diff --git a/a8/orderbuffer.cc b/a8/orderbuffer.cc
index f78fb9c..0b9f60b 100644
--- a/a8/orderbuffer.cc
+++ b/a8/orderbuffer.cc
@@ -23,7 +23,10 @@ namespace a8
 
     char* OrderBuffer::Alloc(int len)
     {
-
+        if (len <= 0) {
+            abort();
+        }
+        int real_len = len + 4;
     }
 
     void OrderBuffer::Free(char* p)
diff --git a/a8/orderbuffer.h b/a8/orderbuffer.h
index d1923a4..eb87d94 100644
--- a/a8/orderbuffer.h
+++ b/a8/orderbuffer.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <atomic>
+
 namespace a8
 {
 
@@ -14,8 +16,12 @@ namespace a8
         void Free(char* p);
 
     private:
+
         char* buf_ = nullptr;
         int buf_len_ = 0;
+        std::atomic<int> start_ = 0;
+        std::atomic<int> end_ = 0;
+
     };
 
 }