/*
 * Zorbage: an algebraic data hierarchy for use in numeric processing.
 *
 * Copyright (C) 2016-2018 Barry DeZonia
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package nom.bdezonia.zorbage.algorithm;

import nom.bdezonia.zorbage.type.algebra.Group;
import nom.bdezonia.zorbage.type.algebra.Ordered;
import nom.bdezonia.zorbage.type.storage.IndexedDataSource;

/**
 * 
 * @author Barry DeZonia
 *
 */
public class BinarySearch {

	private BinarySearch() {
		// do not instantiate
	}
	
	/**
	 * Search a list that is sorted in ascending order for a given value.
	 * Return the index within the list where the value is found. Return
	 * -1 if the element is not found.
	 * 
	 * @param group
	 * @param data
	 * @param start
	 * @param count
	 * @param value
	 * @return
	 */
	public static <T extends Group<T,U> & Ordered<U>, U>
		long compute(T group, IndexedDataSource<?,U> data, long start, long count, U value)
	{
		U tmp = group.construct();
		long lo = 0;
		long hi = count-1;
		while (hi >= lo) {
			long mid = (lo + hi) / 2;
			data.get(start+mid, tmp);
			int cmp = group.compare(tmp, value);
			if (cmp == 0)
				return start + mid;
			else if (cmp < 0)
				lo = mid + 1;
			else // cmp > 0
				hi = mid - 1;
		}
		return -1;
	}
}

Add a binary search algorithm
Add a binary search algorithm
