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
|
// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// Package trie implements a simple trie tree for minio server/tools borrows
// idea from - https://godoc.org/golang.org/x/text/internal/triegen.
package trie
// Node trie tree node container carries value and children.
type Node struct {
exists bool
value string
child map[rune]*Node // runes as child.
}
// newNode create a new trie node.
func newNode() *Node {
return &Node{
exists: false,
value: "",
child: make(map[rune]*Node),
}
}
// Trie is a trie container.
type Trie struct {
root *Node
size int
}
// Root returns root node.
func (t *Trie) Root() *Node {
return t.root
}
// Insert insert a key.
func (t *Trie) Insert(key string) {
curNode := t.root
for _, v := range key {
if curNode.child[v] == nil {
curNode.child[v] = newNode()
}
curNode = curNode.child[v]
}
if !curNode.exists {
// increment when new rune child is added.
t.size++
curNode.exists = true
}
// value is stored for retrieval in future.
curNode.value = key
}
// PrefixMatch - prefix match.
func (t *Trie) PrefixMatch(key string) []string {
node, _ := t.findNode(key)
if node == nil {
return nil
}
return t.Walk(node)
}
// Walk the tree.
func (t *Trie) Walk(node *Node) (ret []string) {
if node.exists {
ret = append(ret, node.value)
}
for _, v := range node.child {
ret = append(ret, t.Walk(v)...)
}
return ret
}
// find nodes corresponding to key.
func (t *Trie) findNode(key string) (node *Node, index int) {
curNode := t.root
f := false
for k, v := range key {
if f {
index = k
f = false
}
if curNode.child[v] == nil {
return nil, index
}
curNode = curNode.child[v]
if curNode.exists {
f = true
}
}
if curNode.exists {
index = len(key)
}
return curNode, index
}
// NewTrie create a new trie.
func NewTrie() *Trie {
return &Trie{
root: newNode(),
size: 0,
}
}
|
