xref: /freebsd-9.3-release/contrib/libstdc++/include/ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp

// -*- C++ -*-

// Copyright (C) 2005, 2006 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 2, 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.

// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING.  If not, write to
// the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
// MA 02111-1307, USA.

// As a special exception, you may use this file as part of a free
// software library without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to
// produce an executable, this file does not by itself cause the
// resulting executable to be covered by the GNU General Public
// License.  This exception does not however invalidate any other
// reasons why the executable file might be covered by the GNU General
// Public License.

// 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 prefix_search_node_update_imp.hpp
 * Contains an implementation of prefix_search_node_update.
 */

PB_DS_CLASS_T_DEC
std::pair<
  typename PB_DS_CLASS_C_DEC::const_iterator,
  typename PB_DS_CLASS_C_DEC::const_iterator>
PB_DS_CLASS_C_DEC::
prefix_range(const_key_reference r_key) const
{
  const e_access_traits& r_traits = get_e_access_traits();

  return (prefix_range(
		       r_traits.begin(r_key),
		       r_traits.end(r_key)));
}

PB_DS_CLASS_T_DEC
std::pair<
  typename PB_DS_CLASS_C_DEC::iterator,
  typename PB_DS_CLASS_C_DEC::iterator>
PB_DS_CLASS_C_DEC::
prefix_range(const_key_reference r_key)
{
  return (prefix_range(
		       get_e_access_traits().begin(r_key),
		       get_e_access_traits().end(r_key)));
}

PB_DS_CLASS_T_DEC
std::pair<
  typename PB_DS_CLASS_C_DEC::const_iterator,
  typename PB_DS_CLASS_C_DEC::const_iterator>
PB_DS_CLASS_C_DEC::
prefix_range(typename e_access_traits::const_iterator b, typename e_access_traits::const_iterator e) const
{
  const std::pair<iterator, iterator> non_const_ret =
    const_cast<PB_DS_CLASS_C_DEC* >(this)->prefix_range(b, e);

  return (std::make_pair(
			 const_iterator(non_const_ret.first),
			 const_iterator(non_const_ret.second)));
}

PB_DS_CLASS_T_DEC
std::pair<
  typename PB_DS_CLASS_C_DEC::iterator,
  typename PB_DS_CLASS_C_DEC::iterator>
PB_DS_CLASS_C_DEC::
prefix_range(typename e_access_traits::const_iterator b, typename e_access_traits::const_iterator e)
{
  Node_Iterator nd_it = node_begin();
  Node_Iterator end_nd_it = node_end();

  const e_access_traits& r_traits =
    get_e_access_traits();

  const size_type given_range_length = std::distance(b, e);

  while (true)
    {
      if (nd_it == end_nd_it)
	return (std::make_pair(end(), end()));

      const size_type common_range_length =
	PB_DS_BASE_C_DEC::common_prefix_len(nd_it, b, e, r_traits);

      if (common_range_length >= given_range_length)
        {
	  iterator ret_b = leftmost_it(nd_it);

	  iterator ret_e = rightmost_it(nd_it);

	  return (std::make_pair(ret_b, ++ret_e));
        }

      nd_it = next_child(nd_it, b, e, end_nd_it, r_traits);
    }
}

PB_DS_CLASS_T_DEC
typename PB_DS_CLASS_C_DEC::node_iterator
PB_DS_CLASS_C_DEC::
next_child(node_iterator nd_it, typename e_access_traits::const_iterator b, typename e_access_traits::const_iterator e, node_iterator end_nd_it, const e_access_traits& r_traits)
{
  const size_type num_children = nd_it.num_children();

  node_iterator ret = end_nd_it;

  size_type max_length = 0;

  for (size_type i = 0; i < num_children; ++i)
    {
      node_iterator pot = nd_it.get_child(i);

      const size_type common_range_length =
	PB_DS_BASE_C_DEC::common_prefix_len(            pot, b, e, r_traits);

      if (common_range_length > max_length)
        {
	  ret = pot;

	  max_length = common_range_length;
        }
    }

  return (ret);
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
operator()(node_iterator /*nd_it*/, const_node_iterator /*end_nd_it*/) const
{ }