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/*
 * Zorbage: an algebraic data hierarchy for use in numeric processing.
 *
 * Copyright (c) 2016-2021 Barry DeZonia All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 * Redistributions of source code must retain the above copyright notice, this list
 * of conditions and the following disclaimer.
 * 
 * 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.
 * 
 * Neither the name of the  nor the names of its contributors may
 * be used to endorse or promote products derived from this software without specific
 * prior written permission.
 * 
 * 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  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.algebra.Algebra;
import nom.bdezonia.zorbage.algebra.Ordered;
import nom.bdezonia.zorbage.datasource.IndexedDataSource;

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

	// do not instantiate
	
	private LexicographicalCompare() { }
	
	/**
	 * LexicographicalCompare compares two lists treating them as tuples of values.
	 * The comparison returns true if the 1st "tuple" is less than the 2nd "tuple".
	 * Less than is defined as lexicographically less than.
	 * 
	 * @param alg
	 * @param a
	 * @param b
	 * @return
	 */
	public static  & Ordered, U>
		boolean compute(T alg, IndexedDataSource a, IndexedDataSource b)
	{
		long aSize = a.size();
		long bSize = b.size();
		long minSize = Math.min(aSize, bSize);
		U tmpA = alg.construct();
		U tmpB = alg.construct();
		for (long i = 0; i < minSize; i++) {
			a.get(i, tmpA);
			b.get(i, tmpB);
			if (alg.isLess().call(tmpA, tmpB))
				return true;
			else if (alg.isGreater().call(tmpA, tmpB))
				return false;
		}
		// if here the two sequences match in 1st minSize elements.
		if (aSize < bSize)
			return true;
		else
			return false;
	}
}