Add murmurhash3
And use it in bloom, add it to the crc tester as well.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/lib/murmur3.c b/lib/murmur3.c
new file mode 100644
index 0000000..e316f59
--- /dev/null
+++ b/lib/murmur3.c
@@ -0,0 +1,68 @@
+#include "murmur3.h"
+
+static inline uint32_t rotl32(uint32_t x, int8_t r)
+{
+ return (x << r) | (x >> (32 - r));
+}
+
+//-----------------------------------------------------------------------------
+// Finalization mix - force all bits of a hash block to avalanche
+
+static inline uint32_t fmix32(uint32_t h)
+{
+ h ^= h >> 16;
+ h *= 0x85ebca6b;
+ h ^= h >> 13;
+ h *= 0xc2b2ae35;
+ h ^= h >> 16;
+
+ return h;
+}
+
+static uint32_t murmur3_tail(const uint8_t *data, const int nblocks,
+ uint32_t len, const uint32_t c1,
+ const uint32_t c2, uint32_t h1)
+{
+ const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
+
+ uint32_t k1 = 0;
+ switch (len & 3) {
+ case 3:
+ k1 ^= tail[2] << 16;
+ case 2:
+ k1 ^= tail[1] << 8;
+ case 1:
+ k1 ^= tail[0];
+ k1 *= c1;
+ k1 = rotl32(k1, 15);
+ k1 *= c2;
+ h1 ^= k1;
+ };
+
+ return fmix32(h1 ^ len);
+}
+
+uint32_t murmurhash3(const void *key, uint32_t len, uint32_t seed)
+{
+ const uint8_t *data = (const uint8_t *)key;
+ const int nblocks = len / 4;
+ uint32_t h1 = seed;
+ const uint32_t c1 = 0xcc9e2d51;
+ const uint32_t c2 = 0x1b873593;
+ const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
+ int i;
+
+ for (i = -nblocks; i; i++) {
+ uint32_t k1 = blocks[i];
+
+ k1 *= c1;
+ k1 = rotl32(k1, 15);
+ k1 *= c2;
+
+ h1 ^= k1;
+ h1 = rotl32(h1, 13);
+ h1 = h1 * 5 + 0xe6546b64;
+ }
+
+ return murmur3_tail(data, nblocks, len, c1, c2, h1);
+}