beedb/include/storage/record_identifier.h

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2022-04-04 20:25:01 +02:00
/*------------------------------------------------------------------------------*
* Architecture & Implementation of DBMS *
*------------------------------------------------------------------------------*
* Copyright 2022 Databases and Information Systems Group TU Dortmund *
* Visit us at *
* http://dbis.cs.tu-dortmund.de/cms/en/home/ *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR *
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
* OTHER DEALINGS IN THE SOFTWARE. *
* *
* Authors: *
* Maximilian Berens <maximilian.berens@tu-dortmund.de> *
* Roland Kühn <roland.kuehn@cs.tu-dortmund.de> *
* Jan Mühlig <jan.muehlig@tu-dortmund.de> *
*------------------------------------------------------------------------------*
*/
#pragma once
#include "page.h"
namespace beedb::storage
{
class alignas(64) RecordIdentifier
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{
public:
static_assert(sizeof(Page::id_t) + sizeof(std::uint16_t) <= sizeof(std::uint64_t));
RecordIdentifier() = default;
RecordIdentifier(const RecordIdentifier &) = default;
RecordIdentifier(Page::id_t page_id, std::uint16_t slot)
{
this->page_id(page_id);
this->slot(slot);
}
~RecordIdentifier() = default;
[[nodiscard]] Page::id_t page_id() const
{
return _identifier >> (sizeof(std::uint16_t) * 8);
}
[[nodiscard]] std::uint16_t slot() const
{
return _identifier & std::numeric_limits<std::uint16_t>::max();
}
void page_id(Page::id_t page_id)
{
_identifier = (std::uint64_t(page_id) << (sizeof(Page::offset_t) * 8) | std::uint64_t(this->slot()));
}
void slot(const Page::offset_t offset)
{
_identifier = (std::uint64_t(this->page_id()) << (sizeof(std::uint16_t) * 8)) | offset;
}
explicit operator bool() const
{
return _identifier < std::numeric_limits<decltype(_identifier)>::max();
}
explicit operator std::uint64_t() const
{
return _identifier;
}
bool operator==(const RecordIdentifier other) const
{
return _identifier == other._identifier;
}
private:
std::uint64_t _identifier = std::numeric_limits<decltype(_identifier)>::max();
};
} // namespace beedb::storage
namespace std
{
template <> struct hash<beedb::storage::RecordIdentifier>
{
public:
std::size_t operator()(const beedb::storage::RecordIdentifier &rid) const
{
return std::hash<std::uint64_t>()(static_cast<std::uint64_t>(rid));
}
};
} // namespace std