From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Beller <stefanbeller@googlemail.com>
Subject: [PATCH] create_delta_index: simplify condition always evaluating to true
Date: Thu, 15 Aug 2013 23:34:22 +0200
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Cc: Stefan Beller <stefanbeller@googlemail.com>
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When checking the previous lines in that function, we can deduce that
hsize must always be smaller than (1u<<31), since 506049c7df2c6
(fix >4GiB source delta assertion failure), because entries is
capped at an upper bound of 0xfffffffeU, so hsize contains a maximum
value of 0x3fffffff, which is smaller than (1u<<31), so the value of
'i' will never be larger than 31.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
---

Eric, thanks for reviewing my patch.

I applied the first 2 proposals (deduce, entries), but I disagree on
the third, so I reformulated the sentence, as I really meant the variable
i and not it as a pronoun.

Do I understand right, you're suggesting to remove the 
source code comment? I did this now, but I have a bad feeling with it.

The change of this patch surely removes dead code as of now and makes it
more readable. But also it could become alive again, once somebody
changes things nearby and forgets about the assumption, hsize not
exceeding a certain size. That's why I put a comment in there, so 
the future changes nearby may be more careful.

Thanks,
Stefan


 diff-delta.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/diff-delta.c b/diff-delta.c
index 93385e1..3797ce6 100644
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -155,7 +155,7 @@ struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
 		entries = 0xfffffffeU / RABIN_WINDOW;
 	}
 	hsize = entries / 4;
-	for (i = 4; (1u << i) < hsize && i < 31; i++);
+	for (i = 4; (1u << i) < hsize; i++);
 	hsize = 1 << i;
 	hmask = hsize - 1;
 
-- 
1.8.4.rc3.1.gc1ebd90