Add float and double fields

mmstats.py

@@ -266,6 +266,16 @@ class ByteField(ReadWriteField):
     buffer_type = ctypes.c_byte
 
 
+class FloatField(BufferedDescriptorField):
+    """32bit Float Field"""
+    buffer_type = ctypes.c_float
+
+
+class DoubleField(BufferedDescriptorField):
+    """64bit Double Precision Float Field"""
+    buffer_type = ctypes.c_double
+
+
 class BoolField(ReadWriteField):
     """Boolean Field"""
     # Avoid potential ambiguity and marshal bools to 0/1 manually

tests/test_types.py

@@ -130,3 +130,22 @@ class SimpleCounter(mmstats.MmStats):
         s.counter.inc(-2)
         self.assertNotEqual(s.counter.value, -1)
 
+    def test_floats(self):
+        class FloatTest(mmstats.MmStats):
+            f = mmstats.FloatField()
+            d = mmstats.DoubleField()
+
+        ft = FloatTest(filename='mmstats-test_floats')
+        self.assertEqual(ft.f, 0.0)
+        self.assertEqual(ft.d, 0.0)
+        ft.d = ft.f = 1.0
+        self.assertEqual(ft.f, 1.0)
+        self.assertEqual(ft.d, 1.0)
+        ft.d = ft.f = -1.0
+        self.assertEqual(ft.f, -1.0)
+        self.assertEqual(ft.d, -1.0)
+        ft.d = ft.f = 1.0 / 3
+        self.assertTrue(ft.f > 0.3)
+        self.assertTrue(ft.d > 0.3)
+        self.assertTrue(ft.f < 0.4)
+        self.assertTrue(ft.d < 0.4)