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| author | des <des@FreeBSD.org> | 2010-08-15 14:55:32 +0000 |
|---|---|---|
| committer | des <des@FreeBSD.org> | 2010-08-15 14:55:32 +0000 |
| commit | 1c0c0dee6b06dc1b3dfbf19e2a05bcd2ad7751c9 (patch) | |
| tree | 2df0914821a027f90d0fb465de23796faf70a3c0 /lib | |
| parent | 19384270153e149e4f9311215e1b718796d9939d (diff) | |
| download | FreeBSD-src-1c0c0dee6b06dc1b3dfbf19e2a05bcd2ad7751c9.zip FreeBSD-src-1c0c0dee6b06dc1b3dfbf19e2a05bcd2ad7751c9.tar.gz | |
no-op commit to note that the example given in the previous commit is
a very bad one, since the shift does not actually overflow. This is
a better example (assuming uint64_t = unsigned long long):
~0LLU >> 9 = 0x7fffffffffffffLLU
~0LLU >> 9 << 10 = 0xfffffffffffffc00LLU
~0LLU >> 9 << 10 >> 10 = 0x3fffffffffffffLLU
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/libutil/expand_number.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/libutil/expand_number.c b/lib/libutil/expand_number.c index 9bb0308..30a292e 100644 --- a/lib/libutil/expand_number.c +++ b/lib/libutil/expand_number.c @@ -66,7 +66,7 @@ expand_number(const char *buf, uint64_t *num) return (0); } -#define SHIFT(n, b) \ +#define SHIFT(n, b) \ do { if (((n << b) >> b) != n) goto overflow; n <<= b; } while (0) switch (tolower((unsigned char)*endptr)) { |
