gcc/ada/libgnat/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) 1992-2017, 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 Bad_Value (S : String);
  38    pragma No_Return (Bad_Value);
  39    --  Raises constraint error with message: bad input for 'Value: "xxx"
  40
  41    procedure Normalize_String
  42      (S    : in out String;
  43       F, L : out Integer);
  44    --  This procedure scans the string S setting F to be the index of the first
  45    --  non-blank character of S and L to be the index of the last non-blank
  46    --  character of S. Any lower case characters present in S will be folded to
  47    --  their upper case equivalent except for character literals. If S consists
  48    --  of entirely blanks then Constraint_Error is raised.
  49    --
  50    --  Note: if S is the null string, F is set to S'First, L to S'Last
  51
  52    procedure Scan_Sign
  53      (Str   : String;
  54       Ptr   : not null access Integer;
  55       Max   : Integer;
  56       Minus : out Boolean;
  57       Start : out Positive);
  58    --  The Str, Ptr, Max parameters are as for the scan routines (Str is the
  59    --  string to be scanned starting at Ptr.all, and Max is the index of the
  60    --  last character in the string). Scan_Sign first scans out any initial
  61    --  blanks, raising Constraint_Error if the field is all blank. It then
  62    --  checks for and skips an initial plus or minus, requiring a non-blank
  63    --  character to follow (Constraint_Error is raised if plus or minus appears
  64    --  at the end of the string or with a following blank). Minus is set True
  65    --  if a minus sign was skipped, and False otherwise. On exit Ptr.all points
  66    --  to the character after the sign, or to the first non-blank character
  67    --  if no sign is present. Start is set to the point to the first non-blank
  68    --  character (sign or digit after it).
  69    --
  70    --  Note: if Str is null, i.e. if Max is less than Ptr, then this is a
  71    --  special case of an all-blank string, and Ptr is unchanged, and hence
  72    --  is greater than Max as required in this case. Constraint_Error is also
  73    --  raised in this case.
  74    --
  75    --  This routine must not be called with Str'Last = Positive'Last. There is
  76    --  no check for this case, the caller must ensure this condition is met.
  77
  78    procedure Scan_Plus_Sign
  79      (Str   : String;
  80       Ptr   : not null access Integer;
  81       Max   : Integer;
  82       Start : out Positive);
  83    --  Same as Scan_Sign, but allows only plus, not minus. This is used for
  84    --  modular types.
  85
  86    function Scan_Exponent
  87      (Str  : String;
  88       Ptr  : not null access Integer;
  89       Max  : Integer;
  90       Real : Boolean := False) return Integer;
  91    --  Called to scan a possible exponent. Str, Ptr, Max are as described above
  92    --  for Scan_Sign. If Ptr.all < Max and Str (Ptr.all) = 'E' or 'e', then an
  93    --  exponent is scanned out, with the exponent value returned in Exp, and
  94    --  Ptr.all updated to point past the exponent. If the exponent field is
  95    --  incorrectly formed or not present, then Ptr.all is unchanged, and the
  96    --  returned exponent value is zero. Real indicates whether a minus sign
  97    --  is permitted (True = permitted). Very large exponents are handled by
  98    --  returning a suitable large value. If the base is zero, then any value
  99    --  is allowed, and otherwise the large value will either cause underflow
 100    --  or overflow during the scaling process which is fine.
 101    --
 102    --  This routine must not be called with Str'Last = Positive'Last. There is
 103    --  no check for this case, the caller must ensure this condition is met.
 104
 105    procedure Scan_Trailing_Blanks (Str : String; P : Positive);
 106    --  Checks that the remainder of the field Str (P .. Str'Last) is all
 107    --  blanks. Raises Constraint_Error if a non-blank character is found.
 108
 109    procedure Scan_Underscore
 110      (Str : String;
 111       P   : in out Natural;
 112       Ptr : not null access Integer;
 113       Max : Integer;
 114       Ext : Boolean);
 115    --  Called if an underscore is encountered while scanning digits. Str (P)
 116    --  contains the underscore. Ptr it the pointer to be returned to the
 117    --  ultimate caller of the scan routine, Max is the maximum subscript in
 118    --  Str, and Ext indicates if extended digits are allowed. In the case
 119    --  where the underscore is invalid, Constraint_Error is raised with Ptr
 120    --  set appropriately, otherwise control returns with P incremented past
 121    --  the underscore.
 122    --
 123    --  This routine must not be called with Str'Last = Positive'Last. There is
 124    --  no check for this case, the caller must ensure this condition is met.
 125
 126 end System.Val_Util;