Guidance about binary / data files for JTREG tests

Florian Weimer fweimer at
Mon Apr 28 18:52:11 UTC 2014

On 04/28/2014 07:53 PM, Brian Burkhalter wrote:

> Meanwhile I suppose that I could convert my test file and use the sun.misc.UU{En,De}coder classes to handle it in the test.

Uh-oh, we have java.util.Base64 these days.

But in this case, it's probably simpler to use this code snippet instead 
of adding 235 KiB of incompressible binary data to the source code.

     private static boolean[] primes(int n) {
	boolean[] primes = new boolean[n + 1];
	Arrays.fill(primes, true);
	primes[0] = false;
	primes[1] = false;
	for (int p = 2; p * p < n; ) {
	    for (int i = 2 * p; i < primes.length; i += p)
		primes[i] = false;
	    while (!primes[p]);
	return primes;

(I hope it's correct, but you get the idea…)

Anyway, for the first 100K primes, it runs in roughly 400 ms on my 
machine, including JVM startup and teardown.  That should be completely 
negligible compared to actually testing all the numbers for primality 
using a any non-sieve algorithm.

Florian Weimer / Red Hat Product Security Team

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