| /* |
| * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test |
| * @bug 4495754 |
| * @summary Basic test for long bit twiddling |
| * @author Josh Bloch |
| */ |
| |
| import java.util.Random; |
| import static java.lang.Long.*; |
| |
| public class BitTwiddle { |
| private static final int N = 1000; // # of repetitions per test |
| |
| public static void main(String args[]) { |
| Random rnd = new Random(); |
| |
| if (highestOneBit(0) != 0) |
| throw new RuntimeException("a"); |
| if (highestOneBit(-1) != MIN_VALUE) |
| throw new RuntimeException("b"); |
| if (highestOneBit(1) != 1) |
| throw new RuntimeException("c"); |
| |
| if (lowestOneBit(0) != 0) |
| throw new RuntimeException("d"); |
| if (lowestOneBit(-1) != 1) |
| throw new RuntimeException("e"); |
| if (lowestOneBit(MIN_VALUE) != MIN_VALUE) |
| throw new RuntimeException("f"); |
| |
| for (int i = 0; i < N; i++) { |
| long x = rnd.nextLong(); |
| if (highestOneBit(x) != reverse(lowestOneBit(reverse(x)))) |
| throw new RuntimeException("g: " + toHexString(x)); |
| } |
| |
| if (numberOfLeadingZeros(0) != SIZE) |
| throw new RuntimeException("h"); |
| if (numberOfLeadingZeros(-1) != 0) |
| throw new RuntimeException("i"); |
| if (numberOfLeadingZeros(1) != (SIZE - 1)) |
| throw new RuntimeException("j"); |
| |
| if (numberOfTrailingZeros(0) != SIZE) |
| throw new RuntimeException("k"); |
| if (numberOfTrailingZeros(1) != 0) |
| throw new RuntimeException("l"); |
| if (numberOfTrailingZeros(MIN_VALUE) != (SIZE - 1)) |
| throw new RuntimeException("m"); |
| |
| for (int i = 0; i < N; i++) { |
| long x = rnd.nextLong(); |
| if (numberOfLeadingZeros(x) != numberOfTrailingZeros(reverse(x))) |
| throw new RuntimeException("n: " + toHexString(x)); |
| } |
| |
| if (bitCount(0) != 0) |
| throw new RuntimeException("o"); |
| |
| for (int i = 0; i < SIZE; i++) { |
| long pow2 = 1L << i; |
| if (bitCount(pow2) != 1) |
| throw new RuntimeException("p: " + i); |
| if (bitCount(pow2 -1) != i) |
| throw new RuntimeException("q: " + i); |
| } |
| |
| for (int i = 0; i < N; i++) { |
| long x = rnd.nextLong(); |
| if (bitCount(x) != bitCount(reverse(x))) |
| throw new RuntimeException("r: " + toHexString(x)); |
| } |
| |
| for (int i = 0; i < N; i++) { |
| long x = rnd.nextLong(); |
| int dist = rnd.nextInt(); |
| if (bitCount(x) != bitCount(rotateRight(x, dist))) |
| throw new RuntimeException("s: " + toHexString(x) + |
| toHexString(dist)); |
| if (bitCount(x) != bitCount(rotateLeft(x, dist))) |
| throw new RuntimeException("t: " + toHexString(x) + |
| toHexString(dist)); |
| if (rotateRight(x, dist) != rotateLeft(x, -dist)) |
| throw new RuntimeException("u: " + toHexString(x) + |
| toHexString(dist)); |
| if (rotateRight(x, -dist) != rotateLeft(x, dist)) |
| throw new RuntimeException("v: " + toHexString(x) + |
| toHexString(dist)); |
| } |
| |
| if (signum(0) != 0 || signum(1) != 1 || signum(-1) != -1 |
| || signum(MIN_VALUE) != -1 || signum(MAX_VALUE) != 1) |
| throw new RuntimeException("w"); |
| |
| for (int i = 0; i < N; i++) { |
| long x = rnd.nextLong(); |
| int sign = (x < 0 ? -1 : (x == 0 ? 0 : 1)); |
| if (signum(x) != sign) |
| throw new RuntimeException("x: " + toHexString(x)); |
| } |
| |
| if(reverseBytes(0xaabbccdd11223344L) != 0x44332211ddccbbaaL) |
| throw new RuntimeException("y"); |
| |
| for (int i = 0; i < N; i++) { |
| long x = rnd.nextLong(); |
| if (bitCount(x) != bitCount(reverseBytes(x))) |
| throw new RuntimeException("z: " + toHexString(x)); |
| } |
| } |
| } |