Merge pull request #9 from ewdurbin/pypy_go_faster

fallback to pure python implementation for non CPython interpreters

clandestined/clandestined.py

@@ -1,7 +1,7 @@
 
 from collections import defaultdict
 
-from . import _murmur3
+from . import murmur3
 
 
 class RendezvousHash(object):
@@ -11,7 +11,7 @@ def __init__(self, nodes=None, seed=0):
         self.seed = seed
         if nodes is not None:
             self.nodes = nodes
-        self.hash_function = lambda x: _murmur3.murmur3_32(x, seed)
+        self.hash_function = lambda x: murmur3.murmur3_32(x, seed)
 
     def add_node(self, node):
         if node not in self.nodes:

clandestined/murmur3.py

@@ -1,50 +1,69 @@
-## MurmurHash3 was written by Austin Appleby, and is placed in the public
-## domain. The author hereby disclaims copyright to this source code.
-
-def murmur3_x86_32(data, seed = 0):
-    c1 = 0xcc9e2d51
-    c2 = 0x1b873593
-
-    length = len(data)
-    h1 = seed
-    roundedEnd = (length & 0xfffffffc)  # round down to 4 byte block
-    for i in range(0, roundedEnd, 4):
-      # little endian load order
-      k1 = (ord(data[i]) & 0xff) | ((ord(data[i + 1]) & 0xff) << 8) | \
-           ((ord(data[i + 2]) & 0xff) << 16) | (ord(data[i + 3]) << 24)
-      k1 *= c1
-      k1 = (k1 << 15) | ((k1 & 0xffffffff) >> 17) # ROTL32(k1,15)
-      k1 *= c2
-
-      h1 ^= k1
-      h1 = (h1 << 13) | ((h1 & 0xffffffff) >> 19)  # ROTL32(h1,13)
-      h1 = h1 * 5 + 0xe6546b64
-
-    # tail
-    k1 = 0
-
-    val = length & 0x03
-    if val == 3:
-        k1 = (ord(data[roundedEnd + 2]) & 0xff) << 16
-    # fallthrough
-    if val in [2, 3]:
-        k1 |= (ord(data[roundedEnd + 1]) & 0xff) << 8
-    # fallthrough
-    if val in [1, 2, 3]:
-        k1 |= ord(data[roundedEnd]) & 0xff
-        k1 *= c1
-        k1 = (k1 << 15) | ((k1 & 0xffffffff) >> 17)  # ROTL32(k1,15)
-        k1 *= c2
-        h1 ^= k1
-
-    # finalization
-    h1 ^= length
-
-    # fmix(h1)
-    h1 ^= ((h1 & 0xffffffff) >> 16)
-    h1 *= 0x85ebca6b
-    h1 ^= ((h1 & 0xffffffff) >> 13)
-    h1 *= 0xc2b2ae35
-    h1 ^= ((h1 & 0xffffffff) >> 16)
-
-    return h1 & 0xffffffff
+
+try:
+    import __pypy__
+    MURMUR3_IS_PYPY = True
+except ImportError:
+    MURMUR3_IS_PYPY = False
+
+try:
+    from . import _murmur3
+    MURMUR3_FALLBACK = False
+except ImportError:
+    MURMUR3_FALLBACK = True
+
+
+if MURMUR3_IS_PYPY or MURMUR3_FALLBACK:
+    def murmur3_32(data, seed = 0):
+        """MurmurHash3 was written by Austin Appleby, and is placed in the
+           public domain. The author hereby disclaims copyright to this source
+           code."""
+
+        c1 = 0xcc9e2d51
+        c2 = 0x1b873593
+
+        length = len(data)
+        h1 = seed
+        roundedEnd = (length & 0xfffffffc)  # round down to 4 byte block
+        for i in range(0, roundedEnd, 4):
+          # little endian load order
+          k1 = (ord(data[i]) & 0xff) | ((ord(data[i + 1]) & 0xff) << 8) | \
+               ((ord(data[i + 2]) & 0xff) << 16) | (ord(data[i + 3]) << 24)
+          k1 *= c1
+          k1 = (k1 << 15) | ((k1 & 0xffffffff) >> 17) # ROTL32(k1,15)
+          k1 *= c2
+
+          h1 ^= k1
+          h1 = (h1 << 13) | ((h1 & 0xffffffff) >> 19)  # ROTL32(h1,13)
+          h1 = h1 * 5 + 0xe6546b64
+
+        # tail
+        k1 = 0
+
+        val = length & 0x03
+        if val == 3:
+            k1 = (ord(data[roundedEnd + 2]) & 0xff) << 16
+        # fallthrough
+        if val in [2, 3]:
+            k1 |= (ord(data[roundedEnd + 1]) & 0xff) << 8
+        # fallthrough
+        if val in [1, 2, 3]:
+            k1 |= ord(data[roundedEnd]) & 0xff
+            k1 *= c1
+            k1 = (k1 << 15) | ((k1 & 0xffffffff) >> 17)  # ROTL32(k1,15)
+            k1 *= c2
+            h1 ^= k1
+
+        # finalization
+        h1 ^= length
+
+        # fmix(h1)
+        h1 ^= ((h1 & 0xffffffff) >> 16)
+        h1 *= 0x85ebca6b
+        h1 ^= ((h1 & 0xffffffff) >> 13)
+        h1 *= 0xc2b2ae35
+        h1 ^= ((h1 & 0xffffffff) >> 16)
+
+        return h1 & 0xffffffff
+
+else:
+    murmur3_32 = _murmur3.murmur3_32

clandestined/test/test_collision.py

@@ -11,11 +11,11 @@ def mock_murmur3_32(key, seed=0):
 class CollisionTestCase(unittest.TestCase):
 
     def setUp(self):
-        self.original_murmur3_32 = clandestined._murmur3.murmur3_32
-        clandestined._murmur3.murmur3_32 = mock_murmur3_32
+        self.original_murmur3_32 = clandestined.murmur3.murmur3_32
+        clandestined.murmur3.murmur3_32 = mock_murmur3_32
 
     def tearDown(self):
-        clandestined._murmur3.murmur3_32 = self.original_murmur3_32
+        clandestined.murmur3.murmur3_32 = self.original_murmur3_32
 
     def test_monkey_patch(self):
         rendezvous = RendezvousHash()