| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . V A L U E _ F -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2020-2022, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package contains the routines for supporting the Value attribute for |
| -- ordinary fixed point types whose Small is the ratio of two Int values, and |
| -- also for conversion operations required in Text_IO.Fixed_IO for such types. |
| |
| generic |
| |
| type Int is range <>; |
| |
| type Uns is mod <>; |
| |
| with procedure Scaled_Divide |
| (X, Y, Z : Int; |
| Q, R : out Int; |
| Round : Boolean); |
| |
| package System.Value_F is |
| pragma Preelaborate; |
| |
| function Scan_Fixed |
| (Str : String; |
| Ptr : not null access Integer; |
| Max : Integer; |
| Num : Int; |
| Den : Int) return Int; |
| -- This function scans the string starting at Str (Ptr.all) for a valid |
| -- real literal according to the syntax described in (RM 3.5(43)). The |
| -- substring scanned extends no further than Str (Max). There are three |
| -- cases for the return: |
| -- |
| -- If a valid real literal is found after scanning past any initial spaces, |
| -- then Ptr.all is updated past the last character of the literal (but |
| -- trailing spaces are not scanned out). The value returned is the value |
| -- Int'Integer_Value (decimal-literal-value), using the given Num/Den to |
| -- determine this value. |
| -- |
| -- If no valid real literal is found, then Ptr.all points either to an |
| -- initial non-digit character, or to Max + 1 if the field is all spaces |
| -- and the exception Constraint_Error is raised. |
| -- |
| -- If a syntactically valid integer is scanned, but the value is out of |
| -- range, or, in the based case, the base value is out of range or there |
| -- is an out of range digit, then Ptr.all points past the integer, and |
| -- Constraint_Error is raised. |
| -- |
| -- Note: these rules correspond to the requirements for leaving the |
| -- pointer positioned in Text_Io.Get |
| -- |
| -- Note: if Str is null, i.e. if Max is less than Ptr, then this is a |
| -- special case of an all-blank string, and Ptr is unchanged, and hence |
| -- is greater than Max as required in this case. |
| |
| function Value_Fixed |
| (Str : String; |
| Num : Int; |
| Den : Int) return Int; |
| -- Used in computing X'Value (Str) where X is an ordinary fixed-point type. |
| -- Str is the string argument of the attribute. Constraint_Error is raised |
| -- if the string is malformed or if the value is out of range of Int (not |
| -- the range of the fixed-point type, which must be done by the caller). |
| -- Otherwise the value returned is the value Int'Integer_Value |
| -- (decimal-literal-value), using Small Num/Den to determine this value. |
| |
| end System.Value_F; |
