Alphanumeric and Special Character Validation- New

Create function fn_ValidateString
(
--RETURN 1 - VALIDE
--       0 - FAILURE
@InputString Varchar(25),
@Type int -- =0 allowes only ALPHANUMERIC, <>0 ALPHANUMERIC AND @  (  ) _ -
)
RETURNS int
AS
/*
    Author : Ramesh Kondaparthy
    Version: 1.0
    Changes Made: Replaced table variable with Case statements.

*/BEGIN
--SET NOCOUNT ON
DECLARE @Status int
SET @Status=0

DECLARE @Source Varchar(25)
DECLARE @Character CHAR(1)

DECLARE @rowCnt CHAR(1)

SET @Source=@InputString
SET @Character =''

SET @Source = LTRIM(RTRIM(@Source))
DECLARE @MyTable Table (Val char(1))

DECLARE @Pos  INT
DECLARE @Len INT
SET @Pos = 0
SET @Len = 0

DECLARE @Valide int


SET @Pos = LEN(@Source)
SET @Len = @Pos

WHILE @Pos > 0
BEGIN
SET @Character = LEFT(@Source,1)

IF @Type=0
Begin
SELECT @Valide=
CASE 
WHEN @Character like '[A-Z]' OR @Character like '[a-z]'  OR @Character like '[0-9]'  THEN 0
ELSE 1
END
End
Else
Begin
SELECT @Valide=
CASE 
WHEN (@Character like '[A-Z]' OR @Character like '[a-z]'  OR @Character like '[0-9]'  
OR @Character = '@'   OR @Character = '('   OR @Character = ')'   
OR @Character = '-'  OR @Character = '_' )   THEN 0
  ELSE 1
END
End
IF @Valide = 1 
Begin
Break
End
Else

Begin
SET @Pos = @Pos - 1
SET @Source = RIGHT(@Source, @Pos)
End

END
IF @Pos=0 
SET @Status  = 0
ELSE
SET @Status  = 1

RETURN @Status  


End