求CRC校验码的java程序

[java]代码库

public short CRC(byte[] arr, int len) {
  
        int index = 0;
        // Update the CRC for transmitted and received data using
        // the CCITT 16bit algorithm (X^16 + X^12 + X^5 + 1).
        short crc = 0;
          
        while (index < len) {
            crc = (short) ((crc >> 8) | (crc << 8));
            crc ^= arr[index++];
            crc ^= (char) (crc & 0xff) >> 4;
            crc ^= (crc << 8) << 4;
            crc ^= ((crc & 0xff) << 4) << 1;
        }
        return crc;
    }