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 == 0|| str== NULL || ascii==NULL)
    {
        if(NULL != ascii)
            ascii[0]=0x00;
        return 0;
    }

     char* p1 = ascii;//new  char[len*2+1];
    unsigned char* p2 = (unsigned char*)str;
    int i = 0, j = 0;
    char dict[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
    bool blCuted = false;
    for( i = 0; i < strlen; ++i)
    {
        p1[j] = dict[ (p2[i] >> 4)];
        p1[j+1] = dict[p2[i] & 0x0F];
        j+=2;

        if(j > size){
            blCuted = true;
            break;
        }
    }
    if(blCuted)
        j-=2 ;
    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 = 0, p = 0, l = 0;
    byte ch;

    if(strlen == 0|| str== NULL || ascii==NULL)
        return NULL;

    bool blCuted = false;
    while(i<strlen)
    {
        ch = str[i++];
        l += 2;
        if(l > size){
            blCuted = true;
            break;
        }
        p += sprintf(ascii+p, "%02X", ch);
    }

    if(blCuted)
        l-=2 ;
    return l;
}

测试代码：

 int main( ) 
  {
      int a=0x1234;
      int b=0xabcd;
      char *bistr="x12x34x56x78x90xabxcdxefxe1xf9x1fx1ex00";
      char szTmp[1024*10] = {0};
 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[1024*5] = {0};
     int ired = fread(szBinary, 1, 1024*5-1, fp);
     cout << "readlen:" << ired <<endl;

     DWORD dwB = GetTickCount();
     for(int i = 0; i < 1; ++i) 
     {
         tohex(szBinary, ired, szTmp, sizeof(szTmp)-1024); //i=1w,<200ms
         cout << szTmp << endl;
         BCD2ASC(szBinary, ired, szTmp, sizeof(szTmp)-1024); //i=1w,9000ms
         cout << szTmp << endl;
     }
     DWORD dwE = GetTickCount();

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

     fclose(fp);
     return 0;
}

效率差的不是一条街，你可以try一下。