diff -r edb12dad7bf6 Lib/base64.py
--- a/Lib/base64.py	Fri Mar 14 14:20:09 2014 +0000
+++ b/Lib/base64.py	Fri Mar 14 17:00:29 2014 +0100
@@ -274,6 +274,11 @@ def b16decode(s, casefold=False):
 # Ascii85 encoding/decoding
 #
 
+_a85chars = None
+_a85chars2 = None
+_A85START = b"<~"
+_A85END = b"~>"
+
 def _85encode(b, chars, chars2, pad=False, foldnuls=False, foldspaces=False):
     # Helper function for a85encode and b85encode
     if not isinstance(b, bytes_types):
@@ -284,8 +289,6 @@ def _85encode(b, chars, chars2, pad=Fals
         b = b + b'\0' * padding
     words = struct.Struct('!%dI' % (len(b) // 4)).unpack(b)
 
-    a85chars2 = _a85chars2
-    a85chars = _a85chars
     chunks = [b'z' if foldnuls and not word else
               b'y' if foldspaces and word == 0x20202020 else
               (chars2[word // 614125] +
@@ -300,11 +303,6 @@ def _85encode(b, chars, chars2, pad=Fals
 
     return b''.join(chunks)
 
-_A85START = b"<~"
-_A85END = b"~>"
-_a85chars = [bytes([i]) for i in range(33, 118)]
-_a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
-
 def a85encode(b, *, foldspaces=False, wrapcol=0, pad=False, adobe=False):
     """Encode a byte string using Ascii85.
 
@@ -324,6 +322,13 @@ def a85encode(b, *, foldspaces=False, wr
     adobe controls whether the encoded byte sequence is framed with <~ and ~>,
     which is used by the Adobe implementation.
     """
+    global _a85chars, _a85chars2
+    # Delay the initialization of tables to not waste memory
+    # if the function is never called
+    if _a85chars is None:
+        _a85chars = [bytes([i]) for i in range(33, 118)]
+        _a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
+
     result = _85encode(b, _a85chars, _a85chars2, pad, True, foldspaces)
 
     if adobe:
@@ -408,10 +413,8 @@ def a85decode(b, *, foldspaces=False, ad
 
 # The following code is originally taken (with permission) from Mercurial
 
-_b85chars = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
-            b"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
-_b85chars = [bytes([i]) for i in _b85chars]
-_b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
+_b85chars = None
+_b85chars2 = None
 _b85dec = None
 
 def b85encode(b, pad=False):
@@ -420,17 +423,32 @@ def b85encode(b, pad=False):
     If pad is true, the input is padded with "\0" so its length is a multiple of
     4 characters before encoding.
     """
+    global _b85chars, _b85chars2
+    # Delay the initialization of tables to not waste memory
+    # if the function is never called
+    if _b85chars is None:
+        _b85chars = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+                    b"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
+        _b85chars = [bytes([i]) for i in _b85chars]
+    if _b85chars2 is None:
+        _b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
     return _85encode(b, _b85chars, _b85chars2, pad)
 
 def b85decode(b):
     """Decode base85-encoded byte array"""
-    b = _bytes_from_decode_data(b)
-    global _b85dec
+    global _b85chars, _b85dec
+    # Delay the initialization of tables to not waste memory
+    # if the function is never called
+    if _b85chars is None:
+        _b85chars = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+                    b"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
+        _b85chars = [bytes([i]) for i in _b85chars]
     if _b85dec is None:
         _b85dec = [None] * 256
         for i, c in enumerate(_b85chars):
             _b85dec[c[0]] = i
 
+    b = _bytes_from_decode_data(b)
     padding = (-len(b)) % 5
     b = b + b'~' * padding
     out = []
diff -r edb12dad7bf6 Lib/urllib/parse.py
--- a/Lib/urllib/parse.py	Fri Mar 14 14:20:09 2014 +0000
+++ b/Lib/urllib/parse.py	Fri Mar 14 17:00:29 2014 +0100
@@ -472,8 +472,7 @@ def urldefrag(url):
     return _coerce_result(DefragResult(defrag, frag))
 
 _hexdig = '0123456789ABCDEFabcdef'
-_hextobyte = {(a + b).encode(): bytes([int(a + b, 16)])
-              for a in _hexdig for b in _hexdig}
+_hextobyte = None
 
 def unquote_to_bytes(string):
     """unquote_to_bytes('abc%20def') -> b'abc def'."""
@@ -490,6 +489,12 @@ def unquote_to_bytes(string):
         return string
     res = [bits[0]]
     append = res.append
+    # Delay the initialization of the table to not waste memory
+    # if the function is never called
+    global _hextobyte
+    if _hextobyte is None:
+        _hextobyte = {(a + b).encode(): bytes([int(a + b, 16)])
+                      for a in _hexdig for b in _hexdig}
     for item in bits[1:]:
         try:
             append(_hextobyte[item[:2]])