1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
#
# Copyright 2003,2004 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# GNU Radio is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
# misc utilities
import types
import exceptions
class seq_with_cursor (object):
__slots__ = [ 'items', 'index' ]
def __init__ (self, items, initial_index = None, initial_value = None):
assert len (items) > 0, "seq_with_cursor: len (items) == 0"
self.items = items
self.set_index (initial_index)
if initial_value is not None:
self.set_index_by_value(initial_value)
def set_index (self, initial_index):
if initial_index is None:
self.index = len (self.items) / 2
elif initial_index >= 0 and initial_index < len (self.items):
self.index = initial_index
else:
raise exceptions.ValueError
def set_index_by_value(self, v):
"""
Set index to the smallest value such that items[index] >= v.
If there is no such item, set index to the maximum value.
"""
self.set_index(0) # side effect!
cv = self.current()
more = True
while cv < v and more:
cv, more = self.next() # side effect!
def next (self):
new_index = self.index + 1
if new_index < len (self.items):
self.index = new_index
return self.items[new_index], True
else:
return self.items[self.index], False
def prev (self):
new_index = self.index - 1
if new_index >= 0:
self.index = new_index
return self.items[new_index], True
else:
return self.items[self.index], False
def current (self):
return self.items[self.index]
def get_seq (self):
return self.items[:] # copy of items
|
