1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                       S Y S T E M . V A L _ L L D                        --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--   Copyright (C) 1992,1993,1994,1995,1996 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 2,  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.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- As a special exception,  if other files  instantiate  generics from this --
23-- unit, or you link  this unit with other files  to produce an executable, --
24-- this  unit  does not  by itself cause  the resulting  executable  to  be --
25-- covered  by the  GNU  General  Public  License.  This exception does not --
26-- however invalidate  any other reasons why  the executable file  might be --
27-- covered by the  GNU Public License.                                      --
28--                                                                          --
29-- GNAT was originally developed  by the GNAT team at  New York University. --
30-- Extensive contributions were provided by Ada Core Technologies Inc.      --
31--                                                                          --
32------------------------------------------------------------------------------
33
34--  This package contains routines for scanning decimal values where the size
35--  of the type is greater than Standard.Integer'Size, for use in Text_IO.
36--  Decimal_IO, and the Value attribute for such decimal types.
37
38package System.Val_LLD is
39pragma Pure (Val_LLD);
40
41   function Scan_Long_Long_Decimal
42     (Str   : String;
43      Ptr   : access Integer;
44      Max   : Integer;
45      Scale : Integer)
46      return  Long_Long_Integer;
47   --  This function scans the string starting at Str (Ptr.all) for a valid
48   --  real literal according to the syntax described in (RM 3.5(43)). The
49   --  substring scanned extends no further than Str (Max). There are three
50   --  cases for the return:
51   --
52   --  If a valid real literal is found after scanning past any initial spaces,
53   --  then Ptr.all is updated past the last character of the literal (but
54   --  trailing spaces are not scanned out). The value returned is the value
55   --  Long_Long_Integer'Integer_Value (decimal-literal-value), using the given
56   --  Scale to determine this value.
57   --
58   --  If no valid real literal is found, then Ptr.all points either to an
59   --  initial non-digit character, or to Max + 1 if the field is all spaces
60   --  and the exception Constraint_Error is raised.
61   --
62   --  If a syntactically valid integer is scanned, but the value is out of
63   --  range, or, in the based case, the base value is out of range or there
64   --  is an out of range digit, then Ptr.all points past the integer, and
65   --  Constraint_Error is raised.
66   --
67   --  Note: these rules correspond to the requirements for leaving the
68   --  pointer positioned in Text_Io.Get
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.
73
74   function Value_Long_Long_Decimal
75     (Str   : String;
76      Scale : Integer)
77      return  Long_Long_Integer;
78   --  Used in computing X'Value (Str) where X is a decimal types whose size
79   --  exceeds Standard.Integer'Size. Str is the string argument of the
80   --  attribute. Constraint_Error is raised if the string is malformed
81   --  or if the value is out of range, otherwise the value returned is the
82   --  value Long_Long_Integer'Integer_Value (decimal-literal-value), using
83   --  the given Scale to determine this value.
84
85end System.Val_LLD;
86