------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- G N A T . B Y T E _ O R D E R _ M A R K -- -- -- -- B o d y -- -- -- -- Copyright (C) 2006-2013, AdaCore -- -- -- -- 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 -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ pragma Compiler_Unit_Warning; package body GNAT.Byte_Order_Mark is -------------- -- Read_BOM -- -------------- procedure Read_BOM (Str : String; Len : out Natural; BOM : out BOM_Kind; XML_Support : Boolean := False) is begin -- Note: the order of these tests is important, because in some cases -- one sequence is a prefix of a longer sequence, and we must test for -- the longer sequence first -- UTF-32 (big-endian) if 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; -- UTF-32 (little-endian) 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_LE; -- UTF-16 (big-endian) elsif 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; -- UTF-16 (little-endian) 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; -- UTF-8 (endian-independent) 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; -- UCS-4 (big-endian) XML only elsif XML_Support and then 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#00#) and then Str (Str'First + 3) = Character'Val (16#3C#) then Len := 0; BOM := UCS4_BE; -- UCS-4 (little-endian) XML case elsif XML_Support and then Str'Length >= 4 and then Str (Str'First) = Character'Val (16#3C#) and then Str (Str'First + 1) = Character'Val (16#00#) and then Str (Str'First + 2) = Character'Val (16#00#) and then Str (Str'First + 3) = Character'Val (16#00#) then Len := 0; BOM := UCS4_LE; -- UCS-4 (unusual byte order 2143) XML case elsif XML_Support and then 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#3C#) and then Str (Str'First + 3) = Character'Val (16#00#) then Len := 0; BOM := UCS4_2143; -- UCS-4 (unusual byte order 3412) XML case elsif XML_Support and then Str'Length >= 4 and then Str (Str'First) = Character'Val (16#00#) and then Str (Str'First + 1) = Character'Val (16#3C#) and then Str (Str'First + 2) = Character'Val (16#00#) and then Str (Str'First + 3) = Character'Val (16#00#) then Len := 0; BOM := UCS4_3412; -- UTF-16 (big-endian) XML case elsif XML_Support and then Str'Length >= 4 and then Str (Str'First) = Character'Val (16#00#) and then Str (Str'First + 1) = Character'Val (16#3C#) and then Str (Str'First + 2) = Character'Val (16#00#) and then Str (Str'First + 3) = Character'Val (16#3F#) then Len := 0; BOM := UTF16_BE; -- UTF-32 (little-endian) XML case elsif XML_Support and then Str'Length >= 4 and then Str (Str'First) = Character'Val (16#3C#) and then Str (Str'First + 1) = Character'Val (16#00#) and then Str (Str'First + 2) = Character'Val (16#3F#) and then Str (Str'First + 3) = Character'Val (16#00#) then Len := 0; BOM := UTF16_LE; -- Unrecognized special encodings XML only elsif XML_Support and then Str'Length >= 4 and then Str (Str'First) = Character'Val (16#3C#) and then Str (Str'First + 1) = Character'Val (16#3F#) and then Str (Str'First + 2) = Character'Val (16#78#) and then Str (Str'First + 3) = Character'Val (16#6D#) then -- UTF-8, ASCII, some part of ISO8859, Shift-JIS, EUC,... Len := 0; BOM := Unknown; -- No BOM recognized else Len := 0; BOM := Unknown; end if; end Read_BOM; end GNAT.Byte_Order_Mark;