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 
  31 import java.util.Random;
  32 import static java.lang.Long.*;
  33 
  34 public class BitTwiddle {
  35     private static final int N = 1000; // # of repetitions per test
  36 
  37     public static void main(String args[]) {
  38         Random rnd = new Random();
  39 
  40         if (highestOneBit(0) != 0)
  41             throw new RuntimeException("a");
  42         if (highestOneBit(-1) != MIN_VALUE)
  43             throw new RuntimeException("b");
  44         if (highestOneBit(1) != 1)
  45             throw new RuntimeException("c");
  46 
  47         if (lowestOneBit(0) != 0)
  48             throw new RuntimeException("d");
  49         if (lowestOneBit(-1) != 1)
  50             throw new RuntimeException("e");
  51         if (lowestOneBit(MIN_VALUE) != MIN_VALUE)
  52             throw new RuntimeException("f");
  53 
  54         for (int i = 0; i < N; i++) {
  55             long x = rnd.nextLong();
  56             if (highestOneBit(x) != reverse(lowestOneBit(reverse(x))))
  57                 throw new RuntimeException("g: " + toHexString(x));
  58         }
  59 
  60         if (numberOfLeadingZeros(0) != SIZE)
  61             throw new RuntimeException("h");
  62         if (numberOfLeadingZeros(-1) != 0)
  63             throw new RuntimeException("i");
  64         if (numberOfLeadingZeros(1) != (SIZE - 1))
  65             throw new RuntimeException("j");
  66 
  67         if (numberOfTrailingZeros(0) != SIZE)
  68             throw new RuntimeException("k");
  69         if (numberOfTrailingZeros(1) != 0)
  70             throw new RuntimeException("l");
  71         if (numberOfTrailingZeros(MIN_VALUE) != (SIZE - 1))
  72             throw new RuntimeException("m");
  73 
  74         for (int i = 0; i < N; i++) {
  75             long x = rnd.nextLong();
  76             if (numberOfLeadingZeros(x) != numberOfTrailingZeros(reverse(x)))
  77                 throw new RuntimeException("n: " + toHexString(x));
  78         }
  79 
  80         if (bitCount(0) != 0)
  81                 throw new RuntimeException("o");
  82 
  83         for (int i = 0; i < SIZE; i++) {
  84             long pow2 = 1L << i;
  85             if (bitCount(pow2) != 1)
  86                 throw new RuntimeException("p: " + i);
  87             if (bitCount(pow2 -1) != i)
  88                 throw new RuntimeException("q: " + i);
  89         }
  90 
  91         for (int i = 0; i < N; i++) {
  92             long x = rnd.nextLong();
  93             if (bitCount(x) != bitCount(reverse(x)))
  94                 throw new RuntimeException("r: " + toHexString(x));
  95         }
  96 
  97         for (int i = 0; i < N; i++) {
  98             long x = rnd.nextLong();
  99             int dist = rnd.nextInt();
 100             if (bitCount(x) != bitCount(rotateRight(x, dist)))
 101                 throw new RuntimeException("s: " + toHexString(x) +
 102                                            toHexString(dist));
 103             if (bitCount(x) != bitCount(rotateLeft(x, dist)))
 104                 throw new RuntimeException("t: " + toHexString(x) +
 105                                            toHexString(dist));
 106             if (rotateRight(x, dist) != rotateLeft(x, -dist))
 107                 throw new RuntimeException("u: " + toHexString(x) +
 108                                            toHexString(dist));
 109             if (rotateRight(x, -dist) != rotateLeft(x, dist))
 110                 throw new RuntimeException("v: " + toHexString(x) +
 111                                            toHexString(dist));
 112         }
 113 
 114         if (signum(0) != 0 || signum(1) != 1 || signum(-1) != -1
 115             || signum(MIN_VALUE) != -1 || signum(MAX_VALUE) != 1)
 116             throw new RuntimeException("w");
 117 
 118         for (int i = 0; i < N; i++) {
 119             long x = rnd.nextLong();
 120             int sign = (x < 0 ? -1 : (x == 0 ? 0 : 1));
 121             if (signum(x) != sign)
 122                 throw new RuntimeException("x: " + toHexString(x));
 123         }
 124 
 125         if(reverseBytes(0xaabbccdd11223344L) != 0x44332211ddccbbaaL)
 126             throw new RuntimeException("y");
 127 
 128         for (int i = 0; i < N; i++) {
 129             long x = rnd.nextLong();
 130             if (bitCount(x) != bitCount(reverseBytes(x)))
 131                 throw new RuntimeException("z: " + toHexString(x));
 132         }
 133     }
 134 }