1 files changed, 133 insertions, 1 deletions
diff --git a/ext/tdb/murmur3.c b/ext/tdb/murmur3.c
index cdc7f73..9980b3d 100644
--- a/ext/tdb/murmur3.c
+++ b/ext/tdb/murmur3.c
@@ -5,7 +5,7 @@
   * MurmurHash3 was written by Austin Appleby, and is placed in the public
   * domain. The author hereby disclaims copyright to this source code.
   *
- * Eric Wong trivially ported this to C for Ruby tdb (32-bit version only)
+ * Eric Wong trivially ported this to C for Ruby tdb (32-bit versions only)
   */
  
  #include <stdint.h>
@@ -97,3 +97,135 @@ unsigned int rbtdb_murmur3a(TDB_DATA * key)
  
          return fmix(h1);
  }
+
+static inline uint64_t rotl64(uint64_t x, int8_t r)
+{
+        return (x << r) | (x >> (64 - r));
+}
+
+#define ROTL64(x,y)        rotl64(x,y)
+
+FORCE_INLINE uint64_t getblock64(const uint64_t * p, int i)
+{
+        return p[i];
+}
+
+FORCE_INLINE uint64_t fmix64(uint64_t k)
+{
+        k ^= k >> 33;
+        k *= BIG_CONSTANT(0xff51afd7ed558ccd);
+        k ^= k >> 33;
+        k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
+        k ^= k >> 33;
+
+        return k;
+}
+
+/* this was a 128-bit hash for x86_64, but we only want 32-bits */
+unsigned int rbtdb_murmur3f(TDB_DATA * key)
+{
+        const uint8_t *data = key->dptr;
+        int len = (int)key->dsize;
+        const int nblocks = len / 16;
+        static const uint32_t seed;
+        uint64_t h1 = seed;
+        uint64_t h2 = seed;
+        uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
+        uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);
+        int i;
+
+        /* body */
+        const uint64_t *blocks = (const uint64_t *)(data);
+
+        for (i = 0; i < nblocks; i++) {
+                uint64_t k1 = getblock64(blocks, i * 2 + 0);
+                uint64_t k2 = getblock64(blocks, i * 2 + 1);
+
+                k1 *= c1;
+                k1 = ROTL64(k1, 31);
+                k1 *= c2;
+                h1 ^= k1;
+
+                h1 = ROTL64(h1, 27);
+                h1 += h2;
+                h1 = h1 * 5 + 0x52dce729;
+
+                k2 *= c2;
+                k2 = ROTL64(k2, 33);
+                k2 *= c1;
+                h2 ^= k2;
+
+                h2 = ROTL64(h2, 31);
+                h2 += h1;
+                h2 = h2 * 5 + 0x38495ab5;
+        }
+
+        /* tail */
+        {
+                const uint8_t *tail = (const uint8_t *)(data + nblocks * 16);
+
+                uint64_t k1 = 0;
+                uint64_t k2 = 0;
+                #define CAST64(x) ((uint64_t)(x))
+
+                switch (len & 15) {
+                case 15:
+                        k2 ^= CAST64(tail[14]) << 48;
+                case 14:
+                        k2 ^= CAST64(tail[13]) << 40;
+                case 13:
+                        k2 ^= CAST64(tail[12]) << 32;
+                case 12:
+                        k2 ^= CAST64(tail[11]) << 24;
+                case 11:
+                        k2 ^= CAST64(tail[10]) << 16;
+                case 10:
+                        k2 ^= CAST64(tail[9]) << 8;
+                case 9:
+                        k2 ^= CAST64(tail[8]) << 0;
+                        k2 *= c2;
+                        k2 = ROTL64(k2, 33);
+                        k2 *= c1;
+                        h2 ^= k2;
+
+                case 8:
+                        k1 ^= CAST64(tail[7]) << 56;
+                case 7:
+                        k1 ^= CAST64(tail[6]) << 48;
+                case 6:
+                        k1 ^= CAST64(tail[5]) << 40;
+                case 5:
+                        k1 ^= CAST64(tail[4]) << 32;
+                case 4:
+                        k1 ^= CAST64(tail[3]) << 24;
+                case 3:
+                        k1 ^= CAST64(tail[2]) << 16;
+                case 2:
+                        k1 ^= CAST64(tail[1]) << 8;
+                case 1:
+                        k1 ^= CAST64(tail[0]) << 0;
+                        k1 *= c1;
+                        k1 = ROTL64(k1, 31);
+                        k1 *= c2;
+                        h1 ^= k1;
+                };
+        }
+
+        /* finalization */
+
+        h1 ^= len;
+        h2 ^= len;
+
+        h1 += h2;
+        h2 += h1;
+
+        h1 = fmix64(h1);
+        h2 = fmix64(h2);
+
+        h1 += h2;
+
+        /* not needed for 32-bit hash */
+        /* h2 += h1; */
+
+        return (unsigned int)h1; /* truncate to 32-bits */
+}