On 26.06.2013, at 7:31, Dmitry Nadezhin <dmitry.nadez...@gmail.com> wrote:
> We have two versions after private discussion with Aleksey.
>
> BigInteger getRadixConversionCache(int radix, int exponent) {
> BigInteger[][] pc = powerCache; // volatile read
> BigInteger[] cacheLine = pc[radix];
> if (exponent < cacheLine.length)
> return cacheLine[exponent];
>
> int oldSize = cacheLine.length;
> cacheLine = Arrays.copyOf(cacheLine, exponent + 1);
> for (int i = oldSize; i < exponent + 1; i++)
> cacheLine[i] = cacheLine[i - 1].square();
>
> pc = Arrays.copyOf(powerCache);
> pc[radix] = cacheLine;
> powerCache = pc; // volatile write, publish
> return cacheLine[exponent];
> }
Thanks, I like this version a lot better. We could check for the existing
cacheLine.length right before installing the new one, so the opportunity to
overwrite larger cacheLine would be minimal, but I do think the probability of
unlucky timing is very low, and the argument is moot :) Let's keep it simple.
-Aleksey.
