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
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
--!A cross-platform build utility based on Lua
--
-- Licensed to the Apache Software Foundation (ASF) under one
-- or more contributor license agreements. See the NOTICE file
-- distributed with this work for additional information
-- regarding copyright ownership. The ASF licenses this file
-- to you under the Apache License, Version 2.0 (the
-- "License"); you may not use this file except in compliance
-- with the License. You may obtain a copy of the License at
--
-- http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
--
-- Copyright (C) 2015 - 2018, TBOOX Open Source Group.
--
-- @author ruki
-- @file dlist.lua
--
-- load modules
local object = require("ui/object")
-- define module
local dlist = dlist or object { _init = {"_length"} } {0}
-- clear list
function dlist:clear()
self._length = 0
self._first = nil
self._last = nil
end
-- push item to tail
function dlist:push(t)
assert(t)
if self._last then
self._last._next = t
t._prev = self._last
self._last = t
else
self._first = t
self._last = t
end
self._length = self._length + 1
end
-- insert item after the given item
function dlist:insert(t, after)
assert(t)
if not after then
return self:push(t)
end
assert(t ~= after)
if after._next then
after._next._prev = t
t._next = after._next
else
self._last = t
end
t._prev = after
after._next = t
self._length = self._length + 1
end
-- pop item from tail
function dlist:pop()
if not self._last then return end
local t = self._last
if t._prev then
t._prev._next = nil
self._last = t._prev
t._prev = nil
else
self._first = nil
self._last = nil
end
self._length = self._length - 1
return t
end
-- shift item: 1 2 3 <- 2 3
function dlist:shift()
if not self._first then return end
local t = self._first
if t._next then
t._next._prev = nil
self._first = t._next
t._next = nil
else
self._first = nil
self._last = nil
end
self._length = self._length - 1
return t
end
-- unshift item: 1 2 -> t 1 2
function dlist:unshift(t)
assert(t)
if self._first then
self._first._prev = t
t._next = self._first
self._first = t
else
self._first = t
self._last = t
end
self._length = self._length + 1
end
-- remove item
function dlist:remove(t)
assert(t)
if t._next then
if t._prev then
t._next._prev = t._prev
t._prev._next = t._next
else
assert(t == self._first)
t._next._prev = nil
self._first = t._next
end
elseif t._prev then
assert(t == self._last)
t._prev._next = nil
self._last = t._prev
else
assert(t == self._first and t == self._last)
self._first = nil
self._last = nil
end
t._next = nil
t._prev = nil
self._length = self._length - 1
return t
end
-- get first item
function dlist:first()
return self._first
end
-- get last item
function dlist:last()
return self._last
end
-- get next item
function dlist:next(last)
if last then
return last._next
else
return self._first
end
end
-- get the previous item
function dlist:prev(last)
if last then
return last._prev
else
return self._last
end
end
-- get list size
function dlist:size()
return self._length
end
-- is empty?
function dlist:empty()
return self:size() == 0
end
-- get items
--
-- .e.g
--
-- for item in dlist:items() do
-- print(item)
-- end
--
function dlist:items()
-- init iterator
local iter = function (list, item)
return list:next(item)
end
-- return iterator and initialized state
return iter, self, nil
end
-- get reverse items
function dlist:ritems()
-- init iterator
local iter = function (list, item)
return list:prev(item)
end
-- return iterator and initialized state
return iter, self, nil
end
-- return module: dlist
return dlist
|
