/*      $OpenBSD: strtoull.c,v 1.9 2017/07/06 16:23:11 millert Exp $ */
/*
 * Copyright (c) 1992 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. 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 <sys/types.h>

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>

/*
 * Convert a string to an unsigned long long.
 *
 * Ignores `locale' stuff.  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, cutoff;
        int c;
        int neg, any, cutlim;

        /*
         * See strtoll for comments as to the logic used.
         */
        if (base < 0 || base == 1 || base > 36) {
                if (endptr != 0)
                        *endptr = (char *)nptr;
                errno = EINVAL;
                return 0;
        }

        s = nptr;
        do {
                c = (unsigned char) *s++;
        } while (isspace(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') && isxdigit((unsigned char)s[1])) {
                c = s[1];
                s += 2;
                base = 16;
        }
        if (base == 0)
                base = c == '0' ? 8 : 10;

        cutoff = ULLONG_MAX / (unsigned long long)base;
        cutlim = ULLONG_MAX % (unsigned long long)base;
        for (acc = 0, any = 0;; c = (unsigned char) *s++) {
                if (isdigit(c))
                        c -= '0';
                else if (isalpha(c))
                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                else
                        break;
                if (c >= base)
                        break;
                if (any < 0)
                        continue;
                if (acc > cutoff || (acc == cutoff && c > cutlim)) {
                        any = -1;
                        acc = ULLONG_MAX;
                        errno = ERANGE;
                } else {
                        any = 1;
                        acc *= (unsigned long long)base;
                        acc += c;
                }
        }
        if (neg && any > 0)
                acc = -acc;
        if (endptr != 0)
                *endptr = (char *) (any ? s - 1 : nptr);
        return (acc);
}
DEF_STRONG(strtoull);

__weak_alias(strtouq, strtoull);