branch_policy.hpp

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// -*- C++ -*-
 
// Copyright (C) 2005-2021 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 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>
#include <ext/pb_ds/detail/types_traits.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 rebind_traits<_Alloc, rcvalue_type>     rebind_v;
        typedef rebind_traits<_Alloc, rckey_type>       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 rebind_traits<_Alloc, rcvalue_type>     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