Revert "[FEATURE] cherry-pick json parsing changes"

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "external/madrona"]
 	path = external/madrona
 	url = https://github.com/shacklettbp/madrona.git
+[submodule "external/json"]
+	path = external/json
+	url = https://github.com/nlohmann/json.git

src/CMakeLists.txt

@@ -33,7 +33,7 @@ target_link_libraries(gpudrive_mgr
     PUBLIC
         madrona_python_utils
     PRIVATE
-        madrona_json
+        nlohmann_json::nlohmann_json
         gpudrive_cpu_impl
         madrona_mw_cpu
         madrona_common

src/MapReader.cpp

@@ -36,13 +36,8 @@ madrona_gpudrive::Map *copyToArrayOnHostOrDevice(const madrona_gpudrive::Map *in
 
 namespace madrona_gpudrive {
 
-simdjson::dom::parser& MapReader::getParser() {
-  static simdjson::dom::parser parser;
-  return parser;
-}
-
-MapReader::MapReader(const std::string &pathToFile){
-  in_ = pathToFile;
+MapReader::MapReader(const std::string &pathToFile) : in_(pathToFile) {
+  assert(in_.is_open());
   map_ = new madrona_gpudrive::Map();
 }
 
@@ -51,13 +46,10 @@ MapReader::~MapReader() {
 }
 
 void MapReader::doParse(float polylineReductionThreshold) {
-    // Parse with simdjson
-    auto& parser = getParser();
-    simdjson::dom::element doc;
-    auto error = parser.load(in_).get(doc);
+  nlohmann::json rawJson;
+  in_ >> rawJson;
 
-    // Parse the document into the map
-    from_json(doc, *map_, polylineReductionThreshold);
+  from_json(rawJson, *map_, polylineReductionThreshold);
 }
 
 madrona_gpudrive::Map* MapReader::parseAndWriteOut(const std::string &path,
@@ -68,4 +60,4 @@ madrona_gpudrive::Map* MapReader::parseAndWriteOut(const std::string &path,
   return copyToArrayOnHostOrDevice(reader.map_, executionMode);
 
 } 
-} // namespace madrona_gpudrive
+} // namespace madrona_gpudrive

src/MapReader.hpp

@@ -2,7 +2,7 @@
 
 #include <fstream>
 #include <madrona/exec_mode.hpp>
-#include <simdjson.h>
+
 #include "init.hpp"
 
 namespace madrona_gpudrive {
@@ -14,13 +14,12 @@ class MapReader {
   static madrona_gpudrive::Map* parseAndWriteOut(const std::string &path, madrona::ExecMode executionMode, float polylineReductionThreshold);
 
 private:
-  static simdjson::dom::parser& getParser();
   MapReader(const std::string &pathToFile);
   ~MapReader();
   void doParse(float polylineReductionThreshold);
 
-  std::string in_;
+  std::ifstream in_;
   madrona_gpudrive::Map *map_;
 };
 
-} // namespace madrona_gpudrive
+} // namespace madrona_gpudrive