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) 1992-2008, 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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, 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. Note that in
  35 --  this package, wide character and wide wide character are not distinguished
  36 --  since this package is basically concerned with syntactic notions, and it
  37 --  deals with Char_Code values, rather than values of actual Ada types.
  38
  39 with Types; use Types;
  40
  41 package Widechar is
  42
  43    Wide_Char_Byte_Count : Nat := 0;
  44    --  This value is incremented whenever Scan_Wide or Skip_Wide is called.
  45    --  The amount added is the length of the wide character sequence minus
  46    --  one. This means that the count that accumulates here represents the
  47    --  difference between the length in characters and the length in bytes.
  48    --  This is used for checking the line length in characters.
  49
  50    function Length_Wide return Nat;
  51    --  Returns the maximum length in characters for the escape sequence that
  52    --  is used to encode wide character literals outside the ASCII range. Used
  53    --  only in the implementation of the attribute Width for Wide_Character
  54    --  and Wide_Wide_Character.
  55
  56    procedure Scan_Wide
  57      (S   : Source_Buffer_Ptr;
  58       P   : in out Source_Ptr;
  59       C   : out Char_Code;
  60       Err : out Boolean);
  61    --  On entry S (P) points to the first character in the source text for
  62    --  a wide character (i.e. to an ESC character, a left bracket, or an
  63    --  upper half character, depending on the representation method). A
  64    --  single wide character is scanned. If no error is found, the value
  65    --  stored in C is the code for this wide character, P is updated past
  66    --  the sequence and Err is set to False. If an error is found, then
  67    --  P points to the improper character, C is undefined, and Err is
  68    --  set to True.
  69
  70    procedure Set_Wide
  71      (C : Char_Code;
  72       S : in out String;
  73       P : in out Natural);
  74    --  The escape sequence (including any leading ESC character) for the
  75    --  given character code is stored starting at S (P + 1), and on return
  76    --  P points to the last stored character (i.e. P is the count of stored
  77    --  characters on entry and exit, and the escape sequence is appended to
  78    --  the end of the stored string). The character code C represents a code
  79    --  originally constructed by Scan_Wide, so it is known to be in a range
  80    --  that is appropriate for the encoding method in use.
  81
  82    procedure Skip_Wide (S : String; P : in out Natural);
  83    --  On entry, S (P) points to an ESC character for a wide character escape
  84    --  sequence or to an upper half character if the encoding method uses the
  85    --  upper bit, or to a left bracket if the brackets encoding method is in
  86    --  use. On exit, P is bumped past the wide character sequence. No error
  87    --  checking is done, since this is only used on escape sequences generated
  88    --  by Set_Wide, which are known to be correct.
  89
  90    procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr);
  91    --  Similar to the above procedure, but operates on a source buffer
  92    --  instead of a string, with P being a Source_Ptr referencing the
  93    --  contents of the source buffer.
  94
  95    function Is_Start_Of_Wide_Char
  96      (S : Source_Buffer_Ptr;
  97       P : Source_Ptr) return Boolean;
  98    --  Determines if S (P) is the start of a wide character sequence
  99
 100 end Widechar;