Java Number Negate negate(int[] input)

Description

negate

License

Open Source License

Declaration

public static int[] negate(int[] input) 

Method Source Code

//package com.java2s;
/*/*from   ww w . ja  v  a  2  s . co m*/
 * Copyright (c) 2009 Stephan Schloepke and innoQ Deutschland GmbH
 *
 * Stephan Schloepke: http://www.schloepke.de/
 * innoQ Deutschland GmbH: http://www.innoq.com/
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

public class Main {
    public static final int[] ZERO_INT_ARRAY = new int[0];
    public static final byte[] ZERO_BYTE_ARRAY = new byte[0];

    public static int[] negate(int[] input) {
        int x = input[0];
        int j = input.length;
        if (x == 0) {
            // if we have a carry propagation it is possible we raise for one element
            // actually this should rarely happens since it only does happens if the input
            // is not stripped or the follow up is exactly -1 so that a propagation occurs.
            j++;
        } else if (x < 0 && (x >>> 1) > 0) {
            j++;
        }
        int[] result = new int[j];
        int i = input.length;
        boolean carry = true;
        while (i > 0 && carry) {
            result[--j] = (~input[--i]) + 1;
            carry = result[j] == 0;
        }
        while (i > 0) {
            result[--j] = ~input[--i];
        }
        if (j > 0 && carry) {
            result[--j] = 1;
        } else if (j > 0 || result[j] == 0) {
            // we need to shrink the array
            j = 0;
            while (j < result.length && result[j] == 0) {
                j++;
            }
            if (result.length == j) {
                return ZERO_INT_ARRAY;
            }
            if (result[j] < 0) {
                j--;
            }
            if (j > 0) {
                int[] t = new int[result.length - j];
                System.arraycopy(result, j, t, 0, t.length);
                return t;
            }
        }
        return result;
    }

    public static byte[] negate(byte[] input) {
        int x = input[0];
        int j = input.length;
        if (x == 0) {
            // if we have a carry propagation it is possible we raise for one element
            // actually this should rarely happens since it only does happens if the input
            // is not stripped or the follow up is exactly -1 so that a propagation occurs.
            j++;
        } else if (x < 0 && (x >>> 1) > 0) {
            j++;
        }
        byte[] result = new byte[j];
        int i = input.length;
        boolean carry = true;
        while (i > 0 && carry) {
            result[--j] = (byte) ((~input[--i]) + 1);
            carry = result[j] == 0;
        }
        while (i > 0) {
            result[--j] = (byte) ~input[--i];
        }
        if (j > 0 && carry) {
            result[--j] = 1;
        } else if (j > 0 || result[j] == 0) {
            // we need to shrink the array
            j = 0;
            while (j < result.length && result[j] == 0) {
                j++;
            }
            if (result.length == j) {
                return ZERO_BYTE_ARRAY;
            }
            if (result[j] < 0) {
                j--;
            }
            if (j > 0) {
                byte[] t = new byte[result.length - j];
                System.arraycopy(result, j, t, 0, t.length);
                return t;
            }
        }
        return result;
    }
}

Related

1. negate(double[] a)
2. negate(double[] output, double[] a)
3. negate(double[] values)
4. negate(final Boolean bool)
5. negate(int[] ar)
6. negate(int[] x, int Max)
7. negate(String expr)
8. negate(String string, String trueValue, String falseValue)
9. negate(String value)