Jim Fulton writes:

gvanrossum · gvanrossum · commit d370379186e1 · 1998-10-22T20:15:36.000Z
"""
I've attached a long overdue patch to pickle.py to bring it to format
1.3, which is the same as 1.2 except that the binary float format
is supported.  This is done using the new platform-indepent format
features of struct.

This patch also gets rid of the undocumented obsolete Pickler
dump_special method.
"""
diff --git a/Lib/pickle.py b/Lib/pickle.py
@@ -27,10 +27,13 @@
 
 from types import *
 from copy_reg import dispatch_table, safe_constructors
-import string, marshal, sys
+import string
+import marshal
+import sys
+import struct
 
-format_version = "1.2"                  # File format version we write
-compatible_formats = ["1.0", "1.1"]     # Old format versions we can read
+format_version = "1.3"                     # File format version we write
+compatible_formats = ["1.0", "1.1", "1.2"] # Old format versions we can read
 
 mdumps = marshal.dumps
 mloads = marshal.loads
@@ -81,6 +84,7 @@
 TUPLE           = 't'
 EMPTY_TUPLE     = ')'
 SETITEMS        = 'u'
+BINFLOAT        = 'G'
 
 class Pickler:
 
@@ -93,14 +97,6 @@ def dump(self, object):
         self.save(object)
         self.write(STOP)
 
-    def dump_special(self, callable, args, state = None):
-        if type(args) is not TupleType and args is not None:
-            raise PicklingError, "Second argument to dump_special " \
-                                 "must be a tuple"
-
-        self.save_reduce(callable, args, state)
-        self.write(STOP)
-
     def put(self, i):
         if (self.bin):
             s = mdumps(i)[1:]
@@ -252,8 +248,11 @@ def save_long(self, object):
         self.write(LONG + `object` + '\n')
     dispatch[LongType] = save_long
 
-    def save_float(self, object):
-        self.write(FLOAT + `object` + '\n')
+    def save_float(self, object, pack=struct.pack):
+        if self.bin:
+            self.write(BINFLOAT + pack('>d', object))
+        else:
+            self.write(FLOAT + `object` + '\n')
     dispatch[FloatType] = save_float
 
     def save_string(self, object):
@@ -552,6 +551,10 @@ def load_float(self):
         self.append(string.atof(self.readline()[:-1]))
     dispatch[FLOAT] = load_float
 
+    def load_binfloat(self, unpack=struct.unpack):
+        self.append(unpack('>d', self.read(8))[0])
+    dispatch[BINFLOAT] = load_binfloat
+
     def load_string(self):
         self.append(eval(self.readline()[:-1],
                          {'__builtins__': {}})) # Let's be careful
