WIP: Export TimeTable to GTFS

CMakeLists.txt

@@ -17,6 +17,7 @@ include(cmake/pkg.cmake)
 add_custom_command(
       OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/generated/gtfsrt/gtfs-realtime.pb.h
       OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/generated/gtfsrt/gtfs-realtime.pb.cc
+      COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/generated/gtfsrt
       COMMAND ${CMAKE_CROSSCOMPILING_EMULATOR} $<TARGET_FILE:protoc>
       --cpp_out=${CMAKE_CURRENT_BINARY_DIR}/generated/gtfsrt
       --proto_path=${CMAKE_CURRENT_SOURCE_DIR}
@@ -116,6 +117,12 @@ add_executable(nigiri-import ${nigiri-import-files})
 target_link_libraries(nigiri-import PRIVATE nigiri boost-program_options ianatzdb-res)
 target_compile_features(nigiri-import PUBLIC cxx_std_23)
 
+# --- EXPORTER ---
+file(GLOB_RECURSE nigiri-export-files exe/export.cc)
+add_executable(nigiri-export ${nigiri-export-files})
+target_link_libraries(nigiri-export PRIVATE nigiri boost-program_options ianatzdb-res)
+target_compile_features(nigiri-export PUBLIC cxx_std_23)
+
 # --- BENCHMARK ---
 file(GLOB_RECURSE nigiri-benchmark-files exe/benchmark.cc)
 add_executable(nigiri-benchmark ${nigiri-benchmark-files})
@@ -148,4 +155,4 @@ if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
   target_link_options(nigiri-import PRIVATE -Wl,-no_deduplicate)
   target_link_options(nigiri-test PRIVATE -Wl,-no_deduplicate)
   target_link_options(nigiri-benchmark PRIVATE -Wl,-no_deduplicate)
-endif()
+endif()

exe/export.cc

@@ -0,0 +1,44 @@
+#include <filesystem>
+#include <iostream>
+
+#include "boost/program_options.hpp"
+
+#include "nigiri/export_gtfs.h"
+#include "nigiri/logging.h"
+#include "nigiri/timetable.h"
+#include "nigiri/types.h"
+
+using namespace nigiri;
+
+int main(int argc, char* argv[]) {
+  namespace bpo = boost::program_options;
+
+  auto tt_path = std::filesystem::path{};
+  auto gtfs_dir = std::filesystem::path{};
+
+  bpo::options_description desc("Allowed options");
+  desc.add_options()("help,h", "produce this help message")  //
+      ("tt_path,p", bpo::value(&tt_path)->required(),
+       "path to a binary file containing a serialized nigiri timetable")  //
+      ("gtfs_export_dir,o", bpo::value(&gtfs_dir)->required(),
+       "path to the directory to export the timetable as GTFS");
+  bpo::variables_map vm;
+  bpo::store(bpo::command_line_parser(argc, argv).options(desc).run(), vm);
+
+  if (vm.count("help") != 0U) {
+    std::cout << desc << "\n";
+    return 0;
+  }
+
+  bpo::notify(vm);
+
+  std::cout << "loading timetable...\n";
+  auto tt = *nigiri::timetable::read(tt_path);
+  tt.resolve();
+
+  std::cout << "exporting timetable as GTFS...\n";
+  export_gtfs(tt, gtfs_dir);
+  std::cout << "done.\n";
+
+  return 0;
+}

include/nigiri/export_gtfs.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <filesystem>
+
+#include "nigiri/timetable.h"
+
+namespace nigiri {
+
+struct timetable;
+
+// Skip the first 9 stops, bcs they are sentinels
+constexpr int stopOffset{9};
+
+void export_gtfs(timetable const& tt, std::filesystem::path const& output_dir);
+
+void write_feed_info(std::filesystem::path const& output_dir);
+
+void write_agencies(timetable const& tt,
+                    std::filesystem::path const& output_dir);
+
+void write_stops(timetable const& tt, std::filesystem::path const& output_dir);
+
+void write_stop_times(timetable const& tt,
+                      std::filesystem::path const& output_dir);
+
+void write_trips(timetable const& tt,
+                 std::filesystem::path const& output_dir,
+                 std::vector<size_t> const& route_offsets);
+
+void write_routes(timetable const& tt,
+                  std::filesystem::path const& output_dir,
+                  std::vector<size_t> const& route_offsets);
+
+void write_calendar(timetable const& tt,
+                    std::filesystem::path const& output_dir);
+
+void write_calendar_dates(timetable const& tt,
+                          std::filesystem::path const& output_dir);
+
+void write_transfers(timetable const& tt,
+                     std::filesystem::path const& output_dir);
+
+}  // namespace nigiri