# 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."""
from typing import Tuple
import dns
def from_text(text: str) -> Tuple[int, int, int]:
"""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)``.
"""
start = -1
stop = -1
step = 1
cur = ""
state = 0
# state 0 1 2
# 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 = 1
elif c == "/":
stop = int(cur)
cur = ""
state = 2
elif c.isdigit():
cur += c
else:
raise dns.exception.SyntaxError(f"Could not parse {c}")
if state == 0:
raise dns.exception.SyntaxError("no stop value specified")
elif state == 1:
stop = int(cur)
else:
assert state == 2
step = int(cur)
assert step >= 1
assert start >= 0
if start > stop:
raise dns.exception.SyntaxError("start must be <= stop")
return (start, stop, step)
