feat: Waku v2 bridge

Issue #12610

vendor/github.com/anacrolix/dht/v2/k-nearest-nodes/k-nearest-nodes.go.go

@@ -0,0 +1,103 @@
+package k_nearest_nodes
+
+import (
+	"hash/maphash"
+
+	"github.com/anacrolix/multiless"
+	"github.com/benbjohnson/immutable"
+
+	"github.com/anacrolix/dht/v2/int160"
+	"github.com/anacrolix/dht/v2/krpc"
+)
+
+type Key = krpc.NodeInfo
+
+type Elem struct {
+	Key
+	Data interface{}
+}
+
+type Type struct {
+	inner *immutable.SortedMap
+	k     int
+}
+
+func New(target int160.T, k int) Type {
+	seed := maphash.MakeSeed()
+	return Type{
+		k: k,
+		inner: immutable.NewSortedMap(lessComparer{less: func(_l, _r interface{}) bool {
+			l := _l.(Key)
+			r := _r.(Key)
+			return multiless.New().Cmp(
+				l.ID.Int160().Distance(target).Cmp(r.ID.Int160().Distance(target)),
+			).Lazy(func() multiless.Computation {
+				var lh, rh maphash.Hash
+				lh.SetSeed(seed)
+				rh.SetSeed(seed)
+				lh.WriteString(l.Addr.String())
+				rh.WriteString(r.Addr.String())
+				return multiless.New().Int64(int64(lh.Sum64()), int64(rh.Sum64()))
+			}).Less()
+		}}),
+	}
+}
+
+func (me *Type) Range(f func(Elem)) {
+	iter := me.inner.Iterator()
+	for !iter.Done() {
+		key, value := iter.Next()
+		f(Elem{
+			Key:  key.(Key),
+			Data: value,
+		})
+	}
+}
+
+func (me Type) Len() int {
+	return me.inner.Len()
+}
+
+func (me Type) Push(elem Elem) Type {
+	me.inner = me.inner.Set(elem.Key, elem.Data)
+	for me.inner.Len() > me.k {
+		iter := me.inner.Iterator()
+		iter.Last()
+		key, _ := iter.Next()
+		me.inner = me.inner.Delete(key)
+	}
+	return me
+}
+
+func (me Type) Farthest() (elem Elem) {
+	iter := me.inner.Iterator()
+	iter.Last()
+	if iter.Done() {
+		panic(me.k)
+	}
+	key, value := iter.Next()
+	return Elem{
+		Key:  key.(Key),
+		Data: value,
+	}
+}
+
+func (me Type) Full() bool {
+	return me.Len() >= me.k
+}
+
+type lessFunc func(l, r interface{}) bool
+
+type lessComparer struct {
+	less lessFunc
+}
+
+func (me lessComparer) Compare(i, j interface{}) int {
+	if me.less(i, j) {
+		return -1
+	} else if me.less(j, i) {
+		return 1
+	} else {
+		return 0
+	}
+}