Function strtoull

payloads/libpayload/libc/string.c:408–450

 */

unsigned long long int strtoull(const char *ptr, char **endptr, int base)
{
	unsigned long long int ret = 0;

	if (endptr != NULL)
		*endptr = (char *) ptr;

	/* Purge whitespace */

	for ( ; *ptr && isspace(*ptr); ptr++);

	if (!*ptr)
		return 0;

	/* Determine the base */

	if (base == 0) {
		if (ptr[0] == '0' && (ptr[1] == 'x' || ptr[1] == 'X'))
			base = 16;
		else if (ptr[0] == '0') {
			base = 8;
			ptr++;
		} else {
			base = 10;
		}
	}

	/* Base 16 allows the 0x on front - so skip over it */

	if (base == 16) {
		if (ptr[0] == '0' && (ptr[1] == 'x' || ptr[1] == 'X') &&
		    _valid(ptr[2], base))
			ptr += 2;
	}

	for ( ; *ptr && _valid(*ptr, base); ptr++)
		ret = (ret * base) + _offset(*ptr, base);

	if (endptr != NULL)
		*endptr = (char *) ptr;

	return ret;
}

unsigned long int strtoul(const char *ptr, char **endptr, int base)
{