| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . S T R I N G _ H A S H -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2009, 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 3, 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. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package provides a generic hashing function over strings, suitable for |
| -- use with a string keyed hash table. In particular, it is the basis for the |
| -- string hash functions in Ada.Containers. |
| -- |
| -- The algorithm used here is not appropriate for applications that require |
| -- cryptographically strong hashes, or for application which wish to use very |
| -- wide hash values as pseudo unique identifiers. In such cases please refer |
| -- to GNAT.SHA1 and GNAT.MD5. |
| |
| package System.String_Hash is |
| pragma Pure; |
| |
| generic |
| type Char_Type is (<>); |
| -- The character type composing the key string type |
| |
| type Key_Type is array (Positive range <>) of Char_Type; |
| -- The string type to use as a hash key |
| |
| type Hash_Type is mod <>; |
| -- The type to be returned as a hash value. This must be a 32-bit |
| -- unsigned type with full range 0 .. 2**32-1, no other type is allowed |
| -- for this instantiation (checked in the body by Compile_Time_Error). |
| |
| function Hash (Key : Key_Type) return Hash_Type; |
| pragma Inline (Hash); |
| -- Compute a hash value for a key |
| |
| end System.String_Hash; |
