lib/dnspython/dns/ipv4.py

   1 # Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
   2 #
   3 # Permission to use, copy, modify, and distribute this software and its
   4 # documentation for any purpose with or without fee is hereby granted,
   5 # provided that the above copyright notice and this permission notice
   6 # appear in all copies.
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   8 # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
   9 # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10 # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
  11 # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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  13 # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  14 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15
  16 """IPv4 helper functions."""
  17
  18 import struct
  19
  20 import dns.exception
  21
  22 def inet_ntoa(address):
  23     if len(address) != 4:
  24         raise dns.exception.SyntaxError
  25     return '%u.%u.%u.%u' % (ord(address[0]), ord(address[1]),
  26                             ord(address[2]), ord(address[3]))
  27
  28 def inet_aton(text):
  29     parts = text.split('.')
  30     if len(parts) != 4:
  31         raise dns.exception.SyntaxError
  32     for part in parts:
  33         if not part.isdigit():
  34             raise dns.exception.SyntaxError
  35         if len(part) > 1 and part[0] == '0':
  36             # No leading zeros
  37             raise dns.exception.SyntaxError
  38     try:
  39         bytes = [int(part) for part in parts]
  40         return struct.pack('BBBB', *bytes)
  41     except:
  42         raise dns.exception.SyntaxError