Initial commit.

go.mod

@@ -0,0 +1,3 @@
+module git.crumpinton.com/lib/idgen
+
+go 1.25.1

idgen.go

@@ -0,0 +1,53 @@
+package idgen
+
+import (
+	"crypto/rand"
+	"encoding/base32"
+	"sync"
+	"time"
+)
+
+// Creates a new, random token.
+func NewToken() string {
+	buf := make([]byte, 20)
+	_, err := rand.Read(buf)
+	if err != nil {
+		panic(err)
+	}
+	return base32.StdEncoding.EncodeToString(buf)
+}
+
+var (
+	lock       sync.Mutex
+	ts         int64 = time.Now().Unix()
+	counter    int64 = 1
+	counterMax int64 = 1 << 20
+)
+
+// NextID can generate ~1M ints per second for a given nodeID.
+//
+// nodeID must be less than 64.
+func NextID(nodeID int64) int64 {
+	lock.Lock()
+	defer lock.Unlock()
+
+	tt := time.Now().Unix()
+	if tt > ts {
+		ts = tt
+		counter = 1
+	} else {
+		counter++
+		if counter == counterMax {
+			panic("Too many IDs.")
+		}
+	}
+
+	return (ts << 26) + (nodeID << 20) + counter
+}
+
+func SplitID(id int64) (unixTime, nodeID, counter int64) {
+	counter = id & (0x00000000000FFFFF)
+	nodeID = (id >> 20) & (0x000000000000003F)
+	unixTime = id >> 26
+	return
+}

idgen_test.go

@@ -0,0 +1,19 @@
+package idgen
+
+import (
+	"log"
+	"testing"
+)
+
+func BenchmarkNext(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		NextID(0)
+	}
+}
+
+func TestNextID(t *testing.T) {
+	id := NextID(32)
+
+	a, b, c := SplitID(id)
+	log.Print(a, b, c)
+}