Best .NET Framework compression class?

Question

Yes, I know GZipStream or DeflateStream is the common ones in .NET Framework which handle compression/decompression.

I wish to have compress/decompress functions in my program, but

1. I wish a .NET Framework C# one, not a 3rd party open source. I can't use because of those copyright restrictions in my program.

2. GZipStream and DeflateStream are not so good. for eg, GZipStream compress a file to 480KB while 7Zip compress the same file to the size of 57KB.

Does Microsoft have other good compression methods???

Thanks

Answer 1

GZipStream and DeflateStream are specifically intended for compressed streams , not general compression of files for storage.

Other than those classes, compression is not built into .NET. If you want high-quality compression you will have to go to a third party library. Check out http://www.7-zip.org/sdk.html for an open-source 7zip library.

Answer 2

There is a managed wrapper for 7zip. The license is LGPL so you can use it in closed source projects. I do not know if this fits your license requirements as you did not state them.

http://sevenzipsharp.codeplex.com/

Answer 3

我没有关于压缩率的任何统计数据，但我多年来一直在使用SharpZipLib库并取得了很大的成功。

Answer 4

you can also use the open source ZLib ( http://www.zlib.net/ ) with PInvoke, or use a wrapper for it (I've used zlib.net - http://www.componentace.com/zlib_.NET.htm - but I believe it had some bugs). it's less convenient than managed libraries, but more efficient than DeflateStream/GZipStream (which are the same except for an extra CRC in GZipStream).

Answer 5

Well, I try to compress like recursive data, is funny. Check my example:

private byte[] CompressWithLevels(byte[] data)
{
    using(MemoryStream ms = new MemoryStream())
    {
        using(GZipStream gz = new GZipStream(ms, CompressionMode.Compress))
        {
            gz.Write(data, 0, data.Length);
            return ms.ToArray();
        }
    }
}

Now, I try to Compress a file too big, for example:

string path = @"c:\test.bin";
byte[] buffer = File.ReadAllBytes(path);
byte[] level1 = CompressWithLevels(buffer);
byte[] level2 = CompressWithLevels(level1);

Check the size of buffer, level1 and level2.
buffer size is 77683, level1 = 57354 and level2 = 8202...

buffer is 100%, then:
57354 is 73,83%
8202 is 10,55%
so funny.