Home | History | Annotate | Download | only in include
      1 // -*- C++ -*-
      2 //===----------------------------------------------------------------------===//
      3 //
      4 //                     The LLVM Compiler Infrastructure
      5 //
      6 // This file is dual licensed under the MIT and the University of Illinois Open
      7 // Source Licenses. See LICENSE.TXT for details.
      8 //
      9 //===----------------------------------------------------------------------===//
     10 
     11 #ifndef _LIBCPP__HASH_TABLE
     12 #define _LIBCPP__HASH_TABLE
     13 
     14 #include <__config>
     15 #include <initializer_list>
     16 #include <memory>
     17 #include <iterator>
     18 #include <algorithm>
     19 #include <cmath>
     20 #include <utility>
     21 #include <type_traits>
     22 
     23 #include <__undef_min_max>
     24 
     25 #include <__debug>
     26 
     27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     28 #pragma GCC system_header
     29 #endif
     30 
     31 _LIBCPP_BEGIN_NAMESPACE_STD
     32 
     33 
     34 #ifndef _LIBCPP_CXX03_LANG
     35 template <class _Key, class _Tp>
     36 union __hash_value_type;
     37 #else
     38 template <class _Key, class _Tp>
     39 struct __hash_value_type;
     40 #endif
     41 
     42 template <class _Key, class _Cp, class _Hash,
     43           bool =  is_empty<_Hash>::value && !__libcpp_is_final<_Hash>::value>
     44 class __unordered_map_hasher;
     45 
     46 template <class _Key, class _Cp, class _Pred,
     47           bool = is_empty<_Pred>::value && !__libcpp_is_final<_Pred>::value
     48          >
     49 class __unordered_map_equal;
     50 
     51 #ifndef _LIBCPP_CXX03_LANG
     52 template <class _Tp>
     53 struct __is_hash_value_type_imp : false_type {};
     54 
     55 template <class _Key, class _Value>
     56 struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value>> : true_type {};
     57 
     58 template <class ..._Args>
     59 struct __is_hash_value_type : false_type {};
     60 
     61 template <class _One>
     62 struct __is_hash_value_type<_One> : __is_hash_value_type_imp<typename __uncvref<_One>::type> {};
     63 #endif
     64 
     65 _LIBCPP_FUNC_VIS
     66 size_t __next_prime(size_t __n);
     67 
     68 template <class _NodePtr>
     69 struct __hash_node_base
     70 {
     71     typedef typename pointer_traits<_NodePtr>::element_type __node_type;
     72     typedef __hash_node_base __first_node;
     73     typedef typename __rebind_pointer<_NodePtr, __first_node>::type __node_base_pointer;
     74     typedef _NodePtr __node_pointer;
     75 
     76 #if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
     77   typedef __node_base_pointer __next_pointer;
     78 #else
     79   typedef typename conditional<
     80       is_pointer<__node_pointer>::value,
     81       __node_base_pointer,
     82       __node_pointer>::type   __next_pointer;
     83 #endif
     84 
     85     __next_pointer    __next_;
     86 
     87     _LIBCPP_INLINE_VISIBILITY
     88     __next_pointer __ptr() _NOEXCEPT {
     89         return static_cast<__next_pointer>(
     90             pointer_traits<__node_base_pointer>::pointer_to(*this));
     91     }
     92 
     93     _LIBCPP_INLINE_VISIBILITY
     94     __node_pointer __upcast() _NOEXCEPT {
     95         return static_cast<__node_pointer>(
     96             pointer_traits<__node_base_pointer>::pointer_to(*this));
     97     }
     98 
     99     _LIBCPP_INLINE_VISIBILITY
    100     size_t __hash() const _NOEXCEPT {
    101         return static_cast<__node_type const&>(*this).__hash_;
    102     }
    103 
    104     _LIBCPP_INLINE_VISIBILITY __hash_node_base() _NOEXCEPT : __next_(nullptr) {}
    105 };
    106 
    107 template <class _Tp, class _VoidPtr>
    108 struct __hash_node
    109     : public __hash_node_base
    110              <
    111                  typename __rebind_pointer<_VoidPtr, __hash_node<_Tp, _VoidPtr> >::type
    112              >
    113 {
    114     typedef _Tp __node_value_type;
    115 
    116     size_t            __hash_;
    117     __node_value_type __value_;
    118 };
    119 
    120 inline _LIBCPP_INLINE_VISIBILITY
    121 bool
    122 __is_hash_power2(size_t __bc)
    123 {
    124     return __bc > 2 && !(__bc & (__bc - 1));
    125 }
    126 
    127 inline _LIBCPP_INLINE_VISIBILITY
    128 size_t
    129 __constrain_hash(size_t __h, size_t __bc)
    130 {
    131     return !(__bc & (__bc - 1)) ? __h & (__bc - 1) :
    132         (__h < __bc ? __h : __h % __bc);
    133 }
    134 
    135 inline _LIBCPP_INLINE_VISIBILITY
    136 size_t
    137 __next_hash_pow2(size_t __n)
    138 {
    139     return size_t(1) << (std::numeric_limits<size_t>::digits - __clz(__n-1));
    140 }
    141 
    142 
    143 template <class _Tp, class _Hash, class _Equal, class _Alloc> class __hash_table;
    144 
    145 template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_iterator;
    146 template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
    147 template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_local_iterator;
    148 template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
    149 template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
    150 template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
    151 
    152 template <class _Tp>
    153 struct __hash_key_value_types {
    154   static_assert(!is_reference<_Tp>::value && !is_const<_Tp>::value, "");
    155   typedef _Tp key_type;
    156   typedef _Tp __node_value_type;
    157   typedef _Tp __container_value_type;
    158   static const bool __is_map = false;
    159 
    160   _LIBCPP_INLINE_VISIBILITY
    161   static key_type const& __get_key(_Tp const& __v) {
    162     return __v;
    163   }
    164   _LIBCPP_INLINE_VISIBILITY
    165   static __container_value_type const& __get_value(__node_value_type const& __v) {
    166     return __v;
    167   }
    168   _LIBCPP_INLINE_VISIBILITY
    169   static __container_value_type* __get_ptr(__node_value_type& __n) {
    170     return _VSTD::addressof(__n);
    171   }
    172 #ifndef _LIBCPP_CXX03_LANG
    173   _LIBCPP_INLINE_VISIBILITY
    174   static  __container_value_type&& __move(__node_value_type& __v) {
    175     return _VSTD::move(__v);
    176   }
    177 #endif
    178 };
    179 
    180 template <class _Key, class _Tp>
    181 struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
    182   typedef _Key                                         key_type;
    183   typedef _Tp                                          mapped_type;
    184   typedef __hash_value_type<_Key, _Tp>                 __node_value_type;
    185   typedef pair<const _Key, _Tp>                        __container_value_type;
    186   typedef pair<_Key, _Tp>                              __nc_value_type;
    187   typedef __container_value_type                       __map_value_type;
    188   static const bool __is_map = true;
    189 
    190   _LIBCPP_INLINE_VISIBILITY
    191   static key_type const& __get_key(__container_value_type const& __v) {
    192     return __v.first;
    193   }
    194 
    195   template <class _Up>
    196   _LIBCPP_INLINE_VISIBILITY
    197   static typename enable_if<__is_same_uncvref<_Up, __node_value_type>::value,
    198       __container_value_type const&>::type
    199   __get_value(_Up& __t) {
    200     return __t.__cc;
    201   }
    202 
    203   template <class _Up>
    204   _LIBCPP_INLINE_VISIBILITY
    205   static typename enable_if<__is_same_uncvref<_Up, __container_value_type>::value,
    206       __container_value_type const&>::type
    207   __get_value(_Up& __t) {
    208     return __t;
    209   }
    210 
    211   _LIBCPP_INLINE_VISIBILITY
    212   static __container_value_type* __get_ptr(__node_value_type& __n) {
    213     return _VSTD::addressof(__n.__cc);
    214   }
    215 #ifndef _LIBCPP_CXX03_LANG
    216   _LIBCPP_INLINE_VISIBILITY
    217   static __nc_value_type&& __move(__node_value_type& __v) {
    218     return _VSTD::move(__v.__nc);
    219   }
    220 #endif
    221 
    222 };
    223 
    224 template <class _Tp, class _AllocPtr, class _KVTypes = __hash_key_value_types<_Tp>,
    225           bool = _KVTypes::__is_map>
    226 struct __hash_map_pointer_types {};
    227 
    228 template <class _Tp, class _AllocPtr, class _KVTypes>
    229 struct __hash_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
    230   typedef typename _KVTypes::__map_value_type   _Mv;
    231   typedef typename __rebind_pointer<_AllocPtr, _Mv>::type
    232                                                        __map_value_type_pointer;
    233   typedef typename __rebind_pointer<_AllocPtr, const _Mv>::type
    234                                                  __const_map_value_type_pointer;
    235 };
    236 
    237 template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
    238 struct __hash_node_types;
    239 
    240 template <class _NodePtr, class _Tp, class _VoidPtr>
    241 struct __hash_node_types<_NodePtr, __hash_node<_Tp, _VoidPtr> >
    242     : public __hash_key_value_types<_Tp>, __hash_map_pointer_types<_Tp, _VoidPtr>
    243 
    244 {
    245   typedef __hash_key_value_types<_Tp>           __base;
    246 
    247 public:
    248   typedef ptrdiff_t difference_type;
    249   typedef size_t size_type;
    250 
    251   typedef typename __rebind_pointer<_NodePtr, void>::type       __void_pointer;
    252 
    253   typedef typename pointer_traits<_NodePtr>::element_type       __node_type;
    254   typedef _NodePtr                                              __node_pointer;
    255 
    256   typedef __hash_node_base<__node_pointer>                      __node_base_type;
    257   typedef typename __rebind_pointer<_NodePtr, __node_base_type>::type
    258                                                              __node_base_pointer;
    259 
    260   typedef typename __node_base_type::__next_pointer          __next_pointer;
    261 
    262   typedef _Tp                                                 __node_value_type;
    263   typedef typename __rebind_pointer<_VoidPtr, __node_value_type>::type
    264                                                       __node_value_type_pointer;
    265   typedef typename __rebind_pointer<_VoidPtr, const __node_value_type>::type
    266                                                 __const_node_value_type_pointer;
    267 
    268 private:
    269     static_assert(!is_const<__node_type>::value,
    270                 "_NodePtr should never be a pointer to const");
    271     static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
    272                   "_VoidPtr does not point to unqualified void type");
    273     static_assert((is_same<typename __rebind_pointer<_VoidPtr, __node_type>::type,
    274                           _NodePtr>::value), "_VoidPtr does not rebind to _NodePtr.");
    275 };
    276 
    277 template <class _HashIterator>
    278 struct __hash_node_types_from_iterator;
    279 template <class _NodePtr>
    280 struct __hash_node_types_from_iterator<__hash_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
    281 template <class _NodePtr>
    282 struct __hash_node_types_from_iterator<__hash_const_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
    283 template <class _NodePtr>
    284 struct __hash_node_types_from_iterator<__hash_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
    285 template <class _NodePtr>
    286 struct __hash_node_types_from_iterator<__hash_const_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
    287 
    288 
    289 template <class _NodeValueTp, class _VoidPtr>
    290 struct __make_hash_node_types {
    291   typedef __hash_node<_NodeValueTp, _VoidPtr> _NodeTp;
    292   typedef typename __rebind_pointer<_VoidPtr, _NodeTp>::type _NodePtr;
    293   typedef __hash_node_types<_NodePtr> type;
    294 };
    295 
    296 template <class _NodePtr>
    297 class _LIBCPP_TEMPLATE_VIS __hash_iterator
    298 {
    299     typedef __hash_node_types<_NodePtr> _NodeTypes;
    300     typedef _NodePtr                            __node_pointer;
    301     typedef typename _NodeTypes::__next_pointer __next_pointer;
    302 
    303     __next_pointer            __node_;
    304 
    305 public:
    306     typedef forward_iterator_tag                           iterator_category;
    307     typedef typename _NodeTypes::__node_value_type         value_type;
    308     typedef typename _NodeTypes::difference_type           difference_type;
    309     typedef value_type&                                    reference;
    310     typedef typename _NodeTypes::__node_value_type_pointer pointer;
    311 
    312     _LIBCPP_INLINE_VISIBILITY __hash_iterator() _NOEXCEPT : __node_(nullptr) {
    313         _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
    314     }
    315 
    316 #if _LIBCPP_DEBUG_LEVEL >= 2
    317     _LIBCPP_INLINE_VISIBILITY
    318     __hash_iterator(const __hash_iterator& __i)
    319         : __node_(__i.__node_)
    320     {
    321         __get_db()->__iterator_copy(this, &__i);
    322     }
    323 
    324     _LIBCPP_INLINE_VISIBILITY
    325     ~__hash_iterator()
    326     {
    327         __get_db()->__erase_i(this);
    328     }
    329 
    330     _LIBCPP_INLINE_VISIBILITY
    331     __hash_iterator& operator=(const __hash_iterator& __i)
    332     {
    333         if (this != &__i)
    334         {
    335             __get_db()->__iterator_copy(this, &__i);
    336             __node_ = __i.__node_;
    337         }
    338         return *this;
    339     }
    340 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
    341 
    342     _LIBCPP_INLINE_VISIBILITY
    343     reference operator*() const {
    344         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    345                              "Attempted to dereference a non-dereferenceable unordered container iterator");
    346         return __node_->__upcast()->__value_;
    347     }
    348 
    349     _LIBCPP_INLINE_VISIBILITY
    350     pointer operator->() const {
    351         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    352                            "Attempted to dereference a non-dereferenceable unordered container iterator");
    353         return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
    354     }
    355 
    356     _LIBCPP_INLINE_VISIBILITY
    357     __hash_iterator& operator++() {
    358         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    359                        "Attempted to increment non-incrementable unordered container iterator");
    360         __node_ = __node_->__next_;
    361         return *this;
    362     }
    363 
    364     _LIBCPP_INLINE_VISIBILITY
    365     __hash_iterator operator++(int)
    366     {
    367         __hash_iterator __t(*this);
    368         ++(*this);
    369         return __t;
    370     }
    371 
    372     friend _LIBCPP_INLINE_VISIBILITY
    373     bool operator==(const __hash_iterator& __x, const __hash_iterator& __y)
    374     {
    375         return __x.__node_ == __y.__node_;
    376     }
    377     friend _LIBCPP_INLINE_VISIBILITY
    378     bool operator!=(const __hash_iterator& __x, const __hash_iterator& __y)
    379         {return !(__x == __y);}
    380 
    381 private:
    382 #if _LIBCPP_DEBUG_LEVEL >= 2
    383     _LIBCPP_INLINE_VISIBILITY
    384     __hash_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
    385         : __node_(__node)
    386         {
    387             __get_db()->__insert_ic(this, __c);
    388         }
    389 #else
    390     _LIBCPP_INLINE_VISIBILITY
    391     __hash_iterator(__next_pointer __node) _NOEXCEPT
    392         : __node_(__node)
    393         {}
    394 #endif
    395     template <class, class, class, class> friend class __hash_table;
    396     template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
    397     template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
    398     template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
    399     template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
    400 };
    401 
    402 template <class _NodePtr>
    403 class _LIBCPP_TEMPLATE_VIS __hash_const_iterator
    404 {
    405     static_assert(!is_const<typename pointer_traits<_NodePtr>::element_type>::value, "");
    406     typedef __hash_node_types<_NodePtr> _NodeTypes;
    407     typedef _NodePtr                            __node_pointer;
    408     typedef typename _NodeTypes::__next_pointer __next_pointer;
    409 
    410     __next_pointer __node_;
    411 
    412 public:
    413     typedef __hash_iterator<_NodePtr> __non_const_iterator;
    414 
    415     typedef forward_iterator_tag                                 iterator_category;
    416     typedef typename _NodeTypes::__node_value_type               value_type;
    417     typedef typename _NodeTypes::difference_type                 difference_type;
    418     typedef const value_type&                                    reference;
    419     typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
    420 
    421 
    422     _LIBCPP_INLINE_VISIBILITY __hash_const_iterator() _NOEXCEPT : __node_(nullptr) {
    423         _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
    424     }
    425 
    426     _LIBCPP_INLINE_VISIBILITY 
    427     __hash_const_iterator(const __non_const_iterator& __x) _NOEXCEPT
    428         : __node_(__x.__node_)
    429     {
    430         _LIBCPP_DEBUG_MODE(__get_db()->__iterator_copy(this, &__x));
    431     }
    432 
    433 #if _LIBCPP_DEBUG_LEVEL >= 2
    434     _LIBCPP_INLINE_VISIBILITY
    435     __hash_const_iterator(const __hash_const_iterator& __i)
    436         : __node_(__i.__node_)
    437     {
    438         __get_db()->__iterator_copy(this, &__i);
    439     }
    440 
    441     _LIBCPP_INLINE_VISIBILITY
    442     ~__hash_const_iterator()
    443     {
    444         __get_db()->__erase_i(this);
    445     }
    446 
    447     _LIBCPP_INLINE_VISIBILITY
    448     __hash_const_iterator& operator=(const __hash_const_iterator& __i)
    449     {
    450         if (this != &__i)
    451         {
    452             __get_db()->__iterator_copy(this, &__i);
    453             __node_ = __i.__node_;
    454         }
    455         return *this;
    456     }
    457 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
    458 
    459     _LIBCPP_INLINE_VISIBILITY
    460     reference operator*() const {
    461         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    462                            "Attempted to dereference a non-dereferenceable unordered container const_iterator");
    463         return __node_->__upcast()->__value_;
    464     }
    465     _LIBCPP_INLINE_VISIBILITY
    466     pointer operator->() const {
    467         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    468                            "Attempted to dereference a non-dereferenceable unordered container const_iterator");
    469         return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
    470     }
    471 
    472     _LIBCPP_INLINE_VISIBILITY
    473     __hash_const_iterator& operator++() {
    474         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    475                              "Attempted to increment non-incrementable unordered container const_iterator");
    476         __node_ = __node_->__next_;
    477         return *this;
    478     }
    479 
    480     _LIBCPP_INLINE_VISIBILITY
    481     __hash_const_iterator operator++(int)
    482     {
    483         __hash_const_iterator __t(*this);
    484         ++(*this);
    485         return __t;
    486     }
    487 
    488     friend _LIBCPP_INLINE_VISIBILITY
    489     bool operator==(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
    490     {
    491         return __x.__node_ == __y.__node_;
    492     }
    493     friend _LIBCPP_INLINE_VISIBILITY
    494     bool operator!=(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
    495         {return !(__x == __y);}
    496 
    497 private:
    498 #if _LIBCPP_DEBUG_LEVEL >= 2
    499     _LIBCPP_INLINE_VISIBILITY
    500     __hash_const_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
    501         : __node_(__node)
    502         {
    503             __get_db()->__insert_ic(this, __c);
    504         }
    505 #else
    506     _LIBCPP_INLINE_VISIBILITY
    507     __hash_const_iterator(__next_pointer __node) _NOEXCEPT
    508         : __node_(__node)
    509         {}
    510 #endif
    511     template <class, class, class, class> friend class __hash_table;
    512     template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
    513     template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
    514     template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
    515 };
    516 
    517 template <class _NodePtr>
    518 class _LIBCPP_TEMPLATE_VIS __hash_local_iterator
    519 {
    520     typedef __hash_node_types<_NodePtr> _NodeTypes;
    521     typedef _NodePtr                            __node_pointer;
    522     typedef typename _NodeTypes::__next_pointer __next_pointer;
    523 
    524     __next_pointer         __node_;
    525     size_t                 __bucket_;
    526     size_t                 __bucket_count_;
    527 
    528 public:
    529     typedef forward_iterator_tag                                iterator_category;
    530     typedef typename _NodeTypes::__node_value_type              value_type;
    531     typedef typename _NodeTypes::difference_type                difference_type;
    532     typedef value_type&                                         reference;
    533     typedef typename _NodeTypes::__node_value_type_pointer      pointer;
    534 
    535     _LIBCPP_INLINE_VISIBILITY __hash_local_iterator() _NOEXCEPT : __node_(nullptr) {
    536         _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
    537     }
    538 
    539 #if _LIBCPP_DEBUG_LEVEL >= 2
    540     _LIBCPP_INLINE_VISIBILITY
    541     __hash_local_iterator(const __hash_local_iterator& __i)
    542         : __node_(__i.__node_),
    543           __bucket_(__i.__bucket_),
    544           __bucket_count_(__i.__bucket_count_)
    545     {
    546         __get_db()->__iterator_copy(this, &__i);
    547     }
    548 
    549     _LIBCPP_INLINE_VISIBILITY
    550     ~__hash_local_iterator()
    551     {
    552         __get_db()->__erase_i(this);
    553     }
    554 
    555     _LIBCPP_INLINE_VISIBILITY
    556     __hash_local_iterator& operator=(const __hash_local_iterator& __i)
    557     {
    558         if (this != &__i)
    559         {
    560             __get_db()->__iterator_copy(this, &__i);
    561             __node_ = __i.__node_;
    562             __bucket_ = __i.__bucket_;
    563             __bucket_count_ = __i.__bucket_count_;
    564         }
    565         return *this;
    566     }
    567 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
    568 
    569     _LIBCPP_INLINE_VISIBILITY
    570     reference operator*() const {
    571         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    572                            "Attempted to dereference a non-dereferenceable unordered container local_iterator");
    573         return __node_->__upcast()->__value_;
    574     }
    575 
    576     _LIBCPP_INLINE_VISIBILITY
    577     pointer operator->() const {
    578         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    579                              "Attempted to dereference a non-dereferenceable unordered container local_iterator");
    580         return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
    581     }
    582 
    583     _LIBCPP_INLINE_VISIBILITY
    584     __hash_local_iterator& operator++() {
    585         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    586                        "Attempted to increment non-incrementable unordered container local_iterator");
    587         __node_ = __node_->__next_;
    588         if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
    589             __node_ = nullptr;
    590         return *this;
    591     }
    592 
    593     _LIBCPP_INLINE_VISIBILITY
    594     __hash_local_iterator operator++(int)
    595     {
    596         __hash_local_iterator __t(*this);
    597         ++(*this);
    598         return __t;
    599     }
    600 
    601     friend _LIBCPP_INLINE_VISIBILITY
    602     bool operator==(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
    603     {
    604         return __x.__node_ == __y.__node_;
    605     }
    606     friend _LIBCPP_INLINE_VISIBILITY
    607     bool operator!=(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
    608         {return !(__x == __y);}
    609 
    610 private:
    611 #if _LIBCPP_DEBUG_LEVEL >= 2
    612     _LIBCPP_INLINE_VISIBILITY
    613     __hash_local_iterator(__next_pointer __node, size_t __bucket,
    614                           size_t __bucket_count, const void* __c) _NOEXCEPT
    615         : __node_(__node),
    616           __bucket_(__bucket),
    617           __bucket_count_(__bucket_count)
    618         {
    619             __get_db()->__insert_ic(this, __c);
    620             if (__node_ != nullptr)
    621                 __node_ = __node_->__next_;
    622         }
    623 #else
    624     _LIBCPP_INLINE_VISIBILITY
    625     __hash_local_iterator(__next_pointer __node, size_t __bucket,
    626                           size_t __bucket_count) _NOEXCEPT
    627         : __node_(__node),
    628           __bucket_(__bucket),
    629           __bucket_count_(__bucket_count)
    630         {
    631             if (__node_ != nullptr)
    632                 __node_ = __node_->__next_;
    633         }
    634 #endif
    635     template <class, class, class, class> friend class __hash_table;
    636     template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
    637     template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
    638 };
    639 
    640 template <class _ConstNodePtr>
    641 class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator
    642 {
    643     typedef __hash_node_types<_ConstNodePtr> _NodeTypes;
    644     typedef _ConstNodePtr                       __node_pointer;
    645     typedef typename _NodeTypes::__next_pointer __next_pointer;
    646 
    647     __next_pointer         __node_;
    648     size_t                 __bucket_;
    649     size_t                 __bucket_count_;
    650 
    651     typedef pointer_traits<__node_pointer>          __pointer_traits;
    652     typedef typename __pointer_traits::element_type __node;
    653     typedef typename remove_const<__node>::type     __non_const_node;
    654     typedef typename __rebind_pointer<__node_pointer, __non_const_node>::type
    655         __non_const_node_pointer;
    656 public:
    657     typedef __hash_local_iterator<__non_const_node_pointer>
    658                                                     __non_const_iterator;
    659 
    660     typedef forward_iterator_tag                                 iterator_category;
    661     typedef typename _NodeTypes::__node_value_type               value_type;
    662     typedef typename _NodeTypes::difference_type                 difference_type;
    663     typedef const value_type&                                    reference;
    664     typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
    665 
    666 
    667     _LIBCPP_INLINE_VISIBILITY __hash_const_local_iterator() _NOEXCEPT : __node_(nullptr) {
    668         _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
    669     }
    670 
    671     _LIBCPP_INLINE_VISIBILITY
    672     __hash_const_local_iterator(const __non_const_iterator& __x) _NOEXCEPT
    673         : __node_(__x.__node_),
    674           __bucket_(__x.__bucket_),
    675           __bucket_count_(__x.__bucket_count_)
    676     {
    677         _LIBCPP_DEBUG_MODE(__get_db()->__iterator_copy(this, &__x));
    678     }
    679 
    680 #if _LIBCPP_DEBUG_LEVEL >= 2
    681     _LIBCPP_INLINE_VISIBILITY
    682     __hash_const_local_iterator(const __hash_const_local_iterator& __i)
    683         : __node_(__i.__node_),
    684           __bucket_(__i.__bucket_),
    685           __bucket_count_(__i.__bucket_count_)
    686     {
    687         __get_db()->__iterator_copy(this, &__i);
    688     }
    689 
    690     _LIBCPP_INLINE_VISIBILITY
    691     ~__hash_const_local_iterator()
    692     {
    693         __get_db()->__erase_i(this);
    694     }
    695 
    696     _LIBCPP_INLINE_VISIBILITY
    697     __hash_const_local_iterator& operator=(const __hash_const_local_iterator& __i)
    698     {
    699         if (this != &__i)
    700         {
    701             __get_db()->__iterator_copy(this, &__i);
    702             __node_ = __i.__node_;
    703             __bucket_ = __i.__bucket_;
    704             __bucket_count_ = __i.__bucket_count_;
    705         }
    706         return *this;
    707     }
    708 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
    709 
    710     _LIBCPP_INLINE_VISIBILITY
    711     reference operator*() const {
    712         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    713                            "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
    714         return __node_->__upcast()->__value_;
    715     }
    716 
    717     _LIBCPP_INLINE_VISIBILITY
    718     pointer operator->() const {
    719         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    720                            "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
    721         return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
    722     }
    723 
    724     _LIBCPP_INLINE_VISIBILITY
    725     __hash_const_local_iterator& operator++() {
    726         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
    727                        "Attempted to increment non-incrementable unordered container const_local_iterator");
    728         __node_ = __node_->__next_;
    729         if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
    730             __node_ = nullptr;
    731         return *this;
    732     }
    733 
    734     _LIBCPP_INLINE_VISIBILITY
    735     __hash_const_local_iterator operator++(int)
    736     {
    737         __hash_const_local_iterator __t(*this);
    738         ++(*this);
    739         return __t;
    740     }
    741 
    742     friend _LIBCPP_INLINE_VISIBILITY
    743     bool operator==(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
    744     {
    745         return __x.__node_ == __y.__node_;
    746     }
    747     friend _LIBCPP_INLINE_VISIBILITY
    748     bool operator!=(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
    749         {return !(__x == __y);}
    750 
    751 private:
    752 #if _LIBCPP_DEBUG_LEVEL >= 2
    753     _LIBCPP_INLINE_VISIBILITY
    754     __hash_const_local_iterator(__next_pointer __node, size_t __bucket,
    755                                 size_t __bucket_count, const void* __c) _NOEXCEPT
    756         : __node_(__node),
    757           __bucket_(__bucket),
    758           __bucket_count_(__bucket_count)
    759         {
    760             __get_db()->__insert_ic(this, __c);
    761             if (__node_ != nullptr)
    762                 __node_ = __node_->__next_;
    763         }
    764 #else
    765     _LIBCPP_INLINE_VISIBILITY
    766     __hash_const_local_iterator(__next_pointer __node, size_t __bucket,
    767                                 size_t __bucket_count) _NOEXCEPT
    768         : __node_(__node),
    769           __bucket_(__bucket),
    770           __bucket_count_(__bucket_count)
    771         {
    772             if (__node_ != nullptr)
    773                 __node_ = __node_->__next_;
    774         }
    775 #endif
    776     template <class, class, class, class> friend class __hash_table;
    777     template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
    778 };
    779 
    780 template <class _Alloc>
    781 class __bucket_list_deallocator
    782 {
    783     typedef _Alloc                                          allocator_type;
    784     typedef allocator_traits<allocator_type>                __alloc_traits;
    785     typedef typename __alloc_traits::size_type              size_type;
    786 
    787     __compressed_pair<size_type, allocator_type> __data_;
    788 public:
    789     typedef typename __alloc_traits::pointer pointer;
    790 
    791     _LIBCPP_INLINE_VISIBILITY
    792     __bucket_list_deallocator()
    793         _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
    794         : __data_(0) {}
    795 
    796     _LIBCPP_INLINE_VISIBILITY
    797     __bucket_list_deallocator(const allocator_type& __a, size_type __size)
    798         _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
    799         : __data_(__size, __a) {}
    800 
    801 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    802 
    803     _LIBCPP_INLINE_VISIBILITY
    804     __bucket_list_deallocator(__bucket_list_deallocator&& __x)
    805         _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
    806         : __data_(_VSTD::move(__x.__data_))
    807     {
    808         __x.size() = 0;
    809     }
    810 
    811 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    812 
    813     _LIBCPP_INLINE_VISIBILITY
    814     size_type& size() _NOEXCEPT {return __data_.first();}
    815     _LIBCPP_INLINE_VISIBILITY
    816     size_type  size() const _NOEXCEPT {return __data_.first();}
    817 
    818     _LIBCPP_INLINE_VISIBILITY
    819     allocator_type& __alloc() _NOEXCEPT {return __data_.second();}
    820     _LIBCPP_INLINE_VISIBILITY
    821     const allocator_type& __alloc() const _NOEXCEPT {return __data_.second();}
    822 
    823     _LIBCPP_INLINE_VISIBILITY
    824     void operator()(pointer __p) _NOEXCEPT
    825     {
    826         __alloc_traits::deallocate(__alloc(), __p, size());
    827     }
    828 };
    829 
    830 template <class _Alloc> class __hash_map_node_destructor;
    831 
    832 template <class _Alloc>
    833 class __hash_node_destructor
    834 {
    835     typedef _Alloc                                          allocator_type;
    836     typedef allocator_traits<allocator_type>                __alloc_traits;
    837 
    838 public:
    839     typedef typename __alloc_traits::pointer                pointer;
    840 private:
    841     typedef __hash_node_types<pointer> _NodeTypes;
    842 
    843     allocator_type& __na_;
    844 
    845     __hash_node_destructor& operator=(const __hash_node_destructor&);
    846 
    847 public:
    848     bool __value_constructed;
    849 
    850     _LIBCPP_INLINE_VISIBILITY
    851     explicit __hash_node_destructor(allocator_type& __na,
    852                                     bool __constructed = false) _NOEXCEPT
    853         : __na_(__na),
    854           __value_constructed(__constructed)
    855         {}
    856 
    857     _LIBCPP_INLINE_VISIBILITY
    858     void operator()(pointer __p) _NOEXCEPT
    859     {
    860         if (__value_constructed)
    861             __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
    862         if (__p)
    863             __alloc_traits::deallocate(__na_, __p, 1);
    864     }
    865 
    866     template <class> friend class __hash_map_node_destructor;
    867 };
    868 
    869 
    870 #ifndef _LIBCPP_CXX03_LANG
    871 template <class _Key, class _Hash, class _Equal, class _Alloc>
    872 struct __diagnose_hash_table_helper {
    873   static constexpr bool __trigger_diagnostics()
    874     _LIBCPP_DIAGNOSE_WARNING(__check_hash_requirements<_Key, _Hash>::value
    875                          && !__invokable<_Hash const&, _Key const&>::value,
    876       "the specified hash functor does not provide a const call operator")
    877     _LIBCPP_DIAGNOSE_WARNING(is_copy_constructible<_Equal>::value
    878                           && !__invokable<_Equal const&, _Key const&, _Key const&>::value,
    879       "the specified comparator type does not provide a const call operator")
    880   {
    881     static_assert(__check_hash_requirements<_Key, _Hash>::value,
    882       "the specified hash does not meet the Hash requirements");
    883     static_assert(is_copy_constructible<_Equal>::value,
    884       "the specified comparator is required to be copy constructible");
    885     return true;
    886   }
    887 };
    888 
    889 template <class _Key, class _Value, class _Hash, class _Equal, class _Alloc>
    890 struct __diagnose_hash_table_helper<
    891   __hash_value_type<_Key, _Value>,
    892   __unordered_map_hasher<_Key, __hash_value_type<_Key, _Value>, _Hash>,
    893   __unordered_map_equal<_Key, __hash_value_type<_Key, _Value>, _Equal>,
    894   _Alloc>
    895 : __diagnose_hash_table_helper<_Key, _Hash, _Equal, _Alloc>
    896 {
    897 };
    898 #endif // _LIBCPP_CXX03_LANG
    899 
    900 template <class _Tp, class _Hash, class _Equal, class _Alloc>
    901 class __hash_table
    902 {
    903 public:
    904     typedef _Tp    value_type;
    905     typedef _Hash  hasher;
    906     typedef _Equal key_equal;
    907     typedef _Alloc allocator_type;
    908 
    909 private:
    910     typedef allocator_traits<allocator_type> __alloc_traits;
    911     typedef typename
    912       __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type
    913                                                                      _NodeTypes;
    914 public:
    915 
    916     typedef typename _NodeTypes::__node_value_type           __node_value_type;
    917     typedef typename _NodeTypes::__container_value_type      __container_value_type;
    918     typedef typename _NodeTypes::key_type                    key_type;
    919     typedef value_type&                              reference;
    920     typedef const value_type&                        const_reference;
    921     typedef typename __alloc_traits::pointer         pointer;
    922     typedef typename __alloc_traits::const_pointer   const_pointer;
    923 #ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
    924     typedef typename __alloc_traits::size_type       size_type;
    925 #else
    926     typedef typename _NodeTypes::size_type           size_type;
    927 #endif
    928     typedef typename _NodeTypes::difference_type     difference_type;
    929 public:
    930     // Create __node
    931 
    932     typedef typename _NodeTypes::__node_type __node;
    933     typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
    934     typedef allocator_traits<__node_allocator>       __node_traits;
    935     typedef typename _NodeTypes::__void_pointer      __void_pointer;
    936     typedef typename _NodeTypes::__node_pointer      __node_pointer;
    937     typedef typename _NodeTypes::__node_pointer      __node_const_pointer;
    938     typedef typename _NodeTypes::__node_base_type    __first_node;
    939     typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
    940     typedef typename _NodeTypes::__next_pointer      __next_pointer;
    941 
    942 private:
    943     // check for sane allocator pointer rebinding semantics. Rebinding the
    944     // allocator for a new pointer type should be exactly the same as rebinding
    945     // the pointer using 'pointer_traits'.
    946     static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
    947                   "Allocator does not rebind pointers in a sane manner.");
    948     typedef typename __rebind_alloc_helper<__node_traits, __first_node>::type
    949         __node_base_allocator;
    950     typedef allocator_traits<__node_base_allocator> __node_base_traits;
    951     static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
    952                  "Allocator does not rebind pointers in a sane manner.");
    953 
    954 private:
    955 
    956     typedef typename __rebind_alloc_helper<__node_traits, __next_pointer>::type __pointer_allocator;
    957     typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
    958     typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
    959     typedef allocator_traits<__pointer_allocator>          __pointer_alloc_traits;
    960     typedef typename __bucket_list_deleter::pointer       __node_pointer_pointer;
    961 
    962 #ifndef _LIBCPP_CXX03_LANG
    963     static_assert(__diagnose_hash_table_helper<_Tp, _Hash, _Equal, _Alloc>::__trigger_diagnostics(), "");
    964 #endif
    965 
    966     // --- Member data begin ---
    967     __bucket_list                                         __bucket_list_;
    968     __compressed_pair<__first_node, __node_allocator>     __p1_;
    969     __compressed_pair<size_type, hasher>                  __p2_;
    970     __compressed_pair<float, key_equal>                   __p3_;
    971     // --- Member data end ---
    972 
    973     _LIBCPP_INLINE_VISIBILITY
    974     size_type& size() _NOEXCEPT {return __p2_.first();}
    975 public:
    976     _LIBCPP_INLINE_VISIBILITY
    977     size_type  size() const _NOEXCEPT {return __p2_.first();}
    978 
    979     _LIBCPP_INLINE_VISIBILITY
    980     hasher& hash_function() _NOEXCEPT {return __p2_.second();}
    981     _LIBCPP_INLINE_VISIBILITY
    982     const hasher& hash_function() const _NOEXCEPT {return __p2_.second();}
    983 
    984     _LIBCPP_INLINE_VISIBILITY
    985     float& max_load_factor() _NOEXCEPT {return __p3_.first();}
    986     _LIBCPP_INLINE_VISIBILITY
    987     float  max_load_factor() const _NOEXCEPT {return __p3_.first();}
    988 
    989     _LIBCPP_INLINE_VISIBILITY
    990     key_equal& key_eq() _NOEXCEPT {return __p3_.second();}
    991     _LIBCPP_INLINE_VISIBILITY
    992     const key_equal& key_eq() const _NOEXCEPT {return __p3_.second();}
    993 
    994     _LIBCPP_INLINE_VISIBILITY
    995     __node_allocator& __node_alloc() _NOEXCEPT {return __p1_.second();}
    996     _LIBCPP_INLINE_VISIBILITY
    997     const __node_allocator& __node_alloc() const _NOEXCEPT
    998         {return __p1_.second();}
    999 
   1000 public:
   1001     typedef __hash_iterator<__node_pointer>                   iterator;
   1002     typedef __hash_const_iterator<__node_pointer>             const_iterator;
   1003     typedef __hash_local_iterator<__node_pointer>             local_iterator;
   1004     typedef __hash_const_local_iterator<__node_pointer>       const_local_iterator;
   1005 
   1006     _LIBCPP_INLINE_VISIBILITY
   1007     __hash_table()
   1008         _NOEXCEPT_(
   1009             is_nothrow_default_constructible<__bucket_list>::value &&
   1010             is_nothrow_default_constructible<__first_node>::value &&
   1011             is_nothrow_default_constructible<__node_allocator>::value &&
   1012             is_nothrow_default_constructible<hasher>::value &&
   1013             is_nothrow_default_constructible<key_equal>::value);
   1014     _LIBCPP_INLINE_VISIBILITY
   1015     __hash_table(const hasher& __hf, const key_equal& __eql);
   1016     __hash_table(const hasher& __hf, const key_equal& __eql,
   1017                  const allocator_type& __a);
   1018     explicit __hash_table(const allocator_type& __a);
   1019     __hash_table(const __hash_table& __u);
   1020     __hash_table(const __hash_table& __u, const allocator_type& __a);
   1021 #ifndef _LIBCPP_CXX03_LANG
   1022     __hash_table(__hash_table&& __u)
   1023         _NOEXCEPT_(
   1024             is_nothrow_move_constructible<__bucket_list>::value &&
   1025             is_nothrow_move_constructible<__first_node>::value &&
   1026             is_nothrow_move_constructible<__node_allocator>::value &&
   1027             is_nothrow_move_constructible<hasher>::value &&
   1028             is_nothrow_move_constructible<key_equal>::value);
   1029     __hash_table(__hash_table&& __u, const allocator_type& __a);
   1030 #endif  // _LIBCPP_CXX03_LANG
   1031     ~__hash_table();
   1032 
   1033     __hash_table& operator=(const __hash_table& __u);
   1034 #ifndef _LIBCPP_CXX03_LANG
   1035     _LIBCPP_INLINE_VISIBILITY
   1036     __hash_table& operator=(__hash_table&& __u)
   1037         _NOEXCEPT_(
   1038             __node_traits::propagate_on_container_move_assignment::value &&
   1039             is_nothrow_move_assignable<__node_allocator>::value &&
   1040             is_nothrow_move_assignable<hasher>::value &&
   1041             is_nothrow_move_assignable<key_equal>::value);
   1042 #endif
   1043     template <class _InputIterator>
   1044         void __assign_unique(_InputIterator __first, _InputIterator __last);
   1045     template <class _InputIterator>
   1046         void __assign_multi(_InputIterator __first, _InputIterator __last);
   1047 
   1048     _LIBCPP_INLINE_VISIBILITY
   1049     size_type max_size() const _NOEXCEPT
   1050     {
   1051         return std::min<size_type>(
   1052             __node_traits::max_size(__node_alloc()),
   1053             numeric_limits<difference_type >::max()
   1054         );
   1055     }
   1056 
   1057     pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
   1058     iterator             __node_insert_multi(__node_pointer __nd);
   1059     iterator             __node_insert_multi(const_iterator __p,
   1060                                              __node_pointer __nd);
   1061 
   1062 #ifndef _LIBCPP_CXX03_LANG
   1063     template <class _Key, class ..._Args>
   1064     _LIBCPP_INLINE_VISIBILITY
   1065     pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
   1066 
   1067     template <class... _Args>
   1068     _LIBCPP_INLINE_VISIBILITY
   1069     pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
   1070 
   1071     template <class _Pp>
   1072     _LIBCPP_INLINE_VISIBILITY
   1073     pair<iterator, bool> __emplace_unique(_Pp&& __x) {
   1074       return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
   1075                                           __can_extract_key<_Pp, key_type>());
   1076     }
   1077 
   1078     template <class _First, class _Second>
   1079     _LIBCPP_INLINE_VISIBILITY
   1080     typename enable_if<
   1081         __can_extract_map_key<_First, key_type, __container_value_type>::value,
   1082         pair<iterator, bool>
   1083     >::type __emplace_unique(_First&& __f, _Second&& __s) {
   1084         return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
   1085                                               _VSTD::forward<_Second>(__s));
   1086     }
   1087 
   1088     template <class... _Args>
   1089     _LIBCPP_INLINE_VISIBILITY
   1090     pair<iterator, bool> __emplace_unique(_Args&&... __args) {
   1091       return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
   1092     }
   1093 
   1094     template <class _Pp>
   1095     _LIBCPP_INLINE_VISIBILITY
   1096     pair<iterator, bool>
   1097     __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
   1098       return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
   1099     }
   1100     template <class _Pp>
   1101     _LIBCPP_INLINE_VISIBILITY
   1102     pair<iterator, bool>
   1103     __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
   1104       return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
   1105     }
   1106     template <class _Pp>
   1107     _LIBCPP_INLINE_VISIBILITY
   1108     pair<iterator, bool>
   1109     __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
   1110       return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
   1111     }
   1112 
   1113     template <class... _Args>
   1114     _LIBCPP_INLINE_VISIBILITY
   1115     iterator __emplace_multi(_Args&&... __args);
   1116     template <class... _Args>
   1117     _LIBCPP_INLINE_VISIBILITY
   1118     iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
   1119 
   1120 
   1121     _LIBCPP_INLINE_VISIBILITY
   1122     pair<iterator, bool>
   1123     __insert_unique(__container_value_type&& __x) {
   1124       return __emplace_unique_key_args(_NodeTypes::__get_key(__x), _VSTD::move(__x));
   1125     }
   1126 
   1127     template <class _Pp, class = typename enable_if<
   1128             !__is_same_uncvref<_Pp, __container_value_type>::value
   1129         >::type>
   1130     _LIBCPP_INLINE_VISIBILITY
   1131     pair<iterator, bool> __insert_unique(_Pp&& __x) {
   1132       return __emplace_unique(_VSTD::forward<_Pp>(__x));
   1133     }
   1134 
   1135     template <class _Pp>
   1136     _LIBCPP_INLINE_VISIBILITY
   1137     iterator __insert_multi(_Pp&& __x) {
   1138       return __emplace_multi(_VSTD::forward<_Pp>(__x));
   1139     }
   1140 
   1141     template <class _Pp>
   1142     _LIBCPP_INLINE_VISIBILITY
   1143     iterator __insert_multi(const_iterator __p, _Pp&& __x) {
   1144         return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
   1145     }
   1146 
   1147 #else  // !defined(_LIBCPP_CXX03_LANG)
   1148     template <class _Key, class _Args>
   1149     _LIBCPP_INLINE_VISIBILITY
   1150     pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args& __args);
   1151 
   1152     iterator __insert_multi(const __container_value_type& __x);
   1153     iterator __insert_multi(const_iterator __p, const __container_value_type& __x);
   1154 #endif
   1155 
   1156     _LIBCPP_INLINE_VISIBILITY
   1157     pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
   1158         return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
   1159     }
   1160 
   1161     void clear() _NOEXCEPT;
   1162     void rehash(size_type __n);
   1163     _LIBCPP_INLINE_VISIBILITY void reserve(size_type __n)
   1164         {rehash(static_cast<size_type>(ceil(__n / max_load_factor())));}
   1165 
   1166     _LIBCPP_INLINE_VISIBILITY
   1167     size_type bucket_count() const _NOEXCEPT
   1168     {
   1169         return __bucket_list_.get_deleter().size();
   1170     }
   1171 
   1172     _LIBCPP_INLINE_VISIBILITY
   1173     iterator       begin() _NOEXCEPT;
   1174     _LIBCPP_INLINE_VISIBILITY
   1175     iterator       end() _NOEXCEPT;
   1176     _LIBCPP_INLINE_VISIBILITY
   1177     const_iterator begin() const _NOEXCEPT;
   1178     _LIBCPP_INLINE_VISIBILITY
   1179     const_iterator end() const _NOEXCEPT;
   1180 
   1181     template <class _Key>
   1182         _LIBCPP_INLINE_VISIBILITY
   1183         size_type bucket(const _Key& __k) const
   1184         {
   1185             _LIBCPP_ASSERT(bucket_count() > 0,
   1186                 "unordered container::bucket(key) called when bucket_count() == 0");
   1187             return __constrain_hash(hash_function()(__k), bucket_count());
   1188         }
   1189 
   1190     template <class _Key>
   1191         iterator       find(const _Key& __x);
   1192     template <class _Key>
   1193         const_iterator find(const _Key& __x) const;
   1194 
   1195     typedef __hash_node_destructor<__node_allocator> _Dp;
   1196     typedef unique_ptr<__node, _Dp> __node_holder;
   1197 
   1198     iterator erase(const_iterator __p);
   1199     iterator erase(const_iterator __first, const_iterator __last);
   1200     template <class _Key>
   1201         size_type __erase_unique(const _Key& __k);
   1202     template <class _Key>
   1203         size_type __erase_multi(const _Key& __k);
   1204     __node_holder remove(const_iterator __p) _NOEXCEPT;
   1205 
   1206     template <class _Key>
   1207         _LIBCPP_INLINE_VISIBILITY
   1208         size_type __count_unique(const _Key& __k) const;
   1209     template <class _Key>
   1210         size_type __count_multi(const _Key& __k) const;
   1211 
   1212     template <class _Key>
   1213         pair<iterator, iterator>
   1214         __equal_range_unique(const _Key& __k);
   1215     template <class _Key>
   1216         pair<const_iterator, const_iterator>
   1217         __equal_range_unique(const _Key& __k) const;
   1218 
   1219     template <class _Key>
   1220         pair<iterator, iterator>
   1221         __equal_range_multi(const _Key& __k);
   1222     template <class _Key>
   1223         pair<const_iterator, const_iterator>
   1224         __equal_range_multi(const _Key& __k) const;
   1225 
   1226     void swap(__hash_table& __u)
   1227 #if _LIBCPP_STD_VER <= 11
   1228         _NOEXCEPT_DEBUG_(
   1229             __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
   1230             && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
   1231                   || __is_nothrow_swappable<__pointer_allocator>::value)
   1232             && (!__node_traits::propagate_on_container_swap::value
   1233                   || __is_nothrow_swappable<__node_allocator>::value)
   1234             );
   1235 #else
   1236      _NOEXCEPT_DEBUG_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value);
   1237 #endif
   1238 
   1239     _LIBCPP_INLINE_VISIBILITY
   1240     size_type max_bucket_count() const _NOEXCEPT
   1241         {return max_size(); }
   1242     size_type bucket_size(size_type __n) const;
   1243     _LIBCPP_INLINE_VISIBILITY float load_factor() const _NOEXCEPT
   1244     {
   1245         size_type __bc = bucket_count();
   1246         return __bc != 0 ? (float)size() / __bc : 0.f;
   1247     }
   1248     _LIBCPP_INLINE_VISIBILITY void max_load_factor(float __mlf) _NOEXCEPT
   1249     {
   1250         _LIBCPP_ASSERT(__mlf > 0,
   1251             "unordered container::max_load_factor(lf) called with lf <= 0");
   1252         max_load_factor() = _VSTD::max(__mlf, load_factor());
   1253     }
   1254 
   1255     _LIBCPP_INLINE_VISIBILITY
   1256     local_iterator
   1257     begin(size_type __n)
   1258     {
   1259         _LIBCPP_ASSERT(__n < bucket_count(),
   1260             "unordered container::begin(n) called with n >= bucket_count()");
   1261 #if _LIBCPP_DEBUG_LEVEL >= 2
   1262         return local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
   1263 #else
   1264         return local_iterator(__bucket_list_[__n], __n, bucket_count());
   1265 #endif
   1266     }
   1267 
   1268     _LIBCPP_INLINE_VISIBILITY
   1269     local_iterator
   1270     end(size_type __n)
   1271     {
   1272         _LIBCPP_ASSERT(__n < bucket_count(),
   1273             "unordered container::end(n) called with n >= bucket_count()");
   1274 #if _LIBCPP_DEBUG_LEVEL >= 2
   1275         return local_iterator(nullptr, __n, bucket_count(), this);
   1276 #else
   1277         return local_iterator(nullptr, __n, bucket_count());
   1278 #endif
   1279     }
   1280 
   1281     _LIBCPP_INLINE_VISIBILITY
   1282     const_local_iterator
   1283     cbegin(size_type __n) const
   1284     {
   1285         _LIBCPP_ASSERT(__n < bucket_count(),
   1286             "unordered container::cbegin(n) called with n >= bucket_count()");
   1287 #if _LIBCPP_DEBUG_LEVEL >= 2
   1288         return const_local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
   1289 #else
   1290         return const_local_iterator(__bucket_list_[__n], __n, bucket_count());
   1291 #endif
   1292     }
   1293 
   1294     _LIBCPP_INLINE_VISIBILITY
   1295     const_local_iterator
   1296     cend(size_type __n) const
   1297     {
   1298         _LIBCPP_ASSERT(__n < bucket_count(),
   1299             "unordered container::cend(n) called with n >= bucket_count()");
   1300 #if _LIBCPP_DEBUG_LEVEL >= 2
   1301         return const_local_iterator(nullptr, __n, bucket_count(), this);
   1302 #else
   1303         return const_local_iterator(nullptr, __n, bucket_count());
   1304 #endif
   1305     }
   1306 
   1307 #if _LIBCPP_DEBUG_LEVEL >= 2
   1308 
   1309     bool __dereferenceable(const const_iterator* __i) const;
   1310     bool __decrementable(const const_iterator* __i) const;
   1311     bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
   1312     bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
   1313 
   1314 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
   1315 
   1316 private:
   1317     void __rehash(size_type __n);
   1318 
   1319 #ifndef _LIBCPP_CXX03_LANG
   1320     template <class ..._Args>
   1321     __node_holder __construct_node(_Args&& ...__args);
   1322 
   1323     template <class _First, class ..._Rest>
   1324     __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
   1325 #else // _LIBCPP_CXX03_LANG
   1326     __node_holder __construct_node(const __container_value_type& __v);
   1327     __node_holder __construct_node_hash(size_t __hash, const __container_value_type& __v);
   1328 #endif
   1329 
   1330 
   1331     _LIBCPP_INLINE_VISIBILITY
   1332     void __copy_assign_alloc(const __hash_table& __u)
   1333         {__copy_assign_alloc(__u, integral_constant<bool,
   1334              __node_traits::propagate_on_container_copy_assignment::value>());}
   1335     void __copy_assign_alloc(const __hash_table& __u, true_type);
   1336     _LIBCPP_INLINE_VISIBILITY
   1337         void __copy_assign_alloc(const __hash_table&, false_type) {}
   1338 
   1339 #ifndef _LIBCPP_CXX03_LANG
   1340     void __move_assign(__hash_table& __u, false_type);
   1341     void __move_assign(__hash_table& __u, true_type)
   1342         _NOEXCEPT_(
   1343             is_nothrow_move_assignable<__node_allocator>::value &&
   1344             is_nothrow_move_assignable<hasher>::value &&
   1345             is_nothrow_move_assignable<key_equal>::value);
   1346     _LIBCPP_INLINE_VISIBILITY
   1347     void __move_assign_alloc(__hash_table& __u)
   1348         _NOEXCEPT_(
   1349             !__node_traits::propagate_on_container_move_assignment::value ||
   1350             (is_nothrow_move_assignable<__pointer_allocator>::value &&
   1351              is_nothrow_move_assignable<__node_allocator>::value))
   1352         {__move_assign_alloc(__u, integral_constant<bool,
   1353              __node_traits::propagate_on_container_move_assignment::value>());}
   1354     _LIBCPP_INLINE_VISIBILITY
   1355     void __move_assign_alloc(__hash_table& __u, true_type)
   1356         _NOEXCEPT_(
   1357             is_nothrow_move_assignable<__pointer_allocator>::value &&
   1358             is_nothrow_move_assignable<__node_allocator>::value)
   1359     {
   1360         __bucket_list_.get_deleter().__alloc() =
   1361                 _VSTD::move(__u.__bucket_list_.get_deleter().__alloc());
   1362         __node_alloc() = _VSTD::move(__u.__node_alloc());
   1363     }
   1364     _LIBCPP_INLINE_VISIBILITY
   1365         void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
   1366 #endif // _LIBCPP_CXX03_LANG
   1367 
   1368     void __deallocate_node(__next_pointer __np) _NOEXCEPT;
   1369     __next_pointer __detach() _NOEXCEPT;
   1370 
   1371     template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
   1372     template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
   1373 };
   1374 
   1375 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1376 inline
   1377 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table()
   1378     _NOEXCEPT_(
   1379         is_nothrow_default_constructible<__bucket_list>::value &&
   1380         is_nothrow_default_constructible<__first_node>::value &&
   1381         is_nothrow_default_constructible<__node_allocator>::value &&
   1382         is_nothrow_default_constructible<hasher>::value &&
   1383         is_nothrow_default_constructible<key_equal>::value)
   1384     : __p2_(0),
   1385       __p3_(1.0f)
   1386 {
   1387 }
   1388 
   1389 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1390 inline
   1391 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
   1392                                                        const key_equal& __eql)
   1393     : __bucket_list_(nullptr, __bucket_list_deleter()),
   1394       __p1_(),
   1395       __p2_(0, __hf),
   1396       __p3_(1.0f, __eql)
   1397 {
   1398 }
   1399 
   1400 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1401 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
   1402                                                        const key_equal& __eql,
   1403                                                        const allocator_type& __a)
   1404     : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
   1405       __p1_(__node_allocator(__a)),
   1406       __p2_(0, __hf),
   1407       __p3_(1.0f, __eql)
   1408 {
   1409 }
   1410 
   1411 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1412 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
   1413     : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
   1414       __p1_(__node_allocator(__a)),
   1415       __p2_(0),
   1416       __p3_(1.0f)
   1417 {
   1418 }
   1419 
   1420 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1421 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
   1422     : __bucket_list_(nullptr,
   1423           __bucket_list_deleter(allocator_traits<__pointer_allocator>::
   1424               select_on_container_copy_construction(
   1425                   __u.__bucket_list_.get_deleter().__alloc()), 0)),
   1426       __p1_(allocator_traits<__node_allocator>::
   1427           select_on_container_copy_construction(__u.__node_alloc())),
   1428       __p2_(0, __u.hash_function()),
   1429       __p3_(__u.__p3_)
   1430 {
   1431 }
   1432 
   1433 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1434 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
   1435                                                        const allocator_type& __a)
   1436     : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
   1437       __p1_(__node_allocator(__a)),
   1438       __p2_(0, __u.hash_function()),
   1439       __p3_(__u.__p3_)
   1440 {
   1441 }
   1442 
   1443 #ifndef _LIBCPP_CXX03_LANG
   1444 
   1445 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1446 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
   1447         _NOEXCEPT_(
   1448             is_nothrow_move_constructible<__bucket_list>::value &&
   1449             is_nothrow_move_constructible<__first_node>::value &&
   1450             is_nothrow_move_constructible<__node_allocator>::value &&
   1451             is_nothrow_move_constructible<hasher>::value &&
   1452             is_nothrow_move_constructible<key_equal>::value)
   1453     : __bucket_list_(_VSTD::move(__u.__bucket_list_)),
   1454       __p1_(_VSTD::move(__u.__p1_)),
   1455       __p2_(_VSTD::move(__u.__p2_)),
   1456       __p3_(_VSTD::move(__u.__p3_))
   1457 {
   1458     if (size() > 0)
   1459     {
   1460         __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
   1461             __p1_.first().__ptr();
   1462         __u.__p1_.first().__next_ = nullptr;
   1463         __u.size() = 0;
   1464     }
   1465 }
   1466 
   1467 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1468 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
   1469                                                        const allocator_type& __a)
   1470     : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
   1471       __p1_(__node_allocator(__a)),
   1472       __p2_(0, _VSTD::move(__u.hash_function())),
   1473       __p3_(_VSTD::move(__u.__p3_))
   1474 {
   1475     if (__a == allocator_type(__u.__node_alloc()))
   1476     {
   1477         __bucket_list_.reset(__u.__bucket_list_.release());
   1478         __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
   1479         __u.__bucket_list_.get_deleter().size() = 0;
   1480         if (__u.size() > 0)
   1481         {
   1482             __p1_.first().__next_ = __u.__p1_.first().__next_;
   1483             __u.__p1_.first().__next_ = nullptr;
   1484             __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
   1485                 __p1_.first().__ptr();
   1486             size() = __u.size();
   1487             __u.size() = 0;
   1488         }
   1489     }
   1490 }
   1491 
   1492 #endif  // _LIBCPP_CXX03_LANG
   1493 
   1494 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1495 __hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
   1496 {
   1497 #if defined(_LIBCPP_CXX03_LANG)
   1498     static_assert((is_copy_constructible<key_equal>::value),
   1499                  "Predicate must be copy-constructible.");
   1500     static_assert((is_copy_constructible<hasher>::value),
   1501                  "Hasher must be copy-constructible.");
   1502 #endif
   1503 
   1504     __deallocate_node(__p1_.first().__next_);
   1505 #if _LIBCPP_DEBUG_LEVEL >= 2
   1506     __get_db()->__erase_c(this);
   1507 #endif
   1508 }
   1509 
   1510 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1511 void
   1512 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(
   1513         const __hash_table& __u, true_type)
   1514 {
   1515     if (__node_alloc() != __u.__node_alloc())
   1516     {
   1517         clear();
   1518         __bucket_list_.reset();
   1519         __bucket_list_.get_deleter().size() = 0;
   1520     }
   1521     __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
   1522     __node_alloc() = __u.__node_alloc();
   1523 }
   1524 
   1525 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1526 __hash_table<_Tp, _Hash, _Equal, _Alloc>&
   1527 __hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u)
   1528 {
   1529     if (this != &__u)
   1530     {
   1531         __copy_assign_alloc(__u);
   1532         hash_function() = __u.hash_function();
   1533         key_eq() = __u.key_eq();
   1534         max_load_factor() = __u.max_load_factor();
   1535         __assign_multi(__u.begin(), __u.end());
   1536     }
   1537     return *this;
   1538 }
   1539 
   1540 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1541 void
   1542 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np)
   1543     _NOEXCEPT
   1544 {
   1545     __node_allocator& __na = __node_alloc();
   1546     while (__np != nullptr)
   1547     {
   1548         __next_pointer __next = __np->__next_;
   1549 #if _LIBCPP_DEBUG_LEVEL >= 2
   1550         __c_node* __c = __get_db()->__find_c_and_lock(this);
   1551         for (__i_node** __p = __c->end_; __p != __c->beg_; )
   1552         {
   1553             --__p;
   1554             iterator* __i = static_cast<iterator*>((*__p)->__i_);
   1555             if (__i->__node_ == __np)
   1556             {
   1557                 (*__p)->__c_ = nullptr;
   1558                 if (--__c->end_ != __p)
   1559                     memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
   1560             }
   1561         }
   1562         __get_db()->unlock();
   1563 #endif
   1564         __node_pointer __real_np = __np->__upcast();
   1565         __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__value_));
   1566         __node_traits::deallocate(__na, __real_np, 1);
   1567         __np = __next;
   1568     }
   1569 }
   1570 
   1571 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1572 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
   1573 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
   1574 {
   1575     size_type __bc = bucket_count();
   1576     for (size_type __i = 0; __i < __bc; ++__i)
   1577         __bucket_list_[__i] = nullptr;
   1578     size() = 0;
   1579     __next_pointer __cache = __p1_.first().__next_;
   1580     __p1_.first().__next_ = nullptr;
   1581     return __cache;
   1582 }
   1583 
   1584 #ifndef _LIBCPP_CXX03_LANG
   1585 
   1586 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1587 void
   1588 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
   1589         __hash_table& __u, true_type)
   1590     _NOEXCEPT_(
   1591         is_nothrow_move_assignable<__node_allocator>::value &&
   1592         is_nothrow_move_assignable<hasher>::value &&
   1593         is_nothrow_move_assignable<key_equal>::value)
   1594 {
   1595     clear();
   1596     __bucket_list_.reset(__u.__bucket_list_.release());
   1597     __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
   1598     __u.__bucket_list_.get_deleter().size() = 0;
   1599     __move_assign_alloc(__u);
   1600     size() = __u.size();
   1601     hash_function() = _VSTD::move(__u.hash_function());
   1602     max_load_factor() = __u.max_load_factor();
   1603     key_eq() = _VSTD::move(__u.key_eq());
   1604     __p1_.first().__next_ = __u.__p1_.first().__next_;
   1605     if (size() > 0)
   1606     {
   1607         __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
   1608             __p1_.first().__ptr();
   1609         __u.__p1_.first().__next_ = nullptr;
   1610         __u.size() = 0;
   1611     }
   1612 #if _LIBCPP_DEBUG_LEVEL >= 2
   1613     __get_db()->swap(this, &__u);
   1614 #endif
   1615 }
   1616 
   1617 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1618 void
   1619 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
   1620         __hash_table& __u, false_type)
   1621 {
   1622     if (__node_alloc() == __u.__node_alloc())
   1623         __move_assign(__u, true_type());
   1624     else
   1625     {
   1626         hash_function() = _VSTD::move(__u.hash_function());
   1627         key_eq() = _VSTD::move(__u.key_eq());
   1628         max_load_factor() = __u.max_load_factor();
   1629         if (bucket_count() != 0)
   1630         {
   1631             __next_pointer __cache = __detach();
   1632 #ifndef _LIBCPP_NO_EXCEPTIONS
   1633             try
   1634             {
   1635 #endif  // _LIBCPP_NO_EXCEPTIONS
   1636                 const_iterator __i = __u.begin();
   1637                 while (__cache != nullptr && __u.size() != 0)
   1638                 {
   1639                     __cache->__upcast()->__value_ =
   1640                         _VSTD::move(__u.remove(__i++)->__value_);
   1641                     __next_pointer __next = __cache->__next_;
   1642                     __node_insert_multi(__cache->__upcast());
   1643                     __cache = __next;
   1644                 }
   1645 #ifndef _LIBCPP_NO_EXCEPTIONS
   1646             }
   1647             catch (...)
   1648             {
   1649                 __deallocate_node(__cache);
   1650                 throw;
   1651             }
   1652 #endif  // _LIBCPP_NO_EXCEPTIONS
   1653             __deallocate_node(__cache);
   1654         }
   1655         const_iterator __i = __u.begin();
   1656         while (__u.size() != 0)
   1657         {
   1658             __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__value_));
   1659             __node_insert_multi(__h.get());
   1660             __h.release();
   1661         }
   1662     }
   1663 }
   1664 
   1665 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1666 inline
   1667 __hash_table<_Tp, _Hash, _Equal, _Alloc>&
   1668 __hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
   1669     _NOEXCEPT_(
   1670         __node_traits::propagate_on_container_move_assignment::value &&
   1671         is_nothrow_move_assignable<__node_allocator>::value &&
   1672         is_nothrow_move_assignable<hasher>::value &&
   1673         is_nothrow_move_assignable<key_equal>::value)
   1674 {
   1675     __move_assign(__u, integral_constant<bool,
   1676                   __node_traits::propagate_on_container_move_assignment::value>());
   1677     return *this;
   1678 }
   1679 
   1680 #endif  // _LIBCPP_CXX03_LANG
   1681 
   1682 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1683 template <class _InputIterator>
   1684 void
   1685 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first,
   1686                                                           _InputIterator __last)
   1687 {
   1688     typedef iterator_traits<_InputIterator> _ITraits;
   1689     typedef typename _ITraits::value_type _ItValueType;
   1690     static_assert((is_same<_ItValueType, __container_value_type>::value),
   1691                   "__assign_unique may only be called with the containers value type");
   1692 
   1693     if (bucket_count() != 0)
   1694     {
   1695         __next_pointer __cache = __detach();
   1696 #ifndef _LIBCPP_NO_EXCEPTIONS
   1697         try
   1698         {
   1699 #endif  // _LIBCPP_NO_EXCEPTIONS
   1700             for (; __cache != nullptr && __first != __last; ++__first)
   1701             {
   1702                 __cache->__upcast()->__value_ = *__first;
   1703                 __next_pointer __next = __cache->__next_;
   1704                 __node_insert_unique(__cache->__upcast());
   1705                 __cache = __next;
   1706             }
   1707 #ifndef _LIBCPP_NO_EXCEPTIONS
   1708         }
   1709         catch (...)
   1710         {
   1711             __deallocate_node(__cache);
   1712             throw;
   1713         }
   1714 #endif  // _LIBCPP_NO_EXCEPTIONS
   1715         __deallocate_node(__cache);
   1716     }
   1717     for (; __first != __last; ++__first)
   1718         __insert_unique(*__first);
   1719 }
   1720 
   1721 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1722 template <class _InputIterator>
   1723 void
   1724 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first,
   1725                                                          _InputIterator __last)
   1726 {
   1727     typedef iterator_traits<_InputIterator> _ITraits;
   1728     typedef typename _ITraits::value_type _ItValueType;
   1729     static_assert((is_same<_ItValueType, __container_value_type>::value ||
   1730                   is_same<_ItValueType, __node_value_type>::value),
   1731                   "__assign_multi may only be called with the containers value type"
   1732                   " or the nodes value type");
   1733     if (bucket_count() != 0)
   1734     {
   1735         __next_pointer __cache = __detach();
   1736 #ifndef _LIBCPP_NO_EXCEPTIONS
   1737         try
   1738         {
   1739 #endif  // _LIBCPP_NO_EXCEPTIONS
   1740             for (; __cache != nullptr && __first != __last; ++__first)
   1741             {
   1742                 __cache->__upcast()->__value_ = *__first;
   1743                 __next_pointer __next = __cache->__next_;
   1744                 __node_insert_multi(__cache->__upcast());
   1745                 __cache = __next;
   1746             }
   1747 #ifndef _LIBCPP_NO_EXCEPTIONS
   1748         }
   1749         catch (...)
   1750         {
   1751             __deallocate_node(__cache);
   1752             throw;
   1753         }
   1754 #endif  // _LIBCPP_NO_EXCEPTIONS
   1755         __deallocate_node(__cache);
   1756     }
   1757     for (; __first != __last; ++__first)
   1758         __insert_multi(_NodeTypes::__get_value(*__first));
   1759 }
   1760 
   1761 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1762 inline
   1763 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   1764 __hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT
   1765 {
   1766 #if _LIBCPP_DEBUG_LEVEL >= 2
   1767     return iterator(__p1_.first().__next_, this);
   1768 #else
   1769     return iterator(__p1_.first().__next_);
   1770 #endif
   1771 }
   1772 
   1773 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1774 inline
   1775 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   1776 __hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT
   1777 {
   1778 #if _LIBCPP_DEBUG_LEVEL >= 2
   1779     return iterator(nullptr, this);
   1780 #else
   1781     return iterator(nullptr);
   1782 #endif
   1783 }
   1784 
   1785 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1786 inline
   1787 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
   1788 __hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT
   1789 {
   1790 #if _LIBCPP_DEBUG_LEVEL >= 2
   1791     return const_iterator(__p1_.first().__next_, this);
   1792 #else
   1793     return const_iterator(__p1_.first().__next_);
   1794 #endif
   1795 }
   1796 
   1797 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1798 inline
   1799 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
   1800 __hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT
   1801 {
   1802 #if _LIBCPP_DEBUG_LEVEL >= 2
   1803     return const_iterator(nullptr, this);
   1804 #else
   1805     return const_iterator(nullptr);
   1806 #endif
   1807 }
   1808 
   1809 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1810 void
   1811 __hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT
   1812 {
   1813     if (size() > 0)
   1814     {
   1815         __deallocate_node(__p1_.first().__next_);
   1816         __p1_.first().__next_ = nullptr;
   1817         size_type __bc = bucket_count();
   1818         for (size_type __i = 0; __i < __bc; ++__i)
   1819             __bucket_list_[__i] = nullptr;
   1820         size() = 0;
   1821     }
   1822 }
   1823 
   1824 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1825 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
   1826 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd)
   1827 {
   1828     __nd->__hash_ = hash_function()(__nd->__value_);
   1829     size_type __bc = bucket_count();
   1830     bool __inserted = false;
   1831     __next_pointer __ndptr;
   1832     size_t __chash;
   1833     if (__bc != 0)
   1834     {
   1835         __chash = __constrain_hash(__nd->__hash_, __bc);
   1836         __ndptr = __bucket_list_[__chash];
   1837         if (__ndptr != nullptr)
   1838         {
   1839             for (__ndptr = __ndptr->__next_; __ndptr != nullptr &&
   1840                                              __constrain_hash(__ndptr->__hash(), __bc) == __chash;
   1841                                                      __ndptr = __ndptr->__next_)
   1842             {
   1843                 if (key_eq()(__ndptr->__upcast()->__value_, __nd->__value_))
   1844                     goto __done;
   1845             }
   1846         }
   1847     }
   1848     {
   1849         if (size()+1 > __bc * max_load_factor() || __bc == 0)
   1850         {
   1851             rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
   1852                            size_type(ceil(float(size() + 1) / max_load_factor()))));
   1853             __bc = bucket_count();
   1854             __chash = __constrain_hash(__nd->__hash_, __bc);
   1855         }
   1856         // insert_after __bucket_list_[__chash], or __first_node if bucket is null
   1857         __next_pointer __pn = __bucket_list_[__chash];
   1858         if (__pn == nullptr)
   1859         {
   1860             __pn =__p1_.first().__ptr();
   1861             __nd->__next_ = __pn->__next_;
   1862             __pn->__next_ = __nd->__ptr();
   1863             // fix up __bucket_list_
   1864             __bucket_list_[__chash] = __pn;
   1865             if (__nd->__next_ != nullptr)
   1866                 __bucket_list_[__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
   1867         }
   1868         else
   1869         {
   1870             __nd->__next_ = __pn->__next_;
   1871             __pn->__next_ = __nd->__ptr();
   1872         }
   1873         __ndptr = __nd->__ptr();
   1874         // increment size
   1875         ++size();
   1876         __inserted = true;
   1877     }
   1878 __done:
   1879 #if _LIBCPP_DEBUG_LEVEL >= 2
   1880     return pair<iterator, bool>(iterator(__ndptr, this), __inserted);
   1881 #else
   1882     return pair<iterator, bool>(iterator(__ndptr), __inserted);
   1883 #endif
   1884 }
   1885 
   1886 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1887 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   1888 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp)
   1889 {
   1890     __cp->__hash_ = hash_function()(__cp->__value_);
   1891     size_type __bc = bucket_count();
   1892     if (size()+1 > __bc * max_load_factor() || __bc == 0)
   1893     {
   1894         rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
   1895                        size_type(ceil(float(size() + 1) / max_load_factor()))));
   1896         __bc = bucket_count();
   1897     }
   1898     size_t __chash = __constrain_hash(__cp->__hash_, __bc);
   1899     __next_pointer __pn = __bucket_list_[__chash];
   1900     if (__pn == nullptr)
   1901     {
   1902         __pn =__p1_.first().__ptr();
   1903         __cp->__next_ = __pn->__next_;
   1904         __pn->__next_ = __cp->__ptr();
   1905         // fix up __bucket_list_
   1906         __bucket_list_[__chash] = __pn;
   1907         if (__cp->__next_ != nullptr)
   1908             __bucket_list_[__constrain_hash(__cp->__next_->__hash(), __bc)]
   1909                 = __cp->__ptr();
   1910     }
   1911     else
   1912     {
   1913         for (bool __found = false; __pn->__next_ != nullptr &&
   1914                                    __constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
   1915                                                            __pn = __pn->__next_)
   1916         {
   1917             //      __found    key_eq()     action
   1918             //      false       false       loop
   1919             //      true        true        loop
   1920             //      false       true        set __found to true
   1921             //      true        false       break
   1922             if (__found != (__pn->__next_->__hash() == __cp->__hash_ &&
   1923                             key_eq()(__pn->__next_->__upcast()->__value_, __cp->__value_)))
   1924             {
   1925                 if (!__found)
   1926                     __found = true;
   1927                 else
   1928                     break;
   1929             }
   1930         }
   1931         __cp->__next_ = __pn->__next_;
   1932         __pn->__next_ = __cp->__ptr();
   1933         if (__cp->__next_ != nullptr)
   1934         {
   1935             size_t __nhash = __constrain_hash(__cp->__next_->__hash(), __bc);
   1936             if (__nhash != __chash)
   1937                 __bucket_list_[__nhash] = __cp->__ptr();
   1938         }
   1939     }
   1940     ++size();
   1941 #if _LIBCPP_DEBUG_LEVEL >= 2
   1942     return iterator(__cp->__ptr(), this);
   1943 #else
   1944     return iterator(__cp->__ptr());
   1945 #endif
   1946 }
   1947 
   1948 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1949 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   1950 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
   1951         const_iterator __p, __node_pointer __cp)
   1952 {
   1953 #if _LIBCPP_DEBUG_LEVEL >= 2
   1954     _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
   1955         "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
   1956         " referring to this unordered container");
   1957 #endif
   1958     if (__p != end() && key_eq()(*__p, __cp->__value_))
   1959     {
   1960         __next_pointer __np = __p.__node_;
   1961         __cp->__hash_ = __np->__hash();
   1962         size_type __bc = bucket_count();
   1963         if (size()+1 > __bc * max_load_factor() || __bc == 0)
   1964         {
   1965             rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
   1966                            size_type(ceil(float(size() + 1) / max_load_factor()))));
   1967             __bc = bucket_count();
   1968         }
   1969         size_t __chash = __constrain_hash(__cp->__hash_, __bc);
   1970         __next_pointer __pp = __bucket_list_[__chash];
   1971         while (__pp->__next_ != __np)
   1972             __pp = __pp->__next_;
   1973         __cp->__next_ = __np;
   1974         __pp->__next_ = static_cast<__next_pointer>(__cp);
   1975         ++size();
   1976 #if _LIBCPP_DEBUG_LEVEL >= 2
   1977         return iterator(static_cast<__next_pointer>(__cp), this);
   1978 #else
   1979         return iterator(static_cast<__next_pointer>(__cp));
   1980 #endif
   1981     }
   1982     return __node_insert_multi(__cp);
   1983 }
   1984 
   1985 
   1986 
   1987 #ifndef _LIBCPP_CXX03_LANG
   1988 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1989 template <class _Key, class ..._Args>
   1990 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
   1991 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
   1992 #else
   1993 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   1994 template <class _Key, class _Args>
   1995 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
   1996 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args& __args)
   1997 #endif
   1998 {
   1999 
   2000     size_t __hash = hash_function()(__k);
   2001     size_type __bc = bucket_count();
   2002     bool __inserted = false;
   2003     __next_pointer __nd;
   2004     size_t __chash;
   2005     if (__bc != 0)
   2006     {
   2007         __chash = __constrain_hash(__hash, __bc);
   2008         __nd = __bucket_list_[__chash];
   2009         if (__nd != nullptr)
   2010         {
   2011             for (__nd = __nd->__next_; __nd != nullptr &&
   2012                 (__nd->__hash() == __hash || __constrain_hash(__nd->__hash(), __bc) == __chash);
   2013                                                            __nd = __nd->__next_)
   2014             {
   2015                 if (key_eq()(__nd->__upcast()->__value_, __k))
   2016                     goto __done;
   2017             }
   2018         }
   2019     }
   2020     {
   2021 #ifndef _LIBCPP_CXX03_LANG
   2022         __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
   2023 #else
   2024         __node_holder __h = __construct_node_hash(__hash, __args);
   2025 #endif
   2026         if (size()+1 > __bc * max_load_factor() || __bc == 0)
   2027         {
   2028             rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
   2029                            size_type(ceil(float(size() + 1) / max_load_factor()))));
   2030             __bc = bucket_count();
   2031             __chash = __constrain_hash(__hash, __bc);
   2032         }
   2033         // insert_after __bucket_list_[__chash], or __first_node if bucket is null
   2034         __next_pointer __pn = __bucket_list_[__chash];
   2035         if (__pn == nullptr)
   2036         {
   2037             __pn = __p1_.first().__ptr();
   2038             __h->__next_ = __pn->__next_;
   2039             __pn->__next_ = __h.get()->__ptr();
   2040             // fix up __bucket_list_
   2041             __bucket_list_[__chash] = __pn;
   2042             if (__h->__next_ != nullptr)
   2043                 __bucket_list_[__constrain_hash(__h->__next_->__hash(), __bc)]
   2044                     = __h.get()->__ptr();
   2045         }
   2046         else
   2047         {
   2048             __h->__next_ = __pn->__next_;
   2049             __pn->__next_ = static_cast<__next_pointer>(__h.get());
   2050         }
   2051         __nd = static_cast<__next_pointer>(__h.release());
   2052         // increment size
   2053         ++size();
   2054         __inserted = true;
   2055     }
   2056 __done:
   2057 #if _LIBCPP_DEBUG_LEVEL >= 2
   2058     return pair<iterator, bool>(iterator(__nd, this), __inserted);
   2059 #else
   2060     return pair<iterator, bool>(iterator(__nd), __inserted);
   2061 #endif
   2062 }
   2063 
   2064 #ifndef _LIBCPP_CXX03_LANG
   2065 
   2066 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2067 template <class... _Args>
   2068 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
   2069 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args)
   2070 {
   2071     __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
   2072     pair<iterator, bool> __r = __node_insert_unique(__h.get());
   2073     if (__r.second)
   2074         __h.release();
   2075     return __r;
   2076 }
   2077 
   2078 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2079 template <class... _Args>
   2080 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2081 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args)
   2082 {
   2083     __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
   2084     iterator __r = __node_insert_multi(__h.get());
   2085     __h.release();
   2086     return __r;
   2087 }
   2088 
   2089 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2090 template <class... _Args>
   2091 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2092 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
   2093         const_iterator __p, _Args&&... __args)
   2094 {
   2095 #if _LIBCPP_DEBUG_LEVEL >= 2
   2096     _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
   2097         "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
   2098         " referring to this unordered container");
   2099 #endif
   2100     __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
   2101     iterator __r = __node_insert_multi(__p, __h.get());
   2102     __h.release();
   2103     return __r;
   2104 }
   2105 
   2106 #else // _LIBCPP_CXX03_LANG
   2107 
   2108 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2109 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2110 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const __container_value_type& __x)
   2111 {
   2112     __node_holder __h = __construct_node(__x);
   2113     iterator __r = __node_insert_multi(__h.get());
   2114     __h.release();
   2115     return __r;
   2116 }
   2117 
   2118 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2119 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2120 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const_iterator __p,
   2121                                                          const __container_value_type& __x)
   2122 {
   2123 #if _LIBCPP_DEBUG_LEVEL >= 2
   2124     _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
   2125         "unordered container::insert(const_iterator, lvalue) called with an iterator not"
   2126         " referring to this unordered container");
   2127 #endif
   2128     __node_holder __h = __construct_node(__x);
   2129     iterator __r = __node_insert_multi(__p, __h.get());
   2130     __h.release();
   2131     return __r;
   2132 }
   2133 
   2134 #endif  // _LIBCPP_CXX03_LANG
   2135 
   2136 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2137 void
   2138 __hash_table<_Tp, _Hash, _Equal, _Alloc>::rehash(size_type __n)
   2139 {
   2140     if (__n == 1)
   2141         __n = 2;
   2142     else if (__n & (__n - 1))
   2143         __n = __next_prime(__n);
   2144     size_type __bc = bucket_count();
   2145     if (__n > __bc)
   2146         __rehash(__n);
   2147     else if (__n < __bc)
   2148     {
   2149         __n = _VSTD::max<size_type>
   2150               (
   2151                   __n,
   2152                   __is_hash_power2(__bc) ? __next_hash_pow2(size_t(ceil(float(size()) / max_load_factor()))) :
   2153                                            __next_prime(size_t(ceil(float(size()) / max_load_factor())))
   2154               );
   2155         if (__n < __bc)
   2156             __rehash(__n);
   2157     }
   2158 }
   2159 
   2160 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2161 void
   2162 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __nbc)
   2163 {
   2164 #if _LIBCPP_DEBUG_LEVEL >= 2
   2165     __get_db()->__invalidate_all(this);
   2166 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
   2167     __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
   2168     __bucket_list_.reset(__nbc > 0 ?
   2169                       __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
   2170     __bucket_list_.get_deleter().size() = __nbc;
   2171     if (__nbc > 0)
   2172     {
   2173         for (size_type __i = 0; __i < __nbc; ++__i)
   2174             __bucket_list_[__i] = nullptr;
   2175         __next_pointer __pp = __p1_.first().__ptr();
   2176         __next_pointer __cp = __pp->__next_;
   2177         if (__cp != nullptr)
   2178         {
   2179             size_type __chash = __constrain_hash(__cp->__hash(), __nbc);
   2180             __bucket_list_[__chash] = __pp;
   2181             size_type __phash = __chash;
   2182             for (__pp = __cp, __cp = __cp->__next_; __cp != nullptr;
   2183                                                            __cp = __pp->__next_)
   2184             {
   2185                 __chash = __constrain_hash(__cp->__hash(), __nbc);
   2186                 if (__chash == __phash)
   2187                     __pp = __cp;
   2188                 else
   2189                 {
   2190                     if (__bucket_list_[__chash] == nullptr)
   2191                     {
   2192                         __bucket_list_[__chash] = __pp;
   2193                         __pp = __cp;
   2194                         __phash = __chash;
   2195                     }
   2196                     else
   2197                     {
   2198                         __next_pointer __np = __cp;
   2199                         for (; __np->__next_ != nullptr &&
   2200                                key_eq()(__cp->__upcast()->__value_,
   2201                                         __np->__next_->__upcast()->__value_);
   2202                                                            __np = __np->__next_)
   2203                             ;
   2204                         __pp->__next_ = __np->__next_;
   2205                         __np->__next_ = __bucket_list_[__chash]->__next_;
   2206                         __bucket_list_[__chash]->__next_ = __cp;
   2207 
   2208                     }
   2209                 }
   2210             }
   2211         }
   2212     }
   2213 }
   2214 
   2215 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2216 template <class _Key>
   2217 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2218 __hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k)
   2219 {
   2220     size_t __hash = hash_function()(__k);
   2221     size_type __bc = bucket_count();
   2222     if (__bc != 0)
   2223     {
   2224         size_t __chash = __constrain_hash(__hash, __bc);
   2225         __next_pointer __nd = __bucket_list_[__chash];
   2226         if (__nd != nullptr)
   2227         {
   2228             for (__nd = __nd->__next_; __nd != nullptr &&
   2229                 (__nd->__hash() == __hash
   2230                   || __constrain_hash(__nd->__hash(), __bc) == __chash);
   2231                                                            __nd = __nd->__next_)
   2232             {
   2233                 if ((__nd->__hash() == __hash)
   2234                     && key_eq()(__nd->__upcast()->__value_, __k))
   2235 #if _LIBCPP_DEBUG_LEVEL >= 2
   2236                     return iterator(__nd, this);
   2237 #else
   2238                     return iterator(__nd);
   2239 #endif
   2240             }
   2241         }
   2242     }
   2243     return end();
   2244 }
   2245 
   2246 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2247 template <class _Key>
   2248 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
   2249 __hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
   2250 {
   2251     size_t __hash = hash_function()(__k);
   2252     size_type __bc = bucket_count();
   2253     if (__bc != 0)
   2254     {
   2255         size_t __chash = __constrain_hash(__hash, __bc);
   2256         __next_pointer __nd = __bucket_list_[__chash];
   2257         if (__nd != nullptr)
   2258         {
   2259             for (__nd = __nd->__next_; __nd != nullptr &&
   2260                 (__hash == __nd->__hash()
   2261                     || __constrain_hash(__nd->__hash(), __bc) == __chash);
   2262                                                            __nd = __nd->__next_)
   2263             {
   2264                 if ((__nd->__hash() == __hash)
   2265                     && key_eq()(__nd->__upcast()->__value_, __k))
   2266 #if _LIBCPP_DEBUG_LEVEL >= 2
   2267                     return const_iterator(__nd, this);
   2268 #else
   2269                     return const_iterator(__nd);
   2270 #endif
   2271             }
   2272         }
   2273 
   2274     }
   2275     return end();
   2276 }
   2277 
   2278 #ifndef _LIBCPP_CXX03_LANG
   2279 
   2280 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2281 template <class ..._Args>
   2282 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
   2283 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&& ...__args)
   2284 {
   2285     static_assert(!__is_hash_value_type<_Args...>::value,
   2286                   "Construct cannot be called with a hash value type");
   2287     __node_allocator& __na = __node_alloc();
   2288     __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
   2289     __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
   2290     __h.get_deleter().__value_constructed = true;
   2291     __h->__hash_ = hash_function()(__h->__value_);
   2292     __h->__next_ = nullptr;
   2293     return __h;
   2294 }
   2295 
   2296 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2297 template <class _First, class ..._Rest>
   2298 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
   2299 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
   2300     size_t __hash, _First&& __f, _Rest&& ...__rest)
   2301 {
   2302     static_assert(!__is_hash_value_type<_First, _Rest...>::value,
   2303                   "Construct cannot be called with a hash value type");
   2304     __node_allocator& __na = __node_alloc();
   2305     __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
   2306     __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
   2307                              _VSTD::forward<_First>(__f),
   2308                              _VSTD::forward<_Rest>(__rest)...);
   2309     __h.get_deleter().__value_constructed = true;
   2310     __h->__hash_ = __hash;
   2311     __h->__next_ = nullptr;
   2312     return __h;
   2313 }
   2314 
   2315 #else  // _LIBCPP_CXX03_LANG
   2316 
   2317 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2318 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
   2319 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(const __container_value_type& __v)
   2320 {
   2321     __node_allocator& __na = __node_alloc();
   2322     __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
   2323     __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
   2324     __h.get_deleter().__value_constructed = true;
   2325     __h->__hash_ = hash_function()(__h->__value_);
   2326     __h->__next_ = nullptr;
   2327     return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
   2328 }
   2329 
   2330 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2331 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
   2332 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(size_t __hash,
   2333                                                                 const __container_value_type& __v)
   2334 {
   2335     __node_allocator& __na = __node_alloc();
   2336     __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
   2337     __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
   2338     __h.get_deleter().__value_constructed = true;
   2339     __h->__hash_ = __hash;
   2340     __h->__next_ = nullptr;
   2341     return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
   2342 }
   2343 
   2344 #endif  // _LIBCPP_CXX03_LANG
   2345 
   2346 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2347 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2348 __hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
   2349 {
   2350     __next_pointer __np = __p.__node_;
   2351 #if _LIBCPP_DEBUG_LEVEL >= 2
   2352     _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
   2353         "unordered container erase(iterator) called with an iterator not"
   2354         " referring to this container");
   2355     _LIBCPP_ASSERT(__p != end(),
   2356         "unordered container erase(iterator) called with a non-dereferenceable iterator");
   2357     iterator __r(__np, this);
   2358 #else
   2359     iterator __r(__np);
   2360 #endif
   2361     ++__r;
   2362     remove(__p);
   2363     return __r;
   2364 }
   2365 
   2366 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2367 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
   2368 __hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first,
   2369                                                 const_iterator __last)
   2370 {
   2371 #if _LIBCPP_DEBUG_LEVEL >= 2
   2372     _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
   2373         "unodered container::erase(iterator, iterator) called with an iterator not"
   2374         " referring to this unodered container");
   2375     _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__last) == this,
   2376         "unodered container::erase(iterator, iterator) called with an iterator not"
   2377         " referring to this unodered container");
   2378 #endif
   2379     for (const_iterator __p = __first; __first != __last; __p = __first)
   2380     {
   2381         ++__first;
   2382         erase(__p);
   2383     }
   2384     __next_pointer __np = __last.__node_;
   2385 #if _LIBCPP_DEBUG_LEVEL >= 2
   2386     return iterator (__np, this);
   2387 #else
   2388     return iterator (__np);
   2389 #endif
   2390 }
   2391 
   2392 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2393 template <class _Key>
   2394 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
   2395 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k)
   2396 {
   2397     iterator __i = find(__k);
   2398     if (__i == end())
   2399         return 0;
   2400     erase(__i);
   2401     return 1;
   2402 }
   2403 
   2404 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2405 template <class _Key>
   2406 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
   2407 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k)
   2408 {
   2409     size_type __r = 0;
   2410     iterator __i = find(__k);
   2411     if (__i != end())
   2412     {
   2413         iterator __e = end();
   2414         do
   2415         {
   2416             erase(__i++);
   2417             ++__r;
   2418         } while (__i != __e && key_eq()(*__i, __k));
   2419     }
   2420     return __r;
   2421 }
   2422 
   2423 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2424 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
   2425 __hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT
   2426 {
   2427     // current node
   2428     __next_pointer __cn = __p.__node_;
   2429     size_type __bc = bucket_count();
   2430     size_t __chash = __constrain_hash(__cn->__hash(), __bc);
   2431     // find previous node
   2432     __next_pointer __pn = __bucket_list_[__chash];
   2433     for (; __pn->__next_ != __cn; __pn = __pn->__next_)
   2434         ;
   2435     // Fix up __bucket_list_
   2436         // if __pn is not in same bucket (before begin is not in same bucket) &&
   2437         //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
   2438     if (__pn == __p1_.first().__ptr()
   2439             || __constrain_hash(__pn->__hash(), __bc) != __chash)
   2440     {
   2441         if (__cn->__next_ == nullptr
   2442             || __constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
   2443             __bucket_list_[__chash] = nullptr;
   2444     }
   2445         // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
   2446     if (__cn->__next_ != nullptr)
   2447     {
   2448         size_t __nhash = __constrain_hash(__cn->__next_->__hash(), __bc);
   2449         if (__nhash != __chash)
   2450             __bucket_list_[__nhash] = __pn;
   2451     }
   2452     // remove __cn
   2453     __pn->__next_ = __cn->__next_;
   2454     __cn->__next_ = nullptr;
   2455     --size();
   2456 #if _LIBCPP_DEBUG_LEVEL >= 2
   2457     __c_node* __c = __get_db()->__find_c_and_lock(this);
   2458     for (__i_node** __dp = __c->end_; __dp != __c->beg_; )
   2459     {
   2460         --__dp;
   2461         iterator* __i = static_cast<iterator*>((*__dp)->__i_);
   2462         if (__i->__node_ == __cn)
   2463         {
   2464             (*__dp)->__c_ = nullptr;
   2465             if (--__c->end_ != __dp)
   2466                 memmove(__dp, __dp+1, (__c->end_ - __dp)*sizeof(__i_node*));
   2467         }
   2468     }
   2469     __get_db()->unlock();
   2470 #endif
   2471     return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
   2472 }
   2473 
   2474 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2475 template <class _Key>
   2476 inline
   2477 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
   2478 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const
   2479 {
   2480     return static_cast<size_type>(find(__k) != end());
   2481 }
   2482 
   2483 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2484 template <class _Key>
   2485 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
   2486 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const
   2487 {
   2488     size_type __r = 0;
   2489     const_iterator __i = find(__k);
   2490     if (__i != end())
   2491     {
   2492         const_iterator __e = end();
   2493         do
   2494         {
   2495             ++__i;
   2496             ++__r;
   2497         } while (__i != __e && key_eq()(*__i, __k));
   2498     }
   2499     return __r;
   2500 }
   2501 
   2502 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2503 template <class _Key>
   2504 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
   2505      typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
   2506 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
   2507         const _Key& __k)
   2508 {
   2509     iterator __i = find(__k);
   2510     iterator __j = __i;
   2511     if (__i != end())
   2512         ++__j;
   2513     return pair<iterator, iterator>(__i, __j);
   2514 }
   2515 
   2516 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2517 template <class _Key>
   2518 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
   2519      typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
   2520 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
   2521         const _Key& __k) const
   2522 {
   2523     const_iterator __i = find(__k);
   2524     const_iterator __j = __i;
   2525     if (__i != end())
   2526         ++__j;
   2527     return pair<const_iterator, const_iterator>(__i, __j);
   2528 }
   2529 
   2530 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2531 template <class _Key>
   2532 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
   2533      typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
   2534 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
   2535         const _Key& __k)
   2536 {
   2537     iterator __i = find(__k);
   2538     iterator __j = __i;
   2539     if (__i != end())
   2540     {
   2541         iterator __e = end();
   2542         do
   2543         {
   2544             ++__j;
   2545         } while (__j != __e && key_eq()(*__j, __k));
   2546     }
   2547     return pair<iterator, iterator>(__i, __j);
   2548 }
   2549 
   2550 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2551 template <class _Key>
   2552 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
   2553      typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
   2554 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
   2555         const _Key& __k) const
   2556 {
   2557     const_iterator __i = find(__k);
   2558     const_iterator __j = __i;
   2559     if (__i != end())
   2560     {
   2561         const_iterator __e = end();
   2562         do
   2563         {
   2564             ++__j;
   2565         } while (__j != __e && key_eq()(*__j, __k));
   2566     }
   2567     return pair<const_iterator, const_iterator>(__i, __j);
   2568 }
   2569 
   2570 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2571 void
   2572 __hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
   2573 #if _LIBCPP_STD_VER <= 11
   2574     _NOEXCEPT_DEBUG_(
   2575         __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
   2576         && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
   2577               || __is_nothrow_swappable<__pointer_allocator>::value)
   2578         && (!__node_traits::propagate_on_container_swap::value
   2579               || __is_nothrow_swappable<__node_allocator>::value)
   2580             )
   2581 #else
   2582   _NOEXCEPT_DEBUG_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value)
   2583 #endif
   2584 {
   2585     _LIBCPP_ASSERT(__node_traits::propagate_on_container_swap::value ||
   2586                    this->__node_alloc() == __u.__node_alloc(),
   2587                    "list::swap: Either propagate_on_container_swap must be true"
   2588                    " or the allocators must compare equal");
   2589     {
   2590     __node_pointer_pointer __npp = __bucket_list_.release();
   2591     __bucket_list_.reset(__u.__bucket_list_.release());
   2592     __u.__bucket_list_.reset(__npp);
   2593     }
   2594     _VSTD::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
   2595     __swap_allocator(__bucket_list_.get_deleter().__alloc(),
   2596              __u.__bucket_list_.get_deleter().__alloc());
   2597     __swap_allocator(__node_alloc(), __u.__node_alloc());
   2598     _VSTD::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
   2599     __p2_.swap(__u.__p2_);
   2600     __p3_.swap(__u.__p3_);
   2601     if (size() > 0)
   2602         __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
   2603             __p1_.first().__ptr();
   2604     if (__u.size() > 0)
   2605         __u.__bucket_list_[__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
   2606             __u.__p1_.first().__ptr();
   2607 #if _LIBCPP_DEBUG_LEVEL >= 2
   2608     __get_db()->swap(this, &__u);
   2609 #endif
   2610 }
   2611 
   2612 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2613 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
   2614 __hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const
   2615 {
   2616     _LIBCPP_ASSERT(__n < bucket_count(),
   2617         "unordered container::bucket_size(n) called with n >= bucket_count()");
   2618     __next_pointer __np = __bucket_list_[__n];
   2619     size_type __bc = bucket_count();
   2620     size_type __r = 0;
   2621     if (__np != nullptr)
   2622     {
   2623         for (__np = __np->__next_; __np != nullptr &&
   2624                                    __constrain_hash(__np->__hash(), __bc) == __n;
   2625                                                     __np = __np->__next_, ++__r)
   2626             ;
   2627     }
   2628     return __r;
   2629 }
   2630 
   2631 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2632 inline _LIBCPP_INLINE_VISIBILITY
   2633 void
   2634 swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x,
   2635      __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
   2636     _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
   2637 {
   2638     __x.swap(__y);
   2639 }
   2640 
   2641 #if _LIBCPP_DEBUG_LEVEL >= 2
   2642 
   2643 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2644 bool
   2645 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__dereferenceable(const const_iterator* __i) const
   2646 {
   2647     return __i->__node_ != nullptr;
   2648 }
   2649 
   2650 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2651 bool
   2652 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__decrementable(const const_iterator*) const
   2653 {
   2654     return false;
   2655 }
   2656 
   2657 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2658 bool
   2659 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
   2660 {
   2661     return false;
   2662 }
   2663 
   2664 template <class _Tp, class _Hash, class _Equal, class _Alloc>
   2665 bool
   2666 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
   2667 {
   2668     return false;
   2669 }
   2670 
   2671 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
   2672 _LIBCPP_END_NAMESPACE_STD
   2673 
   2674 #endif  // _LIBCPP__HASH_TABLE
   2675