public static NPatch Diff(NElement oldE, ref NElement newE)
{
var oldSet = oldE != null;
var newSet = newE != null;
if (oldSet == newSet)
{
if (!oldSet)
{
return(null);
}
if (NPatch.ElementEquals(oldE, newE))
{
var oldC = oldE as NClass;
if (oldC != null)
{
var newC = (NClass)newE;
newE = oldE;
return(oldC.Upgrade(newC));
}
return(new NPropDiffer(oldE, newE).Diff());
}
}
return(NPatch.AssignNewValue);
}
NPatch Diff()
{
var cOld = _source.Length;
var cNew = _target.Length;
if (cOld == 0 || cNew == 0)
{
return(NPatch.AssignNewValue);
}
var iOld = 0;
var iNew = 0;
var iFix = 0;
for (;;)
{
var oldH = iOld < cOld;
var oldE = oldH ? _source[iOld] : null;
var newH = iNew < cNew;
var newE = newH ? _target[iNew] : null;
if (oldH)
{
if (newH && NPatch.ElementEquals(oldE, newE))
{
Update(iOld + iFix, newE, oldE);
iNew++;
}
else
{
Remove(iOld + iFix, oldE);
iFix--;
}
iOld++;
}
else
{
if (newH)
{
Insert(iOld + iFix, newE);
iOld++;
iNew++;
}
else
{
break;
}
}
}
Optimize();
TransferClasses();
return(_head != null ? new NListPatch(_head) : null);
}
void OptimizeRemove(NListPatchEntry e)
{
var delta = 0;
var oldE = e.Finalizer;
var last = e;
for (var i = e.Next; i != null; i = i.Next)
{
switch (i.Op)
{
case NListPatchOp.Insert:
{
var newE = i.Value;
if (NPatch.ElementEquals(newE, oldE))
{
e.Op = NListPatchOp.Move; // transform to move
e.Finalizer = null; // remove finalizer
e.iInsert = i.iInsert + delta; // correct insert index at the time of move
e.iFinal = i.iFinal; // preserve final index
e.Patch = NPropDiffer.Diff(oldE, ref newE); // make patch
e.Value = oldE; // preserve moved value
last.Next = i.Next; // delete insertion
return;
}
delta--;
}
break;
case NListPatchOp.Remove:
delta++;
break;
}
last = i;
}
}
