| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . V A L _ B O O L -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2022, 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- Preconditions in this unit are meant for analysis only, not for run-time |
| -- checking, so that the expected exceptions are raised. This is enforced by |
| -- setting the corresponding assertion policy to Ignore. Postconditions and |
| -- contract cases should not be executed at runtime as well, in order not to |
| -- slow down the execution of these functions. |
| |
| pragma Assertion_Policy (Pre => Ignore, |
| Post => Ignore, |
| Contract_Cases => Ignore, |
| Ghost => Ignore); |
| |
| with System.Val_Util; |
| |
| package System.Val_Bool |
| with SPARK_Mode |
| is |
| pragma Preelaborate; |
| |
| function Is_Boolean_Image_Ghost (Str : String) return Boolean is |
| (not System.Val_Util.Only_Space_Ghost (Str, Str'First, Str'Last) |
| and then |
| (declare |
| F : constant Positive := System.Val_Util.First_Non_Space_Ghost |
| (Str, Str'First, Str'Last); |
| begin |
| (F <= Str'Last - 3 |
| and then Str (F) in 't' | 'T' |
| and then Str (F + 1) in 'r' | 'R' |
| and then Str (F + 2) in 'u' | 'U' |
| and then Str (F + 3) in 'e' | 'E' |
| and then |
| (if F + 3 < Str'Last then |
| System.Val_Util.Only_Space_Ghost (Str, F + 4, Str'Last))) |
| or else |
| (F <= Str'Last - 4 |
| and then Str (F) in 'f' | 'F' |
| and then Str (F + 1) in 'a' | 'A' |
| and then Str (F + 2) in 'l' | 'L' |
| and then Str (F + 3) in 's' | 'S' |
| and then Str (F + 4) in 'e' | 'E' |
| and then |
| (if F + 4 < Str'Last then |
| System.Val_Util.Only_Space_Ghost (Str, F + 5, Str'Last))))) |
| with |
| Ghost; |
| -- Ghost function that returns True iff Str is the image of a boolean, that |
| -- is "true" or "false" in any capitalization, possibly surounded by space |
| -- characters. |
| |
| function Value_Boolean (Str : String) return Boolean |
| with |
| Pre => Is_Boolean_Image_Ghost (Str), |
| Post => |
| Value_Boolean'Result = |
| (Str (System.Val_Util.First_Non_Space_Ghost |
| (Str, Str'First, Str'Last)) in 't' | 'T'); |
| -- Computes Boolean'Value (Str) |
| |
| end System.Val_Bool; |
