OCCT

// Copyright (c) 2024 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _NCollection_Primes_HeaderFile
#define _NCollection_Primes_HeaderFile

#include <Standard_Macro.hxx>

#include <cstddef>

//! Namespace provides a collection of prime numbers.
//!
//! This namespace is used to store a collection of prime numbers that are used as
//! consecutive steps for the size of an array of buckets in a map. The prime
//! numbers are chosen to minimize the probability of having the same hash codes
//! for different map items. The namespace also provides a method to find the next
//! prime number greater than or equal to a given number.
//!
//! The following are Pierpont primes, prime numbers of the form 2^u * 3^v + 1:
//! 101, 1009, 2003, 5003, 10007, 20011, 37003, 57037, 65003, 100019, 209953, 472393,
//! 995329, 2359297, 4478977, 9437185, 17915905, 35831809, 71663617, 150994945,
//! 301989889, 573308929, 1019215873, 2038431745
namespace NCollection_Primes
{
//! Returns the next prime number greater than or equal to theN.
//! If theN exceeds the largest available prime, returns theN + 1.
Standard_EXPORT size_t NextPrimeForMap(const size_t theN) noexcept;
}; // namespace NCollection_Primes

#endif // _NCollection_Primes_HeaderFile