go.mod: update to github.com/tchap/go-patricia/v2 v2.3.1
Signed-off-by: Shengjing Zhu <zhsj@debian.org>
This commit is contained in:
Shengjing Zhu
3
vendor/github.com/tchap/go-patricia/v2/AUTHORS
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vendored
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3
vendor/github.com/tchap/go-patricia/v2/AUTHORS
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This is the complete list of go-patricia copyright holders:
|
||||
|
||||
Ondřej Kupka <ondra.cap@gmail.com>
|
||||
20
vendor/github.com/tchap/go-patricia/v2/LICENSE
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vendored
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20
vendor/github.com/tchap/go-patricia/v2/LICENSE
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@@ -0,0 +1,20 @@
|
||||
The MIT License (MIT)
|
||||
|
||||
Copyright (c) 2014 The AUTHORS
|
||||
|
||||
Permission is hereby granted, free of charge, to any person obtaining a copy of
|
||||
this software and associated documentation files (the "Software"), to deal in
|
||||
the Software without restriction, including without limitation the rights to
|
||||
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
|
||||
the Software, and to permit persons to whom the Software is furnished to do so,
|
||||
subject to the following conditions:
|
||||
|
||||
The above copyright notice and this permission notice shall be included in all
|
||||
copies or substantial portions of the Software.
|
||||
|
||||
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
|
||||
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
|
||||
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
|
||||
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
||||
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
||||
363
vendor/github.com/tchap/go-patricia/v2/patricia/children.go
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363
vendor/github.com/tchap/go-patricia/v2/patricia/children.go
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// Copyright (c) 2014 The go-patricia AUTHORS
|
||||
//
|
||||
// Use of this source code is governed by The MIT License
|
||||
// that can be found in the LICENSE file.
|
||||
|
||||
package patricia
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"io"
|
||||
"sort"
|
||||
)
|
||||
|
||||
type childList interface {
|
||||
length() int
|
||||
head() *Trie
|
||||
add(child *Trie) childList
|
||||
remove(b byte)
|
||||
replace(b byte, child *Trie)
|
||||
next(b byte) *Trie
|
||||
walk(prefix *Prefix, visitor VisitorFunc) error
|
||||
print(w io.Writer, indent int)
|
||||
clone() childList
|
||||
total() int
|
||||
}
|
||||
|
||||
type tries []*Trie
|
||||
|
||||
func (t tries) Len() int {
|
||||
return len(t)
|
||||
}
|
||||
|
||||
func (t tries) Less(i, j int) bool {
|
||||
strings := sort.StringSlice{string(t[i].prefix), string(t[j].prefix)}
|
||||
return strings.Less(0, 1)
|
||||
}
|
||||
|
||||
func (t tries) Swap(i, j int) {
|
||||
t[i], t[j] = t[j], t[i]
|
||||
}
|
||||
|
||||
type sparseChildList struct {
|
||||
children tries
|
||||
}
|
||||
|
||||
func newSparseChildList(maxChildrenPerSparseNode int) childList {
|
||||
return &sparseChildList{
|
||||
children: make(tries, 0, maxChildrenPerSparseNode),
|
||||
}
|
||||
}
|
||||
|
||||
func (list *sparseChildList) length() int {
|
||||
return len(list.children)
|
||||
}
|
||||
|
||||
func (list *sparseChildList) head() *Trie {
|
||||
return list.children[0]
|
||||
}
|
||||
|
||||
func (list *sparseChildList) add(child *Trie) childList {
|
||||
// Search for an empty spot and insert the child if possible.
|
||||
if len(list.children) != cap(list.children) {
|
||||
list.children = append(list.children, child)
|
||||
return list
|
||||
}
|
||||
|
||||
// Otherwise we have to transform to the dense list type.
|
||||
return newDenseChildList(list, child)
|
||||
}
|
||||
|
||||
func (list *sparseChildList) remove(b byte) {
|
||||
for i, node := range list.children {
|
||||
if node.prefix[0] == b {
|
||||
list.children[i] = list.children[len(list.children)-1]
|
||||
list.children[len(list.children)-1] = nil
|
||||
list.children = list.children[:len(list.children)-1]
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// This is not supposed to be reached.
|
||||
panic("removing non-existent child")
|
||||
}
|
||||
|
||||
func (list *sparseChildList) replace(b byte, child *Trie) {
|
||||
// Make a consistency check.
|
||||
if p0 := child.prefix[0]; p0 != b {
|
||||
panic(fmt.Errorf("child prefix mismatch: %v != %v", p0, b))
|
||||
}
|
||||
|
||||
// Seek the child and replace it.
|
||||
for i, node := range list.children {
|
||||
if node.prefix[0] == b {
|
||||
list.children[i] = child
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (list *sparseChildList) next(b byte) *Trie {
|
||||
for _, child := range list.children {
|
||||
if child.prefix[0] == b {
|
||||
return child
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (list *sparseChildList) walk(prefix *Prefix, visitor VisitorFunc) error {
|
||||
|
||||
sort.Sort(list.children)
|
||||
|
||||
for _, child := range list.children {
|
||||
*prefix = append(*prefix, child.prefix...)
|
||||
if child.item != nil {
|
||||
err := visitor(*prefix, child.item)
|
||||
if err != nil {
|
||||
if err == SkipSubtree {
|
||||
*prefix = (*prefix)[:len(*prefix)-len(child.prefix)]
|
||||
continue
|
||||
}
|
||||
*prefix = (*prefix)[:len(*prefix)-len(child.prefix)]
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
err := child.children.walk(prefix, visitor)
|
||||
*prefix = (*prefix)[:len(*prefix)-len(child.prefix)]
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (list *sparseChildList) total() int {
|
||||
tot := 0
|
||||
for _, child := range list.children {
|
||||
if child != nil {
|
||||
tot = tot + child.total()
|
||||
}
|
||||
}
|
||||
return tot
|
||||
}
|
||||
|
||||
func (list *sparseChildList) clone() childList {
|
||||
clones := make(tries, len(list.children), cap(list.children))
|
||||
for i, child := range list.children {
|
||||
clones[i] = child.Clone()
|
||||
}
|
||||
|
||||
return &sparseChildList{
|
||||
children: clones,
|
||||
}
|
||||
}
|
||||
|
||||
func (list *sparseChildList) print(w io.Writer, indent int) {
|
||||
for _, child := range list.children {
|
||||
if child != nil {
|
||||
child.print(w, indent)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
type denseChildList struct {
|
||||
min int
|
||||
max int
|
||||
numChildren int
|
||||
headIndex int
|
||||
children []*Trie
|
||||
}
|
||||
|
||||
func newDenseChildList(list *sparseChildList, child *Trie) childList {
|
||||
var (
|
||||
min int = 255
|
||||
max int = 0
|
||||
)
|
||||
for _, child := range list.children {
|
||||
b := int(child.prefix[0])
|
||||
if b < min {
|
||||
min = b
|
||||
}
|
||||
if b > max {
|
||||
max = b
|
||||
}
|
||||
}
|
||||
|
||||
b := int(child.prefix[0])
|
||||
if b < min {
|
||||
min = b
|
||||
}
|
||||
if b > max {
|
||||
max = b
|
||||
}
|
||||
|
||||
children := make([]*Trie, max-min+1)
|
||||
for _, child := range list.children {
|
||||
children[int(child.prefix[0])-min] = child
|
||||
}
|
||||
children[int(child.prefix[0])-min] = child
|
||||
|
||||
return &denseChildList{
|
||||
min: min,
|
||||
max: max,
|
||||
numChildren: list.length() + 1,
|
||||
headIndex: 0,
|
||||
children: children,
|
||||
}
|
||||
}
|
||||
|
||||
func (list *denseChildList) length() int {
|
||||
return list.numChildren
|
||||
}
|
||||
|
||||
func (list *denseChildList) head() *Trie {
|
||||
return list.children[list.headIndex]
|
||||
}
|
||||
|
||||
func (list *denseChildList) add(child *Trie) childList {
|
||||
b := int(child.prefix[0])
|
||||
var i int
|
||||
|
||||
switch {
|
||||
case list.min <= b && b <= list.max:
|
||||
if list.children[b-list.min] != nil {
|
||||
panic("dense child list collision detected")
|
||||
}
|
||||
i = b - list.min
|
||||
list.children[i] = child
|
||||
|
||||
case b < list.min:
|
||||
children := make([]*Trie, list.max-b+1)
|
||||
i = 0
|
||||
children[i] = child
|
||||
copy(children[list.min-b:], list.children)
|
||||
list.children = children
|
||||
list.min = b
|
||||
|
||||
default: // b > list.max
|
||||
children := make([]*Trie, b-list.min+1)
|
||||
i = b - list.min
|
||||
children[i] = child
|
||||
copy(children, list.children)
|
||||
list.children = children
|
||||
list.max = b
|
||||
}
|
||||
|
||||
list.numChildren++
|
||||
if i < list.headIndex {
|
||||
list.headIndex = i
|
||||
}
|
||||
return list
|
||||
}
|
||||
|
||||
func (list *denseChildList) remove(b byte) {
|
||||
i := int(b) - list.min
|
||||
if list.children[i] == nil {
|
||||
// This is not supposed to be reached.
|
||||
panic("removing non-existent child")
|
||||
}
|
||||
list.numChildren--
|
||||
list.children[i] = nil
|
||||
|
||||
// Update head index.
|
||||
if i == list.headIndex {
|
||||
for ; i < len(list.children); i++ {
|
||||
if list.children[i] != nil {
|
||||
list.headIndex = i
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (list *denseChildList) replace(b byte, child *Trie) {
|
||||
// Make a consistency check.
|
||||
if p0 := child.prefix[0]; p0 != b {
|
||||
panic(fmt.Errorf("child prefix mismatch: %v != %v", p0, b))
|
||||
}
|
||||
|
||||
// Replace the child.
|
||||
list.children[int(b)-list.min] = child
|
||||
}
|
||||
|
||||
func (list *denseChildList) next(b byte) *Trie {
|
||||
i := int(b)
|
||||
if i < list.min || list.max < i {
|
||||
return nil
|
||||
}
|
||||
return list.children[i-list.min]
|
||||
}
|
||||
|
||||
func (list *denseChildList) walk(prefix *Prefix, visitor VisitorFunc) error {
|
||||
for _, child := range list.children {
|
||||
if child == nil {
|
||||
continue
|
||||
}
|
||||
*prefix = append(*prefix, child.prefix...)
|
||||
if child.item != nil {
|
||||
if err := visitor(*prefix, child.item); err != nil {
|
||||
if err == SkipSubtree {
|
||||
*prefix = (*prefix)[:len(*prefix)-len(child.prefix)]
|
||||
continue
|
||||
}
|
||||
*prefix = (*prefix)[:len(*prefix)-len(child.prefix)]
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
err := child.children.walk(prefix, visitor)
|
||||
*prefix = (*prefix)[:len(*prefix)-len(child.prefix)]
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (list *denseChildList) print(w io.Writer, indent int) {
|
||||
for _, child := range list.children {
|
||||
if child != nil {
|
||||
child.print(w, indent)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (list *denseChildList) clone() childList {
|
||||
clones := make(tries, cap(list.children))
|
||||
|
||||
if list.numChildren != 0 {
|
||||
clonedCount := 0
|
||||
for i := list.headIndex; i < len(list.children); i++ {
|
||||
child := list.children[i]
|
||||
if child != nil {
|
||||
clones[i] = child.Clone()
|
||||
clonedCount++
|
||||
if clonedCount == list.numChildren {
|
||||
break
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return &denseChildList{
|
||||
min: list.min,
|
||||
max: list.max,
|
||||
numChildren: list.numChildren,
|
||||
headIndex: list.headIndex,
|
||||
children: clones,
|
||||
}
|
||||
}
|
||||
|
||||
func (list *denseChildList) total() int {
|
||||
tot := 0
|
||||
for _, child := range list.children {
|
||||
if child != nil {
|
||||
tot = tot + child.total()
|
||||
}
|
||||
}
|
||||
return tot
|
||||
}
|
||||
606
vendor/github.com/tchap/go-patricia/v2/patricia/patricia.go
generated
vendored
Normal file
606
vendor/github.com/tchap/go-patricia/v2/patricia/patricia.go
generated
vendored
Normal file
@@ -0,0 +1,606 @@
|
||||
// Copyright (c) 2014 The go-patricia AUTHORS
|
||||
//
|
||||
// Use of this source code is governed by The MIT License
|
||||
// that can be found in the LICENSE file.
|
||||
|
||||
package patricia
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"errors"
|
||||
"fmt"
|
||||
"io"
|
||||
"strings"
|
||||
)
|
||||
|
||||
//------------------------------------------------------------------------------
|
||||
// Trie
|
||||
//------------------------------------------------------------------------------
|
||||
|
||||
const (
|
||||
DefaultMaxPrefixPerNode = 10
|
||||
DefaultMaxChildrenPerSparseNode = 8
|
||||
)
|
||||
|
||||
type (
|
||||
Prefix []byte
|
||||
Item interface{}
|
||||
VisitorFunc func(prefix Prefix, item Item) error
|
||||
)
|
||||
|
||||
// Trie is a generic patricia trie that allows fast retrieval of items by prefix.
|
||||
// and other funky stuff.
|
||||
//
|
||||
// Trie is not thread-safe.
|
||||
type Trie struct {
|
||||
prefix Prefix
|
||||
item Item
|
||||
|
||||
maxPrefixPerNode int
|
||||
maxChildrenPerSparseNode int
|
||||
|
||||
children childList
|
||||
}
|
||||
|
||||
// Public API ------------------------------------------------------------------
|
||||
|
||||
type Option func(*Trie)
|
||||
|
||||
// Trie constructor.
|
||||
func NewTrie(options ...Option) *Trie {
|
||||
trie := &Trie{}
|
||||
|
||||
for _, opt := range options {
|
||||
opt(trie)
|
||||
}
|
||||
|
||||
if trie.maxPrefixPerNode <= 0 {
|
||||
trie.maxPrefixPerNode = DefaultMaxPrefixPerNode
|
||||
}
|
||||
if trie.maxChildrenPerSparseNode <= 0 {
|
||||
trie.maxChildrenPerSparseNode = DefaultMaxChildrenPerSparseNode
|
||||
}
|
||||
|
||||
trie.children = newSparseChildList(trie.maxChildrenPerSparseNode)
|
||||
return trie
|
||||
}
|
||||
|
||||
func MaxPrefixPerNode(value int) Option {
|
||||
return func(trie *Trie) {
|
||||
trie.maxPrefixPerNode = value
|
||||
}
|
||||
}
|
||||
|
||||
func MaxChildrenPerSparseNode(value int) Option {
|
||||
return func(trie *Trie) {
|
||||
trie.maxChildrenPerSparseNode = value
|
||||
}
|
||||
}
|
||||
|
||||
// Clone makes a copy of an existing trie.
|
||||
// Items stored in both tries become shared, obviously.
|
||||
func (trie *Trie) Clone() *Trie {
|
||||
return &Trie{
|
||||
prefix: append(Prefix(nil), trie.prefix...),
|
||||
item: trie.item,
|
||||
maxPrefixPerNode: trie.maxPrefixPerNode,
|
||||
maxChildrenPerSparseNode: trie.maxChildrenPerSparseNode,
|
||||
children: trie.children.clone(),
|
||||
}
|
||||
}
|
||||
|
||||
// Item returns the item stored in the root of this trie.
|
||||
func (trie *Trie) Item() Item {
|
||||
return trie.item
|
||||
}
|
||||
|
||||
// Insert inserts a new item into the trie using the given prefix. Insert does
|
||||
// not replace existing items. It returns false if an item was already in place.
|
||||
func (trie *Trie) Insert(key Prefix, item Item) (inserted bool) {
|
||||
return trie.put(key, item, false)
|
||||
}
|
||||
|
||||
// Set works much like Insert, but it always sets the item, possibly replacing
|
||||
// the item previously inserted.
|
||||
func (trie *Trie) Set(key Prefix, item Item) {
|
||||
trie.put(key, item, true)
|
||||
}
|
||||
|
||||
// Get returns the item located at key.
|
||||
//
|
||||
// This method is a bit dangerous, because Get can as well end up in an internal
|
||||
// node that is not really representing any user-defined value. So when nil is
|
||||
// a valid value being used, it is not possible to tell if the value was inserted
|
||||
// into the tree by the user or not. A possible workaround for this is not to use
|
||||
// nil interface as a valid value, even using zero value of any type is enough
|
||||
// to prevent this bad behaviour.
|
||||
func (trie *Trie) Get(key Prefix) (item Item) {
|
||||
_, node, found, leftover := trie.findSubtree(key)
|
||||
if !found || len(leftover) != 0 {
|
||||
return nil
|
||||
}
|
||||
return node.item
|
||||
}
|
||||
|
||||
// Match returns what Get(prefix) != nil would return. The same warning as for
|
||||
// Get applies here as well.
|
||||
func (trie *Trie) Match(prefix Prefix) (matchedExactly bool) {
|
||||
return trie.Get(prefix) != nil
|
||||
}
|
||||
|
||||
// MatchSubtree returns true when there is a subtree representing extensions
|
||||
// to key, that is if there are any keys in the tree which have key as prefix.
|
||||
func (trie *Trie) MatchSubtree(key Prefix) (matched bool) {
|
||||
_, _, matched, _ = trie.findSubtree(key)
|
||||
return
|
||||
}
|
||||
|
||||
// Visit calls visitor on every node containing a non-nil item
|
||||
// in alphabetical order.
|
||||
//
|
||||
// If an error is returned from visitor, the function stops visiting the tree
|
||||
// and returns that error, unless it is a special error - SkipSubtree. In that
|
||||
// case Visit skips the subtree represented by the current node and continues
|
||||
// elsewhere.
|
||||
func (trie *Trie) Visit(visitor VisitorFunc) error {
|
||||
return trie.walk(nil, visitor)
|
||||
}
|
||||
|
||||
func (trie *Trie) size() int {
|
||||
n := 0
|
||||
|
||||
trie.walk(nil, func(prefix Prefix, item Item) error {
|
||||
n++
|
||||
return nil
|
||||
})
|
||||
|
||||
return n
|
||||
}
|
||||
|
||||
func (trie *Trie) total() int {
|
||||
return 1 + trie.children.total()
|
||||
}
|
||||
|
||||
// VisitSubtree works much like Visit, but it only visits nodes matching prefix.
|
||||
func (trie *Trie) VisitSubtree(prefix Prefix, visitor VisitorFunc) error {
|
||||
// Nil prefix not allowed.
|
||||
if prefix == nil {
|
||||
panic(ErrNilPrefix)
|
||||
}
|
||||
|
||||
// Empty trie must be handled explicitly.
|
||||
if trie.prefix == nil {
|
||||
return nil
|
||||
}
|
||||
|
||||
// Locate the relevant subtree.
|
||||
_, root, found, leftover := trie.findSubtree(prefix)
|
||||
if !found {
|
||||
return nil
|
||||
}
|
||||
prefix = append(prefix, leftover...)
|
||||
|
||||
// Visit it.
|
||||
return root.walk(prefix, visitor)
|
||||
}
|
||||
|
||||
// VisitPrefixes visits only nodes that represent prefixes of key.
|
||||
// To say the obvious, returning SkipSubtree from visitor makes no sense here.
|
||||
func (trie *Trie) VisitPrefixes(key Prefix, visitor VisitorFunc) error {
|
||||
// Nil key not allowed.
|
||||
if key == nil {
|
||||
panic(ErrNilPrefix)
|
||||
}
|
||||
|
||||
// Empty trie must be handled explicitly.
|
||||
if trie.prefix == nil {
|
||||
return nil
|
||||
}
|
||||
|
||||
// Walk the path matching key prefixes.
|
||||
node := trie
|
||||
prefix := key
|
||||
offset := 0
|
||||
for {
|
||||
// Compute what part of prefix matches.
|
||||
common := node.longestCommonPrefixLength(key)
|
||||
key = key[common:]
|
||||
offset += common
|
||||
|
||||
// Partial match means that there is no subtree matching prefix.
|
||||
if common < len(node.prefix) {
|
||||
return nil
|
||||
}
|
||||
|
||||
// Call the visitor.
|
||||
if item := node.item; item != nil {
|
||||
if err := visitor(prefix[:offset], item); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
if len(key) == 0 {
|
||||
// This node represents key, we are finished.
|
||||
return nil
|
||||
}
|
||||
|
||||
// There is some key suffix left, move to the children.
|
||||
child := node.children.next(key[0])
|
||||
if child == nil {
|
||||
// There is nowhere to continue, return.
|
||||
return nil
|
||||
}
|
||||
|
||||
node = child
|
||||
}
|
||||
}
|
||||
|
||||
// Delete deletes the item represented by the given prefix.
|
||||
//
|
||||
// True is returned if the matching node was found and deleted.
|
||||
func (trie *Trie) Delete(key Prefix) (deleted bool) {
|
||||
// Nil prefix not allowed.
|
||||
if key == nil {
|
||||
panic(ErrNilPrefix)
|
||||
}
|
||||
|
||||
// Empty trie must be handled explicitly.
|
||||
if trie.prefix == nil {
|
||||
return false
|
||||
}
|
||||
|
||||
// Find the relevant node.
|
||||
path, found, _ := trie.findSubtreePath(key)
|
||||
if !found {
|
||||
return false
|
||||
}
|
||||
|
||||
node := path[len(path)-1]
|
||||
var parent *Trie
|
||||
if len(path) != 1 {
|
||||
parent = path[len(path)-2]
|
||||
}
|
||||
|
||||
// If the item is already set to nil, there is nothing to do.
|
||||
if node.item == nil {
|
||||
return false
|
||||
}
|
||||
|
||||
// Delete the item.
|
||||
node.item = nil
|
||||
|
||||
// Initialise i before goto.
|
||||
// Will be used later in a loop.
|
||||
i := len(path) - 1
|
||||
|
||||
// In case there are some child nodes, we cannot drop the whole subtree.
|
||||
// We can try to compact nodes, though.
|
||||
if node.children.length() != 0 {
|
||||
goto Compact
|
||||
}
|
||||
|
||||
// In case we are at the root, just reset it and we are done.
|
||||
if parent == nil {
|
||||
node.reset()
|
||||
return true
|
||||
}
|
||||
|
||||
// We can drop a subtree.
|
||||
// Find the first ancestor that has its value set or it has 2 or more child nodes.
|
||||
// That will be the node where to drop the subtree at.
|
||||
for ; i >= 0; i-- {
|
||||
if current := path[i]; current.item != nil || current.children.length() >= 2 {
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
// Handle the case when there is no such node.
|
||||
// In other words, we can reset the whole tree.
|
||||
if i == -1 {
|
||||
path[0].reset()
|
||||
return true
|
||||
}
|
||||
|
||||
// We can just remove the subtree here.
|
||||
node = path[i]
|
||||
if i == 0 {
|
||||
parent = nil
|
||||
} else {
|
||||
parent = path[i-1]
|
||||
}
|
||||
// i+1 is always a valid index since i is never pointing to the last node.
|
||||
// The loop above skips at least the last node since we are sure that the item
|
||||
// is set to nil and it has no children, othewise we would be compacting instead.
|
||||
node.children.remove(path[i+1].prefix[0])
|
||||
|
||||
Compact:
|
||||
// The node is set to the first non-empty ancestor,
|
||||
// so try to compact since that might be possible now.
|
||||
if compacted := node.compact(); compacted != node {
|
||||
if parent == nil {
|
||||
*node = *compacted
|
||||
} else {
|
||||
parent.children.replace(node.prefix[0], compacted)
|
||||
*parent = *parent.compact()
|
||||
}
|
||||
}
|
||||
|
||||
return true
|
||||
}
|
||||
|
||||
// DeleteSubtree finds the subtree exactly matching prefix and deletes it.
|
||||
//
|
||||
// True is returned if the subtree was found and deleted.
|
||||
func (trie *Trie) DeleteSubtree(prefix Prefix) (deleted bool) {
|
||||
// Nil prefix not allowed.
|
||||
if prefix == nil {
|
||||
panic(ErrNilPrefix)
|
||||
}
|
||||
|
||||
// Empty trie must be handled explicitly.
|
||||
if trie.prefix == nil {
|
||||
return false
|
||||
}
|
||||
|
||||
// Locate the relevant subtree.
|
||||
parent, root, found, _ := trie.findSubtree(prefix)
|
||||
if !found {
|
||||
return false
|
||||
}
|
||||
|
||||
// If we are in the root of the trie, reset the trie.
|
||||
if parent == nil {
|
||||
root.reset()
|
||||
return true
|
||||
}
|
||||
|
||||
// Otherwise remove the root node from its parent.
|
||||
parent.children.remove(root.prefix[0])
|
||||
return true
|
||||
}
|
||||
|
||||
// Internal helper methods -----------------------------------------------------
|
||||
|
||||
func (trie *Trie) empty() bool {
|
||||
return trie.item == nil && trie.children.length() == 0
|
||||
}
|
||||
|
||||
func (trie *Trie) reset() {
|
||||
trie.prefix = nil
|
||||
trie.children = newSparseChildList(trie.maxPrefixPerNode)
|
||||
}
|
||||
|
||||
func (trie *Trie) put(key Prefix, item Item, replace bool) (inserted bool) {
|
||||
// Nil prefix not allowed.
|
||||
if key == nil {
|
||||
panic(ErrNilPrefix)
|
||||
}
|
||||
|
||||
var (
|
||||
common int
|
||||
node *Trie = trie
|
||||
child *Trie
|
||||
)
|
||||
|
||||
if node.prefix == nil {
|
||||
if len(key) <= trie.maxPrefixPerNode {
|
||||
node.prefix = key
|
||||
goto InsertItem
|
||||
}
|
||||
node.prefix = key[:trie.maxPrefixPerNode]
|
||||
key = key[trie.maxPrefixPerNode:]
|
||||
goto AppendChild
|
||||
}
|
||||
|
||||
for {
|
||||
// Compute the longest common prefix length.
|
||||
common = node.longestCommonPrefixLength(key)
|
||||
key = key[common:]
|
||||
|
||||
// Only a part matches, split.
|
||||
if common < len(node.prefix) {
|
||||
goto SplitPrefix
|
||||
}
|
||||
|
||||
// common == len(node.prefix) since never (common > len(node.prefix))
|
||||
// common == len(former key) <-> 0 == len(key)
|
||||
// -> former key == node.prefix
|
||||
if len(key) == 0 {
|
||||
goto InsertItem
|
||||
}
|
||||
|
||||
// Check children for matching prefix.
|
||||
child = node.children.next(key[0])
|
||||
if child == nil {
|
||||
goto AppendChild
|
||||
}
|
||||
node = child
|
||||
}
|
||||
|
||||
SplitPrefix:
|
||||
// Split the prefix if necessary.
|
||||
child = new(Trie)
|
||||
*child = *node
|
||||
*node = *NewTrie()
|
||||
node.prefix = child.prefix[:common]
|
||||
child.prefix = child.prefix[common:]
|
||||
child = child.compact()
|
||||
node.children = node.children.add(child)
|
||||
|
||||
AppendChild:
|
||||
// Keep appending children until whole prefix is inserted.
|
||||
// This loop starts with empty node.prefix that needs to be filled.
|
||||
for len(key) != 0 {
|
||||
child := NewTrie()
|
||||
if len(key) <= trie.maxPrefixPerNode {
|
||||
child.prefix = key
|
||||
node.children = node.children.add(child)
|
||||
node = child
|
||||
goto InsertItem
|
||||
} else {
|
||||
child.prefix = key[:trie.maxPrefixPerNode]
|
||||
key = key[trie.maxPrefixPerNode:]
|
||||
node.children = node.children.add(child)
|
||||
node = child
|
||||
}
|
||||
}
|
||||
|
||||
InsertItem:
|
||||
// Try to insert the item if possible.
|
||||
if replace || node.item == nil {
|
||||
node.item = item
|
||||
return true
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
func (trie *Trie) compact() *Trie {
|
||||
// Only a node with a single child can be compacted.
|
||||
if trie.children.length() != 1 {
|
||||
return trie
|
||||
}
|
||||
|
||||
child := trie.children.head()
|
||||
|
||||
// If any item is set, we cannot compact since we want to retain
|
||||
// the ability to do searching by key. This makes compaction less usable,
|
||||
// but that simply cannot be avoided.
|
||||
if trie.item != nil || child.item != nil {
|
||||
return trie
|
||||
}
|
||||
|
||||
// Make sure the combined prefixes fit into a single node.
|
||||
if len(trie.prefix)+len(child.prefix) > trie.maxPrefixPerNode {
|
||||
return trie
|
||||
}
|
||||
|
||||
// Concatenate the prefixes, move the items.
|
||||
child.prefix = append(trie.prefix, child.prefix...)
|
||||
if trie.item != nil {
|
||||
child.item = trie.item
|
||||
}
|
||||
|
||||
return child
|
||||
}
|
||||
|
||||
func (trie *Trie) findSubtree(prefix Prefix) (parent *Trie, root *Trie, found bool, leftover Prefix) {
|
||||
// Find the subtree matching prefix.
|
||||
root = trie
|
||||
for {
|
||||
// Compute what part of prefix matches.
|
||||
common := root.longestCommonPrefixLength(prefix)
|
||||
prefix = prefix[common:]
|
||||
|
||||
// We used up the whole prefix, subtree found.
|
||||
if len(prefix) == 0 {
|
||||
found = true
|
||||
leftover = root.prefix[common:]
|
||||
return
|
||||
}
|
||||
|
||||
// Partial match means that there is no subtree matching prefix.
|
||||
if common < len(root.prefix) {
|
||||
leftover = root.prefix[common:]
|
||||
return
|
||||
}
|
||||
|
||||
// There is some prefix left, move to the children.
|
||||
child := root.children.next(prefix[0])
|
||||
if child == nil {
|
||||
// There is nowhere to continue, there is no subtree matching prefix.
|
||||
return
|
||||
}
|
||||
|
||||
parent = root
|
||||
root = child
|
||||
}
|
||||
}
|
||||
|
||||
func (trie *Trie) findSubtreePath(prefix Prefix) (path []*Trie, found bool, leftover Prefix) {
|
||||
// Find the subtree matching prefix.
|
||||
root := trie
|
||||
var subtreePath []*Trie
|
||||
for {
|
||||
// Append the current root to the path.
|
||||
subtreePath = append(subtreePath, root)
|
||||
|
||||
// Compute what part of prefix matches.
|
||||
common := root.longestCommonPrefixLength(prefix)
|
||||
prefix = prefix[common:]
|
||||
|
||||
// We used up the whole prefix, subtree found.
|
||||
if len(prefix) == 0 {
|
||||
path = subtreePath
|
||||
found = true
|
||||
leftover = root.prefix[common:]
|
||||
return
|
||||
}
|
||||
|
||||
// Partial match means that there is no subtree matching prefix.
|
||||
if common < len(root.prefix) {
|
||||
leftover = root.prefix[common:]
|
||||
return
|
||||
}
|
||||
|
||||
// There is some prefix left, move to the children.
|
||||
child := root.children.next(prefix[0])
|
||||
if child == nil {
|
||||
// There is nowhere to continue, there is no subtree matching prefix.
|
||||
return
|
||||
}
|
||||
|
||||
root = child
|
||||
}
|
||||
}
|
||||
|
||||
func (trie *Trie) walk(actualRootPrefix Prefix, visitor VisitorFunc) error {
|
||||
var prefix Prefix
|
||||
// Allocate a bit more space for prefix at the beginning.
|
||||
if actualRootPrefix == nil {
|
||||
prefix = make(Prefix, 32+len(trie.prefix))
|
||||
copy(prefix, trie.prefix)
|
||||
prefix = prefix[:len(trie.prefix)]
|
||||
} else {
|
||||
prefix = make(Prefix, 32+len(actualRootPrefix))
|
||||
copy(prefix, actualRootPrefix)
|
||||
prefix = prefix[:len(actualRootPrefix)]
|
||||
}
|
||||
|
||||
// Visit the root first. Not that this works for empty trie as well since
|
||||
// in that case item == nil && len(children) == 0.
|
||||
if trie.item != nil {
|
||||
if err := visitor(prefix, trie.item); err != nil {
|
||||
if err == SkipSubtree {
|
||||
return nil
|
||||
}
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
// Then continue to the children.
|
||||
return trie.children.walk(&prefix, visitor)
|
||||
}
|
||||
|
||||
func (trie *Trie) longestCommonPrefixLength(prefix Prefix) (i int) {
|
||||
for ; i < len(prefix) && i < len(trie.prefix) && prefix[i] == trie.prefix[i]; i++ {
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
func (trie *Trie) dump() string {
|
||||
writer := &bytes.Buffer{}
|
||||
trie.print(writer, 0)
|
||||
return writer.String()
|
||||
}
|
||||
|
||||
func (trie *Trie) print(writer io.Writer, indent int) {
|
||||
fmt.Fprintf(writer, "%s%s %v\n", strings.Repeat(" ", indent), string(trie.prefix), trie.item)
|
||||
trie.children.print(writer, indent+2)
|
||||
}
|
||||
|
||||
// Errors ----------------------------------------------------------------------
|
||||
|
||||
var (
|
||||
SkipSubtree = errors.New("Skip this subtree")
|
||||
ErrNilPrefix = errors.New("Nil prefix passed into a method call")
|
||||
)
|
||||
Reference in New Issue
Block a user