Added Eviction and Options setup

1 files changed, 73 insertions, 50 deletions

diff --git a/evict.go b/evict.go
index 5e75342..dabbe6a 100644
--- a/evict.go
+++ b/evict.go
@@ -5,88 +5,100 @@ import "errors"
 type EvictionPolicyType int
 
 const (
-	StrategyNone EvictionPolicyType = iota
-	StrategyFIFO
-	StrategyLRU
-	StrategyLFU
+	PolicyNone EvictionPolicyType = iota
+	PolicyFIFO
+	PolicyLRU
+	PolicyLFU
+	PolicyLTR
 )
 
-type EvictionStrategies interface {
-	OnInsert(n *Node)
-	OnAccess(n *Node)
-	Evict() *Node
+type evictionStrategies interface {
+	OnInsert(n *node)
+	OnAccess(n *node)
+	Evict() *node
 }
 
-type EvictionPolicy struct {
-	EvictionStrategies
+type evictionPolicy struct {
+	evictionStrategies
 	Type  EvictionPolicyType
-	evict *Node
+	evict *node
 }
 
-func (e *EvictionPolicy) SetPolicy(y EvictionPolicyType) error {
-	store := map[EvictionPolicyType]func() EvictionStrategies{
-		StrategyNone: func() EvictionStrategies {
-			return NoneStrategies{evict: e.evict}
+func (e *evictionPolicy) SetPolicy(y EvictionPolicyType) error {
+	store := map[EvictionPolicyType]func() evictionStrategies{
+		PolicyNone: func() evictionStrategies {
+			return nonePolicy{evict: e.evict}
 		},
-		StrategyFIFO: func() EvictionStrategies {
-			return FIFOStrategies{evict: e.evict}
+		PolicyFIFO: func() evictionStrategies {
+			return fifoPolicy{evict: e.evict}
 		},
-		StrategyLRU: func() EvictionStrategies {
-			return LRUStrategies{evict: e.evict}
+		PolicyLRU: func() evictionStrategies {
+			return lruPolicy{evict: e.evict}
+		},
+		PolicyLFU: func() evictionStrategies {
+			return lfuPolicy{evict: e.evict}
 		},
 	}
 	factory, ok := store[y]
 	if !ok {
-		return errors.New("Invalid Policy")
+		return errors.New("invalid olicy")
 	}
-	e.EvictionStrategies = factory()
+	e.evictionStrategies = factory()
 	return nil
 }
 
-type NoneStrategies struct {
-	evict *Node
+type nonePolicy struct {
+	evict *node
 }
 
-func (s NoneStrategies) OnInsert(node *Node) {
+func (s nonePolicy) OnInsert(node *node) {
 	node.EvictPrev = s.evict
 	node.EvictNext = node.EvictPrev.EvictNext
 	node.EvictNext.EvictPrev = node
 	node.EvictPrev.EvictNext = node
 }
 
-func (NoneStrategies) OnAccess(n *Node) {
+func (nonePolicy) OnAccess(n *node) {
 }
 
-func (NoneStrategies) Evict() *Node {
+func (nonePolicy) Evict() *node {
 	return nil
 }
 
-type FIFOStrategies struct {
-	evict *Node
+type fifoPolicy struct {
+	evict *node
 }
 
-func (s FIFOStrategies) OnInsert(node *Node) {
+func (s fifoPolicy) OnInsert(node *node) {
 	node.EvictPrev = s.evict
 	node.EvictNext = node.EvictPrev.EvictNext
 	node.EvictNext.EvictPrev = node
 	node.EvictPrev.EvictNext = node
 }
 
-func (FIFOStrategies) OnAccess(n *Node) {
+func (fifoPolicy) OnAccess(n *node) {
 }
 
-func (s FIFOStrategies) Evict() *Node {
-	return s.evict.EvictPrev
+func (s fifoPolicy) Evict() *node {
+	if s.evict.EvictPrev != s.evict {
+		return s.evict.EvictPrev
+	} else {
+		return nil
+	}
 }
 
-type LRUStrategies struct {
-	evict *Node
+type lruPolicy struct {
+	evict *node
 }
 
-func (s LRUStrategies) OnInsert(node *Node) {
+func (s lruPolicy) OnInsert(node *node) {
+	node.EvictPrev = s.evict
+	node.EvictNext = node.EvictPrev.EvictNext
+	node.EvictNext.EvictPrev = node
+	node.EvictPrev.EvictNext = node
 }
 
-func (s LRUStrategies) OnAccess(node *Node) {
+func (s lruPolicy) OnAccess(node *node) {
 	node.EvictNext.EvictPrev = node.EvictPrev
 	node.EvictPrev.EvictNext = node.EvictNext
 
@@ -96,36 +108,43 @@ func (s LRUStrategies) OnAccess(node *Node) {
 	node.EvictPrev.EvictNext = node
 }
 
-func (s LRUStrategies) Evict() *Node {
-	return s.evict.EvictPrev
+func (s lruPolicy) Evict() *node {
+	if s.evict.EvictPrev != s.evict {
+		return s.evict.EvictPrev
+	} else {
+		return nil
+	}
 }
 
-type LFUStrategies struct {
-	evict *Node
+type lfuPolicy struct {
+	evict *node
 }
 
-func (s LFUStrategies) OnInsert(node *Node) {
+func (s lfuPolicy) OnInsert(node *node) {
 	node.EvictPrev = s.evict
 	node.EvictNext = node.EvictPrev.EvictNext
 	node.EvictNext.EvictPrev = node
 	node.EvictPrev.EvictNext = node
+	node.Access = 0
 }
 
-func (s LFUStrategies) OnAccess(node *Node) {
-	node.Access += 1
+func (s lfuPolicy) OnAccess(node *node) {
+	node.Access++
 
-	node.EvictNext.EvictPrev = node.EvictPrev
-	node.EvictPrev.EvictNext = node.EvictNext
+	for v := node.EvictPrev; v.EvictPrev != s.evict; v = v.EvictPrev {
+		if v.Access <= node.Access {
+			node.EvictNext.EvictPrev = node.EvictPrev
+			node.EvictPrev.EvictNext = node.EvictNext
 
-	for v := node.EvictPrev; v != s.evict; v = v.EvictPrev {
-		if v.Access >= node.Access {
 			node.EvictPrev = v
 			node.EvictNext = node.EvictPrev.EvictNext
 			node.EvictNext.EvictPrev = node
 			node.EvictPrev.EvictNext = node
-			break
+			return
 		}
 	}
+	node.EvictNext.EvictPrev = node.EvictPrev
+	node.EvictPrev.EvictNext = node.EvictNext
 
 	node.EvictPrev = s.evict
 	node.EvictNext = node.EvictPrev.EvictNext
@@ -133,6 +152,10 @@ func (s LFUStrategies) OnAccess(node *Node) {
 	node.EvictPrev.EvictNext = node
 }
 
-func (s LFUStrategies) Evict() *Node {
-	return s.evict.EvictPrev
+func (s lfuPolicy) Evict() *node {
+	if s.evict.EvictPrev != s.evict {
+		return s.evict.EvictPrev
+	} else {
+		return nil
+	}
 }