LZH in Byte Array Decompress in .NET? - archive

Question

An LZH archive is embedded within a file. The file was read into a byte[], and the LZH part is identified as a smaller byte[].
How can the embedded LZH bytes be decompressed into another byte[] using .NET Framework 4.6 (C#)? I have only see http://www.infoq.com/news/2008/06/7-Zip-from-.NET which doesn't exactly do what I need.
Thanks.

Answer 1

the code snippet that follows is taken from the sample program from this article
http://www.codeproject.com/Articles/27148/C-NET-Interface-for-Zip-Archive-DLLs
There are no significant changes: instead of reading and writing files, it reads and write byte arrays. Changes are marked by comments
Run with sevenzip.exe e "C:\temp\gwo0.11-sample-win32.lzh" 3 for example
https://dl.dropboxusercontent.com/u/71459360/7z.zip
using System;
using System.Collections.Generic;
using System.Text;
using Nomad.Archive.SevenZip;
using System.IO;
using System.Runtime.InteropServices;
using System.Reflection;
namespace SevenZip
{
class Program
{
private static void ShowHelp()
{
Console.WriteLine("SevenZip");
Console.WriteLine("SevenZip l {ArchiveName}");
Console.WriteLine("SevenZip e {ArchiveName} {FileNumber}");
}
static void Main(string[] args)
{
if (args.Length < 2)
{
ShowHelp();
return;
}
try
{
string ArchiveName;
uint FileNumber = 0xFFFFFFFF;
bool Extract;
switch (args[0])
{
case "l":
ArchiveName = args[1];
Extract = false;
break;
case "e":
ArchiveName = args[1];
Extract = true;
if ((args.Length < 3) || !uint.TryParse(args[2], out FileNumber))
{
ShowHelp();
return;
}
break;
default:
ShowHelp();
return;
}
using (SevenZipFormat Format = new SevenZipFormat(Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), "7z.dll")))
{
IInArchive Archive = Format.CreateInArchive(SevenZipFormat.GetClassIdFromKnownFormat(KnownSevenZipFormat.Lzh));
if (Archive == null)
{
ShowHelp();
return;
}
try
{
//the byte array is provided by you. here it's coming from a file
byte[] data;
using (var stream = File.OpenRead(ArchiveName))
{
data = new byte[stream.Length];
stream.Read(data, 0, data.Length);
}
using (InStreamWrapper ArchiveStream = new InStreamWrapper(new MemoryStream(data))) //modified here
{
ulong CheckPos = 32 * 1024;
if (Archive.Open(ArchiveStream, ref CheckPos, null) != 0)
ShowHelp();
Console.Write("Archive: ");
Console.WriteLine(ArchiveName);
if (Extract)
{
PropVariant Name = new PropVariant();
Archive.GetProperty(FileNumber, ItemPropId.kpidPath, ref Name);
string FileName = (string) Name.GetObject();
Console.Write("Extracting: ");
Console.Write(FileName);
Console.Write(' ');
MemoryStream ms = new MemoryStream();
Archive.Extract(new uint[] { FileNumber }, 1, 0, new ArchiveMemoryCallback(FileNumber, ms)); //modified here
byte[] output = ms.ToArray(); //here you have the output byte array
output.ToString();
}
else
{
Console.WriteLine("List:");
uint Count = Archive.GetNumberOfItems();
for (uint I = 0; I < Count; I++)
{
PropVariant Name = new PropVariant();
Archive.GetProperty(I, ItemPropId.kpidPath, ref Name);
Console.Write(I);
Console.Write(' ');
Console.WriteLine(Name.GetObject());
}
}
}
}
finally
{
Marshal.ReleaseComObject(Archive);
}
}
}
catch (Exception e)
{
Console.Write("Error: ");
Console.WriteLine(e.Message);
}
}
}
class ArchiveCallback : IArchiveExtractCallback
{
private uint FileNumber;
private string FileName;
private OutStreamWrapper FileStream;
public ArchiveCallback(uint fileNumber, string fileName)
{
this.FileNumber = fileNumber;
this.FileName = fileName;
}
#region IArchiveExtractCallback Members
public void SetTotal(ulong total)
{
}
public void SetCompleted(ref ulong completeValue)
{
}
public int GetStream(uint index, out ISequentialOutStream outStream, AskMode askExtractMode)
{
if ((index == FileNumber) && (askExtractMode == AskMode.kExtract))
{
string FileDir = Path.GetDirectoryName(FileName);
if (!string.IsNullOrEmpty(FileDir))
Directory.CreateDirectory(FileDir);
FileStream = new OutStreamWrapper(File.Create(FileName));
outStream = FileStream;
}
else
outStream = null;
return 0;
}
public void PrepareOperation(AskMode askExtractMode)
{
}
public void SetOperationResult(OperationResult resultEOperationResult)
{
FileStream.Dispose();
Console.WriteLine(resultEOperationResult);
}
#endregion
}
//new
class ArchiveMemoryCallback : IArchiveExtractCallback
{
private uint FileNumber;
private Stream stream;
private OutStreamWrapper FileStream;
public ArchiveMemoryCallback(uint fileNumber, Stream stream)
{
this.FileNumber = fileNumber;
this.stream = stream;
}
#region IArchiveExtractCallback Members
public void SetTotal(ulong total)
{
}
public void SetCompleted(ref ulong completeValue)
{
}
public int GetStream(uint index, out ISequentialOutStream outStream, AskMode askExtractMode)
{
if ((index == FileNumber) && (askExtractMode == AskMode.kExtract))
{
FileStream = new OutStreamWrapper(stream);
outStream = FileStream;
}
else
outStream = null;
return 0;
}
public void PrepareOperation(AskMode askExtractMode)
{
}
public void SetOperationResult(OperationResult resultEOperationResult)
{
FileStream.Dispose();
Console.WriteLine(resultEOperationResult);
}
#endregion
}
}