Compile time BitLenToByteLen computation; marshal type util tests

libuavcan/include/uavcan/internal/marshal/type_util.hpp

@@ -20,6 +20,10 @@ template <>
 struct IntegerBitLen<0> { enum { Result = 0 }; };
 
 
+template <unsigned long BitLen>
+struct BitLenToByteLen { enum { Result = (BitLen + 7) / 8 }; };
+
+
 template <typename T, typename Enable = void>
 struct StorageType { typedef T Type; };
 

libuavcan/include/uavcan/publisher.hpp

@@ -12,6 +12,7 @@
 #include <uavcan/internal/lazy_constructor.hpp>
 #include <uavcan/internal/transport/transfer_sender.hpp>
 #include <uavcan/internal/marshal/scalar_codec.hpp>
+#include <uavcan/internal/marshal/types.hpp>
 
 namespace uavcan
 {
@@ -54,8 +55,7 @@ private:
 
     IMarshalBuffer* getBuffer()
     {
-        const int size = (DataType::MaxBitLen + 7) / 8;
-        return buffer_provider_.getBuffer(size);
+        return buffer_provider_.getBuffer(BitLenToByteLen<DataType::MaxBitLen>::Result);
     }
 
     int genericSend(const DataType& message, TransferType transfer_type, NodeID dst_node_id,

libuavcan/test/marshal/array.cpp

@@ -76,18 +76,6 @@ struct CustomType
 };
 
 
-TEST(Array, IntegerBitLen)
-{
-    using uavcan::IntegerBitLen;
-
-    ASSERT_EQ(0, IntegerBitLen<0>::Result);
-    ASSERT_EQ(1, IntegerBitLen<1>::Result);
-    ASSERT_EQ(6, IntegerBitLen<42>::Result);
-    ASSERT_EQ(8, IntegerBitLen<232>::Result);
-    ASSERT_EQ(32, IntegerBitLen<0x81234567>::Result);
-}
-
-
 TEST(Array, Basic)
 {
     typedef Array<IntegerSpec<8, SignednessSigned, CastModeTruncate>, ArrayModeStatic, 4> A1;

libuavcan/test/marshal/type_util.cpp

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#include <gtest/gtest.h>
+#include <uavcan/internal/marshal/types.hpp>
+
+
+TEST(MarshalTypeUtil, IntegerBitLen)
+{
+    using uavcan::IntegerBitLen;
+
+    ASSERT_EQ(0, IntegerBitLen<0>::Result);
+    ASSERT_EQ(1, IntegerBitLen<1>::Result);
+    ASSERT_EQ(6, IntegerBitLen<42>::Result);
+    ASSERT_EQ(8, IntegerBitLen<232>::Result);
+    ASSERT_EQ(32, IntegerBitLen<0x81234567>::Result);
+}
+
+
+TEST(MarshalTypeUtil, BitLenToByteLen)
+{
+    using uavcan::BitLenToByteLen;
+
+    ASSERT_EQ(2, BitLenToByteLen<16>::Result);
+    ASSERT_EQ(1, BitLenToByteLen<8>::Result);
+    ASSERT_EQ(1, BitLenToByteLen<7>::Result);
+    ASSERT_EQ(1, BitLenToByteLen<1>::Result);
+    ASSERT_EQ(2, BitLenToByteLen<9>::Result);
+}