public string GetOldText(Span span)
{
if (span.End > this.OldLength)
{
throw new ArgumentOutOfRangeException(nameof(span));
}
return(_oldText.Substring(span));
}
private static IList <TextChange> GetChangesFromDifferenceCollection(ref int delta,
TextChange originalChange,
ChangeString oldText,
ChangeString newText,
IHierarchicalDifferenceCollection diffCollection,
int leftOffset = 0,
int rightOffset = 0)
{
List <TextChange> changes = new List <TextChange>();
for (int i = 0; i < diffCollection.Differences.Count; i++)
{
Difference currentDiff = diffCollection.Differences[i];
Span leftDiffSpan = Translate(diffCollection.LeftDecomposition.GetSpanInOriginal(currentDiff.Left), leftOffset);
Span rightDiffSpan = Translate(diffCollection.RightDecomposition.GetSpanInOriginal(currentDiff.Right), rightOffset);
// TODO: Since this evaluates differences lazily, we should add something here to *not* compute the next
// level of differences if we think it would be too expensive.
IHierarchicalDifferenceCollection nextLevelDiffs = diffCollection.GetContainedDifferences(i);
if (nextLevelDiffs != null)
{
changes.AddRange(GetChangesFromDifferenceCollection(ref delta, originalChange, oldText, newText, nextLevelDiffs, leftDiffSpan.Start, rightDiffSpan.Start));
}
else
{
TextChange minimalChange = new TextChange(originalChange.OldPosition + leftDiffSpan.Start,
oldText.Substring(leftDiffSpan),
newText.Substring(rightDiffSpan),
ComputeBoundaryConditions(originalChange, oldText, leftDiffSpan));
minimalChange.NewPosition = originalChange.NewPosition + rightDiffSpan.Start;
if (minimalChange.OldLength > 0 && minimalChange.NewLength > 0)
{
minimalChange.IsOpaque = true;
}
delta += minimalChange.Delta;
changes.Add(minimalChange);
}
}
return(changes);
}
