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| Commit | Line | Data |
|---|---|---|
| 4c2d6a70 AC |
1 | ------------------------------------------------------------------------------ |
| 2 | -- -- | |
| 3 | -- GNAT LIBRARY COMPONENTS -- | |
| 4 | -- -- | |
| 3084fecd | 5 | -- 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 -- |
| 4c2d6a70 AC |
6 | -- -- |
| 7 | -- S p e c -- | |
| 8 | -- -- | |
| 4b490c1e | 9 | -- Copyright (C) 2004-2020, Free Software Foundation, Inc. -- |
| 4c2d6a70 | 10 | -- -- |
| d90e94c7 JM |
11 | -- GNAT is free software; you can redistribute it and/or modify it under -- |
| 12 | -- terms of the GNU General Public License as published by the Free Soft- -- | |
| 748086b7 | 13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| d90e94c7 JM |
14 | -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| 15 | -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
| 748086b7 JJ |
16 | -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| 17 | -- -- | |
| 18 | -- As a special exception under Section 7 of GPL version 3, you are granted -- | |
| 19 | -- additional permissions described in the GCC Runtime Library Exception, -- | |
| 20 | -- version 3.1, as published by the Free Software Foundation. -- | |
| 21 | -- -- | |
| 22 | -- You should have received a copy of the GNU General Public License and -- | |
| 23 | -- a copy of the GCC Runtime Library Exception along with this program; -- | |
| 24 | -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- | |
| 25 | -- <http://www.gnu.org/licenses/>. -- | |
| d90e94c7 JM |
26 | -- -- |
| 27 | -- This unit was originally developed by Matthew J Heaney. -- | |
| 4c2d6a70 AC |
28 | ------------------------------------------------------------------------------ |
| 29 | ||
| d90e94c7 JM |
30 | -- This package declares the prime numbers array used to implement hashed |
| 31 | -- containers. Bucket arrays are always allocated with a prime-number | |
| 32 | -- length (computed using To_Prime below), as this produces better scatter | |
| 33 | -- when hash values are folded. | |
| 34 | ||
| 4c2d6a70 | 35 | package Ada.Containers.Prime_Numbers is |
| 009186e0 | 36 | pragma Pure; |
| 4c2d6a70 AC |
37 | |
| 38 | type Primes_Type is array (Positive range <>) of Hash_Type; | |
| 39 | ||
| 40 | Primes : constant Primes_Type := | |
| 41 | (53, 97, 193, 389, 769, | |
| 42 | 1543, 3079, 6151, 12289, 24593, | |
| 43 | 49157, 98317, 196613, 393241, 786433, | |
| 44 | 1572869, 3145739, 6291469, 12582917, 25165843, | |
| 45 | 50331653, 100663319, 201326611, 402653189, 805306457, | |
| 46 | 1610612741, 3221225473, 4294967291); | |
| 47 | ||
| 48 | function To_Prime (Length : Count_Type) return Hash_Type; | |
| d90e94c7 | 49 | -- Returns the smallest value in Primes not less than Length |
| 4c2d6a70 AC |
50 | |
| 51 | end Ada.Containers.Prime_Numbers; |