using 7zip sdk to compress a file, but the archive file is not as original and can not decompress using unrar

问题

I am using 7zip sdk (http://www.7-zip.org/sdk.html) to compress a file.

it works fine using this wrapper:

public void EncodeSingleFile(FileStream inStream, FileStream outStream)   {
     bool eos = false;
     Int32 dictionary = 1 << 21;
     Int32 posStateBits = 2;
     Int32 litContextBits = 3; // for normal files
     // UInt32 litContextBits = 0; // for 32-bit data
     Int32 litPosBits = 0;
     // UInt32 litPosBits = 2; // for 32-bit data
     Int32 algorithm = 2;
     Int32 numFastBytes = 128;
     string mf = "bt4";

     propIDs = new CoderPropID[]
        {
           CoderPropID.DictionarySize,
           CoderPropID.PosStateBits,
           CoderPropID.LitContextBits,
           CoderPropID.LitPosBits,
           CoderPropID.Algorithm,
           CoderPropID.NumFastBytes,
           CoderPropID.MatchFinder,
           CoderPropID.EndMarker
        };
     properties = new object[]
        {
           dictionary,
           posStateBits,
           litContextBits,
           litPosBits,
           algorithm,
           numFastBytes,
           mf,
           eos
        };

     Encoder encoder = new Encoder();
     encoder.SetCoderProperties(propIDs, properties);
     encoder.WriteCoderProperties(outStream);
     Int64 fileSize = inStream.Length;
     for (int i = 0; i < 8; i++)
     {
        outStream.WriteByte((Byte) (fileSize >> (8*i)));
     }
     encoder.Code(inStream, outStream, -1, -1, null);

}

However, I have got a problem:

I can only decompress it using 7zip shell installed from 7-zip.org, can not decompress with unrar. is that possible if I set some parameters and it will work with unrar as well?

If I open the file in 7zip and check the properties, I got:

Name: abc.pdb
Size: 1 809 920
Packed Size: 249 305
Method: LZMA:21
Type: lzma

回答1:

There is an example on CodeProject of someone creating a C# interface for 7z using the SDK. He also mentions it is now possible to use COM against the DLL's, but I don't know how that works.

Check out C# (.NET) Interface for 7-Zip Archive DLLs on The Code Project.

回答2:

If you are looking to create a RAR archive, you may be out of luck, as it is closed-source. You can probably use external libraries, but the compression algorithm is proprietary.

From the RAR Wiki Page:

RAR files may be created only with commercial software WinRAR, RAR, and software that has permission from the licensor Alexander Roshal

I would recommend investigating one of the many unencumbered alternatives.

来源：https://stackoverflow.com/questions/8340636/using-7zip-sdk-to-compress-a-file-but-the-archive-file-is-not-as-original-and-c

标签

7zip