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) 1992-2018, 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 contains routines for scanning decimal values where the size
33--  of the type is 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_LLD is
37   pragma Pure;
38
39   function Scan_Long_Long_Decimal
40     (Str   : String;
41      Ptr   : not null access Integer;
42      Max   : Integer;
43      Scale : Integer) return Long_Long_Integer;
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   --  Long_Long_Integer'Integer_Value (decimal-literal-value), using the given
53   --  Scale 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_Long_Long_Decimal
72     (Str   : String;
73      Scale : Integer) return Long_Long_Integer;
74   --  Used in computing X'Value (Str) where X is a decimal types whose size
75   --  exceeds Standard.Integer'Size. Str is the string argument of the
76   --  attribute. Constraint_Error is raised if the string is malformed
77   --  or if the value is out of range, otherwise the value returned is the
78   --  value Long_Long_Integer'Integer_Value (decimal-literal-value), using
79   --  the given Scale to determine this value.
80
81end System.Val_LLD;
82