From d68c9517953ac1de6472ccb03b547aacacedf53f Mon Sep 17 00:00:00 2001
From: Stephen Chung <Stephen.Chung@intexact.com>
Date: Sun, 18 Oct 2020 22:47:58 +0800
Subject: [PATCH] Pad string to exact length even when padding string is not
 multiple.

---
 src/fn_native.rs            | 2 +-
 src/packages/string_more.rs | 9 +++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/fn_native.rs b/src/fn_native.rs
index 113f19a1..8a3c9a1d 100644
--- a/src/fn_native.rs
+++ b/src/fn_native.rs
@@ -49,7 +49,7 @@ pub type Locked<T> = RefCell<T>;
 #[cfg(feature = "sync")]
 pub type Locked<T> = RwLock<T>;
 
-/// Context of a script evaluation process.
+/// Context of native Rust function call.
 #[derive(Debug, Copy, Clone)]
 pub struct NativeCallContext<'e, 'm> {
     engine: &'e Engine,
diff --git a/src/packages/string_more.rs b/src/packages/string_more.rs
index cd71fd41..06217d11 100644
--- a/src/packages/string_more.rs
+++ b/src/packages/string_more.rs
@@ -324,8 +324,13 @@ mod string_functions {
                 let p = s.make_mut();
 
                 while str_len < len as usize {
-                    p.push_str(padding);
-                    str_len += padding_len;
+                    if str_len + padding_len <= len as usize {
+                        p.push_str(padding);
+                        str_len += padding_len;
+                    } else {
+                        p.extend(padding.chars().take(len as usize - str_len));
+                        str_len = len as usize;
+                    }
                 }
 
                 #[cfg(not(feature = "unchecked"))]