# 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)