On Mon, Oct 7, 2013 at 1:28 PM, Jonathan Wakely <jwakely....@gmail.com> wrote: > std::memset() on about 125 bytes is not a big deal, I doubt it's > significantly more expensive than the calculations to find the right > bits and do the necessary masking for three elements. > std::vector<bool> is a strange beast, remember.
Probably there could be bitwise operation? I've test the 3 trues out of 1000 elements here : https://gist.github.com/innocentim/6874889 In my machine, choosing "v.assign(v.size(), false);" cost 1.768s and choosing the other cost 1.088s. When we push 7 elements, they cost almost same time. When push more than that, v.assign() shall win. I do this because I need to use _M_clear() in this patch :) Anyway let's use v.assign(). Thanks! -- Tim Shen
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