File : widechar.ads
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) 1992-2014, 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 3, 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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- Subprograms for manipulation of wide character sequences. Note that in
33 -- this package, wide character and wide wide character are not distinguished
34 -- since this package is basically concerned with syntactic notions, and it
35 -- deals with Char_Code values, rather than values of actual Ada types.
36
37 with Types; use Types;
38
39 package Widechar is
40
41 Wide_Char_Byte_Count : Nat := 0;
42 -- This value is incremented whenever Scan_Wide or Skip_Wide is called.
43 -- The amount added is the length of the wide character sequence minus
44 -- one. This means that the count that accumulates here represents the
45 -- difference between the length in characters and the length in bytes.
46 -- This is used for checking the line length in characters.
47
48 function Length_Wide return Nat;
49 -- Returns the maximum length in characters for the escape sequence that
50 -- is used to encode wide character literals outside the ASCII range. Used
51 -- only in the implementation of the attribute Width for Wide_Character
52 -- and Wide_Wide_Character.
53
54 procedure Scan_Wide
55 (S : Source_Buffer_Ptr;
56 P : in out Source_Ptr;
57 C : out Char_Code;
58 Err : out Boolean);
59 -- On entry S (P) points to the first character in the source text for
60 -- a wide character (i.e. to an ESC character, a left bracket, or an
61 -- upper half character, depending on the representation method). A
62 -- single wide character is scanned. If no error is found, the value
63 -- stored in C is the code for this wide character, P is updated past
64 -- the sequence and Err is set to False. If an error is found, then
65 -- P points to the improper character, C is undefined, and Err is
66 -- set to True.
67
68 procedure Set_Wide
69 (C : Char_Code;
70 S : in out String;
71 P : in out Natural);
72 -- The escape sequence (including any leading ESC character) for the
73 -- given character code is stored starting at S (P + 1), and on return
74 -- P points to the last stored character (i.e. P is the count of stored
75 -- characters on entry and exit, and the escape sequence is appended to
76 -- the end of the stored string). The character code C represents a code
77 -- originally constructed by Scan_Wide, so it is known to be in a range
78 -- that is appropriate for the encoding method in use.
79
80 procedure Skip_Wide (S : String; P : in out Natural);
81 -- On entry, S (P) points to an ESC character for a wide character escape
82 -- sequence or to an upper half character if the encoding method uses the
83 -- upper bit, or to a left bracket if the brackets encoding method is in
84 -- use. On exit, P is bumped past the wide character sequence. No error
85 -- checking is done, since this is only used on escape sequences generated
86 -- by Set_Wide, which are known to be correct.
87
88 procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr);
89 -- Similar to the above procedure, but operates on a source buffer
90 -- instead of a string, with P being a Source_Ptr referencing the
91 -- contents of the source buffer.
92
93 function Is_Start_Of_Wide_Char
94 (S : Source_Buffer_Ptr;
95 P : Source_Ptr) return Boolean;
96 -- Determines if S (P) is the start of a wide character sequence
97
98 end Widechar;