From 23afb8fbd89453b1b18c597744fd8f1e3edb7c7f Mon Sep 17 00:00:00 2001
From: Osyotr <Osyotr@users.noreply.github.com>
Date: Fri, 13 Sep 2024 02:18:59 +0300
Subject: [PATCH 1/2] Don't recreate stream and locale in loop

Using `std::locale::classic()` instead of creating a new `std::locale` object on each iteration of the loop gives a massive performance boost.
Moving `std::stringstream` out of the loop further improves performance.
---
 IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp b/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp
index dca2d8472..ab33db9af 100644
--- a/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp
+++ b/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp
@@ -39,7 +39,7 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OU
 void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<BuildingModel> model)
 {
 	//imbue C locale to always use dots as decimal separator
-	stream.imbue(std::locale("C"));
+	stream.imbue(std::locale::classic());
 
 	const std::string& file_header_str = model->getFileHeader();
 	if(file_header_str.size() == 0)
@@ -70,6 +70,8 @@ void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<Buildi
 	auto t_start = std::chrono::high_resolution_clock::now();
 	std::atomic<int> counter = 0;
 	size_t numEntities = entityDataStrings.size();
+	std::stringstream tmpStream;
+	tmpStream.imbue(std::locale::classic());
 	FOR_EACH_LOOP entityDataStrings.begin(), entityDataStrings.end(), [&, this](std::tuple<int, shared_ptr<BuildingEntity>, std::string>& entityDataForOutput) {
 		shared_ptr<BuildingEntity> obj = std::get<1>(entityDataForOutput);
 		if (obj.use_count() < 2)
@@ -80,8 +82,6 @@ void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<Buildi
 				return;
 			}
 		}
-		std::stringstream tmpStream;
-		tmpStream.imbue(std::locale("C"));
 #ifdef EXTERNAL_WRITE_METHODS
 		getStepLine(obj, tmpStream);
 #else
@@ -89,6 +89,7 @@ void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<Buildi
 #endif
 		tmpStream << std::endl;
 		std::get<2>(entityDataForOutput) = tmpStream.str();
+		tmpStream.str(std::string());
 
 		counter.fetch_add(1);
 		int currentCount = counter.load();

From 89ac57a74ed617ae76c629948bcf4c5c291ac5f8 Mon Sep 17 00:00:00 2001
From: Osyotr <Osyotr@users.noreply.github.com>
Date: Fri, 13 Sep 2024 13:45:10 +0300
Subject: [PATCH 2/2] Don't move stream out of the loop

To prevent race condition
---
 IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp b/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp
index ab33db9af..cc6136b3f 100644
--- a/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp
+++ b/IfcPlusPlus/src/ifcpp/writer/WriterSTEP.cpp
@@ -70,8 +70,6 @@ void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<Buildi
 	auto t_start = std::chrono::high_resolution_clock::now();
 	std::atomic<int> counter = 0;
 	size_t numEntities = entityDataStrings.size();
-	std::stringstream tmpStream;
-	tmpStream.imbue(std::locale::classic());
 	FOR_EACH_LOOP entityDataStrings.begin(), entityDataStrings.end(), [&, this](std::tuple<int, shared_ptr<BuildingEntity>, std::string>& entityDataForOutput) {
 		shared_ptr<BuildingEntity> obj = std::get<1>(entityDataForOutput);
 		if (obj.use_count() < 2)
@@ -82,6 +80,8 @@ void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<Buildi
 				return;
 			}
 		}
+		std::stringstream tmpStream;
+		tmpStream.imbue(std::locale::classic());
 #ifdef EXTERNAL_WRITE_METHODS
 		getStepLine(obj, tmpStream);
 #else
@@ -89,7 +89,6 @@ void WriterSTEP::writeModelToStream(std::stringstream& stream, shared_ptr<Buildi
 #endif
 		tmpStream << std::endl;
 		std::get<2>(entityDataForOutput) = tmpStream.str();
-		tmpStream.str(std::string());
 
 		counter.fetch_add(1);
 		int currentCount = counter.load();