/
immutable.go
275 lines (231 loc) · 6.57 KB
/
immutable.go
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/*
Copyright 2014 Workiva, LLC
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 rangetree
import "github.com/Workiva/go-datastructures/slice"
type immutableRangeTree struct {
number uint64
top orderedNodes
dimensions uint64
}
func newCache(dimensions uint64) []slice.Int64Slice {
cache := make([]slice.Int64Slice, 0, dimensions-1)
for i := uint64(0); i < dimensions; i++ {
cache = append(cache, slice.Int64Slice{})
}
return cache
}
func (irt *immutableRangeTree) needNextDimension() bool {
return irt.dimensions > 1
}
func (irt *immutableRangeTree) add(nodes *orderedNodes, cache []slice.Int64Slice, entry Entry, added *uint64) {
var node *node
list := nodes
for i := uint64(1); i <= irt.dimensions; i++ {
if isLastDimension(irt.dimensions, i) {
if i != 1 && !cache[i-1].Exists(node.value) {
nodes := make(orderedNodes, len(*list))
copy(nodes, *list)
list = &nodes
cache[i-1].Insert(node.value)
}
newNode := newNode(entry.ValueAtDimension(i), entry, false)
overwritten := list.add(newNode)
if overwritten == nil {
*added++
}
if node != nil {
node.orderedNodes = *list
}
break
}
if i != 1 && !cache[i-1].Exists(node.value) {
nodes := make(orderedNodes, len(*list))
copy(nodes, *list)
list = &nodes
cache[i-1].Insert(node.value)
node.orderedNodes = *list
}
node, _ = list.getOrAdd(entry, i, irt.dimensions)
list = &node.orderedNodes
}
}
// Add will add the provided entries into the tree and return
// a new tree with those entries added.
func (irt *immutableRangeTree) Add(entries ...Entry) *immutableRangeTree {
if len(entries) == 0 {
return irt
}
cache := newCache(irt.dimensions)
top := make(orderedNodes, len(irt.top))
copy(top, irt.top)
added := uint64(0)
for _, entry := range entries {
irt.add(&top, cache, entry, &added)
}
tree := newImmutableRangeTree(irt.dimensions)
tree.top = top
tree.number = irt.number + added
return tree
}
// InsertAtDimension will increment items at and above the given index
// by the number provided. Provide a negative number to to decrement.
// Returned are two lists and the modified tree. The first list is a
// list of entries that were moved. The second is a list entries that
// were deleted. These lists are exclusive.
func (irt *immutableRangeTree) InsertAtDimension(dimension uint64,
index, number int64) (*immutableRangeTree, Entries, Entries) {
if dimension > irt.dimensions || number == 0 {
return irt, nil, nil
}
modified, deleted := make(Entries, 0, 100), make(Entries, 0, 100)
tree := newImmutableRangeTree(irt.dimensions)
tree.top = irt.top.immutableInsert(
dimension, 1, irt.dimensions,
index, number,
&modified, &deleted,
)
tree.number = irt.number - uint64(len(deleted))
return tree, modified, deleted
}
type immutableNodeBundle struct {
list *orderedNodes
index int
previousNode *node
newNode *node
}
func (irt *immutableRangeTree) Delete(entries ...Entry) *immutableRangeTree {
cache := newCache(irt.dimensions)
top := make(orderedNodes, len(irt.top))
copy(top, irt.top)
deleted := uint64(0)
for _, entry := range entries {
irt.delete(&top, cache, entry, &deleted)
}
tree := newImmutableRangeTree(irt.dimensions)
tree.top = top
tree.number = irt.number - deleted
return tree
}
func (irt *immutableRangeTree) delete(top *orderedNodes,
cache []slice.Int64Slice, entry Entry, deleted *uint64) {
path := make([]*immutableNodeBundle, 0, 5)
var index int
var n *node
var local *node
list := top
for i := uint64(1); i <= irt.dimensions; i++ {
value := entry.ValueAtDimension(i)
local, index = list.get(value)
if local == nil { // there's nothing to delete
return
}
nb := &immutableNodeBundle{
list: list,
index: index,
previousNode: n,
}
path = append(path, nb)
n = local
list = &n.orderedNodes
}
*deleted++
for i := len(path) - 1; i >= 0; i-- {
nb := path[i]
if nb.previousNode != nil {
nodes := make(orderedNodes, len(*nb.list))
copy(nodes, *nb.list)
nb.list = &nodes
if len(*nb.list) == 1 {
continue
}
nn := newNode(
nb.previousNode.value,
nb.previousNode.entry,
!isLastDimension(irt.dimensions, uint64(i)+1),
)
nn.orderedNodes = nodes
path[i-1].newNode = nn
}
}
for _, nb := range path {
if nb.newNode == nil {
nb.list.deleteAt(nb.index)
} else {
(*nb.list)[nb.index] = nb.newNode
}
}
}
func (irt *immutableRangeTree) apply(list orderedNodes, interval Interval,
dimension uint64, fn func(*node) bool) bool {
low, high := interval.LowAtDimension(dimension), interval.HighAtDimension(dimension)
if isLastDimension(irt.dimensions, dimension) {
if !list.apply(low, high, fn) {
return false
}
} else {
if !list.apply(low, high, func(n *node) bool {
if !irt.apply(n.orderedNodes, interval, dimension+1, fn) {
return false
}
return true
}) {
return false
}
return true
}
return true
}
// Query will return an ordered list of results in the given
// interval.
func (irt *immutableRangeTree) Query(interval Interval) Entries {
entries := NewEntries()
irt.apply(irt.top, interval, 1, func(n *node) bool {
entries = append(entries, n.entry)
return true
})
return entries
}
func (irt *immutableRangeTree) get(entry Entry) Entry {
on := irt.top
for i := uint64(1); i <= irt.dimensions; i++ {
n, _ := on.get(entry.ValueAtDimension(i))
if n == nil {
return nil
}
if i == irt.dimensions {
return n.entry
}
on = n.orderedNodes
}
return nil
}
// Get returns any entries that exist at the addresses provided by the
// given entries. Entries are returned in the order in which they are
// received. If an entry cannot be found, a nil is returned in its
// place.
func (irt *immutableRangeTree) Get(entries ...Entry) Entries {
result := make(Entries, 0, len(entries))
for _, entry := range entries {
result = append(result, irt.get(entry))
}
return result
}
// Len returns the number of items in this tree.
func (irt *immutableRangeTree) Len() uint64 {
return irt.number
}
func newImmutableRangeTree(dimensions uint64) *immutableRangeTree {
return &immutableRangeTree{
dimensions: dimensions,
}
}