Remove undo group optimizer

1 files changed, 0 insertions, 188 deletions

diff --git a/src/buffer.cc b/src/buffer.cc
index 91f143c8..884ae270 100644
--- a/src/buffer.cc
+++ b/src/buffer.cc
@@ -181,200 +181,12 @@ struct Buffer::Modification
     }
 };
 
-class UndoGroupOptimizer
-{
-    static constexpr auto Insert = Buffer::Modification::Type::Insert;
-    static constexpr auto Erase = Buffer::Modification::Type::Erase;
-
-    static ByteCoord advance(ByteCoord coord, const String& str)
-    {
-        for (auto c : str)
-        {
-            if (c == '\n')
-            {
-                ++coord.line;
-                coord.column = 0;
-            }
-            else
-                ++coord.column;
-        }
-        return coord;
-    }
-
-    static ByteCount count_byte_to(ByteCoord pos, ByteCoord endpos, const String& str)
-    {
-        ByteCount count = 0;
-        for (auto it = str.begin(); it != str.end() and pos != endpos; ++it)
-        {
-            if (*it == '\n')
-            {
-                ++pos.line;
-                pos.column = 0;
-            }
-            else
-                ++pos.column;
-            ++count;
-        }
-        kak_assert(pos == endpos);
-        return count;
-    }
-
-    static const ByteCount overlaps(const String& lhs, const String& rhs)
-    {
-        if (lhs.empty() or rhs.empty())
-            return -1;
-
-        char c = rhs.front();
-        ByteCount pos = 0;
-        while ((pos = (int)lhs.find_first_of(c, (int)pos)) != -1)
-        {
-            ByteCount i = pos, j = 0;
-            while (i != lhs.length() and j != rhs.length() and lhs[i] == rhs[j])
-                 ++i, ++j;
-            if (i == lhs.length())
-                break;
-            ++pos;
-        }
-        return pos;
-    }
-
-    static bool merge_contiguous(Buffer::UndoGroup& undo_group)
-    {
-        bool progress = false;
-        auto it = undo_group.begin();
-        auto it_next = it+1;
-        while (it_next != undo_group.end())
-        {
-            ByteCount pos;
-            auto& coord = it->coord;
-            auto& next_coord = it_next->coord;
-
-            // reorders modification doing a kind of custom bubble sort
-            // so we have a O(n²) worst case complexity of the undo group optimization
-            if (next_coord < coord)
-            {
-                ByteCoord next_end = advance(next_coord, it_next->content);
-                if (it_next->type == Insert)
-                {
-                    if (coord.line == next_coord.line)
-                        coord.column += next_end.column - next_coord.column;
-                    coord.line += next_end.line - next_coord.line;
-                }
-                else if (it->type == Insert and next_end > coord)
-                {
-                    ByteCount start = count_byte_to(next_coord, coord, it_next->content);
-                    ByteCount len = std::min(it->content.length(), it_next->content.length() - start);
-                    kak_assert(it_next->content.substr(start, len) == it->content.substr(0, len));
-                    it->coord = it_next->coord;
-                    it->content = it->content.substr(len);
-                    it_next->content = it_next->content.substr(0,start) + it_next->content.substr(start + len);
-                }
-                else if (it->type == Erase and next_end >= coord)
-                {
-                    ByteCount start = count_byte_to(next_coord, coord, it_next->content);
-                    it_next->content = it_next->content.substr(0, start) + it->content + it_next->content.substr(start);
-                    it->coord = it_next->coord;
-                    it->content.clear();
-                }
-                else
-                {
-                    if (next_end.line == coord.line)
-                    {
-                        coord.line = next_coord.line;
-                        coord.column = next_coord.column + coord.column - next_end.column;
-                    }
-                    else
-                        coord.line -= next_end.line - next_coord.line;
-                }
-                std::swap(*it, *it_next);
-                progress = true;
-            }
-
-            kak_assert(coord <= next_coord);
-            if (it->type == Erase and it_next->type == Erase and coord == next_coord)
-            {
-                it->content += it_next->content;
-                it_next = undo_group.erase(it_next);
-                progress = true;
-            }
-            else if (it->type == Insert and it_next->type == Insert and
-                     is_in_range(next_coord, coord, advance(coord, it->content)))
-            {
-                ByteCount prefix_len = count_byte_to(coord, next_coord, it->content);
-                it->content = it->content.substr(0, prefix_len) + it_next->content
-                            + it->content.substr(prefix_len);
-                it_next = undo_group.erase(it_next);
-                progress = true;
-            }
-            else if (it->type == Insert and it_next->type == Erase and
-                     next_coord < advance(coord, it->content))
-            {
-                ByteCount insert_len = it->content.length();
-                ByteCount erase_len  = it_next->content.length();
-                ByteCount prefix_len = count_byte_to(coord, next_coord, it->content);
-
-                ByteCount suffix_len = insert_len - prefix_len;
-                if (suffix_len >= erase_len)
-                {
-                    it->content = it->content.substr(0, prefix_len) + it->content.substr(prefix_len + erase_len);
-                    it_next = undo_group.erase(it_next);
-                }
-                else
-                {
-                    it->content = it->content.substr(0, prefix_len);
-                    it_next->content = it_next->content.substr(suffix_len);
-                    ++it, ++it_next;
-                }
-                progress = true;
-            }
-            else if (it->type == Erase and it_next->type == Insert and coord == next_coord and
-                     (pos = overlaps(it->content, it_next->content)) != -1)
-            {
-                ByteCount overlaps_len = it->content.length() - pos;
-                it->content = it->content.substr(0, pos);
-                it_next->coord = advance(it_next->coord, it_next->content.substr(0, overlaps_len));
-                it_next->content = it_next->content.substr(overlaps_len);
-                ++it, ++it_next;
-                progress = true;
-            }
-            else
-                ++it, ++it_next;
-        }
-        return progress;
-    }
-
-    static bool erase_empty(Buffer::UndoGroup& undo_group)
-    {
-        auto it = std::remove_if(begin(undo_group), end(undo_group),
-                                 [](Buffer::Modification& m) { return m.content.empty(); });
-        if (it != end(undo_group))
-        {
-            undo_group.erase(it, end(undo_group));
-            return true;
-        }
-        return false;
-    }
-public:
-    static void optimize(Buffer::UndoGroup& undo_group)
-    {
-        while (undo_group.size() > 1)
-        {
-            bool progress = false;
-            progress |= merge_contiguous(undo_group);
-            progress |= erase_empty(undo_group);
-            if (not progress)
-                break;
-        }
-    }
-};
 
 void Buffer::commit_undo_group()
 {
     if (m_flags & Flags::NoUndo)
         return;
 
-    UndoGroupOptimizer::optimize(m_current_undo_group);
-
     if (m_current_undo_group.empty())
         return;