How to decompress .bz2 file in C#?

Question

I am developing wpf application. I am using sharpziplib to compress and decompress files. I am easily decompress the .zip files using following code

public static void UnZip(string SrcFile, string DstFile, string safeFileName, int bufferSize)
        {
            //ICSharpCode.SharpZipLib.Zip.UseZip64.Off;

            FileStream fileStreamIn = new FileStream(SrcFile, FileMode.Open, FileAccess.Read);
            ZipInputStream zipInStream = new ZipInputStream(fileStreamIn);


            string rootDirectory = string.Empty;
            if (safeFileName.Contains(".zip"))
            {
                rootDirectory = safeFileName.Replace(".zip", string.Empty);
            }
            else
            {
                rootDirectory = safeFileName;
            }

            Directory.CreateDirectory(App.ApplicationPath + rootDirectory);

            while (true)
            {
                ZipEntry entry = zipInStream.GetNextEntry();

                if (entry == null)
                    break;

                if (entry.Name.Contains("/"))
                {
                    string[] folders = entry.Name.Split('/');

                    string lastElement = folders[folders.Length - 1];
                    var folderList = new List<string>(folders);
                    folderList.RemoveAt(folders.Length - 1);
                    folders = folderList.ToArray();

                    string folderPath = "";
                    foreach (string str in folders)
                    {
                        folderPath = folderPath + "/" + str;
                        if (!Directory.Exists(App.ApplicationPath + rootDirectory + "/" + folderPath))
                        {
                            Directory.CreateDirectory(App.ApplicationPath + rootDirectory + "/" + folderPath);
                        }
                    }

                    if (!string.IsNullOrEmpty(lastElement))
                    {
                        folderPath = folderPath + "/" + lastElement;
                        WriteToFile(DstFile + rootDirectory + @"\" + folderPath, bufferSize, zipInStream, rootDirectory, entry);
                    }

                }
                else
                {
                    WriteToFile(DstFile + rootDirectory + @"\" + entry.Name, bufferSize, zipInStream, rootDirectory, entry);
                }
            }

            zipInStream.Close();           
            fileStreamIn.Close();
        }

        private static void WriteToFile(string DstFile, int bufferSize, ZipInputStream zipInStream, string rootDirectory, ZipEntry entry)
        {
            FileStream fileStreamOut = new FileStream(DstFile, FileMode.OpenOrCreate, FileAccess.Write);
            int size;
            byte[] buffer = new byte[bufferSize];

            do
            {
                size = zipInStream.Read(buffer, 0, buffer.Length);
                fileStreamOut.Write(buffer, 0, size);
            } while (size > 0);

            fileStreamOut.Close();
        }

But the same code is not working with .bz2 files. It is giving error at line

ZipEntry entry = zipInStream.GetNextEntry();

The error is - Wrong Local header signature: 0x26594131. How should I decompress the .bz2 file ? Can you please provide me any code or link through which I can resolve the above issue ?

Answer 1

While you use a ZipInputStream for .zip files, you should use a BZip2InputStream for .bz2 files (and GZipInputStream for .gz files etc.).

Answer 2

Unlike Zip (and RAR and tar), bz2 and gzip are just byte stream compressors. They have no concept of a container format like the aforementioned, and hence why it fails on GetNextEntry. (In other words, bz2 and gzip will only have 1 entry at most).