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-- -- 9-- Copyright (C) 1992-2009, 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 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 37 pragma Pure; 38 39 function Scan_Decimal 40 (Str : String; 41 Ptr : not null access Integer; 42 Max : Integer; 43 Scale : Integer) return 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 -- 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; 80