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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 (
"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
combinedMask() uint64
getChildren() []*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 childContainer struct {
char byte
node *Trie
}
type superDenseChildList struct {
children []childContainer
}
func newSuperDenseChildList() childList {
return &superDenseChildList{
make([]childContainer, 0),
}
}
func (list *superDenseChildList) length() int {
return len(list.children)
}
func (list *superDenseChildList) head() *Trie {
if len(list.children) > 0 {
return list.children[0].node
}
return nil
}
func (list *superDenseChildList) add(child *Trie) childList {
char := child.prefix[0]
list.children = append(list.children, childContainer{
char,
child,
})
return list
}
func (list *superDenseChildList) remove(b byte) {
children := list.children
for i := 0; i < len(children); i++ {
if children[i].char == b {
// children[i] = children[len(children)-1]
// children = children[:len(children)-1]
// children = append(children[:i], children[i+1:]...)
newChildren := make([]childContainer, len(children)-1)
// copy the elements over to avoid "memory leaks"
copy(newChildren, children[:i])
copy(newChildren[i:], children[i+1:])
list.children = newChildren
// list.children = make([]childContainer, len(children))
// copy(list.children, children)
// children = nil
return
}
}
}
func (list *superDenseChildList) replace(b byte, child *Trie) {
children := list.children
for i := 0; i < len(list.children); i++ {
if children[i].char == b {
children[i].node = child
return
}
}
}
func (list *superDenseChildList) next(b byte) *Trie {
children := list.children
for i := 0; i < len(list.children); i++ {
if children[i].char == b {
return children[i].node
}
}
return nil
}
func (list superDenseChildList) combinedMask() uint64 {
var mask uint64
for _, child := range list.children {
// fmt.Printf("child = %+v\n", child)
mask |= child.node.mask
}
return mask
}
func (list *superDenseChildList) getChildren() []*Trie {
children := make([]*Trie, 0, len(list.children))
for _, child := range list.children {
children = append(children, child.node)
}
return children
}
func (list *superDenseChildList) walk(prefix *Prefix, visitor VisitorFunc) error {
for _, child := range list.children {
node := child.node
*prefix = append(*prefix, node.prefix...)
if node.item != nil {
if err := visitor(*prefix, node.item); err != nil {
if err == SkipSubtree {
*prefix = (*prefix)[:len(*prefix)-len(node.prefix)]
continue
}
*prefix = (*prefix)[:len(*prefix)-len(node.prefix)]
return err
}
}
err := node.children.walk(prefix, visitor)
*prefix = (*prefix)[:len(*prefix)-len(node.prefix)]
if err != nil {
return err
}
}
return nil
}
func (list *superDenseChildList) print(w io.Writer, indent int) {
for _, child := range list.children {
child.node.print(w, indent)
}
}
func (list *superDenseChildList) clone() childList {
clones := make([]childContainer, len(list.children))
for i := 0; i < len(list.children); i++ {
child := list.children[i]
clones[i] = childContainer{child.char, child.node.Clone()}
}
return &superDenseChildList{
clones,
}
}
func (list *superDenseChildList) total() int {
return len(list.children)
}
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