2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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9 * modification, are permitted provided that the following conditions
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18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
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21 * may be used to endorse or promote products derived from this software
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24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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36 * From: static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93";
38 * $FreeBSD: src/sys/libkern/strtol.c,v 1.5 1999/12/01 22:56:50 archie Exp $
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/ctype.h>
44 #include <machine/limits.h>
47 * Convert a string to a long integer.
49 * Ignores `locale' stuff. Assumes that the upper and lower case
50 * alphabets and digits are each contiguous.
53 strtol(const char *nptr, char **endptr, int base)
59 int neg = 0, any, cutlim;
62 * Skip white space and pick up leading +/- sign if any.
63 * If base is 0, allow 0x for hex and 0 for octal, else
64 * assume decimal; if base is already 16, allow 0x.
74 if ((base == 0 || base == 16) &&
75 c == '0' && (*s == 'x' || *s == 'X')) {
81 base = c == '0' ? 8 : 10;
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 longs is
91 * [-2147483648..2147483647] and the input base is 10,
92 * cutoff will be set to 214748364 and cutlim to either
93 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
94 * a value > 214748364, or equal but the next digit is > 7 (or 8),
95 * the number is too big, and we will return a range error.
97 * Set any if any `digits' consumed; make it negative to indicate
100 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
101 cutlim = cutoff % (unsigned long)base;
102 cutoff /= (unsigned long)base;
103 for (acc = 0, any = 0;; c = *s++) {
109 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
114 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
123 acc = neg ? LONG_MIN : LONG_MAX;
127 *((const char **)(void *)endptr) = any ? s - 1 : nptr;