File : unicode-ccs.ads


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--                XML/Ada - An XML suite for Ada95                   --

--                                                                   --

--                       Copyright (C) 2001                          --

--                            ACT-Europe                             --

--                       Author: Emmanuel Briot                      --

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-- This library is free software; you can redistribute it and/or     --

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--  This is the root of the hierarchy that provides coded character sets.

--  These CCS can be used to convert from any encoding (like Iso/Latin-1)

--  to Unicode.

--  See http://www.isoc.org:8080/codage/iso8859/jeuxiso.en.htm for a list

--  of the ISO 8859-*  character sets


package Unicode.CCS is

   --  Each of the child package shall have two public functions with

   --  the following profile:

   --    function Convert (Char : Unicode_Char) return Unicode_Char

   --  that converts from a code point representing an abstract character in

   --  the specific encoding to the code point for the same character in

   --  Unicode, or reverse


   type Conversion_Function is access
     function (Char : Unicode_Char) return Unicode_Char;

   type Character_Set is record
      To_Unicode : Conversion_Function;
      To_CS      : Conversion_Function;
   end record;

   --------------------

   -- Character sets --

   --------------------


   function Get_Character_Set (Name : String) return Character_Set;
   --  Get the character set associated with a given name

   --  The valid names are given in the packages Unicode.CCS.*.

   --  Unknown_Character_Set is raised if Name is not found.


   function Identity (Char : Unicode_Char) return Unicode_Char;
   --  return its parameter directly.


   Unicode_Character_Set : constant Character_Set :=
     (To_Unicode => Identity'Access,
      To_Cs      => Identity'Access);

   Invalid_Code : exception;
   --  Exception raised when trying to convert to a code point that

   --  is not available in the specific character set. This can never be

   --  raised when converting to Unicode, since it is universal by definition.


   Unknown_Character_Set : exception;
   --  Raised by Get_Conversion or Get_Revert_Conversion when the name is

   --  unknown.


end Unicode.CCS;