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+------------------------------------------------------------------------------
+-- --
+-- 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) 2004-2009, 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;