code: private int diff_cleanupSemanticScore(String one, String two) {
      if (one.length() == 0 || two.length() == 0) {
        // Edges are the best.
        return 6;
      }
  
      // Each port of this function behaves slightly differently due to
      // subtle differences in each language's definition of things like
      // 'whitespace'.  Since this function's purpose is largely cosmetic,
      // the choice has been made to use each language's native features
      // rather than force total conformity.
      char char1 = one.charAt(one.length() - 1);
      char char2 = two.charAt(0);
      boolean nonAlphaNumeric1 = !Character.isLetterOrDigit(char1);
      boolean nonAlphaNumeric2 = !Character.isLetterOrDigit(char2);
      boolean whitespace1 = nonAlphaNumeric1 && Character.isWhitespace(char1);
      boolean whitespace2 = nonAlphaNumeric2 && Character.isWhitespace(char2);
      boolean lineBreak1 = whitespace1
          && Character.getType(char1) == Character.CONTROL;
      boolean lineBreak2 = whitespace2
          && Character.getType(char2) == Character.CONTROL;
      boolean blankLine1 = lineBreak1 && BLANKLINEEND.matcher(one).find();
      boolean blankLine2 = lineBreak2 && BLANKLINESTART.matcher(two).find();
  
      if (blankLine1 || blankLine2) {
        // Five points for blank lines.
        return 5;
      } else if (lineBreak1 || lineBreak2) {
        // Four points for line breaks.
        return 4;
      } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) {
        // Three points for end of sentences.
        return 3;
      } else if (whitespace1 || whitespace2) {
        // Two points for whitespace.
        return 2;
      } else if (nonAlphaNumeric1 || nonAlphaNumeric2) {
        // One point for non-alphanumeric.
        return 1;
      }
      return 0;
    }
docs: Given two strings, compute a score representing whether the internal
  boundary falls on logical boundaries.
  Scores range from 6 (best) to 0 (worst).
  @param one First string.
  @param two Second string.
  @return The score.