--- /dev/null
+// -*- C++ -*-
+
+// Copyright (C) 2005, 2006, 2009 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 3, 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
+
+// Permission to use, copy, modify, sell, and distribute this software
+// is hereby granted without fee, provided that the above copyright
+// notice appears in all copies, and that both that copyright notice
+// and this permission notice appear in supporting documentation. None
+// of the above authors, nor IBM Haifa Research Laboratories, make any
+// representation about the suitability of this software for any
+// purpose. It is provided "as is" without express or implied
+// warranty.
+
+/**
+ * @file trie_policy/trie_policy_base.hpp
+ * Contains an implementation of trie_policy_base.
+ */
+
+#ifndef PB_DS_TRIE_POLICY_BASE_HPP
+#define PB_DS_TRIE_POLICY_BASE_HPP
+
+#include <ext/pb_ds/detail/branch_policy/branch_policy.hpp>
+
+namespace __gnu_pbds
+{
+ namespace detail
+ {
+ /// Base class for trie policies.
+ template<typename Node_CItr, typename Node_Itr,
+ typename _ATraits, typename _Alloc>
+ class trie_policy_base
+ : public branch_policy<Node_CItr, Node_Itr, _Alloc>
+ {
+ typedef branch_policy<Node_CItr, Node_Itr, _Alloc> base_type;
+
+ public:
+ typedef _ATraits access_traits;
+ typedef _Alloc allocator_type;
+ typedef typename allocator_type::size_type size_type;
+ typedef null_type metadata_type;
+ typedef Node_CItr node_const_iterator;
+ typedef Node_Itr node_iterator;
+ typedef typename node_const_iterator::value_type const_iterator;
+ typedef typename node_iterator::value_type iterator;
+ typedef typename base_type::key_type key_type;
+ typedef typename base_type::key_const_reference key_const_reference;
+
+ protected:
+ virtual const_iterator
+ end() const = 0;
+
+ virtual iterator
+ end() = 0;
+
+ virtual node_const_iterator
+ node_begin() const = 0;
+
+ virtual node_iterator
+ node_begin() = 0;
+
+ virtual node_const_iterator
+ node_end() const = 0;
+
+ virtual node_iterator
+ node_end() = 0;
+
+ virtual const access_traits&
+ get_access_traits() const = 0;
+
+ private:
+ typedef typename access_traits::const_iterator e_const_iterator;
+ typedef std::pair<e_const_iterator, e_const_iterator> prefix_range_t;
+
+ protected:
+ static size_type
+ common_prefix_len(node_iterator, e_const_iterator,
+ e_const_iterator, const access_traits&);
+
+ static iterator
+ leftmost_it(node_iterator);
+
+ static iterator
+ rightmost_it(node_iterator);
+
+ static bool
+ less(e_const_iterator, e_const_iterator, e_const_iterator,
+ e_const_iterator, const access_traits&);
+ };
+
+
+#define PB_DS_CLASS_T_DEC \
+ template<typename Node_CItr, typename Node_Itr, \
+ typename _ATraits, typename _Alloc>
+
+#define PB_DS_CLASS_C_DEC \
+ trie_policy_base<Node_CItr, Node_Itr, _ATraits, _Alloc>
+
+ PB_DS_CLASS_T_DEC
+ typename PB_DS_CLASS_C_DEC::size_type
+ PB_DS_CLASS_C_DEC::
+ common_prefix_len(node_iterator nd_it, e_const_iterator b_r,
+ e_const_iterator e_r, const access_traits& r_traits)
+ {
+ prefix_range_t pref_range = nd_it.valid_prefix();
+
+ e_const_iterator b_l = pref_range.first;
+ e_const_iterator e_l = pref_range.second;
+
+ const size_type range_length_l = std::distance(b_l, e_l);
+ const size_type range_length_r = std::distance(b_r, e_r);
+
+ if (range_length_r < range_length_l)
+ {
+ std::swap(b_l, b_r);
+ std::swap(e_l, e_r);
+ }
+
+ size_type ret = 0;
+ while (b_l != e_l)
+ {
+ if (r_traits.e_pos(*b_l) != r_traits.e_pos(*b_r))
+ return ret;
+
+ ++ret;
+ ++b_l;
+ ++b_r;
+ }
+
+ return ret;
+ }
+
+ PB_DS_CLASS_T_DEC
+ typename PB_DS_CLASS_C_DEC::iterator
+ PB_DS_CLASS_C_DEC::
+ leftmost_it(node_iterator nd_it)
+ {
+ if (nd_it.num_children() == 0)
+ return *nd_it;
+
+ return leftmost_it(nd_it.get_child(0));
+ }
+
+ PB_DS_CLASS_T_DEC
+ typename PB_DS_CLASS_C_DEC::iterator
+ PB_DS_CLASS_C_DEC::
+ rightmost_it(node_iterator nd_it)
+ {
+ const size_type num_children = nd_it.num_children();
+
+ if (num_children == 0)
+ return *nd_it;
+
+ return rightmost_it(nd_it.get_child(num_children - 1));
+ }
+
+ PB_DS_CLASS_T_DEC
+ bool
+ PB_DS_CLASS_C_DEC::
+ less(e_const_iterator b_l, e_const_iterator e_l,
+ e_const_iterator b_r, e_const_iterator e_r,
+ const access_traits& r_traits)
+ {
+ while (b_l != e_l)
+ {
+ if (b_r == e_r)
+ return false;
+
+ size_type l_pos = r_traits.e_pos(*b_l);
+ size_type r_pos = r_traits.e_pos(*b_r);
+ if (l_pos != r_pos)
+ return (l_pos < r_pos);
+
+ ++b_l;
+ ++b_r;
+ }
+ return b_r != e_r;
+ }
+
+#undef PB_DS_CLASS_T_DEC
+#undef PB_DS_CLASS_C_DEC
+
+ } // namespace detail
+} // namespace __gnu_pbds
+
+#endif // #ifndef PB_DS_TRIE_POLICY_BASE_HPP
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