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galene/estimator/estimator.go
2020-05-03 11:06:08 +02:00

54 lines
880 B
Go

package estimator
import (
"sync"
"sync/atomic"
"time"
)
type Estimator struct {
interval time.Duration
count uint32
mu sync.Mutex
rate uint32
time time.Time
}
func New(interval time.Duration) *Estimator {
return &Estimator{
interval: interval,
time: time.Now(),
}
}
func (e *Estimator) swap(now time.Time) {
interval := now.Sub(e.time)
count := atomic.SwapUint32(&e.count, 0)
if interval < time.Millisecond {
e.rate = 0
} else {
e.rate = uint32(uint64(count*1000) / uint64(interval/time.Millisecond))
}
e.time = now
}
func (e *Estimator) Add(count uint32) {
atomic.AddUint32(&e.count, count)
}
func (e *Estimator) estimate(now time.Time) uint32 {
if now.Sub(e.time) > e.interval {
e.swap(now)
}
return e.rate
}
func (e *Estimator) Estimate() uint32 {
now := time.Now()
e.mu.Lock()
defer e.mu.Unlock()
return e.estimate(now)
}