✨ Attachment has pool

pkg/internal/services/random_id.go

@@ -0,0 +1,31 @@
+package services
+
+import (
+	"math/rand"
+	"strings"
+)
+
+const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+const (
+	letterIdxBits = 6
+	letterIdxMask = 1<<letterIdxBits - 1
+	letterIdxMax  = 63 / letterIdxBits
+)
+
+func RandString(length int) string {
+	builder := strings.Builder{}
+	builder.Grow(length)
+	for idx, cache, remain := length-1, rand.Int63(), letterIdxMax; idx >= 0; {
+		if remain == 0 {
+			cache, remain = rand.Int63(), letterIdxMax
+		}
+		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
+			builder.WriteByte(letterBytes[idx])
+			idx--
+		}
+		cache >>= letterIdxBits
+		remain--
+	}
+
+	return builder.String()
+}