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authorJunio C Hamano <gitster@pobox.com>2012-05-25 19:05:02 (GMT)
committerJunio C Hamano <gitster@pobox.com>2012-05-25 19:05:02 (GMT)
commit0bc8bea2b4d73b20ce418b88300f498396d0a924 (patch)
tree54daaa09d4b2993fefa334cc4d8e9860a80037d9
parentec04a275b495a7d786b49aeca2eef7f45fb00c48 (diff)
parent8072766cc6756e9218ea7c9433b097b696329407 (diff)
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Merge branch 'rs/xdiff-fast-hash-fix'
Fixes compilation issue on 32-bit in an earlier series.
-rw-r--r--xdiff/xutils.c30
1 files changed, 15 insertions, 15 deletions
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
index ae6ce0d..9504eae 100644
--- a/xdiff/xutils.c
+++ b/xdiff/xutils.c
@@ -251,9 +251,11 @@ static unsigned long xdl_hash_record_with_whitespace(char const **data,
#ifdef XDL_FAST_HASH
-#define ONEBYTES 0x0101010101010101ul
-#define NEWLINEBYTES 0x0a0a0a0a0a0a0a0aul
-#define HIGHBITS 0x8080808080808080ul
+#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
+
+#define ONEBYTES REPEAT_BYTE(0x01)
+#define NEWLINEBYTES REPEAT_BYTE(0x0a)
+#define HIGHBITS REPEAT_BYTE(0x80)
/* Return the high bit set in the first byte that is a zero */
static inline unsigned long has_zero(unsigned long a)
@@ -270,21 +272,19 @@ static inline long count_masked_bytes(unsigned long mask)
* that works for the bytemasks without having to
* mask them first.
*/
- return mask * 0x0001020304050608 >> 56;
- } else {
/*
- * Modified Carl Chatfield G+ version for 32-bit *
+ * return mask * 0x0001020304050608 >> 56;
*
- * (a) gives us
- * -1 (0, ff), 0 (ffff) or 1 (ffffff)
- * (b) gives us
- * 0 for 0, 1 for (ff ffff ffffff)
- * (a+b+1) gives us
- * correct 0-3 bytemask count result
+ * Doing it like this avoids warnings on 32-bit machines.
*/
- long a = (mask - 256) >> 23;
- long b = mask & 1;
- return a + b + 1;
+ long a = (REPEAT_BYTE(0x01) / 0xff + 1);
+ return mask * a >> (sizeof(long) * 7);
+ } else {
+ /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
+ /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
+ long a = (0x0ff0001 + mask) >> 23;
+ /* Fix the 1 for 00 case */
+ return a & mask;
}
}