1/* $OpenBSD: strtoll.c,v 1.7 2013/03/28 18:09:38 martynas Exp $ */
2/*-
3 * Copyright (c) 1992 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/types.h>
32
33#include <ctype.h>
34#include <errno.h>
35#include <limits.h>
36#include <stdlib.h>
37
38/*
39 * Convert a string to a long long.
40 *
41 * Ignores `locale' stuff.  Assumes that the upper and lower case
42 * alphabets and digits are each contiguous.
43 */
44long long
45strtoll(const char *nptr, char **endptr, int base)
46{
47	const char *s;
48	long long acc, cutoff;
49	int c;
50	int neg, any, cutlim;
51
52	/*
53	 * Skip white space and pick up leading +/- sign if any.
54	 * If base is 0, allow 0x for hex and 0 for octal, else
55	 * assume decimal; if base is already 16, allow 0x.
56	 */
57	s = nptr;
58	do {
59		c = (unsigned char) *s++;
60	} while (isspace(c));
61	if (c == '-') {
62		neg = 1;
63		c = *s++;
64	} else {
65		neg = 0;
66		if (c == '+')
67			c = *s++;
68	}
69	if ((base == 0 || base == 16) &&
70	    c == '0' && (*s == 'x' || *s == 'X')) {
71		c = s[1];
72		s += 2;
73		base = 16;
74	}
75	if (base == 0)
76		base = c == '0' ? 8 : 10;
77
78	/*
79	 * Compute the cutoff value between legal numbers and illegal
80	 * numbers.  That is the largest legal value, divided by the
81	 * base.  An input number that is greater than this value, if
82	 * followed by a legal input character, is too big.  One that
83	 * is equal to this value may be valid or not; the limit
84	 * between valid and invalid numbers is then based on the last
85	 * digit.  For instance, if the range for long longs is
86	 * [-9223372036854775808..9223372036854775807] and the input base
87	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
88	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
89	 * accumulated a value > 922337203685477580, or equal but the
90	 * next digit is > 7 (or 8), the number is too big, and we will
91	 * return a range error.
92	 *
93	 * Set any if any `digits' consumed; make it negative to indicate
94	 * overflow.
95	 */
96	cutoff = neg ? LLONG_MIN : LLONG_MAX;
97	cutlim = cutoff % base;
98	cutoff /= base;
99	if (neg) {
100		if (cutlim > 0) {
101			cutlim -= base;
102			cutoff += 1;
103		}
104		cutlim = -cutlim;
105	}
106	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
107		if (isdigit(c))
108			c -= '0';
109		else if (isalpha(c))
110			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
111		else
112			break;
113		if (c >= base)
114			break;
115		if (any < 0)
116			continue;
117		if (neg) {
118			if (acc < cutoff || (acc == cutoff && c > cutlim)) {
119				any = -1;
120				acc = LLONG_MIN;
121				errno = ERANGE;
122			} else {
123				any = 1;
124				acc *= base;
125				acc -= c;
126			}
127		} else {
128			if (acc > cutoff || (acc == cutoff && c > cutlim)) {
129				any = -1;
130				acc = LLONG_MAX;
131				errno = ERANGE;
132			} else {
133				any = 1;
134				acc *= base;
135				acc += c;
136			}
137		}
138	}
139	if (endptr != 0)
140		*endptr = (char *) (any ? s - 1 : nptr);
141	return (acc);
142}
143
144__strong_alias(strtoq, strtoll);
145