question: void compress ( int page , byte [ ] old ) { byte [ ] [ ] array = data ; if ( page >= array . length ) { return ; } byte [ ] d = array [ page ] ; if ( d != old ) { return ; } synchronized ( LZF ) { int len = LZF . compress ( d , BLOCK_SIZE , BUFFER , 0 ) ; if ( len <= BLOCK_SIZE ) { d = new byte [ len ] ; System . arraycopy ( BUFFER , 0 , d , 0 , len ) ; byte [ ] o = array [ page ] ; if ( o != old ) { return ; } array [ page ] = d ; } } }
target:  Compress the data in a byte array.