add hg and python

sys/lib/python/email/base64mime.py

@@ -0,0 +1,184 @@
+# Copyright (C) 2002-2006 Python Software Foundation
+# Author: Ben Gertzfield
+# Contact: email-sig@python.org
+
+"""Base64 content transfer encoding per RFCs 2045-2047.
+
+This module handles the content transfer encoding method defined in RFC 2045
+to encode arbitrary 8-bit data using the three 8-bit bytes in four 7-bit
+characters encoding known as Base64.
+
+It is used in the MIME standards for email to attach images, audio, and text
+using some 8-bit character sets to messages.
+
+This module provides an interface to encode and decode both headers and bodies
+with Base64 encoding.
+
+RFC 2045 defines a method for including character set information in an
+`encoded-word' in a header.  This method is commonly used for 8-bit real names
+in To:, From:, Cc:, etc. fields, as well as Subject: lines.
+
+This module does not do the line wrapping or end-of-line character conversion
+necessary for proper internationalized headers; it only does dumb encoding and
+decoding.  To deal with the various line wrapping issues, use the email.Header
+module.
+"""
+
+__all__ = [
+    'base64_len',
+    'body_decode',
+    'body_encode',
+    'decode',
+    'decodestring',
+    'encode',
+    'encodestring',
+    'header_encode',
+    ]
+
+import re
+
+from binascii import b2a_base64, a2b_base64
+from email.utils import fix_eols
+
+CRLF = '\r\n'
+NL = '\n'
+EMPTYSTRING = ''
+
+# See also Charset.py
+MISC_LEN = 7
+
+
+
+# Helpers
+def base64_len(s):
+    """Return the length of s when it is encoded with base64."""
+    groups_of_3, leftover = divmod(len(s), 3)
+    # 4 bytes out for each 3 bytes (or nonzero fraction thereof) in.
+    # Thanks, Tim!
+    n = groups_of_3 * 4
+    if leftover:
+        n += 4
+    return n
+
+
+
+def header_encode(header, charset='iso-8859-1', keep_eols=False,
+                  maxlinelen=76, eol=NL):
+    """Encode a single header line with Base64 encoding in a given charset.
+
+    Defined in RFC 2045, this Base64 encoding is identical to normal Base64
+    encoding, except that each line must be intelligently wrapped (respecting
+    the Base64 encoding), and subsequent lines must start with a space.
+
+    charset names the character set to use to encode the header.  It defaults
+    to iso-8859-1.
+
+    End-of-line characters (\\r, \\n, \\r\\n) will be automatically converted
+    to the canonical email line separator \\r\\n unless the keep_eols
+    parameter is True (the default is False).
+
+    Each line of the header will be terminated in the value of eol, which
+    defaults to "\\n".  Set this to "\\r\\n" if you are using the result of
+    this function directly in email.
+
+    The resulting string will be in the form:
+
+    "=?charset?b?WW/5ciBtYXp66XLrIHf8eiBhIGhhbXBzdGHuciBBIFlv+XIgbWF6euly?=\\n
+      =?charset?b?6yB3/HogYSBoYW1wc3Rh7nIgQkMgWW/5ciBtYXp66XLrIHf8eiBhIGhh?="
+
+    with each line wrapped at, at most, maxlinelen characters (defaults to 76
+    characters).
+    """
+    # Return empty headers unchanged
+    if not header:
+        return header
+
+    if not keep_eols:
+        header = fix_eols(header)
+
+    # Base64 encode each line, in encoded chunks no greater than maxlinelen in
+    # length, after the RFC chrome is added in.
+    base64ed = []
+    max_encoded = maxlinelen - len(charset) - MISC_LEN
+    max_unencoded = max_encoded * 3 // 4
+
+    for i in range(0, len(header), max_unencoded):
+        base64ed.append(b2a_base64(header[i:i+max_unencoded]))
+
+    # Now add the RFC chrome to each encoded chunk
+    lines = []
+    for line in base64ed:
+        # Ignore the last character of each line if it is a newline
+        if line.endswith(NL):
+            line = line[:-1]
+        # Add the chrome
+        lines.append('=?%s?b?%s?=' % (charset, line))
+    # Glue the lines together and return it.  BAW: should we be able to
+    # specify the leading whitespace in the joiner?
+    joiner = eol + ' '
+    return joiner.join(lines)
+
+
+
+def encode(s, binary=True, maxlinelen=76, eol=NL):
+    """Encode a string with base64.
+
+    Each line will be wrapped at, at most, maxlinelen characters (defaults to
+    76 characters).
+
+    If binary is False, end-of-line characters will be converted to the
+    canonical email end-of-line sequence \\r\\n.  Otherwise they will be left
+    verbatim (this is the default).
+
+    Each line of encoded text will end with eol, which defaults to "\\n".  Set
+    this to "\r\n" if you will be using the result of this function directly
+    in an email.
+    """
+    if not s:
+        return s
+
+    if not binary:
+        s = fix_eols(s)
+
+    encvec = []
+    max_unencoded = maxlinelen * 3 // 4
+    for i in range(0, len(s), max_unencoded):
+        # BAW: should encode() inherit b2a_base64()'s dubious behavior in
+        # adding a newline to the encoded string?
+        enc = b2a_base64(s[i:i + max_unencoded])
+        if enc.endswith(NL) and eol <> NL:
+            enc = enc[:-1] + eol
+        encvec.append(enc)
+    return EMPTYSTRING.join(encvec)
+
+
+# For convenience and backwards compatibility w/ standard base64 module
+body_encode = encode
+encodestring = encode
+
+
+
+def decode(s, convert_eols=None):
+    """Decode a raw base64 string.
+
+    If convert_eols is set to a string value, all canonical email linefeeds,
+    e.g. "\\r\\n", in the decoded text will be converted to the value of
+    convert_eols.  os.linesep is a good choice for convert_eols if you are
+    decoding a text attachment.
+
+    This function does not parse a full MIME header value encoded with
+    base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high
+    level email.Header class for that functionality.
+    """
+    if not s:
+        return s
+
+    dec = a2b_base64(s)
+    if convert_eols:
+        return dec.replace(CRLF, convert_eols)
+    return dec
+
+
+# For convenience and backwards compatibility w/ standard base64 module
+body_decode = decode
+decodestring = decode