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Java example source code file (Unsigned.java)

This example Java source code file (Unsigned.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bad, biginteger, correct, math, max_unsigned_int, runtimeexception, should, string, two, unexpected, unsigned, value

The Unsigned.java Java example source code

/*
 * Copyright (c) 2009, 2012, 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 4504839 4215269 6322074
 * @summary Basic tests for unsigned operations
 * @author Joseph D. Darcy
 */

import java.math.*;

public class Unsigned {
    public static void main(String... args) {
        int errors = 0;

        errors += testRoundtrip();
        errors += testByteToUnsignedLong();
        errors += testShortToUnsignedLong();
        errors += testUnsignedCompare();
        errors += testToStringUnsigned();
        errors += testParseUnsignedLong();
        errors += testDivideAndRemainder();

        if (errors > 0) {
            throw new RuntimeException(errors + " errors found in unsigned operations.");
        }
    }

    private static final BigInteger TWO = BigInteger.valueOf(2L);

    private static int testRoundtrip() {
        int errors = 0;

        long[] data = {-1L, 0L, 1L};

        for(long datum : data) {
            if (Long.parseUnsignedLong(Long.toBinaryString(datum), 2) != datum) {
                errors++;
                System.err.println("Bad binary roundtrip conversion of " + datum);
            }

            if (Long.parseUnsignedLong(Long.toOctalString(datum), 8) != datum) {
                errors++;
                System.err.println("Bad octal roundtrip conversion of " + datum);
            }

            if (Long.parseUnsignedLong(Long.toHexString(datum), 16) != datum) {
                errors++;
                System.err.println("Bad hex roundtrip conversion of " + datum);
            }
        }
        return errors;
    }

    private static int testByteToUnsignedLong() {
        int errors = 0;

        for(int i = Byte.MIN_VALUE; i <= Byte.MAX_VALUE; i++) {
            byte datum = (byte) i;
            long ui = Byte.toUnsignedLong(datum);

            if ( (ui & (~0xffL)) != 0L ||
                 ((byte)ui != datum )) {
                errors++;
                System.err.printf("Bad conversion of byte %d to unsigned long %d%n",
                                  datum, ui);
            }
        }
        return errors;
    }

    private static int testShortToUnsignedLong() {
        int errors = 0;

        for(int i = Short.MIN_VALUE; i <= Short.MAX_VALUE; i++) {
            short datum = (short) i;
            long ui = Short.toUnsignedLong(datum);

            if ( (ui & (~0xffffL)) != 0L ||
                 ((short)ui != datum )) {
                errors++;
                System.err.printf("Bad conversion of short %d to unsigned long %d%n",
                                  datum, ui);
            }
        }
        return errors;
    }
    private static int testUnsignedCompare() {
        int errors = 0;

        long[] data = {
            0L,
            1L,
            2L,
            3L,
            0x00000000_80000000L,
            0x00000000_FFFFFFFFL,
            0x00000001_00000000L,
            0x80000000_00000000L,
            0x80000000_00000001L,
            0x80000000_00000002L,
            0x80000000_00000003L,
            0x80000000_80000000L,
            0xFFFFFFFF_FFFFFFFEL,
            0xFFFFFFFF_FFFFFFFFL,
        };

        for(long i : data) {
            for(long j : data) {
                long libraryResult    = Long.compareUnsigned(i, j);
                long libraryResultRev = Long.compareUnsigned(j, i);
                long localResult      = compUnsigned(i, j);

                if (i == j) {
                    if (libraryResult != 0) {
                        errors++;
                        System.err.printf("Value 0x%x did not compare as " +
                                          "an unsigned equal to itself; got %d%n",
                                          i, libraryResult);
                    }
                }

                   if (Long.signum(libraryResult) != Long.signum(localResult)) {
                       errors++;
                       System.err.printf("Unsigned compare of 0x%x to 0x%x%n:" +
                                         "\texpected sign of %d, got %d%n",
                                         i, j, localResult, libraryResult);
                   }

                if (Long.signum(libraryResult) !=
                    -Long.signum(libraryResultRev)) {
                    errors++;
                    System.err.printf("signum(compareUnsigned(x, y)) != -signum(compareUnsigned(y,x))" +
                                      " for \t0x%x and 0x%x, computed %d and %d%n",
                                      i, j, libraryResult, libraryResultRev);
                }
            }
        }

        return errors;
    }

    private static int compUnsigned(long x, long y) {
        BigInteger big_x = toUnsignedBigInt(x);
        BigInteger big_y = toUnsignedBigInt(y);

        return big_x.compareTo(big_y);
    }

    private static BigInteger toUnsignedBigInt(long x) {
        if (x >= 0)
            return BigInteger.valueOf(x);
        else {
            int upper = (int)(((long)x) >> 32);
            int lower = (int) x;

            BigInteger bi = // (upper << 32) + lower
                (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
                add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));

            // System.out.printf("%n\t%d%n\t%s%n", x, bi.toString());
            return bi;
        }
    }

    private static int testToStringUnsigned() {
        int errors = 0;

        long[] data = {
            0L,
            1L,
            2L,
            3L,
            99999L,
            100000L,
            999999L,
            100000L,
            999999999L,
            1000000000L,
            0x1234_5678L,
            0x8000_0000L,
            0x8000_0001L,
            0x8000_0002L,
            0x8000_0003L,
            0x8765_4321L,
            0xFFFF_FFFEL,
            0xFFFF_FFFFL,

            // Long-range values
              999_999_999_999L,
            1_000_000_000_000L,

              999_999_999_999_999_999L,
            1_000_000_000_000_000_000L,

            0xFFFF_FFFF_FFFF_FFFEL,
            0xFFFF_FFFF_FFFF_FFFFL,
        };

        for(int radix = Character.MIN_RADIX; radix <= Character.MAX_RADIX; radix++) {
            for(long datum : data) {
                String result1 = Long.toUnsignedString(datum, radix);
                String result2 = toUnsignedBigInt(datum).toString(radix);

                if (!result1.equals(result2)) {
                    errors++;
                    System.err.printf("Unexpected string difference converting 0x%x:" +
                                      "\t%s %s%n",
                                      datum, result1, result2);
                }

                if (radix == 10) {
                    String result3 = Long.toUnsignedString(datum);
                    if (!result2.equals(result3)) {
                        errors++;
                        System.err.printf("Unexpected string difference converting 0x%x:" +
                                          "\t%s %s%n",
                                          datum, result3, result2);
                    }
                }

                long parseResult = Long.parseUnsignedLong(result1, radix);

                if (parseResult != datum) {
                    errors++;
                        System.err.printf("Bad roundtrip conversion of %d in base %d" +
                                          "\tconverting back ''%s'' resulted in %d%n",
                                          datum, radix, result1,  parseResult);
                }
            }
        }

        return errors;
    }

    private static int testParseUnsignedLong() {
        int errors = 0;
        long maxUnsignedInt = Integer.toUnsignedLong(0xffff_ffff);

        // Values include those between signed Long.MAX_VALUE and
        // unsignted Long MAX_VALUE.
        BigInteger[] inRange = {
            BigInteger.valueOf(0L),
            BigInteger.valueOf(1L),
            BigInteger.valueOf(10L),
            BigInteger.valueOf(2147483646L),   // Integer.MAX_VALUE - 1
            BigInteger.valueOf(2147483647L),   // Integer.MAX_VALUE
            BigInteger.valueOf(2147483648L),   // Integer.MAX_VALUE + 1

            BigInteger.valueOf(maxUnsignedInt - 1L),
            BigInteger.valueOf(maxUnsignedInt),

            BigInteger.valueOf(Long.MAX_VALUE - 1L),
            BigInteger.valueOf(Long.MAX_VALUE),
            BigInteger.valueOf(Long.MAX_VALUE).add(BigInteger.ONE),

            TWO.pow(64).subtract(BigInteger.ONE)
        };

        for(BigInteger value : inRange) {
            for(int radix = Character.MIN_RADIX; radix <= Character.MAX_RADIX; radix++) {
                String bigString = value.toString(radix);
                long longResult = Long.parseUnsignedLong(bigString, radix);

                if (!toUnsignedBigInt(longResult).equals(value)) {
                    errors++;
                    System.err.printf("Bad roundtrip conversion of %d in base %d" +
                                      "\tconverting back ''%s'' resulted in %d%n",
                                      value, radix, bigString,  longResult);
                }
            }
        }

        String[] outOfRange = {
            null,
            "",
            "-1",
            TWO.pow(64).toString(),
        };

        for(String s : outOfRange) {
            try {
                long result = Long.parseUnsignedLong(s);
                errors++; // Should not reach here
                System.err.printf("Unexpected got %d from an unsigned conversion of %s",
                                  result, s);
            } catch(NumberFormatException nfe) {
                ; // Correct result
            }
        }

        return errors;
    }

    private static int testDivideAndRemainder() {
        int errors = 0;
        long MAX_UNSIGNED_INT = Integer.toUnsignedLong(0xffff_ffff);

        BigInteger[] inRange = {
            BigInteger.valueOf(0L),
            BigInteger.valueOf(1L),
            BigInteger.valueOf(10L),
            BigInteger.valueOf(2147483646L),   // Integer.MAX_VALUE - 1
            BigInteger.valueOf(2147483647L),   // Integer.MAX_VALUE
            BigInteger.valueOf(2147483648L),   // Integer.MAX_VALUE + 1

            BigInteger.valueOf(MAX_UNSIGNED_INT - 1L),
            BigInteger.valueOf(MAX_UNSIGNED_INT),

            BigInteger.valueOf(Long.MAX_VALUE - 1L),
            BigInteger.valueOf(Long.MAX_VALUE),
            BigInteger.valueOf(Long.MAX_VALUE).add(BigInteger.ONE),

            TWO.pow(64).subtract(BigInteger.ONE)
        };

        for(BigInteger dividend : inRange) {
            for(BigInteger divisor : inRange) {
                long quotient;
                BigInteger longQuotient;

                long remainder;
                BigInteger longRemainder;

                if (divisor.equals(BigInteger.ZERO)) {
                    try {
                        quotient = Long.divideUnsigned(dividend.longValue(), divisor.longValue());
                        errors++;
                    } catch(ArithmeticException ea) {
                        ; // Expected
                    }

                    try {
                        remainder = Long.remainderUnsigned(dividend.longValue(), divisor.longValue());
                        errors++;
                    } catch(ArithmeticException ea) {
                        ; // Expected
                    }
                } else {
                    quotient = Long.divideUnsigned(dividend.longValue(), divisor.longValue());
                    longQuotient = dividend.divide(divisor);

                    if (quotient != longQuotient.longValue()) {
                        errors++;
                        System.err.printf("Unexpected unsigned divide result %s on %s/%s%n",
                                          Long.toUnsignedString(quotient),
                                          Long.toUnsignedString(dividend.longValue()),
                                          Long.toUnsignedString(divisor.longValue()));
                    }

                    remainder = Long.remainderUnsigned(dividend.longValue(), divisor.longValue());
                    longRemainder = dividend.remainder(divisor);

                    if (remainder != longRemainder.longValue()) {
                        errors++;
                        System.err.printf("Unexpected unsigned remainder result %s on %s%%%s%n",
                                          Long.toUnsignedString(remainder),
                                          Long.toUnsignedString(dividend.longValue()),
                                          Long.toUnsignedString(divisor.longValue()));
                    }
                }
            }
        }

        return errors;
    }
}

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