New cpp folder structure

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

libs/indexer/feature_impl.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include "indexer/scales.hpp"
+
+#include "base/assert.hpp"
+
+#include <string>
+
+namespace strings { class UniString; }
+
+namespace feature
+{
+int constexpr g_arrWorldScales[] = { 3, 5, 7, scales::GetUpperWorldScale() };
+int constexpr g_arrCountryScales[] = { 10, 12, 14, scales::GetUpperScale() };
+static_assert(std::size(g_arrWorldScales) == std::size(g_arrCountryScales));
+
+inline std::string GetTagForIndex(std::string const & prefix, size_t ind)
+{
+  ASSERT(ind < std::size(g_arrWorldScales) && ind < std::size(g_arrCountryScales), (ind));
+  return prefix + char('0' + ind);
+}
+
+uint8_t PopulationToRank(uint64_t p);
+uint64_t RankToPopulation(uint8_t r);
+} // namespace feature