gcc/ada/s-valuti.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                      S Y S T E M . V A L _ U T I L                       --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2006, 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 --  This package provides some common utilities used by the s-valxxx files
  35
  36 package System.Val_Util is
  37    pragma Pure;
  38
  39    procedure Normalize_String
  40      (S    : in out String;
  41       F, L : out Integer);
  42    --  This procedure scans the string S setting F to be the index of the first
  43    --  non-blank character of S and L to be the index of the last non-blank
  44    --  character of S. Any lower case characters present in S will be folded
  45    --  to their upper case equivalent except for character literals. If S
  46    --  consists of entirely blanks then Constraint_Error is raised.
  47    --
  48    --  Note: if S is the null string, F is set to S'First, L to S'Last
  49
  50    procedure Scan_Sign
  51      (Str   : String;
  52       Ptr   : access Integer;
  53       Max   : Integer;
  54       Minus : out Boolean;
  55       Start : out Positive);
  56    --  The Str, Ptr, Max parameters are as for the scan routines (Str is the
  57    --  string to be scanned starting at Ptr.all, and Max is the index of the
  58    --  last character in the string). Scan_Sign first scans out any initial
  59    --  blanks, raising Constraint_Error if the field is all blank. It then
  60    --  checks for and skips an initial plus or minus, requiring a non-blank
  61    --  character to follow (Constraint_Error is raised if plus or minus
  62    --  appears at the end of the string or with a following blank). Minus is
  63    --  set True if a minus sign was skipped, and False otherwise. On exit
  64    --  Ptr.all points to the character after the sign, or to the first
  65    --  non-blank character if no sign is present. Start is set to the point
  66    --  to the first non-blank character (sign or digit after it).
  67    --
  68    --  Note: if Str is null, i.e. if Max is less than Ptr, then this is a
  69    --  special case of an all-blank string, and Ptr is unchanged, and hence
  70    --  is greater than Max as required in this case. Constraint_Error is
  71    --  also raised in this case.
  72
  73    procedure Scan_Plus_Sign
  74      (Str   : String;
  75       Ptr   : access Integer;
  76       Max   : Integer;
  77       Start : out Positive);
  78    --  Same as Scan_Sign, but allows only plus, not minus.
  79    --  This is used for modular types.
  80
  81    function Scan_Exponent
  82      (Str  : String;
  83       Ptr  : access Integer;
  84       Max  : Integer;
  85       Real : Boolean := False) return Integer;
  86    --  Called to scan a possible exponent. Str, Ptr, Max are as described above
  87    --  for Scan_Sign. If Ptr.all < Max and Str (Ptr.all) = 'E' or 'e', then an
  88    --  exponent is scanned out, with the exponent value returned in Exp, and
  89    --  Ptr.all updated to point past the exponent. If the exponent field is
  90    --  incorrectly formed or not present, then Ptr.all is unchanged, and the
  91    --  returned exponent value is zero. Real indicates whether a minus sign
  92    --  is permitted (True = permitted). Very large exponents are handled by
  93    --  returning a suitable large value. If the base is zero, then any value
  94    --  is allowed, and otherwise the large value will either cause underflow
  95    --  or overflow during the scaling process which is fine.
  96
  97    procedure Scan_Trailing_Blanks (Str : String; P : Positive);
  98    --  Checks that the remainder of the field Str (P .. Str'Last) is all
  99    --  blanks. Raises Constraint_Error if a non-blank character is found.
 100
 101    procedure Scan_Underscore
 102      (Str : String;
 103       P   : in out Natural;
 104       Ptr : access Integer;
 105       Max : Integer;
 106       Ext : Boolean);
 107    --  Called if an underscore is encountered while scanning digits. Str (P)
 108    --  contains the underscore. Ptr it the pointer to be returned to the
 109    --  ultimate caller of the scan routine, Max is the maximum subscript in
 110    --  Str, and Ext indicates if extended digits are allowed. In the case
 111    --  where the underscore is invalid, Constraint_Error is raised with Ptr
 112    --  set appropriately, otherwise control returns with P incremented past
 113    --  the underscore.
 114
 115 end System.Val_Util;