Messages in this thread | | | Date | Tue, 21 Aug 2012 18:19:08 -0400 | From | "J. Bruce Fields" <> | Subject | Re: [PATCH] strings: helper for maximum decimal encoding of an unsigned integer |
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On Tue, Aug 21, 2012 at 11:06:13PM +0100, Al Viro wrote: > On Tue, Aug 21, 2012 at 05:22:27PM -0400, Jim Rees wrote: > > J. Bruce Fields wrote: > > > > From: "J. Bruce Fields" <bfields@redhat.com> > > > > I've seen a couple examples recently where we've gotten this wrong. > > Maybe something like this would help? Is there some better way? > > > > (Approximation due to Jim Rees). > > > > Please add Suggested-by: Jim Rees <rees@umich.edu>. I'm thinking of > > patenting the algorithm. > > Is that a joke? Patenting the fact that log10(256) is 2.408..., which > is about 2.4, which is 24/10? I really hope we are Poe'd... BTW, NAK > the comment - s/36/26/ in there; check it yourself - > $ echo '2^(8*27)' | bc > 105312291668557186697918027683670432318895095400549111254310977536 > which is 66-digit, not 65 as the estimate would be.
Erp, you're right.
Anyway, does something like base10len(type) seem reasonable? Or define macros that enumerate the sizes? (ULONG_STR_MAX or something?)
--b.
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