update

stringx/mask.go

@@ -0,0 +1,40 @@
+package stringx
+
+import (
+	"strings"
+)
+
+type Place int
+
+const (
+	Begin Place = iota
+	Middle
+	End
+)
+
+func Mask(s string, place Place, length int, mask ...rune) string {
+	m := '*'
+	if len(mask) > 0 {
+		m = mask[0]
+	}
+
+	n := len(s)
+	if length >= n {
+		return strings.Repeat(string(m), n)
+	}
+
+	i := 0
+	if place == Middle {
+		i = (n - length) / 2
+	} else if place == End {
+		i = n - length
+	}
+
+	end := i + length
+	r := []rune(s)
+	for ; i < end; i++ {
+		r[i] = m
+	}
+
+	return string(r)
+}