| // Internal policy header for TR1 unordered_set and unordered_map -*- C++ -*- |
| |
| // Copyright (C) 2005, 2006 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 2, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING. If not, write to the Free |
| // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, |
| // USA. |
| |
| // As a special exception, you may use this file as part of a free software |
| // library without restriction. Specifically, if other files instantiate |
| // templates or use macros or inline functions from this file, or you compile |
| // this file and link it with other files to produce an executable, this |
| // file does not by itself cause the resulting executable to be covered by |
| // the GNU General Public License. This exception does not however |
| // invalidate any other reasons why the executable file might be covered by |
| // the GNU General Public License. |
| |
| /** @file tr1/hashtable_policy.h |
| * This is a TR1 C++ Library header. |
| */ |
| |
| #ifndef _TR1_HASHTABLE_POLICY_H |
| #define _TR1_HASHTABLE_POLICY_H 1 |
| |
| #include <functional> // _Identity, _Select1st |
| #include <tr1/utility> |
| #include <ext/type_traits.h> |
| |
| namespace std |
| { |
| _GLIBCXX_BEGIN_NAMESPACE(tr1) |
| namespace __detail |
| { |
| // Helper function: return distance(first, last) for forward |
| // iterators, or 0 for input iterators. |
| template<class _Iterator> |
| inline typename std::iterator_traits<_Iterator>::difference_type |
| __distance_fw(_Iterator __first, _Iterator __last, |
| std::input_iterator_tag) |
| { return 0; } |
| |
| template<class _Iterator> |
| inline typename std::iterator_traits<_Iterator>::difference_type |
| __distance_fw(_Iterator __first, _Iterator __last, |
| std::forward_iterator_tag) |
| { return std::distance(__first, __last); } |
| |
| template<class _Iterator> |
| inline typename std::iterator_traits<_Iterator>::difference_type |
| __distance_fw(_Iterator __first, _Iterator __last) |
| { |
| typedef typename std::iterator_traits<_Iterator>::iterator_category _Tag; |
| return __distance_fw(__first, __last, _Tag()); |
| } |
| |
| // XXX This is a hack. _Prime_rehash_policy's member functions, and |
| // certainly the list of primes, should be defined in a .cc file. |
| // We're temporarily putting them in a header because we don't have a |
| // place to put TR1 .cc files yet. There's no good reason for any of |
| // _Prime_rehash_policy's member functions to be inline, and there's |
| // certainly no good reason for _Primes<> to exist at all. |
| struct _LessThan |
| { |
| template<typename _Tp, typename _Up> |
| bool |
| operator()(_Tp __x, _Up __y) |
| { return __x < __y; } |
| }; |
| |
| template<int __ulongsize = sizeof(unsigned long)> |
| struct _Primes |
| { |
| static const int __n_primes = __ulongsize != 8 ? 256 : 256 + 48; |
| static const unsigned long __primes[256 + 48 + 1]; |
| }; |
| |
| template<int __ulongsize> |
| const int _Primes<__ulongsize>::__n_primes; |
| |
| template<int __ulongsize> |
| const unsigned long _Primes<__ulongsize>::__primes[256 + 48 + 1] = |
| { |
| 2ul, 3ul, 5ul, 7ul, 11ul, 13ul, 17ul, 19ul, 23ul, 29ul, 31ul, |
| 37ul, 41ul, 43ul, 47ul, 53ul, 59ul, 61ul, 67ul, 71ul, 73ul, 79ul, |
| 83ul, 89ul, 97ul, 103ul, 109ul, 113ul, 127ul, 137ul, 139ul, 149ul, |
| 157ul, 167ul, 179ul, 193ul, 199ul, 211ul, 227ul, 241ul, 257ul, |
| 277ul, 293ul, 313ul, 337ul, 359ul, 383ul, 409ul, 439ul, 467ul, |
| 503ul, 541ul, 577ul, 619ul, 661ul, 709ul, 761ul, 823ul, 887ul, |
| 953ul, 1031ul, 1109ul, 1193ul, 1289ul, 1381ul, 1493ul, 1613ul, |
| 1741ul, 1879ul, 2029ul, 2179ul, 2357ul, 2549ul, 2753ul, 2971ul, |
| 3209ul, 3469ul, 3739ul, 4027ul, 4349ul, 4703ul, 5087ul, 5503ul, |
| 5953ul, 6427ul, 6949ul, 7517ul, 8123ul, 8783ul, 9497ul, 10273ul, |
| 11113ul, 12011ul, 12983ul, 14033ul, 15173ul, 16411ul, 17749ul, |
| 19183ul, 20753ul, 22447ul, 24281ul, 26267ul, 28411ul, 30727ul, |
| 33223ul, 35933ul, 38873ul, 42043ul, 45481ul, 49201ul, 53201ul, |
| 57557ul, 62233ul, 67307ul, 72817ul, 78779ul, 85229ul, 92203ul, |
| 99733ul, 107897ul, 116731ul, 126271ul, 136607ul, 147793ul, |
| 159871ul, 172933ul, 187091ul, 202409ul, 218971ul, 236897ul, |
| 256279ul, 277261ul, 299951ul, 324503ul, 351061ul, 379787ul, |
| 410857ul, 444487ul, 480881ul, 520241ul, 562841ul, 608903ul, |
| 658753ul, 712697ul, 771049ul, 834181ul, 902483ul, 976369ul, |
| 1056323ul, 1142821ul, 1236397ul, 1337629ul, 1447153ul, 1565659ul, |
| 1693859ul, 1832561ul, 1982627ul, 2144977ul, 2320627ul, 2510653ul, |
| 2716249ul, 2938679ul, 3179303ul, 3439651ul, 3721303ul, 4026031ul, |
| 4355707ul, 4712381ul, 5098259ul, 5515729ul, 5967347ul, 6456007ul, |
| 6984629ul, 7556579ul, 8175383ul, 8844859ul, 9569143ul, 10352717ul, |
| 11200489ul, 12117689ul, 13109983ul, 14183539ul, 15345007ul, |
| 16601593ul, 17961079ul, 19431899ul, 21023161ul, 22744717ul, |
| 24607243ul, 26622317ul, 28802401ul, 31160981ul, 33712729ul, |
| 36473443ul, 39460231ul, 42691603ul, 46187573ul, 49969847ul, |
| 54061849ul, 58488943ul, 63278561ul, 68460391ul, 74066549ul, |
| 80131819ul, 86693767ul, 93793069ul, 101473717ul, 109783337ul, |
| 118773397ul, 128499677ul, 139022417ul, 150406843ul, 162723577ul, |
| 176048909ul, 190465427ul, 206062531ul, 222936881ul, 241193053ul, |
| 260944219ul, 282312799ul, 305431229ul, 330442829ul, 357502601ul, |
| 386778277ul, 418451333ul, 452718089ul, 489790921ul, 529899637ul, |
| 573292817ul, 620239453ul, 671030513ul, 725980837ul, 785430967ul, |
| 849749479ul, 919334987ul, 994618837ul, 1076067617ul, 1164186217ul, |
| 1259520799ul, 1362662261ul, 1474249943ul, 1594975441ul, |
| 1725587117ul, 1866894511ul, 2019773507ul, 2185171673ul, |
| 2364114217ul, 2557710269ul, 2767159799ul, 2993761039ul, |
| 3238918481ul, 3504151727ul, 3791104843ul, 4101556399ul, |
| 4294967291ul, |
| // Sentinel, so we don't have to test the result of lower_bound, |
| // or, on 64-bit machines, rest of the table. |
| __ulongsize != 8 ? 4294967291ul : (unsigned long)6442450933ull, |
| (unsigned long)8589934583ull, |
| (unsigned long)12884901857ull, (unsigned long)17179869143ull, |
| (unsigned long)25769803693ull, (unsigned long)34359738337ull, |
| (unsigned long)51539607367ull, (unsigned long)68719476731ull, |
| (unsigned long)103079215087ull, (unsigned long)137438953447ull, |
| (unsigned long)206158430123ull, (unsigned long)274877906899ull, |
| (unsigned long)412316860387ull, (unsigned long)549755813881ull, |
| (unsigned long)824633720731ull, (unsigned long)1099511627689ull, |
| (unsigned long)1649267441579ull, (unsigned long)2199023255531ull, |
| (unsigned long)3298534883309ull, (unsigned long)4398046511093ull, |
| (unsigned long)6597069766607ull, (unsigned long)8796093022151ull, |
| (unsigned long)13194139533241ull, (unsigned long)17592186044399ull, |
| (unsigned long)26388279066581ull, (unsigned long)35184372088777ull, |
| (unsigned long)52776558133177ull, (unsigned long)70368744177643ull, |
| (unsigned long)105553116266399ull, (unsigned long)140737488355213ull, |
| (unsigned long)211106232532861ull, (unsigned long)281474976710597ull, |
| (unsigned long)562949953421231ull, (unsigned long)1125899906842597ull, |
| (unsigned long)2251799813685119ull, (unsigned long)4503599627370449ull, |
| (unsigned long)9007199254740881ull, (unsigned long)18014398509481951ull, |
| (unsigned long)36028797018963913ull, (unsigned long)72057594037927931ull, |
| (unsigned long)144115188075855859ull, |
| (unsigned long)288230376151711717ull, |
| (unsigned long)576460752303423433ull, |
| (unsigned long)1152921504606846883ull, |
| (unsigned long)2305843009213693951ull, |
| (unsigned long)4611686018427387847ull, |
| (unsigned long)9223372036854775783ull, |
| (unsigned long)18446744073709551557ull, |
| (unsigned long)18446744073709551557ull |
| }; |
| |
| // Auxiliary types used for all instantiations of _Hashtable: nodes |
| // and iterators. |
| |
| // Nodes, used to wrap elements stored in the hash table. A policy |
| // template parameter of class template _Hashtable controls whether |
| // nodes also store a hash code. In some cases (e.g. strings) this |
| // may be a performance win. |
| template<typename _Value, bool __cache_hash_code> |
| struct _Hash_node; |
| |
| template<typename _Value> |
| struct _Hash_node<_Value, true> |
| { |
| _Value _M_v; |
| std::size_t _M_hash_code; |
| _Hash_node* _M_next; |
| }; |
| |
| template<typename _Value> |
| struct _Hash_node<_Value, false> |
| { |
| _Value _M_v; |
| _Hash_node* _M_next; |
| }; |
| |
| // Local iterators, used to iterate within a bucket but not between |
| // buckets. |
| template<typename _Value, bool __cache> |
| struct _Node_iterator_base |
| { |
| _Node_iterator_base(_Hash_node<_Value, __cache>* __p) |
| : _M_cur(__p) { } |
| |
| void |
| _M_incr() |
| { _M_cur = _M_cur->_M_next; } |
| |
| _Hash_node<_Value, __cache>* _M_cur; |
| }; |
| |
| template<typename _Value, bool __cache> |
| inline bool |
| operator==(const _Node_iterator_base<_Value, __cache>& __x, |
| const _Node_iterator_base<_Value, __cache>& __y) |
| { return __x._M_cur == __y._M_cur; } |
| |
| template<typename _Value, bool __cache> |
| inline bool |
| operator!=(const _Node_iterator_base<_Value, __cache>& __x, |
| const _Node_iterator_base<_Value, __cache>& __y) |
| { return __x._M_cur != __y._M_cur; } |
| |
| template<typename _Value, bool __constant_iterators, bool __cache> |
| struct _Node_iterator |
| : public _Node_iterator_base<_Value, __cache> |
| { |
| typedef _Value value_type; |
| typedef typename |
| __gnu_cxx::__conditional_type<__constant_iterators, |
| const _Value*, _Value*>::__type |
| pointer; |
| typedef typename |
| __gnu_cxx::__conditional_type<__constant_iterators, |
| const _Value&, _Value&>::__type |
| reference; |
| typedef std::ptrdiff_t difference_type; |
| typedef std::forward_iterator_tag iterator_category; |
| |
| _Node_iterator() |
| : _Node_iterator_base<_Value, __cache>(0) { } |
| |
| explicit |
| _Node_iterator(_Hash_node<_Value, __cache>* __p) |
| : _Node_iterator_base<_Value, __cache>(__p) { } |
| |
| reference |
| operator*() const |
| { return this->_M_cur->_M_v; } |
| |
| pointer |
| operator->() const |
| { return &this->_M_cur->_M_v; } |
| |
| _Node_iterator& |
| operator++() |
| { |
| this->_M_incr(); |
| return *this; |
| } |
| |
| _Node_iterator |
| operator++(int) |
| { |
| _Node_iterator __tmp(*this); |
| this->_M_incr(); |
| return __tmp; |
| } |
| }; |
| |
| template<typename _Value, bool __constant_iterators, bool __cache> |
| struct _Node_const_iterator |
| : public _Node_iterator_base<_Value, __cache> |
| { |
| typedef _Value value_type; |
| typedef const _Value* pointer; |
| typedef const _Value& reference; |
| typedef std::ptrdiff_t difference_type; |
| typedef std::forward_iterator_tag iterator_category; |
| |
| _Node_const_iterator() |
| : _Node_iterator_base<_Value, __cache>(0) { } |
| |
| explicit |
| _Node_const_iterator(_Hash_node<_Value, __cache>* __p) |
| : _Node_iterator_base<_Value, __cache>(__p) { } |
| |
| _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators, |
| __cache>& __x) |
| : _Node_iterator_base<_Value, __cache>(__x._M_cur) { } |
| |
| reference |
| operator*() const |
| { return this->_M_cur->_M_v; } |
| |
| pointer |
| operator->() const |
| { return &this->_M_cur->_M_v; } |
| |
| _Node_const_iterator& |
| operator++() |
| { |
| this->_M_incr(); |
| return *this; |
| } |
| |
| _Node_const_iterator |
| operator++(int) |
| { |
| _Node_const_iterator __tmp(*this); |
| this->_M_incr(); |
| return __tmp; |
| } |
| }; |
| |
| template<typename _Value, bool __cache> |
| struct _Hashtable_iterator_base |
| { |
| _Hashtable_iterator_base(_Hash_node<_Value, __cache>* __node, |
| _Hash_node<_Value, __cache>** __bucket) |
| : _M_cur_node(__node), _M_cur_bucket(__bucket) { } |
| |
| void |
| _M_incr() |
| { |
| _M_cur_node = _M_cur_node->_M_next; |
| if (!_M_cur_node) |
| _M_incr_bucket(); |
| } |
| |
| void |
| _M_incr_bucket(); |
| |
| _Hash_node<_Value, __cache>* _M_cur_node; |
| _Hash_node<_Value, __cache>** _M_cur_bucket; |
| }; |
| |
| // Global iterators, used for arbitrary iteration within a hash |
| // table. Larger and more expensive than local iterators. |
| template<typename _Value, bool __cache> |
| void |
| _Hashtable_iterator_base<_Value, __cache>:: |
| _M_incr_bucket() |
| { |
| ++_M_cur_bucket; |
| |
| // This loop requires the bucket array to have a non-null sentinel. |
| while (!*_M_cur_bucket) |
| ++_M_cur_bucket; |
| _M_cur_node = *_M_cur_bucket; |
| } |
| |
| template<typename _Value, bool __cache> |
| inline bool |
| operator==(const _Hashtable_iterator_base<_Value, __cache>& __x, |
| const _Hashtable_iterator_base<_Value, __cache>& __y) |
| { return __x._M_cur_node == __y._M_cur_node; } |
| |
| template<typename _Value, bool __cache> |
| inline bool |
| operator!=(const _Hashtable_iterator_base<_Value, __cache>& __x, |
| const _Hashtable_iterator_base<_Value, __cache>& __y) |
| { return __x._M_cur_node != __y._M_cur_node; } |
| |
| template<typename _Value, bool __constant_iterators, bool __cache> |
| struct _Hashtable_iterator |
| : public _Hashtable_iterator_base<_Value, __cache> |
| { |
| typedef _Value value_type; |
| typedef typename |
| __gnu_cxx::__conditional_type<__constant_iterators, |
| const _Value*, _Value*>::__type |
| pointer; |
| typedef typename |
| __gnu_cxx::__conditional_type<__constant_iterators, |
| const _Value&, _Value&>::__type |
| reference; |
| typedef std::ptrdiff_t difference_type; |
| typedef std::forward_iterator_tag iterator_category; |
| |
| _Hashtable_iterator() |
| : _Hashtable_iterator_base<_Value, __cache>(0, 0) { } |
| |
| _Hashtable_iterator(_Hash_node<_Value, __cache>* __p, |
| _Hash_node<_Value, __cache>** __b) |
| : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { } |
| |
| explicit |
| _Hashtable_iterator(_Hash_node<_Value, __cache>** __b) |
| : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { } |
| |
| reference |
| operator*() const |
| { return this->_M_cur_node->_M_v; } |
| |
| pointer |
| operator->() const |
| { return &this->_M_cur_node->_M_v; } |
| |
| _Hashtable_iterator& |
| operator++() |
| { |
| this->_M_incr(); |
| return *this; |
| } |
| |
| _Hashtable_iterator |
| operator++(int) |
| { |
| _Hashtable_iterator __tmp(*this); |
| this->_M_incr(); |
| return __tmp; |
| } |
| }; |
| |
| template<typename _Value, bool __constant_iterators, bool __cache> |
| struct _Hashtable_const_iterator |
| : public _Hashtable_iterator_base<_Value, __cache> |
| { |
| typedef _Value value_type; |
| typedef const _Value* pointer; |
| typedef const _Value& reference; |
| typedef std::ptrdiff_t difference_type; |
| typedef std::forward_iterator_tag iterator_category; |
| |
| _Hashtable_const_iterator() |
| : _Hashtable_iterator_base<_Value, __cache>(0, 0) { } |
| |
| _Hashtable_const_iterator(_Hash_node<_Value, __cache>* __p, |
| _Hash_node<_Value, __cache>** __b) |
| : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { } |
| |
| explicit |
| _Hashtable_const_iterator(_Hash_node<_Value, __cache>** __b) |
| : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { } |
| |
| _Hashtable_const_iterator(const _Hashtable_iterator<_Value, |
| __constant_iterators, __cache>& __x) |
| : _Hashtable_iterator_base<_Value, __cache>(__x._M_cur_node, |
| __x._M_cur_bucket) { } |
| |
| reference |
| operator*() const |
| { return this->_M_cur_node->_M_v; } |
| |
| pointer |
| operator->() const |
| { return &this->_M_cur_node->_M_v; } |
| |
| _Hashtable_const_iterator& |
| operator++() |
| { |
| this->_M_incr(); |
| return *this; |
| } |
| |
| _Hashtable_const_iterator |
| operator++(int) |
| { |
| _Hashtable_const_iterator __tmp(*this); |
| this->_M_incr(); |
| return __tmp; |
| } |
| }; |
| |
| |
| // Many of class template _Hashtable's template parameters are policy |
| // classes. These are defaults for the policies. |
| |
| // Default range hashing function: use division to fold a large number |
| // into the range [0, N). |
| struct _Mod_range_hashing |
| { |
| typedef std::size_t first_argument_type; |
| typedef std::size_t second_argument_type; |
| typedef std::size_t result_type; |
| |
| result_type |
| operator()(first_argument_type __num, second_argument_type __den) const |
| { return __num % __den; } |
| }; |
| |
| // Default ranged hash function H. In principle it should be a |
| // function object composed from objects of type H1 and H2 such that |
| // h(k, N) = h2(h1(k), N), but that would mean making extra copies of |
| // h1 and h2. So instead we'll just use a tag to tell class template |
| // hashtable to do that composition. |
| struct _Default_ranged_hash { }; |
| |
| // Default value for rehash policy. Bucket size is (usually) the |
| // smallest prime that keeps the load factor small enough. |
| struct _Prime_rehash_policy |
| { |
| _Prime_rehash_policy(float __z = 1.0); |
| |
| float |
| max_load_factor() const; |
| |
| // Return a bucket size no smaller than n. |
| std::size_t |
| _M_next_bkt(std::size_t __n) const; |
| |
| // Return a bucket count appropriate for n elements |
| std::size_t |
| _M_bkt_for_elements(std::size_t __n) const; |
| |
| // __n_bkt is current bucket count, __n_elt is current element count, |
| // and __n_ins is number of elements to be inserted. Do we need to |
| // increase bucket count? If so, return make_pair(true, n), where n |
| // is the new bucket count. If not, return make_pair(false, 0). |
| std::pair<bool, std::size_t> |
| _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt, |
| std::size_t __n_ins) const; |
| |
| float _M_max_load_factor; |
| float _M_growth_factor; |
| mutable std::size_t _M_next_resize; |
| }; |
| |
| inline |
| _Prime_rehash_policy:: |
| _Prime_rehash_policy(float __z) |
| : _M_max_load_factor(__z), _M_growth_factor(2.f), _M_next_resize(0) |
| { } |
| |
| inline float |
| _Prime_rehash_policy:: |
| max_load_factor() const |
| { return _M_max_load_factor; } |
| |
| // Return a prime no smaller than n. |
| inline std::size_t |
| _Prime_rehash_policy:: |
| _M_next_bkt(std::size_t __n) const |
| { |
| const unsigned long* const __last = (_Primes<>::__primes |
| + _Primes<>::__n_primes); |
| const unsigned long* __p = std::lower_bound(_Primes<>::__primes, __last, |
| __n); |
| _M_next_resize = static_cast<std::size_t>(std::ceil(*__p |
| * _M_max_load_factor)); |
| return *__p; |
| } |
| |
| // Return the smallest prime p such that alpha p >= n, where alpha |
| // is the load factor. |
| inline std::size_t |
| _Prime_rehash_policy:: |
| _M_bkt_for_elements(std::size_t __n) const |
| { |
| const unsigned long* const __last = (_Primes<>::__primes |
| + _Primes<>::__n_primes); |
| const float __min_bkts = __n / _M_max_load_factor; |
| const unsigned long* __p = std::lower_bound(_Primes<>::__primes, __last, |
| __min_bkts, _LessThan()); |
| _M_next_resize = static_cast<std::size_t>(std::ceil(*__p |
| * _M_max_load_factor)); |
| return *__p; |
| } |
| |
| // Finds the smallest prime p such that alpha p > __n_elt + __n_ins. |
| // If p > __n_bkt, return make_pair(true, p); otherwise return |
| // make_pair(false, 0). In principle this isn't very different from |
| // _M_bkt_for_elements. |
| |
| // The only tricky part is that we're caching the element count at |
| // which we need to rehash, so we don't have to do a floating-point |
| // multiply for every insertion. |
| |
| inline std::pair<bool, std::size_t> |
| _Prime_rehash_policy:: |
| _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt, |
| std::size_t __n_ins) const |
| { |
| if (__n_elt + __n_ins > _M_next_resize) |
| { |
| float __min_bkts = ((float(__n_ins) + float(__n_elt)) |
| / _M_max_load_factor); |
| if (__min_bkts > __n_bkt) |
| { |
| __min_bkts = std::max(__min_bkts, _M_growth_factor * __n_bkt); |
| const unsigned long* const __last = (_Primes<>::__primes |
| + _Primes<>::__n_primes); |
| const unsigned long* __p = std::lower_bound(_Primes<>::__primes, |
| __last, __min_bkts, |
| _LessThan()); |
| _M_next_resize = |
| static_cast<std::size_t>(std::ceil(*__p * _M_max_load_factor)); |
| return std::make_pair(true, *__p); |
| } |
| else |
| { |
| _M_next_resize = |
| static_cast<std::size_t>(std::ceil(__n_bkt |
| * _M_max_load_factor)); |
| return std::make_pair(false, 0); |
| } |
| } |
| else |
| return std::make_pair(false, 0); |
| } |
| |
| // Base classes for std::tr1::_Hashtable. We define these base |
| // classes because in some cases we want to do different things |
| // depending on the value of a policy class. In some cases the |
| // policy class affects which member functions and nested typedefs |
| // are defined; we handle that by specializing base class templates. |
| // Several of the base class templates need to access other members |
| // of class template _Hashtable, so we use the "curiously recurring |
| // template pattern" for them. |
| |
| // class template _Map_base. If the hashtable has a value type of the |
| // form pair<T1, T2> and a key extraction policy that returns the |
| // first part of the pair, the hashtable gets a mapped_type typedef. |
| // If it satisfies those criteria and also has unique keys, then it |
| // also gets an operator[]. |
| template<typename _Key, typename _Value, typename _Ex, bool __unique, |
| typename _Hashtable> |
| struct _Map_base { }; |
| |
| template<typename _Key, typename _Pair, typename _Hashtable> |
| struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, false, _Hashtable> |
| { |
| typedef typename _Pair::second_type mapped_type; |
| }; |
| |
| template<typename _Key, typename _Pair, typename _Hashtable> |
| struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable> |
| { |
| typedef typename _Pair::second_type mapped_type; |
| |
| mapped_type& |
| operator[](const _Key& __k); |
| }; |
| |
| template<typename _Key, typename _Pair, typename _Hashtable> |
| typename _Map_base<_Key, _Pair, std::_Select1st<_Pair>, |
| true, _Hashtable>::mapped_type& |
| _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>:: |
| operator[](const _Key& __k) |
| { |
| _Hashtable* __h = static_cast<_Hashtable*>(this); |
| typename _Hashtable::_Hash_code_type __code = __h->_M_hash_code(__k); |
| std::size_t __n = __h->_M_bucket_index(__k, __code, |
| __h->_M_bucket_count); |
| |
| typename _Hashtable::_Node* __p = |
| __h->_M_find_node(__h->_M_buckets[__n], __k, __code); |
| if (!__p) |
| return __h->_M_insert_bucket(std::make_pair(__k, mapped_type()), |
| __n, __code)->second; |
| return (__p->_M_v).second; |
| } |
| |
| // class template _Rehash_base. Give hashtable the max_load_factor |
| // functions iff the rehash policy is _Prime_rehash_policy. |
| template<typename _RehashPolicy, typename _Hashtable> |
| struct _Rehash_base { }; |
| |
| template<typename _Hashtable> |
| struct _Rehash_base<_Prime_rehash_policy, _Hashtable> |
| { |
| float |
| max_load_factor() const |
| { |
| const _Hashtable* __this = static_cast<const _Hashtable*>(this); |
| return __this->__rehash_policy().max_load_factor(); |
| } |
| |
| void |
| max_load_factor(float __z) |
| { |
| _Hashtable* __this = static_cast<_Hashtable*>(this); |
| __this->__rehash_policy(_Prime_rehash_policy(__z)); |
| } |
| }; |
| |
| // Class template _Hash_code_base. Encapsulates two policy issues that |
| // aren't quite orthogonal. |
| // (1) the difference between using a ranged hash function and using |
| // the combination of a hash function and a range-hashing function. |
| // In the former case we don't have such things as hash codes, so |
| // we have a dummy type as placeholder. |
| // (2) Whether or not we cache hash codes. Caching hash codes is |
| // meaningless if we have a ranged hash function. |
| // We also put the key extraction and equality comparison function |
| // objects here, for convenience. |
| |
| // Primary template: unused except as a hook for specializations. |
| template<typename _Key, typename _Value, |
| typename _ExtractKey, typename _Equal, |
| typename _H1, typename _H2, typename _Hash, |
| bool __cache_hash_code> |
| struct _Hash_code_base; |
| |
| // Specialization: ranged hash function, no caching hash codes. H1 |
| // and H2 are provided but ignored. We define a dummy hash code type. |
| template<typename _Key, typename _Value, |
| typename _ExtractKey, typename _Equal, |
| typename _H1, typename _H2, typename _Hash> |
| struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, |
| _Hash, false> |
| { |
| protected: |
| _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, |
| const _H1&, const _H2&, const _Hash& __h) |
| : _M_extract(__ex), _M_eq(__eq), _M_ranged_hash(__h) { } |
| |
| typedef void* _Hash_code_type; |
| |
| _Hash_code_type |
| _M_hash_code(const _Key& __key) const |
| { return 0; } |
| |
| std::size_t |
| _M_bucket_index(const _Key& __k, _Hash_code_type, |
| std::size_t __n) const |
| { return _M_ranged_hash(__k, __n); } |
| |
| std::size_t |
| _M_bucket_index(const _Hash_node<_Value, false>* __p, |
| std::size_t __n) const |
| { return _M_ranged_hash(_M_extract(__p->_M_v), __n); } |
| |
| bool |
| _M_compare(const _Key& __k, _Hash_code_type, |
| _Hash_node<_Value, false>* __n) const |
| { return _M_eq(__k, _M_extract(__n->_M_v)); } |
| |
| void |
| _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const |
| { } |
| |
| void |
| _M_copy_code(_Hash_node<_Value, false>*, |
| const _Hash_node<_Value, false>*) const |
| { } |
| |
| void |
| _M_swap(_Hash_code_base& __x) |
| { |
| std::swap(_M_extract, __x._M_extract); |
| std::swap(_M_eq, __x._M_eq); |
| std::swap(_M_ranged_hash, __x._M_ranged_hash); |
| } |
| |
| protected: |
| _ExtractKey _M_extract; |
| _Equal _M_eq; |
| _Hash _M_ranged_hash; |
| }; |
| |
| |
| // No specialization for ranged hash function while caching hash codes. |
| // That combination is meaningless, and trying to do it is an error. |
| |
| |
| // Specialization: ranged hash function, cache hash codes. This |
| // combination is meaningless, so we provide only a declaration |
| // and no definition. |
| template<typename _Key, typename _Value, |
| typename _ExtractKey, typename _Equal, |
| typename _H1, typename _H2, typename _Hash> |
| struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, |
| _Hash, true>; |
| |
| // Specialization: hash function and range-hashing function, no |
| // caching of hash codes. H is provided but ignored. Provides |
| // typedef and accessor required by TR1. |
| template<typename _Key, typename _Value, |
| typename _ExtractKey, typename _Equal, |
| typename _H1, typename _H2> |
| struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, |
| _Default_ranged_hash, false> |
| { |
| typedef _H1 hasher; |
| |
| hasher |
| hash_function() const |
| { return _M_h1; } |
| |
| protected: |
| _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, |
| const _H1& __h1, const _H2& __h2, |
| const _Default_ranged_hash&) |
| : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { } |
| |
| typedef std::size_t _Hash_code_type; |
| |
| _Hash_code_type |
| _M_hash_code(const _Key& __k) const |
| { return _M_h1(__k); } |
| |
| std::size_t |
| _M_bucket_index(const _Key&, _Hash_code_type __c, |
| std::size_t __n) const |
| { return _M_h2(__c, __n); } |
| |
| std::size_t |
| _M_bucket_index(const _Hash_node<_Value, false>* __p, |
| std::size_t __n) const |
| { return _M_h2(_M_h1(_M_extract(__p->_M_v)), __n); } |
| |
| bool |
| _M_compare(const _Key& __k, _Hash_code_type, |
| _Hash_node<_Value, false>* __n) const |
| { return _M_eq(__k, _M_extract(__n->_M_v)); } |
| |
| void |
| _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const |
| { } |
| |
| void |
| _M_copy_code(_Hash_node<_Value, false>*, |
| const _Hash_node<_Value, false>*) const |
| { } |
| |
| void |
| _M_swap(_Hash_code_base& __x) |
| { |
| std::swap(_M_extract, __x._M_extract); |
| std::swap(_M_eq, __x._M_eq); |
| std::swap(_M_h1, __x._M_h1); |
| std::swap(_M_h2, __x._M_h2); |
| } |
| |
| protected: |
| _ExtractKey _M_extract; |
| _Equal _M_eq; |
| _H1 _M_h1; |
| _H2 _M_h2; |
| }; |
| |
| // Specialization: hash function and range-hashing function, |
| // caching hash codes. H is provided but ignored. Provides |
| // typedef and accessor required by TR1. |
| template<typename _Key, typename _Value, |
| typename _ExtractKey, typename _Equal, |
| typename _H1, typename _H2> |
| struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, |
| _Default_ranged_hash, true> |
| { |
| typedef _H1 hasher; |
| |
| hasher |
| hash_function() const |
| { return _M_h1; } |
| |
| protected: |
| _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, |
| const _H1& __h1, const _H2& __h2, |
| const _Default_ranged_hash&) |
| : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { } |
| |
| typedef std::size_t _Hash_code_type; |
| |
| _Hash_code_type |
| _M_hash_code(const _Key& __k) const |
| { return _M_h1(__k); } |
| |
| std::size_t |
| _M_bucket_index(const _Key&, _Hash_code_type __c, |
| std::size_t __n) const |
| { return _M_h2(__c, __n); } |
| |
| std::size_t |
| _M_bucket_index(const _Hash_node<_Value, true>* __p, |
| std::size_t __n) const |
| { return _M_h2(__p->_M_hash_code, __n); } |
| |
| bool |
| _M_compare(const _Key& __k, _Hash_code_type __c, |
| _Hash_node<_Value, true>* __n) const |
| { return __c == __n->_M_hash_code && _M_eq(__k, _M_extract(__n->_M_v)); } |
| |
| void |
| _M_store_code(_Hash_node<_Value, true>* __n, _Hash_code_type __c) const |
| { __n->_M_hash_code = __c; } |
| |
| void |
| _M_copy_code(_Hash_node<_Value, true>* __to, |
| const _Hash_node<_Value, true>* __from) const |
| { __to->_M_hash_code = __from->_M_hash_code; } |
| |
| void |
| _M_swap(_Hash_code_base& __x) |
| { |
| std::swap(_M_extract, __x._M_extract); |
| std::swap(_M_eq, __x._M_eq); |
| std::swap(_M_h1, __x._M_h1); |
| std::swap(_M_h2, __x._M_h2); |
| } |
| |
| protected: |
| _ExtractKey _M_extract; |
| _Equal _M_eq; |
| _H1 _M_h1; |
| _H2 _M_h2; |
| }; |
| } // namespace __detail |
| _GLIBCXX_END_NAMESPACE |
| } // namespace std::tr1 |
| |
| #endif // _TR1_HASHTABLE_POLICY_H |
| |
