Drafted inplace_ring_buff.

jsexport/battle/inplace_ring_buff.go

@@ -0,0 +1,183 @@
+package battle
+
+import (
+	"resolv"
+)
+
+type InplaceRingBuffer struct {
+	Ed        int32 // write index, open index
+	St        int32 // read index, closed index
+	EdFrameId int32
+	StFrameId int32
+	N         int32
+	Cnt       int32 // the count of valid elements in the buffer, used mainly to distinguish what "st == ed" means for "Pop" and "Get" methods
+	Eles      []interface{}
+}
+
+func NewInplaceRingBuffer(n int32) *InplaceRingBuffer {
+	return &InplaceRingBuffer{
+		Ed:        0,
+		St:        0,
+		EdFrameId: 0,
+		StFrameId: 0,
+		N:         n,
+		Cnt:       0,
+		Eles:      make([]interface{}, n),
+	}
+}
+
+func (rb *InplaceRingBuffer) Put(pItem interface{}) {
+	switch pItem.(type) {
+	case *RoomDownsyncFrame:
+	default:
+		// Other types are not supported!
+		return
+	}
+	for 0 < rb.Cnt && rb.Cnt >= rb.N {
+		// Make room for the new element
+		rb.Pop(nil)
+	}
+	switch v := pItem.(type) {
+	case *RoomDownsyncFrame:
+		CloneRoomDownsyncFrame(v.Id, v.PlayersArr, v.BulletLocalIdCounter, v.MeleeBullets, v.FireballBullets, rb.Eles[rb.Ed].(*RoomDownsyncFrame))
+	}
+	rb.EdFrameId++
+	rb.Cnt++
+	rb.Ed++
+	if rb.Ed >= rb.N {
+		rb.Ed -= rb.N // Deliberately not using "%" operator for performance concern
+	}
+}
+
+func (rb *InplaceRingBuffer) Pop(holder interface{}) bool {
+	switch holder.(type) {
+	case *RoomDownsyncFrame, nil:
+	default:
+		// Other types are not supported!
+		return false
+	}
+	if 0 == rb.Cnt {
+		return false
+	}
+	switch u := holder.(type) {
+	case *RoomDownsyncFrame:
+		v := rb.Eles[rb.St].(*RoomDownsyncFrame)
+		CloneRoomDownsyncFrame(v.Id, v.PlayersArr, v.BulletLocalIdCounter, v.MeleeBullets, v.FireballBullets, u)
+		// If nil, there's no holder for output, I'm OK for that...
+	}
+	rb.StFrameId++
+	rb.Cnt--
+	rb.St++
+	if rb.St >= rb.N {
+		rb.St -= rb.N
+	}
+	return true
+}
+
+func (rb *InplaceRingBuffer) GetArrIdxByOffset(offsetFromSt int32) int32 {
+	if 0 == rb.Cnt || 0 > offsetFromSt {
+		return -1
+	}
+	arrIdx := rb.St + offsetFromSt
+	if rb.St < rb.Ed {
+		// case#1: 0...st...ed...N-1
+		if rb.St <= arrIdx && arrIdx < rb.Ed {
+			return arrIdx
+		}
+	} else {
+		// if rb.St >= rb.Ed
+		// case#2: 0...ed...st...N-1
+		if arrIdx >= rb.N {
+			arrIdx -= rb.N
+		}
+		if arrIdx >= rb.St || arrIdx < rb.Ed {
+			return arrIdx
+		}
+	}
+
+	return -1
+}
+
+func (rb *InplaceRingBuffer) GetByOffset(offsetFromSt int32, holder interface{}) bool {
+	switch holder.(type) {
+	case *RoomDownsyncFrame:
+	default:
+		// Other types are not supported!
+		return false
+	}
+	arrIdx := rb.GetArrIdxByOffset(offsetFromSt)
+	if -1 == arrIdx {
+		return false
+	}
+	switch u := holder.(type) {
+	case *RoomDownsyncFrame:
+		v := rb.Eles[arrIdx].(*RoomDownsyncFrame)
+		CloneRoomDownsyncFrame(v.Id, v.PlayersArr, v.BulletLocalIdCounter, v.MeleeBullets, v.FireballBullets, u)
+	}
+	return true
+}
+
+func (rb *InplaceRingBuffer) GetByFrameId(frameId int32, holder interface{}) bool {
+	switch holder.(type) {
+	case *RoomDownsyncFrame:
+	default:
+		// Other types are not supported!
+		return false
+	}
+	if frameId >= rb.EdFrameId || frameId < rb.StFrameId {
+		return false
+	}
+	return rb.GetByOffset(frameId-rb.StFrameId, holder)
+}
+
+// [WARNING] During a battle, frontend could receive non-consecutive frames (either renderFrame or inputFrame) due to resync, the buffer should handle these frames properly.
+func (rb *InplaceRingBuffer) SetByFrameId(pItem interface{}, frameId int32) (int32, int32, int32) {
+	oldStFrameId, oldEdFrameId := rb.StFrameId, rb.EdFrameId
+	switch pItem.(type) {
+	case *RoomDownsyncFrame:
+	default:
+		// Other types are not supported!
+		return resolv.RING_BUFF_FAILED_TO_SET, oldStFrameId, oldEdFrameId
+	}
+	if frameId < oldStFrameId {
+		return resolv.RING_BUFF_FAILED_TO_SET, oldStFrameId, oldEdFrameId
+	}
+	// By now "rb.StFrameId <= frameId"
+	if oldEdFrameId > frameId {
+		arrIdx := rb.GetArrIdxByOffset(frameId - rb.StFrameId)
+		if -1 != arrIdx {
+			switch v := pItem.(type) {
+			case *RoomDownsyncFrame:
+				CloneRoomDownsyncFrame(v.Id, v.PlayersArr, v.BulletLocalIdCounter, v.MeleeBullets, v.FireballBullets, rb.Eles[arrIdx].(*RoomDownsyncFrame))
+				return resolv.RING_BUFF_CONSECUTIVE_SET, oldStFrameId, oldEdFrameId
+			default:
+				// Other types are not supported!
+				return resolv.RING_BUFF_FAILED_TO_SET, oldStFrameId, oldEdFrameId
+			}
+		}
+	}
+
+	// By now "rb.EdFrameId <= frameId"
+	ret := resolv.RING_BUFF_CONSECUTIVE_SET
+	if oldEdFrameId < frameId {
+		rb.St, rb.Ed = 0, 0
+		rb.StFrameId, rb.EdFrameId = frameId, frameId
+		rb.Cnt = 0
+		ret = resolv.RING_BUFF_NON_CONSECUTIVE_SET
+	}
+
+	// By now "rb.EdFrameId == frameId"
+	rb.Put(pItem)
+
+	return ret, oldStFrameId, oldEdFrameId
+}
+
+func (rb *InplaceRingBuffer) Clear() {
+	for 0 < rb.Cnt {
+		rb.Pop(nil)
+	}
+	rb.St = 0
+	rb.Ed = 0
+	rb.StFrameId = 0
+	rb.EdFrameId = 0
+}