Fix reading mmCIF file where model is defined but model 1 is missing. Version bump.

CMakeLists.txt

@@ -25,7 +25,7 @@
 cmake_minimum_required(VERSION 3.16)
 
 # set the project name
-project(cifpp VERSION 2.0.2 LANGUAGES CXX)
+project(cifpp VERSION 2.0.3 LANGUAGES CXX)
 
 list(PREPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 

changelog

+Version 2.0.3
+- Fixed reading mmCIF files where model numbers are used and
+  model number 1 is missing.
+
 Version 2.0.2
 - Added configuration flag to disable downloading CCD data during build
   Note that there are now two flags for CCD data:

include/cif++/Structure.hpp

@@ -533,6 +533,8 @@ class Structure
 	void loadData();
 	void updateAtomIndex();
 
+	void loadAtomsForModel(StructureOpenOptions options);
+
 	File &mFile;
 	size_t mModelNr;
 	AtomView mAtoms;

src/Structure.cpp

@@ -1790,6 +1790,33 @@ Structure::Structure(File &f, size_t modelNr, StructureOpenOptions options)
 
 	auto &atomCat = (*db)["atom_site"];
 
+	loadAtomsForModel(options);
+
+	// Check to see if we should actually load another model?
+	if (mAtoms.empty() and mModelNr == 1)
+	{
+		std::optional<size_t> model_nr;
+		cif::tie(model_nr) = atomCat.front().get("pdbx_PDB_model_num");
+		if (model_nr and *model_nr != mModelNr)
+		{
+			if (cif::VERBOSE)
+				std::cerr << "No atoms loaded for model 1, trying model " << *model_nr << std::endl;
+			mModelNr = *model_nr;
+			loadAtomsForModel(options);
+		}
+	}
+
+	if (mAtoms.empty())
+		throw std::runtime_error("No atoms loaded, refuse to continue");
+
+	loadData();
+}
+
+void Structure::loadAtomsForModel(StructureOpenOptions options)
+{
+	auto db = mFile.impl().mDb;
+	auto &atomCat = (*db)["atom_site"];
+
 	for (auto &a : atomCat)
 	{
 		std::string id, type_symbol;
@@ -1805,10 +1832,9 @@ Structure::Structure(File &f, size_t modelNr, StructureOpenOptions options)
 
 		mAtoms.emplace_back(new AtomImpl(*db, id, a));
 	}
-
-	loadData();
 }
 
+
 Structure::Structure(const Structure &s)
 	: mFile(s.mFile)
 	, mModelNr(s.mModelNr)