On Sun, Sep 24, 2006 at 05:07:23PM +0900, Robert Marlow wrote:
Erk, I just realised this patch is completely wrong since the HostAddress will be totally different depending on the endianness of the platform.
I was thinking about it before. As of now, Network libraries just put bits in network order into values of type HostAddress = Word32. But Word32 is interpreted in host order by Haskell, so the same IP address will be seen as a different number on little and big endian platforms. The best would be to have an endianness independent representation for IP4 addresses, by converting IP addresses to host order. This way things are simple - the most significant octet of IP address with be the most significant 8-bits of HostAddress, etc. Conversion to/from network order could be done around calls to various system calls. Yes, it adds an (small) additional cost (on little endian machines), but I think it's worth it. With current design you sometimes can't avoid impure and/or inelegant code. Best regards Tomasz