New cpp folder structure

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

libs/indexer/dat_section_header.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include "coding/reader.hpp"
+
+namespace feature
+{
+struct DatSectionHeader
+{
+public:
+  enum class Version : uint8_t
+  {
+    V0 = 0,
+    Latest = V0
+  };
+
+  template <typename Sink>
+  void Serialize(Sink & sink) const
+  {
+    CHECK_EQUAL(m_version, Version::V0, ());
+    WriteToSink(sink, static_cast<uint8_t>(m_version));
+    WriteToSink(sink, m_featuresOffset);
+    WriteToSink(sink, m_featuresSize);
+  }
+
+  void Read(Reader & reader)
+  {
+    NonOwningReaderSource source(reader);
+    m_version = static_cast<Version>(ReadPrimitiveFromSource<uint8_t>(source));
+    CHECK_EQUAL(static_cast<uint8_t>(m_version), static_cast<uint8_t>(Version::V0), ());
+    m_featuresOffset = ReadPrimitiveFromSource<uint32_t>(source);
+    m_featuresSize = ReadPrimitiveFromSource<uint32_t>(source);
+  }
+
+  Version m_version = Version::Latest;
+  // All offsets are relative to the start of the section (offset of header is zero).
+  uint32_t m_featuresOffset = 0;
+  uint32_t m_featuresSize = 0;
+};
+
+inline std::string DebugPrint(DatSectionHeader::Version v)
+{
+  CHECK(v == DatSectionHeader::Version::V0, ());
+  return "V0";
+}
+}  // namespace feature