libstdc++-v3/include/ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2022 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/prefix_search_node_update_imp.hpp
  38  * Contains an implementation of prefix_search_node_update.
  39  */
  40
  41 #ifdef PB_DS_CLASS_C_DEC
  42
  43 PB_DS_CLASS_T_DEC
  44 std::pair<
  45   typename PB_DS_CLASS_C_DEC::const_iterator,
  46   typename PB_DS_CLASS_C_DEC::const_iterator>
  47 PB_DS_CLASS_C_DEC::
  48 prefix_range(key_const_reference r_key) const
  49 {
  50   const access_traits& r_traits = get_access_traits();
  51   return (prefix_range(r_traits.begin(r_key), r_traits.end(r_key)));
  52 }
  53
  54 PB_DS_CLASS_T_DEC
  55 std::pair<
  56   typename PB_DS_CLASS_C_DEC::iterator,
  57   typename PB_DS_CLASS_C_DEC::iterator>
  58 PB_DS_CLASS_C_DEC::
  59 prefix_range(key_const_reference r_key)
  60 {
  61   return (prefix_range(get_access_traits().begin(r_key),
  62                        get_access_traits().end(r_key)));
  63 }
  64
  65 PB_DS_CLASS_T_DEC
  66 std::pair<
  67   typename PB_DS_CLASS_C_DEC::const_iterator,
  68   typename PB_DS_CLASS_C_DEC::const_iterator>
  69 PB_DS_CLASS_C_DEC::
  70 prefix_range(typename access_traits::const_iterator b,
  71              typename access_traits::const_iterator e) const
  72 {
  73   const std::pair<iterator, iterator> non_const_ret =
  74     const_cast<PB_DS_CLASS_C_DEC* >(this)->prefix_range(b, e);
  75
  76   return (std::make_pair(const_iterator(non_const_ret.first),
  77                          const_iterator(non_const_ret.second)));
  78 }
  79
  80 PB_DS_CLASS_T_DEC
  81 std::pair<
  82   typename PB_DS_CLASS_C_DEC::iterator,
  83   typename PB_DS_CLASS_C_DEC::iterator>
  84 PB_DS_CLASS_C_DEC::
  85 prefix_range(typename access_traits::const_iterator b,
  86              typename access_traits::const_iterator e)
  87 {
  88   Node_Itr nd_it = node_begin();
  89   Node_Itr end_nd_it = node_end();
  90
  91   const access_traits& r_traits = get_access_traits();
  92   const size_type given_range_length = std::distance(b, e);
  93
  94   while (true)
  95     {
  96       if (nd_it == end_nd_it)
  97         return (std::make_pair(end(), end()));
  98
  99       const size_type common_range_length =
 100         base_type::common_prefix_len(nd_it, b, e, r_traits);
 101
 102       if (common_range_length >= given_range_length)
 103         {
 104           iterator ret_b = this->leftmost_it(nd_it);
 105           iterator ret_e = this->rightmost_it(nd_it);
 106           return (std::make_pair(ret_b, ++ret_e));
 107         }
 108       nd_it = next_child(nd_it, b, e, end_nd_it, r_traits);
 109     }
 110 }
 111
 112 PB_DS_CLASS_T_DEC
 113 typename PB_DS_CLASS_C_DEC::node_iterator
 114 PB_DS_CLASS_C_DEC::
 115 next_child(node_iterator nd_it, typename access_traits::const_iterator b,
 116            typename access_traits::const_iterator e, node_iterator end_nd_it,
 117            const access_traits& r_traits)
 118 {
 119   const size_type num_children = nd_it.num_children();
 120   node_iterator ret = end_nd_it;
 121   size_type max_length = 0;
 122   for (size_type i = 0; i < num_children; ++i)
 123     {
 124       node_iterator pot = nd_it.get_child(i);
 125       const size_type common_range_length =
 126         base_type::common_prefix_len(pot, b, e, r_traits);
 127
 128       if (common_range_length > max_length)
 129         {
 130           ret = pot;
 131           max_length = common_range_length;
 132         }
 133     }
 134   return (ret);
 135 }
 136
 137 PB_DS_CLASS_T_DEC
 138 inline void
 139 PB_DS_CLASS_C_DEC::
 140 operator()(node_iterator /*nd_it*/, node_const_iterator /*end_nd_it*/) const
 141 { }
 142 #endif