From ea6982fceaffb3e460771bc2a5c5e7f2379de9a5 Mon Sep 17 00:00:00 2001
From: astaxie <xiemengjun@gmail.com>
Date: Tue, 5 Aug 2014 23:52:06 +0800
Subject: [PATCH] beego: template fund when the start> len(bt)

---
 templatefunc.go      | 3 +++
 templatefunc_test.go | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/templatefunc.go b/templatefunc.go
index da1ebc56..f72017e1 100644
--- a/templatefunc.go
+++ b/templatefunc.go
@@ -27,6 +27,9 @@ func Substr(s string, start, length int) string {
 	if start < 0 {
 		start = 0
 	}
+	if start > len(bt) {
+		start = start % len(bt)
+	}
 	var end int
 	if (start + length) > (len(bt) - 1) {
 		end = len(bt)
diff --git a/templatefunc_test.go b/templatefunc_test.go
index fabbb431..49807f12 100644
--- a/templatefunc_test.go
+++ b/templatefunc_test.go
@@ -25,6 +25,9 @@ func TestSubstr(t *testing.T) {
 	if Substr(s, 0, 100) != "012345" {
 		t.Error("should be equal")
 	}
+	if Substr(s, 12, 100) != "012345" {
+		t.Error("should be equal")
+	}
 }
 
 func TestHtml2str(t *testing.T) {