Binary转换成Hex字符串

　　想调优别人的代码，网上搜索一下Binary to Hexstring的转换，全是利用printf、scanf之类实现的，效率好低，还是自己想个简单的办法吧！

.......此处省略一万字.......

改进后的方法：

 int tohex(void* str, int strlen, char *ascii, int size)
 {
     if(strlen == || str== NULL || ascii==NULL)
     {
         if(NULL != ascii)
             ascii[]=0x00;
         return ;
     }

      char* p1 = ascii;//new  char[len*2+1];
     unsigned char* p2 = (unsigned char*)str;
     int i = , j = ;
     char dict[]={'','','','','','','','','','','A','B','C','D','E','F'};
     bool blCuted = false;
     for( i = ; i < strlen; ++i)
     {
         p1[j] = dict[ (p2[i] >> )];
         p1[j+] = dict[p2[i] & 0x0F];
         j+=;

         if(j > size){
             blCuted = true;
             break;
         }
     }
     if(blCuted)
         j-= ;
     p1[j]  =0x00;
     return j;
 }    

改进前的方法（抄的）：

 int BCD2ASC(const char *str, int strlen,char *ascii, int size)
 {
     int    i = , p = , l = ;
     byte ch;

     if(strlen == || str== NULL || ascii==NULL)
         return NULL;

     bool blCuted = false;
     while(i<strlen)
     {
         ch = str[i++];
         l += ;
         if(l > size){
             blCuted = true;
             break;
         }
         p += sprintf(ascii+p, "%02X", ch);
     }

     if(blCuted)
         l-= ;
     return l;
 }

测试代码：

  int main( )
   {
       int a=0x1234;
       int b=0xabcd;
       char *bistr="\x12\x34\x56\x78\x90\xab\xcd\xef\xe1\xf9\x1f\x1e\x00";
       char szTmp[*] = {};
  tohex(&a, sizeof(int),  szTmp, sizeof(szTmp)); cout << szTmp << endl;
     tohex(&b, sizeof(int),  szTmp, sizeof(szTmp)); cout << szTmp << endl;
      tohex(bistr, strlen(bistr),  szTmp, sizeof(szTmp)); cout << szTmp << endl;

      FILE* fp = fopen("D:\\testbinary.bi", "rb");
      char szBinary[*] = {};
      int ired = fread(szBinary, , *-, fp);
      cout << "readlen:" << ired <<endl;

      DWORD dwB = GetTickCount();
      for(int i = ; i < ; ++i)
      {
          tohex(szBinary, ired, szTmp, sizeof(szTmp)-); //i=1w,<200ms
          cout << szTmp << endl;
          BCD2ASC(szBinary, ired, szTmp, sizeof(szTmp)-); //i=1w,9000ms
          cout << szTmp << endl;
      }
      DWORD dwE = GetTickCount();

      cout << "cost:" << dwE-dwB << "ms" <<endl;

      fclose(fp);
      return ;
 }

效率差的不是一条街，你可以try一下。