54 lines
2.8 KiB
Ada
54 lines
2.8 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT LIBRARY COMPONENTS --
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-- --
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-- A D A . S T R I N G S . W I D E _ W I D E _ H A S H --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 2004-2006, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- This unit was originally developed by Matthew J Heaney. --
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------------------------------------------------------------------------------
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-- Note: source of this algorithm: GNAT.HTable.Hash (g-htable.adb)
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function Ada.Strings.Wide_Wide_Hash
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(Key : Wide_Wide_String) return Containers.Hash_Type
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is
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use Ada.Containers;
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function Rotate_Left
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(Value : Hash_Type;
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Amount : Natural) return Hash_Type;
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pragma Import (Intrinsic, Rotate_Left);
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Tmp : Hash_Type;
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begin
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Tmp := 0;
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for J in Key'Range loop
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Tmp := Rotate_Left (Tmp, 3) + Wide_Wide_Character'Pos (Key (J));
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end loop;
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return Tmp;
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end Ada.Strings.Wide_Wide_Hash;
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