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1 // Internal policy header for TR1 unordered_set and unordered_map -*- C++ -*-
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2
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145
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3 // Copyright (C) 2010-2020 Free Software Foundation, Inc.
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111
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4 //
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5 // This file is part of the GNU ISO C++ Library. This library is free
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6 // software; you can redistribute it and/or modify it under the
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7 // terms of the GNU General Public License as published by the
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8 // Free Software Foundation; either version 3, or (at your option)
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9 // any later version.
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10
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11 // This library is distributed in the hope that it will be useful,
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12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 // GNU General Public License for more details.
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15
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16 // Under Section 7 of GPL version 3, you are granted additional
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17 // permissions described in the GCC Runtime Library Exception, version
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18 // 3.1, as published by the Free Software Foundation.
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19
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20 // You should have received a copy of the GNU General Public License and
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21 // a copy of the GCC Runtime Library Exception along with this program;
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22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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23 // <http://www.gnu.org/licenses/>.
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24
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25 /** @file tr1/hashtable_policy.h
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26 * This is an internal header file, included by other library headers.
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27 * Do not attempt to use it directly.
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28 * @headername{tr1/unordered_map, tr1/unordered_set}
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29 */
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30
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31 namespace std _GLIBCXX_VISIBILITY(default)
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32 {
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33 _GLIBCXX_BEGIN_NAMESPACE_VERSION
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34
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35 namespace tr1
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36 {
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37 namespace __detail
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38 {
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39 // Helper function: return distance(first, last) for forward
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40 // iterators, or 0 for input iterators.
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41 template<class _Iterator>
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42 inline typename std::iterator_traits<_Iterator>::difference_type
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43 __distance_fw(_Iterator __first, _Iterator __last,
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44 std::input_iterator_tag)
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45 { return 0; }
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46
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47 template<class _Iterator>
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48 inline typename std::iterator_traits<_Iterator>::difference_type
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49 __distance_fw(_Iterator __first, _Iterator __last,
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50 std::forward_iterator_tag)
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51 { return std::distance(__first, __last); }
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52
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53 template<class _Iterator>
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54 inline typename std::iterator_traits<_Iterator>::difference_type
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55 __distance_fw(_Iterator __first, _Iterator __last)
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56 {
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57 typedef typename std::iterator_traits<_Iterator>::iterator_category _Tag;
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58 return __distance_fw(__first, __last, _Tag());
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59 }
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60
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61 // Auxiliary types used for all instantiations of _Hashtable: nodes
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62 // and iterators.
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63
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64 // Nodes, used to wrap elements stored in the hash table. A policy
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65 // template parameter of class template _Hashtable controls whether
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66 // nodes also store a hash code. In some cases (e.g. strings) this
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67 // may be a performance win.
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68 template<typename _Value, bool __cache_hash_code>
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69 struct _Hash_node;
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70
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71 template<typename _Value>
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72 struct _Hash_node<_Value, true>
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73 {
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74 _Value _M_v;
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75 std::size_t _M_hash_code;
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76 _Hash_node* _M_next;
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77 };
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78
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79 template<typename _Value>
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80 struct _Hash_node<_Value, false>
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81 {
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82 _Value _M_v;
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83 _Hash_node* _M_next;
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84 };
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85
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86 // Local iterators, used to iterate within a bucket but not between
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87 // buckets.
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88 template<typename _Value, bool __cache>
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89 struct _Node_iterator_base
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90 {
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91 _Node_iterator_base(_Hash_node<_Value, __cache>* __p)
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92 : _M_cur(__p) { }
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93
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94 void
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95 _M_incr()
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96 { _M_cur = _M_cur->_M_next; }
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97
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98 _Hash_node<_Value, __cache>* _M_cur;
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99 };
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100
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101 template<typename _Value, bool __cache>
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102 inline bool
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103 operator==(const _Node_iterator_base<_Value, __cache>& __x,
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104 const _Node_iterator_base<_Value, __cache>& __y)
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105 { return __x._M_cur == __y._M_cur; }
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106
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107 template<typename _Value, bool __cache>
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108 inline bool
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109 operator!=(const _Node_iterator_base<_Value, __cache>& __x,
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110 const _Node_iterator_base<_Value, __cache>& __y)
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111 { return __x._M_cur != __y._M_cur; }
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112
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113 template<typename _Value, bool __constant_iterators, bool __cache>
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114 struct _Node_iterator
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115 : public _Node_iterator_base<_Value, __cache>
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116 {
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117 typedef _Value value_type;
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118 typedef typename
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119 __gnu_cxx::__conditional_type<__constant_iterators,
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120 const _Value*, _Value*>::__type
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121 pointer;
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122 typedef typename
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123 __gnu_cxx::__conditional_type<__constant_iterators,
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124 const _Value&, _Value&>::__type
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125 reference;
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126 typedef std::ptrdiff_t difference_type;
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127 typedef std::forward_iterator_tag iterator_category;
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128
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129 _Node_iterator()
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130 : _Node_iterator_base<_Value, __cache>(0) { }
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131
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132 explicit
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133 _Node_iterator(_Hash_node<_Value, __cache>* __p)
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134 : _Node_iterator_base<_Value, __cache>(__p) { }
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135
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136 reference
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137 operator*() const
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138 { return this->_M_cur->_M_v; }
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139
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140 pointer
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141 operator->() const
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142 { return std::__addressof(this->_M_cur->_M_v); }
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143
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144 _Node_iterator&
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145 operator++()
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146 {
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147 this->_M_incr();
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148 return *this;
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149 }
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150
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151 _Node_iterator
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152 operator++(int)
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153 {
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154 _Node_iterator __tmp(*this);
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155 this->_M_incr();
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156 return __tmp;
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157 }
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158 };
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159
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160 template<typename _Value, bool __constant_iterators, bool __cache>
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161 struct _Node_const_iterator
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162 : public _Node_iterator_base<_Value, __cache>
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163 {
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164 typedef _Value value_type;
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165 typedef const _Value* pointer;
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166 typedef const _Value& reference;
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167 typedef std::ptrdiff_t difference_type;
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168 typedef std::forward_iterator_tag iterator_category;
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169
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170 _Node_const_iterator()
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171 : _Node_iterator_base<_Value, __cache>(0) { }
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172
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173 explicit
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174 _Node_const_iterator(_Hash_node<_Value, __cache>* __p)
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175 : _Node_iterator_base<_Value, __cache>(__p) { }
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176
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177 _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
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178 __cache>& __x)
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179 : _Node_iterator_base<_Value, __cache>(__x._M_cur) { }
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180
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181 reference
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182 operator*() const
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183 { return this->_M_cur->_M_v; }
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184
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185 pointer
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186 operator->() const
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187 { return std::__addressof(this->_M_cur->_M_v); }
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188
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189 _Node_const_iterator&
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190 operator++()
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191 {
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192 this->_M_incr();
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193 return *this;
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194 }
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195
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196 _Node_const_iterator
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197 operator++(int)
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198 {
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199 _Node_const_iterator __tmp(*this);
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200 this->_M_incr();
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201 return __tmp;
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202 }
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203 };
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204
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205 template<typename _Value, bool __cache>
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206 struct _Hashtable_iterator_base
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207 {
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208 _Hashtable_iterator_base(_Hash_node<_Value, __cache>* __node,
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209 _Hash_node<_Value, __cache>** __bucket)
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210 : _M_cur_node(__node), _M_cur_bucket(__bucket) { }
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211
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212 void
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213 _M_incr()
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214 {
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215 _M_cur_node = _M_cur_node->_M_next;
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216 if (!_M_cur_node)
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217 _M_incr_bucket();
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218 }
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219
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220 void
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221 _M_incr_bucket();
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222
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223 _Hash_node<_Value, __cache>* _M_cur_node;
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224 _Hash_node<_Value, __cache>** _M_cur_bucket;
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225 };
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226
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227 // Global iterators, used for arbitrary iteration within a hash
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228 // table. Larger and more expensive than local iterators.
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229 template<typename _Value, bool __cache>
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230 void
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231 _Hashtable_iterator_base<_Value, __cache>::
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232 _M_incr_bucket()
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233 {
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234 ++_M_cur_bucket;
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235
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236 // This loop requires the bucket array to have a non-null sentinel.
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237 while (!*_M_cur_bucket)
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238 ++_M_cur_bucket;
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239 _M_cur_node = *_M_cur_bucket;
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240 }
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241
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242 template<typename _Value, bool __cache>
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243 inline bool
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244 operator==(const _Hashtable_iterator_base<_Value, __cache>& __x,
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245 const _Hashtable_iterator_base<_Value, __cache>& __y)
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246 { return __x._M_cur_node == __y._M_cur_node; }
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247
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248 template<typename _Value, bool __cache>
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249 inline bool
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250 operator!=(const _Hashtable_iterator_base<_Value, __cache>& __x,
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251 const _Hashtable_iterator_base<_Value, __cache>& __y)
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252 { return __x._M_cur_node != __y._M_cur_node; }
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253
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254 template<typename _Value, bool __constant_iterators, bool __cache>
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255 struct _Hashtable_iterator
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256 : public _Hashtable_iterator_base<_Value, __cache>
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257 {
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258 typedef _Value value_type;
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259 typedef typename
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260 __gnu_cxx::__conditional_type<__constant_iterators,
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261 const _Value*, _Value*>::__type
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262 pointer;
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263 typedef typename
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264 __gnu_cxx::__conditional_type<__constant_iterators,
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265 const _Value&, _Value&>::__type
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266 reference;
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267 typedef std::ptrdiff_t difference_type;
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268 typedef std::forward_iterator_tag iterator_category;
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269
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270 _Hashtable_iterator()
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271 : _Hashtable_iterator_base<_Value, __cache>(0, 0) { }
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272
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273 _Hashtable_iterator(_Hash_node<_Value, __cache>* __p,
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274 _Hash_node<_Value, __cache>** __b)
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275 : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { }
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276
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277 explicit
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278 _Hashtable_iterator(_Hash_node<_Value, __cache>** __b)
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279 : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { }
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280
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281 reference
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282 operator*() const
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283 { return this->_M_cur_node->_M_v; }
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284
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285 pointer
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286 operator->() const
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287 { return std::__addressof(this->_M_cur_node->_M_v); }
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288
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289 _Hashtable_iterator&
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290 operator++()
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291 {
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292 this->_M_incr();
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293 return *this;
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294 }
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295
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296 _Hashtable_iterator
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297 operator++(int)
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298 {
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299 _Hashtable_iterator __tmp(*this);
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300 this->_M_incr();
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301 return __tmp;
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302 }
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303 };
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304
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305 template<typename _Value, bool __constant_iterators, bool __cache>
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306 struct _Hashtable_const_iterator
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307 : public _Hashtable_iterator_base<_Value, __cache>
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308 {
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309 typedef _Value value_type;
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310 typedef const _Value* pointer;
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311 typedef const _Value& reference;
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312 typedef std::ptrdiff_t difference_type;
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313 typedef std::forward_iterator_tag iterator_category;
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314
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315 _Hashtable_const_iterator()
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316 : _Hashtable_iterator_base<_Value, __cache>(0, 0) { }
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317
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318 _Hashtable_const_iterator(_Hash_node<_Value, __cache>* __p,
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319 _Hash_node<_Value, __cache>** __b)
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320 : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { }
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321
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322 explicit
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323 _Hashtable_const_iterator(_Hash_node<_Value, __cache>** __b)
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324 : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { }
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325
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326 _Hashtable_const_iterator(const _Hashtable_iterator<_Value,
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327 __constant_iterators, __cache>& __x)
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328 : _Hashtable_iterator_base<_Value, __cache>(__x._M_cur_node,
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329 __x._M_cur_bucket) { }
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330
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331 reference
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332 operator*() const
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333 { return this->_M_cur_node->_M_v; }
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334
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335 pointer
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336 operator->() const
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337 { return std::__addressof(this->_M_cur_node->_M_v); }
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338
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339 _Hashtable_const_iterator&
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340 operator++()
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341 {
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342 this->_M_incr();
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343 return *this;
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344 }
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345
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346 _Hashtable_const_iterator
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347 operator++(int)
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348 {
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349 _Hashtable_const_iterator __tmp(*this);
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350 this->_M_incr();
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351 return __tmp;
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352 }
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353 };
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354
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355
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356 // Many of class template _Hashtable's template parameters are policy
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357 // classes. These are defaults for the policies.
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358
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359 // Default range hashing function: use division to fold a large number
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360 // into the range [0, N).
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361 struct _Mod_range_hashing
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362 {
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363 typedef std::size_t first_argument_type;
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364 typedef std::size_t second_argument_type;
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365 typedef std::size_t result_type;
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366
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367 result_type
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368 operator()(first_argument_type __num, second_argument_type __den) const
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369 { return __num % __den; }
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370 };
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371
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372 // Default ranged hash function H. In principle it should be a
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373 // function object composed from objects of type H1 and H2 such that
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374 // h(k, N) = h2(h1(k), N), but that would mean making extra copies of
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375 // h1 and h2. So instead we'll just use a tag to tell class template
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376 // hashtable to do that composition.
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377 struct _Default_ranged_hash { };
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378
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379 // Default value for rehash policy. Bucket size is (usually) the
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380 // smallest prime that keeps the load factor small enough.
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381 struct _Prime_rehash_policy
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382 {
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383 _Prime_rehash_policy(float __z = 1.0)
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384 : _M_max_load_factor(__z), _M_growth_factor(2.f), _M_next_resize(0) { }
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385
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386 float
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387 max_load_factor() const
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388 { return _M_max_load_factor; }
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389
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390 // Return a bucket size no smaller than n.
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391 std::size_t
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392 _M_next_bkt(std::size_t __n) const;
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393
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394 // Return a bucket count appropriate for n elements
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395 std::size_t
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396 _M_bkt_for_elements(std::size_t __n) const;
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397
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398 // __n_bkt is current bucket count, __n_elt is current element count,
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399 // and __n_ins is number of elements to be inserted. Do we need to
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400 // increase bucket count? If so, return make_pair(true, n), where n
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401 // is the new bucket count. If not, return make_pair(false, 0).
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402 std::pair<bool, std::size_t>
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403 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
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404 std::size_t __n_ins) const;
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405
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406 enum { _S_n_primes = sizeof(unsigned long) != 8 ? 256 : 256 + 48 };
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407
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408 float _M_max_load_factor;
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409 float _M_growth_factor;
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410 mutable std::size_t _M_next_resize;
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411 };
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412
|
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|
413 extern const unsigned long __prime_list[];
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414
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415 // XXX This is a hack. There's no good reason for any of
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|
416 // _Prime_rehash_policy's member functions to be inline.
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417
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|
418 // Return a prime no smaller than n.
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|
|
419 inline std::size_t
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|
420 _Prime_rehash_policy::
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421 _M_next_bkt(std::size_t __n) const
|
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|
422 {
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|
423 // Don't include the last prime in the search, so that anything
|
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|
424 // higher than the second-to-last prime returns a past-the-end
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|
425 // iterator that can be dereferenced to get the last prime.
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|
|
426 const unsigned long* __p
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|
|
427 = std::lower_bound(__prime_list, __prime_list + _S_n_primes - 1, __n);
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|
|
428 _M_next_resize =
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|
429 static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor));
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430 return *__p;
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|
|
431 }
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|
432
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|
433 // Return the smallest prime p such that alpha p >= n, where alpha
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|
434 // is the load factor.
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|
435 inline std::size_t
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436 _Prime_rehash_policy::
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437 _M_bkt_for_elements(std::size_t __n) const
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438 {
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|
439 const float __min_bkts = __n / _M_max_load_factor;
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440 return _M_next_bkt(__builtin_ceil(__min_bkts));
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441 }
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442
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443 // Finds the smallest prime p such that alpha p > __n_elt + __n_ins.
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444 // If p > __n_bkt, return make_pair(true, p); otherwise return
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445 // make_pair(false, 0). In principle this isn't very different from
|
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446 // _M_bkt_for_elements.
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447
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|
448 // The only tricky part is that we're caching the element count at
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449 // which we need to rehash, so we don't have to do a floating-point
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450 // multiply for every insertion.
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451
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452 inline std::pair<bool, std::size_t>
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453 _Prime_rehash_policy::
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454 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
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|
455 std::size_t __n_ins) const
|
|
|
456 {
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|
|
457 if (__n_elt + __n_ins > _M_next_resize)
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|
458 {
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|
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459 float __min_bkts = ((float(__n_ins) + float(__n_elt))
|
|
|
460 / _M_max_load_factor);
|
|
|
461 if (__min_bkts > __n_bkt)
|
|
|
462 {
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|
463 __min_bkts = std::max(__min_bkts, _M_growth_factor * __n_bkt);
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|
464 return std::make_pair(true,
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|
465 _M_next_bkt(__builtin_ceil(__min_bkts)));
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|
466 }
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|
|
467 else
|
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|
468 {
|
|
|
469 _M_next_resize = static_cast<std::size_t>
|
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|
470 (__builtin_ceil(__n_bkt * _M_max_load_factor));
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|
471 return std::make_pair(false, 0);
|
|
|
472 }
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|
|
473 }
|
|
|
474 else
|
|
|
475 return std::make_pair(false, 0);
|
|
|
476 }
|
|
|
477
|
|
|
478 // Base classes for std::tr1::_Hashtable. We define these base
|
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|
479 // classes because in some cases we want to do different things
|
|
|
480 // depending on the value of a policy class. In some cases the
|
|
|
481 // policy class affects which member functions and nested typedefs
|
|
|
482 // are defined; we handle that by specializing base class templates.
|
|
|
483 // Several of the base class templates need to access other members
|
|
|
484 // of class template _Hashtable, so we use the "curiously recurring
|
|
|
485 // template pattern" for them.
|
|
|
486
|
|
|
487 // class template _Map_base. If the hashtable has a value type of the
|
|
|
488 // form pair<T1, T2> and a key extraction policy that returns the
|
|
|
489 // first part of the pair, the hashtable gets a mapped_type typedef.
|
|
|
490 // If it satisfies those criteria and also has unique keys, then it
|
|
|
491 // also gets an operator[].
|
|
|
492 template<typename _Key, typename _Value, typename _Ex, bool __unique,
|
|
|
493 typename _Hashtable>
|
|
|
494 struct _Map_base { };
|
|
|
495
|
|
|
496 template<typename _Key, typename _Pair, typename _Hashtable>
|
|
|
497 struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, false, _Hashtable>
|
|
|
498 {
|
|
|
499 typedef typename _Pair::second_type mapped_type;
|
|
|
500 };
|
|
|
501
|
|
|
502 template<typename _Key, typename _Pair, typename _Hashtable>
|
|
|
503 struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>
|
|
|
504 {
|
|
|
505 typedef typename _Pair::second_type mapped_type;
|
|
|
506
|
|
|
507 mapped_type&
|
|
|
508 operator[](const _Key& __k);
|
|
|
509 };
|
|
|
510
|
|
|
511 template<typename _Key, typename _Pair, typename _Hashtable>
|
|
|
512 typename _Map_base<_Key, _Pair, std::_Select1st<_Pair>,
|
|
|
513 true, _Hashtable>::mapped_type&
|
|
|
514 _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::
|
|
|
515 operator[](const _Key& __k)
|
|
|
516 {
|
|
|
517 _Hashtable* __h = static_cast<_Hashtable*>(this);
|
|
|
518 typename _Hashtable::_Hash_code_type __code = __h->_M_hash_code(__k);
|
|
|
519 std::size_t __n = __h->_M_bucket_index(__k, __code,
|
|
|
520 __h->_M_bucket_count);
|
|
|
521
|
|
|
522 typename _Hashtable::_Node* __p =
|
|
|
523 __h->_M_find_node(__h->_M_buckets[__n], __k, __code);
|
|
|
524 if (!__p)
|
|
|
525 return __h->_M_insert_bucket(std::make_pair(__k, mapped_type()),
|
|
|
526 __n, __code)->second;
|
|
|
527 return (__p->_M_v).second;
|
|
|
528 }
|
|
|
529
|
|
|
530 // class template _Rehash_base. Give hashtable the max_load_factor
|
|
|
531 // functions iff the rehash policy is _Prime_rehash_policy.
|
|
|
532 template<typename _RehashPolicy, typename _Hashtable>
|
|
|
533 struct _Rehash_base { };
|
|
|
534
|
|
|
535 template<typename _Hashtable>
|
|
|
536 struct _Rehash_base<_Prime_rehash_policy, _Hashtable>
|
|
|
537 {
|
|
|
538 float
|
|
|
539 max_load_factor() const
|
|
|
540 {
|
|
|
541 const _Hashtable* __this = static_cast<const _Hashtable*>(this);
|
|
|
542 return __this->__rehash_policy().max_load_factor();
|
|
|
543 }
|
|
|
544
|
|
|
545 void
|
|
|
546 max_load_factor(float __z)
|
|
|
547 {
|
|
|
548 _Hashtable* __this = static_cast<_Hashtable*>(this);
|
|
|
549 __this->__rehash_policy(_Prime_rehash_policy(__z));
|
|
|
550 }
|
|
|
551 };
|
|
|
552
|
|
|
553 // Class template _Hash_code_base. Encapsulates two policy issues that
|
|
|
554 // aren't quite orthogonal.
|
|
|
555 // (1) the difference between using a ranged hash function and using
|
|
|
556 // the combination of a hash function and a range-hashing function.
|
|
|
557 // In the former case we don't have such things as hash codes, so
|
|
|
558 // we have a dummy type as placeholder.
|
|
|
559 // (2) Whether or not we cache hash codes. Caching hash codes is
|
|
|
560 // meaningless if we have a ranged hash function.
|
|
|
561 // We also put the key extraction and equality comparison function
|
|
|
562 // objects here, for convenience.
|
|
|
563
|
|
|
564 // Primary template: unused except as a hook for specializations.
|
|
|
565 template<typename _Key, typename _Value,
|
|
|
566 typename _ExtractKey, typename _Equal,
|
|
|
567 typename _H1, typename _H2, typename _Hash,
|
|
|
568 bool __cache_hash_code>
|
|
|
569 struct _Hash_code_base;
|
|
|
570
|
|
|
571 // Specialization: ranged hash function, no caching hash codes. H1
|
|
|
572 // and H2 are provided but ignored. We define a dummy hash code type.
|
|
|
573 template<typename _Key, typename _Value,
|
|
|
574 typename _ExtractKey, typename _Equal,
|
|
|
575 typename _H1, typename _H2, typename _Hash>
|
|
|
576 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2,
|
|
|
577 _Hash, false>
|
|
|
578 {
|
|
|
579 protected:
|
|
|
580 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq,
|
|
|
581 const _H1&, const _H2&, const _Hash& __h)
|
|
|
582 : _M_extract(__ex), _M_eq(__eq), _M_ranged_hash(__h) { }
|
|
|
583
|
|
|
584 typedef void* _Hash_code_type;
|
|
|
585
|
|
|
586 _Hash_code_type
|
|
|
587 _M_hash_code(const _Key& __key) const
|
|
|
588 { return 0; }
|
|
|
589
|
|
|
590 std::size_t
|
|
|
591 _M_bucket_index(const _Key& __k, _Hash_code_type,
|
|
|
592 std::size_t __n) const
|
|
|
593 { return _M_ranged_hash(__k, __n); }
|
|
|
594
|
|
|
595 std::size_t
|
|
|
596 _M_bucket_index(const _Hash_node<_Value, false>* __p,
|
|
|
597 std::size_t __n) const
|
|
|
598 { return _M_ranged_hash(_M_extract(__p->_M_v), __n); }
|
|
|
599
|
|
|
600 bool
|
|
|
601 _M_compare(const _Key& __k, _Hash_code_type,
|
|
|
602 _Hash_node<_Value, false>* __n) const
|
|
|
603 { return _M_eq(__k, _M_extract(__n->_M_v)); }
|
|
|
604
|
|
|
605 void
|
|
|
606 _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const
|
|
|
607 { }
|
|
|
608
|
|
|
609 void
|
|
|
610 _M_copy_code(_Hash_node<_Value, false>*,
|
|
|
611 const _Hash_node<_Value, false>*) const
|
|
|
612 { }
|
|
|
613
|
|
|
614 void
|
|
|
615 _M_swap(_Hash_code_base& __x)
|
|
|
616 {
|
|
|
617 std::swap(_M_extract, __x._M_extract);
|
|
|
618 std::swap(_M_eq, __x._M_eq);
|
|
|
619 std::swap(_M_ranged_hash, __x._M_ranged_hash);
|
|
|
620 }
|
|
|
621
|
|
|
622 protected:
|
|
|
623 _ExtractKey _M_extract;
|
|
|
624 _Equal _M_eq;
|
|
|
625 _Hash _M_ranged_hash;
|
|
|
626 };
|
|
|
627
|
|
|
628
|
|
|
629 // No specialization for ranged hash function while caching hash codes.
|
|
|
630 // That combination is meaningless, and trying to do it is an error.
|
|
|
631
|
|
|
632
|
|
|
633 // Specialization: ranged hash function, cache hash codes. This
|
|
|
634 // combination is meaningless, so we provide only a declaration
|
|
|
635 // and no definition.
|
|
|
636 template<typename _Key, typename _Value,
|
|
|
637 typename _ExtractKey, typename _Equal,
|
|
|
638 typename _H1, typename _H2, typename _Hash>
|
|
|
639 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2,
|
|
|
640 _Hash, true>;
|
|
|
641
|
|
|
642 // Specialization: hash function and range-hashing function, no
|
|
|
643 // caching of hash codes. H is provided but ignored. Provides
|
|
|
644 // typedef and accessor required by TR1.
|
|
|
645 template<typename _Key, typename _Value,
|
|
|
646 typename _ExtractKey, typename _Equal,
|
|
|
647 typename _H1, typename _H2>
|
|
|
648 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2,
|
|
|
649 _Default_ranged_hash, false>
|
|
|
650 {
|
|
|
651 typedef _H1 hasher;
|
|
|
652
|
|
|
653 hasher
|
|
|
654 hash_function() const
|
|
|
655 { return _M_h1; }
|
|
|
656
|
|
|
657 protected:
|
|
|
658 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq,
|
|
|
659 const _H1& __h1, const _H2& __h2,
|
|
|
660 const _Default_ranged_hash&)
|
|
|
661 : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { }
|
|
|
662
|
|
|
663 typedef std::size_t _Hash_code_type;
|
|
|
664
|
|
|
665 _Hash_code_type
|
|
|
666 _M_hash_code(const _Key& __k) const
|
|
|
667 { return _M_h1(__k); }
|
|
|
668
|
|
|
669 std::size_t
|
|
|
670 _M_bucket_index(const _Key&, _Hash_code_type __c,
|
|
|
671 std::size_t __n) const
|
|
|
672 { return _M_h2(__c, __n); }
|
|
|
673
|
|
|
674 std::size_t
|
|
|
675 _M_bucket_index(const _Hash_node<_Value, false>* __p,
|
|
|
676 std::size_t __n) const
|
|
|
677 { return _M_h2(_M_h1(_M_extract(__p->_M_v)), __n); }
|
|
|
678
|
|
|
679 bool
|
|
|
680 _M_compare(const _Key& __k, _Hash_code_type,
|
|
|
681 _Hash_node<_Value, false>* __n) const
|
|
|
682 { return _M_eq(__k, _M_extract(__n->_M_v)); }
|
|
|
683
|
|
|
684 void
|
|
|
685 _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const
|
|
|
686 { }
|
|
|
687
|
|
|
688 void
|
|
|
689 _M_copy_code(_Hash_node<_Value, false>*,
|
|
|
690 const _Hash_node<_Value, false>*) const
|
|
|
691 { }
|
|
|
692
|
|
|
693 void
|
|
|
694 _M_swap(_Hash_code_base& __x)
|
|
|
695 {
|
|
|
696 std::swap(_M_extract, __x._M_extract);
|
|
|
697 std::swap(_M_eq, __x._M_eq);
|
|
|
698 std::swap(_M_h1, __x._M_h1);
|
|
|
699 std::swap(_M_h2, __x._M_h2);
|
|
|
700 }
|
|
|
701
|
|
|
702 protected:
|
|
|
703 _ExtractKey _M_extract;
|
|
|
704 _Equal _M_eq;
|
|
|
705 _H1 _M_h1;
|
|
|
706 _H2 _M_h2;
|
|
|
707 };
|
|
|
708
|
|
|
709 // Specialization: hash function and range-hashing function,
|
|
|
710 // caching hash codes. H is provided but ignored. Provides
|
|
|
711 // typedef and accessor required by TR1.
|
|
|
712 template<typename _Key, typename _Value,
|
|
|
713 typename _ExtractKey, typename _Equal,
|
|
|
714 typename _H1, typename _H2>
|
|
|
715 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2,
|
|
|
716 _Default_ranged_hash, true>
|
|
|
717 {
|
|
|
718 typedef _H1 hasher;
|
|
|
719
|
|
|
720 hasher
|
|
|
721 hash_function() const
|
|
|
722 { return _M_h1; }
|
|
|
723
|
|
|
724 protected:
|
|
|
725 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq,
|
|
|
726 const _H1& __h1, const _H2& __h2,
|
|
|
727 const _Default_ranged_hash&)
|
|
|
728 : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { }
|
|
|
729
|
|
|
730 typedef std::size_t _Hash_code_type;
|
|
|
731
|
|
|
732 _Hash_code_type
|
|
|
733 _M_hash_code(const _Key& __k) const
|
|
|
734 { return _M_h1(__k); }
|
|
|
735
|
|
|
736 std::size_t
|
|
|
737 _M_bucket_index(const _Key&, _Hash_code_type __c,
|
|
|
738 std::size_t __n) const
|
|
|
739 { return _M_h2(__c, __n); }
|
|
|
740
|
|
|
741 std::size_t
|
|
|
742 _M_bucket_index(const _Hash_node<_Value, true>* __p,
|
|
|
743 std::size_t __n) const
|
|
|
744 { return _M_h2(__p->_M_hash_code, __n); }
|
|
|
745
|
|
|
746 bool
|
|
|
747 _M_compare(const _Key& __k, _Hash_code_type __c,
|
|
|
748 _Hash_node<_Value, true>* __n) const
|
|
|
749 { return __c == __n->_M_hash_code && _M_eq(__k, _M_extract(__n->_M_v)); }
|
|
|
750
|
|
|
751 void
|
|
|
752 _M_store_code(_Hash_node<_Value, true>* __n, _Hash_code_type __c) const
|
|
|
753 { __n->_M_hash_code = __c; }
|
|
|
754
|
|
|
755 void
|
|
|
756 _M_copy_code(_Hash_node<_Value, true>* __to,
|
|
|
757 const _Hash_node<_Value, true>* __from) const
|
|
|
758 { __to->_M_hash_code = __from->_M_hash_code; }
|
|
|
759
|
|
|
760 void
|
|
|
761 _M_swap(_Hash_code_base& __x)
|
|
|
762 {
|
|
|
763 std::swap(_M_extract, __x._M_extract);
|
|
|
764 std::swap(_M_eq, __x._M_eq);
|
|
|
765 std::swap(_M_h1, __x._M_h1);
|
|
|
766 std::swap(_M_h2, __x._M_h2);
|
|
|
767 }
|
|
|
768
|
|
|
769 protected:
|
|
|
770 _ExtractKey _M_extract;
|
|
|
771 _Equal _M_eq;
|
|
|
772 _H1 _M_h1;
|
|
|
773 _H2 _M_h2;
|
|
|
774 };
|
|
|
775 } // namespace __detail
|
|
|
776 }
|
|
|
777
|
|
|
778 _GLIBCXX_END_NAMESPACE_VERSION
|
|
|
779 }
|
