Java CRC-8 工具类
/**
* CRC-8
*
* <table width="400px" border="1" cellpadding="0" cellspacing="0">
* <tr>
* <th>名称</th>
* <th>多项式</th>
* <th>初始值</th>
* <th>异或值</th>
* <th>Bit反转</th>
* </tr>
* <tr>
* <td> CRC-8</td>
* <td align="center">0x07</td>
* <td align="center">0x00</td>
* <td align="center">0x00</td>
* <td align="center">MSB First</td>
* </tr>
* <tr>
* <td> CRC-8/DARC</td>
* <td align="center">0x39</td>
* <td align="center">0x00</td>
* <td align="center">0x00</td>
* <td align="center">LSB First</td>
* </tr>
* <tr>
* <td> CRC-8/ITU</td>
* <td align="center">0x07</td>
* <td align="center">0x00</td>
* <td align="center">0x55</td>
* <td align="center">MSB First</td>
* </tr>
* <tr>
* <td> CRC-8/MAXIM</td>
* <td align="center">0x31</td>
* <td align="center">0x00</td>
* <td align="center">0x00</td>
* <td align="center">LSB First</td>
* </tr>
* <tr>
* <td> CRC-8/ROHC</td>
* <td align="center">0x07</td>
* <td align="center">0xFF</td>
* <td align="center">0x00</td>
* <td align="center">LSB First</td>
* </tr>
* </table>
*
* @author unnamed
*
*/
public class CRC8Utils {
/**
* CRC-8
*
* <table width="400px" border="1" cellpadding="0" cellspacing="0">
* <tr>
* <th>多项式</th>
* <th>初始值</th>
* <th>异或值</th>
* <th>Bit反转</th>
* </tr>
* <tr>
* <td align="center">0x07</td>
* <td align="center">0x00</td>
* <td align="center">0x00</td>
* <td align="center">MSB First</td>
* </tr>
* </table>
*
* @param source
* @param offset
* @param length
* @return
*/
public static int CRC8(byte[] source, int offset, int length) {
int wCRCin = 0x00;
int wCPoly = 0x07;
for (int i = offset, cnt = offset + length; i < cnt; i++) {
for (int j = 0; j < 8; j++) {
boolean bit = ((source[i] >> (7 - j) & 1) == 1);
boolean c07 = ((wCRCin >> 7 & 1) == 1);
wCRCin <<= 1;
if (c07 ^ bit)
wCRCin ^= wCPoly;
}
}
wCRCin &= 0xFF;
return wCRCin ^= 0x00;
}
/**
* CRC-8/DARC
*
* <table width="400px" border="1" cellpadding="0" cellspacing="0">
* <tr>
* <th>多项式</th>
* <th>初始值</th>
* <th>异或值</th>
* <th>Bit反转</th>
* </tr>
* <tr>
* <td align="center">0x39</td>
* <td align="center">0x00</td>
* <td align="center">0x00</td>
* <td align="center">LSB First</td>
* </tr>
* </table>
*
* @param source
* @param offset
* @param length
* @return
*/
public static int CRC8_DARC(byte[] source, int offset, int length) {
int wCRCin = 0x00;
// Integer.reverse(0x39) >>> 24
int wCPoly = 0x9C;
for (int i = offset, cnt = offset + length; i < cnt; i++) {
wCRCin ^= ((long) source[i] & 0xFF);
for (int j = 0; j < 8; j++) {
if ((wCRCin & 0x01) != 0) {
wCRCin >>= 1;
wCRCin ^= wCPoly;
} else {
wCRCin >>= 1;
}
}
}
return wCRCin ^= 0x00;
}
/**
* CRC-8/ITU
*
* <table width="400px" border="1" cellpadding="0" cellspacing="0">
* <tr>
* <th>多项式</th>
* <th>初始值</th>
* <th>异或值</th>
* <th>Bit反转</th>
* </tr>
* <tr>
* <td align="center">0x07</td>
* <td align="center">0x00</td>
* <td align="center">0x55</td>
* <td align="center">MSB First</td>
* </tr>
* </table>
*
* @param source
* @param offset
* @param length
* @return
*/
public static int CRC8_ITU(byte[] source, int offset, int length) {
int wCRCin = 0x00;
int wCPoly = 0x07;
for (int i = offset, cnt = offset + length; i < cnt; i++) {
for (int j = 0; j < 8; j++) {
boolean bit = ((source[i] >> (7 - j) & 1) == 1);
boolean c07 = ((wCRCin >> 7 & 1) == 1);
wCRCin <<= 1;
if (c07 ^ bit)
wCRCin ^= wCPoly;
}
}
wCRCin &= 0xFF;
return wCRCin ^= 0x55;
}
/**
* CRC-8/MAXIM
*
* <table width="400px" border="1" cellpadding="0" cellspacing="0">
* <tr>
* <th>多项式</th>
* <th>初始值</th>
* <th>异或值</th>
* <th>Bit反转</th>
* </tr>
* <tr>
* <td align="center">0x31</td>
* <td align="center">0x00</td>
* <td align="center">0x00</td>
* <td align="center">LSB First</td>
* </tr>
* </table>
*
* @param source
* @param offset
* @param length
* @return
*/
public static int CRC8_MAXIM(byte[] source, int offset, int length) {
int wCRCin = 0x00;
// Integer.reverse(0x31) >>> 24
int wCPoly = 0x8C;
for (int i = offset, cnt = offset + length; i < cnt; i++) {
wCRCin ^= ((long) source[i] & 0xFF);
for (int j = 0; j < 8; j++) {
if ((wCRCin & 0x01) != 0) {
wCRCin >>= 1;
wCRCin ^= wCPoly;
} else {
wCRCin >>= 1;
}
}
}
return wCRCin ^= 0x00;
}
/**
* CRC-8/ROHC
*
* <table width="400px" border="1" cellpadding="0" cellspacing="0">
* <tr>
* <th>多项式</th>
* <th>初始值</th>
* <th>异或值</th>
* <th>Bit反转</th>
* </tr>
* <tr>
* <td align="center">0x07</td>
* <td align="center">0xFF</td>
* <td align="center">0x00</td>
* <td align="center">LSB First</td>
* </tr>
* </table>
*
* @param source
* @param offset
* @param length
* @return
*/
public static int CRC8_ROHC(byte[] source, int offset, int length) {
int wCRCin = 0xFF;
// Integer.reverse(0x07) >>> 24
int wCPoly = 0xE0;
for (int i = offset, cnt = offset + length; i < cnt; i++) {
wCRCin ^= ((long) source[i] & 0xFF);
for (int j = 0; j < 8; j++) {
if ((wCRCin & 0x01) != 0) {
wCRCin >>= 1;
wCRCin ^= wCPoly;
} else {
wCRCin >>= 1;
}
}
}
return wCRCin ^= 0x00;
}
}