add missing stats/counter.go file

stats/counter.go

@@ -0,0 +1,86 @@
+package stats
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type ElementCount struct {
+	Current int64
+	Total   int64
+	Rps     float64
+	LastRps float64
+}
+
+func NewRpsCounter() *RpsCounter {
+	return &RpsCounter{
+		mu: &sync.Mutex{},
+	}
+}
+
+type RpsCounter struct {
+	counter int64
+	lastAdd int64
+	start   time.Time
+	stop    time.Time
+	updated bool
+	mu      *sync.Mutex
+	total   int64
+}
+
+func (r *RpsCounter) Add(n int) {
+	atomic.AddInt64(&r.counter, int64(n))
+	atomic.AddInt64(&r.lastAdd, int64(n))
+	if n > 0 {
+		r.mu.Lock()
+		defer r.mu.Unlock()
+		if r.start.IsZero() {
+			r.start = time.Now()
+		}
+		r.updated = true
+	}
+}
+
+func (r *RpsCounter) Value() int64 {
+	return atomic.LoadInt64(&r.counter)
+}
+
+func (r *RpsCounter) Rps() float64 {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return float64(atomic.LoadInt64(&r.counter)) / float64(r.stop.Sub(r.start).Seconds())
+}
+
+func (r *RpsCounter) LastRps() float64 {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return float64(atomic.LoadInt64(&r.lastAdd)) / float64(time.Since(r.stop).Seconds())
+}
+
+func (r *RpsCounter) Progress() float64 {
+	if r.total == 0 {
+		return -1.0
+	}
+
+	return float64(atomic.LoadInt64(&r.counter)) / float64(r.total)
+}
+
+func (r *RpsCounter) Count() ElementCount {
+	return ElementCount{
+		Current: r.Value(),
+		Total:   r.total,
+		Rps:     r.Rps(),
+		LastRps: r.LastRps(),
+	}
+}
+
+func (r *RpsCounter) Tick() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.updated {
+		r.stop = time.Now()
+		r.updated = false
+	}
+	atomic.StoreInt64(&r.lastAdd, 0)
+}