From 75039c573cf662611d9dcee40ac0f49f87b44493 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Mon, 3 Oct 2016 22:04:32 +0900
Subject: [PATCH] base64: Assert that input is multiple of 4

---
 src/base64.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/base64.h b/src/base64.h
index c173a5a5..c8b16e8c 100644
--- a/src/base64.h
+++ b/src/base64.h
@@ -108,7 +108,7 @@ OutputIt decode(InputIt first, InputIt last, OutputIt d_first) {
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1};
-
+  assert(std::distance(first, last) % 4 == 0);
   auto p = d_first;
   for (; first != last;) {
     uint32_t n = 0;