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[EDIT] FILE: branch_policy.hpp

// -*- C++ -*-

// Copyright (C) 2005-2018 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/>.

// 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
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// warranty.

/**
 * @file branch_policy/branch_policy.hpp
 * Contains a base class for branch policies.
 */

#ifndef PB_DS_BRANCH_POLICY_BASE_HPP
#define PB_DS_BRANCH_POLICY_BASE_HPP

#include <ext/pb_ds/tag_and_trait.hpp>

namespace __gnu_pbds
{
  namespace detail
  {
    /// Primary template, base class for branch structure policies.
    template<typename Node_CItr, typename Node_Itr, typename _Alloc>
      struct branch_policy
      {
      protected:
	typedef typename Node_Itr::value_type 		it_type;
	typedef typename std::iterator_traits<it_type>::value_type value_type;
	typedef typename value_type::first_type 	key_type;

typedef typename remove_const<value_type>::type	rcvalue_type;
	typedef typename remove_const<key_type>::type	rckey_type;

typedef typename _Alloc::template rebind<rcvalue_type>::other rebind_v;
	typedef typename _Alloc::template rebind<rckey_type>::other   rebind_k;

typedef	typename rebind_v::reference 		reference;
	typedef	typename rebind_v::const_reference 	const_reference;
	typedef	typename rebind_v::const_pointer	const_pointer;

typedef	typename rebind_k::const_reference 	key_const_reference;

static inline key_const_reference
	extract_key(const_reference r_val)
	{ return r_val.first; }

virtual it_type
	end() = 0;

it_type
	end_iterator() const
	{ return const_cast<branch_policy*>(this)->end(); }

virtual
	~branch_policy() { }
      };

/// Specialization for const iterators.
    template<typename Node_CItr, typename _Alloc>
      struct branch_policy<Node_CItr, Node_CItr, _Alloc>
      {
      protected:
	typedef typename Node_CItr::value_type 		   it_type;
       	typedef typename std::iterator_traits<it_type>::value_type value_type;
	typedef typename remove_const<value_type>::type		   rcvalue_type;
	typedef typename _Alloc::template rebind<rcvalue_type>::other rebind_v;
	typedef	typename rebind_v::reference 		reference;
	typedef	typename rebind_v::const_reference 	const_reference;
	typedef	typename rebind_v::const_pointer	const_pointer;

typedef value_type 				key_type;
	typedef	typename rebind_v::const_reference 	key_const_reference;

static inline key_const_reference
	extract_key(const_reference r_val)
	{ return r_val; }

virtual it_type
	end() const = 0;

it_type
	end_iterator() const
	{ return end(); }

virtual
	~branch_policy() { }
      };
  } // namespace detail
} // namespace __gnu_pbds

#endif // #ifndef PB_DS_BRANCH_POLICY_BASE_HPP

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