C语言字符串和十六进制的相互转换方式

ゝ一世哀愁。 2022-12-24 01:49 248阅读 0赞

转载地址：[https://my.oschina.net/u/4309414/blog/3613889][https_my.oschina.net_u_4309414_blog_3613889]

一、将数组转换为十六进制同值的字符串

读取数组中的数字，打印成字符串的时候以2位大写的格式。

int arrayToStr(unsigned char *buf, unsigned int buflen, char *out)
      {
          char strBuf[33] = {0};
          char pbuf[32];
          int i;
          for(i = 0; i < buflen; i++)
          {
              sprintf(pbuf, "%02X", buf[i]);
              strncat(strBuf, pbuf, 2);
          }
          strncpy(out, strBuf, buflen * 2);
          printf("out = %s\n", out);
          return buflen * 2;
     }

二、将十六进制的字符串转换为十六进制数组

下面定义的字符串中的字符只能是0-F的字符，但是不区分大小写的，前面是安装两位为一个数字进行转换，最后一个数字如果还是两位的则正常转换，如果只剩一位的话则在前面补零输出。

int StringToHex(char *str, unsigned char *out, unsigned int *outlen)
      {
          char *p = str;
          char high = 0, low = 0;
          int tmplen = strlen(p), cnt = 0;
          tmplen = strlen(p);
          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;
     }

三、将十进制字符串转化为十进制数组

int StringToCom(char *str, unsigned char *out, int *outlen)
      {
          char *p = str;
          char high = 0, low = 0;
          int tmplen = strlen(p), cnt = 0;
          tmplen = strlen(p);
          if(tmplen % 2 != 0) return -1;
          while(cnt < tmplen / 2) //1213141516171819
          {
             out[cnt] = (*p - 0x30) * 10 + (*(++p) - 0x30);
             p++;
             cnt ++;
         }
         *outlen = tmplen / 2;
         return tmplen / 2;
     }

四、简单的使用方法

定义的参数有些为unsigned char，是因为在定义为char的时候，转换为十六进制之后，负数在表示的时候，难看！

#include "stdio.h"
      #include "stdlib.h"
      #include "string.h"
      
      unsigned char ArrayCom[16] = {
          11, 12, 13, 14, 15, 16, 17, 18,
          19, 20, 21, 22, 23, 24, 25, 26};
      unsigned char ArrayHex[16] = {
          0x2c, 0x57, 0x8f, 0x79, 0x27, 0xa9, 0x49, 0xd3,
         0xb5, 0x11, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
     
     char *strHex = "01aa0304050607083f0add0c0d0e0f00";
     char *strCom = "1D1213AB6FC1718B19202122232425A6";
     
     int main(int argc, const char *argv)
     {
         int cnt;
         char str[33] = {0};
         unsigned char out[33];
         arrayToStr(ArrayCom, 16, str);
         
         int outlen = 0;
         StringToHex(strCom, out, &outlen);
         for(cnt = 0; cnt < outlen; cnt ++)
         {
             printf("%02X ", out[cnt]);
         } 
         putchar(10);
     
         return 0;
     }

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