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