#include <u.h>#include <libc.h>#define VLONG_MAX	((vlong)~(((uvlong)1)<<63))#define VLONG_MIN	((vlong)(((uvlong)1)<<63))vlongstrtoll(const char *nptr, char **endptr, int base){	char *p;	vlong n, nn, m;	int c, ovfl, v, neg, ndig;	p = (char*)nptr;	neg = 0;	n = 0;	ndig = 0;	ovfl = 0;	/*	 * White space	 */	for(;; p++) {		switch(*p) {		case ' ':		case '\t':		case '\n':		case '\f':		case '\r':		case '\v':			continue;		}		break;	}	/*	 * Sign	 */	if(*p=='-' || *p=='+')		if(*p++ == '-')			neg = 1;	/*	 * Base	 */	if(base==0){		base = 10;		if(*p == '0') {			base = 8;			if(p[1]=='x' || p[1]=='X') {				p += 2;				base = 16;			}		}	} else	if(base==16 && *p=='0') {		if(p[1]=='x' || p[1]=='X')			p += 2;	} else	if(base<0 || 36<base)		goto Return;	/*	 * Non-empty sequence of digits	 */	m = VLONG_MAX/base;	for(;; p++,ndig++) {		c = *p;		v = base;		if('0'<=c && c<='9')			v = c - '0';		else		if('a'<=c && c<='z')			v = c - 'a' + 10;		else		if('A'<=c && c<='Z')			v = c - 'A' + 10;		if(v >= base)			break;		if(n > m)			ovfl = 1;		nn = n*base + v;		if(nn < n)			ovfl = 1;		n = nn;	}Return:	if(ndig == 0)		p = (char*)nptr;	if(endptr)		*endptr = p;	if(ovfl){		if(neg)			return VLONG_MIN;		return VLONG_MAX;	}	if(neg)		return -n;	return n;}