CRC-CCITT算法如何写

CRC-CCITT算法怎么写
Consider the n data bits as the coefficients of a polynomial M(x) of degree n-1, associating the MSB of the zero-th octet 
with xn-1 and the LSB of the last octet with x0. Define the generator polynomial, GH(x), and the inversion polynomial, 
IH(x). 
 GH(x) = x16 + x12 + x5 + 1 (B.15) 
 IH(x) = x15 + x14 + x13 + ... + x2 + x + 1 (B.16) 
The CRC polynomial, FH(x), is then computed from the formula: 
 FH(x) = (x16 M(x) mod GH(x)) + IH(x) (B.17) 
modulo 2, i.e. in GF(2). 
The coefficients of FH(x) are placed in the CRC field with the MSB of the zero-th octet of the CRC corresponding to 
x15 and the LSB of the next octet of the CRC corresponding to x0. For the CRC-CCITT calculation the initial remainder 
shall be 0x0000

以上是我所使用crc-ccitt协议的描述，请问该怎么写算法，别从网上复制了，我从网上找的都不对。
生成多项式：GH(x) = x16 + x12 + x5 + 1
反转多项式：IH(x) = x15 + x14 + x13 + ... + x2 + x + 1
CRC多项式：FH(x) = (x16 M(x) mod GH(x)) + IH(x)
这是关键信息，请问具体算法该怎么写，完全搞不懂啊

------解决方案--------------------
CRC16的C语言代码：

typedef unsigned short uint16_t;
typedef unsigned char BYTE;

uint16_t crc16_ccitt(BYTE *ucbuf, int iLen)
{
uint16_t crc = 0xFFFF; // initial value
uint16_t polynomial = 0x1021; // 0001 0000 0010 0001 (0, 5, 12)

for (int j = 0; j < iLen; ++j) {
for (int i = 0; i < 8; i++) {
char bit = ((ucbuf[j] >> (7-i) & 1) == 1);
char c15 = ((crc >> 15 & 1) == 1);
crc <<= 1;
if (c15 ^ bit) crc ^= polynomial;
}
}

crc &= 0xffff;

return crc;
}