摘要:
CRC-16 CCITT-FALSE格式校验函数 CRC-16校验产生2个字节长度的数据校验码,通过计算得到的校验码和获得的校验码比较,用于验证...
CRC-16 CCITT-FALSE格式校验函数
CRC-16校验产生2个字节长度的数据校验码,通过计算得到的校验码和获得的校验码比较,用于验证获得的数据的正确性。基本的CRC-16校验算法实现。同应用规范通过对输入数据前处理和输出数据后处理的方式不同,又产生了不同的应用规范校验函数,这里介绍CCITT-FALSE格式的CRC-16校验函数。CCITT-FALSE格式对输入数据,预置值为0XFFFF(当做最初的余数)。
这里分享java实现crc_16_CCITT_False核验码算法工具类
代码:
package com.tehn.utils;
/**
* @Desc: Crc16进制工具类
* @Author:DurkBlue
* @Package:com.tehn.utils
* @Project:meteorology-six-elements
* @name:Crc16Utils
* @Date:2024/7/23 0023 15:34
* @Filename:Crc16Utils
*/
public class Crc16Utils {
/**
* CRC-16/CCITT-FALSE x16+x12+x5+1 算法
*
* info
* Name:CRC-16/CCITT-FAI
* Width:16
* Poly:0x1021
* Init:0xFFFF
* RefIn:False
* RefOut:False
* XorOut:0x0000
*
* @param hexString
* @param
* @return
*/
public static String crc_16_CCITT_False(String hexString) {
byte[] destByte = new byte[hexString.length()/2];
int j=0;
for(int i=0;i<destByte.length;i++) {
byte high = (byte) (Character.digit(hexString.charAt(j), 16) & 0xff);
byte low = (byte) (Character.digit(hexString.charAt(j + 1), 16) & 0xff);
destByte[i] = (byte) (high << 4 | low);
j+=2;
}
int crc = 0xffff; // 初始值
int polynomial = 0x1021; // 聚合值
for (int index = 0; index < destByte.length; index++) {
byte b = destByte[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;
String strCrc = Integer.toHexString(crc).toUpperCase();
return strCrc;
}
}
java实现modbus CRC的计算方法一
public class CrcUtil { public static void main(String[] args) { String hexString = "020358449118d14492c004448d6c604492139a4496da2e449683f9447eddb8447aa437364c83a835af507535af507535af507535af507535af507535af50754e8834a94d8e60744a8b70344bd9cbf04d99c2fe4a2a13ef41bdb935"; String hex = "02030A00002C"; System.out.println(crc_16_CCITT_False(hexString)); System.out.println(crc16B(SystemUtil.hexToBytes(hexString))); System.out.println(crc_16_modbus(hex)); System.out.println(crc_16_modbus(hexString)); } /** * 增加modbus的CRC低位在前高位在后的校验位后发送 * * @param message * @return */ public static String addModbusCrc(String message) { String messageToSend = message + CrcUtil.crc_16_modbus(message); return messageToSend; } /** * 计算Modbus CRC-16 * * @param hexString * @return */ public static String crc_16_modbus(String hexString) { // Modbus CRC-16生成多项式,x^16 + x^15 + x^2 + 1 int POLYNOMIAL = 0xA001; // 将十六进制字符串转换为字节数组 byte[] bytes = SystemUtil.hexToBytes(hexString); // 初始CRC寄存器值 int crc = 0xFFFF; // 对每个字节进行处理 for (byte b : bytes) { crc ^= b & 0xFF; // 字节与CRC寄存器进行异或 for (int i = 8; i != 0; i--) { if ((crc & 0x0001) != 0) { // 如果最低位为1 crc >>= 1; // 右移一位 crc ^= POLYNOMIAL; // 与多项式进行异或 } else { // 如果最低位为0 crc >>= 1; // 右移一位 } } } // 返回CRC的十六进制字符串表示,不带前缀"0x" String crcString = String.format("%04x", crc & 0xFFFF); //处理大小端翻转的情况,CRC校验码低位在前,高位在后 crcString = flipCRC(crcString); return crcString; } /** * 处理大小端翻转的情况,CRC校验码低位在前,高位在后 * * @param crc * @return */ private static String flipCRC(String crc) { // 检查输入的CRC长度,假设为4位,可以根据实际情况进行调整 if (crc.length() != 4) { throw new IllegalArgumentException("CRC应为4位长度"); } // 翻转CRC码 StringBuilder flipped = new StringBuilder(); flipped.append(crc.charAt(2)).append(crc.charAt(3)).append(crc.charAt(0)).append(crc.charAt(1)); return flipped.toString(); } private static int[] table = { 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 }; public static String crc16B(byte[] bytes) { int crc = 0xFFFF; for (byte b : bytes) { char ch = (char) (b & 0xFF); crc = ((crc << 8) & 0xFF00) ^ table[((crc >> 8) & 0xFF) ^ ch]; } return String.format("%04x", crc); } /** * CRC-16/CCITT-FALSE x16+x12+x5+1 算法 * <p> * info * Name:CRC-16/CCITT-FAI * Width:16 * Poly:0x1021 * Init:0xFFFF * RefIn:False * RefOut:False * XorOut:0x0000 * * @param hexString * @param * @return */ public static String crc_16_CCITT_False(String hexString) { byte[] destByte = new byte[hexString.length() / 2]; int j = 0; for (int i = 0; i < destByte.length; i++) { byte high = (byte) (Character.digit(hexString.charAt(j), 16) & 0xff); byte low = (byte) (Character.digit(hexString.charAt(j + 1), 16) & 0xff); destByte[i] = (byte) (high << 4 | low); j += 2; } int crc = 0xffff; // initial value int polynomial = 0x1021; // poly value for (int index = 0; index < destByte.length; index++) { byte b = destByte[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; String strCrc = Integer.toHexString(crc).toUpperCase(); return strCrc; } }
第二种方法实现CRC_16/MODBUS 算法
package com.tehn.utils;
import org.apache.commons.lang3.StringUtils;
/**
* @Desc: Crc16进制工具类实现CRC-16/MODBUS算法
* @Author:DurkBlue
* @Package:com.tehn.utils
* @Project:meteorology-six-elements
* @name:Crc16Utils
* @Date:2024/7/23 0023 15:34
* @Filename:Crc16Utils
*/
public class Crc16Utils {
private static final Integer ONE = 1;
private static final Integer TWO = 2;
private static final Integer HEX = 16;
private static final String NUL = "";
private static final String SPACE = " ";
private static final String ASCII = "US-ASCII";
/**
* 根据报文byte数组,获取CRC-16 16进制字符串<p>
* 48 4C 01 00 01 00 00 05 00 00 >> 0xE647
*
* @param data 报文数组
* @return CRC值(16进制)
*/
public static String getCrc16HexStr(String data) {
return crcToHexStr(getCrc16(data));
}
/**
* 根据报文byte数组,获取CRC-16 int值<p>
* 48 4C 01 00 01 00 00 05 00 00 >> 58951
*
* @param data 报文数组
* @return CRC值(10进制)
*/
public static int getCrc16(String data) {
if (StringUtils.isBlank(data)) {
// ----- 校验:报文字符串不能为空,否则抛异常
throw new RuntimeException("The string cannot be empty!");
}
return getCrc16(hexStrToByteArr(data));
}
/**
* 根据报文byte数组,获取CRC-16 16进制字符串<p>
* {0x48, 0x4C, 0x01, 0x00, 0x01, 0x00, 0x00, 0x05, 0x00, 0x00} >> 0xE647
*
* @param data 报文数组
* @return CRC值(16进制)
*/
public static String getCrc16HexStr(byte[] data) {
return crcToHexStr(getCrc16(data));
}
/**
* 根据报文byte数组,获取CRC-16 int值<p>
* {0x48, 0x4C, 0x01, 0x00, 0x01, 0x00, 0x00, 0x05, 0x00, 0x00} >> 58951
*
* @param data 报文数组
* @return CRC值(10进制)
*/
public static int getCrc16(byte[] data) {
if (data.length == 0) {
// ----- 校验:报文数组不能为空,否则抛异常
throw new RuntimeException("The array cannot be empty!");
}
// ----- 预置一个CRC寄存器,初始值为0xFFFF
int crc = 0xFFFF;
byte byteLen;
boolean flag;
for (byte item : data) {
// ----- 循环,将每数据帧中的每个字节与CRC寄存器中的低字节进行异或运算
crc ^= ((int) item & 0x00FF);
byteLen = 8;
while (byteLen > 0) {
// ----- 判断寄存器最后一位是 1\0:[true: 1; false: 0]
flag = (crc & ONE) == ONE;
// ----- 将寄存器右移1位,最高位自动补0
crc >>= 1;
if (flag) {
// ----- 如果右移出来的位是 1:将寄存器与固定值 0xA001 异或运算
// ----- 如果右移出来的位是 0:不做处理,进行下一次右移
// ----- 直到处理完整个字节的8位
crc ^= 0xA001;
}
byteLen--;
}
}
// ----- 最终寄存器得值就是CRC的值,返回
return crc;
}
/**
* 将16进制字符串转换为16进制Byte数组<p>
* 48 4C 01 00 01 00 00 05 00 00 >> {0x48, 0x4C, 0x01, 0x00, 0x01, 0x00, 0x00, 0x05, 0x00, 0x00}
*
* @param str 报文字符串
* @return 报文数组
*/
private static byte[] hexStrToByteArr(String str) {
str = str.replaceAll(SPACE, NUL);
int strLen = str.length();
if ((strLen & ONE) == ONE) {
// ----- 报文字符串必须是以一个字节为单位(两位为一个字节),所以当去除所有空格后的报文长度为单数时说明报文错误
throw new RuntimeException("Incorrect message format!");
}
byte[] result = new byte[strLen / TWO];
// ----- 两位一个字节
for (int i = 0; i < strLen; i += TWO) {
String temp = str.substring(i, i + TWO);
result[i / TWO] = (byte) Integer.parseInt(temp, HEX);
}
return result;
}
/**
* 将CRC-16值转换成16进制字符串,且保持最小长度为4位<p>
* 58951 >> E647
*
* @param data CRC值(10进制)
* @return CRC值(16进制)
*/
private static String crcToHexStr(int data) {
String crcStr = Integer.toHexString(data).toUpperCase();
int size = 4 - crcStr.length();
StringBuilder builder = new StringBuilder();
// ---- 长度不够 4 位高位自动补0
while (size > 0) {
builder.append("0");
size--;
}
return builder.append(crcStr).toString();
}
/**
* 输出16进制与长度, 提供给 C++ CRC校验方法 测试 代码使用
*
* @param str 16进制字符串
*/
public static void printHexStr(String str) {
String[] split = str.split(SPACE);
StringBuilder builder = new StringBuilder();
builder.append(" unsigned char arr[] = {");
for (int i = 0; i < split.length; i++) {
builder.append("0x").append(split[i]);
if (i < split.length - 1) {
builder.append(", ");
}
}
builder.append("};");
System.out.println(builder.toString());
System.out.println(" int len = " + split.length + ";");
}
}
还没有评论,来说两句吧...