/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

//
// Log4j uses the JUnit framework for internal unit testing. JUnit
// available from
//
//     http://www.junit.org

package org.apache.log4j.helpers;

import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.Logger;
import org.apache.log4j.Level;

import junit.framework.TestCase;
import junit.framework.TestSuite;
import junit.framework.Test;

/**
 * Unit test the {@link CyclicBuffer}.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * 
 */
public class CyclicBufferTestCase extends TestCase {

    static Logger cat = Logger.getLogger("x");

    static int MAX = 1000;

    static LoggingEvent[] e = new LoggingEvent[MAX];

    {
	for (int i = 0; i < MAX; i++) {
	    e[i] = new LoggingEvent("", cat, Level.DEBUG, "e" + i, null);
	}
    }

    public CyclicBufferTestCase(String name) {
	super(name);
    }

    public void setUp() {

    }

    public void test0() {
	int size = 2;

	CyclicBuffer cb = new CyclicBuffer(size);
	assertEquals(cb.getMaxSize(), size);

	cb.add(e[0]);
	assertEquals(cb.length(), 1);
	assertEquals(cb.get(), e[0]);
	assertEquals(cb.length(), 0);
	assertNull(cb.get());
	assertEquals(cb.length(), 0);

	cb = new CyclicBuffer(size);
	cb.add(e[0]);
	cb.add(e[1]);
	assertEquals(cb.length(), 2);
	assertEquals(cb.get(), e[0]);
	assertEquals(cb.length(), 1);
	assertEquals(cb.get(), e[1]);
	assertEquals(cb.length(), 0);
	assertNull(cb.get());
	assertEquals(cb.length(), 0);

    }

    /**
     * Test a buffer of size 1,2,4,8,..,128
     */
    public void test1() {
	for (int bufSize = 1; bufSize <= 128; bufSize *= 2)
	    doTest1(bufSize);
    }

    void doTest1(int size) {
	// System.out.println("Doing test with size = "+size);
	CyclicBuffer cb = new CyclicBuffer(size);

	assertEquals(cb.getMaxSize(), size);

	for (int i = -(size + 10); i < (size + 10); i++) {
	    assertNull(cb.get(i));
	}

	for (int i = 0; i < MAX; i++) {
	    cb.add(e[i]);
	    int limit = i < size - 1 ? i : size - 1;

	    // System.out.println("\nLimit is " + limit + ", i="+i);

	    for (int j = limit; j >= 0; j--) {
		// System.out.println("i= "+i+", j="+j);
		assertEquals(cb.get(j), e[i - (limit - j)]);
	    }
	    assertNull(cb.get(-1));
	    assertNull(cb.get(limit + 1));
	}
    }

    public void testResize() {
	for (int isize = 1; isize <= 128; isize *= 2) {
	    doTestResize(isize, isize / 2 + 1, isize / 2 + 1);
	    doTestResize(isize, isize / 2 + 1, isize + 10);
	    doTestResize(isize, isize + 10, isize / 2 + 1);
	    doTestResize(isize, isize + 10, isize + 10);
	}
    }

    void doTestResize(int initialSize, int numberOfAdds, int newSize) {
	// System.out.println("initialSize = "+initialSize+", numberOfAdds="
	// +numberOfAdds+", newSize="+newSize);
	CyclicBuffer cb = new CyclicBuffer(initialSize);
	for (int i = 0; i < numberOfAdds; i++) {
	    cb.add(e[i]);
	}
	cb.resize(newSize);

	int offset = numberOfAdds - initialSize;
	if (offset < 0)
	    offset = 0;

	int len = newSize < numberOfAdds ? newSize : numberOfAdds;
	len = len < initialSize ? len : initialSize;
	// System.out.println("Len = "+len+", offset="+offset);
	for (int j = 0; j < len; j++) {
	    assertEquals(cb.get(j), e[offset + j]);
	}

    }

    public static Test suite() {
	TestSuite suite = new TestSuite();
	suite.addTest(new CyclicBufferTestCase("test0"));
	suite.addTest(new CyclicBufferTestCase("test1"));
	suite.addTest(new CyclicBufferTestCase("testResize"));
	return suite;
    }
}
