code: static int adjustConfidence(int codeUnit, int confidence) {
          if (codeUnit == 0) {
              confidence -= 10;
          } else if ((codeUnit >= 0x20 && codeUnit <= 0xff) || codeUnit == 0x0a) {
              confidence += 10;
          }
          if (confidence < 0) {
              confidence = 0;
          } else if (confidence > 100) {
              confidence = 100;
          }
          return confidence;
      }
docs: NULs should be rare in actual text.