marked_pointer.hh

// This file is a part of Aurelia.
// Copyright (C) 2010  Valentin David
// Copyright (C) 2010  University of Bergen
//
// This program 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 of the License, or
// (at your option) any later version.
//
// This program 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 program.  If not, see <http://www.gnu.org/licenses/>.

#ifndef __MARKED_POINTER_HH
# define __MARKED_POINTER_HH

# include <type_traits>
# include <memory>

namespace lockfree {
  namespace details {
    template <typename T>
    void assert_align() {
      static_assert(std::alignment_of<T>::value != 1,
                    "Pointer cannot be marked as its alignment is 1");
    }

    template <typename T>
    bool is_marked(T* p) {
      assert_align<T>();
      return 0x1 & (size_t)p;
    };

    template <typename T>
    T* unmarked(T* p) {
      assert_align<T>();
      return (T*)((~0x1) & (size_t)p);
    };

    template <typename T>
    T* marked(T* p) {
      assert_align<T>();
      return (T*)(0x1 | (size_t)p);
    };
  }
}

#endif