#include <sys/cdefs.h>
#include <limits.h>
#include <ctype.h>
#include <stdlib.h>

static int errno;


long
strtol(const char * __restrict nptr, char ** __restrict endptr, int base)
{
	const char *s;
	unsigned long acc;
	char c;
	unsigned long cutoff;
	int neg, any, cutlim;

	/*
	 * Skip white space and pick up leading +/- sign if any.
	 * If base is 0, allow 0x for hex and 0 for octal, else
	 * assume decimal; if base is already 16, allow 0x.
	 */
	s = nptr;
	do {
		c = *s++;
	} while (isspace((unsigned char)c));
	if (c == '-') {
		neg = 1;
		c = *s++;
	} else {
		neg = 0;
		if (c == '+')
			c = *s++;
	}
	if ((base == 0 || base == 16) &&
	    c == '0' && (*s == 'x' || *s == 'X')) {
		c = s[1];
		s += 2;
		base = 16;
	}
	if (base == 0)
		base = c == '0' ? 8 : 10;
	acc = any = 0;
	if (base < 2 || base > 36)
		goto noconv;

	/*
	 * Compute the cutoff value between legal numbers and illegal
	 * numbers.  That is the largest legal value, divided by the
	 * base.  An input number that is greater than this value, if
	 * followed by a legal input character, is too big.  One that
	 * is equal to this value may be valid or not; the limit
	 * between valid and invalid numbers is then based on the last
	 * digit.  For instance, if the range for longs is
	 * [-2147483648..2147483647] and the input base is 10,
	 * cutoff will be set to 214748364 and cutlim to either
	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
	 * the number is too big, and we will return a range error.
	 *
	 * Set 'any' if any `digits' consumed; make it negative to indicate
	 * overflow.
	 */
	cutoff = neg ? (unsigned long)-(LONG_MIN + LONG_MAX) + LONG_MAX
	    : LONG_MAX;
	cutlim = cutoff % base;
	cutoff /= base;
	for ( ; ; c = *s++) {
		if (c >= '0' && c <= '9')
			c -= '0';
		else if (c >= 'A' && c <= 'Z')
			c -= 'A' - 10;
		else if (c >= 'a' && c <= 'z')
			c -= 'a' - 10;
		else
			break;
		if (c >= base)
			break;
		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
			any = -1;
		else {
			any = 1;
			acc *= base;
			acc += c;
		}
	}
	if (any < 0) {
		acc = neg ? LONG_MIN : LONG_MAX;
		//errno = ERANGE;
	} else if (!any) {
noconv:
    errno = 2;
		//errno = EINVAL;
	} else if (neg)
		acc = -acc;
	if (endptr != NULL)
		*endptr = (char *)(any ? s - 1 : nptr);
	return (acc);
}