| ------------------------------------------------------------------------------ |

| -- -- |

| -- GNAT LIBRARY COMPONENTS -- |

| -- -- |

| -- A D A . C O N T A I N E R S . P R I M E _ N U M B E R S -- |

| -- -- |

| -- S p e c -- |

| -- -- |

| -- Copyright (C) 2004-2021, Free Software Foundation, Inc. -- |

| -- -- |

| -- GNAT is free software; you can redistribute it and/or modify it under -- |

| -- terms of the GNU General Public License as published by the Free Soft- -- |

| -- ware Foundation; either version 3, or (at your option) any later ver- -- |

| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |

| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |

| -- or FITNESS FOR A PARTICULAR PURPOSE. -- |

| -- -- |

| -- As a special exception under Section 7 of GPL version 3, you are granted -- |

| -- additional permissions described in the GCC Runtime Library Exception, -- |

| -- version 3.1, as published by the Free Software Foundation. -- |

| -- -- |

| -- You should have received a copy of the GNU General Public License and -- |

| -- a copy of the GCC Runtime Library Exception along with this program; -- |

| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |

| -- <http://www.gnu.org/licenses/>. -- |

| -- -- |

| -- This unit was originally developed by Matthew J Heaney. -- |

| ------------------------------------------------------------------------------ |

| |

| -- This package declares the prime numbers array used to implement hashed |

| -- containers. Bucket arrays are always allocated with a prime-number |

| -- length (computed using To_Prime below), as this produces better scatter |

| -- when hash values are folded. |

| |

| package Ada.Containers.Prime_Numbers is |

| pragma Pure; |

| |

| type Primes_Type is array (Positive range <>) of Hash_Type; |

| |

| Primes : constant Primes_Type := |

| (53, 97, 193, 389, 769, |

| 1543, 3079, 6151, 12289, 24593, |

| 49157, 98317, 196613, 393241, 786433, |

| 1572869, 3145739, 6291469, 12582917, 25165843, |

| 50331653, 100663319, 201326611, 402653189, 805306457, |

| 1610612741, 3221225473, 4294967291); |

| |

| function To_Prime (Length : Count_Type) return Hash_Type; |

| -- Returns the smallest value in Primes not less than Length |

| |

| end Ada.Containers.Prime_Numbers; |