New cpp folder structure

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

libs/drape_frontend/tile_utils.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+#include "drape_frontend/tile_key.hpp"
+
+#include <functional>
+#include <set>
+
+namespace df
+{
+using TTilesCollection = std::set<TileKey>;
+
+struct CoverageResult
+{
+  int m_minTileX = 0;
+  int m_maxTileX = 0;
+  int m_minTileY = 0;
+  int m_maxTileY = 0;
+};
+
+// This function determines the tiles coverage in specified zoom level.
+// Each tile can be processed in processTile callback.
+CoverageResult CalcTilesCoverage(m2::RectD const & rect, int targetZoom,
+                                 std::function<void(int, int)> const & processTile);
+
+// This function checks if tileKey1 and tileKey2 are neighbours
+bool IsNeighbours(TileKey const & tileKey1, TileKey const & tileKey2);
+
+// This function performs clipping by maximum zoom label available for map data.
+int ClipTileZoomByMaxDataZoom(int zoom);
+
+// This function returns tile key by point on specific zoom level.
+TileKey GetTileKeyByPoint(m2::PointD const & pt, int zoom);
+}  // namespace df