Android Long Overflow Check addAndCheck(long a, long b)

Description

Add two long integers, checking for overflow.

License

Apache License

Parameter

Parameter	Description
a	an addend
b	an addend

Exception

Parameter	Description
MathArithmeticException	if the result can not be represented as anlong

Return

the sum a+b

Declaration

public static long addAndCheck(long a, long b)
        throws MathArithmeticException 

Method Source Code

/*// ww  w  . j  a  v a 2s  .  c o m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.math.BigInteger;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.commons.math3.exception.MathArithmeticException;
import org.apache.commons.math3.exception.NotPositiveException;
import org.apache.commons.math3.exception.NumberIsTooLargeException;
import org.apache.commons.math3.exception.util.Localizable;
import org.apache.commons.math3.exception.util.LocalizedFormats;

public class Main{
    /**
     * Add two integers, checking for overflow.
     *
     * @param x an addend
     * @param y an addend
     * @return the sum {@code x+y}
     * @throws MathArithmeticException if the result can not be represented
     * as an {@code int}.
     * @since 1.1
     */
    public static int addAndCheck(int x, int y)
            throws MathArithmeticException {
        long s = (long) x + (long) y;
        if (s < Integer.MIN_VALUE || s > Integer.MAX_VALUE) {
            throw new MathArithmeticException(
                    LocalizedFormats.OVERFLOW_IN_ADDITION, x, y);
        }
        return (int) s;
    }
    /**
     * Add two long integers, checking for overflow.
     *
     * @param a an addend
     * @param b an addend
     * @return the sum {@code a+b}
     * @throws MathArithmeticException if the result can not be represented as an
     *         long
     * @since 1.2
     */
    public static long addAndCheck(long a, long b)
            throws MathArithmeticException {
        return ArithmeticUtils.addAndCheck(a, b,
                LocalizedFormats.OVERFLOW_IN_ADDITION);
    }
    /**
     * Add two long integers, checking for overflow.
     *
     * @param a Addend.
     * @param b Addend.
     * @param pattern Pattern to use for any thrown exception.
     * @return the sum {@code a + b}.
     * @throws MathArithmeticException if the result cannot be represented
     * as a {@code long}.
     * @since 1.2
     */
    private static long addAndCheck(long a, long b, Localizable pattern)
            throws MathArithmeticException {
        long ret;
        if (a > b) {
            // use symmetry to reduce boundary cases
            ret = addAndCheck(b, a, pattern);
        } else {
            // assert a <= b

            if (a < 0) {
                if (b < 0) {
                    // check for negative overflow
                    if (Long.MIN_VALUE - b <= a) {
                        ret = a + b;
                    } else {
                        throw new MathArithmeticException(pattern, a, b);
                    }
                } else {
                    // opposite sign addition is always safe
                    ret = a + b;
                }
            } else {
                // assert a >= 0
                // assert b >= 0

                // check for positive overflow
                if (a <= Long.MAX_VALUE - b) {
                    ret = a + b;
                } else {
                    throw new MathArithmeticException(pattern, a, b);
                }
            }
        }
        return ret;
    }
}

Related

1. addAndCheck(long a, long b, Localizable pattern)
2. mulAndCheck(long a, long b)
3. subAndCheck(long a, long b)