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) 1992-2012, 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
34package 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
47   --  to their upper case equivalent except for character literals. If S
48   --  consists 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
64   --  appears at the end of the string or with a following blank). Minus is
65   --  set True if a minus sign was skipped, and False otherwise. On exit
66   --  Ptr.all points to the character after the sign, or to the first
67   --  non-blank character if no sign is present. Start is set to the point
68   --  to the first non-blank 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
73   --  also raised in this case.
74
75   procedure Scan_Plus_Sign
76     (Str   : String;
77      Ptr   : not null access Integer;
78      Max   : Integer;
79      Start : out Positive);
80   --  Same as Scan_Sign, but allows only plus, not minus.
81   --  This is used for modular types.
82
83   function Scan_Exponent
84     (Str  : String;
85      Ptr  : not null access Integer;
86      Max  : Integer;
87      Real : Boolean := False) return Integer;
88   --  Called to scan a possible exponent. Str, Ptr, Max are as described above
89   --  for Scan_Sign. If Ptr.all < Max and Str (Ptr.all) = 'E' or 'e', then an
90   --  exponent is scanned out, with the exponent value returned in Exp, and
91   --  Ptr.all updated to point past the exponent. If the exponent field is
92   --  incorrectly formed or not present, then Ptr.all is unchanged, and the
93   --  returned exponent value is zero. Real indicates whether a minus sign
94   --  is permitted (True = permitted). Very large exponents are handled by
95   --  returning a suitable large value. If the base is zero, then any value
96   --  is allowed, and otherwise the large value will either cause underflow
97   --  or overflow during the scaling process which is fine.
98
99   procedure Scan_Trailing_Blanks (Str : String; P : Positive);
100   --  Checks that the remainder of the field Str (P .. Str'Last) is all
101   --  blanks. Raises Constraint_Error if a non-blank character is found.
102
103   procedure Scan_Underscore
104     (Str : String;
105      P   : in out Natural;
106      Ptr : not null access Integer;
107      Max : Integer;
108      Ext : Boolean);
109   --  Called if an underscore is encountered while scanning digits. Str (P)
110   --  contains the underscore. Ptr it the pointer to be returned to the
111   --  ultimate caller of the scan routine, Max is the maximum subscript in
112   --  Str, and Ext indicates if extended digits are allowed. In the case
113   --  where the underscore is invalid, Constraint_Error is raised with Ptr
114   --  set appropriately, otherwise control returns with P incremented past
115   --  the underscore.
116
117end System.Val_Util;
118