// -*- C++ -*-
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// Copyright (C) 2005-2017 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the terms
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// of the GNU General Public License as published by the Free Software
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// Foundation; either version 3, or (at your option) any later
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// version.
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
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// Permission to use, copy, modify, sell, and distribute this software
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// is hereby granted without fee, provided that the above copyright
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// notice appears in all copies, and that both that copyright notice
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// and this permission notice appear in supporting documentation. None
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// of the above authors, nor IBM Haifa Research Laboratories, make any
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// representation about the suitability of this software for any
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// purpose. It is provided "as is" without express or implied
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// warranty.
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/**
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* @file trie_policy/trie_policy_base.hpp
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* Contains an implementation of trie_policy_base.
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*/
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#ifndef PB_DS_TRIE_POLICY_BASE_HPP
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#define PB_DS_TRIE_POLICY_BASE_HPP
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#include <ext/pb_ds/detail/branch_policy/branch_policy.hpp>
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namespace __gnu_pbds
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{
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namespace detail
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{
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/// Base class for trie policies.
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template<typename Node_CItr, typename Node_Itr,
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typename _ATraits, typename _Alloc>
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class trie_policy_base
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: public branch_policy<Node_CItr, Node_Itr, _Alloc>
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{
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typedef branch_policy<Node_CItr, Node_Itr, _Alloc> base_type;
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public:
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typedef _ATraits access_traits;
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typedef _Alloc allocator_type;
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typedef typename allocator_type::size_type size_type;
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typedef null_type metadata_type;
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typedef Node_CItr node_const_iterator;
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typedef Node_Itr node_iterator;
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typedef typename node_const_iterator::value_type const_iterator;
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typedef typename node_iterator::value_type iterator;
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typedef typename base_type::key_type key_type;
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typedef typename base_type::key_const_reference key_const_reference;
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protected:
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virtual const_iterator
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end() const = 0;
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virtual iterator
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end() = 0;
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virtual node_const_iterator
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node_begin() const = 0;
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virtual node_iterator
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node_begin() = 0;
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virtual node_const_iterator
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node_end() const = 0;
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virtual node_iterator
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node_end() = 0;
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virtual const access_traits&
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get_access_traits() const = 0;
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private:
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typedef typename access_traits::const_iterator e_const_iterator;
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typedef std::pair<e_const_iterator, e_const_iterator> prefix_range_t;
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protected:
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static size_type
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common_prefix_len(node_iterator, e_const_iterator,
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e_const_iterator, const access_traits&);
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static iterator
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leftmost_it(node_iterator);
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static iterator
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rightmost_it(node_iterator);
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static bool
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less(e_const_iterator, e_const_iterator, e_const_iterator,
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e_const_iterator, const access_traits&);
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};
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#define PB_DS_CLASS_T_DEC \
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template<typename Node_CItr, typename Node_Itr, \
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typename _ATraits, typename _Alloc>
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#define PB_DS_CLASS_C_DEC \
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trie_policy_base<Node_CItr, Node_Itr, _ATraits, _Alloc>
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PB_DS_CLASS_T_DEC
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typename PB_DS_CLASS_C_DEC::size_type
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PB_DS_CLASS_C_DEC::
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common_prefix_len(node_iterator nd_it, e_const_iterator b_r,
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e_const_iterator e_r, const access_traits& r_traits)
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{
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prefix_range_t pref_range = nd_it.valid_prefix();
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e_const_iterator b_l = pref_range.first;
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e_const_iterator e_l = pref_range.second;
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const size_type range_length_l = std::distance(b_l, e_l);
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const size_type range_length_r = std::distance(b_r, e_r);
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if (range_length_r < range_length_l)
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{
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std::swap(b_l, b_r);
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std::swap(e_l, e_r);
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}
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size_type ret = 0;
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while (b_l != e_l)
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{
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if (r_traits.e_pos(*b_l) != r_traits.e_pos(*b_r))
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return ret;
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++ret;
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++b_l;
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++b_r;
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}
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return ret;
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}
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PB_DS_CLASS_T_DEC
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typename PB_DS_CLASS_C_DEC::iterator
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PB_DS_CLASS_C_DEC::
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leftmost_it(node_iterator nd_it)
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{
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if (nd_it.num_children() == 0)
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return *nd_it;
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return leftmost_it(nd_it.get_child(0));
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}
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PB_DS_CLASS_T_DEC
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typename PB_DS_CLASS_C_DEC::iterator
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PB_DS_CLASS_C_DEC::
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rightmost_it(node_iterator nd_it)
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{
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const size_type num_children = nd_it.num_children();
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if (num_children == 0)
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return *nd_it;
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return rightmost_it(nd_it.get_child(num_children - 1));
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}
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PB_DS_CLASS_T_DEC
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bool
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PB_DS_CLASS_C_DEC::
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less(e_const_iterator b_l, e_const_iterator e_l,
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e_const_iterator b_r, e_const_iterator e_r,
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const access_traits& r_traits)
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{
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while (b_l != e_l)
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{
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if (b_r == e_r)
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return false;
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size_type l_pos = r_traits.e_pos(*b_l);
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size_type r_pos = r_traits.e_pos(*b_r);
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if (l_pos != r_pos)
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return (l_pos < r_pos);
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++b_l;
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++b_r;
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}
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return b_r != e_r;
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}
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#undef PB_DS_CLASS_T_DEC
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#undef PB_DS_CLASS_C_DEC
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} // namespace detail
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} // namespace __gnu_pbds
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#endif // #ifndef PB_DS_TRIE_POLICY_BASE_HPP
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