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authorMatthew Heon <matthew.heon@gmail.com>2017-11-01 11:24:59 -0400
committerMatthew Heon <matthew.heon@gmail.com>2017-11-01 11:24:59 -0400
commita031b83a09a8628435317a03f199cdc18b78262f (patch)
treebc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/github.com/tchap/go-patricia/patricia/children.go
parent2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff)
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Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/github.com/tchap/go-patricia/patricia/children.go')
-rw-r--r--vendor/github.com/tchap/go-patricia/patricia/children.go325
1 files changed, 325 insertions, 0 deletions
diff --git a/vendor/github.com/tchap/go-patricia/patricia/children.go b/vendor/github.com/tchap/go-patricia/patricia/children.go
new file mode 100644
index 000000000..a5677c335
--- /dev/null
+++ b/vendor/github.com/tchap/go-patricia/patricia/children.go
@@ -0,0 +1,325 @@
+// 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)
+ 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) 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) total() int {
+ tot := 0
+ for _, child := range list.children {
+ if child != nil {
+ tot = tot + child.total()
+ }
+ }
+ return tot
+}