char_io.spc

--------------------------------------------------------------------------
-- ASnip Source Code Decorator
-- Copyright (C) 2006, Georg Bauhaus
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--    modified version of this package.
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--------------------------------------------------------------------------
--                                                eMail: bauhaus@arcor.de

with Ada.Streams;
with ASnip;  use ASnip;

package Char_IO is
      
   subtype ROOT_STREAM_TYPE is Ada.Streams.ROOT_STREAM_TYPE;

      malformed_encoding: exception;

      -- functions actually performing I/O. BMP only.

      type CHAR_READER is abstract tagged null record;
      --access function(source: access ROOT_STREAM_TYPE'class) return CHAR;
      function read_next_char
         (the_reader: CHAR_READER;
         source: access ROOT_STREAM_TYPE'class) return CHAR is abstract;

      type READS_UTF_8 is new CHAR_READER with null record;
      function read_next_char
         (the_reader: READS_UTF_8;
         source: access ROOT_STREAM_TYPE'class) return CHAR;

      type READS_UTF_16 is new CHAR_READER with null record;
      function read_next_char
         (the_reader: READS_UTF_16;
         source: access ROOT_STREAM_TYPE'class) return CHAR;

      type READS_UTF_16LE is new CHAR_READER with null record;
      function read_next_char
         (the_reader: READS_UTF_16LE;
         source: access ROOT_STREAM_TYPE'class) return CHAR;
         -- byte order issue?

      type READS_8859 is new CHAR_READER with null record;
      function read_next_char
         (the_reader: READS_8859;
         source: access ROOT_STREAM_TYPE'class) return CHAR;

   R8859: aliased constant Char_IO.READS_8859 := (null record);
   RUTF8: aliased constant Char_IO.READS_UTF_8 := (null record);
   RUTF16: aliased constant Char_IO.READS_UTF_16 := (null record);
   RUTF16LE: aliased constant Char_IO.READS_UTF_16LE := (null record);

end Char_IO;