[原创] ModBus数据CRC计算小工具

ModBus数据CRC计算小工具

/*
    20231230
*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <windows.h>
 
#define INPUT_BUF_SIZE   1024
#define OUTPUT_BUF_SIZE  (1024 + 1)
 
void input_data(char *input);
void deblank(char *str);
uint8_t string_to_hex(char *str, uint8_t *out, uint16_t output_buf_size, uint16_t *outlen);
uint16_t ModBusCRC16(uint8_t *data, uint16_t len);
uint8_t modbus_data_calc(char *input, uint8_t *output, uint16_t output_buf_size, uint16_t *outlen);
void output_data(uint8_t *output, uint16_t outlen);
 
int main(void)
{
    char input[INPUT_BUF_SIZE] = { 0 };
    uint8_t output[OUTPUT_BUF_SIZE] = { 0 };
    uint16_t outlen = 0;
    uint8_t ret;
     
    SetConsoleTitle("modbus_data_calc");
     
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 15);
    printf("\t\t\t\tmodbus_data_calc\t\t\t\t\n");
    printf(":02 03 04 00 EA FD C9\n");
    printf("02 03 04 00 EA FD C9 68 01\n\n");
     
    while(1)
    {
        printf(":");
         
        input_data(input);
        ret = modbus_data_calc(input, output, sizeof(output)/sizeof(*output), &outlen);
        if(ret != 0)
        {
            printf("err:%X\n", ret);
            getchar();
            return ret;
        }
         
        SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 6);
        printf("data length:%u\n", outlen);
        output_data(output, outlen);
        SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 15);
         
        printf("\n-----------------------\n\n");
    }
     
    return 0;
}
 
/*
    输入字符串
    input:输入buf指针
*/
void input_data(char *input)
{
    char ch;
     
    while ((ch = getchar()) != '\n')
    {
        *input = ch;
        ++input;
    }
    *input = '\0';
}
/*
    输出数据
    output:数组指针
    outlen:数组大小
*/
void output_data(uint8_t *output, uint16_t outlen)
{
    uint16_t i;
     
    for (i = 0; i < outlen; ++i)
    {
        printf("%02X ", output[i]);
    }
}
 
/*
    modbus_data_calc
    input:输入字符串buf指针
    output:输出uin8_t类型数组buf指针
    output_buf_size:输出uin8_t类型数组buf大小
    outlen:最终结果数据长度
     
    返回: ok(0) err(!0)
*/
uint8_t modbus_data_calc(char *input, uint8_t *output, uint16_t output_buf_size, uint16_t *outlen)
{
    uint16_t crc16;
    uint16_t tmplen;
    uint8_t ret;
     
    if(input == NULL || output == NULL)
    {
        return 0xFF;
    }
     
    memset(output, 0, output_buf_size); //清空输出buf
     
    ret = string_to_hex(input, output, output_buf_size, &tmplen); //输入字符串转数字放入数组
     
    if(ret != 0)
    {
        return ret;
    }
     
    crc16 = ModBusCRC16(output, tmplen); //计算CRC16
     
    output[tmplen] = (uint8_t)crc16; //结果数组添加CRC16校验
    output[tmplen+1] = (uint8_t)(crc16 >> 8);
     
    (*outlen) = tmplen + 2; //加2字节的CRC校验
     
    return 0;
}
 
/*
    计算CRC16校验
    data:数据buf
    len:数据长度
     
    返回 CRC16校验结果
*/
uint16_t ModBusCRC16(uint8_t *data, uint16_t len)
{
    uint16_t i, j, tmp, CRC16;
 
    CRC16 = 0xFFFF; // CRC寄存器初始值
    for (i = 0; i < len; i++)
    {
        CRC16 ^= data[i];
        for (j = 0; j < 8; j++)
        {
            tmp = (uint16_t)(CRC16 & 0x0001);
            CRC16 >>= 1;
            if (tmp == 1)
            {
                CRC16 ^= 0xA001; // 异或多项式
            }
        }
    }
    return CRC16;
}
 
/*
    删除字符串中的空格
    str:字符串
     
    返回:去除所有空格后的字符串
*/
void deblank(char *str)
{
    int i, j = 0;
    for (i = 0; str[i] != '\0'; i++) // 循环条件也可以写为 i<strlen(str)
    {
        if (str[i] != ' ')     // 也可以写为:if(str[i]==' ')
            str[j++] = str[i]; //           continue;
    }                          //       str[j++]=str[i];
    str[j] = '\0';
}
 
/*
    字符串转16进制数据
    str:输入字符串
    out:输出字符串
    output_buf_size:输出buf大小
    outlen:输出有效长度
     
    返回: ok(0) err(!0)
*/
uint8_t string_to_hex(char *str, uint8_t *out, uint16_t output_buf_size, uint16_t *outlen)
{
    char *p = str;
    char high = 0, low = 0;
    uint16_t tmplen = strlen(p), cnt = 0;
 
    deblank(str); // 去除字符串中所有的空格
 
    tmplen = strlen(p);
    if(tmplen > output_buf_size) // 输入字符超过输出buf大小
    {
        return 0xFE;
    }
     
    while (cnt < (tmplen / 2))
    {
        high = ((*p > '9') && ((*p <= 'F') || (*p <= 'f'))) ? *p - 48 - 7 : *p - 48;
        low = (*(++p) > '9' && ((*p <= 'F') || (*p <= 'f'))) ? *(p)-48 - 7 : *(p)-48;
        out[cnt] = ((high & 0x0f) << 4 | (low & 0x0f));
        p++;
        cnt++;
    }
    if (tmplen % 2 != 0)
        out[cnt] = ((*p > '9') && ((*p <= 'F') || (*p <= 'f'))) ? *p - 48 - 7 : *p - 48;
 
    if (outlen != NULL)
        *outlen = tmplen / 2 + tmplen % 2;
     
    //return tmplen / 2 + tmplen % 2;
    return 0;
}