//
// Helper functions
//

char* dtostrf(double number, signed char width, unsigned char prec, char *s) {

    if(isnan(number)) {
        strcpy(s, "nan");
        return s;
    }
    if(isinf(number)) {
        strcpy(s, "inf");
        return s;
    }

    if(number > 4294967040.0 || number < -4294967040.0) {
        strcpy(s, "ovf");
        return s;
    }
    char* out = s;
    // Handle negative numbers
    if(number < 0.0) {
        *out = '-';
        ++out;
        number = -number;
    }

    // Round correctly so that print(1.999, 2) prints as "2.00"
    double rounding = 0.5;
    for(uint8_t i = 0; i < prec; ++i)
        rounding /= 10.0;

    number += rounding;

    // Extract the integer part of the number and print it
    unsigned long int_part = (unsigned long) number;
    double remainder = number - (double) int_part;
    out += sprintf(out, "%d", int_part);

    // Print the decimal point, but only if there are digits beyond
    if(prec > 0) {
        *out = '.';
        ++out;
    }

    while(prec-- > 0) {
        remainder *= 10.0;
    }
    sprintf(out, "%d", (int) remainder);

    return s;
}