优化list——head

listhead.go

@@ -8,6 +8,9 @@ type ListHead struct {
 	data interface{}
 }
 
+var dummyData = &struct {
+}{}
+
 func (this *ListHead) Init(data interface{}) {
 	this.next = this
 	this.prev = this
@@ -44,7 +47,12 @@ func (this *ListHead) AddHead(pnew *ListHead) {
 }
 
 func (this *ListHead) FirstEntry() interface{} {
-	return this.next.data
+	for pos := this.next; pos != this; pos = pos.next {
+		if pos.data != dummyData {
+			return pos.data
+		}
+	}
+	return nil
 }
 
 func (this *ListHead) Replace(pnew *ListHead) {
@@ -61,7 +69,18 @@ func (this *ListHead) ReplaceInit(pnew *ListHead) {
 }
 
 func (this *ListHead) Empty() bool {
-	return this.next == this
+	if this.next == this {
+		return true
+	}
+	if this.next.data != dummyData {
+		return false
+	}
+	for pos := this.next; pos != this; pos = pos.next {
+		if pos.data != dummyData {
+			return false
+		}
+	}
+	return true
 }
 
 func (this *ListHead) DelInit() {
@@ -70,13 +89,9 @@ func (this *ListHead) DelInit() {
 	this.prev = this
 }
 
-func (this *ListHead) Next() *ListHead {
-	return this.next
-}
-
 func (this *ListHead) Size() int32 {
 	num := int32(0)
-	this.ForEach_r(
+	this.ForEach(
 		func (data interface{}) bool  {
 			num++
 			return true
@@ -84,35 +99,25 @@ func (this *ListHead) Size() int32 {
 	return num
 }
 
-func (this *ListHead) ForEachFrom(from *ListHead,
-	cb ListHead_Foreach_Func) {
-	for pos := from; pos != this; pos = pos.next {
-		if !cb(pos.data) {
-			break
-		}
-	}
-}
-
 func (this *ListHead) ForEach(cb ListHead_Foreach_Func) {
-	for pos := this.next; pos != this; pos = pos.next {
+	cursor := ListHead{}
-		if !cb(pos.data) {
+	cursor.data = dummyData
+	this.AddHead(&cursor)
+	defer cursor.Del()
+	for ; cursor.next != this; {
+		oldN := cursor.next
+		if cursor.next.data != dummyData && !cb(cursor.next.data) {
 			break
 		}
+		if cursor.next == oldN {
+			cursor.next = oldN.next
+			oldN.next.prev = &cursor
+			oldN.prev = cursor.prev
+			cursor.prev.next = oldN
+			oldN.next = &cursor
+			cursor.prev = oldN
 		}
 	}
-
-func (this *ListHead) ForEach_r(cb ListHead_Foreach_Func) {
-	for pos := this.prev; pos != this; pos = pos.prev {
-		if !cb(pos.data) {
-			break
-		}
-	}
-}
-
-func MakeListHead () *ListHead{
-	l := new(ListHead)
-	l.Init(nil)
-	return l
 }
 
 func NewListHead () *ListHead{