rand

rands/rand.go

@@ -1,8 +1,8 @@
 package rands
 
 import (
+	"github.com/pyihe/go-pkg/bytes"
 	"math/rand"
-	"strings"
 	"time"
 )
 
@@ -13,8 +13,13 @@ const (
 	letterIdxMax  = 63 / letterIdxBits
 )
 
+var (
+	src rand.Source
+)
+
 func init() {
 	rand.Seed(time.Now().UnixNano())
+	src = rand.NewSource(time.Now().UnixNano())
 }
 
 //生成min-max之间的一个随机数
@@ -26,20 +31,18 @@ func Int(min, max int) int {
 }
 
 //随机指定长度的字符串
-func String(n uint) string {
-	sb := strings.Builder{}
-	sb.Grow(int(n))
-
-	for i, cache, remain := n-1, rand.Int63(), letterIdxMax; i >= 0; {
+func String(n int) string {
+	var b = make([]byte, n)
+	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
 		if remain == 0 {
-			cache, remain = rand.Int63(), letterIdxMax
+			cache, remain = src.Int63(), letterIdxMax
 		}
 		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
-			sb.WriteByte(letterBytes[idx])
+			b[i] = letterBytes[idx]
 			i--
 		}
 		cache >>= letterIdxBits
 		remain--
 	}
-	return sb.String()
+	return bytes.String(b)
 }