

{$mode objfpc}

type
   tbaseclass = class
     x : longint;
     class procedure virtual_class_method; virtual;
     class procedure call_virtual_class_method;
     class function getsize : longint;
     procedure check_size;
   end;

   tderivedclass = class(tbaseclass)
     y : longint;
     class procedure virtual_class_method; override;
   end;

const
  tbasecalled : boolean = false;
  tderivedcalled : boolean = false;
  has_error : boolean = false;
  expected_size_for_tbaseclass = sizeof(pointer) + sizeof(longint);
  expected_size_for_tderivedclass = sizeof(pointer) + 2*sizeof(longint);

var
  basesize : longint;
  derivedsize : longint;

procedure tbaseclass.virtual_class_method;

begin
  Writeln('Calling tbase class class method');
  tbasecalled:=true;
  if sizeof(self)<>basesize then
    begin
      has_error:=true;
      Writeln('Error with sizeof');
    end;
end;

function tbaseclass.getsize : longint;
begin
  getsize:=sizeof(self);
end;

procedure tbaseclass.check_size;
begin
  if sizeof(self)<>getsize then
    begin
      Writeln('Compiler creates garbage');
      has_error:=true;
    end;
end;

class procedure tbaseclass.call_virtual_class_method;
begin
  virtual_class_method;
  if getsize<>sizeof(self) then
    begin
      Writeln('Compiler creates garbage');
      has_error:=true;
    end;
end;

procedure tderivedclass.virtual_class_method;

begin
  Writeln('Calling tderived class class method');
  tderivedcalled:=true;
  if sizeof(self)<>derivedsize then
    begin
      has_error:=true;
      Writeln('Error with sizeof');
    end;
end;

procedure reset_booleans;
begin
  tbasecalled:=false;
  tderivedcalled:=false;
end;

var
  c1,cb : tbaseclass;
  cd : tderivedclass;
  cc : class of tbaseclass;

begin
 cb:=tbaseclass.create;
 cd:=tderivedclass.create;
 c1:=tbaseclass.create;

 basesize:=sizeof(cb);
 Writeln('Sizeof(cb)=',basesize);
 if basesize<>expected_size_for_tbaseclass then
   Writeln('not the expected size : ',expected_size_for_tbaseclass);
 Writeln('cb.InstanceSize=',Cb.InstanceSize);
 if cb.InstanceSize<>expected_size_for_tbaseclass then
   Writeln('not the expected size : ',expected_size_for_tbaseclass);
 Writeln('Tbaseclass.InstanceSize=',Tbaseclass.InstanceSize);
 if TBaseClass.InstanceSize<>expected_size_for_tbaseclass then
   Writeln('not the expected size : ',expected_size_for_tbaseclass);

 derivedsize:=sizeof(cd);
 Writeln('Sizeof(ct)=',derivedsize);
 if derivedsize<>expected_size_for_tderivedclass then
   Writeln('not the expected size : ',expected_size_for_tderivedclass);

 cb.check_size;
 cd.check_size;

 tbaseclass.virtual_class_method;
 if not tbasecalled then
   has_error:=true;
 reset_booleans;

 tbaseclass.call_virtual_class_method;
 if not tbasecalled then
   has_error:=true;
 reset_booleans;

 tderivedclass.virtual_class_method;
 if not tderivedcalled then
   has_error:=true;
 reset_booleans;

 tderivedclass.call_virtual_class_method;
 if not tderivedcalled then
   has_error:=true;
 reset_booleans;

 c1.virtual_class_method;
 if not tbasecalled then
   has_error:=true;
 reset_booleans;

 c1.call_virtual_class_method;
 if not tbasecalled then
   has_error:=true;
 reset_booleans;

 c1.destroy;

 c1:=tderivedclass.create;

 c1.virtual_class_method;
 if not tderivedcalled then
   has_error:=true;
 reset_booleans;

 c1.call_virtual_class_method;
 if not tderivedcalled then
   has_error:=true;
 reset_booleans;

 c1.destroy;

 cc:=tbaseclass;

 cc.virtual_class_method;
 if not tbasecalled then
   has_error:=true;
 reset_booleans;

 cc.call_virtual_class_method;
 if not tbasecalled then
   has_error:=true;
 reset_booleans;

 cc:=tderivedclass;

 cc.virtual_class_method;
 if not tderivedcalled then
   has_error:=true;
 reset_booleans;

 cc.call_virtual_class_method;
 if not tderivedcalled then
   has_error:=true;
 reset_booleans;

 Writeln('Szeof(cc)=',sizeof(cc));

 if has_error then
   begin
     Writeln('Error with class methods');
     halt(1);
   end;

end.
