CRC校验码计算与校验函数

#include <iostream> using namespace std; int CalDivisorBinaryLen(int num); unsigned long int CRC_CalVal(unsigned char datas[],int len,unsigned long int divisor); int CheckCRC(unsigned char datas[],int len,unsigned long int divisor); int main() { cout<<"hello"<<endl; //unsigned char *arr = (unsigned char*)malloc(4); unsigned char arr[4] ={0x2C,0x9B,0x36,0x44}; unsigned long int result = CRC_CalVal(arr,16,121); cout<<"校验码是： "<<result+0<<endl; unsigned char *arr2 = (unsigned char*)malloc(2); arr2[0] = 0xB2; arr2[1] = 0x70; int checkflag = CheckCRC(arr2,12,19); cout<<"check result: "<<checkflag<<endl; cin>>arr; return -1; } ///**************************** ///计算CRC校验码 ///参数：datas 输入的数据帧 /// len 数据帧的长度，按bit算 /// divisor 除数 ///返回：CRC校验码 ///**************************** unsigned long int CRC_CalVal(unsigned char datas[],int len,unsigned long int divisor) { unsigned long int CRC = 0; int DivisorLen = CalDivisorBinaryLen(divisor); //计算除数的二进制位宽 int CRC_len = DivisorLen - 1; //CRC校验码的二进制长度=除数二进制位宽-1 int index = 0; unsigned long int Dividend = 0; //被除数 for(int i=0;i<len+CRC_len;i++) //在原数据帧后填充和CRC校验码长度相同的0 { index = i; unsigned char indexval = 0; if(index<len) { indexval = (datas[index/8]>>(7-index%8))&0x01; //数据帧中的数据一位一位读取到被除数中，读到补齐的数据时，填0 } Dividend = Dividend*2 + indexval; if(CalDivisorBinaryLen(Dividend)==DivisorLen) { Dividend = Dividend^divisor; //模2除法 } } CRC = Dividend; //最后的余数即为CRC校验码 return CRC; } ///**************************** ///计算num的二进制长度 ///参数：num 待求长度数 ///返回：长度 ///**************************** int CalDivisorBinaryLen(int num) { int len = 1; while(num>=2) { len++; num = num/2; } return len; } ///**************************** ///校验CRC ///参数：datas 输入的数据帧 /// len 数据帧的长度，按bit算 /// divisor 除数 ///返回：CRC校验结果 0代表校验正确，-1代表校验出错 ///**************************** int CheckCRC(unsigned char datas[],int len,unsigned long int divisor) { int checkresult = -1; int DivisorLen = CalDivisorBinaryLen(divisor); int index = 0; unsigned long int Dividend = 0; //被除数 unsigned char indexval = (datas[index/8]>>(7-index%8))&0x01; for(int i=0;i<len;i++) { index = i; indexval = (datas[index/8]>>(7-index%8))&0x01; Dividend = Dividend*2 + indexval; if(CalDivisorBinaryLen(Dividend)==DivisorLen) { Dividend = Dividend^divisor; } } if(Dividend==0) { checkresult = 0; } return checkresult; }