snapshot_id.hpp

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/*
 * Copyright (c) 2014-2015, Hewlett-Packard Development Company, LP.
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * HP designates this particular file as subject to the "Classpath" exception
 * as provided by HP in the LICENSE.txt file that accompanied this code.
 */
#ifndef FOEDUS_SNAPSHOT_SNAPSHOT_ID_HPP_
#define FOEDUS_SNAPSHOT_SNAPSHOT_ID_HPP_
#include <stdint.h>

#include "foedus/assert_nd.hpp"

namespace foedus {
namespace snapshot {
typedef uint16_t SnapshotId;

const SnapshotId kNullSnapshotId = 0;

inline SnapshotId increment(SnapshotId id) {
  ASSERT_ND(id != kNullSnapshotId);
  ++id;
  if (id == kNullSnapshotId) {
    return 1;  // wrap around, and skip 0.
  } else {
    return id;
  }
}

typedef uint32_t BufferPosition;

inline BufferPosition to_buffer_position(uint64_t byte_position) {
  ASSERT_ND(byte_position % 8 == 0);
  return byte_position >> 3;
}
inline uint64_t from_buffer_position(BufferPosition buffer_position) {
  return static_cast<uint64_t>(buffer_position) << 3;
}
}  // namespace snapshot
}  // namespace foedus
#endif  // FOEDUS_SNAPSHOT_SNAPSHOT_ID_HPP_