BitReversalsTest.java

/*
 * 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.
 */

package com.addthis.basis.util;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static com.addthis.basis.util.BitReversals.stackOverflowMethod;

public class BitReversalsTest {

    private static final Logger log = LoggerFactory.getLogger(BitReversalsTest.class);

    @Test
    public void consistency() {
        for (int i = 0; i < 999999; i++) {
            int jdkReversed = Integer.reverse(i);
            int basisReversed = Bytes.reverseBits(i);
            int stackReversed = stackOverflowMethod(i);
            boolean consistent =
                    (jdkReversed == basisReversed) &&
                    (jdkReversed == stackReversed);
            if (!consistent) {
                log.error("not consistent int {} jdk {} basis {} stack {}", i,
                          jdkReversed,
                          basisReversed, stackReversed);
                throw new RuntimeException("not consistent");
            }
        }
    }
}