#include <lib9.h> #define ULONG_MAX	4294967295UL ulongstrtoul(char *nptr, char **endptr, int base){	char *p;	ulong n, nn, m;	int c, ovfl, neg, v, 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){		if(*p != '0')			base = 10;		else{			base = 8;			if(p[1]=='x' || p[1]=='X')				base = 16;		}	} 	if(base<2 || 36<base)		goto Return;	if(base==16 && *p=='0'){		if(p[1]=='x' || p[1]=='X')			if(('0' <= p[2] && p[2] <= '9')			 ||('a' <= p[2] && p[2] <= 'f')			 ||('A' <= p[2] && p[2] <= 'F'))				p += 2;	}	/*	 * Non-empty sequence of digits	 */	n = 0;	m = ULONG_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 = nptr;	if(endptr)		*endptr = p;	if(ovfl)		return ULONG_MAX;	if(neg)		return -n;	return n;}