From 0acf1b976b2303361df0a0ffed4e29d4783b0495 Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Tue, 11 Feb 2014 21:44:43 +0400
Subject: [PATCH] Explicit specialization for empty TransferBuffer (for single
 frame transfers)

---
 .../internal/transport/transfer_buffer.hpp    | 33 ++++++++++++++++++-
 libuavcan/test/transport/transfer_buffer.cpp  |  8 +++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/libuavcan/include/uavcan/internal/transport/transfer_buffer.hpp b/libuavcan/include/uavcan/internal/transport/transfer_buffer.hpp
index b2f39faa2e..3fb166bf6a 100644
--- a/libuavcan/include/uavcan/internal/transport/transfer_buffer.hpp
+++ b/libuavcan/include/uavcan/internal/transport/transfer_buffer.hpp
@@ -335,7 +335,11 @@ class TransferBufferManager : public ITransferBufferManager, Noncopyable
 public:
     TransferBufferManager(IAllocator* allocator)
     : allocator_(allocator)
-    { }
+    {
+        assert(allocator);
+        StaticAssert<(MAX_BUF_SIZE > 0)>::check();
+        StaticAssert<(NUM_STATIC_BUFS > 0)>::check();
+    }
 
     ~TransferBufferManager()
     {
@@ -425,4 +429,31 @@ public:
     }
 };
 
+template <>
+class TransferBufferManager<0, 0> : public ITransferBufferManager
+{
+public:
+    TransferBufferManager(IAllocator* allocator)
+    {
+        (void)allocator;
+    }
+
+    TransferBufferBase* access(const TransferBufferManagerKey& key)
+    {
+        (void)key;
+        return NULL;
+    }
+
+    TransferBufferBase* create(const TransferBufferManagerKey& key)
+    {
+        (void)key;
+        return NULL;
+    }
+
+    void remove(const TransferBufferManagerKey& key)
+    {
+        (void)key;
+    }
+};
+
 }
diff --git a/libuavcan/test/transport/transfer_buffer.cpp b/libuavcan/test/transport/transfer_buffer.cpp
index 6107fb783e..8c9e1278c7 100644
--- a/libuavcan/test/transport/transfer_buffer.cpp
+++ b/libuavcan/test/transport/transfer_buffer.cpp
@@ -338,3 +338,11 @@ TEST(TransferBufferManager, Basic)
     mgr.reset();
     ASSERT_EQ(0, pool.getNumUsedBlocks());
 }
+
+
+TEST(TransferBufferManager, EmptySpecialization)
+{
+    uavcan::TransferBufferManager<0, 0> mgr(NULL);
+    (void)mgr;
+    ASSERT_GE(sizeof(void*), sizeof(mgr));
+}