From edf4e91fc3df8936edfd7c3b6202783f96f7f3e4 Mon Sep 17 00:00:00 2001
From: Alexandre Mutel <alexandre@siliconstudio.co.jp>
Date: Wed, 24 Feb 2016 06:13:11 +0900
Subject: [PATCH] Improve performance of StringBuilderCache.Local()

---
 src/Textamina.Markdig/Helpers/StringBuilderCache.cs | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/Textamina.Markdig/Helpers/StringBuilderCache.cs b/src/Textamina.Markdig/Helpers/StringBuilderCache.cs
index 8f4cd382..a1b8ba4e 100644
--- a/src/Textamina.Markdig/Helpers/StringBuilderCache.cs
+++ b/src/Textamina.Markdig/Helpers/StringBuilderCache.cs
@@ -14,8 +14,12 @@ namespace Textamina.Markdig.Helpers
 
         public static StringBuilder Local()
         {
-            local.Clear();
-            return local;
+            var sb = local;
+            if (sb.Length > 0)
+            {
+                sb.Clear();
+            }
+            return sb;
         }
 
         private readonly Stack<StringBuilder> builders;
@@ -38,7 +42,10 @@ namespace Textamina.Markdig.Helpers
         public void Release(StringBuilder builder)
         {
             if (builder == null) throw new ArgumentNullException(nameof(builder));
-            builder.Clear();
+            if (builder.Length > 0)
+            {
+                builder.Clear();
+            }
             builders.Push(builder);
         }
     }