diff options
Diffstat (limited to 'gcc/ada/s-wchcon.ads')
| -rw-r--r-- | gcc/ada/s-wchcon.ads | 52 |
1 files changed, 30 insertions, 22 deletions
diff --git a/gcc/ada/s-wchcon.ads b/gcc/ada/s-wchcon.ads index 3c08176edf6..eecfe9f34ee 100644 --- a/gcc/ada/s-wchcon.ads +++ b/gcc/ada/s-wchcon.ads @@ -6,7 +6,7 @@ -- -- -- S p e c -- -- -- --- Copyright (C) 1992-2003 Free Software Foundation, Inc. -- +-- Copyright (C) 1992-2005 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- -- @@ -46,8 +46,8 @@ pragma Pure (WCh_Con); ------------------------------------- -- 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 @@ -62,9 +62,10 @@ pragma Pure (WCh_Con); -- 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 @@ -130,25 +131,32 @@ pragma Pure (WCh_Con); -- 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 + -- 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. 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. WC_Encoding_Letters : constant array (WC_Encoding_Method) of Character := (WCEM_Hex => 'h', @@ -170,8 +178,8 @@ pragma Pure (WCh_Con); -- 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 := 10; + -- 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. end System.WCh_Con; |