#define CVTBUFSIZE 80
#define NULL        (char *)0

typedef unsigned int size_t;

double my_modf(double value, double *intpart)
{
	long i;
	i = (long)value;
	*intpart = (double)i;
	return value - *intpart;
}

static char *cvt(double arg, int ndigits, int *decpt, int *sign, char *buf, int eflag)
{
	int r2;
	double fi, fj;
	char *p, *p1;

	if (ndigits < 0) ndigits = 0;
	if (ndigits >= CVTBUFSIZE - 1) ndigits = CVTBUFSIZE - 2;
	r2 = 0;
	*sign = 0;
	p = &buf[0];
	if (arg < 0) {
		*sign = 1;
		arg = -arg;
		}
	arg = my_modf(arg, &fi);
	p1 = &buf[CVTBUFSIZE];

	if (fi != 0) {
		p1 = &buf[CVTBUFSIZE];
		while (fi != 0) {
			fj = my_modf(fi / 10, &fi);
			*--p1 = (int)((fj + .03) * 10) + '0';
			r2++;
			}
		while (p1 < &buf[CVTBUFSIZE]) *p++ = *p1++;
		}
	else if (arg > 0) {
		while ((fj = arg * 10) < 1) {
			arg = fj;
			r2--;
			}
		}
	p1 = &buf[ndigits];
	if (eflag == 0) p1 += r2;
	*decpt = r2;
	if (p1 < &buf[0]) {
		buf[0] = '\0';
		return buf;
		}
	while (p <= p1 && p < &buf[CVTBUFSIZE]) {
		arg *= 10;
		arg = my_modf(arg, &fj);
		*p++ = (int) fj + '0';
		}
	if (p1 >= &buf[CVTBUFSIZE]) {
		buf[CVTBUFSIZE - 1] = '\0';
		return buf;
		}
	p = p1;
	*p1 += 5;
	while (*p1 > '9') {
		*p1 = '0';
		if (p1 > buf) ++*--p1;
		else {
			*p1 = '1';
			(*decpt)++;
			if (eflag == 0) {
				if (p > buf) *p = '0';
				p++;
				}
			}
		}
	*p = '\0';
	return buf;
}

/*
char *ecvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf)
{
	return cvt(arg, ndigits, decpt, sign, buf, 1);
}

char *fcvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf)
{
	return cvt(arg, ndigits, decpt, sign, buf, 0);
}
*/

#define ZEROPAD 1               // Pad with zero
#define SIGN    2               // Unsigned/signed long
#define PLUS    4               // Show plus
#define SPACE   8               // Space if plus
#define LEFT    16              // Left justified
#define SPECIAL 32              // 0x
#define LARGE   64              // Use 'ABCDEF' instead of 'abcdef'

#define is_digit(c) ((c) >= '0' && (c) <= '9')

static char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
static char *upper_digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

static size_t strnlen(const char *s, size_t count)
{
	const char *sc;
	for (sc = s; *sc != '\0' && count--; ++sc);
	return sc - s;
}

static int skip_atoi(const char **s)
{
	int i = 0;
	while (is_digit(**s)) i = i*10 + *((*s)++) - '0';
	return i;
}

static char *number(char *str, long num, int base, int size, int precision, int type)
{
	char c, sign, tmp[66];
	char *dig = digits;
	int i;

	if (type & LARGE)  dig = upper_digits;
	if (type & LEFT) type &= ~ZEROPAD;
	if (base < 2 || base > 36) return NULL;

	c = (type & ZEROPAD) ? '0' : ' ';
	sign = 0;
	if (type & SIGN) {
		if (num < 0) {
			sign = '-';
			num = -num;
			size--;
			}
		else if (type & PLUS) {
			sign = '+';
			size--;
			}
		else if (type & SPACE) {
			sign = ' ';
			size--;
			}
		}

	if (type & SPECIAL) {
		if (base == 16) size -= 2;
		else if (base == 8) size--;
		}

	i = 0;

	if (num == 0) tmp[i++] = '0';
	else {
		while (num != 0) {
			tmp[i++] = dig[((unsigned long) num) % (unsigned) base];
			num = ((unsigned long) num) / (unsigned) base;
			}
		}

	if (i > precision) precision = i;
	size -= precision;
	if (!(type & (ZEROPAD | LEFT))) while (size-- > 0) *str++ = ' ';
	if (sign) *str++ = sign;

	if (type & SPECIAL) {
		if (base == 8) *str++ = '0';
		else if (base == 16) {
			*str++ = '0';
			*str++ = digits[33];
			}
		}

	if (!(type & LEFT)) while (size-- > 0) *str++ = c;
	while (i < precision--) *str++ = '0';
	while (i-- > 0) *str++ = tmp[i];
	while (size-- > 0) *str++ = ' ';

	return str;
}

static char *eaddr(char *str, unsigned char *addr, int size, int precision, int type)
{
	char tmp[24];
	char *dig = digits;
	int i, len;

	if (type & LARGE)  dig = upper_digits;
	len = 0;
	for (i = 0; i < 6; i++) {
		if (i != 0) tmp[len++] = ':';
		tmp[len++] = dig[addr[i] >> 4];
		tmp[len++] = dig[addr[i] & 0x0F];
		}

	if (!(type & LEFT)) while (len < size--) *str++ = ' ';
	for (i = 0; i < len; ++i) *str++ = tmp[i];
	while (len < size--) *str++ = ' ';
	return str;
}

static char *iaddr(char *str, unsigned char *addr, int size, int precision, int type)
{
	char tmp[24];
	int i, n, len;

	len = 0;
	for (i = 0; i < 4; i++) {
		if (i != 0) tmp[len++] = '.';
		n = addr[i];

		if (n == 0) tmp[len++] = digits[0];
		else {
			if (n >= 100) {
			tmp[len++] = digits[n / 100];
			n = n % 100;
			tmp[len++] = digits[n / 10];
			n = n % 10;
			}
			else if (n >= 10) {
				tmp[len++] = digits[n / 10];
				n = n % 10;
				}
			tmp[len++] = digits[n];
			}
		}

	if (!(type & LEFT)) while (len < size--) *str++ = ' ';
	for (i = 0; i < len; ++i) *str++ = tmp[i];
	while (len < size--) *str++ = ' ';
	return str;
}

static void cfltcvt(double value, char *buffer, char fmt, int precision)
{
	int decpt, sign, exp, pos;
	char *digits = NULL;
	char cvtbuf[CVTBUFSIZE];
	int capexp = 0;
	int magnitude;

/*
	if (fmt == 'G' || fmt == 'E') {
		capexp = 1;
		fmt += 'a' - 'A';
		}

	if (fmt == 'g') {
		digits = ecvtbuf(value, precision, &decpt, &sign, cvtbuf);
		magnitude = decpt - 1;
		if (magnitude < -4  ||  magnitude > precision - 1) {
			fmt = 'e';
			precision -= 1;
			}
		else {
			fmt = 'f';
			precision -= decpt;
			}
		}

	if (fmt == 'e') {
		digits = ecvtbuf(value, precision + 1, &decpt, &sign, cvtbuf);

		if (sign) *buffer++ = '-';
		*buffer++ = *digits;
		if (precision > 0) *buffer++ = '.';
		memcpy(buffer, digits + 1, precision);
		buffer += precision;
		*buffer++ = capexp ? 'E' : 'e';

		if (decpt == 0) {
			if (value == 0.0) exp = 0;
			else exp = -1;
			}
		else exp = decpt - 1;

		if (exp < 0) {
			*buffer++ = '-';
			exp = -exp;
			}
		else *buffer++ = '+';

		buffer[2] = (exp % 10) + '0';
		exp = exp / 10;
		buffer[1] = (exp % 10) + '0';
		exp = exp / 10;
		buffer[0] = (exp % 10) + '0';
		buffer += 3;
		}
	else */ if (fmt == 'f') {
		digits = cvt(value, precision, &decpt, &sign, cvtbuf, 0); // fcvtbuf(value, precision, &decpt, &sign, cvtbuf);
		if (sign) *buffer++ = '-';
		if (*digits) {
			if (decpt <= 0) {
				*buffer++ = '0';
				*buffer++ = '.';
				for (pos = 0; pos < -decpt; pos++) *buffer++ = '0';
				while (*digits) *buffer++ = *digits++;
				}
			else {
				pos = 0;
				while (*digits) {
					if (pos++ == decpt) *buffer++ = '.';
					*buffer++ = *digits++;
					}
				}
			}
		else {
			*buffer++ = '0';
			if (precision > 0) {
				*buffer++ = '.';
				for (pos = 0; pos < precision; pos++) *buffer++ = '0';
				}
			}
		}

	*buffer = '\0';
}

static void forcdecpt(char *buffer)
{
	while (*buffer) {
		if (*buffer == '.') return;
		if (*buffer == 'e' || *buffer == 'E') break;
		buffer++;
		}

	if (*buffer) {
		int n = strlen(buffer);
		while (n > 0) {
			buffer[n + 1] = buffer[n];
			n--;
			}
		*buffer = '.';
		}
	else {
		*buffer++ = '.';
		*buffer = '\0';
		}
}

static void cropzeros(char *buffer)
{
	char *stop;

	while (*buffer && *buffer != '.') buffer++;
	if (*buffer++) {
		while (*buffer && *buffer != 'e' && *buffer != 'E') buffer++;
		stop = buffer--;
		while (*buffer == '0') buffer--;
		if (*buffer == '.') buffer--;
		while (*++buffer = *stop++);
		}
}

static char *flt(char *str, double num, int size, int precision, char fmt, int flags)
{
	char tmp[80];
	char c, sign;
	int n, i;

	// Left align means no zero padding
	if (flags & LEFT) flags &= ~ZEROPAD;

	// Determine padding and sign char
	c = (flags & ZEROPAD) ? '0' : ' ';
	sign = 0;
	if (flags & SIGN) {
		if (num < 0.0) {
			sign = '-';
			num = -num;
			size--;
			}
		else if (flags & PLUS) {
			sign = '+';
			size--;
			}
		else if (flags & SPACE) {
			sign = ' ';
			size--;
			}
		}

	// Compute the precision value
	if (precision < 0) precision = 6; // Default precision: 6
	else if (precision == 0 && fmt == 'g') precision = 1; // ANSI specified

	// Convert floating point number to text
	cfltcvt(num, tmp, fmt, precision);

	// '#' and precision == 0 means force a decimal point
	if ((flags & SPECIAL) && precision == 0) forcdecpt(tmp);

	// 'g' format means crop zero unless '#' given
	if (fmt == 'g' && !(flags & SPECIAL)) cropzeros(tmp);

	n = strlen(tmp);

	// Output number with alignment and padding
	size -= n;
	if (!(flags & (ZEROPAD | LEFT))) while (size-- > 0) *str++ = ' ';
	if (sign) *str++ = sign;
	if (!(flags & LEFT)) while (size-- > 0) *str++ = c;
	for (i = 0; i < n; i++) *str++ = tmp[i];
	while (size-- > 0) *str++ = ' ';

	return str;
}

int vsprintf(char *buf, const char *fmt, va_list args)
{
	int len;
	unsigned long num;
	int i, base;
	char *str;
	char *s;

	int flags;            // Flags to number()

	int field_width;      // Width of output field
	int precision;        // Min. # of digits for integers; max number of chars for from string
	int qualifier;        // 'h', 'l', or 'L' for integer fields

	for (str = buf; *fmt; fmt++) {
		if (*fmt != '%') {
			*str++ = *fmt;
			continue;
			}

    // Process flags
		flags = 0;
repeat:
		fmt++; // This also skips first '%'
		switch (*fmt) {
			case '-': flags |= LEFT; goto repeat;
			case '+': flags |= PLUS; goto repeat;
			case ' ': flags |= SPACE; goto repeat;
			case '#': flags |= SPECIAL; goto repeat;
			case '0': flags |= ZEROPAD; goto repeat;
			}

    // Get field width
		field_width = -1;
		if (is_digit(*fmt)) {
			field_width = skip_atoi(&fmt);
			}
		else if (*fmt == '*') {
			fmt++;
			field_width = va_arg(args, int);
			if (field_width < 0) {
				field_width = -field_width;
				flags |= LEFT;
				}
			}

    // Get the precision
		precision = -1;
		if (*fmt == '.') {
			++fmt;
			if (is_digit(*fmt)) precision = skip_atoi(&fmt);
			else if (*fmt == '*') {
				++fmt;
				precision = va_arg(args, int);
				}
			if (precision < 0) precision = 0;
			}

    // Get the conversion qualifier
		qualifier = -1;
		if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
			qualifier = *fmt;
			fmt++;
			}

    // Default base
    base = 10;

    switch (*fmt)
    {
      case 'c':
        if (!(flags & LEFT)) while (--field_width > 0) *str++ = ' ';
        *str++ = (unsigned char) va_arg(args, int);
        while (--field_width > 0) *str++ = ' ';
        continue;

      case 's':
        s = va_arg(args, char *);
        if (s == NULL) s = "<NULL>";
        len = strnlen(s, precision);
        if (!(flags & LEFT)) while (len < field_width--) *str++ = ' ';
        for (i = 0; i < len; ++i) *str++ = *s++;
        while (len < field_width--) *str++ = ' ';
        continue;

      case 'p':
        if (field_width == -1)
        {
          field_width = 2 * sizeof(void *);
          flags |= ZEROPAD;
        }
        str = number(str, (unsigned long) va_arg(args, void *), 16, field_width, precision, flags);
        continue;

      case 'n':
        if (qualifier == 'l')
        {
          long *ip = va_arg(args, long *);
          *ip = (str - buf);
        }
        else
        {
          int *ip = va_arg(args, int *);
          *ip = (str - buf);
        }
        continue;

      case 'A':
        flags |= LARGE;

      case 'a':
        if (qualifier == 'l')
          str = eaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
        else
          str = iaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
        continue;

      // Integer number formats - set up the flags and "break"
      case 'o':
        base = 8;
        break;

      case 'X':
        flags |= LARGE;

      case 'x':
        base = 16;
        break;

      case 'd':
      case 'i':
        flags |= SIGN;

      case 'u':
        break;

      case 'E':
      case 'G':
      case 'e':
      case 'f':
      case 'g':
        str = flt(str, va_arg(args, double), field_width, precision, *fmt, flags | SIGN);
        continue;

      default:
        if (*fmt != '%') *str++ = '%';
        if (*fmt) *str++ = *fmt;
        else --fmt;
        continue;
    }

    if (qualifier == 'l')
      num = va_arg(args, unsigned long);
    else if (qualifier == 'h')
    {
      if (flags & SIGN)
        num = va_arg(args, short);
      else
        num = va_arg(args, unsigned short);
    }
    else if (flags & SIGN)
      num = va_arg(args, int);
    else
      num = va_arg(args, unsigned int);

    str = number(str, num, base, field_width, precision, flags);
  }

  *str = '\0';
  return str - buf;
}

int xprintf(char *buf, const char *fmt, ...)
{
	va_list args;
	int n;

	va_start(args, fmt);
	n = vsprintf(buf, fmt, args);

	return n;
}