Source Code for Module dns.grange

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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   
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