private static RdTextChange CreateTextChange(int offset, [CanBeNull] InsertText insert, [CanBeNull] DeleteText delete,
int documentLength)
{
var newText = insert?.Text ?? "";
var oldText = delete?.Text ?? "";
var startOffset = offset - (insert?.GetTextLengthAfter() ?? 0);
RdTextChangeKind kind;
if (insert != null && delete != null)
{
kind = RdTextChangeKind.Replace;
}
else if (insert != null)
{
kind = RdTextChangeKind.Insert;
}
else if (delete != null)
{
kind = RdTextChangeKind.Remove;
}
else
{
throw new ArgumentOutOfRangeException();
}
return(new RdTextChange(kind, startOffset, oldText, newText, documentLength));
}
private static IEnumerable <OtChange> Normalize(IEnumerable <OtChange> changes)
{
var result = new List <OtChange>();
OtChange prev = null;
foreach (var curr in changes)
{
if (curr.IsId())
{
continue;
}
if (prev is Retain && curr is Retain)
{
prev = new Retain(((Retain)prev).Offset + ((Retain)curr).Offset);
}
else if (prev is InsertText && curr is InsertText)
{
prev = new InsertText(((InsertText)prev).Text + ((InsertText)curr).Text);
}
else if (prev is DeleteText && curr is DeleteText)
{
prev = new DeleteText(((DeleteText)prev).Text + ((DeleteText)curr).Text);
}
else
{
if (prev != null)
{
result.Add(prev);
}
prev = curr;
}
}
if (prev != null)
{
result.Add(prev);
}
if (result.Count == 0)
{
result.Add(new Retain(0));
}
return(result);
}
public static List <RdTextChange> ToRdTextChanges(this OtOperation op)
{
var documentLength = op.DocumentLengthBefore();
var currOffset = 0;
InsertText lastInsert = null;
DeleteText lastDelete = null;
var res = new List <RdTextChange>();
foreach (var change in op.Changes)
{
switch (change)
{
case Retain _:
{
if (lastDelete != null || lastInsert != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
lastDelete = null;
lastInsert = null;
}
break;
}
case InsertText i:
{
if (lastInsert != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
lastDelete = null;
}
documentLength += change.GetTextLengthAfter();
lastInsert = i;
break;
}
case DeleteText d:
{
if (lastDelete != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
lastInsert = null;
}
documentLength -= change.GetTextLengthBefore();
lastDelete = d;
break;
}
}
currOffset += change.GetTextLengthAfter();
}
if (lastDelete != null || lastInsert != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
}
return(res);
}
