RE: instance Show SockAddr
On 15 October 2004 19:44, Tomasz Zielonka wrote:
On Fri, Oct 15, 2004 at 04:24:01PM +0200, Peter Simons wrote:
Hi,
I've found myself needing to show a SockAddr type left and right in my code. Is it possible to add the appropriate definition to Network.Socket? Here is a suggestion:
-- |Split up an 32-bit word in network byte order.
ha2tpl :: HostAddress -> (Int, Int, Int, Int) ha2tpl n = let (b1,n1) = (n .&. 255, n `shiftR` 8) (b2,n2) = (n1 .&. 255, n1 `shiftR` 8) (b3,n3) = (n2 .&. 255, n2 `shiftR` 8) b4 = n3 .&. 255 in (fromEnum b1, fromEnum b2, fromEnum b3, fromEnum b4)
This won't work on big-endian architectures.
If someone has code for a version that works on both endians, now is the time to send it so we can get it into GHC 6.4. Cheers, Simon
Simon Marlow writes:
If someone has code for a version that works on both endians [...]
import Foreign import Network.Socket data Endian = LittleEndian | BigEndian | PDPEndian deriving (Show, Eq) getEndian :: Endian getEndian = unsafePerformIO $ allocaArray (sizeOf (undefined :: Word32)) $ \p -> do let val = 0x01020304 :: Word32 poke p val let p' = castPtr p :: Ptr Word8 val' <- peekArray 4 p' case val' of (0x01:0x02:0x03:0x04:[]) -> return BigEndian (0x04:0x03:0x02:0x01:[]) -> return LittleEndian (0x02:0x01:0x03:0x04:[]) -> return PDPEndian _ -> error "unknown endian" instance Show SockAddr where show (SockAddrUnix str) = str show (SockAddrInet port ha) = shows b1 . ('.':) . shows b2 . ('.':) . shows b3 . ('.':) . shows b4 . (':':) $ show port where (b1,b2,b3,b4) = ha2tpl ha ha2tpl :: HostAddress -> (Int, Int, Int, Int) ha2tpl n = let (b1,n1) = (n .&. 255, n `shiftR` 8) (b2,n2) = (n1 .&. 255, n1 `shiftR` 8) (b3,n3) = (n2 .&. 255, n2 `shiftR` 8) b4 = n3 .&. 255 in case getEndian of BigEndian -> (fromEnum b4, fromEnum b3, fromEnum b2, fromEnum b1) LittleEndian -> (fromEnum b1, fromEnum b2, fromEnum b3, fromEnum b4) PDPEndian -> (fromEnum b4, fromEnum b3, fromEnum b1, fromEnum b2)
participants (2)
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Peter Simons -
Simon Marlow