Initial QSfera import

Server/vendor/github.com/bluele/gcache/stats.go

@@ -0,0 +1,53 @@
+package gcache
+
+import (
+	"sync/atomic"
+)
+
+type statsAccessor interface {
+	HitCount() uint64
+	MissCount() uint64
+	LookupCount() uint64
+	HitRate() float64
+}
+
+// statistics
+type stats struct {
+	hitCount  uint64
+	missCount uint64
+}
+
+// increment hit count
+func (st *stats) IncrHitCount() uint64 {
+	return atomic.AddUint64(&st.hitCount, 1)
+}
+
+// increment miss count
+func (st *stats) IncrMissCount() uint64 {
+	return atomic.AddUint64(&st.missCount, 1)
+}
+
+// HitCount returns hit count
+func (st *stats) HitCount() uint64 {
+	return atomic.LoadUint64(&st.hitCount)
+}
+
+// MissCount returns miss count
+func (st *stats) MissCount() uint64 {
+	return atomic.LoadUint64(&st.missCount)
+}
+
+// LookupCount returns lookup count
+func (st *stats) LookupCount() uint64 {
+	return st.HitCount() + st.MissCount()
+}
+
+// HitRate returns rate for cache hitting
+func (st *stats) HitRate() float64 {
+	hc, mc := st.HitCount(), st.MissCount()
+	total := hc + mc
+	if total == 0 {
+		return 0.0
+	}
+	return float64(hc) / float64(total)
+}