Ben Scott writes: > We keep seeing the recommendation to use highly-portable encodings > when possible, e.g., ASCII, or some kind of self-descriptive encoding. > Which I fully agree is a very good idea. > > But assume for the sake of discussion we want to keep overhead as > low as possible for performance reasons, and "wait until computers get > faster" isn't a practical solution. What techniques, best practices, > de facto standards, popular libraries, etc., exist for this sort of > thing?
If somebody were to disallow me from suggesting a solution to this problem which relied upon ASCII text, then my next proposed solution would be to use ASN.1 with either a DER or PER encoding. If you think that this is a better solution, then more power to you. > Obviously, putting unsigned integers into "network byte order" for > transmission is one such best practice. > > What about signed integers? Can one expect hton*() and ntoh*() to > work for signed integers as well? IIRC, most machines store signed > ints in two's-complement format, which I think would survive and work > properly if swapped to compensate for an endianess change, but I'm not > sure. Yes, htonl() et al. work just fine with two's compliment machines. IIRC, I haven't worked with a machine that didn't use a two's compliment as its internal representation for integers in over two decades, so I really am not enthusiastic about investigating this particular problem. Yeah, yeah, somebody might be tempted at this point to chirp up with a statement like "but I used to use the lovely Frobozz 9000 machine (which used one's-compliment) back in the 80's to perform ray-tracing and accounting functions!!!", to which I will pre-emptively respond "Yawn.". > What about floating point? ASN.1 and BER/PER encoding... Regards, --kevin -- GnuPG ID: B280F24E God, I loved that Pontiac. alumni.unh.edu!kdc -- Tom Waits http://kdc-blog.blogspot.com/ _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
