1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
------------------------------------------------------------------------------
-- --
-- GNAT LIBRARY COMPONENTS --
-- --
-- A D A . S T R I N G S . H A S H --
-- --
-- B o d y --
-- --
-- Copyright (C) 2004-2006, 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 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. --
------------------------------------------------------------------------------
-- Note: source of this algorithm: GNAT.HTable.Hash (g-htable.adb)
function Ada.Strings.Hash (Key : String) return Containers.Hash_Type is
use Ada.Containers;
function Rotate_Left
(Value : Hash_Type;
Amount : Natural) return Hash_Type;
pragma Import (Intrinsic, Rotate_Left);
Tmp : Hash_Type;
begin
Tmp := 0;
for J in Key'Range loop
Tmp := Rotate_Left (Tmp, 3) + Character'Pos (Key (J));
end loop;
return Tmp;
end Ada.Strings.Hash;
|
