gcc/ada/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) 1992-2023, 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.  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 COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  Subprograms for manipulation of wide character sequences. Note that in
  27 --  this package, wide character and wide wide character are not distinguished
  28 --  since this package is basically concerned with syntactic notions, and it
  29 --  deals with Char_Code values, rather than values of actual Ada types.
  30
  31 with Types; use Types;
  32
  33 package Widechar is
  34
  35    Wide_Char_Byte_Count : Nat := 0;
  36    --  This value is incremented whenever Scan_Wide or Skip_Wide is called.
  37    --  The amount added is the length of the wide character sequence minus
  38    --  one. This means that the count that accumulates here represents the
  39    --  difference between the length in characters and the length in bytes.
  40    --  This is used for checking the line length in characters.
  41
  42    function Length_Wide return Nat;
  43    --  Returns the maximum length in characters for the escape sequence that
  44    --  is used to encode wide character literals outside the ASCII range. Used
  45    --  only in the implementation of the attribute Width for Wide_Character
  46    --  and Wide_Wide_Character.
  47
  48    procedure Scan_Wide
  49      (S   : Source_Buffer_Ptr;
  50       P   : in out Source_Ptr;
  51       C   : out Char_Code;
  52       Err : out Boolean);
  53    --  On entry S (P) points to the first character in the source text for
  54    --  a wide character (i.e. to an ESC character, a left bracket, or an
  55    --  upper half character, depending on the representation method). A
  56    --  single wide character is scanned. If no error is found, the value
  57    --  stored in C is the code for this wide character, P is updated past
  58    --  the sequence and Err is set to False. If an error is found, then
  59    --  P points to the improper character, C is undefined, and Err is
  60    --  set to True.
  61
  62    procedure Set_Wide
  63      (C : Char_Code;
  64       S : in out String;
  65       P : in out Natural);
  66    --  The escape sequence (including any leading ESC character) for the
  67    --  given character code is stored starting at S (P + 1), and on return
  68    --  P points to the last stored character (i.e. P is the count of stored
  69    --  characters on entry and exit, and the escape sequence is appended to
  70    --  the end of the stored string). The character code C represents a code
  71    --  originally constructed by Scan_Wide, so it is known to be in a range
  72    --  that is appropriate for the encoding method in use.
  73
  74    procedure Skip_Wide (S : String; P : in out Natural);
  75    --  On entry, S (P) points to an ESC character for a wide character escape
  76    --  sequence or to an upper half character if the encoding method uses the
  77    --  upper bit, or to a left bracket if the brackets encoding method is in
  78    --  use. On exit, P is bumped past the wide character sequence.
  79
  80    procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr);
  81    --  Similar to the above procedure, but operates on a source buffer
  82    --  instead of a string, with P being a Source_Ptr referencing the
  83    --  contents of the source buffer.
  84
  85    function Is_Start_Of_Wide_Char
  86      (S : Source_Buffer_Ptr;
  87       P : Source_Ptr) return Boolean;
  88    --  Determines if S (P) is the start of a wide character sequence
  89
  90 private
  91    pragma Inline (Is_Start_Of_Wide_Char);
  92
  93 end Widechar;