向前辈致敬 strspn

把8位的CHAR型数据分解为：前５位和后３位，这样２^5 = 32个ＣＨＡＲ型数＋值就可表示所有的ＣＨＡＲ型数据
这样做的好处：在给出子串后，不用比较256次，最多比较32次即可判断出是否一个数在子串中
/***
*int strspn(string, control) - find init substring of control chars
*
*Purpose:
*       Finds the index of the first character in string that does belong
*       to the set of characters specified by control.  This is
*       equivalent to the length of the initial substring of string that
*       consists entirely of characters from control.  The '\0' character
*       that terminates control is not considered in the matching process.
*
*Entry:
*       char *string - string to search
*       char *control - string containing characters not to search for
*
*Exit:
*       returns index of first char in string not in control
*
*Exceptions:
*
*******************************************************************************/
int strspn(const char * string, const char * control)
{
    unsigned char map[32] = {0};
    size_t count;

    printf("lx_strspn %s control %s\r\n", string, control);
    while(*control != 0)
    {
        map[*control >> 3] |= (1 << (*control & 7));
        control++;
    }

    count = 0;
    while(map[*string >>3] & (1 << (*string & 7)))
    {
        printf("%d %d %d \r\n", *string >>3, *string & 7, map[*string >>3]);
        count++;
        string++;
    }

    return count;
}