mirror of https://github.com/minio/minio.git
119 lines
2.4 KiB
Go
119 lines
2.4 KiB
Go
/*
|
|
* MinIO Cloud Storage, (C) 2014, 2015, 2016, 2017 MinIO, Inc.
|
|
*
|
|
* Licensed 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.
|
|
*/
|
|
|
|
// 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
|
|
}
|
|
|
|
// 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,
|
|
}
|
|
}
|