Boost CRC 16 bit

Question

使用在线crc计算器，我知道crc-CCITT（0xFFFF）的32311E333530（十六进制）=E558（十六进制。如何使用boost crc实现这一点？

    std::string crc_str = "32311E333530";
    boost::crc_16_type result;
    result.process_bytes(crc_str.data(), crc_str.length());
    std::cout << "checksum = " << result.checksum();

当E558（十六进制）=58712（十进制）时，校验和生成59589（十进制）=E8C5（十六进制。

我的串行设备用户手册上写着：

unsigned short calculate_crc16(char *data_ptr, unsigned short data_length)
{
    unsigned short index;
    unsigned short new_crc = 0xFFFF;
    //Loop through the entire buffer array of data
    for (index = 0; index < data_length; index++)
    {
        new_crc = (new_crc << 8) ^ crc_table[(new_crc >> 8) ^ (*data_ptr++)];
    }
    return(new_crc);
}
static const unsigned short crc_table[256] =
{
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
};

Answer 1

更新

您混淆了ascii字符串和字节数组。不是一回事。

这将产生您期望的结果：

int main()
{
    const unsigned char data[] = {0x32, 0x31, 0x1E, 0x33, 0x35, 0x30};
    boost::crc_ccitt_type result;
    result.process_bytes(data, 6);
    std::cout << "checksum = " << std::hex << result.checksum() << std::endl;
    return 0;
}

打印：checksum = e558

---

旧答案

因为对于CRC-16和CRC-CCITT，该字符串的CRC肯定分别是xE8C5或0xDDF6。

通过calculate_crc16运行"32311E333530"，正如您从您的书的代码中发布的那样

int main()
{
    std::string crc_str = "32311E333530";
    unsigned result = calculate_crc16(crc_str.c_str(), crc_str.length());
    std::cout << "checksum = " << std::hex << result << std::endl;
    return 0;
}

打印：

checksum = ddf6

使用crc_citt_type通过Boost运行相同的字符串，如下所示：

int main()
{
    std::string crc_str = "32311E333530";
    boost::crc_ccitt_type result;
    result.process_bytes(crc_str.data(), crc_str.length());
    std::cout << "checksum = " << std::hex << result.checksum() << std::endl;
    return 0;
}

打印：

checksum = ddf6

因此Boost代码与您的串行手册中的代码输出相匹配。

在这个在线crc计算器中键入32311E333530（无引号）会生成以下内容：

"32311E333530"
1 byte checksum 112
CRC-16  0xE8C5
CRC-16 (Modbus) 0xEAA1
CRC-16 (Sick)   0x9254
CRC-CCITT (XModem)  0x590F
CRC-CCITT (0xFFFF)  0xDDF6
CRC-CCITT (0x1D0F)  0xF065
CRC-CCITT (Kermit)  0xF2EC
CRC-DNP 0x8034
CRC-32  0xFB5DA62C

请注意，CRC-16是E8C5，正如您原来的boost代码所报告的那样。CRC-CCITT也匹配。

那么问题出在哪里呢？ccitt的boost代码与手册的代码以及在线工具都匹配。crc-16的提升结果也与我的在线计算器所说的相匹配。