Use nested namespace

It's a mechanical change to modernize the code base

src/engine/guidance/assemble_overview.cpp

@@ -9,11 +9,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 namespace
 {
@@ -90,6 +86,4 @@ std::vector<util::Coordinate> assembleOverview(const std::vector<LegGeometry> &l
     return overview_geometry;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm

src/engine/guidance/assemble_route.cpp

@@ -2,11 +2,7 @@
 
 #include <numeric>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 Route assembleRoute(const std::vector<RouteLeg> &route_legs)
@@ -27,6 +23,4 @@ Route assembleRoute(const std::vector<RouteLeg> &route_legs)
     return Route{distance, duration, weight};
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm

src/engine/guidance/assemble_steps.cpp

@@ -8,13 +8,7 @@
 #include <cmath>
 #include <cstddef>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
-{
-namespace detail
+namespace osrm::engine::guidance::detail
 {
 
 std::pair<short, short> getDepartBearings(const LegGeometry &leg_geometry,
@@ -50,7 +44,4 @@ std::pair<short, short> getArriveBearings(const LegGeometry &leg_geometry,
     return std::make_pair<short, short>(
         std::round(util::coordinate_calculation::bearing(pre_turn_coordinate, turn_coordinate)), 0);
 }
-} // namespace detail
-} // namespace guidance
-} // namespace engine
 } // namespace osrm

src/engine/guidance/collapse_scenario_detection.cpp

@@ -6,11 +6,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -419,6 +415,4 @@ bool straightTurnFollowedByChoiceless(const RouteStepIterator step_entering_inte
            noIntermediaryIntersections(*step_entering_intersection);
 }
 
-} /* namespace guidance */
-} /* namespace engine */
 } /* namespace osrm */

src/engine/guidance/collapse_turns.cpp

@@ -10,11 +10,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using osrm::util::angularDeviation;
 using namespace osrm::guidance;
@@ -667,6 +663,4 @@ RouteSteps collapseSegregatedTurnInstructions(RouteSteps steps)
     return steps;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm

src/engine/guidance/lane_processing.cpp

@@ -9,11 +9,7 @@
 #include <unordered_set>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -209,6 +205,4 @@ std::vector<RouteStep> anticipateLaneChange(std::vector<RouteStep> steps,
     return steps;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm

src/engine/guidance/post_processing.cpp

@@ -21,11 +21,7 @@
 #include <limits>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -718,6 +714,4 @@ void applyOverrides(const datafacade::BaseDataFacade &facade,
     }
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm

src/engine/guidance/verbosity_reduction.cpp

@@ -4,11 +4,7 @@
 #include <boost/assert.hpp>
 #include <iterator>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -85,6 +81,4 @@ std::vector<RouteStep> suppressShortNameSegments(std::vector<RouteStep> steps)
     return removeNoTurnInstructions(std::move(steps));
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm