unit HKSafeForm;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  typinfo;

type
  TChange = Procedure of object;

  THKSafeForm = class(TComponent)
  private
   FCRC32 : Integer;
   FOnTamper : TChange;
   procedure ReadCRC(Reader : TReader);
   procedure WriteCRC(Writer : TWriter);
   Function GetCRC : Integer;
   FUNCTION UpdCrc32(cp: BYTE; crc: LONGINT): LONGINT;
   function GetCRC32(Data: Pointer; DataLength: Integer): LongInt;
   Function AppWindowHook(var message : TMessage) : Boolean;
  protected
   Procedure DefineProperties(Filer : TFiler); override;
  public
   Procedure Check;
   Constructor Create(AOwner : TComponent); override;
  published
   property OnDirty : TChange read FOnTamper write FOnTamper;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Haka', [THKSafeForm]);
end;

CONST crc_32_tab: ARRAY[0..255] OF LongInt = (
$00000000, $77073096, $ee0e612c, $990951ba, $076dc419, $706af48f, $e963a535, $9e6495a3,
$0edb8832, $79dcb8a4, $e0d5e91e, $97d2d988, $09b64c2b, $7eb17cbd, $e7b82d07, $90bf1d91,
$1db71064, $6ab020f2, $f3b97148, $84be41de, $1adad47d, $6ddde4eb, $f4d4b551, $83d385c7,
$136c9856, $646ba8c0, $fd62f97a, $8a65c9ec, $14015c4f, $63066cd9, $fa0f3d63, $8d080df5,
$3b6e20c8, $4c69105e, $d56041e4, $a2677172, $3c03e4d1, $4b04d447, $d20d85fd, $a50ab56b,
$35b5a8fa, $42b2986c, $dbbbc9d6, $acbcf940, $32d86ce3, $45df5c75, $dcd60dcf, $abd13d59,
$26d930ac, $51de003a, $c8d75180, $bfd06116, $21b4f4b5, $56b3c423, $cfba9599, $b8bda50f,
$2802b89e, $5f058808, $c60cd9b2, $b10be924, $2f6f7c87, $58684c11, $c1611dab, $b6662d3d,
$76dc4190, $01db7106, $98d220bc, $efd5102a, $71b18589, $06b6b51f, $9fbfe4a5, $e8b8d433,
$7807c9a2, $0f00f934, $9609a88e, $e10e9818, $7f6a0dbb, $086d3d2d, $91646c97, $e6635c01,
$6b6b51f4, $1c6c6162, $856530d8, $f262004e, $6c0695ed, $1b01a57b, $8208f4c1, $f50fc457,
$65b0d9c6, $12b7e950, $8bbeb8ea, $fcb9887c, $62dd1ddf, $15da2d49, $8cd37cf3, $fbd44c65,
$4db26158, $3ab551ce, $a3bc0074, $d4bb30e2, $4adfa541, $3dd895d7, $a4d1c46d, $d3d6f4fb,
$4369e96a, $346ed9fc, $ad678846, $da60b8d0, $44042d73, $33031de5, $aa0a4c5f, $dd0d7cc9,
$5005713c, $270241aa, $be0b1010, $c90c2086, $5768b525, $206f85b3, $b966d409, $ce61e49f,
$5edef90e, $29d9c998, $b0d09822, $c7d7a8b4, $59b33d17, $2eb40d81, $b7bd5c3b, $c0ba6cad,
$edb88320, $9abfb3b6, $03b6e20c, $74b1d29a, $ead54739, $9dd277af, $04db2615, $73dc1683,
$e3630b12, $94643b84, $0d6d6a3e, $7a6a5aa8, $e40ecf0b, $9309ff9d, $0a00ae27, $7d079eb1,
$f00f9344, $8708a3d2, $1e01f268, $6906c2fe, $f762575d, $806567cb, $196c3671, $6e6b06e7,
$fed41b76, $89d32be0, $10da7a5a, $67dd4acc, $f9b9df6f, $8ebeeff9, $17b7be43, $60b08ed5,
$d6d6a3e8, $a1d1937e, $38d8c2c4, $4fdff252, $d1bb67f1, $a6bc5767, $3fb506dd, $48b2364b,
$d80d2bda, $af0a1b4c, $36034af6, $41047a60, $df60efc3, $a867df55, $316e8eef, $4669be79,
$cb61b38c, $bc66831a, $256fd2a0, $5268e236, $cc0c7795, $bb0b4703, $220216b9, $5505262f,
$c5ba3bbe, $b2bd0b28, $2bb45a92, $5cb36a04, $c2d7ffa7, $b5d0cf31, $2cd99e8b, $5bdeae1d,
$9b64c2b0, $ec63f226, $756aa39c, $026d930a, $9c0906a9, $eb0e363f, $72076785, $05005713,
$95bf4a82, $e2b87a14, $7bb12bae, $0cb61b38, $92d28e9b, $e5d5be0d, $7cdcefb7, $0bdbdf21,
$86d3d2d4, $f1d4e242, $68ddb3f8, $1fda836e, $81be16cd, $f6b9265b, $6fb077e1, $18b74777,
$88085ae6, $ff0f6a70, $66063bca, $11010b5c, $8f659eff, $f862ae69, $616bffd3, $166ccf45,
$a00ae278, $d70dd2ee, $4e048354, $3903b3c2, $a7672661, $d06016f7, $4969474d, $3e6e77db,
$aed16a4a, $d9d65adc, $40df0b66, $37d83bf0, $a9bcae53, $debb9ec5, $47b2cf7f, $30b5ffe9,
$bdbdf21c, $cabac28a, $53b39330, $24b4a3a6, $bad03605, $cdd70693, $54de5729, $23d967bf,
$b3667a2e, $c4614ab8, $5d681b02, $2a6f2b94, $b40bbe37, $c30c8ea1, $5a05df1b, $2d02ef8d
);

{ THKSafeForm }

FUNCTION THKSafeForm.UpdCrc32(cp: BYTE; crc: LONGINT) : LONGINT;
BEGIN
  UpdCrc32:= crc_32_tab[BYTE(crc XOR LONGINT(cp))] XOR ((crc SHR 8) AND $FFFFFF);
END;

function THKSafeForm.GetCRC32(Data: Pointer; DataLength: Integer) : LongInt;
type
  TByteArray = Array[1..MaxInt] of Byte;
var
  i: Integer;
begin
  Result:= -1;
  for i:= 1 to DataLength do Result:= UpdCRC32(TByteArray(Data^)[i], Result);
  Result:= not Result;
end;

procedure THKSafeForm.Check;
begin
 if FCRC32<>GetCRC then
 begin
  if assigned(FOnTamper)
   then FOnTamper
   else begin
    TForm(Owner).OnCloseQuery:=nil;
    application.terminate;
   end;
 end;
end;

procedure THKSafeForm.DefineProperties(Filer: TFiler);
begin
 inherited defineproperties(filer);
 filer.DefineProperty('p',readCRC,writeCRC,true)
end;

function THKSafeForm.GetCRC: Integer;
var
 c:integer;
 s:string;
 PropInfo : PPropInfo;
 TypeInfo : pTypeInfo;
begin
 with TForm(owner) do
 for c:=0 to Componentcount-1 do
 begin
  TypeInfo:=components[c].classinfo;
  PropInfo:=GetPropInfo(TypeInfo,'Caption');
  if propinfo<>nil then s:=s+GetStrProp(components[c],propinfo);
 end;
 if length(s)>0
  then result:=GetCRC32(pchar(s),length(s))
  else result:=0;
end;

procedure THKSafeForm.ReadCRC(Reader: TReader);
begin
 FCRC32:=reader.readinteger;
end;

procedure THKSafeForm.WriteCRC(Writer: TWriter);
begin
 writer.WriteInteger(getcrc);
end;

function THKSafeForm.AppWindowHook(var message: TMessage): Boolean;
begin
 result:=true;
 Application.UnHookMainWindow(AppWindowHook);
 check;
end;

constructor THKSafeForm.Create(AOwner: TComponent);
begin
 inherited create(AOwner);
 if componentstate=[] then
  Application.HookMainWindow(AppWindowHook);
end;

end.
