public SetDeflateParams ( CompressionLevel level, CompressionStrategy strategy ) : int | ||
level | CompressionLevel | the level of compression to use. |
strategy | CompressionStrategy | the strategy to use for compression. |
return | int |
private void Run() { int rc; int j; int bufferSize = 40000; byte[] compressedBytes = new byte[bufferSize]; byte[] bufferToCompress= new byte[bufferSize]; byte[] decompressedBytes = new byte[bufferSize]; ZlibCodec compressingStream= new ZlibCodec(); rc = compressingStream.InitializeDeflate(CompressionLevel.BestSpeed); CheckForError(compressingStream, rc, "InitializeDeflate"); compressingStream.OutputBuffer = compressedBytes; compressingStream.NextOut = 0; compressingStream.AvailableBytesOut = compressedBytes.Length; // At this point, bufferToCompress is all zeroes, so it should compress // very well: compressingStream.InputBuffer = bufferToCompress; compressingStream.AvailableBytesIn = bufferToCompress.Length; rc = compressingStream.Deflate(FlushType.None); CheckForError(compressingStream, rc, "deflate"); if (compressingStream.AvailableBytesIn != 0) { System.Console.Out.WriteLine("deflate not greedy"); System.Environment.Exit(1); } Console.WriteLine("Stage 1: uncompressed bytes in so far: {0,6}", compressingStream.TotalBytesIn); Console.WriteLine(" compressed bytes out so far: {0,6}", compressingStream.TotalBytesOut); // Feed in already compressed data and switch to no compression: compressingStream.SetDeflateParams(CompressionLevel.None, CompressionStrategy.Default); compressingStream.InputBuffer = compressedBytes; compressingStream.NextIn = 0; compressingStream.AvailableBytesIn = bufferSize / 2; // why? - for fun rc = compressingStream.Deflate(FlushType.None); CheckForError(compressingStream, rc, "Deflate"); Console.WriteLine("Stage 2: uncompressed bytes in so far: {0,6}", compressingStream.TotalBytesIn); Console.WriteLine(" compressed bytes out so far: {0,6}", compressingStream.TotalBytesOut); // Insert data into bufferToCompress, and Switch back to compressing mode: System.Random rnd = new Random(); for (int i = 0; i < bufferToCompress.Length / 1000; i++) { byte b = (byte) rnd.Next(); int n = 500 + rnd.Next(500); for (j = 0; j < n; j++) bufferToCompress[j + i] = b; i += j-1; } compressingStream.SetDeflateParams(CompressionLevel.BestCompression, CompressionStrategy.Filtered); compressingStream.InputBuffer = bufferToCompress; compressingStream.NextIn = 0; compressingStream.AvailableBytesIn = bufferToCompress.Length; rc = compressingStream.Deflate(FlushType.None); CheckForError(compressingStream, rc, "Deflate"); Console.WriteLine("Stage 3: uncompressed bytes in so far: {0,6}", compressingStream.TotalBytesIn); Console.WriteLine(" compressed bytes out so far: {0,6}", compressingStream.TotalBytesOut); rc = compressingStream.Deflate(FlushType.Finish); if (rc != ZlibConstants.Z_STREAM_END) { Console.WriteLine("deflate reported {0}, should report Z_STREAM_END", rc); Environment.Exit(1); } rc = compressingStream.EndDeflate(); CheckForError(compressingStream, rc, "EndDeflate"); Console.WriteLine("Stage 4: uncompressed bytes in (final): {0,6}", compressingStream.TotalBytesIn); Console.WriteLine(" compressed bytes out (final): {0,6}", compressingStream.TotalBytesOut); ZlibCodec decompressingStream = new ZlibCodec(CompressionMode.Decompress); decompressingStream.InputBuffer = compressedBytes; decompressingStream.NextIn = 0; decompressingStream.AvailableBytesIn = bufferSize; // upon inflating, we overwrite the decompressedBytes buffer repeatedly while (true) { decompressingStream.OutputBuffer = decompressedBytes; decompressingStream.NextOut = 0; decompressingStream.AvailableBytesOut = decompressedBytes.Length; rc = decompressingStream.Inflate(FlushType.None); if (rc == ZlibConstants.Z_STREAM_END) break; CheckForError(decompressingStream, rc, "inflate large"); } rc = decompressingStream.EndInflate(); CheckForError(decompressingStream, rc, "EndInflate"); if (decompressingStream.TotalBytesOut != 2 * decompressedBytes.Length + bufferSize / 2) { System.Console.WriteLine("bad large inflate: " + decompressingStream.TotalBytesOut); System.Environment.Exit(1); } for (j = 0; j < decompressedBytes.Length; j++) if (decompressedBytes[j] == 0) break; Console.WriteLine("compressed length: {0}", compressingStream.TotalBytesOut); Console.WriteLine("decompressed length (expected): {0}", 2 * decompressedBytes.Length + bufferSize / 2); Console.WriteLine("decompressed length (actual) : {0}", decompressingStream.TotalBytesOut); }
public void Zlib_Codec_TestLargeDeflateInflate() { int rc; int j; int bufferSize = 80000; byte[] compressedBytes = new byte[bufferSize]; byte[] workBuffer = new byte[bufferSize / 4]; ZlibCodec compressingStream = new ZlibCodec(); rc = compressingStream.InitializeDeflate(CompressionLevel.Level1); Assert.AreEqual<int>(ZlibConstants.Z_OK, rc, String.Format("at InitializeDeflate() [{0}]", compressingStream.Message)); compressingStream.OutputBuffer = compressedBytes; compressingStream.AvailableBytesOut = compressedBytes.Length; compressingStream.NextOut = 0; System.Random rnd = new Random(); for (int k = 0; k < 4; k++) { switch (k) { case 0: // At this point, workBuffer is all zeroes, so it should compress very well. break; case 1: // switch to no compression, keep same workBuffer (all zeroes): compressingStream.SetDeflateParams(CompressionLevel.None, CompressionStrategy.Default); break; case 2: // Insert data into workBuffer, and switch back to compressing mode. // we'll use lengths of the same random byte: for (int i = 0; i < workBuffer.Length / 1000; i++) { byte b = (byte)rnd.Next(); int n = 500 + rnd.Next(500); for (j = 0; j < n; j++) workBuffer[j + i] = b; i += j - 1; } compressingStream.SetDeflateParams(CompressionLevel.BestCompression, CompressionStrategy.Filtered); break; case 3: // insert totally random data into the workBuffer rnd.NextBytes(workBuffer); break; } compressingStream.InputBuffer = workBuffer; compressingStream.NextIn = 0; compressingStream.AvailableBytesIn = workBuffer.Length; rc = compressingStream.Deflate(FlushType.None); Assert.AreEqual<int>(ZlibConstants.Z_OK, rc, String.Format("at Deflate({0}) [{1}]", k, compressingStream.Message)); if (k == 0) Assert.AreEqual<int>(0, compressingStream.AvailableBytesIn, "Deflate should be greedy."); TestContext.WriteLine("Stage {0}: uncompressed/compresssed bytes so far: ({1,6}/{2,6})", k, compressingStream.TotalBytesIn, compressingStream.TotalBytesOut); } rc = compressingStream.Deflate(FlushType.Finish); Assert.AreEqual<int>(ZlibConstants.Z_STREAM_END, rc, String.Format("at Deflate() [{0}]", compressingStream.Message)); rc = compressingStream.EndDeflate(); Assert.AreEqual<int>(ZlibConstants.Z_OK, rc, String.Format("at EndDeflate() [{0}]", compressingStream.Message)); TestContext.WriteLine("Final: uncompressed/compressed bytes: ({0,6},{1,6})", compressingStream.TotalBytesIn, compressingStream.TotalBytesOut); ZlibCodec decompressingStream = new ZlibCodec(CompressionMode.Decompress); decompressingStream.InputBuffer = compressedBytes; decompressingStream.NextIn = 0; decompressingStream.AvailableBytesIn = bufferSize; // upon inflating, we overwrite the decompressedBytes buffer repeatedly int nCycles = 0; while (true) { decompressingStream.OutputBuffer = workBuffer; decompressingStream.NextOut = 0; decompressingStream.AvailableBytesOut = workBuffer.Length; rc = decompressingStream.Inflate(FlushType.None); nCycles++; if (rc == ZlibConstants.Z_STREAM_END) break; Assert.AreEqual<int>(ZlibConstants.Z_OK, rc, String.Format("at Inflate() [{0}] TotalBytesOut={1}", decompressingStream.Message, decompressingStream.TotalBytesOut)); } rc = decompressingStream.EndInflate(); Assert.AreEqual<int>(ZlibConstants.Z_OK, rc, String.Format("at EndInflate() [{0}]", decompressingStream.Message)); Assert.AreEqual<int>(4 * workBuffer.Length, (int)decompressingStream.TotalBytesOut); TestContext.WriteLine("compressed length: {0}", compressingStream.TotalBytesOut); TestContext.WriteLine("decompressed length (expected): {0}", 4 * workBuffer.Length); TestContext.WriteLine("decompressed length (actual) : {0}", decompressingStream.TotalBytesOut); TestContext.WriteLine("decompression cycles: {0}", nCycles); }