intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 78 insertions, 0 deletions

diff --git a/library/cpp/messagebus/left_right_buffer.h b/library/cpp/messagebus/left_right_buffer.h
new file mode 100644
index 0000000000..f937cefad0
--- /dev/null
+++ b/library/cpp/messagebus/left_right_buffer.h
@@ -0,0 +1,78 @@
+#pragma once
+
+#include <util/generic/buffer.h>
+#include <util/generic/noncopyable.h>
+#include <util/system/yassert.h>
+
+namespace NBus {
+    namespace NPrivate {
+        class TLeftRightBuffer : TNonCopyable {
+        private:
+            TBuffer Buffer;
+            size_t Left;
+
+            void CheckInvariant() {
+                Y_ASSERT(Left <= Buffer.Size());
+            }
+
+        public:
+            TLeftRightBuffer()
+                : Left(0)
+            {
+            }
+
+            TBuffer& GetBuffer() {
+                return Buffer;
+            }
+
+            size_t Capacity() {
+                return Buffer.Capacity();
+            }
+
+            void Clear() {
+                Buffer.Clear();
+                Left = 0;
+            }
+
+            void Reset() {
+                Buffer.Reset();
+                Left = 0;
+            }
+
+            void Compact() {
+                Buffer.ChopHead(Left);
+                Left = 0;
+            }
+
+            char* LeftPos() {
+                return Buffer.Data() + Left;
+            }
+
+            size_t LeftSize() {
+                return Left;
+            }
+
+            void LeftProceed(size_t count) {
+                Y_ASSERT(count <= Size());
+                Left += count;
+            }
+
+            size_t Size() {
+                return Buffer.Size() - Left;
+            }
+
+            bool Empty() {
+                return Size() == 0;
+            }
+
+            char* RightPos() {
+                return Buffer.Data() + Buffer.Size();
+            }
+
+            size_t Avail() {
+                return Buffer.Avail();
+            }
+        };
+
+    }
+}