Lib/uu.py

   1 #! /usr/bin/env python
   2
   3 # Copyright 1994 by Lance Ellinghouse
   4 # Cathedral City, California Republic, United States of America.
   5 #                        All Rights Reserved
   6 # Permission to use, copy, modify, and distribute this software and its
   7 # documentation for any purpose and without fee is hereby granted,
   8 # provided that the above copyright notice appear in all copies and that
   9 # both that copyright notice and this permission notice appear in
  10 # supporting documentation, and that the name of Lance Ellinghouse
  11 # not be used in advertising or publicity pertaining to distribution
  12 # of the software without specific, written prior permission.
  13 # LANCE ELLINGHOUSE DISCLAIMS ALL WARRANTIES WITH REGARD TO
  14 # THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  15 # FITNESS, IN NO EVENT SHALL LANCE ELLINGHOUSE CENTRUM BE LIABLE
  16 # FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17 # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18 # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  19 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20 #
  21 # Modified by Jack Jansen, CWI, July 1995:
  22 # - Use binascii module to do the actual line-by-line conversion
  23 #   between ascii and binary. This results in a 1000-fold speedup. The C
  24 #   version is still 5 times faster, though.
  25 # - Arguments more compliant with python standard
  26
  27 """Implementation of the UUencode and UUdecode functions.
  28
  29 encode(in_file, out_file [,name, mode])
  30 decode(in_file [, out_file, mode])
  31 """
  32
  33 import binascii
  34 import os
  35 import sys
  36
  37 __all__ = ["Error", "encode", "decode"]
  38
  39 class Error(Exception):
  40     pass
  41
  42 def encode(in_file, out_file, name=None, mode=None):
  43     """Uuencode file"""
  44     #
  45     # If in_file is a pathname open it and change defaults
  46     #
  47     if in_file == '-':
  48         in_file = sys.stdin
  49     elif isinstance(in_file, basestring):
  50         if name is None:
  51             name = os.path.basename(in_file)
  52         if mode is None:
  53             try:
  54                 mode = os.stat(in_file).st_mode
  55             except AttributeError:
  56                 pass
  57         in_file = open(in_file, 'rb')
  58     #
  59     # Open out_file if it is a pathname
  60     #
  61     if out_file == '-':
  62         out_file = sys.stdout
  63     elif isinstance(out_file, basestring):
  64         out_file = open(out_file, 'w')
  65     #
  66     # Set defaults for name and mode
  67     #
  68     if name is None:
  69         name = '-'
  70     if mode is None:
  71         mode = 0666
  72     #
  73     # Write the data
  74     #
  75     out_file.write('begin %o %s\n' % ((mode&0777),name))
  76     data = in_file.read(45)
  77     while len(data) > 0:
  78         out_file.write(binascii.b2a_uu(data))
  79         data = in_file.read(45)
  80     out_file.write(' \nend\n')
  81
  82
  83 def decode(in_file, out_file=None, mode=None, quiet=0):
  84     """Decode uuencoded file"""
  85     #
  86     # Open the input file, if needed.
  87     #
  88     if in_file == '-':
  89         in_file = sys.stdin
  90     elif isinstance(in_file, basestring):
  91         in_file = open(in_file)
  92     #
  93     # Read until a begin is encountered or we've exhausted the file
  94     #
  95     while True:
  96         hdr = in_file.readline()
  97         if not hdr:
  98             raise Error('No valid begin line found in input file')
  99         if not hdr.startswith('begin'):
 100             continue
 101         hdrfields = hdr.split(' ', 2)
 102         if len(hdrfields) == 3 and hdrfields[0] == 'begin':
 103             try:
 104                 int(hdrfields[1], 8)
 105                 break
 106             except ValueError:
 107                 pass
 108     if out_file is None:
 109         out_file = hdrfields[2].rstrip()
 110         if os.path.exists(out_file):
 111             raise Error('Cannot overwrite existing file: %s' % out_file)
 112     if mode is None:
 113         mode = int(hdrfields[1], 8)
 114     #
 115     # Open the output file
 116     #
 117     if out_file == '-':
 118         out_file = sys.stdout
 119     elif isinstance(out_file, basestring):
 120         fp = open(out_file, 'wb')
 121         try:
 122             os.path.chmod(out_file, mode)
 123         except AttributeError:
 124             pass
 125         out_file = fp
 126     #
 127     # Main decoding loop
 128     #
 129     s = in_file.readline()
 130     while s and s.strip() != 'end':
 131         try:
 132             data = binascii.a2b_uu(s)
 133         except binascii.Error, v:
 134             # Workaround for broken uuencoders by /Fredrik Lundh
 135             nbytes = (((ord(s[0])-32) & 63) * 4 + 5) // 3
 136             data = binascii.a2b_uu(s[:nbytes])
 137             if not quiet:
 138                 sys.stderr.write("Warning: %s\n" % v)
 139         out_file.write(data)
 140         s = in_file.readline()
 141     if not s:
 142         raise Error('Truncated input file')
 143
 144 def test():
 145     """uuencode/uudecode main program"""
 146
 147     import optparse
 148     parser = optparse.OptionParser(usage='usage: %prog [-d] [-t] [input [output]]')
 149     parser.add_option('-d', '--decode', dest='decode', help='Decode (instead of encode)?', default=False, action='store_true')
 150     parser.add_option('-t', '--text', dest='text', help='data is text, encoded format unix-compatible text?', default=False, action='store_true')
 151
 152     (options, args) = parser.parse_args()
 153     if len(args) > 2:
 154         parser.error('incorrect number of arguments')
 155         sys.exit(1)
 156
 157     input = sys.stdin
 158     output = sys.stdout
 159     if len(args) > 0:
 160         input = args[0]
 161     if len(args) > 1:
 162         output = args[1]
 163
 164     if options.decode:
 165         if options.text:
 166             if isinstance(output, basestring):
 167                 output = open(output, 'w')
 168             else:
 169                 print sys.argv[0], ': cannot do -t to stdout'
 170                 sys.exit(1)
 171         decode(input, output)
 172     else:
 173         if options.text:
 174             if isinstance(input, basestring):
 175                 input = open(input, 'r')
 176             else:
 177                 print sys.argv[0], ': cannot do -t from stdin'
 178                 sys.exit(1)
 179         encode(input, output)
 180
 181 if __name__ == '__main__':
 182     test()