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| author | Dag-Erling Smørgrav <des@FreeBSD.org> | 2010-08-15 14:55:32 +0000 |
|---|---|---|
| committer | Dag-Erling Smørgrav <des@FreeBSD.org> | 2010-08-15 14:55:32 +0000 |
| commit | b6fbd4d50dd30e90231bb0b2f8ddf9fd96691b39 (patch) | |
| tree | 2df0914821a027f90d0fb465de23796faf70a3c0 /lib/libutil/expand_number.c | |
| parent | 1035d74025de93515f0a7baf2c48eed25e854099 (diff) | |
| download | src-b6fbd4d50dd30e90231bb0b2f8ddf9fd96691b39.tar.gz src-b6fbd4d50dd30e90231bb0b2f8ddf9fd96691b39.zip | |
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
Notes
Notes:
svn path=/head/; revision=211338
Diffstat (limited to 'lib/libutil/expand_number.c')
| -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 9bb0308d1415..30a292ef64c2 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)) { |