/*-

 * Copyright (c) 1992, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <limits.h>

#include <errno.h>

#include <ctype.h>

#include <stdlib.h>

/*

 * Convert a string to an unsigned long long integer.

 *

 * Assumes that the upper and lower case

 * alphabets and digits are each contiguous.

 */

unsigned long long

strtoull(const char *nptr, char **endptr, int base)

{

	const char *s;

	unsigned long long acc;

	char c;

	unsigned long long cutoff;

	int neg, any, cutlim;

	/*

	 * See strtoq for comments as to the logic used.

	 */

	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') &&

	    ((s[1] >= '0' && s[1] <= '9') ||

	    (s[1] >= 'A' && s[1] <= 'F') ||

	    (s[1] >= 'a' && s[1] <= 'f'))) {

		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;

	cutoff = ULLONG_MAX / base;

	cutlim = ULLONG_MAX % 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 = ULLONG_MAX;

		errno = ERANGE;

	} else if (!any) {

noconv:

		errno = EINVAL;

	} else if (neg)

		acc = -acc;

	if (endptr != NULL)

		*endptr = (char *)(any ? s - 1 : nptr);

	return (acc);

}