standard encoding for python float (C double) using IEEE 754.

coro/asn1/python.pyx

@@ -13,6 +13,7 @@
 #
 
 from coro.asn1.ber cimport *
+import struct
 
 class EncodingError (Exception):
     pass
@@ -48,6 +49,9 @@ cpdef encode (object ob):
     elif type(ob) is set:
         # Note: we can't use TAG_SET because the decoder returns it as a list
         return _TLV (2 | <int>FLAGS_STRUCTURED | <int>FLAGS_CONTEXT, [encode(x) for x in ob])
+    elif type(ob) is float:
+        # IEEE 754 binary64
+        return _TLV (3 | <int>FLAGS_CONTEXT, struct.pack ('>d', ob))
     else:
         raise EncodingError (ob)
 
@@ -72,6 +76,8 @@ cdef _pydecode_tuple (tuple ob):
             return d
         elif tag == 2:
             return set ([_pydecode (k) for k in data])
+        elif tag == 3:
+            return struct.unpack ('>d', data)[0]
         else:
             raise DecodingError (ob)
     else:

test/test_asn1_python.py

@@ -52,6 +52,17 @@ class Test (unittest.TestCase):
         R (set([0, 1, 2]), (set([0, 1, 2]), 11))
         R (set([(0, 1), 2]), (set([(0, 1), 2]), 13))
 
+    def test_float (self):
+        R = self.round_trip
+        R (3.1415926535, (3.1415926535, 10))
+        R (0.0, (0.0, 10))
+        R (-0.0, (-0.0, 10))
+        import random
+        for i in range (1000):
+            x = random.randint (0, 1000000)
+            R (x/1000.0, (x/1000.0, 10))
+            R (-x/1000.0, (-x/1000.0, 10))
+
     def test_none (self):
         R = self.round_trip
         R (None, (None, 2))