// Update after an insertion.
public static unsafe void InsertionUpdate
(TextTree tree, TextBuffer buffer,
int offset, int length)
{
// NOTE: this is here to keep the method calls down to
// a minimum... technically, this belongs in the
// tree, but it's more efficient to do this here,
// where we can access the line/node fields
// directly
// declare the start offset of the insertion line
int lineStart;
// find the insertion line
TextLine line = tree.FindLineByCharOffset
(offset, out lineStart);
// get the parent of the insertion line
TextNode parent = line.Parent;
// get the end offset of the insertion line
int lineEnd = line.end.Offset;
// create a text slice
TextSlice slice = new TextSlice();
// get the inserted data into the slice
buffer.GetSlice(offset, length, slice);
// get the current line start position
int currStart = lineStart;
// get the current line end position
int currEnd = (offset + 1);
// set the default new line list
TextLine first = null;
// set the default previous new line
TextLine prev = null;
// find and create new lines, quickly
fixed(char* start = &slice.chars[slice.start])
{
char* curr = start;
// get the insertion end position
char* end = (curr + slice.length);
// find and create new lines
while(curr != end)
{
if(*curr == '\n')
{
if(currStart == lineStart)
{
// shorten the insertion line
line.end.Move(currEnd);
}
else
{
// create a new line
TextLine newline = new TextLine
(buffer.MarkPosition(currStart, true),
buffer.MarkPosition(currEnd, true));
// update list links
if(first == null)
{
// set the current line as the first
first = newline;
}
else
{
// set the current line's prev
newline.prev = prev;
// set the previous line's next
prev.next = newline;
}
// set the previous line to the current
prev = newline;
}
// update the current line start position
currStart = currEnd;
}
// increment the current input pointer
++curr;
// increment the current line end position
++currEnd;
}
}
// insert new lines and rebalance parent, if needed
if(first != null)
{
// add any remaining characters to new line
if(currEnd < lineEnd)
{
// create a new line
TextLine newline = new TextLine
(buffer.MarkPosition(currStart, true),
buffer.MarkPosition(currEnd, true));
// set the current line's prev reference
newline.prev = prev;
// set the previous line's next reference
prev.next = newline;
}
// insert the new lines
parent.InsertChildren(line, first);
// rebalance, starting at the new lines' parent
parent.Rebalance(tree);
}
}