq,
 565                                                           __h1, __h2, __h),
 566         __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(),
 567         _M_node_allocator(__a),
 568         _M_bucket_count(0),
 569         _M_element_count(0),
 570         _M_rehash_policy()
 571       {
 572         _M_bucket_count = std::max(_M_rehash_policy._M_next_bkt(__bucket_hint),
 573                                    _M_rehash_policy.
 574                                    _M_bkt_for_elements(__detail::
 575                                                        __distance_fw(__f,
 576                                                                      __l)));
 577         _M_buckets = _M_allocate_buckets(_M_bucket_count);
 578         __try
 579           {
 580             for (; __f != __l; ++__f)
 581               this->insert(*__f);
 582           }
 583         __catch(...)
 584           {
 585             clear();
 586             _M_deallocate_buckets(_M_buckets, _M_bucket_count);
 587             __throw_exception_again;
 588           }
 589       }
 590
 591   template<typename _Key, typename _Value,
 592            typename _Allocator, typename _ExtractKey, typename _Equal,
 593            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 594            bool __chc, bool __cit, bool __uk>
 595     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 596                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 597     _Hashtable(const _Hashtable& __ht)
 598     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(__ht),
 599       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 600                                 _H1, _H2, _Hash, __chc>(__ht),
 601       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
 602       _M_node_allocator(__ht._M_node_allocator),
 603       _M_bucket_count(__ht._M_bucket_count),
 604       _M_element_count(__ht._M_element_count),
 605       _M_rehash_policy(__ht._M_rehash_policy)
 606     {
 607       _M_buckets = _M_allocate_buckets(_M_bucket_count);
 608       __try
 609         {
 610           for (size_type __i = 0; __i < __ht._M_bucket_count; ++__i)
 611             {
 612               _Node* __n = __ht._M_buckets[__i];
 613               _Node** __tail = _M_buckets + __i;
 614               while (__n)
 615                 {
 616                   *__tail = _M_allocate_node(__n->_M_v);
 617                   this->_M_copy_code(*__tail, __n);
 618                   __tail = &((*__tail)->_M_next);
 619                   __n = __n->_M_next;
 620                 }
 621             }
 622         }
 623       __catch(...)
 624         {
 625           clear();
 626           _M_deallocate_buckets(_M_buckets, _M_bucket_count);
 627           __throw_exception_again;
 628         }
 629     }
 630
 631   template<typename _Key, typename _Value,
 632            typename _Allocator, typename _ExtractKey, typename _Equal,
 633            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 634            bool __chc, bool __cit, bool __uk>
 635     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 636                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 637     _Hashtable(_Hashtable&& __ht)
 638     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(__ht),
 639       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 640                                 _H1, _H2, _Hash, __chc>(__ht),
 641       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
 642       _M_node_allocator(__ht._M_node_allocator),
 643       _M_bucket_count(__ht._M_bucket_count),
 644       _M_element_count(__ht._M_element_count),
 645       _M_rehash_policy(__ht._M_rehash_policy),
 646       _M_buckets(__ht._M_buckets)
 647     {
 648       size_type __n_bkt = __ht._M_rehash_policy._M_next_bkt(0);
 649       __ht._M_buckets = __ht._M_allocate_buckets(__n_bkt);
 650       __ht._M_bucket_count = __n_bkt;
 651       __ht._M_element_count = 0;
 652       __ht._M_rehash_policy = _RehashPolicy();
 653     }
 654
 655   template<typename _Key, typename _Value,
 656            typename _Allocator, typename _ExtractKey, typename _Equal,
 657            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 658            bool __chc, bool __cit, bool __uk>
 659     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 660                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>&
 661     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 662                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 663     operator=(const _Hashtable& __ht)
 664     {
 665       _Hashtable __tmp(__ht);
 666       this->swap(__tmp);
 667       return *this;
 668     }
 669
 670   template<typename _Key, typename _Value,
 671            typename _Allocator, typename _ExtractKey, typename _Equal,
 672            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 673            bool __chc, bool __cit, bool __uk>
 674     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 675                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 676     ~_Hashtable()
 677     {
 678       clear();
 679       _M_deallocate_buckets(_M_buckets, _M_bucket_count);
 680     }
 681
 682   template<typename _Key, typename _Value,
 683            typename _Allocator, typename _ExtractKey, typename _Equal,
 684            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 685            bool __chc, bool __cit, bool __uk>
 686     void
 687     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 688                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 689     swap(_Hashtable& __x)
 690     {
 691       // The only base class with member variables is hash_code_base.  We
 692       // define _Hash_code_base::_M_swap because different specializations
 693       // have different members.
 694       __detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal,
 695         _H1, _H2, _Hash, __chc>::_M_swap(__x);
 696
 697       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 698       // 431. Swapping containers with unequal allocators.
 699       std::__alloc_swap<_Node_allocator_type>::_S_do_it(_M_node_allocator,
 700                                                         __x._M_node_allocator);
 701
 702       std::swap(_M_rehash_policy, __x._M_rehash_policy);
 703       std::swap(_M_buckets, __x._M_buckets);
 704       std::swap(_M_bucket_count, __x._M_bucket_count);
 705       std::swap(_M_element_count, __x._M_element_count);
 706     }
 707
 708   template<typename _Key, typename _Value,
 709            typename _Allocator, typename _ExtractKey, typename _Equal,
 710            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 711            bool __chc, bool __cit, bool __uk>
 712     void
 713     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 714                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 715     __rehash_policy(const _RehashPolicy& __pol)
 716     {
 717       _M_rehash_policy = __pol;
 718       size_type __n_bkt = __pol._M_bkt_for_elements(_M_element_count);
 719       if (__n_bkt > _M_bucket_count)
 720         _M_rehash(__n_bkt);
 721     }
 722
 723   template<typename _Key, typename _Value,
 724            typename _Allocator, typename _ExtractKey, typename _Equal,
 725            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 726            bool __chc, bool __cit, bool __uk>
 727     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 728                         _H1, _H2, _Hash, _RehashPolicy,
 729                         __chc, __cit, __uk>::iterator
 730     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 731                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 732     find(const key_type& __k)
 733     {
 734       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 735       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 736       _Node* __p = _M_find_node(_M_buckets[__n], __k, __code);
 737       return __p ? iterator(__p, _M_buckets + __n) : this->end();
 738     }
 739
 740   template<typename _Key, typename _Value,
 741            typename _Allocator, typename _ExtractKey, typename _Equal,
 742            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 743            bool __chc, bool __cit, bool __uk>
 744     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 745                         _H1, _H2, _Hash, _RehashPolicy,
 746                         __chc, __cit, __uk>::const_iterator
 747     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 748                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 749     find(const key_type& __k) const
 750     {
 751       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 752       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 753       _Node* __p = _M_find_node(_M_buckets[__n], __k, __code);
 754       return __p ? const_iterator(__p, _M_buckets + __n) : this->end();
 755     }
 756
 757   template<typename _Key, typename _Value,
 758            typename _Allocator, typename _ExtractKey, typename _Equal,
 759            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 760            bool __chc, bool __cit, bool __uk>
 761     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 762                         _H1, _H2, _Hash, _RehashPolicy,
 763                         __chc, __cit, __uk>::size_type
 764     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 765                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 766     count(const key_type& __k) const
 767     {
 768       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 769       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 770       std::size_t __result = 0;
 771       for (_Node* __p = _M_buckets[__n]; __p; __p = __p->_M_next)
 772         if (this->_M_compare(__k, __code, __p))
 773           ++__result;
 774       return __result;
 775     }
 776
 777   template<typename _Key, typename _Value,
 778            typename _Allocator, typename _ExtractKey, typename _Equal,
 779            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 780            bool __chc, bool __cit, bool __uk>
 781     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
 782                                   _ExtractKey, _Equal, _H1,
 783                                   _H2, _Hash, _RehashPolicy,
 784                                   __chc, __cit, __uk>::iterator,
 785               typename _Hashtable<_Key, _Value, _Allocator,
 786                                   _ExtractKey, _Equal, _H1,
 787                                   _H2, _Hash, _RehashPolicy,
 788                                   __chc, __cit, __uk>::iterator>
 789     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 790                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 791     equal_range(const key_type& __k)
 792     {
 793       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 794       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 795       _Node** __head = _M_buckets + __n;
 796       _Node* __p = _M_find_node(*__head, __k, __code);
 797
 798       if (__p)
 799         {
 800           _Node* __p1 = __p->_M_next;
 801           for (; __p1; __p1 = __p1->_M_next)
 802             if (!this->_M_compare(__k, __code, __p1))
 803               break;
 804
 805           iterator __first(__p, __head);
 806           iterator __last(__p1, __head);
 807           if (!__p1)
 808             __last._M_incr_bucket();
 809           return std::make_pair(__first, __last);
 810         }
 811       else
 812         return std::make_pair(this->end(), this->end());
 813     }
 814
 815   template<typename _Key, typename _Value,
 816            typename _Allocator, typename _ExtractKey, typename _Equal,
 817            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 818            bool __chc, bool __cit, bool __uk>
 819     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
 820                                   _ExtractKey, _Equal, _H1,
 821                                   _H2, _Hash, _RehashPolicy,
 822                                   __chc, __cit, __uk>::const_iterator,
 823               typename _Hashtable<_Key, _Value, _Allocator,
 824                                   _ExtractKey, _Equal, _H1,
 825                                   _H2, _Hash, _RehashPolicy,
 826                                   __chc, __cit, __uk>::const_iterator>
 827     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 828                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 829     equal_range(const key_type& __k) const
 830     {
 831       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 832       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 833       _Node** __head = _M_buckets + __n;
 834       _Node* __p = _M_find_node(*__head, __k, __code);
 835
 836       if (__p)
 837         {
 838           _Node* __p1 = __p->_M_next;
 839           for (; __p1; __p1 = __p1->_M_next)
 840             if (!this->_M_compare(__k, __code, __p1))
 841               break;
 842
 843           const_iterator __first(__p, __head);
 844           const_iterator __last(__p1, __head);
 845           if (!__p1)
 846             __last._M_incr_bucket();
 847           return std::make_pair(__first, __last);
 848         }
 849       else
 850         return std::make_pair(this->end(), this->end());
 851     }
 852
 853   // Find the node whose key compares equal to k, beginning the search
 854   // at p (usually the head of a bucket).  Return nil if no node is found.
 855   template<typename _Key, typename _Value,
 856            typename _Allocator, typename _ExtractKey, typename _Equal,
 857            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 858            bool __chc, bool __cit, bool __uk>
 859     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
 860                         _Equal, _H1, _H2, _Hash, _RehashPolicy,
 861                         __chc, __cit, __uk>::_Node*
 862     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 863                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 864     _M_find_node(_Node* __p, const key_type& __k,
 865                 typename _Hashtable::_Hash_code_type __code) const
 866     {
 867       for (; __p; __p = __p->_M_next)
 868         if (this->_M_compare(__k, __code, __p))
 869           return __p;
 870       return false;
 871     }
 872
 873   // Insert v in bucket n (assumes no element with its key already present).
 874   template<typename _Key, typename _Value,
 875            typename _Allocator, typename _ExtractKey, typename _Equal,
 876            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 877            bool __chc, bool __cit, bool __uk>
 878     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 879                         _H1, _H2, _Hash, _RehashPolicy,
 880                         __chc, __cit, __uk>::iterator
 881     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 882                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 883     _M_insert_bucket(const value_type& __v, size_type __n,
 884                      typename _Hashtable::_Hash_code_type __code)
 885     {
 886       std::pair<bool, std::size_t> __do_rehash
 887         = _M_rehash_policy._M_need_rehash(_M_bucket_count,
 888                                           _M_element_count, 1);
 889
 890       // Allocate the new node before doing the rehash so that we don't
 891       // do a rehash if the allocation throws.
 892       _Node* __new_node = _M_allocate_node(__v);
 893
 894       __try
 895         {
 896           if (__do_rehash.first)
 897             {
 898               const key_type& __k = this->_M_extract(__v);
 899               __n = this->_M_bucket_index(__k, __code, __do_rehash.second);
 900               _M_rehash(__do_rehash.second);
 901             }
 902
 903           __new_node->_M_next = _M_buckets[__n];
 904           this->_M_store_code(__new_node, __code);
 905           _M_buckets[__n] = __new_node;
 906           ++_M_element_count;
 907           return iterator(__new_node, _M_buckets + __n);
 908         }
 909       __catch(...)
 910         {
 911           _M_deallocate_node(__new_node);
 912           __throw_exception_again;
 913         }
 914     }
 915
 916   // Insert v if no element with its key is already present.
 917   template<typename _Key, typename _Value,
 918            typename _Allocator, typename _ExtractKey, typename _Equal,
 919            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 920            bool __chc, bool __cit, bool __uk>
 921     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
 922                                   _ExtractKey, _Equal, _H1,
 923                                   _H2, _Hash, _RehashPolicy,
 924                                   __chc, __cit, __uk>::iterator, bool>
 925     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 926                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 927     _M_insert(const value_type& __v, std::true_type)
 928     {
 929       const key_type& __k = this->_M_extract(__v);
 930       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 931       size_type __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 932
 933       if (_Node* __p = _M_find_node(_M_buckets[__n], __k, __code))
 934         return std::make_pair(iterator(__p, _M_buckets + __n), false);
 935       return std::make_pair(_M_insert_bucket(__v, __n, __code), true);
 936     }
 937
 938   // Insert v unconditionally.
 939   template<typename _Key, typename _Value,
 940            typename _Allocator, typename _ExtractKey, typename _Equal,
 941            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 942            bool __chc, bool __cit, bool __uk>
 943     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 944                         _H1, _H2, _Hash, _RehashPolicy,
 945                         __chc, __cit, __uk>::iterator
 946     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 947                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 948     _M_insert(const value_type& __v, std::false_type)
 949     {
 950       std::pair<bool, std::size_t> __do_rehash
 951         = _M_rehash_policy._M_need_rehash(_M_bucket_count,
 952                                           _M_element_count, 1);
 953       if (__do_rehash.first)
 954         _M_rehash(__do_rehash.second);
 955
 956       const key_type& __k = this->_M_extract(__v);
 957       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
 958       size_type __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
 959
 960       // First find the node, avoid leaking new_node if compare throws.
 961       _Node* __prev = _M_find_node(_M_buckets[__n], __k, __code);
 962       _Node* __new_node = _M_allocate_node(__v);
 963
 964       if (__prev)
 965         {
 966           __new_node->_M_next = __prev->_M_next;
 967           __prev->_M_next = __new_node;
 968         }
 969       else
 970         {
 971           __new_node->_M_next = _M_buckets[__n];
 972           _M_buckets[__n] = __new_node;
 973         }
 974       this->_M_store_code(__new_node, __code);
 975
 976       ++_M_element_count;
 977       return iterator(__new_node, _M_buckets + __n);
 978     }
 979
 980   // For erase(iterator) and erase(const_iterator).
 981   template<typename _Key, typename _Value,
 982            typename _Allocator, typename _ExtractKey, typename _Equal,
 983            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 984            bool __chc, bool __cit, bool __uk>
 985     void
 986     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
 987                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
 988     _M_erase_node(_Node* __p, _Node** __b)
 989     {
 990       _Node* __cur = *__b;
 991       if (__cur == __p)
 992         *__b = __cur->_M_next;
 993       else
 994         {
 995           _Node* __next = __cur->_M_next;
 996           while (__next != __p)
 997             {
 998               __cur = __next;
 999               __next = __cur->_M_next;
1000             }
1001           __cur->_M_next = __next->_M_next;
1002         }
1003
1004       _M_deallocate_node(__p);
1005       --_M_element_count;
1006     }
1007
1008   template<typename _Key, typename _Value,
1009            typename _Allocator, typename _ExtractKey, typename _Equal,
1010            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1011            bool __chc, bool __cit, bool __uk>
1012     template<typename _InputIterator>
1013       void
1014       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1015                  _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1016       insert(_InputIterator __first, _InputIterator __last)
1017       {
1018         size_type __n_elt = __detail::__distance_fw(__first, __last);
1019         std::pair<bool, std::size_t> __do_rehash
1020           = _M_rehash_policy._M_need_rehash(_M_bucket_count,
1021                                             _M_element_count, __n_elt);
1022         if (__do_rehash.first)
1023           _M_rehash(__do_rehash.second);
1024
1025         for (; __first != __last; ++__first)
1026           this->insert(*__first);
1027       }
1028
1029   template<typename _Key, typename _Value,
1030            typename _Allocator, typename _ExtractKey, typename _Equal,
1031            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1032            bool __chc, bool __cit, bool __uk>
1033     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1034                         _H1, _H2, _Hash, _RehashPolicy,
1035                         __chc, __cit, __uk>::iterator
1036     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1037                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1038     erase(const_iterator __it)
1039     {
1040       iterator __result(__it._M_cur_node, __it._M_cur_bucket);
1041       ++__result;
1042       _M_erase_node(__it._M_cur_node, __it._M_cur_bucket);
1043       return __result;
1044     }
1045
1046   template<typename _Key, typename _Value,
1047            typename _Allocator, typename _ExtractKey, typename _Equal,
1048            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1049            bool __chc, bool __cit, bool __uk>
1050     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1051                         _H1, _H2, _Hash, _RehashPolicy,
1052                         __chc, __cit, __uk>::size_type
1053     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1054                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1055     erase(const key_type& __k)
1056     {
1057       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
1058       std::size_t __n = this->_M_bucket_index(__k, __code, _M_bucket_count);
1059       size_type __result = 0;
1060
1061       _Node** __slot = _M_buckets + __n;
1062       while (*__slot && !this->_M_compare(__k, __code, *__slot))
1063         __slot = &((*__slot)->_M_next);
1064
1065       _Node** __saved_slot = 0;
1066       while (*__slot && this->_M_compare(__k, __code, *__slot))
1067         {
1068           // _GLIBCXX_RESOLVE_LIB_DEFECTS
1069           // 526. Is it undefined if a function in the standard changes
1070           // in parameters?
1071           if (&this->_M_extract((*__slot)->_M_v) != &__k)
1072             {
1073               _Node* __p = *__slot;
1074               *__slot = __p->_M_next;
1075               _M_deallocate_node(__p);
1076               --_M_element_count;
1077               ++__result;
1078             }
1079           else
1080             {
1081               __saved_slot = __slot;
1082               __slot = &((*__slot)->_M_next);
1083             }
1084         }
1085
1086       if (__saved_slot)
1087         {
1088           _Node* __p = *__saved_slot;
1089           *__saved_slot = __p->_M_next;
1090           _M_deallocate_node(__p);
1091           --_M_element_count;
1092           ++__result;
1093         }
1094
1095       return __result;
1096     }
1097
1098   // ??? This could be optimized by taking advantage of the bucket
1099   // structure, but it's not clear that it's worth doing.  It probably
1100   // wouldn't even be an optimization unless the load factor is large.
1101   template<typename _Key, typename _Value,
1102            typename _Allocator, typename _ExtractKey, typename _Equal,
1103            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1104            bool __chc, bool __cit, bool __uk>
1105     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1106                         _H1, _H2, _Hash, _RehashPolicy,
1107                         __chc, __cit, __uk>::iterator
1108     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1109                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1110     erase(const_iterator __first, const_iterator __last)
1111     {
1112       while (__first != __last)
1113         __first = this->erase(__first);
1114       return iterator(__last._M_cur_node, __last._M_cur_bucket);
1115     }
1116
1117   template<typename _Key, typename _Value,
1118            typename _Allocator, typename _ExtractKey, typename _Equal,
1119            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1120            bool __chc, bool __cit, bool __uk>
1121     void
1122     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1123                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1124     clear()
1125     {
1126       _M_deallocate_nodes(_M_buckets, _M_bucket_count);
1127       _M_element_count = 0;
1128     }
1129
1130   template<typename _Key, typename _Value,
1131            typename _Allocator, typename _ExtractKey, typename _Equal,
1132            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1133            bool __chc, bool __cit, bool __uk>
1134     void
1135     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1136                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1137     rehash(size_type __n)
1138     {
1139       _M_rehash(std::max(_M_rehash_policy._M_next_bkt(__n),
1140                          _M_rehash_policy._M_bkt_for_elements(_M_element_count
1141                                                               + 1)));
1142     }
1143
1144   template<typename _Key, typename _Value,
1145            typename _Allocator, typename _ExtractKey, typename _Equal,
1146            typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1147            bool __chc, bool __cit, bool __uk>
1148     void
1149     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
1150                _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
1151     _M_rehash(size_type __n)
1152     {
1153       _Node** __new_array = _M_allocate_buckets(__n);
1154       __try
1155         {
1156           for (size_type __i = 0; __i < _M_bucket_count; ++__i)
1157             while (_Node* __p = _M_buckets[__i])
1158               {
1159                 std::size_t __new_index = this->_M_bucket_index(__p, __n);
1160                 _M_buckets[__i] = __p->_M_next;
1161                 __p->_M_next = __new_array[__new_index];
1162                 __new_array[__new_index] = __p;
1163               }
1164           _M_deallocate_buckets(_M_buckets, _M_bucket_count);
1165           _M_bucket_count = __n;
1166           _M_buckets = __new_array;
1167         }
1168       __catch(...)
1169         {
1170           // A failure here means that a hash function threw an exception.
1171           // We can't restore the previous state without calling the hash
1172           // function again, so the only sensible recovery is to delete
1173           // everything.
1174           _M_deallocate_nodes(__new_array, __n);
1175           _M_deallocate_buckets(__new_array, __n);
1176           _M_deallocate_nodes(_M_buckets, _M_bucket_count);
1177           _M_element_count = 0;
1178           __throw_exception_again;
1179         }
1180     }
1181 }
1182
1183 #endif // _HASHTABLE_H