Move selection update code to SelectionList

1 files changed, 90 insertions, 0 deletions

diff --git a/src/selection.cc b/src/selection.cc
index 065aaefc..0e6bd710 100644
--- a/src/selection.cc
+++ b/src/selection.cc
@@ -52,4 +52,94 @@ void Selection::avoid_eol()
     Kakoune::avoid_eol(last());
 }
 
+namespace
+{
+
+template<template <bool, bool> class UpdateFunc>
+void on_buffer_change(SelectionList& sels, const BufferCoord& begin, const BufferCoord& end, LineCount end_line)
+{
+    auto update_beg = std::lower_bound(sels.begin(), sels.end(), begin,
+                                       [](const Selection& s, const BufferCoord& c) { return std::max(s.first(), s.last()).coord() < c; });
+    auto update_only_line_beg = std::upper_bound(sels.begin(), sels.end(), end_line,
+                                                 [](LineCount l, const Selection& s) { return l < std::min(s.first(), s.last()).line(); });
+
+    if (update_beg != update_only_line_beg)
+    {
+        // for the first one, we are not sure if min < begin
+        UpdateFunc<false, false>{}(update_beg->first(), begin, end);
+        UpdateFunc<false, false>{}(update_beg->last(), begin, end);
+    }
+    for (auto it = update_beg+1; it < update_only_line_beg; ++it)
+    {
+        UpdateFunc<false, true>{}(it->first(), begin, end);
+        UpdateFunc<false, true>{}(it->last(), begin, end);
+    }
+    if (end.line > begin.line)
+    {
+        for (auto it = update_only_line_beg; it != sels.end(); ++it)
+        {
+            UpdateFunc<true, true>{}(it->first(), begin, end);
+            UpdateFunc<true, true>{}(it->last(), begin, end);
+        }
+    }
+}
+
+template<bool assume_different_line, bool assume_greater_than_begin>
+struct UpdateInsert
+{
+    void operator()(BufferIterator& it,
+                    const BufferCoord& begin, const BufferCoord& end) const
+    {
+        BufferCoord coord = it.coord();
+        if (assume_different_line)
+            kak_assert(begin.line < coord.line);
+        if (not assume_greater_than_begin and coord < begin)
+            return;
+        if (not assume_different_line and begin.line == coord.line)
+            coord.column = end.column + coord.column - begin.column;
+
+        coord.line += end.line - begin.line;
+        it = coord;
+    }
+};
+
+template<bool assume_different_line, bool assume_greater_than_begin>
+struct UpdateErase
+{
+    void operator()(BufferIterator& it,
+                    const BufferCoord& begin, const BufferCoord& end) const
+    {
+        BufferCoord coord = it.coord();
+        if (not assume_greater_than_begin and coord < begin)
+            return;
+        if (assume_different_line)
+            kak_assert(end.line < coord.line);
+        if (not assume_different_line and coord <= end)
+            coord = it.buffer().clamp(begin);
+        else
+        {
+            if (not assume_different_line and end.line == coord.line)
+            {
+                coord.line = begin.line;
+                coord.column = begin.column + coord.column - end.column;
+            }
+            else
+                coord.line -= end.line - begin.line;
+        }
+        it = coord;
+    }
+};
+
+}
+
+void SelectionList::update_insert(const BufferCoord& begin, const BufferCoord& end)
+{
+    on_buffer_change<UpdateInsert>(*this, begin, end, begin.line);
+}
+
+void SelectionList::update_erase(const BufferCoord& begin, const BufferCoord& end)
+{
+    on_buffer_change<UpdateErase>(*this, begin, end, end.line);
+}
+
 }