1 files changed, 57 insertions, 0 deletions
diff --git a/mmhash.c b/mmhash.c
new file mode 100644
index 0000000..7897b9e
--- /dev/null
+++ b/mmhash.c
@@ -0,0 +1,57 @@
+#include "mmhash.h"
+
+/*-----------------------------------------------------------------------------
+// MurmurHash2, 64-bit versions, by Austin Appleby
+//
+// The same caveats as 32-bit MurmurHash2 apply here - beware of alignment
+// and endian-ness issues if used across multiple platforms.
+//
+// 64-bit hash for 64-bit platforms
+*/
+
+uint64_t mmhash(const void *key, int len, uint64_t seed) {
+    const uint64_t m = 0xc6a4a7935bd1e995LL;
+    const int r = 47;
+
+    uint64_t h = seed ^ (len * m);
+
+    const uint64_t *data = (const uint64_t *)key;
+    const uint64_t *end = data + (len / 8);
+
+    while (data != end) {
+        uint64_t k = *data++;
+
+        k *= m;
+        k ^= k >> r;
+        k *= m;
+
+        h ^= k;
+        h *= m;
+    }
+
+    const unsigned char *data2 = (const unsigned char *)data;
+
+    switch (len & 7) {
+        case 7:
+            h ^= ((uint64_t)data2[6]) << 48;
+        case 6:
+            h ^= ((uint64_t)data2[5]) << 40;
+        case 5:
+            h ^= ((uint64_t)data2[4]) << 32;
+        case 4:
+            h ^= ((uint64_t)data2[3]) << 24;
+        case 3:
+            h ^= ((uint64_t)data2[2]) << 16;
+        case 2:
+            h ^= ((uint64_t)data2[1]) << 8;
+        case 1:
+            h ^= ((uint64_t)data2[0]);
+            h *= m;
+    };
+
+    h ^= h >> r;
+    h *= m;
+    h ^= h >> r;
+
+    return h;
+}