[HarfBuzz] TrueType spec bsearch algorithm?

[Behdad Esfahbod]

Hi Jonathan,

So, many places in the TrueType spec, there are these searchRange,
entrySelector, and rangeShift values that seem to be there to facilitate a
fast binary search algorithm.  I cannot quite get the intended algorithm
though (not that I want to implement it, just want to learn).  I know you've
used them Firefox, can you please explain or point me to the code?

Thanks,
behdad