Allow missing CRYST1 record in PDB files... finally

src/pdb/pdb2cif.cpp

@@ -5277,6 +5277,8 @@ void PDBFileParser::ParseMiscellaneousFeatures()
 
 void PDBFileParser::ParseCrystallographic()
 {
+	if (mRec->is("CRYST1"))
+	{
 		Match("CRYST1", true);
 
 		getCategory("cell")->emplace({
@@ -5307,6 +5309,29 @@ void PDBFileParser::ParseCrystallographic()
 			{ "Int_Tables_number", intTablesNr } });
 
 		GetNextRecord();
+	}
+	else
+	{
+		// no cryst1, make a simple one, like this:
+		// CRYST1    1.000    1.000    1.000  90.00  90.00  90.00 P 1           1
+		getCategory("cell")->emplace({
+			{ "entry_id", mStructureID }, //	 1 -  6       Record name   "CRYST1"
+			{ "length_a", 1 },            //	 7 - 15       Real(9.3)     a              a (Angstroms).
+			{ "length_b", 1 },            //	16 - 24       Real(9.3)     b              b (Angstroms).
+			{ "length_c", 1 },            //	25 - 33       Real(9.3)     c              c (Angstroms).
+			{ "angle_alpha", 90 },        //	34 - 40       Real(7.2)     alpha          alpha (degrees).
+			{ "angle_beta", 90 },         //	41 - 47       Real(7.2)     beta           beta (degrees).
+			{ "angle_gamma", 90 },        //	48 - 54       Real(7.2)     gamma          gamma (degrees).
+			/* goes into symmetry */      //	56 - 66       LString       sGroup         Space  group.
+			{ "Z_PDB", 1 }                //	67 - 70       Integer       z              Z value.
+		});
+
+		getCategory("symmetry")->emplace({
+			{ "entry_id", mStructureID },
+			{ "space_group_name_H-M", "P 1" },
+			{ "Int_Tables_number", 1 }
+		});
+	}
 }
 
 void PDBFileParser::ParseCoordinateTransformation()