1 files changed, 25 insertions, 0 deletions
diff --git a/python/pyspark/mllib/_common.py b/python/pyspark/mllib/_common.py
index e74ba0fabc..769d88dfb9 100644
--- a/python/pyspark/mllib/_common.py
+++ b/python/pyspark/mllib/_common.py
@@ -18,6 +18,9 @@
 from numpy import ndarray, copyto, float64, int64, int32, ones, array_equal, array, dot, shape
 from pyspark import SparkContext
 
+from pyspark.serializers import Serializer
+import struct
+
 # Double vector format:
 #
 # [8-byte 1] [8-byte length] [length*8 bytes of data]
@@ -213,6 +216,28 @@ def _serialize_rating(r):
     intpart[0], intpart[1], doublepart[0] = r
     return ba
 
+class RatingDeserializer(Serializer):
+    def loads(self, stream):
+        length = struct.unpack("!i", stream.read(4))[0]
+        ba = stream.read(length)
+        res = ndarray(shape=(3, ), buffer=ba, dtype="float64", offset=4)
+        return int(res[0]), int(res[1]), res[2]
+
+    def load_stream(self, stream):
+        while True:
+            try:
+                yield self.loads(stream)
+            except struct.error:
+                return
+            except EOFError:
+                return
+
+def _serialize_tuple(t):
+    ba = bytearray(8)
+    intpart = ndarray(shape=[2], buffer=ba, dtype=int32)
+    intpart[0], intpart[1] = t
+    return ba
+
 def _test():
     import doctest
     globs = globals().copy()