private static bool MoleculeMatchesRecursive(AtomDefinition atomDefinition1, AtomDefinition atomDefinition2, List <AtomDefinition> undoStack)
{
// Make sure we don't match an atom that's already matched with something else. This check also prevents infinite
// recursion when an atom is revisited by one of its neighbors.
if (atomDefinition1.proposedCounterpart != null || atomDefinition2.proposedCounterpart != null)
{
return(atomDefinition1.proposedCounterpart == atomDefinition2 && atomDefinition2.proposedCounterpart == atomDefinition1);
}
if (atomDefinition1.atom == atomDefinition2.atom && IdenticalBonds(atomDefinition1, atomDefinition2))
{
int undoStackTop = undoStack.Count;
// undoStack contains all atoms that have a proposed counterpart. It's used to clean up counterparts if a full match cannot be made.
// Indexes smaller than undoStackTop represent assumptions made by callers in higher levels. At this level, we treat them as
// absolute fact. Indexes larger or equal to undoStackTop represent assumptions made in this call, or lower callers. We must undo
// these assumptions if we can't make a full match.
atomDefinition1.proposedCounterpart = atomDefinition2;
atomDefinition2.proposedCounterpart = atomDefinition1;
undoStack.Add(atomDefinition1);
undoStack.Add(atomDefinition2);
bool flag1 = true;
foreach (BondDefinition bond in atomDefinition1.bonds)
{
AtomDefinition subAtom1 = (bond.atom1 == atomDefinition1 ? bond.atom2 : bond.atom1);
bool flag2 = false;
foreach (AtomDefinition subAtom2 in atomDefinition2.GetBondedAtoms(bond.bondCount))
{
if (MoleculeMatchesRecursive(subAtom1, subAtom2, undoStack))
{
flag2 = true;
break;
}
// It's an invariant that whenever MoleculeMatchesRecursive retuns false, it restores undoStack
// to the state it was on method entry, so no need to touch undoStack here.
}
if (!flag2) // Found no match for subAtomDefinition1, molecule mismatch
{
flag1 = false;
break; // Return false through the recursion
}
}
if (flag1)
{
return(true);
}
// clean up the assumptions
while (undoStack.Count > undoStackTop)
{
undoStack[undoStack.Count - 1].proposedCounterpart = null;
undoStack.RemoveAt(undoStack.Count - 1);
}
}
return(false);
}
public Atom(Molecule molecule, AtomDefinition definition)
{
this.Molecule = molecule;
this.MolecularPosition = definition.Position;
this.Element = definition.Element;
}
private static bool IdenticalBonds(AtomDefinition atom1, AtomDefinition atom2)
{
return(false);
}
