Dear Nat and boosters Ooops, rereading my message, I simply cannot figure out the reason why I wrote such a stupid thing! You are absolutely right and your calculation of this factor ~<2 rather than 6 is ok. So this hypothetical system is still bad, but not as bad as I claimed before. Thank you for the fix. And sorry for the trouble ("Au temps pour moi!"). regards frc --
I do understand that this issue has already been debated to the point of a new implementation. I just want to ask about a side point I didn't quite understand earlier.
François Mauger wrote:
In fact, since we are only rendering the characters "[-+e.0-9]" we could use a modified BCD or other compressed format to provide the compression that is typically what people assume in binary formats.
ok this is only a set of 14 glyphs so it could be hosted via short ints (with 2 bits unused)
? I think each of 14 glyphs could be represented in 4 bits, with 2 bit patterns left over.
consider a typical float (relative precision ~1e-7). If one need to store pi as +0.3141592e+01 (ASCII) it is 14 characters (only 11 is one saves leading'+' and exponent '+0' chars for >0 mantissa and exponent) that could be serialized using 14/11 shorts, so this is 28/22 bytes. This has to be compared with 4 bytes for floats!
It seems to me that 14 characters in the constrained glyph set could be represented with 14 4-bit "nybbles," or 7 bytes.
It's still worse than 4 bytes, but by a factor < 2 rather than ~6.
Please forgive me if I've misunderstood you. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Francois Mauger Laboratoire de Physique Corpusculaire de Caen et Universite de Caen ENSICAEN - 6, Boulevard du Marechal Juin, 14050 CAEN Cedex, FRANCE e-mail: mauger@lpccaen.in2p3.fr tel.: (0/+33) 2 31 45 25 12 fax: (0/+33) 2 31 45 25 49