Pfthb

I'm trying to read a series of gzip files using the code below.

What I end up with is a file that is only a fraction of the total file. Interestingly enough the text file output is almost perfectly truncated at a line break.

public static string UnzipFile(string filename)

 FileInfo fi = new FileInfo(filename);
 Console.WriteLine($" - - - - - UnzipFile filename fi.Length - - - - - ");
 string newFileName = filename.Substring(0, filename.Length - 4);

 try
 
 byte buffer = new byte[4096]; // read in chunks of 4KB
 using (FileStream fs2 = new FileStream(newFileName, FileMode.CreateNew))
 
 using (FileStream fs = new FileStream(filename, FileMode.Open))
 
 using (GZipStream zipStream = new GZipStream(fs, CompressionMode.Decompress))
 
 zipStream.BufferSize = 1024;
 int bytesRead;
 while((bytesRead = zipStream.Read(buffer, 0, buffer.Length)) > 0)
 
 Console.WriteLine($" bytesRead ");
 fs2.Write(buffer, 0, bytesRead);
 fs2.Flush(true);
 
 
 
 
 FileInfo fi2 = new FileInfo(newFileName);
 Console.WriteLine($" - - - - newFileName fi2.Length");
 
 catch (Exception e)
 
 Console.WriteLine($" - - - - - EXCEPTION e.Message e.StackTrace");
 
 return newFileName;
 

Here is partial output from running the code:

UnzipFile : 177686_2018-10-18_0#289.json.gz 34975
4096
4096
 855
 177686_2018-10-18_0#289.json 9047

So it looks like a file of size 34975 bytes when compressed ends up decompressing only 9047 bytes. If I use gunzip on a mac to expand the file I get a file 223344 bytes in size.

Where have I gone wrong?

edit: Additional data

In case it helps, I get this when using GZip.Decompress

Bad CRC32 in GZIP trailer. (actual(7C64AEAA)!=expected(F641B726)) at Ionic.Zlib.ZlibBaseStream.finish()

Additional data when examining the position of the FileStream

fs pos: 2093 fs len: 33930