Initial commit

lib/idgen/gen.go

@@ -0,0 +1,32 @@
+package idgen
+
+import (
+	"sync"
+	"time"
+)
+
+var (
+	lock       sync.Mutex
+	ts         uint64 = uint64(time.Now().Unix())
+	counter    uint64 = 1
+	counterMax uint64 = 1 << 28
+)
+
+// Next can generate ~268M ints per second for ~1000 years.
+func Next() uint64 {
+	lock.Lock()
+	defer lock.Unlock()
+
+	tt := uint64(time.Now().Unix())
+	if tt > ts {
+		ts = tt
+		counter = 1
+	} else {
+		counter++
+		if counter == counterMax {
+			panic("Too many IDs.")
+		}
+	}
+
+	return ts<<28 + counter
+}

lib/idgen/gen_test.go

@@ -0,0 +1,11 @@
+package idgen
+
+import (
+	"testing"
+)
+
+func BenchmarkNext(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Next()
+	}
+}