How to unzip a zip folder using php code

I want to unzip directorires.

That means i have a zipped directory name with xxx.zip.In manuall i right clicked on the zipped directory and do extract folder,then i got an unzipped dirtectory with name xxx and also in this directory have a same directory xxx.In the subfolder will contained the files.

That means, xxx->xxx->files this is the heirarchi of unzipped folder.

So in my site i want to unzipp a directory using php code.

How can i do this? I need only xxx->files not xxx->xxx->files structure.

How can i do this?