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Merge branch 'rs/xdiff-fast-hash-fix'

Fixes compilation issue on 32-bit in an earlier series.
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commit 0bc8bea2b4d73b20ce418b88300f498396d0a924 2 parents ec04a27 + 8072766
@gitster gitster authored
Showing with 15 additions and 15 deletions.
  1. +15 −15 xdiff/xutils.c
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30 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;
}
}
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