From 31dae8140527295d30195637ac2376426f33dd7f Mon Sep 17 00:00:00 2001
From: Chris Ross <Tratcher@Outlook.com>
Date: Mon, 6 Apr 2015 11:56:27 -0700
Subject: [PATCH] Short circuit empty inputs.

---
 src/Microsoft.AspNet.WebUtilities/WebEncoders.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Microsoft.AspNet.WebUtilities/WebEncoders.cs b/src/Microsoft.AspNet.WebUtilities/WebEncoders.cs
index 2a559d0ec9..de801b29d4 100644
--- a/src/Microsoft.AspNet.WebUtilities/WebEncoders.cs
+++ b/src/Microsoft.AspNet.WebUtilities/WebEncoders.cs
@@ -41,6 +41,12 @@ namespace Microsoft.AspNet.WebUtilities
         {
             ValidateParameters(input.Length, offset, count);
 
+            // Special-case empty input
+            if (count == 0)
+            {
+                return new byte[0];
+            }
+
             // Assumption: input is base64url encoded without padding and contains no whitespace.
 
             // First, we need to add the padding characters back.