question: private boolean yy_refill ( ) throws java . io . IOException { if ( yy_startRead > 0 ) { System . arraycopy ( yy_buffer , yy_startRead , yy_buffer , 0 , yy_endRead - yy_startRead ) ; yy_endRead -= yy_startRead ; yy_currentPos -= yy_startRead ; yy_markedPos -= yy_startRead ; yy_pushbackPos -= yy_startRead ; yy_startRead = 0 ; } if ( yy_currentPos >= yy_buffer . length ) { char newBuffer [ ] = new char [ yy_currentPos * 2 ] ; System . arraycopy ( yy_buffer , 0 , newBuffer , 0 , yy_buffer . length ) ; yy_buffer = newBuffer ; } int numRead = yy_reader . read ( yy_buffer , yy_endRead , yy_buffer . length - yy_endRead ) ; if ( numRead < 0 ) { return true ; } else { yy_endRead += numRead ; return false ; } }
target:  Refills the input buffer.