Fix a comparison bug in diff-delta.c

(1 << i) < hspace is compared in the int space rather that in the unsigned one. the result will be wrong if hspace is between 0x40000000 and 0x80000000.

---

I'm currently trying to make git compile with more strict gcc flags
(-g -O2 -Wall -Wextra -Wno-unused -Werror to be precise) and I've spotted a first bug due to a signed/unsigned comparison.

If I do understand that bit of code, it should not bite a lot of
people, but this is still a bug ;)

 diff-delta.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 7da9205..a1fadc9 100644
@@ -152,7 +152,7 @@ struct delta_index * create_delta_index(
 	   initialization in create_delta(). */
 	entries = (bufsize - 1)  / RABIN_WINDOW;
 	hsize = entries / 4;
-	for (i = 4; (1 << i) < hsize && i < 31; i++);
+	for (i = 4; (unsigned)(1 << i) < hsize && i < 31; i++);
 	hsize = 1 << i;
 	hmask = hsize - 1;
 

1.4.1.1

still in the same kind of "problems" sha1_name.c:512 has:

		if (active_nr < 0)
			return -1;

but active_nr is defined as an unsigned (in cache.h/cache-read.c).

Also note that there is a *lot* of signed/unsigned comparisons due to the fact that it's unsigned, and that it's often compared to positions that are ints (I assume pos need the negative values to mean "error").

so either those two lines are too much, or active_nr has to be a plain signed int. I'm not used to git sources enough yet to be able to make the right decision.

·O·  Pierre Habouzit
··O                                                [email protected]
OOO                                                http://www.madism.org

Could you use (1u << i) instead of (unsigned)(1 << i) ? That looks prettier to me at least.

Nicolas