Android CRC-CCITT(XMODEM)(循环冗余校验)

释放双眼,带上耳机,听听看~!
    开发与服务端SOCKET通讯的过程中遇到 CRC(循环冗余校验)采用 CCITT(XMODEM)模式这里做一下记录,附上查询与计算两种方式,以及16进制与字符串相互转换的方法。
public class AndroidService {
/**
* 模拟服务器  可直接运行
*
*/
static final char TABLE1021[] = { /* CRC1021余式表 */
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108,
0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231,
0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 0x9339,
0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 0x2462,
0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a,
0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, 0x3653,
0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, 0xb75b,
0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4,
0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, 0xc9cc,
0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 0x5af5,
0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd,
0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 0x6ca6,
0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 0xedae,
0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97,
0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, 0xff9f,
0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, 0x9188,
0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080,
0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83b9,
0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 0x02b1,
0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea,
0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 0x34e2,
0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xa7db,
0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3,
0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, 0xd94c,
0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, 0x5844,
0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d,
0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, 0x4a75,
0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 0xfd2e,
0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26,
0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 0xef1f,
0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 0x6e17,
0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0 };
/**
* 将16进制字符串转换为byte[]
* FE0099CF010A01005243FE
*
* @param str
* @return
*/
public static byte[] toBytes(String str) {
if (str == null || str.trim().equals("")) {
return new byte[0];
}
byte[] bytes = new byte[str.length() / 2];
for (int i = 0; i < str.length() / 2; i++) {
String subStr = str.substring(i * 2, i * 2 + 2);
bytes[i] = (byte) Integer.parseInt(subStr, 16);
}
//        Log.e("tag1",BytesHexStrTranslate.bytesToHexFun1(bytes)+"");
//        Log.e("tag1111111", bytes + "");
return bytes;
}
public static int CRC_XModem(byte[] bytes){
int crc = 0x00;          // initial value
int polynomial = 0x1021;
for (int index = 0 ; index< bytes.length; index++) {
byte b = bytes[index];
for (int i = 0; i < 8; i++) {
boolean bit = ((b   >> (7-i) & 1) == 1);
boolean c15 = ((crc >> 15    & 1) == 1);
crc <<= 1;
if (c15 ^ bit) crc ^= polynomial;
}
}
crc &= 0xffff;
System.out.println(crc +"");
return crc;
}
/**
* 数组转换成十六进制字符串
//     * @param byte[]
* @return HexString
*/
public static final String bytesToHexString(byte[] bArray) {
StringBuffer sb = new StringBuffer(bArray.length);
String sTemp;
for (int i = 0; i < bArray.length; i++) {
sTemp = Integer.toHexString(0xFF & bArray[i]);
if (sTemp.length() < 2)
sb.append(0);
sb.append(sTemp.toUpperCase());
}
return sb.toString();
}
public static void main(String args[]) {
byte[] b = new byte[] {
(byte) 0x2C, (byte) 0x00, (byte) 0xFF, (byte) 0xFE,
(byte) 0xFE, (byte) 0x04, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x00 };
//16 进制字符串转byte
b = toBytes("0099CF010A0100");
int a = getCRC1021(b, 7);
System.out.println("查表法:" + a);
String str = Integer.toHexString(a).toUpperCase();
System.out.println("十六进制:" + str);
System.out.println("计算法:" + CRC_XModem(b));
System.out.println("十六进制:"
+ Integer.toHexString(CRC_XModem(b)).toUpperCase());
}
public static char getCRC1021(byte b[], int len) {
char crc = 0;
byte hb = 0;
int j = 0;
int index;
while (len-- != 0) {
hb = (byte) (crc / 256); //以8位二进制数的形式暂存CRC的高8位
index = ((hb ^ b[j]) & 0xff); //求得所查索引下标
crc <<= 8; // 左移8位,相当于CRC的低8位乘以
crc ^= (TABLE1021[index]); // 高8位和当前字节相加后再查表求CRC ,再加上以前的CRC
j++;
}
return (crc);
}
}

转换工具类
public class HexUtils {
/**
* 字符串转换成十六进制字符串
*/
public static String str2HexStr(String str) {
char[] chars = "0123456789ABCDEF".toCharArray();
StringBuilder sb = new StringBuilder("");
byte[] bs = str.getBytes();
int bit;
for (int i = 0; i < bs.length; i++) {
bit = (bs[i] & 0x0f0) >> 4;
sb.append(chars[bit]);
bit = bs[i] & 0x0f;
sb.append(chars[bit]);
}
return sb.toString();
}
//    十六进制字符串转换成为数组方法1:
/**
* 把16进制字符串转换成字节数组
//     * @param hexString
* @return byte[]
*/
public static byte[] hexStringToByte(String hex) {
int len = (hex.length() / 2);
byte[] result = new byte[len];
char[] achar = hex.toCharArray();
for (int i = 0; i < len; i++) {
int pos = i * 2;
result[i] = (byte) (toByte(achar[pos]) << 4 | toByte(achar[pos + 1]));
}
return result;
}
private static int toByte(char c) {
byte b = (byte) "0123456789ABCDEF".indexOf(c);
return b;
}
//    数组转换成十六进制字符串方法1:
/**
* 数组转换成十六进制字符串
//     * @param byte[]
* @return HexString
*/
public static final String bytesToHexString(byte[] bArray) {
StringBuffer sb = new StringBuffer(bArray.length);
String sTemp;
for (int i = 0; i < bArray.length; i++) {
sTemp = Integer.toHexString(0xFF & bArray[i]);
if (sTemp.length() < 2)
sb.append(0);
sb.append(sTemp.toUpperCase());
}
return sb.toString();
}
//    byte[]数组转换成十六进制字符串方法2:
/**
* 数组转成十六进制字符串
//     * @param byte[]
* @return HexString
*/
public static String toHexString1(byte[] b){
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < b.length; ++i){
buffer.append(toHexString1(b[i]));
}
return buffer.toString();
}
public static String toHexString1(byte b){
String s = Integer.toHexString(b & 0xFF);
if (s.length() == 1){
return "0" + s;
}else{
return s;
}
}
//    十六进制字符串转换字符串方法1:
/**
* 十六进制字符串转换成字符串
//     * @param hexString
* @return String
*/
public static String hexStr2Str(String hexStr) {
String str = "0123456789ABCDEF";
char[] hexs = hexStr.toCharArray();
byte[] bytes = new byte[hexStr.length() / 2];
int n;
for (int i = 0; i < bytes.length; i++) {
n = str.indexOf(hexs[2 * i]) * 16;
n += str.indexOf(hexs[2 * i + 1]);
bytes[i] = (byte) (n & 0xff);
}
return new String(bytes);
}
//    十六进制字符串转换字符串方法2:
/**
* 十六进制字符串转换字符串
//     * @param HexString
* @return String
*/
public static String toStringHex(String s) {
byte[] baKeyword = new byte[s.length() / 2];
for (int i = 0; i < baKeyword.length; i++) {
try {
baKeyword[i] = (byte) (0xff & Integer.parseInt(s.substring(
i * 2, i * 2 + 2), 16));
} catch (Exception e) {
e.printStackTrace();
}
}
try {
s = new String(baKeyword, "utf-8");// UTF-16le:Not
} catch (Exception e1) {
e1.printStackTrace();
}
return s;
}
public static void main(String[] args) {
//定义一个十进制值
int valueTen = 10080001;
//将其转换为十六进制并输出
String strHex = Integer.toHexString(valueTen).toUpperCase();
System.out.println(valueTen + " [十进制]---->[十六进制] " + strHex);
//将十六进制格式化输出
String strHex2 = String.format("%08x",valueTen).toUpperCase();
System.out.println(valueTen + " [十进制]---->[十六进制] " + strHex2);
System.out.println("==========================================================");
//定义一个十六进制值
String strHex3 = "00001322";
//将十六进制转化成十进制
int valueTen2 = Integer.parseInt(strHex3,16);
System.out.println(strHex3 + " [十六进制]---->[十进制] " + valueTen2);
System.out.println("==========================================================");
//可以在声明十进制时,自动完成十六进制到十进制的转换
int valueHex = 0x00001322;
System.out.println("int valueHex = 0x00001322 --> " + valueHex);
}
}
}
大家加油!!!

人已赞赏
Android文章

Android开发EditText 光标仿ios,默认在最后面,点击整栏也在最后面,点击文本光标在对应位置

2020-3-8 12:21:36

Android文章

Android开发ScrollView 嵌套 RecyclerView 滑动到底端 在滑动的时候出现卡顿(绝对管用)

2020-3-8 13:25:30

个人中心
购物车
优惠劵
今日签到
有新私信 私信列表
有新消息 消息中心
搜索