Reading compressed textfile on-the-fly

Reading .gz textfile line after line

This class open a .gz file (usual format of compressed log files) and will return a line at each call of .NextLine()

There is no memory usage for temporary decompression, very useful for large file.

Imports System.IO

Class logread_gz

  Private ptr As FileStream
  Private UnGZPtr As Compression.GZipStream
  Private line_ptr As StreamReader
  Private spath As String 

  Sub New(full_filename As String)
    spath = full_filename
  End Sub   

  Sub Open()
     Me.ptr = File.OpenRead(spath)
     Me.UnGZPtr = New Compression.GZipStream(ptr, Compression.CompressionMode.Decompress)
     Me.line_ptr = New StreamReader(UnGZPtr)
  End Sub()

  Function NextLine() As String
    'will return Nothing if EOF
    Return Me.line_ptr.ReadLine()
  End Function

  Sub Close()
    Me.line_ptr.Close()
    Me.line_ptr.Dispose()
    Me.UnGZPtr.Close()
    Me.UnGZPtr.Dispose()
    Me.ptr.Close()
    Me.ptr.Dispose()
  End Sub

End Class

Note : there is no failsafe, for readbility purpose.