New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/indexer/complex/serdes_utils.hpp

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "coding/reader.hpp"
+#include "coding/varint.hpp"
+
+#include "base/assert.hpp"
+#include "base/checked_cast.hpp"
+
+namespace coding_utils
+{
+// Type of collection size. Used for reading and writing collections.
+using CollectionSizeType = uint64_t;
+
+// WriteCollectionPrimitive writes collection. It uses WriteToSink function.
+template <typename Sink, typename Cont>
+void WriteCollectionPrimitive(Sink & sink, Cont const & container)
+{
+  auto const contSize = base::checked_cast<CollectionSizeType>(container.size());
+  WriteVarUint(sink, contSize);
+  for (auto value : container)
+    WriteToSink(sink, value);
+}
+
+// ReadCollectionPrimitive reads collection. It uses ReadPrimitiveFromSource function.
+template <typename Source, typename OutIt>
+void ReadCollectionPrimitive(Source & src, OutIt it)
+{
+  using ValueType = typename OutIt::container_type::value_type;
+
+  auto size = ReadVarUint<CollectionSizeType>(src);
+  while (size--)
+    *it++ = ReadPrimitiveFromSource<ValueType>(src);
+}
+}  // namespace coding_utils