Android class to decompress .tar file created using gzip

A file on a server is created using gzip to create a compressed tar file. That file is then downloaded to the SDCard on any android device running Android 2.3 (greater including 4.1 aks Ice Cream Sandwich). Once the file is on the SDCard it must be decompressed and the archived directories/files expanded into a specified target directory. Example: File tarFile = new File(tarFileLocation); //tarFileLocation : location on SDCard where the .tar file is File expandTo = new File(expandToDirectory); //expandToDirectory: directory on SDCard where to expand the .tar file try { [login to view URL](tarFile,expandTo); } catch : The class can NOT use any libraries, code, software patents, etc that have any fee, purchase, royalties associated. The .tar files may be quite large (greater than 10mg), so the expansion should run on a background task or thread.