question: private static int determineConsecutiveBinaryCount ( String msg , int startpos , Charset encoding ) throws WriterException { final CharsetEncoder encoder = encoding . newEncoder ( ) ; int len = msg . length ( ) ; int idx = startpos ; while ( idx < len ) { char ch = msg . charAt ( idx ) ; int numericCount = 0 ; while ( numericCount < 13 && isDigit ( ch ) ) { numericCount ++ ; int i = idx + numericCount ; if ( i >= len ) { break ; } ch = msg . charAt ( i ) ; } if ( numericCount >= 13 ) { return idx - startpos ; } ch = msg . charAt ( idx ) ; if ( ! encoder . canEncode ( ch ) ) { throw new WriterException ( "Non-encodable character detected: " + ch + " (Unicode: " + ( int ) ch + ')' ) ; } idx ++ ; } return idx - startpos ; }
target:  Determines the number of consecutive characters that are encodable using binary compaction.