question: private boolean zzRefill ( ) throws java . io . IOException { if ( zzStartRead > 0 ) { zzEndRead += zzFinalHighSurrogate ; zzFinalHighSurrogate = 0 ; System . arraycopy ( zzBuffer , zzStartRead , zzBuffer , 0 , zzEndRead - zzStartRead ) ; zzEndRead -= zzStartRead ; zzCurrentPos -= zzStartRead ; zzMarkedPos -= zzStartRead ; zzStartRead = 0 ; } int requested = zzBuffer . length - zzEndRead - zzFinalHighSurrogate ; int totalRead = 0 ; while ( totalRead < requested ) { int numRead = zzReader . read ( zzBuffer , zzEndRead + totalRead , requested - totalRead ) ; if ( numRead == - 1 ) { break ; } totalRead += numRead ; } if ( totalRead > 0 ) { zzEndRead += totalRead ; if ( totalRead == requested ) { if ( Character . isHighSurrogate ( zzBuffer [ zzEndRead - 1 ] ) ) { -- zzEndRead ; zzFinalHighSurrogate = 1 ; if ( totalRead == 1 ) { return true ; } } } return false ; } return true ; }
target:  Refills the input buffer.