beedb/include/util/random_generator.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 <array>
#include <cstdint>
namespace beedb::util
{
/**
* Random generator for cheap pseudo random numbers.
*/
class RandomGenerator
{
public:
RandomGenerator() noexcept;
explicit RandomGenerator(std::uint32_t seed) noexcept;
/**
* @return Next pseudo random number.
*/
std::int32_t next() noexcept;
/**
* @param max_value Max value.
* @return Next pseudo random number in range (0,max_value].
*/
std::uint32_t next(const std::uint64_t max_value) noexcept
{
return next() % max_value;
}
private:
std::array<std::uint32_t, 7> _register;
std::uint32_t _multiplier = 0;
std::uint32_t _ic_state = 0;
const std::uint32_t _addend = 0;
};
} // namespace beedb::util