ICSharpCode.SharpZipLib.Zip.ZipExtraData.GetStreamForTag C# (CSharp) Method

        public Stream GetStreamForTag(int tag) {
            Stream result=null;
            if (Find(tag)) {
                result=new MemoryStream(_data, _index, _readValueLength, false);
            }
            return result;
        }

        public void BasicOperations()
        {
            ZipExtraData zed = new ZipExtraData(null);
            Assert.AreEqual(0, zed.Length);

            zed = new ZipExtraData(new byte[] { 1, 0, 0, 0 });
            Assert.AreEqual(4, zed.Length, "A length should be 4");

            ZipExtraData zed2 = new ZipExtraData();
            Assert.AreEqual(0, zed2.Length);

            zed2.AddEntry(1, new byte[] { });

            byte[] data = zed.GetEntryData();
            for (int i = 0; i < data.Length; ++i) {
                Assert.AreEqual(zed2.GetEntryData()[i], data[i]);
            }

            Assert.AreEqual(4, zed2.Length, "A1 length should be 4");

            bool findResult = zed.Find(2);
            Assert.IsFalse(findResult, "A - Shouldnt find tag 2");

            findResult = zed.Find(1);
            Assert.IsTrue(findResult, "A - Should find tag 1");
            Assert.AreEqual(0, zed.ValueLength, "A- Length of entry should be 0");
            Assert.AreEqual(-1, zed.ReadByte());
            Assert.AreEqual(0, zed.GetStreamForTag(1).Length, "A - Length of stream should be 0");

            zed = new ZipExtraData(new byte[] { 1, 0, 3, 0, 1, 2, 3 });
            Assert.AreEqual(7, zed.Length, "Expected a length of 7");

            findResult = zed.Find(1);
            Assert.IsTrue(findResult, "B - Should find tag 1");
            Assert.AreEqual(3, zed.ValueLength, "B - Length of entry should be 3");
            for (int i = 1; i <= 3; ++i) {
                Assert.AreEqual(i, zed.ReadByte());
            }
            Assert.AreEqual(-1, zed.ReadByte());

            Stream s = zed.GetStreamForTag(1);
            Assert.AreEqual(3, s.Length, "B.1 Stream length should be 3");
            for (int i = 1; i <= 3; ++i) {
                Assert.AreEqual(i, s.ReadByte());
            }
            Assert.AreEqual(-1, s.ReadByte());

            zed = new ZipExtraData(new byte[] { 1, 0, 3, 0, 1, 2, 3, 2, 0, 1, 0, 56 });
            Assert.AreEqual(12, zed.Length, "Expected a length of 12");

            findResult = zed.Find(1);
            Assert.IsTrue(findResult, "C.1 - Should find tag 1");
            Assert.AreEqual(3, zed.ValueLength, "C.1 - Length of entry should be 3");
            for (int i = 1; i <= 3; ++i) {
                Assert.AreEqual(i, zed.ReadByte());
            }
            Assert.AreEqual(-1, zed.ReadByte());

            findResult = zed.Find(2);
            Assert.IsTrue(findResult, "C.2 - Should find tag 2");
            Assert.AreEqual(1, zed.ValueLength, "C.2 - Length of entry should be 1");
            Assert.AreEqual(56, zed.ReadByte());
            Assert.AreEqual(-1, zed.ReadByte());

            s = zed.GetStreamForTag(2);
            Assert.AreEqual(1, s.Length);
            Assert.AreEqual(56, s.ReadByte());
            Assert.AreEqual(-1, s.ReadByte());

            zed = new ZipExtraData();
            zed.AddEntry(7, new byte[] { 33, 44, 55 });
            findResult = zed.Find(7);
            Assert.IsTrue(findResult, "Add.1 should find new tag");
            Assert.AreEqual(3, zed.ValueLength, "Add.1 length should be 3");
            Assert.AreEqual(33, zed.ReadByte());
            Assert.AreEqual(44, zed.ReadByte());
            Assert.AreEqual(55, zed.ReadByte());
            Assert.AreEqual(-1, zed.ReadByte());

            zed.AddEntry(7, null);
            findResult = zed.Find(7);
            Assert.IsTrue(findResult, "Add.2 should find new tag");
            Assert.AreEqual(0, zed.ValueLength, "Add.2 length should be 0");

            zed.StartNewEntry();
            zed.AddData(0xae);
            zed.AddNewEntry(55);

            findResult = zed.Find(55);
            Assert.IsTrue(findResult, "Add.3 should find new tag");
            Assert.AreEqual(1, zed.ValueLength, "Add.3 length should be 1");
            Assert.AreEqual(0xae, zed.ReadByte());
            Assert.AreEqual(-1, zed.ReadByte());

            zed = new ZipExtraData();
            zed.StartNewEntry();
            zed.AddLeLong(0);
            zed.AddLeLong(-4);
            zed.AddLeLong(-1);
            zed.AddLeLong(long.MaxValue);
            zed.AddLeLong(long.MinValue);
            zed.AddLeLong(0x123456789ABCDEF0);
            zed.AddLeLong(unchecked((long)0xFEDCBA9876543210));
            zed.AddNewEntry(567);

            s = zed.GetStreamForTag(567);
            long longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(0, longValue, "Expected long value of zero");

            longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(-4, longValue, "Expected long value of -4");

            longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(-1, longValue, "Expected long value of -1");

            longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(long.MaxValue, longValue, "Expected long value of MaxValue");

            longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(long.MinValue, longValue, "Expected long value of MinValue");

            longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(0x123456789abcdef0, longValue, "Expected long value of MinValue");

            longValue = ReadLong(s);
            Assert.AreEqual(longValue, zed.ReadLong(), "Read/stream mismatch");
            Assert.AreEqual(unchecked((long)0xFEDCBA9876543210), longValue, "Expected long value of MinValue");
        }