public WorkItem(int size, Ionic.Zlib.CompressionLevel compressLevel, CompressionStrategy strategy)
{
buffer= new byte[size];
// alloc 5 bytes overhead for every block (margin of safety= 2)
int n = size + ((size / 32768)+1) * 5 * 2;
compressed= new byte[n];
status = (int)Status.None;
compressor = new ZlibCodec();
compressor.InitializeDeflate(compressLevel, false);
compressor.OutputBuffer = compressed;
compressor.InputBuffer = buffer;
}
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);
}
