File : unicode-ces.adb
-----------------------------------------------------------------------
-- XML/Ada - An XML suite for Ada95 --
-- --
-- Copyright (C) 2001 --
-- ACT-Europe --
-- Author: Emmanuel Briot --
-- --
-- This library is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public --
-- License as published by the Free Software Foundation; either --
-- version 2 of the License, or (at your option) any later version. --
-- --
-- This library is distributed in the hope that it will be useful, --
-- but WITHOUT 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 along with this library; if not, write to the --
-- Free Software Foundation, Inc., 59 Temple Place - Suite 330, --
-- Boston, MA 02111-1307, 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. --
-----------------------------------------------------------------------
package body Unicode.CES is
--------------
-- Read_Bom --
--------------
procedure Read_Bom (Str : String; Len : out Natural; BOM : out Bom_Type) is
begin
if Str'Length >= 2
and then Str (Str'First) = Character'Val (16#FE#)
and then Str (Str'First + 1) = Character'Val (16#FF#)
then
Len := 2;
BOM := Utf16_BE;
elsif Str'Length >= 2
and then Str (Str'First) = Character'Val (16#FF#)
and then Str (Str'First + 1) = Character'Val (16#FE#)
then
Len := 2;
BOM := Utf16_LE;
elsif Str'Length >= 4
and then Str (Str'First) = Character'Val (16#00#)
and then Str (Str'First + 1) = Character'Val (16#00#)
and then Str (Str'First + 2) = Character'Val (16#FE#)
and then Str (Str'First + 3) = Character'Val (16#FF#)
then
Len := 4;
BOM := Utf32_BE;
elsif Str'Length >= 4
and then Str (Str'First) = Character'Val (16#FF#)
and then Str (Str'First + 1) = Character'Val (16#FE#)
and then Str (Str'First + 2) = Character'Val (16#00#)
and then Str (Str'First + 3) = Character'Val (16#00#)
then
Len := 4;
BOM := Utf32_BE;
elsif Str'Length >= 3
and then Str (Str'First) = Character'Val (16#EF#)
and then Str (Str'First + 1) = Character'Val (16#BB#)
and then Str (Str'First + 2) = Character'Val (16#BF#)
then
Len := 3;
BOM := Utf8_All;
else
Len := 0;
BOM := Unknown;
end if;
end Read_Bom;
-----------------------
-- Index_From_Offset --
-----------------------
function Index_From_Offset
(Str : Byte_Sequence; Offset : Natural; Encoding : Encoding_Scheme)
return Integer
is
Pos : Natural := Str'First;
Offs : Integer := Offset;
begin
while Pos <= Str'Last loop
if Offs <= 0 then
return Pos;
end if;
Pos := Pos + Encoding.Width (Encoding.Read (Str, Pos));
Offs := Offs - 1;
end loop;
return -1;
end Index_From_Offset;
end Unicode.CES;