/** This method is called by Swing to delete text from this document. */
@Override
public void remove(int offset, int length) throws BadLocationException {
if (length == 0) return;
if (undone > 0) {
now = now - undone;
undone = 0;
} // clear the REDO entries
String string = toString().substring(offset, offset + length);
super.remove(offset, length);
if (now > 0 && !insert[now - 1]) { // merge with last edit if possible
if (where[now - 1] == offset) {
text[now - 1] += string;
return;
}
if (where[now - 1] == offset + length) {
where[now - 1] = offset;
text[now - 1] = string + text[now - 1];
return;
}
}
if (now >= MAXUNDO) {
arraycopy(insert, 1, insert, 0, MAXUNDO - 1);
arraycopy(text, 1, text, 0, MAXUNDO - 1);
arraycopy(where, 1, where, 0, MAXUNDO - 1);
now--;
}
insert[now] = false;
text[now] = string;
where[now] = offset;
now++;
}
/** This method is called by Swing to insert a String into this document. */
@Override
public void insertString(int offset, String string, AttributeSet attr)
throws BadLocationException {
if (string.length() == 0) return;
else if (string.indexOf('\r') >= 0)
string = Util.convertLineBreak(string); // we don't want '\r'
if (undone > 0) {
now = now - undone;
undone = 0;
} // clear the REDO entries
super.insertString(offset, string, attr);
if (now > 0 && insert[now - 1]) { // merge with last edit if possible
if (where[now - 1] == offset - text[now - 1].length()) {
text[now - 1] += string;
return;
}
}
if (now >= MAXUNDO) {
arraycopy(insert, 1, insert, 0, MAXUNDO - 1);
arraycopy(text, 1, text, 0, MAXUNDO - 1);
arraycopy(where, 1, where, 0, MAXUNDO - 1);
now--;
}
insert[now] = true;
text[now] = string;
where[now] = offset;
now++;
}
/**
* Perform undo then return where the new desired caret location should be (or return -1 if undo
* is not possible right now)
*/
public int do_undo() {
if (undone >= now) return -1;
else undone++;
boolean insert = this.insert[now - undone];
String text = this.text[now - undone];
int where = this.where[now - undone];
try {
if (insert) {
super.remove(where, text.length());
return where;
} else {
super.insertString(where, text, attr);
return where + text.length();
}
} catch (BadLocationException ex) {
return -1;
}
}