public static void validateUTF8()

in odps-sdk/odps-sdk-commons/src/main/java/com/aliyun/odps/io/Text.java [507:570]
58 lines of code
23 McCabe index (conditional complexity)

  public static void validateUTF8(byte[] utf8, int start, int len)
      throws MalformedInputException {
    int count = start;
    int leadByte = 0;
    int length = 0;
    int state = LEAD_BYTE;
    while (count < start + len) {
      int aByte = ((int) utf8[count] & 0xFF);

      switch (state) {
      case LEAD_BYTE:
        leadByte = aByte;
        length = bytesFromUTF8[aByte];

        switch (length) {
        case 0: // check for ASCII
          if (leadByte > 0x7F)
            throw new MalformedInputException(count);
          break;
        case 1:
          if (leadByte < 0xC2 || leadByte > 0xDF)
            throw new MalformedInputException(count);
          state = TRAIL_BYTE_1;
          break;
        case 2:
          if (leadByte < 0xE0 || leadByte > 0xEF)
            throw new MalformedInputException(count);
          state = TRAIL_BYTE_1;
          break;
        case 3:
          if (leadByte < 0xF0 || leadByte > 0xF4)
            throw new MalformedInputException(count);
          state = TRAIL_BYTE_1;
          break;
        default:
          // too long! Longest valid UTF-8 is 4 bytes (lead + three)
          // or if < 0 we got a trail byte in the lead byte position
          throw new MalformedInputException(count);
        } // switch (length)
        break;

      case TRAIL_BYTE_1:
        if (leadByte == 0xF0 && aByte < 0x90)
          throw new MalformedInputException(count);
        if (leadByte == 0xF4 && aByte > 0x8F)
          throw new MalformedInputException(count);
        if (leadByte == 0xE0 && aByte < 0xA0)
          throw new MalformedInputException(count);
        if (leadByte == 0xED && aByte > 0x9F)
          throw new MalformedInputException(count);
        // falls through to regular trail-byte test!!
      case TRAIL_BYTE:
        if (aByte < 0x80 || aByte > 0xBF)
          throw new MalformedInputException(count);
        if (--length == 0) {
          state = LEAD_BYTE;
        } else {
          state = TRAIL_BYTE;
        }
        break;
      } // switch (state)
      count++;
    }
  }