const char * const prefix = "yzafpnum KMGTPEZY";
const float prefix_xf[] = {
1e-24, 1e-21, 1e-18, 1e-15, 1e-12, 1e-9, 1e-6, 1e-3,
1e+1,
1e+3, 1e+6, 1e+9, 1e+12, 1e+15, 1e+18, 1e+21, 1e+24};

float hum_to_float(const char *s) {
    // This function stolen from either Rolf Neugebauer or Andrew Tolmach.
    // Probably Rolf.
    float a = 0.0f;
    int e = 0;
    int c;
    float sign = 1;

    c = *s++;

    if(c == '-') {
        sign = -1;
        c = *s++;
    }

    while(c != '\0' && isdigit(c)) {
        a = a * 10.0f + (c - '0');
        c = *s++;
    }

    if(c == '.') {
        while((c = *s++) != '\0' && isdigit(c)) {
            a = a * 10.0f + (c - '0');
            e = e - 1;
        }
    }

    if(c <= 'z' && c >= 'E') {
        for(int i = 0; prefix[i] != '\0'; i++) {
            if(c == prefix[i]){
                a *= prefix_xf[i];
                break;
            }
        }
    }

    while(e > 0) {
        a *= 10.0f;
        e--;
    }

    while(e < 0) {
        a *= 0.1f;
        e++;
    }

    return a * sign;
}