------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             E X P _ I M G V                              --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 2000-2021, 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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  Expand routines for Image, Value and Width attributes. These are the
--  attributes that make use of enumeration type image tables.

with Types; use Types;

package Exp_Imgv is

   procedure Build_Enumeration_Image_Tables (E : Entity_Id; N : Node_Id);
   --  Build the enumeration image tables for E, which is an enumeration
   --  base type. The node N is the point in the tree where the resulting
   --  declarations are to be inserted.
   --
   --  The form of the tables generated is as follows:
   --
   --    xxxS : constant string (1 .. M) := "chars";
   --    xxxN : constant array (0 .. N) of Index_Type := (i1, i2, .., iN, j);
   --
   --  Here xxxS is a string obtained by concatenating all the names of the
   --  enumeration literals in sequence, representing any wide characters
   --  according to the current wide character encoding method, and with all
   --  letters forced to upper case.
   --
   --  The array xxxN is an array of indexes into xxxS pointing to the start
   --  of each name, with one extra entry at the end, which is the index to
   --  the character just past the end of the last literal, i.e. it is the
   --  length of xxxS + 1. The element type is the shortest of the possible
   --  types that will hold all the values.
   --
   --  For example, for the type
   --
   --     type x is (hello,'!',goodbye);
   --
   --  the generated tables would consist of
   --
   --      xxxS : constant string (1 .. 15) := "hello'!'goodbye";
   --      xxxN : constant array (0 .. 3) of Integer_8 := (1, 6, 9, 16);
   --
   --  Here Integer_8 is used since 16 < 2**(8-1).
   --
   --  If the entity E needs the tables, the necessary declarations are built
   --  and the fields Lit_Strings and Lit_Indexes of E are set to point to the
   --  corresponding entities. If no tables are needed (E is not a user defined
   --  enumeration root type, or pragma Discard_Names is in effect), then the
   --  declarations are not constructed and the fields remain Empty.
   --
   --  If the number of enumeration literals is large enough, a (perfect) hash
   --  function mapping the literals to their position number is also built and
   --  requires additional tables. See the System.Perfect_Hash_Generators unit
   --  for a complete description of this processing.

   procedure Expand_Image_Attribute (N : Node_Id);
   --  This procedure is called from Exp_Attr to expand an occurrence of the
   --  attribute Image.

   procedure Expand_Wide_Image_Attribute (N : Node_Id);
   --  This procedure is called from Exp_Attr to expand an occurrence of the
   --  attribute Wide_Image.

   procedure Expand_Wide_Wide_Image_Attribute (N : Node_Id);
   --  This procedure is called from Exp_Attr to expand an occurrence of the
   --  attribute Wide_Wide_Image.

   procedure Expand_Valid_Value_Attribute (N : Node_Id);
   --  This procedure is called from Exp_Attr to expand an occurrence of the
   --  attribute Valid_Value.

   procedure Expand_Value_Attribute (N : Node_Id);
   --  This procedure is called from Exp_Attr to expand an occurrence of the
   --  attribute Value.

   type Atype is (Normal, Wide, Wide_Wide);
   --  Type of attribute in call to Expand_Width_Attribute

   procedure Expand_Width_Attribute (N : Node_Id; Attr : Atype := Normal);
   --  This procedure is called from Exp_Attr to expand an occurrence of the
   --  attributes Width (Attr = Normal), or Wide_Width (Attr Wide), or
   --  Wide_Wide_Width (Attr = Wide_Wide).

end Exp_Imgv;