| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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 -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- 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; |
