"xdrlib" --- uuencode 檔案的編碼與解碼
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**原始碼：**Lib/uu.py

Deprecated since version 3.11, will be removed in version 3.13: "uu"
模組 (module) 即將被棄用（詳見 **PEP 594**）。"base64" 是個現時常用的
替代方案。

======================================================================

This module encodes and decodes files in uuencode format, allowing
arbitrary binary data to be transferred over ASCII-only connections.
Wherever a file argument is expected, the methods accept a file-like
object.  For backwards compatibility, a string containing a pathname
is also accepted, and the corresponding file will be opened for
reading and writing; the pathname "'-'" is understood to mean the
standard input or output.  However, this interface is deprecated; it's
better for the caller to open the file itself, and be sure that, when
required, the mode is "'rb'" or "'wb'" on Windows.

This code was contributed by Lance Ellinghouse, and modified by Jack
Jansen.

The "uu" module defines the following functions:

uu.encode(in_file, out_file, name=None, mode=None, *, backtick=False)

   Uuencode file *in_file* into file *out_file*.  The uuencoded file
   will have the header specifying *name* and *mode* as the defaults
   for the results of decoding the file. The default defaults are
   taken from *in_file*, or "'-'" and "0o666" respectively.  If
   *backtick* is true, zeros are represented by "'`'" instead of
   spaces.

   在 3.7 版的變更: 新增 *backtick* 參數。

uu.decode(in_file, out_file=None, mode=None, quiet=False)

   This call decodes uuencoded file *in_file* placing the result on
   file *out_file*. If *out_file* is a pathname, *mode* is used to set
   the permission bits if the file must be created. Defaults for
   *out_file* and *mode* are taken from the uuencode header.  However,
   if the file specified in the header already exists, a "uu.Error" is
   raised.

   "decode()" may print a warning to standard error if the input was
   produced by an incorrect uuencoder and Python could recover from
   that error.  Setting *quiet* to a true value silences this warning.

exception uu.Error

   Subclass of "Exception", this can be raised by "uu.decode()" under
   various situations, such as described above, but also including a
   badly formatted header, or truncated input file.

也參考:

  "binascii" 模組
     Support module containing ASCII-to-binary and binary-to-ASCII
     conversions.
