Correct setting attributes on lazily loaded instances

src/ifcparse/IfcParse.cpp

@@ -1008,6 +1008,10 @@ Argument* IfcEntityInstanceData::getArgument(unsigned int i) const {
 }
 
 void IfcEntityInstanceData::setArgument(unsigned int i, Argument* a, IfcUtil::ArgumentType attr_type) {
+	if (!initialized_) {
+		load_();
+	}
+
 	while (attributes_.size() < i) {
 		attributes_.push_back(new NullArgument());
 	}

src/ifcparse/IfcSpfHeader.cpp

@@ -41,6 +41,8 @@ HeaderEntity::HeaderEntity(const char * const datatype, IfcFile* file)
 	if (file) {
 		offset_in_file_ = file->stream->Tell();
 		load_();
+	} else {
+		initialized_ = true;
 	}
 }