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# Copyright (C) 2003-2007, 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.
"""DNS TTL conversion."""
import dns.exception
class BadTTL(dns.exception.SyntaxError):
pass
def from_text(text):
"""Convert the text form of a TTL to an integer.
The BIND 8 units syntax for TTLs (e.g. '1w6d4h3m10s') is supported.
@param text: the textual TTL
@type text: string
@raises dns.ttl.BadTTL: the TTL is not well-formed
@rtype: int
"""
if text.isdigit():
total = long(text)
else:
if not text[0].isdigit():
raise BadTTL
total = 0L
current = 0L
for c in text:
if c.isdigit():
current *= 10
current += long(c)
else:
c = c.lower()
if c == 'w':
total += current * 604800L
elif c == 'd':
total += current * 86400L
elif c == 'h':
total += current * 3600L
elif c == 'm':
total += current * 60L
elif c == 's':
total += current
else:
raise BadTTL("unknown unit '%s'" % c)
current = 0
if not current == 0:
raise BadTTL("trailing integer")
if total < 0L or total > 2147483647L:
raise BadTTL("TTL should be between 0 and 2^31 - 1 (inclusive)")
return total
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