由于需要，想要找到一个以Objc所写的，可以解压多种压缩格式的框架。
起初试过ZipArchive, SSZipArchive，都不能满足要求，都只是单一或几种格式，特别是我需要解压Mac平台上的cpgz压缩格式。然后我发现它unarchiver.app。
mac平台上的一个解压app，它是一个open source project[Github]。它是以一个叫XADMaster的框架操作多种格式的解压。
This is a library providing an interface for unarchiving all possible types of file or disk archives. It is NOT an archiver GUI or anything like that. This system does the COMPLETE unarchiving stuff with internal routines, NOT calling shell programs or using other programs to do the work! It is comparable toxfdmaster.libraysystem providing same features for crunched files and programs.
