-
Notifications
You must be signed in to change notification settings - Fork 14
/
ordered_map.go
77 lines (68 loc) · 1.53 KB
/
ordered_map.go
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
package collections
type linkedList struct {
next, prev *linkedList
key, value interface{}
}
type OrderedMap struct {
head, tail, current *linkedList
len int
items map[interface{}]*linkedList
}
func NewOrderedMap() *OrderedMap {
headNode := &linkedList{}
tailNode := &linkedList{}
headNode.next, tailNode.prev = tailNode, headNode
return &OrderedMap{
head: headNode,
tail: tailNode,
current: headNode,
len: 0,
items: make(map[interface{}]*linkedList),
}
}
func (om *OrderedMap) Set(key, value interface{}) {
if _, ok := om.items[key]; ok {
om.items[key].value = value
return
}
newNode := &linkedList{prev: om.tail, next: nil, key: key, value: value}
om.items[key] = newNode
om.tail.next = newNode
om.tail = newNode
om.len++
}
func (om *OrderedMap) Get(key interface{}) (interface{}, bool) {
if v, ok := om.items[key]; ok {
return v.value, ok
}
return nil, false
}
func (om *OrderedMap) Delete(key interface{}) bool {
item, ok := om.items[key]
if !ok {
return ok
}
if item.next == nil {
om.tail.prev, om.tail.next = om.tail, nil
} else {
item.prev.next, item.next.prev = item.next, item.prev
}
delete(om.items, key)
item = nil
om.len--
return true
}
func (om *OrderedMap) Iter() (interface{}, interface{}, bool) {
c := om.current.next
if c.next != nil {
om.current = om.current.next
return c.next.key, c.next.value, true
}
return nil, nil, false
}
func (om *OrderedMap) BackToHead() {
om.current = om.head
}
func (om *OrderedMap) Len() int {
return om.len
}