1# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license 2 3# Copyright (C) 2012-2017 Nominum, Inc. 4# 5# Permission to use, copy, modify, and distribute this software and its 6# documentation for any purpose with or without fee is hereby granted, 7# provided that the above copyright notice and this permission notice 8# appear in all copies. 9# 10# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES 11# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR 13# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 16# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 18"""DNS GENERATE range conversion.""" 19 20import dns 21 22def from_text(text): 23 """Convert the text form of a range in a ``$GENERATE`` statement to an 24 integer. 25 26 *text*, a ``str``, the textual range in ``$GENERATE`` form. 27 28 Returns a tuple of three ``int`` values ``(start, stop, step)``. 29 """ 30 31 # TODO, figure out the bounds on start, stop and step. 32 step = 1 33 cur = '' 34 state = 0 35 # state 0 1 2 3 4 36 # x - y / z 37 38 if text and text[0] == '-': 39 raise dns.exception.SyntaxError("Start cannot be a negative number") 40 41 for c in text: 42 if c == '-' and state == 0: 43 start = int(cur) 44 cur = '' 45 state = 2 46 elif c == '/': 47 stop = int(cur) 48 cur = '' 49 state = 4 50 elif c.isdigit(): 51 cur += c 52 else: 53 raise dns.exception.SyntaxError("Could not parse %s" % (c)) 54 55 if state in (1, 3): 56 raise dns.exception.SyntaxError() 57 58 if state == 2: 59 stop = int(cur) 60 61 if state == 4: 62 step = int(cur) 63 64 assert step >= 1 65 assert start >= 0 66 assert start <= stop 67 # TODO, can start == stop? 68 69 return (start, stop, step) 70