X-Git-Url: https://gerrit.akraino.org/r/gitweb?a=blobdiff_plain;f=src%2Ffoundation%2Fapi%2Frevel%2Futils%2Fsimplestack.go;fp=src%2Ffoundation%2Fapi%2Frevel%2Futils%2Fsimplestack.go;h=bb22430b05dd3603fc4a5736ec6fd64d348e850f;hb=1d1ee6961c93781e1187d8c7faa868da6b2f01f4;hp=0000000000000000000000000000000000000000;hpb=56dd5e0f2164b37b40ac1daa188ccc618b4cbd19;p=iec.git

diff --git a/src/foundation/api/revel/utils/simplestack.go b/src/foundation/api/revel/utils/simplestack.go
new file mode 100644
index 0000000..bb22430
--- /dev/null
+++ b/src/foundation/api/revel/utils/simplestack.go
@@ -0,0 +1,103 @@
+package utils
+
+import (
+	"fmt"
+	"sync"
+)
+
+type (
+	SimpleLockStack struct {
+		Current  *SimpleLockStackElement
+		Creator  func() interface{}
+		len      int
+		capacity int
+		active   int
+		maxsize  int
+		lock     sync.Mutex
+	}
+	SimpleLockStackElement struct {
+		Value    interface{}
+		Previous *SimpleLockStackElement
+		Next     *SimpleLockStackElement
+	}
+	ObjectDestroy interface {
+		Destroy()
+	}
+)
+
+func NewStackLock(startsize, maxsize int, creator func() interface{}) *SimpleLockStack {
+	ss := &SimpleLockStack{lock: sync.Mutex{}, Current: &SimpleLockStackElement{Value: creator()}, Creator: creator, maxsize: maxsize}
+	if startsize > 0 {
+		elements := make([]SimpleLockStackElement, startsize-1)
+		current := ss.Current
+		for i := range elements {
+			e := elements[i]
+			if creator != nil {
+				e.Value = creator()
+			}
+			current.Next = &e
+			e.Previous = current
+			current = &e
+		}
+		ss.capacity, ss.len, ss.active = startsize, startsize, 0
+
+		ss.Current = current
+	}
+	return ss
+}
+func (s *SimpleLockStack) Pop() (value interface{}) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	if s.len == 0 {
+		// Pool is empty, create a new item to return
+		if s.Creator != nil {
+			value = s.Creator()
+		}
+	} else {
+		value = s.Current.Value
+		s.len--
+		if s.Current.Previous != nil {
+			s.Current = s.Current.Previous
+		}
+	}
+	// println("Pop ",value, s.len, s.active, s.capacity, s.Current.Next)
+	s.active++
+	return
+}
+func (s *SimpleLockStack) Push(value interface{}) {
+	if d, ok := value.(ObjectDestroy); ok {
+		d.Destroy()
+	}
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	if s.len == 0 {
+		s.Current.Value = value
+	} else if s.len < s.maxsize {
+		if s.Current.Next == nil {
+			s.Current.Next = &SimpleLockStackElement{Value: value, Previous: s.Current}
+			s.capacity++
+		} else {
+			s.Current.Next.Value = value
+		}
+		s.Current = s.Current.Next
+	} else {
+		// If we exceeded the capacity of stack do not store the created object
+		return
+	}
+	s.len++
+	s.active--
+	//println("Push ",value, s.len, s.active, s.capacity)
+	return
+}
+func (s *SimpleLockStack) Len() int {
+	return s.len
+}
+func (s *SimpleLockStack) Capacity() int {
+	return s.capacity
+}
+func (s *SimpleLockStack) Active() int {
+	return s.active
+}
+func (s *SimpleLockStack) String() string {
+	return fmt.Sprintf("SS: Capacity:%d Active:%d Stored:%d", s.capacity, s.active, s.len)
+}