| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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 -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 2004-2005, Free Software Foundation, Inc. -- |
| -- -- |
| -- This specification is derived from the Ada Reference Manual for use with -- |
| -- GNAT. The copyright notice above, and the license provisions that follow -- |
| -- apply solely to the contents of the part following the private keyword. -- |
| -- -- |
| -- 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 2, 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. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNAT; see file COPYING. If not, write -- |
| -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- |
| -- Boston, MA 02110-1301, USA. -- |
| -- -- |
| -- As a special exception, if other files instantiate generics from this -- |
| -- 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 -- |
| -- covered by the GNU General Public License. This exception does not -- |
| -- however invalidate any other reasons why the executable file might be -- |
| -- covered by the GNU Public License. -- |
| -- -- |
| -- This unit was originally developed by Matthew J Heaney. -- |
| ------------------------------------------------------------------------------ |
| |
| package body Ada.Containers.Prime_Numbers is |
| |
| -------------- |
| -- To_Prime -- |
| -------------- |
| |
| function To_Prime (Length : Count_Type) return Hash_Type is |
| I, J, K : Integer'Base; |
| Index : Integer'Base; |
| |
| begin |
| I := Primes'Last - Primes'First; |
| Index := Primes'First; |
| while I > 0 loop |
| J := I / 2; |
| K := Index + J; |
| |
| if Primes (K) < Hash_Type (Length) then |
| Index := K + 1; |
| I := I - J - 1; |
| else |
| I := J; |
| end if; |
| end loop; |
| |
| return Primes (Index); |
| end To_Prime; |
| |
| end Ada.Containers.Prime_Numbers; |
