question: protected void fill ( ) throws IOException { checkClosed ( ) ; if ( nativeEndBufSize > 0 ) { ZipFile . RAFStream is = ( ZipFile . RAFStream ) in ; len = is . fill ( inf , nativeEndBufSize ) ; } else { if ( ( len = in . read ( buf ) ) > 0 ) { inf . setInput ( buf , 0 , len ) ; } } }
target:  Fills the input buffer with data to be decompressed.