add initial skip list Containers impl

roaring/containers.go

@@ -0,0 +1,85 @@
+package roaring
+
+import (
+	"github.com/pilosa/fast-skiplist"
+)
+
+func NewSkipListContainers() *SkipListContainers {
+	return &SkipListContainers{
+		list: skiplist.New(),
+	}
+}
+
+type SkipListContainers struct {
+	list *skiplist.SkipList
+}
+
+func (slc *SkipListContainers) Get(key uint64) *container {
+	return slc.list.Get(key).Value().(*container)
+}
+
+func (slc *SkipListContainers) Put(key uint64, c *container) {
+	slc.list.Set(key, c)
+}
+
+func (slc *SkipListContainers) Remove(key uint64) {
+	slc.list.Remove(key)
+}
+
+func (slc *SkipListContainers) GetOrCreate(key uint64) *container {
+	el := slc.list.Get(key)
+	if el == nil {
+		return slc.list.Set(key, newContainer()).Value().(*container)
+	}
+	return el.Value().(*container)
+}
+
+func (slc *SkipListContainers) Clone() Containers {
+	nslc := NewSkipListContainers()
+	for c := slc.list.Front(); c != nil; c = c.Next() {
+		nslc.list.Set(c.Key(), c.Value().(*container).clone())
+	}
+	return nslc
+}
+
+func (slc *SkipListContainers) Last() (key uint64, c *container) {
+	el := slc.list.Last()
+	return el.Key(), el.Value().(*container)
+}
+
+func (slc *SkipListContainers) Size() int {
+	return slc.list.Length()
+}
+
+func (slc *SkipListContainers) Iterator(key uint64) (citer Contiterator, found bool) {
+	el := slc.list.GetNext(key)
+	if el.Key() == key {
+		found = true
+	}
+
+	return &SLCIterator{
+		el: el,
+	}, found
+
+}
+
+type SLCIterator struct {
+	started bool
+	el      *skiplist.Element
+}
+
+func (i *SLCIterator) Next() bool {
+	if i.el == nil {
+		return false
+	}
+	if !i.started {
+		i.started = true
+		return true
+	}
+	i.el = i.el.Next()
+	return i.el != nil
+}
+
+func (i *SLCIterator) Value() (uint64, *container) {
+	return i.el.Key(), i.el.Value().(*container)
+}