1 /* OPENBSD ORIGINAL: lib/libc/stdlib/strtoul.c */
4 * Copyright (c) 1990 Regents of the University of California.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
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35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char *rcsid = "$OpenBSD: strtoul.c,v 1.5 2003/06/02 20:18:38 millert Exp $";
37 #endif /* LIBC_SCCS and not lint */
45 * Convert a string to an unsigned long integer.
47 * Ignores `locale' stuff. Assumes that the upper and lower case
48 * alphabets and digits are each contiguous.
51 strtoul(nptr, endptr, base)
56 register const char *s;
57 register unsigned long acc, cutoff;
59 register int neg, any, cutlim;
62 * See strtol for comments as to the logic used.
66 c = (unsigned char) *s++;
76 if ((base == 0 || base == 16) &&
77 c == '0' && (*s == 'x' || *s == 'X')) {
83 base = c == '0' ? 8 : 10;
85 cutoff = ULONG_MAX / (unsigned long)base;
86 cutlim = ULONG_MAX % (unsigned long)base;
87 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
91 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
98 if (acc > cutoff || acc == cutoff && c > cutlim) {
104 acc *= (unsigned long)base;
111 *endptr = (char *) (any ? s - 1 : nptr);
114 #endif /* !HAVE_STRTOUL */