binary Search object array - Android java.lang

Android examples for java.lang:array

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Description

binary Search object array

Demo Code

/*/*  www.java2 s.c o  m*/
 * @(#)$Id: ArrayUtils.java 3619 2008-03-26 07:23:03Z yui $
 * 
 * Copyright 2006-2008 Makoto YUI
 * 
 * Licensed 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.
 * 
 * Contributors: Makoto YUI - ported from jakarta commons lang
 */
//package com.java2s;

public class Main {
    public static int binarySearch(final Object[] a, final int fromIndex,
            final int toIndex, final Object key) {
        int low = fromIndex;
        int high = toIndex - 1;

        while (low <= high) {
            int mid = (low + high) >>> 1;
            Comparable midVal = (Comparable) a[mid];
            int cmp = midVal.compareTo(key);

            if (cmp < 0) {
                low = mid + 1;
            } else if (cmp > 0) {
                high = mid - 1;
            } else {
                return mid; // key found
            }
        }
        return -(low + 1); // key not found.
    }

    public static int compareTo(final byte lhs[], final byte rhs[]) {
        if (lhs == rhs) {
            return 0;
        }
        final int len = Math.min(lhs.length, rhs.length);
        for (int i = 0; i < len; i++) {
            if (lhs[i] != rhs[i]) {
                return (lhs[i] & 0xFF) - (rhs[i] & 0xFF);
            }
        }
        return lhs.length - rhs.length;
    }

    public static int compareTo(final byte lhs[], final byte rhs[],
            final int offset) {
        final int len = Math.min(lhs.length, rhs.length);
        for (int i = offset; i < len; i++) {
            if (lhs[i] != rhs[i]) {
                return (lhs[i] & 0xFF) - (rhs[i] & 0xFF);
            }
        }
        return lhs.length - rhs.length;
    }

    public static int compareTo(final byte lhs[], final byte rhs[],
            final int offset, final int length) {
        int tolen = offset + length;
        final int limit = Math.min(Math.min(lhs.length, rhs.length), tolen);
        for (int i = offset; i < limit; i++) {
            if (lhs[i] != rhs[i]) {
                return (lhs[i] & 0xFF) - (rhs[i] & 0xFF);
            }
        }
        return 0;
    }
}

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