/**
buffer for double
 */
type DoubleBuffer struct {
	index  int32
	buffer []float64
	isFull bool
}

func NewDoubleBuffer(size int32) *DoubleBuffer {
	return &DoubleBuffer{
		buffer:make([]float64, size),
	}
}

func (b *DoubleBuffer) Reset() {
	b.index = 0
	b.isFull = false
}

func (b *DoubleBuffer) IsFull() bool {
	return b.isFull
}

func (b *DoubleBuffer) GetAverage() float64 {
	entriesNum := 0
	if b.isFull {
		entriesNum = len(b.buffer)
	} else {
		entriesNum = int(b.index)
	}
	if entriesNum == 0 {
		return 0
	}
	sum := 0.0
	for i := 0; i < entriesNum; i++ {
		sum += b.buffer[i]
	}
	return sum / float64(entriesNum)
}

func (b *DoubleBuffer) Put(v float64) {
	if int32(len(b.buffer)) == b.index {
		b.index = 0
	}
	b.buffer[b.index] = v
	b.index++
	if b.index == int32(len(b.buffer)) {
		b.isFull = true
	}
}