The email package version 1.0, prototyped as mimelib

<http://sf.net/projects/mimelib>.  There /are/ API differences between
mimelib and email, but most of the implementations are shared (except
where cool Py2.2 stuff like generators are used).

Lib/email/Encoders.py

@@ -0,0 +1,68 @@
+# Copyright (C) 2001 Python Software Foundation
+# Author: barry@zope.com (Barry Warsaw)
+
+"""Module containing encoding functions for Image.Image and Text.Text.
+"""
+
+import base64
+from quopri import encodestring as _encodestring
+
+
+
+# Helpers
+def _qencode(s):
+    return _encodestring(s, quotetabs=1)
+
+def _bencode(s):
+    # We can't quite use base64.encodestring() since it tacks on a "courtesy
+    # newline".  Blech!
+    if not s:
+        return s
+    hasnewline = (s[-1] == '\n')
+    value = base64.encodestring(s)
+    if not hasnewline and value[-1] == '\n':
+        return value[:-1]
+    return value
+
+
+
+def encode_base64(msg):
+    """Encode the message's payload in Base64.
+
+    Also, add an appropriate Content-Transfer-Encoding: header.
+    """
+    orig = msg.get_payload()
+    encdata = _bencode(orig)
+    msg.set_payload(encdata)
+    msg['Content-Transfer-Encoding'] = 'base64'
+
+
+
+def encode_quopri(msg):
+    """Encode the message's payload in Quoted-Printable.
+
+    Also, add an appropriate Content-Transfer-Encoding: header.
+    """
+    orig = msg.get_payload()
+    encdata = _qencode(orig)
+    msg.set_payload(encdata)
+    msg['Content-Transfer-Encoding'] = 'quoted-printable'
+
+
+
+def encode_7or8bit(msg):
+    """Set the Content-Transfer-Encoding: header to 7bit or 8bit."""
+    orig = msg.get_payload()
+    # We play a trick to make this go fast.  If encoding to ASCII succeeds, we
+    # know the data must be 7bit, otherwise treat it as 8bit.
+    try:
+        orig.encode('ascii')
+    except UnicodeError:
+        msg['Content-Transfer-Encoding'] = '8bit'
+    else:
+        msg['Content-Transfer-Encoding'] = '7bit'
+
+
+
+def encode_noop(msg):
+    """Do nothing."""