30e8183ee8
Add ability to initial the random number generator from the system property "seed" and print to STDOUT the seed value actually used. Reviewed-by: darcy
139 lines
5.1 KiB
Java
139 lines
5.1 KiB
Java
/*
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* Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test
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* @library /lib/testlibrary/
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* @build jdk.testlibrary.*
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* @run main BitTwiddle
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* @bug 4495754 8078672
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* @summary Basic test for int bit twiddling (use -Dseed=X to set PRNG seed)
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* @author Josh Bloch
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* @key randomness
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*/
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import java.util.Random;
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import static java.lang.Integer.*;
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public class BitTwiddle {
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private static final int N = 1000; // # of repetitions per test
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public static void main(String args[]) {
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Random rnd = RandomFactory.getRandom();
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if (highestOneBit(0) != 0)
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throw new RuntimeException("a");
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if (highestOneBit(-1) != MIN_VALUE)
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throw new RuntimeException("b");
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if (highestOneBit(1) != 1)
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throw new RuntimeException("c");
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if (lowestOneBit(0) != 0)
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throw new RuntimeException("d");
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if (lowestOneBit(-1) != 1)
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throw new RuntimeException("e");
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if (lowestOneBit(MIN_VALUE) != MIN_VALUE)
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throw new RuntimeException("f");
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for (int i = 0; i < N; i++) {
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int x = rnd.nextInt();
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if (highestOneBit(x) != reverse(lowestOneBit(reverse(x))))
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throw new RuntimeException("g: " + toHexString(x));
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}
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if (numberOfLeadingZeros(0) != SIZE)
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throw new RuntimeException("h");
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if (numberOfLeadingZeros(-1) != 0)
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throw new RuntimeException("i");
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if (numberOfLeadingZeros(1) != (SIZE - 1))
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throw new RuntimeException("j");
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if (numberOfTrailingZeros(0) != SIZE)
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throw new RuntimeException("k");
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if (numberOfTrailingZeros(1) != 0)
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throw new RuntimeException("l");
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if (numberOfTrailingZeros(MIN_VALUE) != (SIZE - 1))
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throw new RuntimeException("m");
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for (int i = 0; i < N; i++) {
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int x = rnd.nextInt();
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if (numberOfLeadingZeros(x) != numberOfTrailingZeros(reverse(x)))
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throw new RuntimeException("n: " + toHexString(x));
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}
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if (bitCount(0) != 0)
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throw new RuntimeException("o");
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for (int i = 0; i < SIZE; i++) {
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int pow2 = 1 << i;
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if (bitCount(pow2) != 1)
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throw new RuntimeException("p: " + i);
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if (bitCount(pow2 -1) != i)
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throw new RuntimeException("q: " + i);
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}
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for (int i = 0; i < N; i++) {
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int x = rnd.nextInt();
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if (bitCount(x) != bitCount(reverse(x)))
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throw new RuntimeException("r: " + toHexString(x));
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}
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for (int i = 0; i < N; i++) {
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int x = rnd.nextInt();
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int dist = rnd.nextInt();
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if (bitCount(x) != bitCount(rotateRight(x, dist)))
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throw new RuntimeException("s: " + toHexString(x) +
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toHexString(dist));
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if (bitCount(x) != bitCount(rotateLeft(x, dist)))
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throw new RuntimeException("t: " + toHexString(x) +
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toHexString(dist));
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if (rotateRight(x, dist) != rotateLeft(x, -dist))
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throw new RuntimeException("u: " + toHexString(x) +
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toHexString(dist));
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if (rotateRight(x, -dist) != rotateLeft(x, dist))
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throw new RuntimeException("v: " + toHexString(x) +
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toHexString(dist));
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}
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if (signum(0) != 0 || signum(1) != 1 || signum(-1) != -1
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|| signum(MIN_VALUE) != -1 || signum(MAX_VALUE) != 1)
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throw new RuntimeException("w");
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for (int i = 0; i < N; i++) {
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int x = rnd.nextInt();
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int sign = (x < 0 ? -1 : (x == 0 ? 0 : 1));
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if (signum(x) != sign)
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throw new RuntimeException("x: " + toHexString(x));
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}
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if(reverseBytes(0xaabbccdd) != 0xddccbbaa)
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throw new RuntimeException("y");
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for (int i = 0; i < N; i++) {
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int x = rnd.nextInt();
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if (bitCount(x) != bitCount(reverseBytes(x)))
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throw new RuntimeException("z: " + toHexString(x));
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}
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}
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}
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