public void Gzip_Flush()
{
// Verify behavior of flushing a compression stream
using (MemoryStream compressed = new MemoryStream())
{
using (GzipWriter stream = new GzipWriter(compressed, true))
{
stream.Write(s_sampledata, 0, s_sampledata.Length);
// Get the unflushed length of the compressed stream and flush it
long unflushed = compressed.Length;
stream.Flush();
// The expectation is that the output stream will be longer after the flush
long flushedonce = compressed.Length;
Assert.IsTrue(compressed.Length > unflushed);
// Flushing the same data a second time should not have any impact at all
stream.Flush();
Assert.AreEqual(compressed.Length, flushedonce);
// The stream should still be writable after a flush operation
stream.Write(s_sampledata, 0, s_sampledata.Length / 10);
}
}
// Verify behavior of flushing a decompression stream
using (GzipReader stream = new GzipReader(new MemoryStream(s_sampledata)))
{
// Flush has no effect on decompression streams, just ensure it doesn't throw
stream.Flush();
}
}
public void Gzip_CompressExternal()
{
// This method generates an output file that can be tested externally; "thethreemusketeers.txt" is
// set to Copy Always to the output directory, it can be diffed after running the external tool
using (GzipWriter writer = new GzipWriter(File.Create(Path.Combine(Environment.CurrentDirectory, "thethreemusketeers.gz"))))
{
writer.Write(s_sampledata);
writer.Flush();
}
}
public void Gzip_CompressionLevel()
{
using (MemoryStream source = new MemoryStream(s_sampledata))
{
long none, fastest, optimal; // Size of compressed streams
// Compress using CompressionLevel.NoCompression
using (MemoryStream compressed = new MemoryStream())
{
using (GzipWriter compressor = new GzipWriter(compressed, CompressionLevel.NoCompression))
{
compressor.Write(s_sampledata, 0, s_sampledata.Length);
compressor.Flush();
none = compressed.Length;
}
}
// Compress using CompressionLevel.Fastest
using (MemoryStream compressed = new MemoryStream())
{
using (GzipWriter compressor = new GzipWriter(compressed, CompressionLevel.Fastest))
{
compressor.Write(s_sampledata, 0, s_sampledata.Length);
compressor.Flush();
fastest = compressed.Length;
}
}
// Compress using CompressionLevel.Optimal
using (MemoryStream compressed = new MemoryStream())
{
using (GzipWriter compressor = new GzipWriter(compressed, CompressionLevel.Optimal))
{
compressor.Write(s_sampledata, 0, s_sampledata.Length);
compressor.Flush();
optimal = compressed.Length;
}
}
// Fastest should produce better results than no compression
Assert.IsTrue(fastest < none);
// Optimal should produce better results than fastest
Assert.IsTrue(optimal < fastest);
// Fastest should be smaller than the original length
Assert.IsTrue(fastest < source.Length);
// No compression should be BIGGER than the original length
Assert.IsTrue(source.Length < none);
}
}
public void Gzip_GzipException()
{
using (MemoryStream compressed = new MemoryStream())
{
// Start with a compressed MemoryStream created from the sample data
using (GzipWriter compressor = new GzipWriter(compressed, CompressionLevel.Optimal, true))
{
compressor.Write(s_sampledata, 0, s_sampledata.Length);
compressor.Flush();
}
byte[] buffer = new byte[8192];
GzipException thrown = null;
GzipException deserialized = null;
// Create a decompressor to test exception cases
using (GzipReader decompressor = new GzipReader(compressed, true))
{
// Attempting to read from the middle of the compressed stream should throw a GzipException
compressed.Position = compressed.Length / 2;
try { decompressor.Read(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (GzipException ex) { thrown = ex; }
Assert.IsNotNull(thrown);
Assert.IsInstanceOfType(thrown, typeof(GzipException));
// Check the error code property
Assert.AreEqual(-3, thrown.ErrorCode); // Z_DATA_ERROR (-3)
// Serialize and de-serialize the exception with a BinaryFormatter
BinaryFormatter formatter = new BinaryFormatter();
using (MemoryStream memstream = new MemoryStream())
{
formatter.Serialize(memstream, thrown);
memstream.Seek(0, 0);
deserialized = (GzipException)formatter.Deserialize(memstream);
}
// Check that the exceptions are equivalent
Assert.AreEqual(thrown.ErrorCode, deserialized.ErrorCode);
Assert.AreEqual(thrown.StackTrace, deserialized.StackTrace);
Assert.AreEqual(thrown.ToString(), deserialized.ToString());
}
}
}
public void Gzip_Write()
{
byte[] buffer = new byte[8192]; // 8KiB data buffer
// Compress the sample data using a call to Write directly
using (MemoryStream compressed = new MemoryStream())
{
// Check the constructor for ArgumentNullException while we're here
try { using (GzipWriter compressor = new GzipWriter(null)) { }; Assert.Fail("Constructor should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentNullException)); }
using (GzipWriter compressor = new GzipWriter(compressed, CompressionLevel.Optimal, true))
{
// Send in some bum arguments to Write() to check they are caught
try { compressor.Write(null); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentNullException)); }
try { compressor.Write(null, 0, 0); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentNullException)); }
try { compressor.Write(s_sampledata, -1, 0); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentOutOfRangeException)); }
try { compressor.Write(s_sampledata, 0, -1); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentOutOfRangeException)); }
try { compressor.Write(s_sampledata, 0, s_sampledata.Length + 1024); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentException)); }
// Not writing anything shouldn't throw an exception
compressor.Write(s_sampledata, 0, 0);
// Compress the data; there really isn't much that can go wrong with Write() itself
compressor.Write(s_sampledata, 0, s_sampledata.Length);
compressor.Flush();
}
using (GzipReader reader = new GzipReader(compressed, true))
{
try { reader.Write(buffer, 0, buffer.Length); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(NotSupportedException)); }
}
}
}
public void Gzip_Read()
{
byte[] buffer = new byte[8192]; // 8KiB data buffer
using (MemoryStream compressed = new MemoryStream())
{
// Start with a compressed MemoryStream created from the sample data
using (GzipWriter compressor = new GzipWriter(compressed, CompressionLevel.Optimal, true))
{
try { compressor.Read(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(NotSupportedException)); }
compressor.Write(s_sampledata, 0, s_sampledata.Length);
compressor.Flush();
}
// Check the constructor for ArgumentNullException while we're here
try { using (GzipReader decompressor = new GzipReader(null, false)) { }; Assert.Fail("Constructor should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentNullException)); }
// Create a decompressor to test some of the error cases
using (GzipReader decompressor = new GzipReader(compressed, true))
{
// Send in some bum arguments to Read() to check they are caught
try { decompressor.Read(null, 0, 0); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentNullException)); }
try { decompressor.Read(buffer, -1, 0); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentOutOfRangeException)); }
try { decompressor.Read(buffer, 0, -1); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentOutOfRangeException)); }
try { decompressor.Read(buffer, 0, buffer.Length + 1024); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ArgumentException)); }
// Attempting to read from the end of the compressed stream should throw an InvalidDataException
try { decompressor.Read(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(InvalidDataException)); }
// Attempting to read from the middle of the compressed stream should throw a GzipException
compressed.Position = compressed.Position / 2;
try { decompressor.Read(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(GzipException)); }
// The decompression stream is trashed at this point since the input buffer was filled
// with data from the middle. Thought about a special case handler for that, but it's
// a fringe case. Verify that the stream is indeed trashed ...
compressed.Position = 0;
try { decompressor.Read(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(GzipException)); }
}
// Create a new decompressor against the same stream and make sure it doesn't throw
using (GzipReader decompressor = new GzipReader(compressed, true))
{
// Reading zero bytes should not throw an exception
decompressor.Read(buffer, 0, 0);
while (decompressor.Read(buffer, 0, 8192) != 0)
{
}
}
}
}
public void Gzip_WriterDispose()
{
byte[] buffer = new byte[8192]; // 8KiB data buffer
// Create a dummy stream and immediately dispose of it
GzipWriter stream = new GzipWriter(new MemoryStream(s_sampledata), CompressionLevel.Optimal);
stream.Dispose();
// Test double dispose
stream.Dispose();
// All properties and methods should throw an ObjectDisposedException
try { var bs = stream.BaseStream; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { var b = stream.CanRead; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { var b = stream.CanSeek; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { var b = stream.CanWrite; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.Flush(); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { var l = stream.Length; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { var l = stream.Position; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.Position = 12345L; Assert.Fail("Property access should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.Read(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.Seek(0, SeekOrigin.Current); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.SetLength(12345L); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.Write(buffer); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
try { stream.Write(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
// Ensure that an underlying stream is disposed of properly if leaveopen is not set
MemoryStream ms = new MemoryStream(s_sampledata);
using (GzipWriter compressor = new GzipWriter(ms, CompressionLevel.Fastest)) { }
try { ms.Write(buffer, 0, 8192); Assert.Fail("Method call should have thrown an exception"); }
catch (Exception ex) { Assert.IsInstanceOfType(ex, typeof(ObjectDisposedException)); }
// Ensure that an underlying stream is not disposed of if leaveopen is set
ms = new MemoryStream(s_sampledata);
using (GzipWriter compressor = new GzipWriter(ms, CompressionLevel.Fastest, true)) { }
ms.Write(buffer, 0, 8192);
ms.Dispose();
}