| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . V A L U E _ N -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2021, 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 is used to compute the Value attribute for enumeration types |
| -- other than those in packages Standard and System. See unit Exp_Imgv for |
| -- details of the format of constructed image tables. |
| |
| generic |
| |
| type Index_Type is range <>; |
| |
| package System.Value_N is |
| pragma Preelaborate; |
| |
| type Hash_Function_Ptr is access function (S : String) return Natural; |
| |
| function Value_Enumeration |
| (Names : String; |
| Indexes : System.Address; |
| Hash : Hash_Function_Ptr; |
| Num : Natural; |
| Str : String) |
| return Natural with Inline; |
| -- Used to compute Enum'Value (Str) where Enum is some enumeration type |
| -- other than those defined in package Standard. Names is a string with |
| -- a lower bound of 1 containing the characters of all the enumeration |
| -- literals concatenated together in sequence. Indexes is the address |
| -- of an array of type array (0 .. N) of Index_Type, where N is the |
| -- number of enumeration literals in the type. The Indexes values are |
| -- the starting subscript of each enumeration literal, indexed by Pos |
| -- values, with an extra entry at the end containing Names'Length + 1. |
| -- The parameter Hash is a (perfect) hash function for Names and Indexes. |
| -- The parameter Num is the value N - 1 (i.e. Enum'Pos (Enum'Last)). |
| -- The reason that Indexes is passed by address is that the actual type |
| -- is created on the fly by the expander. |
| -- |
| -- Str is the argument of the attribute function, and may have leading |
| -- and trailing spaces, and letters can be upper or lower case or mixed. |
| -- If the image is found in Names, then the corresponding Pos value is |
| -- returned. If not, Constraint_Error is raised. |
| |
| function Valid_Value_Enumeration |
| (Names : String; |
| Indexes : System.Address; |
| Hash : Hash_Function_Ptr; |
| Num : Natural; |
| Str : String) |
| return Boolean with Inline; |
| -- Returns True if Str is a valid Image of some enumeration literal, False |
| -- otherwise. That is, returns False if and only if Value_Enumeration would |
| -- raise Constraint_Error. The parameters have the same meaning as for |
| -- Value_Enumeration. |
| |
| end System.Value_N; |
