On Mon, Apr 26, 2010 at 6:10 PM, Peter Samuelson <pe...@p12n.org> wrote:
> > [Philip Martin] > > We have svn_ctype_isalpha which is a macro that does a table lookup. > > We don't currently have svn_ctype_isxdigit but it could be added. > > > > > I'd rather see the whole thing become a single table lookup. Untested > > > patch appended. > > > > Is this a bottleneck? I think using the svn_ctype.h macros should be > > sufficient. > > I don't know if it's a bottleneck. But given that what we actually > want to know if 'what is the value of this hex digit' - using isxdigit, > then isalpha as a conditional, then ASCII arithmetic is awfully > roundabout compared to just a single table lookup. > > I mean, the whole point of those ctype functions is to avoid ASCII > arithmetic. So, while I don't claim my patch will be noticeably faster > (it will be faster but probably not noticeably so), I do claim it's > more elegant. I would agree. I saw the commit of Stefan's patch, and independently thought about using a lookup table (though I prefer Peter's implementation). I don't have any hard performance numbers, but I gotta believe the lookup table is simpler, as well as more performant. -Hyrum
