1 /* 2 * Copyright 2003 Sun Microsystems, Inc. All Rights Reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 */ 23 24 /* 25 * @test 26 * @bug 4495754 27 * @summary Basic test for long bit twiddling 28 * @author Josh Bloch 29 * 30 * @compile -source 1.5 BitTwiddle.java 31 * @run main BitTwiddle 32 */ 33 34 import java.util.Random; 35 import static java.lang.Long.*; 36 37 public class BitTwiddle { 38 private static final int N = 1000; // # of repetitions per test 39 40 public static void main(String args[]) { 41 Random rnd = new Random(); 42 43 if (highestOneBit(0) != 0) 44 throw new RuntimeException("a"); 45 if (highestOneBit(-1) != MIN_VALUE) 46 throw new RuntimeException("b"); 47 if (highestOneBit(1) != 1) 48 throw new RuntimeException("c"); 49 50 if (lowestOneBit(0) != 0) 51 throw new RuntimeException("d"); 52 if (lowestOneBit(-1) != 1) 53 throw new RuntimeException("e"); 54 if (lowestOneBit(MIN_VALUE) != MIN_VALUE) 55 throw new RuntimeException("f"); 56 57 for (int i = 0; i < N; i++) { 58 long x = rnd.nextLong(); 59 if (highestOneBit(x) != reverse(lowestOneBit(reverse(x)))) 60 throw new RuntimeException("g: " + toHexString(x)); 61 } 62 63 if (numberOfLeadingZeros(0) != SIZE) 64 throw new RuntimeException("h"); 65 if (numberOfLeadingZeros(-1) != 0) 66 throw new RuntimeException("i"); 67 if (numberOfLeadingZeros(1) != (SIZE - 1)) 68 throw new RuntimeException("j"); 69 70 if (numberOfTrailingZeros(0) != SIZE) 71 throw new RuntimeException("k"); 72 if (numberOfTrailingZeros(1) != 0) 73 throw new RuntimeException("l"); 74 if (numberOfTrailingZeros(MIN_VALUE) != (SIZE - 1)) 75 throw new RuntimeException("m"); 76 77 for (int i = 0; i < N; i++) { 78 long x = rnd.nextLong(); 79 if (numberOfLeadingZeros(x) != numberOfTrailingZeros(reverse(x))) 80 throw new RuntimeException("n: " + toHexString(x)); 81 } 82 83 if (bitCount(0) != 0) 84 throw new RuntimeException("o"); 85 86 for (int i = 0; i < SIZE; i++) { 87 long pow2 = 1L << i; 88 if (bitCount(pow2) != 1) 89 throw new RuntimeException("p: " + i); 90 if (bitCount(pow2 -1) != i) 91 throw new RuntimeException("q: " + i); 92 } 93 94 for (int i = 0; i < N; i++) { 95 long x = rnd.nextLong(); 96 if (bitCount(x) != bitCount(reverse(x))) 97 throw new RuntimeException("r: " + toHexString(x)); 98 } 99 100 for (int i = 0; i < N; i++) { 101 long x = rnd.nextLong(); 102 int dist = rnd.nextInt(); 103 if (bitCount(x) != bitCount(rotateRight(x, dist))) 104 throw new RuntimeException("s: " + toHexString(x) + 105 toHexString(dist)); 106 if (bitCount(x) != bitCount(rotateLeft(x, dist))) 107 throw new RuntimeException("t: " + toHexString(x) + 108 toHexString(dist)); 109 if (rotateRight(x, dist) != rotateLeft(x, -dist)) 110 throw new RuntimeException("u: " + toHexString(x) + 111 toHexString(dist)); 112 if (rotateRight(x, -dist) != rotateLeft(x, dist)) 113 throw new RuntimeException("v: " + toHexString(x) + 114 toHexString(dist)); 115 } 116 117 if (signum(0) != 0 || signum(1) != 1 || signum(-1) != -1 118 || signum(MIN_VALUE) != -1 || signum(MAX_VALUE) != 1) 119 throw new RuntimeException("w"); 120 121 for (int i = 0; i < N; i++) { 122 long x = rnd.nextLong(); 123 int sign = (x < 0 ? -1 : (x == 0 ? 0 : 1)); 124 if (signum(x) != sign) 125 throw new RuntimeException("x: " + toHexString(x)); 126 } 127 128 if(reverseBytes(0xaabbccdd11223344L) != 0x44332211ddccbbaaL) 129 throw new RuntimeException("y"); 130 131 for (int i = 0; i < N; i++) { 132 long x = rnd.nextLong(); 133 if (bitCount(x) != bitCount(reverseBytes(x))) 134 throw new RuntimeException("z: " + toHexString(x)); 135 } 136 } 137 }