Java Array xor xorI(long[] v, long[] o)

Description

XOR o onto v inplace, i.e.

License

Open Source License

Parameter

Parameter	Description
v	Primary object
o	data to xor

Return

v

Declaration

public static long[] xorI(long[] v, long[] o) 

Method Source Code

//package com.java2s;
/*/*  w  ww  . j a  v a 2s .  co m*/
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures
    
 Copyright (C) 2015
 Ludwig-Maximilians-Universit?t M?nchen
 Lehr- und Forschungseinheit f?r Datenbanksysteme
 ELKI Development Team
    
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
    
 This program 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 Affero General Public License for more details.
    
 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

public class Main {
    /**
     * Shift factor for a long: 2^6 == 64 == Long.SIZE
     */
    private static final int LONG_LOG2_SIZE = 6;
    /** Masking for long shifts. */
    private static final int LONG_LOG2_MASK = 0x3f;

    /**
     * XOR o onto v inplace, i.e. v ^= o
     * 
     * @param v Primary object
     * @param o data to xor
     * @return v
     */
    public static long[] xorI(long[] v, long[] o) {
        assert (o.length <= v.length) : "Bit set sizes do not agree.";
        for (int i = 0; i < o.length; i++) {
            v[i] ^= o[i];
        }
        return v;
    }

    /**
     * XOR o onto v inplace, i.e. v ^= (o << off)
     * 
     * @param v Primary object
     * @param o data to or
     * @param off Offset
     * @return v
     */
    public static long[] xorI(long[] v, long[] o, int off) {
        if (off == 0) {
            return xorI(v, o);
        }
        if (off < 0) {
            throw new UnsupportedOperationException("Negative shifts are not supported.");
        }
        // Break shift into integers to shift and bits to shift
        final int shiftWords = off >>> LONG_LOG2_SIZE;
        final int shiftBits = off & LONG_LOG2_MASK;

        if (shiftWords >= v.length) {
            return v;
        }
        // Simple case - multiple of word size
        if (shiftBits == 0) {
            final int end = Math.min(v.length, o.length + shiftWords);
            for (int i = shiftWords; i < end; i++) {
                v[i] ^= o[i - shiftWords];
            }
            return v;
        }
        // Overlapping case
        final int unshiftBits = Long.SIZE - shiftBits;
        final int end = Math.min(v.length, o.length + shiftWords) - 1;
        for (int i = end; i > shiftWords; i--) {
            final int src = i - shiftWords;
            v[i] ^= (o[src] << shiftBits) | (o[src - 1] >>> unshiftBits);
        }
        v[shiftWords] ^= o[0] << shiftBits;
        return v;
    }
}

Related

1. xorByteArrays(byte[] first, byte[] second)
2. xorBytes(byte[] data, byte[] key)
3. xorData(final byte[] data, final byte[] passBytes)
4. xorDecode(byte[] str, char[] key)
5. xorend(byte[] in1, byte[] in2)
6. xorTwoByteArrays(byte[] byteArray1, byte[] byteArray2)