sha1_name: make wraparound of the index into ring-buffer explicit

Overflow is defined for unsigned integers, but not for signed ones.
Wrap around explicitly for the new ring-buffer in find_unique_abbrev()
as we did in bb84735c for the ones in sha1_to_hex() and get_pathname(),
thus avoiding signed overflows and getting rid of the magic number 3.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sha1_name.c b/sha1_name.c
index 36ce9b9f45041c6e17e763cee259c284312dc42c..45aa26b3227b235fb918df93ae1da0d9accbdca2 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -474,7 +474,8 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
 {
        static int bufno;
        static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
-       char *hex = hexbuffer[3 & ++bufno];
+       char *hex = hexbuffer[bufno];
+       bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
        find_unique_abbrev_r(hex, sha1, len);
        return hex;
 }