serialize dynamically sized Eigen matrices

- use index based access to avoid buffer

assembly/src/include/ae108/assembly/utilities/serialize.h

@@ -68,12 +68,13 @@ OutputIterator serialize(const std::vector<ValueType> &vector,
 template <class OutputIterator, class ValueType, int Rows, int Cols>
 OutputIterator serialize(const Eigen::Matrix<ValueType, Rows, Cols> &vector,
                          OutputIterator bufferBegin) {
-  std::array<ValueType, Rows * Cols> buffer;
-  Eigen::Map<Eigen::Matrix<ValueType, Rows, Cols,
-                           Cols == 1 ? Eigen::ColMajor : Eigen::RowMajor>>
-      wrappedBuffer(buffer.data(), vector.rows(), vector.cols());
-  wrappedBuffer = vector;
-  return std::copy(buffer.begin(), buffer.end(), bufferBegin);
+  for (Eigen::Index i = 0; i < vector.rows(); ++i) {
+    for (Eigen::Index j = 0; j < vector.cols(); ++j) {
+      *bufferBegin = vector(i, j);
+      bufferBegin++;
+    }
+  }
+  return bufferBegin;
 }
 
 /**

assembly/test/serialize_Test.cc

@@ -69,6 +69,20 @@ TEST_F(serialize_Test, serializing_eigen_matrix_works) {
                                   DoubleEq(0.)));
 }
 
+TEST_F(serialize_Test, serializing_dynamically_sized_eigen_matrix_works) {
+  Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic> values(3, 2);
+  values << 1, 2, 3, 4, 5, 6;
+  std::vector<double> buffer(7);
+
+  const auto result = serialize(values, buffer.begin());
+
+  EXPECT_THAT(result, Eq(buffer.begin() + 6));
+
+  EXPECT_THAT(buffer, ElementsAre(DoubleEq(1.), DoubleEq(2.), DoubleEq(3.),
+                                  DoubleEq(4.), DoubleEq(5.), DoubleEq(6.),
+                                  DoubleEq(0.)));
+}
+
 TEST_F(serialize_Test, serializing_eigen_vector_works) {
   Eigen::Vector3d values;
   values << 1, 2, 3;