hyracks-dataflow-common/src/main/java/edu/uci/ics/hyracks/dataflow/common/data/comparators/UTF8StringBinaryComparatorFactory.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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.
 */
package edu.uci.ics.hyracks.dataflow.common.data.comparators;

import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
import edu.uci.ics.hyracks.dataflow.common.data.util.StringUtils;

public class UTF8StringBinaryComparatorFactory implements IBinaryComparatorFactory {
    private static final long serialVersionUID = 1L;

    public static final UTF8StringBinaryComparatorFactory INSTANCE = new UTF8StringBinaryComparatorFactory();

    private UTF8StringBinaryComparatorFactory() {
    }

    @Override
    public IBinaryComparator createBinaryComparator() {
        return new IBinaryComparator() {
            @Override
            public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
                int utflen1 = StringUtils.getUTFLen(b1, s1);
                int utflen2 = StringUtils.getUTFLen(b2, s2);

                int c1 = 0;
                int c2 = 0;

                int s1Start = s1 + 2;
                int s2Start = s2 + 2;

                while (c1 < utflen1 && c2 < utflen2) {
                    char ch1 = StringUtils.charAt(b1, s1Start + c1);
                    char ch2 = StringUtils.charAt(b2, s2Start + c2);

                    if (ch1 != ch2) {
                        return ch1 - ch2;
                    }
                    c1 += StringUtils.charSize(b1, s1Start + c1);
                    c2 += StringUtils.charSize(b2, s2Start + c2);
                }
                return utflen1 - utflen2;
            }
        };
    }
}