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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2012-2017 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 GENERATE range conversion."""
import dns
def from_text(text):
"""Convert the text form of a range in a ``$GENERATE`` statement to an
integer.
*text*, a ``str``, the textual range in ``$GENERATE`` form.
Returns a tuple of three ``int`` values ``(start, stop, step)``.
"""
# TODO, figure out the bounds on start, stop and step.
step = 1
cur = ''
state = 0
# state 0 1 2 3 4
# x - y / z
if text and text[0] == '-':
raise dns.exception.SyntaxError("Start cannot be a negative number")
for c in text:
if c == '-' and state == 0:
start = int(cur)
cur = ''
state = 2
elif c == '/':
stop = int(cur)
cur = ''
state = 4
elif c.isdigit():
cur += c
else:
raise dns.exception.SyntaxError("Could not parse %s" % (c))
if state in (1, 3):
raise dns.exception.SyntaxError()
if state == 2:
stop = int(cur)
if state == 4:
step = int(cur)
assert step >= 1
assert start >= 0
assert start <= stop
# TODO, can start == stop?
return (start, stop, step)