hash_metadata.cpp

Go to the documentation of this file.

/*
 * 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.
 */
#include "foedus/storage/hash/hash_metadata.hpp"

#include <iostream>
#include <sstream>
#include <string>

#include "foedus/externalize/externalizable.hpp"

namespace foedus {
namespace storage {
namespace hash {
std::string HashMetadata::describe() const {
  std::stringstream o;
  o << HashMetadataSerializer(const_cast<HashMetadata*>(this));
  return o.str();
}
std::ostream& operator<<(std::ostream& o, const HashMetadata& v) {
  o << HashMetadataSerializer(const_cast<HashMetadata*>(&v));
  return o;
}

ErrorStack HashMetadataSerializer::load(tinyxml2::XMLElement* element) {
  CHECK_ERROR(load_base(element));
  CHECK_ERROR(get_element(element, "bin_bits_", &data_casted_->bin_bits_))
  return kRetOk;
}

ErrorStack HashMetadataSerializer::save(tinyxml2::XMLElement* element) const {
  CHECK_ERROR(save_base(element));
  CHECK_ERROR(add_element(element, "bin_bits_", "", data_casted_->bin_bits_));
  return kRetOk;
}

void HashMetadata::set_capacity(uint64_t expected_records, double preferred_records_per_bin) {
  if (expected_records == 0) {
    expected_records = 1;
  }
  if (preferred_records_per_bin < 1) {
    preferred_records_per_bin = 1;
  }
  uint64_t bin_count = expected_records / preferred_records_per_bin;
  uint8_t bits;
  for (bits = 0; bits < kHashMaxBinBits && ((1ULL << bits) < bin_count); ++bits) {
    continue;
  }
  if (bits < kHashMinBinBits) {
    bits = kHashMinBinBits;
  }
  bin_bits_ = bits;
  ASSERT_ND(bin_bits_ >= kHashMinBinBits);
  ASSERT_ND(bin_bits_ <= kHashMaxBinBits);
}


}  // namespace hash
}  // namespace storage
}  // namespace foedus