New cpp folder structure

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

libs/routing/cross_border_graph.cpp

@@ -0,0 +1,59 @@
+#include "routing/cross_border_graph.hpp"
+
+#include "geometry/mercator.hpp"
+
+namespace routing
+{
+void CrossBorderGraph::AddCrossBorderSegment(RegionSegmentId segId,
+                                             CrossBorderSegment const & segment)
+{
+  m_segments.emplace(segId, segment);
+
+  auto addEndingToMwms = [&](CrossBorderSegmentEnding const & ending)
+  {
+    auto [it, inserted] = m_mwms.emplace(ending.m_numMwmId, std::vector<RegionSegmentId>{segId});
+    if (!inserted)
+      it->second.push_back(segId);
+  };
+
+  addEndingToMwms(segment.m_start);
+  addEndingToMwms(segment.m_end);
+}
+
+CrossBorderSegmentEnding::CrossBorderSegmentEnding(m2::PointD const & point, NumMwmId const & mwmId)
+  : m_point(mercator::ToLatLon(point), geometry::kDefaultAltitudeMeters), m_numMwmId(mwmId)
+{
+}
+
+CrossBorderSegmentEnding::CrossBorderSegmentEnding(ms::LatLon const & point, NumMwmId const & mwmId)
+  : m_point(point, 0), m_numMwmId(mwmId)
+{
+}
+
+CrossBorderGraphSerializer::Header::Header(CrossBorderGraph const & graph, uint32_t version)
+  : m_numRegions(static_cast<uint32_t>(graph.m_mwms.size()))
+  , m_numRoads(static_cast<uint32_t>(graph.m_segments.size()))
+  , m_version(version)
+{
+}
+
+// static
+uint32_t CrossBorderGraphSerializer::Hash(std::string const & s)
+{
+  // We use RSHash (Real Simple Hash) variation. RSHash is a standard hash calculating function
+  // described in Robert Sedgwick's "Algorithms in C". The difference between this implementation
+  // and the original algorithm is that we return hash, not (hash & & 0x7FFFFFFF).
+  uint32_t constexpr b = 378551;
+  uint32_t a = 63689;
+
+  uint32_t hash = 0;
+
+  for (auto c : s)
+  {
+    hash = hash * a + c;
+    a *= b;
+  }
+
+  return hash;
+}
+}  // namespace routing