UrlDecode() in TSQL

T-SQL UrlDecode

CREATE FUNCTION dbo.UrlDecode(@url varchar(3072))
RETURNS varchar(3072)
AS
BEGIN
DECLARE @count int, @c char(1), @cenc char(2), @i int, @urlReturn
varchar(3072)
SET @count = Len(@url)
SET @i = 1
SET @urlReturn = ''
WHILE (@i <= @count)
BEGIN
SET @c = substring(@url, @i, 1)
IF @c LIKE '[!%]' ESCAPE '!'
BEGIN
SET @cenc = substring(@url, @i + 1, 2)
SET @c = CHAR(CASE WHEN SUBSTRING(@cenc, 1, 1) LIKE '[0-9]'
THEN CAST(SUBSTRING(@cenc, 1, 1) as int)
ELSE CAST(ASCII(UPPER(SUBSTRING(@cenc, 1, 1)))-55 as int)
END * 16 +
CASE WHEN SUBSTRING(@cenc, 2, 1) LIKE '[0-9]'
THEN CAST(SUBSTRING(@cenc, 2, 1) as int)
ELSE CAST(ASCII(UPPER(SUBSTRING(@cenc, 2, 1)))-55 as int)
END)
SET @urlReturn = @urlReturn + @c
SET @i = @i + 2

END
ELSE

BEGIN
SET @urlReturn = @urlReturn + @c

END
SET @i = @i +1
END
RETURN @urlReturn
END

GO