Mega Code Archive
Class Instance Counter
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Title: Class Instance Counter
Question: I want show you how to implement an instance counter in Delphi Object Pascal. It is possible to use it to find memory leaks. See the code and, please, send me suggestions.
P.S:
Sorry for my (bad) english...
Answer:
// --- Instance Counter Unit ---
unit Unit1;
interface
uses
SysUtils, Classes;
type
TOperation = (ooAdd, ooRemove, ooExtract);
TInstanceCounter = class
private
{ Private declarations }
function GetCount: Cardinal;
class function InstanceManager(value: TOperation): Cardinal;
protected
{ Protected declarations }
public
{ Public declarations }
constructor Create;
destructor Destroy; override;
published
{ Published declarations }
property InstanceCount: Cardinal read GetCount;
end;
implementation
// --- TInstanceCounter -------------------------------------------------------
constructor TInstanceCounter.Create;
begin
inherited;
InstanceManager(ooAdd);
end;
destructor TInstanceCounter.Destroy;
begin
InstanceManager(ooRemove);
inherited Destroy;
end;
function TInstanceCounter.GetCount: Cardinal;
begin
Result := InstanceManager(ooExtract);
end;
{$J+}
class function TInstanceCounter.InstanceManager(value: TOperation): cardinal;
const
X: Cardinal = 0;
begin
if value = ooAdd then
Inc(X)
else if value = ooRemove then
begin
if X 0 then
Dec(X);
end;
Result := X;
end;
{$J-}
initialization
//
finalization
if TInstanceCounter.InstanceManager 0 then
Beep;
end.
// ---------------------------------------
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