------------------------------------------------------------------------------
--                                                                          --
--                         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          --
--                                                                          --
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--          Copyright (C) 2004-2006, Free Software Foundation, Inc.         --
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-- GNAT is free software;  you can  redistribute it  and/or modify it under --
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-- for  more details.  You should have  received  a copy of the GNU General --
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-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
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--                                                                          --
-- 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;