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34 * From: @(#)strtol.c 8.1 (Berkeley) 6/4/93
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/ctype.h>
43 #include <sys/limits.h>
46 * Convert a string to a long integer.
48 * Ignores `locale' stuff. Assumes that the upper and lower case
49 * alphabets and digits are each contiguous.
52 strtol(const char *nptr, char **endptr, int base)
58 int neg = 0, any, cutlim;
61 * Skip white space and pick up leading +/- sign if any.
62 * If base is 0, allow 0x for hex and 0 for octal, else
63 * assume decimal; if base is already 16, allow 0x.
73 if ((base == 0 || base == 16) &&
74 c == '0' && (*s == 'x' || *s == 'X')) {
80 base = c == '0' ? 8 : 10;
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 longs is
90 * [-2147483648..2147483647] and the input base is 10,
91 * cutoff will be set to 214748364 and cutlim to either
92 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
93 * a value > 214748364, or equal but the next digit is > 7 (or 8),
94 * the number is too big, and we will return a range error.
96 * Set any if any `digits' consumed; make it negative to indicate
99 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
100 cutlim = cutoff % (unsigned long)base;
101 cutoff /= (unsigned long)base;
102 for (acc = 0, any = 0;; c = *s++) {
108 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
113 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
122 acc = neg ? LONG_MIN : LONG_MAX;
126 *endptr = __DECONST(char *, any ? s - 1 : nptr);