efi/printf: Factor out width/precision parsing

	} while (1);

}

int vsprintf(char *buf, const char *fmt, va_list args)

static

int get_int(const char **fmt, va_list *ap)

{

	if (isdigit(**fmt))

		return skip_atoi(fmt);

	if (**fmt == '*') {

		++(*fmt);

		/* it's the next argument */

		return va_arg(*ap, int);

	}

	return 0;

}

int vsprintf(char *buf, const char *fmt, va_list ap)

{

	int len;

	unsigned long long num;

				   number of chars for from string */

	int qualifier;		/* 'h', 'hh', 'l' or 'll' for integer fields */

	va_list args;

	/*

	 * We want to pass our input va_list to helper functions by reference,

	 * but there's an annoying edge case. If va_list was originally passed

	 * to us by value, we could just pass &ap down to the helpers. This is

	 * the case on, for example, X86_32.

	 * However, on X86_64 (and possibly others), va_list is actually a

	 * size-1 array containing a structure. Our function parameter ap has

	 * decayed from T[1] to T*, and &ap has type T** rather than T(*)[1],

	 * which is what will be expected by a function taking a va_list *

	 * parameter.

	 * One standard way to solve this mess is by creating a copy in a local

	 * variable of type va_list and then passing a pointer to that local

	 * copy instead, which is what we do here.

	 */

	va_copy(args, ap);

	for (str = buf; *fmt; ++fmt) {

		if (*fmt != '%' || *++fmt == '%') {

			*str++ = *fmt;

		flags = get_flags(&fmt);

		/* get field width */

		field_width = -1;

		if (isdigit(*fmt)) {

			field_width = skip_atoi(&fmt);

		} else if (*fmt == '*') {

			++fmt;

			/* it's the next argument */

			field_width = va_arg(args, int);

		field_width = get_int(&fmt, &args);

		if (field_width < 0) {

			field_width = -field_width;

			flags |= LEFT;

		}

		}

		/* get the precision */

		precision = -1;

		if (*fmt == '.') {

			++fmt;

			if (isdigit(*fmt)) {

				precision = skip_atoi(&fmt);

			} else if (*fmt == '*') {

				++fmt;

				/* it's the next argument */

				precision = va_arg(args, int);

			} else {

				precision = 0;

			}

			precision = get_int(&fmt, &args);

			if (precision >= 0)

				flags &= ~ZEROPAD;

		}

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

	}

	*str = '\0';

	va_end(args);

	return str - buf;

}