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| author | Jonathan Nieder <jrnieder@gmail.com> | 2010-10-10 21:59:26 -0500 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2011-02-10 13:47:56 -0800 |
| commit | 1368f65002bf39fdde7dd736a75ae35475184371 (patch) | |
| tree | cb0d57165c5b1f710bb5e6499fa322185a8deb2f /patch-delta.c | |
| parent | a8e4a5943a63c8fd4a3a9b70ccf4608bcc973707 (diff) | |
| download | git-1368f65002bf39fdde7dd736a75ae35475184371.tar.gz | |
compat: helper for detecting unsigned overflow
The idiom (a + b < a) works fine for detecting that an unsigned
integer has overflowed, but a more explicit
unsigned_add_overflows(a, b)
might be easier to read.
Define such a macro, expanding roughly to ((a) < UINT_MAX - (b)).
Because the expansion uses each argument only once outside of sizeof()
expressions, it is safe to use with arguments that have side effects.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'patch-delta.c')
| -rw-r--r-- | patch-delta.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/patch-delta.c b/patch-delta.c index d218faa02b..56e0a5ede2 100644 --- a/patch-delta.c +++ b/patch-delta.c @@ -48,7 +48,7 @@ void *patch_delta(const void *src_buf, unsigned long src_size, if (cmd & 0x20) cp_size |= (*data++ << 8); if (cmd & 0x40) cp_size |= (*data++ << 16); if (cp_size == 0) cp_size = 0x10000; - if (cp_off + cp_size < cp_size || + if (unsigned_add_overflows(cp_off, cp_size) || cp_off + cp_size > src_size || cp_size > size) break; |