[Feature] Use metrohash as well

1 files changed, 141 insertions, 0 deletions

diff --git a/contrib/metrohash/metro.h b/contrib/metrohash/metro.h
new file mode 100644
index 000000000..36c44d65c
--- /dev/null
+++ b/contrib/metrohash/metro.h
@@ -0,0 +1,141 @@
+/*-
+The MIT License (MIT)
+
+Copyright (c) 2015 J. Andrew Rogers
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+#ifndef CONTRIB_METROHASH_METRO_H_
+#define CONTRIB_METROHASH_METRO_H_
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#ifdef _MSC_VER
+typedef unsigned __int32 uint32_t;
+typedef unsigned __int64 uint64_t;
+#else
+#include <stdint.h>
+#endif
+
+/* rotate right idiom recognized by compiler*/
+inline static uint64_t rotate_right(uint64_t v, unsigned k)
+{
+    return (v >> k) | (v << (64 - k));
+}
+
+inline static uint64_t read_u64(const void * const ptr)
+{
+    return * (uint64_t *) ptr;
+}
+
+inline static uint64_t read_u32(const void * const ptr)
+{
+    return * (uint32_t *) ptr;
+}
+
+inline static uint64_t read_u16(const void * const ptr)
+{
+    return * (uint16_t *) ptr;
+}
+
+inline static uint64_t read_u8 (const void * const ptr)
+{
+    return * (uint8_t *) ptr;
+}
+
+static inline uint64_t metrohash64_1(const uint8_t * key, uint64_t len, uint64_t seed)
+{
+    static const uint64_t k0 = 0xC83A91E1;
+    static const uint64_t k1 = 0x8648DBDB;
+    static const uint64_t k2 = 0x7BDEC03B;
+    static const uint64_t k3 = 0x2F5870A5;
+
+    const uint8_t * ptr = key;
+    const uint8_t * const end = ptr + len;
+
+    uint64_t hash = ((((uint64_t) seed) + k2) * k0) + len;
+
+    if (len >= 32)
+    {
+        uint64_t v[4];
+        v[0] = hash;
+        v[1] = hash;
+        v[2] = hash;
+        v[3] = hash;
+
+        do
+        {
+            v[0] += read_u64(ptr) * k0; ptr += 8; v[0] = rotate_right(v[0],29) + v[2];
+            v[1] += read_u64(ptr) * k1; ptr += 8; v[1] = rotate_right(v[1],29) + v[3];
+            v[2] += read_u64(ptr) * k2; ptr += 8; v[2] = rotate_right(v[2],29) + v[0];
+            v[3] += read_u64(ptr) * k3; ptr += 8; v[3] = rotate_right(v[3],29) + v[1];
+        }
+        while (ptr <= (end - 32));
+
+        v[2] ^= rotate_right(((v[0] + v[3]) * k0) + v[1], 33) * k1;
+        v[3] ^= rotate_right(((v[1] + v[2]) * k1) + v[0], 33) * k0;
+        v[0] ^= rotate_right(((v[0] + v[2]) * k0) + v[3], 33) * k1;
+        v[1] ^= rotate_right(((v[1] + v[3]) * k1) + v[2], 33) * k0;
+        hash += v[0] ^ v[1];
+    }
+
+    if ((end - ptr) >= 16)
+    {
+        uint64_t v0 = hash + (read_u64(ptr) * k0); ptr += 8; v0 = rotate_right(v0,33) * k1;
+        uint64_t v1 = hash + (read_u64(ptr) * k1); ptr += 8; v1 = rotate_right(v1,33) * k2;
+        v0 ^= rotate_right(v0 * k0, 35) + v1;
+        v1 ^= rotate_right(v1 * k3, 35) + v0;
+        hash += v1;
+    }
+
+    if ((end - ptr) >= 8)
+    {
+        hash += read_u64(ptr) * k3; ptr += 8;
+        hash ^= rotate_right(hash, 33) * k1;
+
+    }
+
+    if ((end - ptr) >= 4)
+    {
+        hash += read_u32(ptr) * k3; ptr += 4;
+        hash ^= rotate_right(hash, 15) * k1;
+    }
+
+    if ((end - ptr) >= 2)
+    {
+        hash += read_u16(ptr) * k3; ptr += 2;
+        hash ^= rotate_right(hash, 13) * k1;
+    }
+
+    if ((end - ptr) >= 1)
+    {
+        hash += read_u8 (ptr) * k3;
+        hash ^= rotate_right(hash, 25) * k1;
+    }
+
+    hash ^= rotate_right(hash, 33);
+    hash *= k0;
+    hash ^= rotate_right(hash, 33);
+
+    return hash;
+}
+
+#endif /* CONTRIB_METROHASH_METRO_H_ */