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# Copyright (C) 2006, 2007, 2009-2011 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""TXT-like base class."""
import dns.exception
import dns.rdata
import dns.tokenizer
class TXTBase(dns.rdata.Rdata):
"""Base class for rdata that is like a TXT record
@ivar strings: the text strings
@type strings: list of string
@see: RFC 1035"""
__slots__ = ['strings']
def __init__(self, rdclass, rdtype, strings):
super(TXTBase, self).__init__(rdclass, rdtype)
if isinstance(strings, str):
strings = [ strings ]
self.strings = strings[:]
def to_text(self, origin=None, relativize=True, **kw):
txt = ''
prefix = ''
for s in self.strings:
txt += '%s"%s"' % (prefix, dns.rdata._escapify(s))
prefix = ' '
return txt
def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
strings = []
while 1:
token = tok.get().unescape()
if token.is_eol_or_eof():
break
if not (token.is_quoted_string() or token.is_identifier()):
raise dns.exception.SyntaxError("expected a string")
if len(token.value) > 255:
raise dns.exception.SyntaxError("string too long")
strings.append(token.value)
if len(strings) == 0:
raise dns.exception.UnexpectedEnd
return cls(rdclass, rdtype, strings)
from_text = classmethod(from_text)
def to_wire(self, file, compress = None, origin = None):
for s in self.strings:
l = len(s)
assert l < 256
byte = chr(l)
file.write(byte)
file.write(s)
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
strings = []
while rdlen > 0:
l = ord(wire[current])
current += 1
rdlen -= 1
if l > rdlen:
raise dns.exception.FormError
s = wire[current : current + l].unwrap()
current += l
rdlen -= l
strings.append(s)
return cls(rdclass, rdtype, strings)
from_wire = classmethod(from_wire)
def _cmp(self, other):
return cmp(self.strings, other.strings)
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