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33 * @(#)strtol.c 8.1 (Berkeley) 6/4/93
34 * $DragonFly: src/lib/libstand/strtol.c,v 1.3 2004/10/25 19:38:45 drhodus Exp $
41 * Convert a string to a long integer.
43 * Ignores `locale' stuff. Assumes that the upper and lower case
44 * alphabets and digits are each contiguous.
47 strtol(nptr, endptr, base)
56 int neg = 0, any, cutlim;
58 /* Be sensible about NULL strings */
64 * Skip white space and pick up leading +/- sign if any.
65 * If base is 0, allow 0x for hex and 0 for octal, else
66 * assume decimal; if base is already 16, allow 0x.
76 if ((base == 0 || base == 16) &&
77 c == '0' && (*s == 'x' || *s == 'X')) {
83 base = c == '0' ? 8 : 10;
86 * Compute the cutoff value between legal numbers and illegal
87 * numbers. That is the largest legal value, divided by the
88 * base. An input number that is greater than this value, if
89 * followed by a legal input character, is too big. One that
90 * is equal to this value may be valid or not; the limit
91 * between valid and invalid numbers is then based on the last
92 * digit. For instance, if the range for longs is
93 * [-2147483648..2147483647] and the input base is 10,
94 * cutoff will be set to 214748364 and cutlim to either
95 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
96 * a value > 214748364, or equal but the next digit is > 7 (or 8),
97 * the number is too big, and we will return a range error.
99 * Set any if any `digits' consumed; make it negative to indicate
102 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
103 cutlim = cutoff % (unsigned long)base;
104 cutoff /= (unsigned long)base;
105 for (acc = 0, any = 0;; c = *s++) {
111 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
116 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
125 acc = neg ? LONG_MIN : LONG_MAX;
130 *endptr = (char *)(any ? s - 1 : nptr);