CompareToTests.java example

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openjdk8-jdk-master
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 * 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).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug 6473768
 * @summary Tests of BigInteger.compareTo
 * @author Joseph D. Darcy
 */
import java.math.*;
import static java.math.BigInteger.*;

public class CompareToTests {
    private static int compareToTests() {
        int failures = 0;

        final BigInteger MINUS_ONE = BigInteger.ONE.negate();
        final BigInteger TWO_POW_126 = ONE.shiftLeft(126);
        final BigInteger TWO_POW_127 = ONE.shiftLeft(127);
        final BigInteger TWO_POW_128 = ONE.shiftLeft(128);

        // First operand, second operand, expected compareTo result
        BigInteger [][] testCases = {
            // Basics
            {valueOf(0),        valueOf(0),     ZERO},
            {valueOf(0),        valueOf(1),     MINUS_ONE},
            {valueOf(1),        valueOf(2),     MINUS_ONE},
            {valueOf(2),        valueOf(1),     ONE},
            {valueOf(10),       valueOf(10),    ZERO},

            // Various relative lengths of internal mag array.
            {TWO_POW_127,                 TWO_POW_127,                 ZERO},
            {TWO_POW_127.negate(),        TWO_POW_127,                 MINUS_ONE},

            {TWO_POW_128.or(TWO_POW_126), TWO_POW_128,                 ONE},
            {TWO_POW_128.or(TWO_POW_126), TWO_POW_128.negate(),        ONE},

            {TWO_POW_128,                 TWO_POW_128.or(TWO_POW_126), MINUS_ONE},
            {TWO_POW_128.negate(),        TWO_POW_128.or(TWO_POW_126), MINUS_ONE},

            {TWO_POW_127,                 TWO_POW_128,                 MINUS_ONE},
            {TWO_POW_127.negate(),        TWO_POW_128,                 MINUS_ONE},

            {TWO_POW_128,                 TWO_POW_127,                 ONE},
            {TWO_POW_128.negate(),        TWO_POW_127,                 MINUS_ONE},

            // Long boundary and near boundary values
            {valueOf(Long.MAX_VALUE),            valueOf(Long.MAX_VALUE), ZERO},
            {valueOf(Long.MAX_VALUE).negate(),   valueOf(Long.MAX_VALUE), MINUS_ONE},

            {valueOf(Long.MAX_VALUE-1),          valueOf(Long.MAX_VALUE), MINUS_ONE},
            {valueOf(Long.MAX_VALUE-1).negate(), valueOf(Long.MAX_VALUE), MINUS_ONE},

            {valueOf(Long.MIN_VALUE),            valueOf(Long.MAX_VALUE), MINUS_ONE},
            {valueOf(Long.MIN_VALUE).negate(),   valueOf(Long.MAX_VALUE), ONE},

            {valueOf(Long.MIN_VALUE+1),          valueOf(Long.MAX_VALUE), MINUS_ONE},
            {valueOf(Long.MIN_VALUE+1).negate(), valueOf(Long.MAX_VALUE), ZERO},

            {valueOf(Long.MAX_VALUE),            valueOf(Long.MIN_VALUE), ONE},
            {valueOf(Long.MAX_VALUE).negate(),   valueOf(Long.MIN_VALUE), ONE},

            {valueOf(Long.MAX_VALUE-1),          valueOf(Long.MIN_VALUE), ONE},
            {valueOf(Long.MAX_VALUE-1).negate(), valueOf(Long.MIN_VALUE), ONE},

            {valueOf(Long.MIN_VALUE),            valueOf(Long.MIN_VALUE), ZERO},
            {valueOf(Long.MIN_VALUE).negate(),   valueOf(Long.MIN_VALUE), ONE},

            {valueOf(Long.MIN_VALUE+1),          valueOf(Long.MIN_VALUE), ONE},
            {valueOf(Long.MIN_VALUE+1).negate(), valueOf(Long.MIN_VALUE), ONE},
        };

        for (BigInteger[] testCase : testCases) {
            BigInteger a = testCase[0];
            BigInteger a_negate = a.negate();
            BigInteger b = testCase[1];
            BigInteger b_negate = b.negate();
            int expected = testCase[2].intValue();

            failures += compareToTest(a,        b,         expected);
            failures += compareToTest(a_negate, b_negate, -expected);
        }


        return failures;
    }

    private static int compareToTest(BigInteger a, BigInteger b, int expected) {
        int result = a.compareTo(b);
        int failed = (result==expected) ? 0 : 1;
        if (failed == 1) {
            System.err.println("(" + a + ").compareTo(" + b + ") => " + result +
                               "\n\tExpected " + expected);
        }
        return failed;
    }

    public static void main(String argv[]) {
        int failures = 0;

        failures += compareToTests();

        if (failures > 0) {
            throw new RuntimeException("Incurred " + failures +
                                       " failures while testing exact compareTo.");
        }
    }
}