File : 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) 1992-2014, 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 -- --
19 -- --
20 -- --
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;