1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                             W I D E C H A R                              --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-1998 Free Software Foundation, Inc.          --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- As a special exception,  if other files  instantiate  generics from this --
23-- unit, or you link  this unit with other files  to produce an executable, --
24-- this  unit  does not  by itself cause  the resulting  executable  to  be --
25-- covered  by the  GNU  General  Public  License.  This exception does not --
26-- however invalidate  any other reasons why  the executable file  might be --
27-- covered by the  GNU Public License.                                      --
28--                                                                          --
29-- GNAT was originally developed  by the GNAT team at  New York University. --
30-- Extensive contributions were provided by Ada Core Technologies Inc.      --
31--                                                                          --
32------------------------------------------------------------------------------
33
34--  Subprograms for manipulation of wide character sequences
35
36with Types; use Types;
37
38package Widechar is
39
40   function Length_Wide return Nat;
41   --  Returns the maximum length in characters for the escape sequence that
42   --  is used to encode wide character literals outside the ASCII range. Used
43   --  only in the implementation of the attribute Width for Wide_Character.
44
45   procedure Scan_Wide
46     (S   : Source_Buffer_Ptr;
47      P   : in out Source_Ptr;
48      C   : out Char_Code;
49      Err : out Boolean);
50   --  On entry S (P) points to the first character in the source text for
51   --  a wide character (i.e. to an ESC character, a left bracket, or an
52   --  upper half character, depending on the representation method). A
53   --  single wide character is scanned. If no error is found, the value
54   --  stored in C is the code for this wide character, P is updated past
55   --  the sequence and Err is set to False. If an error is found, then
56   --  P points to the improper character, C is undefined, and Err is
57   --  set to True.
58
59   procedure Set_Wide
60     (C : Char_Code;
61      S : in out String;
62      P : in out Natural);
63   --  The escape sequence (including any leading ESC character) for the
64   --  given character code is stored starting at S (P + 1), and on return
65   --  P points to the last stored character (i.e. P is the count of stored
66   --  characters on entry and exit, and the escape sequence is appended to
67   --  the end of the stored string). The character code C represents a code
68   --  originally constructed by Scan_Wide, so it is known to be in a range
69   --  that is appropriate for the encoding method in use.
70
71   procedure Skip_Wide (S : String; P : in out Natural);
72   --  On entry, S (P) points to an ESC character for a wide character escape
73   --  sequence or to an upper half character if the encoding method uses the
74   --  upper bit, or to a left bracket if the brackets encoding method is in
75   --  use. On exit, P is bumped past the wide character sequence. No error
76   --  checking is done, since this is only used on escape sequences generated
77   --  by Set_Wide, which are known to be correct.
78
79   function Is_Start_Of_Wide_Char
80     (S    : Source_Buffer_Ptr;
81      P    : Source_Ptr)
82      return Boolean;
83   --  Determines if S (P) is the start of a wide character sequence
84
85end Widechar;
86