1/*	$OpenBSD: strtoumax.c,v 1.1 2006/01/13 17:58:09 millert Exp $	*/
2
3/*-
4 * Copyright (c) 1992 The Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <ctype.h>
33#include <errno.h>
34#include <inttypes.h>
35
36/*
37 * Convert a string to a uintmax_t.
38 *
39 * Ignores `locale' stuff.  Assumes that the upper and lower case
40 * alphabets and digits are each contiguous.
41 */
42uintmax_t
43strtoumax(const char *nptr, char **endptr, int base)
44{
45	const char *s;
46	uintmax_t acc, cutoff;
47	int c;
48	int neg, any, cutlim;
49
50	/*
51	 * See strtoq for comments as to the logic used.
52	 */
53	s = nptr;
54	do {
55		c = (unsigned char) *s++;
56	} while (isspace(c));
57	if (c == '-') {
58		neg = 1;
59		c = *s++;
60	} else {
61		neg = 0;
62		if (c == '+')
63			c = *s++;
64	}
65	if ((base == 0 || base == 16) &&
66	    c == '0' && (*s == 'x' || *s == 'X')) {
67		c = s[1];
68		s += 2;
69		base = 16;
70	}
71	if (base == 0)
72		base = c == '0' ? 8 : 10;
73
74        /* BIONIC: avoid division and modulo for common cases */
75#define  CASE_BASE(x)                            \
76            case x: cutoff = UINTMAX_MAX / x;    \
77	            cutlim = UINTMAX_MAX % x;    \
78		    break
79
80        switch (base) {
81        CASE_BASE(8);
82	CASE_BASE(10);
83	CASE_BASE(16);
84	default:
85	    cutoff = UINTMAX_MAX / base;
86	    cutlim = UINTMAX_MAX % base;
87	}
88
89	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
90		if (isdigit(c))
91			c -= '0';
92		else if (isalpha(c))
93			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
94		else
95			break;
96		if (c >= base)
97			break;
98		if (any < 0)
99			continue;
100		if (acc > cutoff || (acc == cutoff && c > cutlim)) {
101			any = -1;
102			acc = UINTMAX_MAX;
103			errno = ERANGE;
104		} else {
105			any = 1;
106			acc *= (uintmax_t)base;
107			acc += c;
108		}
109	}
110	if (neg && any > 0)
111		acc = -acc;
112	if (endptr != 0)
113		*endptr = (char *) (any ? s - 1 : nptr);
114	return (acc);
115}
116