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) 1992-2009, 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 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  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 --  This package provides some common utilities used by the s-valxxx files
  33
  34 package System.Val_Util is
  35    pragma Pure;
  36
  37    procedure Normalize_String
  38      (S    : in out String;
  39       F, L : out Integer);
  40    --  This procedure scans the string S setting F to be the index of the first
  41    --  non-blank character of S and L to be the index of the last non-blank
  42    --  character of S. Any lower case characters present in S will be folded
  43    --  to their upper case equivalent except for character literals. If S
  44    --  consists of entirely blanks then Constraint_Error is raised.
  45    --
  46    --  Note: if S is the null string, F is set to S'First, L to S'Last
  47
  48    procedure Scan_Sign
  49      (Str   : String;
  50       Ptr   : not null access Integer;
  51       Max   : Integer;
  52       Minus : out Boolean;
  53       Start : out Positive);
  54    --  The Str, Ptr, Max parameters are as for the scan routines (Str is the
  55    --  string to be scanned starting at Ptr.all, and Max is the index of the
  56    --  last character in the string). Scan_Sign first scans out any initial
  57    --  blanks, raising Constraint_Error if the field is all blank. It then
  58    --  checks for and skips an initial plus or minus, requiring a non-blank
  59    --  character to follow (Constraint_Error is raised if plus or minus
  60    --  appears at the end of the string or with a following blank). Minus is
  61    --  set True if a minus sign was skipped, and False otherwise. On exit
  62    --  Ptr.all points to the character after the sign, or to the first
  63    --  non-blank character if no sign is present. Start is set to the point
  64    --  to the first non-blank character (sign or digit after it).
  65    --
  66    --  Note: if Str is null, i.e. if Max is less than Ptr, then this is a
  67    --  special case of an all-blank string, and Ptr is unchanged, and hence
  68    --  is greater than Max as required in this case. Constraint_Error is
  69    --  also raised in this case.
  70
  71    procedure Scan_Plus_Sign
  72      (Str   : String;
  73       Ptr   : not null access Integer;
  74       Max   : Integer;
  75       Start : out Positive);
  76    --  Same as Scan_Sign, but allows only plus, not minus.
  77    --  This is used for modular types.
  78
  79    function Scan_Exponent
  80      (Str  : String;
  81       Ptr  : not null access Integer;
  82       Max  : Integer;
  83       Real : Boolean := False) return Integer;
  84    --  Called to scan a possible exponent. Str, Ptr, Max are as described above
  85    --  for Scan_Sign. If Ptr.all < Max and Str (Ptr.all) = 'E' or 'e', then an
  86    --  exponent is scanned out, with the exponent value returned in Exp, and
  87    --  Ptr.all updated to point past the exponent. If the exponent field is
  88    --  incorrectly formed or not present, then Ptr.all is unchanged, and the
  89    --  returned exponent value is zero. Real indicates whether a minus sign
  90    --  is permitted (True = permitted). Very large exponents are handled by
  91    --  returning a suitable large value. If the base is zero, then any value
  92    --  is allowed, and otherwise the large value will either cause underflow
  93    --  or overflow during the scaling process which is fine.
  94
  95    procedure Scan_Trailing_Blanks (Str : String; P : Positive);
  96    --  Checks that the remainder of the field Str (P .. Str'Last) is all
  97    --  blanks. Raises Constraint_Error if a non-blank character is found.
  98
  99    procedure Scan_Underscore
 100      (Str : String;
 101       P   : in out Natural;
 102       Ptr : not null access Integer;
 103       Max : Integer;
 104       Ext : Boolean);
 105    --  Called if an underscore is encountered while scanning digits. Str (P)
 106    --  contains the underscore. Ptr it the pointer to be returned to the
 107    --  ultimate caller of the scan routine, Max is the maximum subscript in
 108    --  Str, and Ext indicates if extended digits are allowed. In the case
 109    --  where the underscore is invalid, Constraint_Error is raised with Ptr
 110    --  set appropriately, otherwise control returns with P incremented past
 111    --  the underscore.
 112
 113 end System.Val_Util;