-- --
-- S p e c --
-- --
--- $Revision: 1.10 $ --
--- --
--- Copyright (C) 1992-1998 Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
-- --
-- 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 2, or (at your option) any later ver- --
+-- 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. See the GNU General Public License --
--- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- 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. --
-- --
--- 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. --
+-- 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. --
--- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- wide characters in string and character constants. This is needed both
-- at compile time and at runtime (for the wide character runtime routines)
+-- This unit may be used directly from an application program by providing
+-- an appropriate WITH, and the interface can be expected to remain stable.
+
+pragma Compiler_Unit;
+
package System.WCh_Con is
-pragma Pure (WCh_Con);
+ pragma Pure;
-------------------------------------
-- Wide_Character Encoding Methods --
-------------------------------------
-- A wide character encoding method is a method for uniquely representing
- -- a Wide_Character value using a one or more Character values. Three
- -- types of encoding method are supported by GNAT:
+ -- a Wide_Character or Wide_Wide_Character value using a one or more
+ -- Character values. Three types of encoding method are supported by GNAT:
-- An escape encoding method uses ESC as the first character of the
-- sequence, and subsequent characters determine the wide character
-- Any character in the lower half (16#00# .. 16#7F#) represents
-- itself as a single character.
- -- The brackets notation, where a wide character is represented
- -- by the sequence ["xx"] or ["xxxx"] where xx are hexadecimal
- -- characters.
+ -- The brackets notation, where a wide character is represented by the
+ -- sequence ["xx"] or ["xxxx"] or ["xxxxxx"] where xx are hexadecimal
+ -- characters. Note that currently this is the only encoding that
+ -- supports the full UTF-32 range.
-- Note that GNAT does not currently support escape-in, escape-out
-- encoding methods, where an escape sequence is used to set a mode
-- 4. Adjust definition of WC_Longest_Sequence if necessary
-- 5. Add an entry in WC_Encoding_Letters for the new method
-- 6. Add proper code to s-wchstw.adb, s-wchwts.adb, s-widwch.adb
+ -- 7. Update documentation (remember section on form strings)
-- Note that the WC_Encoding_Method values must be kept ordered so that
-- the definitions of the subtypes WC_Upper_Half_Encoding_Method and
-- sequence ESC a b c d (five characters, where abcd are ASCII hex
-- characters, using upper case for letters). This method is easy
-- to deal with in external environments that do not support wide
- -- characters, and covers the whole BMP. This is the default encoding
- -- method.
+ -- characters, and covers the whole 16-bit BMP. Codes larger than
+ -- 16#FFFF# are not representable using this encoding method.
WCEM_Upper : constant WC_Encoding_Method := 2;
-- The wide character with encoding 16#abcd#, where the upper bit is on
-- 16#cd#. The second byte may never be a format control character, but
-- is not required to be in the upper half. This method can be also used
-- for shift-JIS or EUC where the internal coding matches the external
- -- coding.
+ -- coding. Codes larger than 16#FFFF# are not representable using this
+ -- encoding method.
WCEM_Shift_JIS : constant WC_Encoding_Method := 3;
-- A wide character is represented by a two character sequence 16#ab#
-- as described above. The internal character code is the corresponding
-- JIS character according to the standard algorithm for Shift-JIS
-- conversion. See the body of package System.JIS_Conversions for
- -- further details.
+ -- further details. Codes larger than 16#FFFF are not representable
+ -- using this encoding method.
WCEM_EUC : constant WC_Encoding_Method := 4;
-- A wide character is represented by a two character sequence 16#ab# and
-- 16#cd#, with both characters being in the upper half set. The internal
-- character code is the corresponding JIS character according to the EUC
-- encoding algorithm. See the body of package System.JIS_Conversions for
- -- further details.
+ -- further details. Codes larger than 16#FFFF# are not representable using
+ -- this encoding method.
WCEM_UTF8 : constant WC_Encoding_Method := 5;
- -- An ISO 10646-1 BMP/Unicode wide character is represented in
- -- UCS Transformation Format 8 (UTF-8) as defined in Annex R of ISO
- -- 10646-1/Am.2. Depending on the character value, a Unicode character
- -- is represented as the one, two, or three byte sequence
+ -- An ISO 10646-1 BMP/Unicode wide character is represented in UCS
+ -- Transformation Format 8 (UTF-8), as defined in Annex R of ISO
+ -- 10646-1/Am.2. Depending on the character value, a Unicode character
+ -- is represented as the one to six byte sequence.
--
- -- 16#0000#-16#007f#: 2#0xxxxxxx#
- -- 16#0080#-16#07ff#: 2#110xxxxx# 2#10xxxxxx#
- -- 16#0800#-16#ffff#: 2#1110xxxx# 2#10xxxxxx# 2#10xxxxxx#
+ -- 16#0000_0000#-16#0000_007f#: 2#0xxxxxxx#
+ -- 16#0000_0080#-16#0000_07ff#: 2#110xxxxx# 2#10xxxxxx#
+ -- 16#0000_0800#-16#0000_ffff#: 2#1110xxxx# 2#10xxxxxx# 2#10xxxxxx#
+ -- 16#0001_0000#-16#001F_FFFF#: 2#11110xxx# 2#10xxxxxx# 2#10xxxxxx#
+ -- 2#10xxxxxx#
+ -- 16#0020_0000#-16#03FF_FFFF#: 2#111110xx# 2#10xxxxxx# 2#10xxxxxx#
+ -- 2#10xxxxxx# 2#10xxxxxx#
+ -- 16#0400_0000#-16#7FFF_FFFF#: 2#1111110x# 2#10xxxxxx# 2#10xxxxxx#
+ -- 2#10xxxxxx# 2#10xxxxxx# 2#10xxxxxx#
--
- -- where the xxx bits correspond to the left-padded bits of the the
+ -- where the xxx bits correspond to the left-padded bits of the
-- 16-bit character value. Note that all lower half ASCII characters
-- are represented as ASCII bytes and all upper half characters and
- -- other wide characters are represented as sequences of upper-half
- -- (The full UTF-8 scheme allows for encoding 31-bit characters as
- -- 6-byte sequences, but in this implementation, all UTF-8 sequences
- -- of four or more bytes length will raise a Constraint_Error, as
- -- will all illegal UTF-8 sequences.)
+ -- other wide characters are represented as sequences of upper-half. This
+ -- encoding method can represent the entire range of Wide_Wide_Character.
WCEM_Brackets : constant WC_Encoding_Method := 6;
- -- A wide character is represented as the sequence ["abcd"] where abcd
- -- are four hexadecimal characters. In this mode, the sequence ["ab"]
- -- is also recognized for the case of character codes in the range 0-255.
+ -- A wide character is represented using one of the following sequences:
+ --
+ -- ["xx"]
+ -- ["xxxx"]
+ -- ["xxxxxx"]
+ -- ["xxxxxxxx"]
+ --
+ -- where xx are hexadecimal digits representing the character code. This
+ -- encoding method can represent the entire range of Wide_Wide_Character
+ -- but in the general case results in ambiguous representations (there is
+ -- no ambiguity in Ada sources, since the above sequences are illegal Ada).
WC_Encoding_Letters : constant array (WC_Encoding_Method) of Character :=
(WCEM_Hex => 'h',
subtype WC_ESC_Encoding_Method is
WC_Encoding_Method range WCEM_Hex .. WCEM_Hex;
- -- Encoding methods using an ESC character at the start of the sequence.
+ -- Encoding methods using an ESC character at the start of the sequence
subtype WC_Upper_Half_Encoding_Method is
WC_Encoding_Method range WCEM_Upper .. WCEM_UTF8;
-- Encoding methods using an upper half character (16#80#..16#FF) at
-- the start of the sequence.
- WC_Longest_Sequence : constant := 8;
- -- The longest number of characters that can be used for a wide
- -- character sequence for any of the active encoding methods.
+ WC_Longest_Sequence : constant := 12;
+ -- The longest number of characters that can be used for a wide character
+ -- or wide wide character sequence for any of the active encoding methods.
+
+ WC_Longest_Sequences : constant array (WC_Encoding_Method) of Natural :=
+ (WCEM_Hex => 5,
+ WCEM_Upper => 2,
+ WCEM_Shift_JIS => 2,
+ WCEM_EUC => 2,
+ WCEM_UTF8 => 6,
+ WCEM_Brackets => 12);
+ -- The longest number of characters that can be used for a wide character
+ -- or wide wide character sequence using the given encoding method.
+
+ function Get_WC_Encoding_Method (C : Character) return WC_Encoding_Method;
+ -- Given a character C, returns corresponding encoding method (see array
+ -- WC_Encoding_Letters above). Raises Constraint_Error if not in list.
+
+ function Get_WC_Encoding_Method (S : String) return WC_Encoding_Method;
+ -- Given a lower case string that is one of hex, upper, shift_jis, euc,
+ -- utf8, brackets, return the corresponding encoding method. Raises
+ -- Constraint_Error if not in list.
+
+ function Is_Start_Of_Encoding
+ (C : Character;
+ EM : WC_Encoding_Method) return Boolean;
+ pragma Inline (Is_Start_Of_Encoding);
+ -- Returns True if the Character C is the start of a multi-character
+ -- encoding sequence for the given encoding method EM. If EM is set to
+ -- WCEM_Brackets, this function always returns False.
end System.WCh_Con;
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