utility/PrimeNumber.hpp

/**
 *   Copyright 2011-2015 Quickstep Technologies LLC.
 *   Copyright 2015 Pivotal Software, Inc.
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 **/

#ifndef QUICKSTEP_UTILITY_PRIME_NUMBER_HPP_
#define QUICKSTEP_UTILITY_PRIME_NUMBER_HPP_

#include <cstddef>

namespace quickstep {

/** \addtogroup Utility
 *  @{
 */

/**
 * @brief Find the least prime number that is greater than or equal to the
 *        argument.
 *
 * @param number The number to compute.
 * @return The least prime number greater than or equal to the input number.
 **/
std::size_t get_next_prime_number(std::size_t number);

/**
 * @brief Find the greatest prime number that is less than or equal to the
 *        argument.
 *
 * @param number The number to compute.
 * @return The greatest prime number less than or equal the input number, or 0
 *         if no such prime exists (i.e. if the input is 0 or 1).
 **/
std::size_t get_previous_prime_number(std::size_t number);

/** @} */

}  // namespace quickstep

#endif  // QUICKSTEP_UTILITY_PRIME_NUMBER_HPP_