/*
 * 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.
 *
 */

package org.apache.commons.compress.archivers.tar;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import org.apache.commons.compress.archivers.zip.ZipEncoding;
import org.apache.commons.compress.archivers.zip.ZipEncodingHelper;
import org.apache.commons.compress.utils.CharsetNames;
import org.junit.Test;

public class TarUtilsTest {


    @Test
    public void testName(){
        byte [] buff = new byte[20];
        final String sb1 = "abcdefghijklmnopqrstuvwxyz";
        int off = TarUtils.formatNameBytes(sb1, buff, 1, buff.length-1);
        assertEquals(off, 20);
        String sb2 = TarUtils.parseName(buff, 1, 10);
        assertEquals(sb2,sb1.substring(0,10));
        sb2 = TarUtils.parseName(buff, 1, 19);
        assertEquals(sb2,sb1.substring(0,19));
        buff = new byte[30];
        off = TarUtils.formatNameBytes(sb1, buff, 1, buff.length-1);
        assertEquals(off, 30);
        sb2 = TarUtils.parseName(buff, 1, buff.length-1);
        assertEquals(sb1, sb2);
        buff = new byte[]{0, 1, 0};
        sb2 = TarUtils.parseName(buff, 0, 3);
        assertEquals("", sb2);
    }

    @Test
    public void testParseOctal() throws Exception{
        long value;
        byte [] buffer;
        final long MAX_OCTAL  = 077777777777L; // Allowed 11 digits
        final long MAX_OCTAL_OVERFLOW  = 0777777777777L; // in fact 12 for some implementations
        final String maxOctal = "777777777777"; // Maximum valid octal
        buffer = maxOctal.getBytes(CharsetNames.UTF_8);
        value = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(MAX_OCTAL_OVERFLOW, value);
        buffer[buffer.length - 1] = ' ';
        value = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(MAX_OCTAL, value);
        buffer[buffer.length-1]=0;
        value = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(MAX_OCTAL, value);
        buffer=new byte[]{0,0};
        value = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(0, value);
        buffer=new byte[]{0,' '};
        value = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(0, value);
        buffer=new byte[]{' ',0};
        value = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(0, value);
    }

    @Test
    public void testParseOctalInvalid() throws Exception{
        byte [] buffer;
        buffer=new byte[0]; // empty byte array
        try {
            TarUtils.parseOctal(buffer,0, buffer.length);
            fail("Expected IllegalArgumentException - should be at least 2 bytes long");
        } catch (final IllegalArgumentException expected) {
        }
        buffer=new byte[]{0}; // 1-byte array
        try {
            TarUtils.parseOctal(buffer,0, buffer.length);
            fail("Expected IllegalArgumentException - should be at least 2 bytes long");
        } catch (final IllegalArgumentException expected) {
        }
        buffer = "abcdef ".getBytes(CharsetNames.UTF_8); // Invalid input
        try {
            TarUtils.parseOctal(buffer,0, buffer.length);
            fail("Expected IllegalArgumentException");
        } catch (final IllegalArgumentException expected) {
        }
        buffer = " 0 07 ".getBytes(CharsetNames.UTF_8); // Invalid - embedded space
        try {
            TarUtils.parseOctal(buffer,0, buffer.length);
            fail("Expected IllegalArgumentException - embedded space");
        } catch (final IllegalArgumentException expected) {
        }
        buffer = " 0\00007 ".getBytes(CharsetNames.UTF_8); // Invalid - embedded NUL
        try {
            TarUtils.parseOctal(buffer,0, buffer.length);
            fail("Expected IllegalArgumentException - embedded NUL");
        } catch (final IllegalArgumentException expected) {
        }
    }

    private void checkRoundTripOctal(final long value, final int bufsize) {
        final byte [] buffer = new byte[bufsize];
        long parseValue;
        TarUtils.formatLongOctalBytes(value, buffer, 0, buffer.length);
        parseValue = TarUtils.parseOctal(buffer,0, buffer.length);
        assertEquals(value,parseValue);
    }

    private void checkRoundTripOctal(final long value) {
        checkRoundTripOctal(value, TarConstants.SIZELEN);
    }

    @Test
    public void testRoundTripOctal() {
        checkRoundTripOctal(0);
        checkRoundTripOctal(1);
//        checkRoundTripOctal(-1); // TODO What should this do?
        checkRoundTripOctal(TarConstants.MAXSIZE);
//        checkRoundTripOctal(0100000000000L); // TODO What should this do?

        checkRoundTripOctal(0, TarConstants.UIDLEN);
        checkRoundTripOctal(1, TarConstants.UIDLEN);
        checkRoundTripOctal(TarConstants.MAXID, 8);
    }

    private void checkRoundTripOctalOrBinary(final long value, final int bufsize) {
        final byte [] buffer = new byte[bufsize];
        long parseValue;
        TarUtils.formatLongOctalOrBinaryBytes(value, buffer, 0, buffer.length);
        parseValue = TarUtils.parseOctalOrBinary(buffer,0, buffer.length);
        assertEquals(value,parseValue);
    }

    @Test
    public void testRoundTripOctalOrBinary8() {
        testRoundTripOctalOrBinary(8);
    }

    @Test
    public void testRoundTripOctalOrBinary12() {
        testRoundTripOctalOrBinary(12);
        checkRoundTripOctalOrBinary(Long.MAX_VALUE, 12);
        checkRoundTripOctalOrBinary(Long.MIN_VALUE + 1, 12);
    }

    private void testRoundTripOctalOrBinary(final int length) {
        checkRoundTripOctalOrBinary(0, length);
        checkRoundTripOctalOrBinary(1, length);
        checkRoundTripOctalOrBinary(TarConstants.MAXSIZE, length); // will need binary format
        checkRoundTripOctalOrBinary(-1, length); // will need binary format
        checkRoundTripOctalOrBinary(0xffffffffffffffl, length);
        checkRoundTripOctalOrBinary(-0xffffffffffffffl, length);
    }

    // Check correct trailing bytes are generated
    @Test
    public void testTrailers() {
        final byte [] buffer = new byte[12];
        TarUtils.formatLongOctalBytes(123, buffer, 0, buffer.length);
        assertEquals(' ', buffer[buffer.length-1]);
        assertEquals('3', buffer[buffer.length-2]); // end of number
        TarUtils.formatOctalBytes(123, buffer, 0, buffer.length);
        assertEquals(0  , buffer[buffer.length-1]);
        assertEquals(' ', buffer[buffer.length-2]);
        assertEquals('3', buffer[buffer.length-3]); // end of number
        TarUtils.formatCheckSumOctalBytes(123, buffer, 0, buffer.length);
        assertEquals(' ', buffer[buffer.length-1]);
        assertEquals(0  , buffer[buffer.length-2]);
        assertEquals('3', buffer[buffer.length-3]); // end of number
    }

    @Test
    public void testNegative() throws Exception {
        final byte [] buffer = new byte[22];
        TarUtils.formatUnsignedOctalString(-1, buffer, 0, buffer.length);
        assertEquals("1777777777777777777777", new String(buffer, CharsetNames.UTF_8));
    }

    @Test
    public void testOverflow() throws Exception {
        final byte [] buffer = new byte[8-1]; // a lot of the numbers have 8-byte buffers (nul term)
        TarUtils.formatUnsignedOctalString(07777777L, buffer, 0, buffer.length);
        assertEquals("7777777", new String(buffer, CharsetNames.UTF_8));
        try {
            TarUtils.formatUnsignedOctalString(017777777L, buffer, 0, buffer.length);
            fail("Should have cause IllegalArgumentException");
        } catch (final IllegalArgumentException expected) {
        }
    }

    @Test
    public void testRoundTripNames(){
        checkName("");
        checkName("The quick brown fox\n");
        checkName("\177");
        // checkName("\0"); // does not work, because NUL is ignored
    }

    @Test
    public void testRoundEncoding() throws Exception {
        // COMPRESS-114
        final ZipEncoding enc = ZipEncodingHelper.getZipEncoding(CharsetNames.ISO_8859_1);
        final String s = "0302-0601-3\u00b1\u00b1\u00b1F06\u00b1W220\u00b1ZB\u00b1LALALA\u00b1\u00b1\u00b1\u00b1\u00b1\u00b1\u00b1\u00b1\u00b1\u00b1CAN\u00b1\u00b1DC\u00b1\u00b1\u00b104\u00b1060302\u00b1MOE.model";
        final byte buff[] = new byte[100];
        final int len = TarUtils.formatNameBytes(s, buff, 0, buff.length, enc);
        assertEquals(s, TarUtils.parseName(buff, 0, len, enc));
    }

    private void checkName(final String string) {
        final byte buff[] = new byte[100];
        final int len = TarUtils.formatNameBytes(string, buff, 0, buff.length);
        assertEquals(string, TarUtils.parseName(buff, 0, len));
    }

    @Test
    public void testReadNegativeBinary8Byte() {
        final byte[] b = new byte[] {
            (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
            (byte) 0xff, (byte) 0xff, (byte) 0xf1, (byte) 0xef,
        };
        assertEquals(-3601l, TarUtils.parseOctalOrBinary(b, 0, 8));
    }

    @Test
    public void testReadNegativeBinary12Byte() {
        final byte[] b = new byte[] {
            (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
            (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
            (byte) 0xff, (byte) 0xff, (byte) 0xf1, (byte) 0xef,
        };
        assertEquals(-3601l, TarUtils.parseOctalOrBinary(b, 0, 12));
    }


    @Test
    public void testWriteNegativeBinary8Byte() {
        final byte[] b = new byte[] {
            (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
            (byte) 0xff, (byte) 0xff, (byte) 0xf1, (byte) 0xef,
        };
        assertEquals(-3601l, TarUtils.parseOctalOrBinary(b, 0, 8));
    }

    // https://issues.apache.org/jira/browse/COMPRESS-191
    @Test
    public void testVerifyHeaderCheckSum() {
        final byte[] valid = { // from bla.tar
                116, 101, 115, 116, 49, 46, 120, 109, 108, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 48, 48, 48, 48, 54, 52, 52, 0, 48, 48, 48, 48, 55, 54, 53,
                0, 48, 48, 48, 48, 55, 54, 53, 0, 48, 48, 48, 48, 48, 48, 48,
                49, 49, 52, 50, 0, 49, 48, 55, 49, 54, 53, 52, 53, 54, 50, 54,
                0, 48, 49, 50, 50, 54, 48, 0, 32, 48, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 117, 115, 116, 97, 114, 32, 32, 0,
                116, 99, 117, 114, 100, 116, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 116, 99, 117,
                114, 100, 116, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0 };
        assertTrue(TarUtils.verifyCheckSum(valid));

        final byte[] compress117 = { // from COMPRESS-117
            (byte) 0x37, (byte) 0x7a, (byte) 0x43, (byte) 0x2e, (byte) 0x74, (byte) 0x78, (byte) 0x74, (byte) 0x00,
            0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, (byte) 0x31, (byte) 0x30, (byte) 0x30, (byte) 0x37,
            (byte) 0x37, (byte) 0x37, (byte) 0x20, (byte) 0x00, (byte) 0x20, (byte) 0x20, (byte) 0x20, (byte) 0x20,
            (byte) 0x20, (byte) 0x30, (byte) 0x20, (byte) 0x00, (byte) 0x20, (byte) 0x20, (byte) 0x20, (byte) 0x20,
            (byte) 0x20, (byte) 0x30, (byte) 0x20, (byte) 0x00, (byte) 0x20, (byte) 0x20, (byte) 0x20, (byte) 0x20,
            (byte) 0x20, (byte) 0x20, (byte) 0x31, (byte) 0x33, (byte) 0x30, (byte) 0x33, (byte) 0x33, (byte) 0x20,
            (byte) 0x31, (byte) 0x31, (byte) 0x31, (byte) 0x31, (byte) 0x35, (byte) 0x31, (byte) 0x36, (byte) 0x36,
            (byte) 0x30, (byte) 0x31, (byte) 0x36, (byte) 0x20, (byte) 0x20, (byte) 0x20, (byte) 0x35, (byte) 0x34,
            (byte) 0x31, (byte) 0x37, (byte) 0x20, (byte) 0x00, (byte) 0x30, (byte) 0x00, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        };
        assertTrue(TarUtils.verifyCheckSum(compress117));

        final byte[] invalid = { // from the testAIFF.aif file in Tika
                70, 79, 82, 77, 0, 0, 15, 46, 65, 73, 70, 70, 67, 79, 77, 77,
                0, 0, 0, 18, 0, 2, 0, 0, 3, -64, 0, 16, 64, 14, -84, 68, 0, 0,
                0, 0, 0, 0, 83, 83, 78, 68, 0, 0, 15, 8, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 1, -1, -1, 0, 1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 1, -1, -1,
                0, 0, 0, 0, 0, 0, -1, -1, 0, 2, -1, -2, 0, 2, -1, -1, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 1, -1, -1, 0, 0, -1, -1, 0, 1, 0, 0, 0, 0,
                0, 0, 0, 1, -1, -1, 0, 1, -1, -2, 0, 1, -1, -1, 0, 1, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0,
                2, -1, -2, 0, 2, -1, -1, 0, 0, 0, 1, -1, -1, 0, 1, -1, -1, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 1, -1, -2, 0, 2, -1, -2, 0, 1, 0, 0,
                0, 1, -1, -1, 0, 0, 0, 1, -1, -1, 0, 0, 0, 1, -1, -2, 0, 2,
                -1, -1, 0, 0, 0, 0, 0, 0, -1, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0, 1, -1, -1, 0, 2, -1, -2,
                0, 2, -1, -2, 0, 2, -1, -2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, -1,
                -2, 0, 2, -1, -2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                -1, -1, 0, 1, 0, 0, -1, -1, 0, 2, -1, -2, 0, 2, -1, -1, 0, 0,
                0, 0, 0, 0, -1, -1, 0, 1, -1, -1, 0, 1, -1, -1, 0, 2, -1, -2,
                0, 1, 0, 0, -1, -1, 0, 2, -1, -2, 0, 2, -1, -2, 0, 1, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, -1, 0, 0, 0,
                0, -1, -1, 0, 1, 0, 0, 0, 0, 0, 1, -1, -1, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, -2, 0, 2, -1, -1, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, -2, 0, 1, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 1, -1, -1, 0, 0, 0, 0, -1, -1, 0, 2, -1, -2,
                0, 2, -1, -2, 0, 2, -1, -1, 0, 0, 0, 0, -1, -1, 0, 1, -1, -1,
                0, 1, -1, -1, 0, 1, -1, -1, 0, 1, -1, -1, 0, 1, 0, 0, 0, 0,
                -1, -1, 0, 2, -1, -2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                1, -1, -1, 0, 0, 0, 0, -1, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 1 };
        assertFalse(TarUtils.verifyCheckSum(invalid));
    }

    @Test
    public void testParseOctalCompress330() throws Exception{
        final long expected = 0100000;
        final byte [] buffer = new byte[] {
            32, 32, 32, 32, 32, 49, 48, 48, 48, 48, 48, 32
        };
        assertEquals(expected, TarUtils.parseOctalOrBinary(buffer, 0, buffer.length));
    }

    @Test
    public void testRoundTripOctalOrBinary8_ValueTooBigForBinary() {
        try {
            checkRoundTripOctalOrBinary(Long.MAX_VALUE, 8);
            fail("Should throw exception - value is too long to fit buffer of this len");
        } catch (IllegalArgumentException e) {
            assertEquals("Value 9223372036854775807 is too large for 8 byte field.", e.getMessage());
        }
    }

    @Test
    public void testParseSparse() {
        final long expectedOffset = 0100000;
        final long expectedNumbytes = 0111000;
        final byte [] buffer = new byte[] {
                ' ', ' ', ' ', ' ', ' ', '0', '1', '0', '0', '0', '0', '0', // sparseOffset
                ' ', ' ', ' ', ' ', ' ', '0', '1', '1', '1', '0', '0', '0'};
        TarArchiveStructSparse sparse = TarUtils.parseSparse(buffer, 0);
        assertEquals(sparse.getOffset(), expectedOffset);
        assertEquals(sparse.getNumbytes(), expectedNumbytes);
    }

}
