1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/ctype.h>
39#include <sys/limits.h>
40
41/*
42 * Convert a string to a quad integer.
43 *
44 * Ignores `locale' stuff.  Assumes that the upper and lower case
45 * alphabets and digits are each contiguous.
46 */
47quad_t
48strtoq(const char *nptr, char **endptr, int base)
49{
50	const char *s;
51	u_quad_t acc;
52	unsigned char c;
53	u_quad_t qbase, cutoff;
54	int neg, any, cutlim;
55
56	/*
57	 * Skip white space and pick up leading +/- sign if any.
58	 * If base is 0, allow 0x for hex and 0 for octal, else
59	 * assume decimal; if base is already 16, allow 0x.
60	 */
61	s = nptr;
62	do {
63		c = *s++;
64	} while (isspace(c));
65	if (c == '-') {
66		neg = 1;
67		c = *s++;
68	} else {
69		neg = 0;
70		if (c == '+')
71			c = *s++;
72	}
73	if ((base == 0 || base == 16) &&
74	    c == '0' && (*s == 'x' || *s == 'X')) {
75		c = s[1];
76		s += 2;
77		base = 16;
78	}
79	if (base == 0)
80		base = c == '0' ? 8 : 10;
81
82	/*
83	 * Compute the cutoff value between legal numbers and illegal
84	 * numbers.  That is the largest legal value, divided by the
85	 * base.  An input number that is greater than this value, if
86	 * followed by a legal input character, is too big.  One that
87	 * is equal to this value may be valid or not; the limit
88	 * between valid and invalid numbers is then based on the last
89	 * digit.  For instance, if the range for quads is
90	 * [-9223372036854775808..9223372036854775807] and the input base
91	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
92	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
93	 * accumulated a value > 922337203685477580, or equal but the
94	 * next digit is > 7 (or 8), the number is too big, and we will
95	 * return a range error.
96	 *
97	 * Set any if any `digits' consumed; make it negative to indicate
98	 * overflow.
99	 */
100	qbase = (unsigned)base;
101	cutoff = neg ? (u_quad_t)-(QUAD_MIN + QUAD_MAX) + QUAD_MAX : QUAD_MAX;
102	cutlim = cutoff % qbase;
103	cutoff /= qbase;
104	for (acc = 0, any = 0;; c = *s++) {
105		if (!isascii(c))
106			break;
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 || acc > cutoff || (acc == cutoff && c > cutlim))
116			any = -1;
117		else {
118			any = 1;
119			acc *= qbase;
120			acc += c;
121		}
122	}
123	if (any < 0) {
124		acc = neg ? QUAD_MIN : QUAD_MAX;
125	} else if (neg)
126		acc = -acc;
127	if (endptr != 0)
128		*((const char **)endptr) = any ? s - 1 : nptr;
129	return (acc);
130}
131