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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- W I D E C H A R --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2008, 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- --
-- 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, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, 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. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- Subprograms for manipulation of wide character sequences. Note that in
-- this package, wide character and wide wide character are not distinguished
-- since this package is basically concerned with syntactic notions, and it
-- deals with Char_Code values, rather than values of actual Ada types.
with Types; use Types;
package Widechar is
Wide_Char_Byte_Count : Nat := 0;
-- This value is incremented whenever Scan_Wide or Skip_Wide is called.
-- The amount added is the length of the wide character sequence minus
-- one. This means that the count that accumulates here represents the
-- difference between the length in characters and the length in bytes.
-- This is used for checking the line length in characters.
function Length_Wide return Nat;
-- Returns the maximum length in characters for the escape sequence that
-- is used to encode wide character literals outside the ASCII range. Used
-- only in the implementation of the attribute Width for Wide_Character
-- and Wide_Wide_Character.
procedure Scan_Wide
(S : Source_Buffer_Ptr;
P : in out Source_Ptr;
C : out Char_Code;
Err : out Boolean);
-- On entry S (P) points to the first character in the source text for
-- a wide character (i.e. to an ESC character, a left bracket, or an
-- upper half character, depending on the representation method). A
-- single wide character is scanned. If no error is found, the value
-- stored in C is the code for this wide character, P is updated past
-- the sequence and Err is set to False. If an error is found, then
-- P points to the improper character, C is undefined, and Err is
-- set to True.
procedure Set_Wide
(C : Char_Code;
S : in out String;
P : in out Natural);
-- The escape sequence (including any leading ESC character) for the
-- given character code is stored starting at S (P + 1), and on return
-- P points to the last stored character (i.e. P is the count of stored
-- characters on entry and exit, and the escape sequence is appended to
-- the end of the stored string). The character code C represents a code
-- originally constructed by Scan_Wide, so it is known to be in a range
-- that is appropriate for the encoding method in use.
procedure Skip_Wide (S : String; P : in out Natural);
-- On entry, S (P) points to an ESC character for a wide character escape
-- sequence or to an upper half character if the encoding method uses the
-- upper bit, or to a left bracket if the brackets encoding method is in
-- use. On exit, P is bumped past the wide character sequence. No error
-- checking is done, since this is only used on escape sequences generated
-- by Set_Wide, which are known to be correct.
procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr);
-- Similar to the above procedure, but operates on a source buffer
-- instead of a string, with P being a Source_Ptr referencing the
-- contents of the source buffer.
function Is_Start_Of_Wide_Char
(S : Source_Buffer_Ptr;
P : Source_Ptr) return Boolean;
-- Determines if S (P) is the start of a wide character sequence
end Widechar;
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