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1------------------------------------------------------------------------------
2-- --
3-- GNAT COMPILER COMPONENTS --
4-- --
5-- S Y S T E M . V A L _ D E C --
6-- --
7-- S p e c --
8-- --
748086b7 9-- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
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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- --
748086b7 13-- ware Foundation; either version 3, or (at your option) any later ver- --
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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 --
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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/>. --
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26-- --
27-- GNAT was originally developed by the GNAT team at New York University. --
71ff80dc 28-- Extensive contributions were provided by Ada Core Technologies Inc. --
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29-- --
30------------------------------------------------------------------------------
31
32-- This package contains routines for scanning decimal values where the size
33-- of the type is no greater than Standard.Integer'Size, for use in Text_IO.
34-- Decimal_IO, and the Value attribute for such decimal types.
35
36package System.Val_Dec is
009186e0 37 pragma Pure;
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38
39 function Scan_Decimal
40 (Str : String;
d90e94c7 41 Ptr : not null access Integer;
cacbc350 42 Max : Integer;
9de61fcb 43 Scale : Integer) return Integer;
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44 -- This function scans the string starting at Str (Ptr.all) for a valid
45 -- real literal according to the syntax described in (RM 3.5(43)). The
46 -- substring scanned extends no further than Str (Max). There are three
47 -- cases for the return:
48 --
49 -- If a valid real literal is found after scanning past any initial spaces,
50 -- then Ptr.all is updated past the last character of the literal (but
51 -- trailing spaces are not scanned out). The value returned is the value
52 -- Integer'Integer_Value (decimal-literal-value), using the given Scale
53 -- to determine this value.
54 --
55 -- If no valid real literal is found, then Ptr.all points either to an
56 -- initial non-digit character, or to Max + 1 if the field is all spaces
57 -- and the exception Constraint_Error is raised.
58 --
59 -- If a syntactically valid integer is scanned, but the value is out of
60 -- range, or, in the based case, the base value is out of range or there
61 -- is an out of range digit, then Ptr.all points past the integer, and
62 -- Constraint_Error is raised.
63 --
64 -- Note: these rules correspond to the requirements for leaving the
65 -- pointer positioned in Text_Io.Get
66 --
67 -- Note: if Str is null, i.e. if Max is less than Ptr, then this is a
68 -- special case of an all-blank string, and Ptr is unchanged, and hence
69 -- is greater than Max as required in this case.
70
71 function Value_Decimal (Str : String; Scale : Integer) return Integer;
72 -- Used in computing X'Value (Str) where X is a decimal types whose size
73 -- does not exceed Standard.Integer'Size. Str is the string argument of
74 -- the attribute. Constraint_Error is raised if the string is malformed
75 -- or if the value is out of range, otherwise the value returned is the
76 -- value Integer'Integer_Value (decimal-literal-value), using the given
77 -- Scale to determine this value.
78
79end System.Val_Dec;