Update package rate

Author: mohanson

lib/rate/rate.go

@@ -19,30 +19,16 @@ type Limits struct {
 	step     time.Duration
 }
 
-// Peek glances there are enough resources (n) available.
-func (l *Limits) Peek(n uint64) bool {
-	l.mu.Lock()
-	defer l.mu.Unlock()
-	cycles := uint64(time.Since(l.last) / l.step)
-	if cycles > 0 {
-		l.last = l.last.Add(l.step * time.Duration(cycles))
-		if cycles > math.MaxUint64/l.addition {
-			log.Panicln("rate: overflow")
-		}
-		if l.size > math.MaxUint64-l.addition*cycles {
-			log.Panicln("rate: overflow")
-		}
-		l.size = l.size + l.addition*cycles
-		l.size = min(l.size, l.capacity)
-	}
-	return l.size >= n
-}
-
 // Wait ensures there are enough resources (n) available, blocking if necessary.
 func (l *Limits) Wait(n uint64) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
-	cycles := uint64(time.Since(l.last) / l.step)
+	curr := time.Now()
+	if curr.Before(l.last) {
+		l.last = curr
+	}
+	diff := curr.Sub(l.last)
+	cycles := uint64(diff / l.step)
 	if cycles > 0 {
 		l.last = l.last.Add(l.step * time.Duration(cycles))
 		if cycles > math.MaxUint64/l.addition {