/*
  Copyright(C) 2011-2016 Brazil

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#pragma once

#include "dat.hpp"

namespace grn {
namespace dat {

// The most significant bit represents whether or not the node is a linker.
// BASE of a linker represents the position of its associated key and BASE of
// a non-linker represents the offset to its child nodes.
class GRN_DAT_API Base {
 public:
  Base() : value_(0) {}

  bool operator==(const Base &rhs) const {
    return value_ == rhs.value_;
  }

  bool is_linker() const {
    return (value_ & IS_LINKER_FLAG) == IS_LINKER_FLAG;
  }
  UInt32 offset() const {
    GRN_DAT_DEBUG_THROW_IF(is_linker());
    return value_;
  }
  UInt32 key_pos() const {
    GRN_DAT_DEBUG_THROW_IF(!is_linker());
    return value_ & ~IS_LINKER_FLAG;
  }

  void set_offset(UInt32 x) {
    GRN_DAT_DEBUG_THROW_IF((x & IS_LINKER_FLAG) != 0);
    GRN_DAT_DEBUG_THROW_IF(x > MAX_OFFSET);
    value_ = x;
  }
  void set_key_pos(UInt32 x) {
    GRN_DAT_DEBUG_THROW_IF((x & IS_LINKER_FLAG) != 0);
    GRN_DAT_DEBUG_THROW_IF(x > MAX_OFFSET);
    value_ = IS_LINKER_FLAG | x;
  }

 private:
  UInt32 value_;

  static const UInt32 IS_LINKER_FLAG = 0x80000000U;
};

}  // namespace dat
}  // namespace grn
