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------------------------------------------------------------------------------
-- --
-- GNAT RUNTIME COMPONENTS --
-- --
-- I N T E R F A C E S . C P P --
-- --
-- B o d y --
-- --
-- $Revision: 1.12 $ --
-- --
-- Copyright (C) 1992,1993,1994,1995,1996 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 2, 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 COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
with Ada.Tags; use Ada.Tags;
with Interfaces.C; use Interfaces.C;
with System; use System;
with System.Storage_Elements; use System.Storage_Elements;
with Unchecked_Conversion;
package body Interfaces.CPP is
subtype Cstring is String (Positive);
type Cstring_Ptr is access all Cstring;
type Tag_Table is array (Natural range <>) of Vtable_Ptr;
type Type_Specific_Data is record
Idepth : Natural;
Expanded_Name : Cstring_Ptr;
External_Tag : Cstring_Ptr;
HT_Link : Tag;
Ancestor_Tags : Tag_Table (Natural);
end record;
type Vtable_Entry is record
Delta1 : C.Short;
Index : C.Short;
Pfn : System.Address;
end record;
type Type_Specific_Data_Ptr is access all Type_Specific_Data;
type Vtable_Entry_Array is array (Positive range <>) of Vtable_Entry;
type VTable is record
Unused1 : C.Short;
Unused2 : C.Short;
TSD : Type_Specific_Data_Ptr;
Prims_Ptr : Vtable_Entry_Array (Positive);
end record;
--------------------------------------------------------
-- Unchecked Conversions for Tag, Vtable_Ptr, and TSD --
--------------------------------------------------------
function To_Type_Specific_Data_Ptr is
new Unchecked_Conversion (Address, Type_Specific_Data_Ptr);
function To_Address is new Unchecked_Conversion (Vtable_Ptr, Address);
function To_Address is
new Unchecked_Conversion (Type_Specific_Data_Ptr, Address);
function To_Vtable_Ptr is new Unchecked_Conversion (Tag, Vtable_Ptr);
function To_Tag is new Unchecked_Conversion (Vtable_Ptr, Tag);
---------------------------------------------
-- Unchecked Conversions for String Fields --
---------------------------------------------
function To_Cstring_Ptr is
new Unchecked_Conversion (Address, Cstring_Ptr);
function To_Address is
new Unchecked_Conversion (Cstring_Ptr, Address);
-----------------------
-- Local Subprograms --
-----------------------
function Length (Str : Cstring_Ptr) return Natural;
-- Length of string represented by the given pointer (treating the
-- string as a C-style string, which is Nul terminated).
--------------------
-- Displaced_This --
--------------------
function Displaced_This
(Current_This : System.Address;
Vptr : Vtable_Ptr;
Position : Positive)
return System.Address
is
begin
return Current_This
+ Storage_Offset (Vptr.Prims_Ptr (Position).Delta1);
end Displaced_This;
-----------------------
-- CPP_CW_Membership --
-----------------------
function CPP_CW_Membership
(Obj_Tag : Vtable_Ptr;
Typ_Tag : Vtable_Ptr)
return Boolean
is
Pos : constant Integer := Obj_Tag.TSD.Idepth - Typ_Tag.TSD.Idepth;
begin
return Pos >= 0 and then Obj_Tag.TSD.Ancestor_Tags (Pos) = Typ_Tag;
end CPP_CW_Membership;
---------------------------
-- CPP_Get_Expanded_Name --
---------------------------
function CPP_Get_Expanded_Name (T : Vtable_Ptr) return Address is
begin
return To_Address (T.TSD.Expanded_Name);
end CPP_Get_Expanded_Name;
--------------------------
-- CPP_Get_External_Tag --
--------------------------
function CPP_Get_External_Tag (T : Vtable_Ptr) return Address is
begin
return To_Address (T.TSD.External_Tag);
end CPP_Get_External_Tag;
-------------------------------
-- CPP_Get_Inheritance_Depth --
-------------------------------
function CPP_Get_Inheritance_Depth (T : Vtable_Ptr) return Natural is
begin
return T.TSD.Idepth;
end CPP_Get_Inheritance_Depth;
-------------------------
-- CPP_Get_Prim_Op_Address --
-------------------------
function CPP_Get_Prim_Op_Address
(T : Vtable_Ptr;
Position : Positive)
return Address is
begin
return T.Prims_Ptr (Position).Pfn;
end CPP_Get_Prim_Op_Address;
-----------------
-- CPP_Get_TSD --
-----------------
function CPP_Get_TSD (T : Vtable_Ptr) return Address is
begin
return To_Address (T.TSD);
end CPP_Get_TSD;
--------------------
-- CPP_Inherit_DT --
--------------------
procedure CPP_Inherit_DT
(Old_T : Vtable_Ptr;
New_T : Vtable_Ptr;
Entry_Count : Natural)
is
begin
if Old_T /= null then
New_T.Prims_Ptr (1 .. Entry_Count)
:= Old_T.Prims_Ptr (1 .. Entry_Count);
end if;
end CPP_Inherit_DT;
---------------------
-- CPP_Inherit_TSD --
---------------------
procedure CPP_Inherit_TSD
(Old_TSD : Address;
New_Tag : Vtable_Ptr)
is
TSD : constant Type_Specific_Data_Ptr
:= To_Type_Specific_Data_Ptr (Old_TSD);
New_TSD : Type_Specific_Data renames New_Tag.TSD.all;
begin
if TSD /= null then
New_TSD.Idepth := TSD.Idepth + 1;
New_TSD.Ancestor_Tags (1 .. New_TSD.Idepth)
:= TSD.Ancestor_Tags (0 .. TSD.Idepth);
else
New_TSD.Idepth := 0;
end if;
New_TSD.Ancestor_Tags (0) := New_Tag;
end CPP_Inherit_TSD;
---------------------------
-- CPP_Set_Expanded_Name --
---------------------------
procedure CPP_Set_Expanded_Name (T : Vtable_Ptr; Value : Address) is
begin
T.TSD.Expanded_Name := To_Cstring_Ptr (Value);
end CPP_Set_Expanded_Name;
--------------------------
-- CPP_Set_External_Tag --
--------------------------
procedure CPP_Set_External_Tag (T : Vtable_Ptr; Value : Address) is
begin
T.TSD.External_Tag := To_Cstring_Ptr (Value);
end CPP_Set_External_Tag;
-------------------------------
-- CPP_Set_Inheritance_Depth --
-------------------------------
procedure CPP_Set_Inheritance_Depth
(T : Vtable_Ptr;
Value : Natural)
is
begin
T.TSD.Idepth := Value;
end CPP_Set_Inheritance_Depth;
-----------------------------
-- CPP_Set_Prim_Op_Address --
-----------------------------
procedure CPP_Set_Prim_Op_Address
(T : Vtable_Ptr;
Position : Positive;
Value : Address)
is
begin
T.Prims_Ptr (Position).Pfn := Value;
end CPP_Set_Prim_Op_Address;
-----------------
-- CPP_Set_TSD --
-----------------
procedure CPP_Set_TSD (T : Vtable_Ptr; Value : Address) is
begin
T.TSD := To_Type_Specific_Data_Ptr (Value);
end CPP_Set_TSD;
-------------------
-- Expanded_Name --
-------------------
function Expanded_Name (T : Vtable_Ptr) return String is
Result : Cstring_Ptr := T.TSD.Expanded_Name;
begin
return Result (1 .. Length (Result));
end Expanded_Name;
------------------
-- External_Tag --
------------------
function External_Tag (T : Vtable_Ptr) return String is
Result : Cstring_Ptr := T.TSD.External_Tag;
begin
return Result (1 .. Length (Result));
end External_Tag;
------------
-- Length --
------------
function Length (Str : Cstring_Ptr) return Natural is
Len : Integer := 1;
begin
while Str (Len) /= Ascii.Nul loop
Len := Len + 1;
end loop;
return Len - 1;
end Length;
end Interfaces.CPP;
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