1 // -*- C++ -*- 2 3 // Copyright (C) 2005-2018 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the terms 7 // of the GNU General Public License as published by the Free Software 8 // Foundation; either version 3, or (at your option) any later 9 // version. 10 11 // This library is distributed in the hope that it will be useful, but 12 // WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 // General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. 26 27 // Permission to use, copy, modify, sell, and distribute this software 28 // is hereby granted without fee, provided that the above copyright 29 // notice appears in all copies, and that both that copyright notice 30 // and this permission notice appear in supporting documentation. None 31 // of the above authors, nor IBM Haifa Research Laboratories, make any 32 // representation about the suitability of this software for any 33 // purpose. It is provided "as is" without express or implied 34 // warranty. 35 36 /** 37 * @file trie_policy/trie_policy_base.hpp 38 * Contains an implementation of trie_policy_base. 39 */ 40 41 #ifndef PB_DS_TRIE_POLICY_BASE_HPP 42 #define PB_DS_TRIE_POLICY_BASE_HPP 43 44 #include <ext/pb_ds/detail/branch_policy/branch_policy.hpp> 45 46 namespace __gnu_pbds 47 { 48 namespace detail 49 { 50 /// Base class for trie policies. 51 template<typename Node_CItr, typename Node_Itr, 52 typename _ATraits, typename _Alloc> 53 class trie_policy_base 54 : public branch_policy<Node_CItr, Node_Itr, _Alloc> 55 { 56 typedef branch_policy<Node_CItr, Node_Itr, _Alloc> base_type; 57 58 public: 59 typedef _ATraits access_traits; 60 typedef _Alloc allocator_type; 61 typedef typename allocator_type::size_type size_type; 62 typedef null_type metadata_type; 63 typedef Node_CItr node_const_iterator; 64 typedef Node_Itr node_iterator; 65 typedef typename node_const_iterator::value_type const_iterator; 66 typedef typename node_iterator::value_type iterator; 67 typedef typename base_type::key_type key_type; 68 typedef typename base_type::key_const_reference key_const_reference; 69 70 protected: 71 virtual const_iterator 72 end() const = 0; 73 74 virtual iterator 75 end() = 0; 76 77 virtual node_const_iterator 78 node_begin() const = 0; 79 80 virtual node_iterator 81 node_begin() = 0; 82 83 virtual node_const_iterator 84 node_end() const = 0; 85 86 virtual node_iterator 87 node_end() = 0; 88 89 virtual const access_traits& 90 get_access_traits() const = 0; 91 92 private: 93 typedef typename access_traits::const_iterator e_const_iterator; 94 typedef std::pair<e_const_iterator, e_const_iterator> prefix_range_t; 95 96 protected: 97 static size_type 98 common_prefix_len(node_iterator, e_const_iterator, 99 e_const_iterator, const access_traits&); 100 101 static iterator 102 leftmost_it(node_iterator); 103 104 static iterator 105 rightmost_it(node_iterator); 106 107 static bool 108 less(e_const_iterator, e_const_iterator, e_const_iterator, 109 e_const_iterator, const access_traits&); 110 }; 111 112 113 #define PB_DS_CLASS_T_DEC \ 114 template<typename Node_CItr, typename Node_Itr, \ 115 typename _ATraits, typename _Alloc> 116 117 #define PB_DS_CLASS_C_DEC \ 118 trie_policy_base<Node_CItr, Node_Itr, _ATraits, _Alloc> 119 120 PB_DS_CLASS_T_DEC 121 typename PB_DS_CLASS_C_DEC::size_type 122 PB_DS_CLASS_C_DEC:: 123 common_prefix_len(node_iterator nd_it, e_const_iterator b_r, 124 e_const_iterator e_r, const access_traits& r_traits) 125 { 126 prefix_range_t pref_range = nd_it.valid_prefix(); 127 128 e_const_iterator b_l = pref_range.first; 129 e_const_iterator e_l = pref_range.second; 130 131 const size_type range_length_l = std::distance(b_l, e_l); 132 const size_type range_length_r = std::distance(b_r, e_r); 133 134 if (range_length_r < range_length_l) 135 { 136 std::swap(b_l, b_r); 137 std::swap(e_l, e_r); 138 } 139 140 size_type ret = 0; 141 while (b_l != e_l) 142 { 143 if (r_traits.e_pos(*b_l) != r_traits.e_pos(*b_r)) 144 return ret; 145 146 ++ret; 147 ++b_l; 148 ++b_r; 149 } 150 151 return ret; 152 } 153 154 PB_DS_CLASS_T_DEC 155 typename PB_DS_CLASS_C_DEC::iterator 156 PB_DS_CLASS_C_DEC:: 157 leftmost_it(node_iterator nd_it) 158 { 159 if (nd_it.num_children() == 0) 160 return *nd_it; 161 162 return leftmost_it(nd_it.get_child(0)); 163 } 164 165 PB_DS_CLASS_T_DEC 166 typename PB_DS_CLASS_C_DEC::iterator 167 PB_DS_CLASS_C_DEC:: 168 rightmost_it(node_iterator nd_it) 169 { 170 const size_type num_children = nd_it.num_children(); 171 172 if (num_children == 0) 173 return *nd_it; 174 175 return rightmost_it(nd_it.get_child(num_children - 1)); 176 } 177 178 PB_DS_CLASS_T_DEC 179 bool 180 PB_DS_CLASS_C_DEC:: 181 less(e_const_iterator b_l, e_const_iterator e_l, 182 e_const_iterator b_r, e_const_iterator e_r, 183 const access_traits& r_traits) 184 { 185 while (b_l != e_l) 186 { 187 if (b_r == e_r) 188 return false; 189 190 size_type l_pos = r_traits.e_pos(*b_l); 191 size_type r_pos = r_traits.e_pos(*b_r); 192 if (l_pos != r_pos) 193 return (l_pos < r_pos); 194 195 ++b_l; 196 ++b_r; 197 } 198 return b_r != e_r; 199 } 200 201 #undef PB_DS_CLASS_T_DEC 202 #undef PB_DS_CLASS_C_DEC 203 204 } // namespace detail 205 } // namespace __gnu_pbds 206 207 #endif // #ifndef PB_DS_TRIE_POLICY_BASE_HPP 208