remove Buffer:char_{distance,advance} use line access instead

src/buffer.cc

@@ -604,11 +604,6 @@ BufferCoord Buffer::advance(BufferCoord coord, ByteCount count) const
     return { LineCount{ (int)(it - m_lines.begin()) }, off - it->start };
 }
 
-BufferCoord Buffer::char_advance(BufferCoord coord, CharCount count) const
-{
-    return utf8::advance(iterator_at(coord), end(), count).coord();
-}
-
 BufferCoord Buffer::next(BufferCoord coord) const
 {
     if (coord.column < m_lines[coord.line].length() - 1)
@@ -675,11 +670,6 @@ ByteCount Buffer::distance(const BufferCoord& begin, const BufferCoord& end) con
     return offset(end) - offset(begin);
 }
 
-CharCount Buffer::char_distance(const BufferCoord& begin, const BufferCoord& end) const
-{
-    return utf8::distance(iterator_at(begin), iterator_at(end));
-}
-
 ByteCount Buffer::offset(const BufferCoord& c) const
 {
     if (c.line == line_count())

src/buffer.hh

@@ -119,8 +119,6 @@ public:
     BufferCoord    prev(BufferCoord coord) const;
 
     Codepoint      char_at(const BufferCoord& c) const;
-    CharCount      char_distance(const BufferCoord& begin, const BufferCoord& end) const;
-    BufferCoord    char_advance(BufferCoord coord, CharCount count) const;
     BufferCoord    char_next(BufferCoord coord) const;
     BufferCoord    char_prev(BufferCoord coord) const;
 

src/client_manager.cc

@@ -187,7 +187,7 @@ static DisplayLine generate_status_line(Client& client)
 {
     auto& context = client.context();
     auto pos = context.editor().main_selection().last();
-    auto col = context.buffer().char_distance({pos.line, 0}, pos);
+    auto col = context.buffer()[pos.line].char_count_to(pos.column);
 
     std::ostringstream oss;
     oss << context.buffer().display_name()

src/editor.cc

@@ -97,7 +97,7 @@ void Editor::insert(const String& str, InsertMode mode)
         {
             sel.first() = pos;
             sel.last()  = str.empty() ?
-                 pos : m_buffer->char_advance(pos, str.char_length() - 1);
+                 pos : m_buffer->advance(pos, str.byte_count_to(str.char_length() - 1));
         }
         avoid_eol(*m_buffer, sel);
     }
@@ -120,7 +120,7 @@ void Editor::insert(const memoryview<String>& strings, InsertMode mode)
         {
             sel.first() = pos;
             sel.last()  = str.empty() ?
-                 pos : m_buffer->char_advance(pos, str.char_length() - 1);
+                 pos : m_buffer->advance(pos, str.byte_count_to(str.char_length() - 1));
         }
         avoid_eol(*m_buffer, sel);
     }
@@ -185,8 +185,10 @@ void Editor::move_selections(CharCount offset, SelectMode mode)
     for (auto& sel : m_selections)
     {
         auto last = sel.last();
-        last = clamp<BufferCoord>(m_buffer->char_advance(last, offset),
+        auto& line = buffer()[last.line];
-                                  last.line, m_buffer->char_prev(last.line+1));
+        auto character = std::max(0_char, std::min(line.char_count_to(last.column) + offset,
+                                                   line.char_length() - 2));
+        last.column = line.byte_count_to(character);
         sel.first() = mode == SelectMode::Extend ? sel.first() : last;
         sel.last()  = last;
         avoid_eol(*m_buffer, sel);
@@ -199,12 +201,14 @@ void Editor::move_selections(LineCount offset, SelectMode mode)
     kak_assert(mode == SelectMode::Replace or mode == SelectMode::Extend);
     for (auto& sel : m_selections)
     {
-        CharCount column = m_buffer->char_distance(sel.last().line, sel.last());
+        auto character = (*m_buffer)[sel.last().line].char_count_to(sel.last().column);
         auto line = clamp(sel.last().line + offset, 0_line, m_buffer->line_count()-1);
-        column = std::min(column, (*m_buffer)[line].char_length()-1);
+        auto& content = (*m_buffer)[line];
-        BufferCoord last = m_buffer->char_advance(line, column);
+
-        sel.first() = mode == SelectMode::Extend ? sel.first() : last;
+        character = std::max(0_char, std::min(character, content.char_length() - 2));
-        sel.last()  = last;
+        BufferCoord pos{line, content.byte_count_to(character)};
+        sel.first() = mode == SelectMode::Extend ? sel.first() : pos;
+        sel.last()  = pos;
         avoid_eol(*m_buffer, sel);
     }
     sort_and_merge_overlapping(m_selections, m_main_sel);

src/normal.cc

@@ -707,7 +707,7 @@ void align(Context& context)
     auto& selections = context.editor().selections();
     auto& buffer = context.buffer();
     auto get_column = [&buffer](const BufferCoord& coord)
-    { return buffer.char_distance({coord.line, 0}, coord); };
+    { return buffer[coord.line].char_count_to(coord.column); };
 
     CharCount max_col = 0;
     for (auto& sel : selections)

src/window.cc

@@ -69,9 +69,9 @@ void Window::update_display_buffer()
         LineCount buffer_line = m_position.line + line;
         if (buffer_line >= buffer().line_count())
             break;
-        BufferCoord limit{buffer_line+1, 0};
+        const String& content = buffer()[buffer_line];
-        auto begin = std::min(buffer().char_advance(buffer_line, m_position.column), limit);
+        BufferCoord begin{buffer_line, content.byte_count_to(m_position.column)};
-        auto end   = std::min(buffer().char_advance(begin, m_dimensions.column), limit);
+        BufferCoord end{buffer_line, content.byte_count_to(m_position.column + m_dimensions.column)};
 
         lines.push_back(DisplayLine(buffer_line));
         lines.back().push_back(DisplayAtom(AtomContent(buffer(), begin, end)));
@@ -112,6 +112,7 @@ void Window::scroll_to_keep_cursor_visible_ifn()
 {
     const auto& first = main_selection().first();
     const auto& last  = main_selection().last();
+    const String& content = buffer()[last.line];
 
     const LineCount offset = std::min<LineCount>(options()["scrolloff"].get<int>(),
                                                  (m_dimensions.line - 1) / 2);
@@ -145,14 +146,14 @@ void Window::scroll_to_keep_cursor_visible_ifn()
         {
             column += atom.content.length();
 
-            CharCount first_col = first.line == last.line ?
+            auto first_col = (first.line == last.line) ? content.char_count_to(first.column) : 0_char;
-                                  buffer().char_distance(last.line, first) : 0_char;
+            auto last_col = content.char_count_to(last.column);
+
             if (first_col < m_position.column)
                 m_position.column = first_col;
             else if (column >= m_position.column + m_dimensions.column)
                 m_position.column = column - (m_dimensions.column - 1);
 
-            CharCount last_col = buffer().char_distance(last.line, last);
             if (last_col < m_position.column)
                 m_position.column = last_col;
             else if (column >= m_position.column + m_dimensions.column)