void DetectAndSaveChange(string new_text, int new_sel_start, int new_sel_length)
{
if (m_PrevText != null)
{
// We are doing brutalforce change detection as we will work with at most a few hundred kilobytes of text in this project.
int max_len = Math.Min(m_PrevText.Length, new_text.Length);
// The Math.Min(m_PrevSelStart, max_len) is there to fix a bug that detected wrongly the actual location of
// multiple pasted lines. If we pasted lines that are equivalent to the lines starting at the actual paste
// location then this change detector found our newly pasted text as unchanged text and detected the next
// block as the change. This caused problems especially in case of the optimized syntax highlighter.
int common_prefix_len = FindCommonPrefixLength(m_PrevText, new_text, Math.Min(m_PrevSelStart, max_len));
if (m_PrevText.Length == new_text.Length && new_text.Length == common_prefix_len)
{
return;
}
int common_postfix_len = common_prefix_len >= max_len ? 0 : FindCommonPostfixLen(m_PrevText, new_text, max_len - common_prefix_len);
UndoEntry entry = new UndoEntry();
entry.Id = m_NextUndoEntryId++;
entry.PrevCaretPos = m_PrevSelStart + m_PrevSelLength;
entry.NewCaretPos = new_sel_start + new_sel_length;
entry.Pos = common_prefix_len;
entry.CutText = m_PrevText.Substring(common_prefix_len, m_PrevText.Length - common_prefix_len - common_postfix_len);
entry.PastedText = new_text.Substring(common_prefix_len, new_text.Length - common_prefix_len - common_postfix_len);
m_UndoBuffer.AddChange(entry);
if (UndoEntryAdded != null)
{
UndoEntryAdded(entry);
}
}
m_PrevText = new_text;
m_PrevSelStart = new_sel_start;
m_PrevSelLength = new_sel_length;
}
