internal List<UnchangedSegment> GetReuseMapTo(ITextSourceVersion newVersion)
{
ITextSourceVersion oldVersion = this.Version;
if (oldVersion == null || newVersion == null)
return null;
if (!oldVersion.BelongsToSameDocumentAs(newVersion))
return null;
List<UnchangedSegment> reuseMap = new List<UnchangedSegment>();
reuseMap.Add(new UnchangedSegment(0, 0, this.TextLength));
foreach (var change in oldVersion.GetChangesTo(newVersion)) {
bool needsSegmentRemoval = false;
for (int i = 0; i < reuseMap.Count; i++) {
UnchangedSegment segment = reuseMap[i];
if (segment.NewOffset + segment.Length <= change.Offset) {
// change is completely after this segment
continue;
}
if (change.Offset + change.RemovalLength <= segment.NewOffset) {
// change is completely before this segment
segment.NewOffset += change.InsertionLength - change.RemovalLength;
reuseMap[i] = segment;
continue;
}
// Change is overlapping segment.
// Split segment into two parts: the part before change, and the part after change.
var segmentBefore = new UnchangedSegment(segment.OldOffset, segment.NewOffset, change.Offset - segment.NewOffset);
Debug.Assert(segmentBefore.Length < segment.Length);
int lengthAtEnd = segment.NewOffset + segment.Length - (change.Offset + change.RemovalLength);
var segmentAfter = new UnchangedSegment(
segment.OldOffset + segment.Length - lengthAtEnd,
change.Offset + change.InsertionLength,
lengthAtEnd);
Debug.Assert(segmentAfter.Length < segment.Length);
Debug.Assert(segmentBefore.Length + segmentAfter.Length <= segment.Length);
Debug.Assert(segmentBefore.NewOffset + segmentBefore.Length <= segmentAfter.NewOffset);
Debug.Assert(segmentBefore.OldOffset + segmentBefore.Length <= segmentAfter.OldOffset);
if (segmentBefore.Length > 0 && segmentAfter.Length > 0) {
reuseMap[i] = segmentBefore;
reuseMap.Insert(++i, segmentAfter);
} else if (segmentBefore.Length > 0) {
reuseMap[i] = segmentBefore;
} else {
reuseMap[i] = segmentAfter;
if (segmentAfter.Length <= 0)
needsSegmentRemoval = true;
}
}
if (needsSegmentRemoval)
reuseMap.RemoveAll(s => s.Length <= 0);
}
return reuseMap;
}
internal List <UnchangedSegment> GetReuseMapTo(ITextSourceVersion newVersion)
{
ITextSourceVersion oldVersion = this.Version;
if (oldVersion == null || newVersion == null)
{
return(null);
}
if (!oldVersion.BelongsToSameDocumentAs(newVersion))
{
return(null);
}
List <UnchangedSegment> reuseMap = new List <UnchangedSegment>();
reuseMap.Add(new UnchangedSegment(0, 0, this.TextLength));
foreach (var change in oldVersion.GetChangesTo(newVersion))
{
bool needsSegmentRemoval = false;
for (int i = 0; i < reuseMap.Count; i++)
{
UnchangedSegment segment = reuseMap[i];
if (segment.NewOffset + segment.Length <= change.Offset)
{
// change is completely after this segment
continue;
}
if (change.Offset + change.RemovalLength <= segment.NewOffset)
{
// change is completely before this segment
segment.NewOffset += change.InsertionLength - change.RemovalLength;
reuseMap[i] = segment;
continue;
}
// Change is overlapping segment.
// Split segment into two parts: the part before change, and the part after change.
var segmentBefore = new UnchangedSegment(segment.OldOffset, segment.NewOffset, change.Offset - segment.NewOffset);
Debug.Assert(segmentBefore.Length < segment.Length);
int lengthAtEnd = segment.NewOffset + segment.Length - (change.Offset + change.RemovalLength);
var segmentAfter = new UnchangedSegment(
segment.OldOffset + segment.Length - lengthAtEnd,
change.Offset + change.InsertionLength,
lengthAtEnd);
Debug.Assert(segmentAfter.Length < segment.Length);
Debug.Assert(segmentBefore.Length + segmentAfter.Length <= segment.Length);
Debug.Assert(segmentBefore.NewOffset + segmentBefore.Length <= segmentAfter.NewOffset);
Debug.Assert(segmentBefore.OldOffset + segmentBefore.Length <= segmentAfter.OldOffset);
if (segmentBefore.Length > 0 && segmentAfter.Length > 0)
{
reuseMap[i] = segmentBefore;
reuseMap.Insert(++i, segmentAfter);
}
else if (segmentBefore.Length > 0)
{
reuseMap[i] = segmentBefore;
}
else
{
reuseMap[i] = segmentAfter;
if (segmentAfter.Length <= 0)
{
needsSegmentRemoval = true;
}
}
}
if (needsSegmentRemoval)
{
reuseMap.RemoveAll(s => s.Length <= 0);
}
}
return(reuseMap);
}