hex: make wraparound of the index into ring-buffer explicit
Overflow is defined for unsigned integers, but not for signed ones. We could make the ring-buffer index in sha1_to_hex() and get_pathname() unsigned to be on the safe side to resolve this, but let's make it explicit that we are wrapping around at whatever the number of elements the ring-buffer has. The compiler is smart enough to turn modulus into bitmask for these codepaths that use ring-buffers of a size that is a power of 2. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
René Scharfe committed
Oct 23, 2016 at 19:57 UTC
bb84735c80dbae6408b79b56f574ae672d2232d4
2 files changed
+4
-2
hex.c
+2
-1
@@ -78,7 +78,8 @@ char *sha1_to_hex(const unsigned char *sha1)
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{
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static int bufno;
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static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
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- return sha1_to_hex_r(hexbuffer[3 & ++bufno], sha1);
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+ bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
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+ return sha1_to_hex_r(hexbuffer[bufno], sha1);
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}
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char *oid_to_hex(const struct object_id *oid)
path.c
+2
-1
@@ -24,7 +24,8 @@ static struct strbuf *get_pathname(void)
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STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
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};
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static int index;
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- struct strbuf *sb = &pathname_array[3 & ++index];
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+ struct strbuf *sb = &pathname_array[index];
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+ index = (index + 1) % ARRAY_SIZE(pathname_array);
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strbuf_reset(sb);
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return sb;
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}