Source Code for Module dns.grange

 1  # Copyright (C) 2003-2007, 2009-2011 Nominum, Inc. 
 2  # 
 3  # Permission to use, copy, modify, and distribute this software and its 
 4  # documentation for any purpose with or without fee is hereby granted, 
 5  # provided that the above copyright notice and this permission notice 
 6  # appear in all copies. 
 7  # 
 8  # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES 
 9  # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 
10  # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR 
11  # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 
12  # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 
13  # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 
14  # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
15   
16  """DNS GENERATE range conversion.""" 
17   
18  import dns 
19   
20   
21 -def from_text(text): 
22      """Convert the text form of a range in a GENERATE statement to an 
23      integer. 
24   
25      @param text: the textual range 
26      @type text: string 
27      @return: The start, stop and step values. 
28      @rtype: tuple 
29      """ 
30      # TODO, figure out the bounds on start, stop and step. 
31   
32      step = 1 
33      cur = '' 
34      state = 0 
35      # state   0 1 2 3 4 
36      #         x - y / z 
37      for c in text: 
38          if c == '-' and state == 0: 
39              start = int(cur) 
40              cur = '' 
41              state = 2 
42          elif c == '/': 
43              stop = int(cur) 
44              cur = '' 
45              state = 4 
46          elif c.isdigit(): 
47              cur += c 
48          else: 
49              raise dns.exception.SyntaxError("Could not parse %s" % (c)) 
50   
51      if state in (1, 3): 
52          raise dns.exception.SyntaxError 
53   
54      if state == 2: 
55          stop = int(cur) 
56   
57      if state == 4: 
58          step = int(cur) 
59   
60      assert step >= 1 
61      assert start >= 0 
62      assert start <= stop 
63      # TODO, can start == stop? 
64   
65      return (start, stop, step) 
66