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 * Copyright (c) 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

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 */

import java.math.BigInteger;

/**

 * @test Test for Math.*Exact integer and long methods.

 * @bug 6708398

 * @summary Basic tests for Math exact arithmetic operations.

 *

 * @author Roger Riggs

 */

public class ExactArithTests {

    /**

     * The count of test errors.

     */

    private static int errors = 0;

    /**

     * @param args the command line arguments

     */

    public static void main(String[] args) {

        testIntegerExact();

        testLongExact();

        if (errors > 0) {

            throw new RuntimeException(errors + " errors found in ExactArithTests.");

        }

    }

    static void fail(String message) {

        errors++;

        System.err.println(message);

    }

    /**

     * Test Math.addExact, multiplyExact, subtractExact, toIntValue methods

     * with {@code int} arguments.

     */

    static void testIntegerExact() {

        testIntegerExact(0, 0);

        testIntegerExact(1, 1);

        testIntegerExact(1, -1);

        testIntegerExact(-1, 1);

        testIntegerExact(1000, 2000);

        testIntegerExact(Integer.MIN_VALUE, Integer.MIN_VALUE);

        testIntegerExact(Integer.MAX_VALUE, Integer.MAX_VALUE);

        testIntegerExact(Integer.MIN_VALUE, 1);

        testIntegerExact(Integer.MAX_VALUE, 1);

        testIntegerExact(Integer.MIN_VALUE, 2);

        testIntegerExact(Integer.MAX_VALUE, 2);

        testIntegerExact(Integer.MIN_VALUE, -1);

        testIntegerExact(Integer.MAX_VALUE, -1);

        testIntegerExact(Integer.MIN_VALUE, -2);

        testIntegerExact(Integer.MAX_VALUE, -2);

    }

    /**

     * Test exact arithmetic by comparing with the same operations using long

     * and checking that the result is the same as the integer truncation.

     * Errors are reported with {@link fail}.

     *

     * @param x first parameter

     * @param y second parameter

     */

    static void testIntegerExact(int x, int y) {

        try {

            // Test addExact

            int sum = Math.addExact(x, y);

            long sum2 = (long) x + (long) y;

            if ((int) sum2 != sum2) {

                fail("FAIL: int Math.addExact(" + x + " + " + y + ") = " + sum + "; expected Arithmetic exception");

            } else if (sum != sum2) {

                fail("FAIL: long Math.addExact(" + x + " + " + y + ") = " + sum + "; expected: " + sum2);

            }

        } catch (ArithmeticException ex) {

            long sum2 = (long) x + (long) y;

            if ((int) sum2 == sum2) {

                fail("FAIL: int Math.addExact(" + x + " + " + y + ")" + "; Unexpected exception: " + ex);

            }

        }

        try {

            // Test subtractExact

            int diff = Math.subtractExact(x, y);

            long diff2 = (long) x - (long) y;

            if ((int) diff2 != diff2) {

                fail("FAIL: int Math.subtractExact(" + x + " - " + y + ") = " + diff + "; expected: " + diff2);

            }

        } catch (ArithmeticException ex) {

            long diff2 = (long) x - (long) y;

            if ((int) diff2 == diff2) {

                fail("FAIL: int Math.subtractExact(" + x + " - " + y + ")" + "; Unexpected exception: " + ex);

            }

        }

        try {

            // Test multiplyExact

            int product = Math.multiplyExact(x, y);

            long m2 = (long) x * (long) y;

            if ((int) m2 != m2) {

                fail("FAIL: int Math.multiplyExact(" + x + " * " + y + ") = " + product + "; expected: " + m2);

            }

        } catch (ArithmeticException ex) {

            long m2 = (long) x * (long) y;

            if ((int) m2 == m2) {

                fail("FAIL: int Math.multiplyExact(" + x + " * " + y + ")" + "; Unexpected exception: " + ex);

            }

        }

    }

    /**

     * Test Math.addExact, multiplyExact, subtractExact, toIntExact methods

     * with {@code long} arguments.

     */

    static void testLongExact() {

        testLongExactTwice(0, 0);

        testLongExactTwice(1, 1);

        testLongExactTwice(1, -1);

        testLongExactTwice(1000, 2000);

        testLongExactTwice(Long.MIN_VALUE, Long.MIN_VALUE);

        testLongExactTwice(Long.MAX_VALUE, Long.MAX_VALUE);

        testLongExactTwice(Long.MIN_VALUE, 1);

        testLongExactTwice(Long.MAX_VALUE, 1);

        testLongExactTwice(Long.MIN_VALUE, 2);

        testLongExactTwice(Long.MAX_VALUE, 2);

        testLongExactTwice(Long.MIN_VALUE, -1);

        testLongExactTwice(Long.MAX_VALUE, -1);

        testLongExactTwice(Long.MIN_VALUE, -2);

        testLongExactTwice(Long.MAX_VALUE, -2);

        testLongExactTwice(Long.MIN_VALUE/2, 2);

        testLongExactTwice(Long.MAX_VALUE, 2);

        testLongExactTwice(Integer.MAX_VALUE, Integer.MAX_VALUE);

        testLongExactTwice(Integer.MAX_VALUE, -Integer.MAX_VALUE);

        testLongExactTwice(Integer.MAX_VALUE+1, Integer.MAX_VALUE+1);

        testLongExactTwice(Integer.MAX_VALUE+1, -Integer.MAX_VALUE+1);

        testLongExactTwice(Integer.MIN_VALUE-1, Integer.MIN_VALUE-1);

        testLongExactTwice(Integer.MIN_VALUE-1, -Integer.MIN_VALUE-1);

        testLongExactTwice(Integer.MIN_VALUE/2, 2);

    }

    /**

     * Test each of the exact operations with the arguments and

     * with the arguments reversed.

     * @param x

     * @param y

     */

    static void testLongExactTwice(long x, long y) {

        testLongExact(x, y);

        testLongExact(y, x);

    }

    /**

     * Test long exact arithmetic by comparing with the same operations using BigInteger

     * and checking that the result is the same as the long truncation.

     * Errors are reported with {@link fail}.

     *

     * @param x first parameter

     * @param y second parameter

     */

    static void testLongExact(long x, long y) {

        BigInteger resultBig = null;

        final BigInteger xBig = BigInteger.valueOf(x);

        final BigInteger yBig = BigInteger.valueOf(y);

        try {

            // Test addExact

            resultBig = xBig.add(yBig);

            long sum = Math.addExact(x, y);

            checkResult("long Math.addExact", x, y, sum, resultBig);

        } catch (ArithmeticException ex) {

            if (inLongRange(resultBig)) {

                fail("FAIL: long Math.addExact(" + x + " + " + y + "); Unexpected exception: " + ex);

            }

        }

        try {

            // Test subtractExact

            resultBig = xBig.subtract(yBig);

            long diff = Math.subtractExact(x, y);

            checkResult("long Math.subtractExact", x, y, diff, resultBig);

        } catch (ArithmeticException ex) {

            if (inLongRange(resultBig)) {

                fail("FAIL: long Math.subtractExact(" + x + " - " + y + ")" + "; Unexpected exception: " + ex);

            }

        }

        try {

            // Test multiplyExact

            resultBig = xBig.multiply(yBig);

            long product = Math.multiplyExact(x, y);

            checkResult("long Math.multiplyExact", x, y, product, resultBig);

        } catch (ArithmeticException ex) {

            if (inLongRange(resultBig)) {

                fail("FAIL: long Math.multiplyExact(" + x + " * " + y + ")" + "; Unexpected exception: " + ex);

            }

        }

        try {

            // Test toIntExact

            int value = Math.toIntExact(x);

            if ((long)value != x) {

                fail("FAIL: " + "long Math.toIntExact" + "(" + x + ") = " + value + "; expected an arithmetic exception: ");

            }

        } catch (ArithmeticException ex) {

            if (resultBig.bitLength() <= 32) {

                fail("FAIL: long Math.toIntExact(" + x + ")" + "; Unexpected exception: " + ex);

            }

        }

    }

    /**

     * Compare the expected and actual results.

     * @param message message for the error

     * @param x first argument

     * @param y second argument

     * @param result actual result value

     * @param expected expected result value

     */

    static void checkResult(String message, long x, long y, long result, BigInteger expected) {

        BigInteger resultBig = BigInteger.valueOf(result);

        if (!inLongRange(expected)) {

            fail("FAIL: " + message + "(" + x + ", " + y + ") = " + result + "; expected an arithmetic exception: ");

        } else if (!resultBig.equals(expected)) {

            fail("FAIL: " + message + "(" + x + ", " + y + ") = " + result + "; expected " + expected);

        }

    }

    /**

     * Check if the value fits in 64 bits (a long).

     * @param value

     * @return true if the value fits in 64 bits (including the sign).

     */

    static boolean inLongRange(BigInteger value) {

        return value.bitLength() <= 63;

    }

}