hexsz2int  16進数列を整数に変換する

int hexsz2int(char *str);

str  16進数ASCIZ文字列

16進数列を表す整数

int hexsz2int(char *str)
{
    int val;
    int sign;
    
    while (*str == ' ' || *str == '\t') str++;
    sign = 1;
    if (*str == '+') str++;
    else if (*str == '-') {
        sign = -1;
        str++;
    }
    val = 0;
    while (*str >= '0' && *str <= '9' ||
           *str >= 'A' && *str <= 'F' ||
           *str >= 'a' && *str <= 'f') {
        val <<= 4;
        if      (*str >= '0' && *str <= '9') val += *str - '0';
        else if (*str >= 'A' && *str <= 'F') val += *str - 'A' + 10;
        else                                 val += *str - 'a' + 10;
        str++;
    }

    return sign == 1 ? val : -val;
}