xref: /freebsd/sys/libkern/strtoul.c (revision 4a8dea8cf97aab33f4e6a11afcc64dd9562f3bfd)
11a4e73baSPoul-Henning Kamp /*-
21a4e73baSPoul-Henning Kamp  * Copyright (c) 1990, 1993
31a4e73baSPoul-Henning Kamp  *	The Regents of the University of California.  All rights reserved.
41a4e73baSPoul-Henning Kamp  *
51a4e73baSPoul-Henning Kamp  * This code is derived from software contributed to Berkeley by
61a4e73baSPoul-Henning Kamp  * Chris Torek.
71a4e73baSPoul-Henning Kamp  *
81a4e73baSPoul-Henning Kamp  * Redistribution and use in source and binary forms, with or without
91a4e73baSPoul-Henning Kamp  * modification, are permitted provided that the following conditions
101a4e73baSPoul-Henning Kamp  * are met:
111a4e73baSPoul-Henning Kamp  * 1. Redistributions of source code must retain the above copyright
121a4e73baSPoul-Henning Kamp  *    notice, this list of conditions and the following disclaimer.
131a4e73baSPoul-Henning Kamp  * 2. Redistributions in binary form must reproduce the above copyright
141a4e73baSPoul-Henning Kamp  *    notice, this list of conditions and the following disclaimer in the
151a4e73baSPoul-Henning Kamp  *    documentation and/or other materials provided with the distribution.
16fbbd9655SWarner Losh  * 3. Neither the name of the University nor the names of its contributors
171a4e73baSPoul-Henning Kamp  *    may be used to endorse or promote products derived from this software
181a4e73baSPoul-Henning Kamp  *    without specific prior written permission.
191a4e73baSPoul-Henning Kamp  *
201a4e73baSPoul-Henning Kamp  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
211a4e73baSPoul-Henning Kamp  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
221a4e73baSPoul-Henning Kamp  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
231a4e73baSPoul-Henning Kamp  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
241a4e73baSPoul-Henning Kamp  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
251a4e73baSPoul-Henning Kamp  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
261a4e73baSPoul-Henning Kamp  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
271a4e73baSPoul-Henning Kamp  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
281a4e73baSPoul-Henning Kamp  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
291a4e73baSPoul-Henning Kamp  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
301a4e73baSPoul-Henning Kamp  * SUCH DAMAGE.
311a4e73baSPoul-Henning Kamp  *
32ab0de15bSDavid E. O'Brien  * From: @(#)strtoul.c	8.1 (Berkeley) 6/4/93
331a4e73baSPoul-Henning Kamp  */
341a4e73baSPoul-Henning Kamp 
35ab0de15bSDavid E. O'Brien #include <sys/cdefs.h>
36ab0de15bSDavid E. O'Brien __FBSDID("$FreeBSD$");
37ab0de15bSDavid E. O'Brien 
381a4e73baSPoul-Henning Kamp #include <sys/param.h>
391a4e73baSPoul-Henning Kamp #include <sys/systm.h>
401a4e73baSPoul-Henning Kamp #include <sys/ctype.h>
41104a9b7eSAlexander Kabaev #include <sys/limits.h>
421a4e73baSPoul-Henning Kamp 
431a4e73baSPoul-Henning Kamp /*
441a4e73baSPoul-Henning Kamp  * Convert a string to an unsigned long integer.
451a4e73baSPoul-Henning Kamp  *
461a4e73baSPoul-Henning Kamp  * Ignores `locale' stuff.  Assumes that the upper and lower case
471a4e73baSPoul-Henning Kamp  * alphabets and digits are each contiguous.
481a4e73baSPoul-Henning Kamp  */
491a4e73baSPoul-Henning Kamp unsigned long
50*4a8dea8cSEd Maste strtoul(const char *nptr, char **endptr, int base)
511a4e73baSPoul-Henning Kamp {
521a4e73baSPoul-Henning Kamp 	const char *s = nptr;
531a4e73baSPoul-Henning Kamp 	unsigned long acc;
541a4e73baSPoul-Henning Kamp 	unsigned char c;
551a4e73baSPoul-Henning Kamp 	unsigned long cutoff;
561a4e73baSPoul-Henning Kamp 	int neg = 0, any, cutlim;
571a4e73baSPoul-Henning Kamp 
581a4e73baSPoul-Henning Kamp 	/*
591a4e73baSPoul-Henning Kamp 	 * See strtol for comments as to the logic used.
601a4e73baSPoul-Henning Kamp 	 */
611a4e73baSPoul-Henning Kamp 	do {
621a4e73baSPoul-Henning Kamp 		c = *s++;
631a4e73baSPoul-Henning Kamp 	} while (isspace(c));
641a4e73baSPoul-Henning Kamp 	if (c == '-') {
651a4e73baSPoul-Henning Kamp 		neg = 1;
661a4e73baSPoul-Henning Kamp 		c = *s++;
671a4e73baSPoul-Henning Kamp 	} else if (c == '+')
681a4e73baSPoul-Henning Kamp 		c = *s++;
691a4e73baSPoul-Henning Kamp 	if ((base == 0 || base == 16) &&
701a4e73baSPoul-Henning Kamp 	    c == '0' && (*s == 'x' || *s == 'X')) {
711a4e73baSPoul-Henning Kamp 		c = s[1];
721a4e73baSPoul-Henning Kamp 		s += 2;
731a4e73baSPoul-Henning Kamp 		base = 16;
741a4e73baSPoul-Henning Kamp 	}
751a4e73baSPoul-Henning Kamp 	if (base == 0)
761a4e73baSPoul-Henning Kamp 		base = c == '0' ? 8 : 10;
771a4e73baSPoul-Henning Kamp 	cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
781a4e73baSPoul-Henning Kamp 	cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
791a4e73baSPoul-Henning Kamp 	for (acc = 0, any = 0;; c = *s++) {
801a4e73baSPoul-Henning Kamp 		if (!isascii(c))
811a4e73baSPoul-Henning Kamp 			break;
821a4e73baSPoul-Henning Kamp 		if (isdigit(c))
831a4e73baSPoul-Henning Kamp 			c -= '0';
841a4e73baSPoul-Henning Kamp 		else if (isalpha(c))
851a4e73baSPoul-Henning Kamp 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
861a4e73baSPoul-Henning Kamp 		else
871a4e73baSPoul-Henning Kamp 			break;
881a4e73baSPoul-Henning Kamp 		if (c >= base)
891a4e73baSPoul-Henning Kamp 			break;
901a4e73baSPoul-Henning Kamp 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
911a4e73baSPoul-Henning Kamp 			any = -1;
921a4e73baSPoul-Henning Kamp 		else {
931a4e73baSPoul-Henning Kamp 			any = 1;
941a4e73baSPoul-Henning Kamp 			acc *= base;
951a4e73baSPoul-Henning Kamp 			acc += c;
961a4e73baSPoul-Henning Kamp 		}
971a4e73baSPoul-Henning Kamp 	}
981a4e73baSPoul-Henning Kamp 	if (any < 0) {
991a4e73baSPoul-Henning Kamp 		acc = ULONG_MAX;
1001a4e73baSPoul-Henning Kamp 	} else if (neg)
1011a4e73baSPoul-Henning Kamp 		acc = -acc;
102b85f65afSPedro F. Giffuni 	if (endptr != NULL)
1030b77a417SDimitry Andric 		*endptr = __DECONST(char *, any ? s - 1 : nptr);
1041a4e73baSPoul-Henning Kamp 	return (acc);
1051a4e73baSPoul-Henning Kamp }
106