ArrayCompare.java

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class ArrayCompare {

	public static int compare(byte[] lefts, byte[] rights) {
		if (lefts == rights) {
			return 0;
		}
		if ((lefts != null) && (rights == null)) {
			return 1;
		}
		if ((lefts == null) && (rights != null)) {
			return -1;
		}
		int ll = lefts.length;
		int rl = rights.length;
		int min = Math.min(ll, rl);
		for (int i = 0; i < min; i++) {
			byte lb = lefts[i];
			byte rb = rights[i];
			if (lb < rb) {
				return -1;
			}
			if (lb > rb) {
				return 1;
			}
		}
		return ll - rl;
	}

	@Test
	public void testCompare() throws Exception {
		assertEquals(0, compare(null, null));
		assertEquals(-1, compare(null, new byte[0]));
		assertEquals(1, compare(new byte[0], null));
		assertEquals(-1, compare(new byte[0], new byte[1]));
		assertEquals(1, compare(new byte[1], new byte[0]));
		assertEquals(0, compare(new byte[] { 1 }, new byte[] { 1 }));
		assertEquals(1, compare(new byte[] { 1, 2 }, new byte[] { 1, 1 }));
		byte[] aa = new byte[] { 'a', 'a' };
		byte[] zzzz = new byte[] { 'z', 'z', 'z', 'z' };
		assertEquals(-1, compare(aa, zzzz));
	}
}