Conversion of varchar IPv4 & IPv6 representations in binary

gistfile1.txt

-- SELECT dbo.fn_ConvertIpAddressToBinary('2002:1ff:6c2::1ff:6c2')
-- SELECT dbo.fn_ConvertIpAddressToBinary('10.4.46.2')
-- SELECT dbo.fn_ConvertIpAddressToBinary('bogus')

ALTER FUNCTION dbo.fn_ConvertIpAddressToBinary
(
     @ipAddress VARCHAR(39)
)
RETURNS BINARY(16) AS
BEGIN
DECLARE
     @bytes BINARY(16), @vbytes VARBINARY(16), @vbzone VARBINARY(2)
     , @colIndex TINYINT, @prevColIndex TINYINT, @parts TINYINT, @limit TINYINT
     , @delim CHAR(1), @token VARCHAR(4), @zone VARCHAR(4)

SELECT
     @delim = '.'
     , @prevColIndex = 0
     , @limit = 4
     , @vbytes = 0x
     , @parts = 0
     , @colIndex = CHARINDEX(@delim, @ipAddress)

IF @colIndex = 0
     BEGIN
           SELECT
                @delim = ':'
                , @limit = 8
                , @colIndex = CHARINDEX(@delim, @ipAddress)
           WHILE @colIndex > 0
                SELECT
                      @parts = @parts + 1
                      , @colIndex = CHARINDEX(@delim, @ipAddress, @colIndex + 1)
           SET @colIndex = CHARINDEX(@delim, @ipAddress)

           IF @colIndex = 0
                RETURN NULL     
     END

SET @ipAddress = @ipAddress + @delim

WHILE @colIndex > 0
     BEGIN
           SET @token = SUBSTRING(@ipAddress, @prevColIndex + 1, @Colindex - @prevColIndex - 1)

           IF @delim = ':'
                BEGIN
                      SET  @zone = RIGHT('0000' + @token, 4)

                      SELECT
                           @vbzone = CAST('' AS XML).value('xs:hexBinary(sql:variable("@zone"))', 'varbinary(2)')
                           , @vbytes = @vbytes + @vbzone

                      IF @token = ''
                           WHILE @parts + 1 < @limit
                                 SELECT
                                      @vbytes = @vbytes + @vbzone
                                      , @parts = @parts + 1
                END
           ELSE
                BEGIN
                      SET @zone = SUBSTRING('' + master.sys.fn_varbintohexstr(CAST(@token AS TINYINT)), 3, 2)

                      SELECT
                           @vbzone = CAST('' AS XML).value('xs:hexBinary(sql:variable("@zone"))', 'varbinary(1)')
                           , @vbytes = @vbytes + @vbzone
                END

           SELECT
                @prevColIndex = @colIndex
                , @colIndex = CHARINDEX(@delim, @ipAddress, @colIndex + 1) 
     END            

SET @bytes =
     CASE @delim
           WHEN ':' THEN @vbytes
           ELSE 0x000000000000000000000000 + @vbytes
     END 

RETURN @bytes

END