question: private boolean zzRefill ( ) throws java . io . IOException { if ( zzStartRead > 0 ) { System . arraycopy ( zzBuffer , zzStartRead , zzBuffer , 0 , zzEndRead - zzStartRead ) ; zzEndRead -= zzStartRead ; zzCurrentPos -= zzStartRead ; zzMarkedPos -= zzStartRead ; zzPushbackPos -= zzStartRead ; zzStartRead = 0 ; } if ( zzCurrentPos >= zzBuffer . length ) { char newBuffer [ ] = new char [ zzCurrentPos * 2 ] ; System . arraycopy ( zzBuffer , 0 , newBuffer , 0 , zzBuffer . length ) ; zzBuffer = newBuffer ; } int numRead = zzReader . read ( zzBuffer , zzEndRead , zzBuffer . length - zzEndRead ) ; if ( numRead < 0 ) { return true ; } else { zzEndRead += numRead ; return false ; } }
target:  Refills the input buffer.