Android example source code file (ChecksumTest.java)

This example Android source code file (ChecksumTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

adler32, android, checksums, checksumtest, crc32, exception, smalltest, test, testcase, zip

The ChecksumTest.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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 android.core;

import junit.framework.TestCase;

import java.util.zip.Adler32;
import java.util.zip.CRC32;
import android.test.suitebuilder.annotation.SmallTest;

/**
 * tests for CRC32 and Adler32 checksum algorithms.
 */
public class ChecksumTest extends TestCase {

    @SmallTest
    public void testChecksum() throws Exception {
        /*
         * Values computed experimentally, using C interfaces.
         */
        adler32Test(mTestString, 0x9de210dbL);
        cRC32Test(mTestString, 0x939f04afL);

        // Test for issue 1016037
        wrongChecksumWithAdler32Test();
    }

    private void adler32Test(byte[] values, long expected) {
        Adler32 adler = new Adler32();

        // try it all at once
        adler.update(values);
        assertEquals(adler.getValue(), expected);

        // try resetting and computing one byte at a time
        adler.reset();
        for (int i = 0; i < values.length; i++) {
            adler.update(values[i]);
        }
        assertEquals(adler.getValue(), expected);
    }

    private void cRC32Test(byte[] values, long expected) {
        CRC32 crc = new CRC32();

        // try it all at once
        crc.update(values);
        assertEquals(crc.getValue(), expected);

        // try resetting and computing one byte at a time
        crc.reset();
        for (int i = 0; i < values.length; i++) {
            crc.update(values[i]);
        }
        assertEquals(crc.getValue(), expected);
    }

    // "The quick brown fox jumped over the lazy dogs\n"
    private static byte[] mTestString = {
            0x54, 0x68, 0x65, 0x20, 0x71, 0x75, 0x69, 0x63,
            0x6b, 0x20, 0x62, 0x72, 0x6f, 0x77, 0x6e, 0x20,
            0x66, 0x6f, 0x78, 0x20, 0x6a, 0x75, 0x6d, 0x70,
            0x65, 0x64, 0x20, 0x6f, 0x76, 0x65, 0x72, 0x20,
            0x74, 0x68, 0x65, 0x20, 0x6c, 0x61, 0x7a, 0x79,
            0x20, 0x64, 0x6f, 0x67, 0x73, 0x2e, 0x0a
    };


    // Test for issue 1016037
    private void wrongChecksumWithAdler32Test() {
        byte[] bytes = {1, 0, 5, 0, 15, 0, 1, 11, 0, 1};
        Adler32 adler = new Adler32();
        adler.update(bytes);
        long arrayChecksum = adler.getValue();
        adler.reset();
        for (int i = 0; i < bytes.length; i++) {
            adler.update(bytes[i]);
        }
        assertEquals("Checksums not equal: expected: " + arrayChecksum +
                " actual: " + adler.getValue(), arrayChecksum, adler.getValue());
    }
}