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32 * $FreeBSD: src/sys/libkern/strtoq.c,v 1.3 1999/12/01 22:56:51 archie Exp $
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/ctype.h>
38 #include <machine/limits.h>
41 * Convert a string to a quad integer.
43 * Ignores `locale' stuff. Assumes that the upper and lower case
44 * alphabets and digits are each contiguous.
47 strtoq(const char *nptr, char **endptr, int base)
52 u_quad_t qbase, cutoff;
56 * Skip white space and pick up leading +/- sign if any.
57 * If base is 0, allow 0x for hex and 0 for octal, else
58 * assume decimal; if base is already 16, allow 0x.
72 if ((base == 0 || base == 16) &&
73 c == '0' && (*s == 'x' || *s == 'X')) {
79 base = c == '0' ? 8 : 10;
82 * Compute the cutoff value between legal numbers and illegal
83 * numbers. That is the largest legal value, divided by the
84 * base. An input number that is greater than this value, if
85 * followed by a legal input character, is too big. One that
86 * is equal to this value may be valid or not; the limit
87 * between valid and invalid numbers is then based on the last
88 * digit. For instance, if the range for quads is
89 * [-9223372036854775808..9223372036854775807] and the input base
90 * is 10, cutoff will be set to 922337203685477580 and cutlim to
91 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
92 * accumulated a value > 922337203685477580, or equal but the
93 * next digit is > 7 (or 8), the number is too big, and we will
94 * return a range error.
96 * Set any if any `digits' consumed; make it negative to indicate
99 qbase = (unsigned)base;
100 cutoff = neg ? (u_quad_t)-(QUAD_MIN + QUAD_MAX) + QUAD_MAX : QUAD_MAX;
101 cutlim = cutoff % qbase;
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 ? QUAD_MIN : QUAD_MAX;
127 *((const char **)(void *)endptr) = any ? s - 1 : nptr;