X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fhash.h;h=3f140381c36104ce22eb558e08a9ea75ab52d6a4;hb=36775dad3505929f8370166c33e8e0f04ca96c1c;hp=2015a639fc1b321d319fa4cb4e463e97793e1b54;hpb=cce1d8bd8e326c93579a6ff5d037fe3a60a39f86;p=openvswitch

diff --git a/lib/hash.h b/lib/hash.h
index 2015a639..3f140381 100644
--- a/lib/hash.h
+++ b/lib/hash.h
@@ -16,6 +16,7 @@
 #ifndef HASH_H
 #define HASH_H 1
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ -64,10 +65,20 @@ static inline uint32_t hash_int(uint32_t x, uint32_t basis)
     x ^= x >> 17;
     x -= x << 9;
     x ^= x << 4;
+    x += basis;
     x -= x << 3;
     x ^= x << 10;
     x ^= x >> 15;
-    return x + basis;
+    return x;
+}
+
+/* An attempt at a useful 1-bit hash function.  Has not been analyzed for
+ * quality. */
+static inline uint32_t hash_boolean(bool x, uint32_t basis)
+{
+    enum { P0 = 0xc2b73583 };   /* This is hash_int(1, 0). */
+    enum { P1 = 0xe90f1258 };   /* This is hash_int(2, 0). */
+    return (x ? P0 : P1) ^ HASH_ROT(basis, 1);
 }
 
 static inline uint32_t hash_double(double x, uint32_t basis)