1 files changed, 230 insertions, 0 deletions
diff --git a/vendor/src/github.com/tchap/go-patricia/patricia/children.go b/vendor/src/github.com/tchap/go-patricia/patricia/children.go
new file mode 100644
index 0000000000..07d3326335
--- /dev/null
+++ b/vendor/src/github.com/tchap/go-patricia/patricia/children.go
@@ -0,0 +1,230 @@
+// 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
+
+// Max prefix length that is kept in a single trie node.
+var MaxPrefixPerNode = 10
+
+// Max children to keep in a node in the sparse mode.
+const MaxChildrenPerSparseNode = 8
+
+type childList interface {
+	length() int
+	head() *Trie
+	add(child *Trie) childList
+	replace(b byte, child *Trie)
+	remove(child *Trie)
+	next(b byte) *Trie
+	walk(prefix *Prefix, visitor VisitorFunc) error
+}
+
+type sparseChildList struct {
+	children []*Trie
+}
+
+func newSparseChildList() childList {
+	return &sparseChildList{
+		children: make([]*Trie, 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) replace(b byte, child *Trie) {
+	// 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) remove(child *Trie) {
+	for i, node := range list.children {
+		if node.prefix[0] == child.prefix[0] {
+			list.children = append(list.children[:i], list.children[i+1:]...)
+			return
+		}
+	}
+
+	// This is not supposed to be reached.
+	panic("removing non-existent child")
+}
+
+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 {
+	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
+}
+
+type denseChildList struct {
+	min      int
+	max      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, max, children}
+}
+
+func (list *denseChildList) length() int {
+	return list.max - list.min + 1
+}
+
+func (list *denseChildList) head() *Trie {
+	return list.children[0]
+}
+
+func (list *denseChildList) add(child *Trie) childList {
+	b := int(child.prefix[0])
+
+	switch {
+	case list.min <= b && b <= list.max:
+		if list.children[b-list.min] != nil {
+			panic("dense child list collision detected")
+		}
+		list.children[b-list.min] = child
+
+	case b < list.min:
+		children := make([]*Trie, list.max-b+1)
+		children[0] = 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)
+		children[b-list.min] = child
+		copy(children, list.children)
+		list.children = children
+		list.max = b
+	}
+
+	return list
+}
+
+func (list *denseChildList) replace(b byte, child *Trie) {
+	list.children[int(b)-list.min] = nil
+	list.children[int(child.prefix[0])-list.min] = child
+}
+
+func (list *denseChildList) remove(child *Trie) {
+	i := int(child.prefix[0]) - list.min
+	if list.children[i] == nil {
+		// This is not supposed to be reached.
+		panic("removing non-existent child")
+	}
+	list.children[i] = nil
+}
+
+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
+}