1 /*
2 * License : The MIT License
3 * Copyright(c) 2022 Olyutorskii
4 */
5
6 package io.github.olyutorskii.aletojio.idling;
7
8 /**
9 * Monitor pop-count of random number sequence.
10 *
11 * <ul>
12 * <li>pop-count of 0x00000000 is 0
13 * <li>pop-count of 0xa5a5a5a5 is 16
14 * <li>pop-count of 0xffffffff is 32
15 * </ul>
16 *
17 * <p>Pop-count is another name for Hamming-weight.
18 *
19 * @see <a href="https://en.wikipedia.org/wiki/Hamming_weight">Hamming weight(Wikipedia)</a>
20 */
21 public class PopCntMonitor extends AbstractRndMonitor {
22
23 private final int popCt;
24
25
26 /**
27 * Constructor.
28 *
29 * @param pop pop counts (must be 0<= and <= 32)
30 * @throws IllegalArgumentException pop counts too small or large
31 */
32 public PopCntMonitor(int pop) throws IllegalArgumentException {
33 super();
34
35 if (pop < 0 || Integer.SIZE < pop) {
36 throw new IllegalArgumentException();
37 }
38
39 this.popCt = pop;
40
41 return;
42 }
43
44
45 /**
46 * {@inheritDoc}
47 */
48 @Override
49 protected void resetImpl() {
50 assert true;
51 }
52
53 /**
54 * {@inheritDoc}
55 *
56 * @param iVal {@inheritDoc}
57 * @return {@inheritDoc}
58 */
59 @Override
60 protected boolean probeImpl(int iVal) {
61 boolean result =
62 Integer.bitCount(iVal) == this.popCt;
63 return result;
64 }
65
66 }