OpenCores
URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [container/] [list/] [list.go] - Blame information for rev 747

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 747 jeremybenn
// Copyright 2009 The Go Authors. All rights reserved.
2
// Use of this source code is governed by a BSD-style
3
// license that can be found in the LICENSE file.
4
 
5
// Package list implements a doubly linked list.
6
//
7
// To iterate over a list (where l is a *List):
8
//      for e := l.Front(); e != nil; e = e.Next() {
9
//              // do something with e.Value
10
//      }
11
//
12
package list
13
 
14
// Element is an element in the linked list.
15
type Element struct {
16
        // Next and previous pointers in the doubly-linked list of elements.
17
        // The front of the list has prev = nil, and the back has next = nil.
18
        next, prev *Element
19
 
20
        // The list to which this element belongs.
21
        list *List
22
 
23
        // The contents of this list element.
24
        Value interface{}
25
}
26
 
27
// Next returns the next list element or nil.
28
func (e *Element) Next() *Element { return e.next }
29
 
30
// Prev returns the previous list element or nil.
31
func (e *Element) Prev() *Element { return e.prev }
32
 
33
// List represents a doubly linked list.
34
// The zero value for List is an empty list ready to use.
35
type List struct {
36
        front, back *Element
37
        len         int
38
}
39
 
40
// Init initializes or clears a List.
41
func (l *List) Init() *List {
42
        l.front = nil
43
        l.back = nil
44
        l.len = 0
45
        return l
46
}
47
 
48
// New returns an initialized list.
49
func New() *List { return new(List) }
50
 
51
// Front returns the first element in the list.
52
func (l *List) Front() *Element { return l.front }
53
 
54
// Back returns the last element in the list.
55
func (l *List) Back() *Element { return l.back }
56
 
57
// Remove removes the element from the list
58
// and returns its Value.
59
func (l *List) Remove(e *Element) interface{} {
60
        l.remove(e)
61
        e.list = nil // do what remove does not
62
        return e.Value
63
}
64
 
65
// remove the element from the list, but do not clear the Element's list field.
66
// This is so that other List methods may use remove when relocating Elements
67
// without needing to restore the list field.
68
func (l *List) remove(e *Element) {
69
        if e.list != l {
70
                return
71
        }
72
        if e.prev == nil {
73
                l.front = e.next
74
        } else {
75
                e.prev.next = e.next
76
        }
77
        if e.next == nil {
78
                l.back = e.prev
79
        } else {
80
                e.next.prev = e.prev
81
        }
82
 
83
        e.prev = nil
84
        e.next = nil
85
        l.len--
86
}
87
 
88
func (l *List) insertBefore(e *Element, mark *Element) {
89
        if mark.prev == nil {
90
                // new front of the list
91
                l.front = e
92
        } else {
93
                mark.prev.next = e
94
        }
95
        e.prev = mark.prev
96
        mark.prev = e
97
        e.next = mark
98
        l.len++
99
}
100
 
101
func (l *List) insertAfter(e *Element, mark *Element) {
102
        if mark.next == nil {
103
                // new back of the list
104
                l.back = e
105
        } else {
106
                mark.next.prev = e
107
        }
108
        e.next = mark.next
109
        mark.next = e
110
        e.prev = mark
111
        l.len++
112
}
113
 
114
func (l *List) insertFront(e *Element) {
115
        if l.front == nil {
116
                // empty list
117
                l.front, l.back = e, e
118
                e.prev, e.next = nil, nil
119
                l.len = 1
120
                return
121
        }
122
        l.insertBefore(e, l.front)
123
}
124
 
125
func (l *List) insertBack(e *Element) {
126
        if l.back == nil {
127
                // empty list
128
                l.front, l.back = e, e
129
                e.prev, e.next = nil, nil
130
                l.len = 1
131
                return
132
        }
133
        l.insertAfter(e, l.back)
134
}
135
 
136
// PushFront inserts the value at the front of the list and returns a new Element containing the value.
137
func (l *List) PushFront(value interface{}) *Element {
138
        e := &Element{nil, nil, l, value}
139
        l.insertFront(e)
140
        return e
141
}
142
 
143
// PushBack inserts the value at the back of the list and returns a new Element containing the value.
144
func (l *List) PushBack(value interface{}) *Element {
145
        e := &Element{nil, nil, l, value}
146
        l.insertBack(e)
147
        return e
148
}
149
 
150
// InsertBefore inserts the value immediately before mark and returns a new Element containing the value.
151
func (l *List) InsertBefore(value interface{}, mark *Element) *Element {
152
        if mark.list != l {
153
                return nil
154
        }
155
        e := &Element{nil, nil, l, value}
156
        l.insertBefore(e, mark)
157
        return e
158
}
159
 
160
// InsertAfter inserts the value immediately after mark and returns a new Element containing the value.
161
func (l *List) InsertAfter(value interface{}, mark *Element) *Element {
162
        if mark.list != l {
163
                return nil
164
        }
165
        e := &Element{nil, nil, l, value}
166
        l.insertAfter(e, mark)
167
        return e
168
}
169
 
170
// MoveToFront moves the element to the front of the list.
171
func (l *List) MoveToFront(e *Element) {
172
        if e.list != l || l.front == e {
173
                return
174
        }
175
        l.remove(e)
176
        l.insertFront(e)
177
}
178
 
179
// MoveToBack moves the element to the back of the list.
180
func (l *List) MoveToBack(e *Element) {
181
        if e.list != l || l.back == e {
182
                return
183
        }
184
        l.remove(e)
185
        l.insertBack(e)
186
}
187
 
188
// Len returns the number of elements in the list.
189
func (l *List) Len() int { return l.len }
190
 
191
// PushBackList inserts each element of ol at the back of the list.
192
func (l *List) PushBackList(ol *List) {
193
        last := ol.Back()
194
        for e := ol.Front(); e != nil; e = e.Next() {
195
                l.PushBack(e.Value)
196
                if e == last {
197
                        break
198
                }
199
        }
200
}
201
 
202
// PushFrontList inserts each element of ol at the front of the list. The ordering of the passed list is preserved.
203
func (l *List) PushFrontList(ol *List) {
204
        first := ol.Front()
205
        for e := ol.Back(); e != nil; e = e.Prev() {
206
                l.PushFront(e.Value)
207
                if e == first {
208
                        break
209
                }
210
        }
211
}

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.