public Delta Diff(Delta other)
{
if (this == other)
{
return(new Delta());
}
if (!TryConcatInserts(this, out string thisStr) || !TryConcatInserts(other, out string otherStr))
{
throw new InvalidOperationException("Both deltas must be documents.");
}
var delta = new Delta();
List <Diff> diffResult = Differ.Compute(thisStr, otherStr);
var thisIter = new OpIterator(this.Ops);
var otherIter = new OpIterator(other.Ops);
foreach (Diff component in diffResult)
{
int length = component.Text.Length;
while (length > 0)
{
int opLength = 0;
switch (component.Operation)
{
case Operation.Insert:
opLength = Math.Min(otherIter.PeekLength(), length);
delta.Add(otherIter.Next(opLength));
break;
case Operation.Delete:
opLength = Math.Min(length, thisIter.PeekLength());
thisIter.Next(opLength);
delta.Delete(opLength);
break;
case Operation.Equal:
opLength = Math.Min(Math.Min(thisIter.PeekLength(), otherIter.PeekLength()), length);
JToken thisOp = thisIter.Next(opLength);
JToken otherOp = otherIter.Next(opLength);
if (JToken.DeepEquals(thisOp[InsertType], otherOp[InsertType]))
{
delta.Retain(opLength, DiffAttributes(thisOp[Attributes], otherOp[Attributes]));
}
else
{
delta.Add(otherOp);
delta.Delete(opLength);
}
break;
}
length -= opLength;
}
}
return(delta.Chop());
}
public Delta Compose(Delta other)
{
var thisIter = new OpIterator(_ops);
var otherIter = new OpIterator(other._ops);
var delta = new Delta();
while (thisIter.HasNext() || otherIter.HasNext())
{
if (otherIter.PeekType() == InsertType)
{
delta.Add(otherIter.Next());
}
else if (thisIter.PeekType() == DeleteType)
{
delta.Add(thisIter.Next());
}
else
{
int length = Math.Min(thisIter.PeekLength(), otherIter.PeekLength());
JToken thisOp = thisIter.Next(length);
JToken otherOp = otherIter.Next(length);
if (otherOp.OpType() == RetainType)
{
var newOp = new JObject();
if (thisOp.OpType() == RetainType)
{
newOp[RetainType] = length;
}
else
{
newOp[InsertType] = thisOp[InsertType];
}
JToken attributes = ComposeAttributes(thisOp[Attributes], otherOp[Attributes],
thisOp.OpType() == RetainType);
if (attributes != null)
{
newOp[Attributes] = attributes;
}
delta.Add(newOp);
}
else if (otherOp.OpType() == DeleteType && thisOp.OpType() == RetainType)
{
delta.Add(otherOp);
}
}
}
return(delta.Chop());
}