Changeset: 58e4d82a6bfd for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=58e4d82a6bfd
Modified Files:
gdk/gdk_hash.h
Branch: leftmart
Log Message:
Optimized version without multiplication.
diffs (46 lines):
diff --git a/gdk/gdk_hash.h b/gdk/gdk_hash.h
--- a/gdk/gdk_hash.h
+++ b/gdk/gdk_hash.h
@@ -139,6 +139,8 @@ gdk_export BUN HASHlist(Hash *h, BUN i);
#define FNV_INIT 0x811c9dc5
#endif
+#define NO_FNV_OPT
+
static inline BUN fnvhash_int(const void *v) {
unsigned int v_int = *(unsigned int *) v;
BUN r = FNV_INIT;
@@ -150,7 +152,16 @@ static inline BUN fnvhash_int(const void
while (octets--) {
r ^= (v_int & 0xff);
v_int >>= 8;
+#ifdef NO_FNV_OPT
r *= FNV_PRIME;
+#else
+#if SIZEOF_BUN == 8
+ r += (r << 1) + (r << 4) + (r << 5) +
+ (r << 7) + (r << 8) + (r << 40);
+#else
+ r += (r<<1) + (r<<4) + (r<<7) + (r<<8) + (r<<24);
+#endif
+#endif
}
return r;
}
@@ -162,7 +173,16 @@ static inline BUN fnvhash_lng(const void
while (octets--) {
r ^= (v_int & 0xff);
v_int >>= 8;
+#ifdef NO_FNV_OPT
r *= FNV_PRIME;
+#else
+#if SIZEOF_BUN == 8
+ r += (r << 1) + (r << 4) + (r << 5) +
+ (r << 7) + (r << 8) + (r << 40);
+#else
+ r += (r<<1) + (r<<4) + (r<<7) + (r<<8) + (r<<24);
+#endif
+#endif
}
return r;
}
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