1/* $OpenBSD: strtoll.c,v 1.6 2005/11/10 10:00:17 espie 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/* OPENBSD ORIGINAL: lib/libc/stdlib/strtoll.c */
32
33#include "includes.h"
34#ifndef HAVE_STRTOLL
35
36#include <sys/types.h>
37
38#include <ctype.h>
39#include <errno.h>
40#include <limits.h>
41#include <stdlib.h>
42
43/*
44 * Convert a string to a long long.
45 *
46 * Ignores `locale' stuff.  Assumes that the upper and lower case
47 * alphabets and digits are each contiguous.
48 */
49long long
50strtoll(const char *nptr, char **endptr, int base)
51{
52	const char *s;
53	long long acc, cutoff;
54	int c;
55	int neg, any, cutlim;
56
57	/*
58	 * Skip white space and pick up leading +/- sign if any.
59	 * If base is 0, allow 0x for hex and 0 for octal, else
60	 * assume decimal; if base is already 16, allow 0x.
61	 */
62	s = nptr;
63	do {
64		c = (unsigned char) *s++;
65	} while (isspace(c));
66	if (c == '-') {
67		neg = 1;
68		c = *s++;
69	} else {
70		neg = 0;
71		if (c == '+')
72			c = *s++;
73	}
74	if ((base == 0 || base == 16) &&
75	    c == '0' && (*s == 'x' || *s == 'X')) {
76		c = s[1];
77		s += 2;
78		base = 16;
79	}
80	if (base == 0)
81		base = c == '0' ? 8 : 10;
82
83	/*
84	 * Compute the cutoff value between legal numbers and illegal
85	 * numbers.  That is the largest legal value, divided by the
86	 * base.  An input number that is greater than this value, if
87	 * followed by a legal input character, is too big.  One that
88	 * is equal to this value may be valid or not; the limit
89	 * between valid and invalid numbers is then based on the last
90	 * digit.  For instance, if the range for long longs is
91	 * [-9223372036854775808..9223372036854775807] and the input base
92	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
93	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
94	 * accumulated a value > 922337203685477580, or equal but the
95	 * next digit is > 7 (or 8), the number is too big, and we will
96	 * return a range error.
97	 *
98	 * Set any if any `digits' consumed; make it negative to indicate
99	 * overflow.
100	 */
101	cutoff = neg ? LLONG_MIN : LLONG_MAX;
102	cutlim = cutoff % base;
103	cutoff /= base;
104	if (neg) {
105		if (cutlim > 0) {
106			cutlim -= base;
107			cutoff += 1;
108		}
109		cutlim = -cutlim;
110	}
111	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
112		if (isdigit(c))
113			c -= '0';
114		else if (isalpha(c))
115			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
116		else
117			break;
118		if (c >= base)
119			break;
120		if (any < 0)
121			continue;
122		if (neg) {
123			if (acc < cutoff || (acc == cutoff && c > cutlim)) {
124				any = -1;
125				acc = LLONG_MIN;
126				errno = ERANGE;
127			} else {
128				any = 1;
129				acc *= base;
130				acc -= c;
131			}
132		} else {
133			if (acc > cutoff || (acc == cutoff && c > cutlim)) {
134				any = -1;
135				acc = LLONG_MAX;
136				errno = ERANGE;
137			} else {
138				any = 1;
139				acc *= base;
140				acc += c;
141			}
142		}
143	}
144	if (endptr != 0)
145		*endptr = (char *) (any ? s - 1 : nptr);
146	return (acc);
147}
148#endif /* HAVE_STRTOLL */
149