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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
;