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 }