Use coord instead of iterators for selections

13 files changed, 174 insertions, 163 deletions

diff --git a/src/client_manager.cc b/src/client_manager.cc
index 10bbbc69..c4dbda6f 100644
--- a/src/client_manager.cc
+++ b/src/client_manager.cc
@@ -187,11 +187,11 @@ static DisplayLine generate_status_line(Client& client)
 {
     auto& context = client.context();
     auto pos = context.editor().main_selection().last();
-    auto col = utf8::distance(context.buffer().iterator_at_line_begin(pos), pos);
+    auto col = context.buffer().char_distance({pos.line, 0}, pos);
 
     std::ostringstream oss;
     oss << context.buffer().display_name()
-        << " " << (int)pos.line()+1 << ":" << (int)col+1;
+        << " " << (int)pos.line+1 << ":" << (int)col+1;
     if (context.buffer().is_modified())
         oss << " [+]";
     if (context.input_handler().is_recording())
diff --git a/src/dynamic_selection_list.cc b/src/dynamic_selection_list.cc
index 3de8c80c..dfc78436 100644
--- a/src/dynamic_selection_list.cc
+++ b/src/dynamic_selection_list.cc
@@ -30,8 +30,8 @@ void DynamicSelectionList::check_invariant() const
         kak_assert(buffer.is_valid(sel.last()));
         kak_assert(not buffer.is_end(sel.first()));
         kak_assert(not buffer.is_end(sel.last()));
-        kak_assert(utf8::is_character_start(sel.first()));
-        kak_assert(utf8::is_character_start(sel.last()));
+        kak_assert(utf8::is_character_start(buffer.iterator_at(sel.first())));
+        kak_assert(utf8::is_character_start(buffer.iterator_at(sel.last())));
     }
 #endif
 }
diff --git a/src/editor.cc b/src/editor.cc
index 0de58d5e..fa569d00 100644
--- a/src/editor.cc
+++ b/src/editor.cc
@@ -20,17 +20,17 @@ Editor::Editor(Buffer& buffer)
     m_main_sel = 0;
 }
 
-static void avoid_eol(BufferIterator& it)
+static void avoid_eol(const Buffer& buffer, BufferCoord& coord)
 {
-    const auto column = it.column();
-    if (column != 0 and column == it.buffer().line_length(it.line()) - 1)
-        it = utf8::previous(it);
+    const auto column = coord.column;
+    if (column != 0 and column == buffer.line_length(coord.line) - 1)
+        coord = buffer.char_prev(coord);
 }
 
-static void avoid_eol(Selection& sel)
+static void avoid_eol(const Buffer& buffer, Range& sel)
 {
-    avoid_eol(sel.first());
-    avoid_eol(sel.last());
+    avoid_eol(buffer, sel.first());
+    avoid_eol(buffer, sel.last());
 }
 
 void Editor::erase()
@@ -38,13 +38,13 @@ void Editor::erase()
     scoped_edition edition(*this);
     for (auto& sel : m_selections)
     {
-        m_buffer->erase(sel.min(), utf8::next(sel.max()));
-        avoid_eol(sel);
+        Kakoune::erase(*m_buffer, sel);
+        avoid_eol(*m_buffer, sel);
     }
 }
 
-static BufferIterator prepare_insert(Buffer& buffer, const Selection& sel,
-                                     InsertMode mode)
+static BufferCoord prepare_insert(Buffer& buffer, const Selection& sel,
+                                  InsertMode mode)
 {
     switch (mode)
     {
@@ -52,37 +52,37 @@ static BufferIterator prepare_insert(Buffer& buffer, const Selection& sel,
         return sel.min();
     case InsertMode::Replace:
     {
-        BufferIterator pos = sel.min();
-        buffer.erase(sel.min(), utf8::next(sel.max()));
+        BufferCoord pos = sel.min();
+        Kakoune::erase(buffer, sel);
         return pos;
     }
     case InsertMode::Append:
     {
         // special case for end of lines, append to current line instead
         auto pos = std::max(sel.first(), sel.last());
-        if (pos.column() == buffer.line_length(pos.line()) - 1)
+        if (pos.column == buffer.line_length(pos.line) - 1)
             return pos;
         else
-            return utf8::next(pos);
+            return buffer.char_next(pos);
     }
     case InsertMode::InsertAtLineBegin:
-        return buffer.iterator_at_line_begin(sel.min());
+        return sel.min().line;
     case InsertMode::AppendAtLineEnd:
-        return buffer.iterator_at_line_end(sel.max())-1;
+        return buffer.char_prev(sel.max().line+1);
     case InsertMode::InsertAtNextLineBegin:
-        return buffer.iterator_at_line_end(sel.max());
+        return sel.max().line+1;
     case InsertMode::OpenLineBelow:
     case InsertMode::OpenLineAbove:
     {
         auto line = mode == InsertMode::OpenLineAbove ?
-            sel.min().line() : sel.max().line() + 1;
+            sel.min().line : sel.max().line + 1;
         buffer.insert(line, "\n");
-        return {buffer, line};
+        return line;
     }
 
     }
     kak_assert(false);
-    return BufferIterator{};
+    return {};
 }
 
 void Editor::insert(const String& str, InsertMode mode)
@@ -91,14 +91,15 @@ void Editor::insert(const String& str, InsertMode mode)
 
     for (auto& sel : m_selections)
     {
-        BufferIterator pos = prepare_insert(*m_buffer, sel, mode);
+        BufferCoord pos = prepare_insert(*m_buffer, sel, mode);
         m_buffer->insert(pos, str);
-        if (mode == InsertMode::Replace and not pos.is_end())
+        if (mode == InsertMode::Replace and not m_buffer->is_end(pos))
         {
             sel.first() = pos;
-            sel.last() = str.empty() ? pos : utf8::character_start(pos + str.length() - 1);
+            sel.last()  = str.empty() ?
+                 pos : m_buffer->char_advance(pos, str.char_length() - 1);
         }
-        avoid_eol(sel);
+        avoid_eol(*m_buffer, sel);
     }
     check_invariant();
 }
@@ -112,15 +113,16 @@ void Editor::insert(const memoryview<String>& strings, InsertMode mode)
     for (size_t i = 0; i < selections().size(); ++i)
     {
         auto& sel = m_selections[i];
-        BufferIterator pos = prepare_insert(*m_buffer, sel, mode);
+        BufferCoord pos = prepare_insert(*m_buffer, sel, mode);
         const String& str = strings[std::min(i, strings.size()-1)];
         m_buffer->insert(pos, str);
-        if (mode == InsertMode::Replace and not pos.is_end())
+        if (mode == InsertMode::Replace and not m_buffer->is_end(pos))
         {
             sel.first() = pos;
-            sel.last() = str.empty() ? pos : utf8::character_start(pos + str.length() - 1);
+            sel.last()  = str.empty() ?
+                 pos : m_buffer->char_advance(pos, str.char_length() - 1);
         }
-        avoid_eol(sel);
+        avoid_eol(*m_buffer, sel);
     }
     check_invariant();
 }
@@ -129,7 +131,7 @@ std::vector<String> Editor::selections_content() const
 {
     std::vector<String> contents;
     for (auto& sel : m_selections)
-        contents.push_back(m_buffer->string(sel.min(), utf8::next(sel.max())));
+        contents.push_back(m_buffer->string(sel.min(), m_buffer->char_next(sel.max())));
     return contents;
 }
 
@@ -183,12 +185,11 @@ void Editor::move_selections(CharCount offset, SelectMode mode)
     for (auto& sel : m_selections)
     {
         auto last = sel.last();
-        auto limit = offset < 0 ? buffer().iterator_at_line_begin(last)
-                                : utf8::previous(buffer().iterator_at_line_end(last));
-        last = utf8::advance(last, limit, offset);
+        last = clamp<BufferCoord>(m_buffer->char_advance(last, offset),
+                                  last.line, m_buffer->char_prev(last.line+1));
         sel.first() = mode == SelectMode::Extend ? sel.first() : last;
         sel.last()  = last;
-        avoid_eol(sel);
+        avoid_eol(*m_buffer, sel);
     }
     sort_and_merge_overlapping(m_selections, m_main_sel);
 }
@@ -198,14 +199,14 @@ void Editor::move_selections(LineCount offset, SelectMode mode)
     kak_assert(mode == SelectMode::Replace or mode == SelectMode::Extend);
     for (auto& sel : m_selections)
     {
-        BufferCoord pos = sel.last().coord();
-        CharCount column = utf8::distance(m_buffer->iterator_at_line_begin(pos.line), sel.last());
+        auto pos = sel.last();
+        CharCount column = m_buffer->char_distance(pos.line, pos);
         pos.line += offset;
-        BufferIterator last = utf8::advance(m_buffer->iterator_at_line_begin(pos.line),
-                                            m_buffer->iterator_at_line_end(pos.line)-1, column);
+        auto last = std::min(m_buffer->char_advance(pos.line, column),
+                             m_buffer->char_prev(pos.line+1));
         sel.first() = mode == SelectMode::Extend ? sel.first() : last;
         sel.last()  = last;
-        avoid_eol(sel);
+        avoid_eol(*m_buffer, sel);
     }
     sort_and_merge_overlapping(m_selections, m_main_sel);
 }
@@ -215,8 +216,8 @@ void Editor::clear_selections()
     auto& sel = m_selections[m_main_sel];
     auto& pos = sel.last();
 
-    if (*pos == '\n' and not pos.is_begin() and *utf8::previous(pos) != '\n')
-        pos = utf8::previous(pos);
+    if (pos.column != 0 and pos.column == m_buffer->line_length(pos.line) - 1)
+        pos = m_buffer->char_prev(pos);
     sel.first() = pos;
 
     m_selections.erase(m_selections.begin(), m_selections.begin() + m_main_sel);
@@ -392,21 +393,22 @@ private:
     SelectionList m_ranges;
 };
 
-inline bool touches(const Range& lhs, const Range& rhs)
+inline bool touches(const Buffer& buffer, const Range& lhs, const Range& rhs)
 {
-    return lhs.min() <= rhs.min() ? utf8::next(lhs.max()) >= rhs.min()
-                                  : lhs.min() <= utf8::next(rhs.max());
+    return lhs.min() <= rhs.min() ? buffer.char_next(lhs.max()) >= rhs.min()
+                                  : lhs.min() <= buffer.char_next(rhs.max());
 }
 
 bool Editor::undo()
 {
+    using namespace std::placeholders;
     ModifiedRangesListener listener(buffer());
     bool res = m_buffer->undo();
     if (res and not listener.ranges().empty())
     {
         m_selections = std::move(listener.ranges());
         m_main_sel = m_selections.size() - 1;
-        merge_overlapping(m_selections, m_main_sel, touches);
+        merge_overlapping(m_selections, m_main_sel, std::bind(touches, std::ref(buffer()), _1, _2));
     }
     check_invariant();
     return res;
@@ -414,13 +416,14 @@ bool Editor::undo()
 
 bool Editor::redo()
 {
+    using namespace std::placeholders;
     ModifiedRangesListener listener(buffer());
     bool res = m_buffer->redo();
     if (res and not listener.ranges().empty())
     {
         m_selections = std::move(listener.ranges());
         m_main_sel = m_selections.size() - 1;
-        merge_overlapping(m_selections, m_main_sel, touches);
+        merge_overlapping(m_selections, m_main_sel, std::bind(touches, std::ref(buffer()), _1, _2));
     }
     check_invariant();
     return res;
@@ -463,17 +466,17 @@ IncrementalInserter::IncrementalInserter(Editor& editor, InsertMode mode)
         utf8_it first, last;
         switch (mode)
         {
-        case InsertMode::Insert:  first = sel.max(); last = sel.min(); break;
+        case InsertMode::Insert:  first = buffer.iterator_at(sel.max()); last = buffer.iterator_at(sel.min()); break;
         case InsertMode::Replace:
         {
-            buffer.erase(sel.min(), utf8::next(sel.max()));
-            first = last = sel.min();
+            Kakoune::erase(buffer, sel);
+            first = last = buffer.iterator_at(sel.min());
             break;
         }
         case InsertMode::Append:
         {
-            first = sel.min();
-            last  = std::max(sel.first(), sel.last());
+            first = buffer.iterator_at(sel.min());
+            last  = buffer.iterator_at(sel.max());
             // special case for end of lines, append to current line instead
             auto coord = last.underlying_iterator().coord();
             if (coord.column != buffer.line_length(coord.line) - 1)
@@ -483,13 +486,13 @@ IncrementalInserter::IncrementalInserter(Editor& editor, InsertMode mode)
 
         case InsertMode::OpenLineBelow:
         case InsertMode::AppendAtLineEnd:
-            first = utf8_it(buffer.iterator_at_line_end(sel.max())) - 1;
+            first = utf8_it(buffer.iterator_at(sel.max().line+1)) - 1;
             last  = first;
             break;
 
         case InsertMode::OpenLineAbove:
         case InsertMode::InsertAtLineBegin:
-            first = buffer.iterator_at_line_begin(sel.min());
+            first = buffer.iterator_at(sel.min().line);
             if (mode == InsertMode::OpenLineAbove)
                 --first;
             else
@@ -534,9 +537,9 @@ IncrementalInserter::~IncrementalInserter()
 {
     for (auto& sel : m_editor.m_selections)
     {
-        if (m_mode == InsertMode::Append and sel.last().column() > 0)
-            sel.last() = utf8::previous(sel.last());
-        avoid_eol(sel);
+        if (m_mode == InsertMode::Append and sel.last().column > 0)
+            sel.last() = m_editor.buffer().char_prev(sel.last());
+        avoid_eol(m_editor.buffer(), sel);
     }
 }
 
@@ -564,8 +567,8 @@ void IncrementalInserter::erase()
 {
     for (auto& sel : m_editor.m_selections)
     {
-        BufferIterator pos = sel.last();
-        m_editor.buffer().erase(utf8::previous(pos), pos);
+        BufferCoord pos = sel.last();
+        m_editor.buffer().erase(m_editor.buffer().char_prev(pos), pos);
     }
 }
 
diff --git a/src/filters.cc b/src/filters.cc
index ae6aa760..53f6576d 100644
--- a/src/filters.cc
+++ b/src/filters.cc
@@ -10,7 +10,7 @@ void preserve_indent(Buffer& buffer, Selection& selection, String& content)
 {
     if (content == "\n")
     {
-        BufferCoord line_begin{selection.last().line(), 0};
+        BufferCoord line_begin{selection.last().line, 0};
         auto first_non_white = buffer.iterator_at(line_begin);
         while ((*first_non_white == '\t' or *first_non_white == ' ') and
                not first_non_white.is_end())
@@ -82,12 +82,12 @@ struct RegexFilter
                     String suffix(it+1, content.end());
                     content = String(content.begin(), it-1);
 
-                    auto first = selection.first();
-                    auto last = selection.last();
+                    auto& first = selection.first();
+                    auto& last = selection.last();
                     buffer.insert(position, suffix);
-                    if (selection.first() == selection.last())
-                        selection.first() -= suffix.length();
-                    selection.last() -= suffix.length();
+                    if (first == last)
+                        first = buffer.advance(first, -suffix.length());
+                    last = buffer.advance(last, -suffix.length());
                 }
             }
         }
diff --git a/src/highlighters.cc b/src/highlighters.cc
index edd3d7d3..064c1660 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -280,22 +280,23 @@ void show_line_numbers(const Window& window, DisplayBuffer& display_buffer)
 void highlight_selections(const Window& window, DisplayBuffer& display_buffer)
 {
     const bool only_cursor = window.is_editing() and window.options()["insert_hide_sel"].get<bool>();
+    const auto& buffer = window.buffer();
     for (size_t i = 0; i < window.selections().size(); ++i)
     {
         auto& sel = window.selections()[i];
         const bool forward = sel.first() <= sel.last();
-        BufferIterator begin = forward ? sel.first() : utf8::next(sel.last());
-        BufferIterator end   = forward ? sel.last() : utf8::next(sel.first());
+        BufferCoord begin = forward ? sel.first() : buffer.char_next(sel.last());
+        BufferCoord end   = forward ? sel.last() : buffer.char_next(sel.first());
 
         const bool primary = (i == window.main_selection_index());
         if (not only_cursor)
         {
             ColorPair sel_colors = get_color(primary ? "PrimarySelection" : "SecondarySelection");
-            highlight_range(display_buffer, begin.coord(), end.coord(), false,
+            highlight_range(display_buffer, begin, end, false,
                             [&](DisplayAtom& atom) { atom.colors = sel_colors; });
         }
         ColorPair cur_colors = get_color(primary ? "PrimaryCursor" : "SecondaryCursor");
-        highlight_range(display_buffer, sel.last().coord(), utf8::next(sel.last()).coord(), false,
+        highlight_range(display_buffer, sel.last(), buffer.char_next(sel.last()), false,
                         [&](DisplayAtom& atom) { atom.colors = cur_colors; });
     }
 }
diff --git a/src/input_handler.cc b/src/input_handler.cc
index d76d3b14..fd2be75c 100644
--- a/src/input_handler.cc
+++ b/src/input_handler.cc
@@ -610,11 +610,13 @@ public:
         for (auto& sel : m_context.editor().selections())
         {
             auto offset = buffer.offset(sel.last());
+            auto pos = buffer.iterator_at(sel.last());
             if (offset >= beg_offset and offset + end_offset < buffer_len and
-                std::equal(sel.last() - beg_offset, sel.last(), begin))
+                std::equal(pos - beg_offset, pos, begin))
             {
-                buffer.erase(sel.last() - beg_offset, sel.last() + end_offset);
-                buffer.insert(sel.last(), candidate);
+                auto beg = pos - beg_offset;
+                buffer.erase(beg, pos + end_offset);
+                buffer.insert(beg, candidate);
             }
         }
 
diff --git a/src/main.cc b/src/main.cc
index fc196564..980438a5 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -68,7 +68,7 @@ void register_env_vars()
     shell_manager.register_env_var("selection",
                                    [](const String& name, const Context& context)
                                    { const Range& sel = context.editor().main_selection();
-                                     return context.buffer().string(sel.min(), utf8::next(sel.max())); });
+                                     return content(context.buffer(), sel); });
     shell_manager.register_env_var("selections",
                                    [](const String& name, const Context& context)
                                    { auto sels = context.editor().selections_content();
@@ -91,15 +91,15 @@ void register_env_vars()
                                    { return ClientManager::instance().get_client(context).name(); });
     shell_manager.register_env_var("cursor_line",
                                    [](const String& name, const Context& context)
-                                   { return to_string(context.editor().main_selection().last().line() + 1); });
+                                   { return to_string(context.editor().main_selection().last().line + 1); });
     shell_manager.register_env_var("cursor_column",
                                    [](const String& name, const Context& context)
-                                   { return to_string(context.editor().main_selection().last().column() + 1); });
+                                   { return to_string(context.editor().main_selection().last().column + 1); });
     shell_manager.register_env_var("selection_desc",
                                    [](const String& name, const Context& context)
                                    { auto& sel = context.editor().main_selection();
                                      auto beg = sel.min();
-                                     return to_string(beg.line() + 1) + ':' + to_string(beg.column() + 1) + '+' +
+                                     return to_string(beg.line + 1) + ':' + to_string(beg.column + 1) + '+' +
                                             to_string((int)context.buffer().distance(beg, sel.max())+1); });
     shell_manager.register_env_var("window_width",
                                    [](const String& name, const Context& context)
diff --git a/src/normal.cc b/src/normal.cc
index 0204dc3a..65347c48 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -136,14 +136,15 @@ void goto_commands(Context& context)
             case 'f':
             {
                 const Range& sel = context.editor().main_selection();
-                String filename = context.buffer().string(sel.min(), utf8::next(sel.max()));
+                const Buffer& buffer = context.buffer();
+                String filename = content(buffer, sel);
                 static constexpr char forbidden[] = { '\'', '\\', '\0' };
                 for (auto c : forbidden)
                     if (contains(filename, c))
                         return;
 
                 auto paths = context.options()["path"].get<std::vector<String>>();
-                const String& buffer_name = context.buffer().name();
+                const String& buffer_name = buffer.name();
                 auto it = find(reversed(buffer_name), '/');
                 if (it != buffer_name.rend())
                     paths.insert(paths.begin(), String{buffer_name.begin(), it.base()});
@@ -248,7 +249,7 @@ void pipe(Context& context)
             Editor& editor = context.editor();
             std::vector<String> strings;
             for (auto& sel : context.editor().selections())
-                strings.push_back(ShellManager::instance().pipe({sel.min(), utf8::next(sel.max())},
+                strings.push_back(ShellManager::instance().pipe(content(context.buffer(), sel),
                                                                 cmdline, context, {},
                                                                 EnvVarMap{}));
             editor.insert(strings, InsertMode::Replace);
@@ -332,20 +333,21 @@ void use_selection_as_search_pattern(Context& context)
 {
     std::vector<String> patterns;
     auto& sels = context.editor().selections();
+    const auto& buffer = context.buffer();
     for (auto& sel : sels)
     {
         auto begin = sel.min();
-        auto end = utf8::next(sel.max());
+        auto end = buffer.char_next(sel.max());
         auto content = "\\Q" + context.buffer().string(begin, end) + "\\E";
         if (smart)
         {
-            if (begin.is_begin() or
-                (is_word(utf8::codepoint(begin)) and not
-                 is_word(utf8::codepoint(utf8::previous(begin)))))
+            if (begin == BufferCoord{0,0} or
+                (is_word(buffer.char_at(begin)) and not
+                 is_word(buffer.char_at(buffer.char_prev(begin)))))
                 content = "\\b" + content;
-            if (end.is_end() or
-                (is_word(utf8::codepoint(utf8::previous(end))) and not
-                 is_word(utf8::codepoint(end))))
+            if (buffer.is_end(end) or
+                (is_word(buffer.char_at(buffer.char_prev(end))) and not
+                 is_word(buffer.char_at(end))))
                 content = content + "\\b";
         }
         patterns.push_back(std::move(content));
@@ -371,7 +373,7 @@ void cat_yank(Context& context)
                            to_string(sels.size()) + " selections", get_color("Information") });
 }
 
-void erase(Context& context)
+void erase_selections(Context& context)
 {
     RegisterManager::instance()['"'] = context.editor().selections_content();
     context.editor().erase();
@@ -478,7 +480,7 @@ void join_select_spaces(Context& context)
         kak_assert(std::is_sorted(res.begin(), res.end(),
               [](const Selection& lhs, const Selection& rhs)
               { return lhs.min() < rhs.min(); }));
-        if (not res.empty() and utf8::next(res.back().max()).is_end())
+        if (not res.empty() and buffer.is_end(buffer.char_next(res.back().max())))
             res.pop_back();
         return res;
     });
@@ -499,11 +501,13 @@ void keep(Context& context)
     constexpr const char* prompt = matching ? "keep matching:" : "keep not matching:";
     regex_prompt(context, prompt, [](const Regex& ex, Context& context) {
         Editor& editor = context.editor();
+        const Buffer& buffer = context.buffer();
         SelectionList sels = editor.selections();
         SelectionList keep;
         for (auto& sel : sels)
         {
-            if (boost::regex_search(sel.min(), utf8::next(sel.max()), ex) == matching)
+            if (boost::regex_search(buffer.iterator_at(sel.min()),
+                                    utf8::next(buffer.iterator_at(sel.max())), ex) == matching)
                 keep.push_back(sel);
         }
         if (keep.empty())
@@ -703,8 +707,8 @@ void align(Context& context)
 {
     auto& selections = context.editor().selections();
     auto& buffer = context.buffer();
-    auto get_column = [&buffer](const BufferIterator& it)
-    { return utf8::distance(buffer.iterator_at_line_begin(it), it); };
+    auto get_column = [&buffer](const BufferCoord& coord)
+    { return buffer.char_distance({coord.line, 0}, coord); };
 
     CharCount max_col = 0;
     for (auto& sel : selections)
@@ -774,7 +778,7 @@ KeyMap keymap =
     { { Key::Modifiers::Alt,  'T' }, select_to_next_char<SelectFlags::Extend | SelectFlags::Reverse> },
     { { Key::Modifiers::Alt,  'F' }, select_to_next_char<SelectFlags::Inclusive | SelectFlags::Extend | SelectFlags::Reverse> },
 
-    { { Key::Modifiers::None, 'd' }, erase },
+    { { Key::Modifiers::None, 'd' }, erase_selections },
     { { Key::Modifiers::None, 'c' }, change },
     { { Key::Modifiers::None, 'i' }, insert<InsertMode::Insert> },
     { { Key::Modifiers::None, 'I' }, insert<InsertMode::InsertAtLineBegin> },
diff --git a/src/selection.cc b/src/selection.cc
index 0a4c4e32..f7360e7f 100644
--- a/src/selection.cc
+++ b/src/selection.cc
@@ -22,9 +22,9 @@ void on_buffer_change(const Buffer& buffer, 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().coord(), s.last().coord()) < c; });
+                                       [](const Selection& s, const BufferCoord& c) { return std::max(s.first(), s.last()) < 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().coord(), s.last().coord()).line; });
+                                                 [](LineCount l, const Selection& s) { return l < std::min(s.first(), s.last()).line; });
 
     if (update_beg != update_only_line_beg)
     {
@@ -50,10 +50,9 @@ void on_buffer_change(const Buffer& buffer, SelectionList& sels,
 template<bool assume_different_line, bool assume_greater_than_begin>
 struct UpdateInsert
 {
-    void operator()(const Buffer& buffer, BufferIterator& it,
+    void operator()(const Buffer& buffer, BufferCoord& coord,
                     const BufferCoord& begin, const BufferCoord& end) const
     {
-        auto coord = it.coord();
         if (assume_different_line)
             kak_assert(begin.line < coord.line);
         if (not assume_greater_than_begin and coord < begin)
@@ -62,17 +61,15 @@ struct UpdateInsert
             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()(const Buffer& buffer, BufferIterator& it,
+    void operator()(const Buffer& buffer, BufferCoord& coord,
                     const BufferCoord& begin, const BufferCoord& end) const
     {
-        auto coord = it.coord();
         if (not assume_greater_than_begin and coord < begin)
             return;
         if (assume_different_line)
@@ -89,7 +86,6 @@ struct UpdateErase
             else
                 coord.line -= end.line - begin.line;
         }
-        it = coord;
     }
 };
 
diff --git a/src/selection.hh b/src/selection.hh
index e8754df5..c7e5e2c3 100644
--- a/src/selection.hh
+++ b/src/selection.hh
@@ -10,28 +10,28 @@ namespace Kakoune
 struct Range
 {
 public:
-    Range(const BufferIterator& first, const BufferIterator& last)
+    Range(const BufferCoord& first, const BufferCoord& last)
         : m_first{first}, m_last{last} {}
 
     void merge_with(const Range& range);
 
-    BufferIterator& first() { return m_first; }
-    BufferIterator& last() { return m_last; }
+    BufferCoord& first() { return m_first; }
+    BufferCoord& last() { return m_last; }
 
-    const BufferIterator& first() const { return m_first; }
-    const BufferIterator& last() const { return m_last; }
+    const BufferCoord& first() const { return m_first; }
+    const BufferCoord& last() const { return m_last; }
 
     bool operator== (const Range& other) const
     {
         return m_first == other.m_first and m_last == other.m_last;
     }
 
-    const BufferIterator& min() const { return std::min(m_first, m_last); }
-    const BufferIterator& max() const { return std::max(m_first, m_last); }
+    const BufferCoord& min() const { return std::min(m_first, m_last); }
+    const BufferCoord& max() const { return std::max(m_first, m_last); }
 
 private:
-    BufferIterator m_first;
-    BufferIterator m_last;
+    BufferCoord m_first;
+    BufferCoord m_last;
 };
 
 inline bool overlaps(const Range& lhs, const Range& rhs)
@@ -40,12 +40,22 @@ inline bool overlaps(const Range& lhs, const Range& rhs)
                                   : lhs.min() <= rhs.max();
 }
 
+inline String content(const Buffer& buffer, const Range& range)
+{
+    return buffer.string(range.min(), buffer.char_next(range.max()));
+}
+
+inline void erase(Buffer& buffer, const Range& range)
+{
+    return buffer.erase(range.min(), buffer.char_next(range.max()));
+}
+
 using CaptureList = std::vector<String>;
 
 // A selection is a Range, associated with a CaptureList
 struct Selection : public Range
 {
-    Selection(const BufferIterator& first, const BufferIterator& last,
+    Selection(const BufferCoord& first, const BufferCoord& last,
               CaptureList captures = {})
         : Range(first, last), m_captures(std::move(captures)) {}
 
diff --git a/src/selectors.cc b/src/selectors.cc
index ae9f7397..c2e7e62f 100644
--- a/src/selectors.cc
+++ b/src/selectors.cc
@@ -85,7 +85,7 @@ typedef boost::regex_iterator<BufferIterator> RegexIterator;
 template<bool punctuation_is_word>
 Selection select_to_next_word(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
     if (categorize<punctuation_is_word>(*begin) !=
         categorize<punctuation_is_word>(*(begin+1)))
         ++begin;
@@ -108,7 +108,7 @@ template Selection select_to_next_word<true>(const Buffer&, const Selection&);
 template<bool punctuation_is_word>
 Selection select_to_next_word_end(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
     if (categorize<punctuation_is_word>(*begin) !=
         categorize<punctuation_is_word>(*(begin+1)))
         ++begin;
@@ -130,7 +130,7 @@ template Selection select_to_next_word_end<true>(const Buffer&, const Selection&
 template<bool punctuation_is_word>
 Selection select_to_previous_word(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
 
     if (categorize<punctuation_is_word>(*begin) !=
         categorize<punctuation_is_word>(*(begin-1)))
@@ -159,7 +159,7 @@ template Selection select_to_previous_word<true>(const Buffer&, const Selection&
 
 Selection select_line(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator first = selection.last();
+    Utf8Iterator first = buffer.iterator_at(selection.last());
     if (*first == '\n' and not is_end(first + 1))
         ++first;
 
@@ -175,7 +175,7 @@ Selection select_line(const Buffer& buffer, const Selection& selection)
 Selection select_matching(const Buffer& buffer, const Selection& selection)
 {
     std::vector<Codepoint> matching_pairs = { '(', ')', '{', '}', '[', ']', '<', '>' };
-    Utf8Iterator it = selection.last();
+    Utf8Iterator it = buffer.iterator_at(selection.last());
     std::vector<Codepoint>::iterator match = matching_pairs.end();
     while (not is_eol(*it))
     {
@@ -289,15 +289,15 @@ Selection select_surrounding(const Buffer& buffer, const Selection& selection,
                              const CodepointPair& matching,
                              ObjectFlags flags)
 {
-    auto res = find_surrounding(selection.last(), matching, flags);
+    auto res = find_surrounding(buffer.iterator_at(selection.last()), matching, flags);
     if (not res)
         return selection;
 
     if (flags == (ObjectFlags::ToBegin | ObjectFlags::ToEnd) and
-        matching.first != matching.second and not res->last().is_end() and
+        matching.first != matching.second and not buffer.is_end(res->last()) and
         (*res == selection or Range{res->last(), res->first()} == selection))
     {
-        res = find_surrounding(res->last() + 1, matching, flags);
+        res = find_surrounding(buffer.iterator_at(res->last()) + 1, matching, flags);
         return res ? Selection{*res} : selection;
     }
     return *res;
@@ -306,7 +306,7 @@ Selection select_surrounding(const Buffer& buffer, const Selection& selection,
 Selection select_to(const Buffer& buffer, const Selection& selection,
                     Codepoint c, int count, bool inclusive)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
     Utf8Iterator end = begin;
     do
     {
@@ -323,7 +323,7 @@ Selection select_to(const Buffer& buffer, const Selection& selection,
 Selection select_to_reverse(const Buffer& buffer, const Selection& selection,
                             Codepoint c, int count, bool inclusive)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
     Utf8Iterator end = begin;
     do
     {
@@ -339,7 +339,7 @@ Selection select_to_reverse(const Buffer& buffer, const Selection& selection,
 
 Selection select_to_eol(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
     Utf8Iterator end = begin + 1;
     skip_while(end, [](Codepoint cur) { return not is_eol(cur); });
     return utf8_range(begin, end-1);
@@ -347,7 +347,7 @@ Selection select_to_eol(const Buffer& buffer, const Selection& selection)
 
 Selection select_to_eol_reverse(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = selection.last();
+    Utf8Iterator begin = buffer.iterator_at(selection.last());
     Utf8Iterator end = begin - 1;
     skip_while_reverse(end, [](Codepoint cur) { return not is_eol(cur); });
     return utf8_range(begin, is_begin(end) ? end : end+1);
@@ -356,7 +356,7 @@ Selection select_to_eol_reverse(const Buffer& buffer, const Selection& selection
 template<bool punctuation_is_word>
 Selection select_whole_word(const Buffer& buffer, const Selection& selection, ObjectFlags flags)
 {
-    Utf8Iterator first = selection.last();
+    Utf8Iterator first = buffer.iterator_at(selection.last());
     Utf8Iterator last = first;
     if (is_word<punctuation_is_word>(*first))
     {
@@ -399,7 +399,7 @@ template Selection select_whole_word<true>(const Buffer&, const Selection&, Obje
 
 Selection select_whole_sentence(const Buffer& buffer, const Selection& selection, ObjectFlags flags)
 {
-    BufferIterator first = selection.last();
+    BufferIterator first = buffer.iterator_at(selection.last());
     BufferIterator last = first;
 
     if (flags & ObjectFlags::ToBegin)
@@ -450,7 +450,7 @@ Selection select_whole_sentence(const Buffer& buffer, const Selection& selection
 
 Selection select_whole_paragraph(const Buffer& buffer, const Selection& selection, ObjectFlags flags)
 {
-    BufferIterator first = selection.last();
+    BufferIterator first = buffer.iterator_at(selection.last());
     BufferIterator last = first;
 
     if (flags & ObjectFlags::ToBegin and not is_begin(first))
@@ -493,8 +493,8 @@ Selection select_whole_paragraph(const Buffer& buffer, const Selection& selectio
 Selection select_whole_lines(const Buffer& buffer, const Selection& selection)
 {
     // no need to be utf8 aware for is_eol as we only use \n as line seperator
-    BufferIterator first = selection.first();
-    BufferIterator last =  selection.last();
+    BufferIterator first = buffer.iterator_at(selection.first());
+    BufferIterator last  = buffer.iterator_at(selection.last());
     BufferIterator& to_line_start = first <= last ? first : last;
     BufferIterator& to_line_end = first <= last ? last : first;
 
@@ -513,8 +513,8 @@ Selection select_whole_lines(const Buffer& buffer, const Selection& selection)
 Selection trim_partial_lines(const Buffer& buffer, const Selection& selection)
 {
     // same as select_whole_lines
-    BufferIterator first = selection.first();
-    BufferIterator last =  selection.last();
+    BufferIterator first = buffer.iterator_at(selection.first());
+    BufferIterator last =  buffer.iterator_at(selection.last());
     BufferIterator& to_line_start = first <= last ? first : last;
     BufferIterator& to_line_end = first <= last ? last : first;
 
@@ -565,7 +565,7 @@ Selection select_next_match(const Buffer& buffer, const Selection& selection, co
 {
     // regex matching do not use Utf8Iterator as boost::regex handle utf8
     // decoding itself
-    BufferIterator begin = selection.last();
+    BufferIterator begin = buffer.iterator_at(selection.last());
     BufferIterator end = begin;
     CaptureList captures;
 
@@ -594,8 +594,8 @@ template Selection select_next_match<false>(const Buffer&, const Selection&, con
 
 SelectionList select_all_matches(const Buffer& buffer, const Selection& selection, const Regex& regex)
 {
-    auto sel_end = utf8::next(selection.max());
-    RegexIterator re_it(selection.min(), sel_end, regex);
+    auto sel_end = utf8::next(buffer.iterator_at(selection.max()));
+    RegexIterator re_it(buffer.iterator_at(selection.min()), sel_end, regex);
     RegexIterator re_end;
 
     SelectionList result;
@@ -620,13 +620,12 @@ SelectionList select_all_matches(const Buffer& buffer, const Selection& selectio
 SelectionList split_selection(const Buffer& buffer, const Selection& selection,
                               const Regex& regex)
 {
-    auto sel_end = utf8::next(selection.max());
-    RegexIterator re_it(selection.min(), sel_end, regex,
-                        boost::regex_constants::match_nosubs);
+    auto begin = buffer.iterator_at(selection.min());
+    auto sel_end = utf8::next(buffer.iterator_at(selection.max()));
+    RegexIterator re_it(begin, sel_end, regex, boost::regex_constants::match_nosubs);
     RegexIterator re_end;
 
     SelectionList result;
-    BufferIterator begin = selection.min();
     for (; re_it != re_end; ++re_it)
     {
         BufferIterator end = (*re_it)[0].first;
diff --git a/src/unit_tests.cc b/src/unit_tests.cc
index 77e081d6..789e9c79 100644
--- a/src/unit_tests.cc
+++ b/src/unit_tests.cc
@@ -62,8 +62,8 @@ void test_editor()
         editor.multi_select(std::bind(select_all_matches, _1, _2, Regex{"\\n\\h*"}));
         for (auto& sel : editor.selections())
         {
-            kak_assert(*sel.min() == '\n');
-            editor.buffer().erase(sel.min(), utf8::next(sel.max()));
+            kak_assert(buffer.byte_at(sel.min()) == '\n');
+            erase(buffer, sel);
         }
     }
     editor.undo();
@@ -71,7 +71,7 @@ void test_editor()
     Selection sel{ buffer.iterator_at_line_begin(2_line), buffer.end()-1 };
     editor.select(sel, SelectMode::Replace);
     editor.insert("",InsertMode::Replace);
-    kak_assert(not editor.main_selection().first().is_end());
+    kak_assert(not buffer.is_end(editor.main_selection().first()));
 }
 
 void test_incremental_inserter()
diff --git a/src/window.cc b/src/window.cc
index 6dea573e..dba0a302 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -42,7 +42,7 @@ void Window::display_selection_at(LineCount line)
 {
     if (line >= 0 or line < m_dimensions.line)
     {
-        auto cursor_line = main_selection().last().line();
+        auto cursor_line = main_selection().last().line;
         m_position.line = std::max(0_line, cursor_line - line);
     }
 }
@@ -69,14 +69,12 @@ void Window::update_display_buffer()
         LineCount buffer_line = m_position.line + line;
         if (buffer_line >= buffer().line_count())
             break;
-        BufferIterator line_begin = buffer().iterator_at_line_begin(buffer_line);
-        BufferIterator line_end   = buffer().iterator_at_line_end(buffer_line);
-
-        BufferIterator begin = utf8::advance(line_begin, line_end, (int)m_position.column);
-        BufferIterator end   = utf8::advance(begin,      line_end, (int)m_dimensions.column);
+        BufferCoord limit{buffer_line+1, 0};
+        auto begin = std::min(buffer().char_advance(buffer_line, m_position.column), limit);
+        auto end   = std::min(buffer().char_advance(begin, m_dimensions.column), limit);
 
         lines.push_back(DisplayLine(buffer_line));
-        lines.back().push_back(DisplayAtom(AtomContent(buffer(), begin.coord(), end.coord())));
+        lines.back().push_back(DisplayAtom(AtomContent(buffer(), begin, end)));
     }
 
     m_display_buffer.compute_range();
@@ -112,26 +110,24 @@ static LineCount adapt_view_pos(LineCount line, LineCount offset,
 
 void Window::scroll_to_keep_cursor_visible_ifn()
 {
-    const BufferIterator first = main_selection().first();
-    const BufferIterator last  = main_selection().last();
+    const auto& first = main_selection().first();
+    const auto& last  = main_selection().last();
 
     const LineCount offset = std::min<LineCount>(options()["scrolloff"].get<int>(),
                                                  (m_dimensions.line - 1) / 2);
 
     // scroll lines if needed, try to get as much of the selection visible as possible
-    m_position.line = adapt_view_pos(first.line(), offset, m_position.line,
+    m_position.line = adapt_view_pos(first.line, offset, m_position.line,
                                      m_dimensions.line, buffer().line_count());
-    m_position.line = adapt_view_pos(last.line(),  offset, m_position.line,
+    m_position.line = adapt_view_pos(last.line,  offset, m_position.line,
                                      m_dimensions.line, buffer().line_count());
 
     // highlight only the line containing the cursor
     DisplayBuffer display_buffer;
     DisplayBuffer::LineList& lines = display_buffer.lines();
-    lines.push_back(DisplayLine(last.line()));
+    lines.push_back(DisplayLine(last.line));
 
-    BufferIterator line_begin = buffer().iterator_at_line_begin(last);
-    BufferIterator line_end   = buffer().iterator_at_line_end(last);
-    lines.back().push_back(DisplayAtom(AtomContent(buffer(), line_begin.coord(), line_end.coord())));
+    lines.back().push_back(DisplayAtom(AtomContent(buffer(), last.line, last.line+1)));
 
     display_buffer.compute_range();
     m_highlighters(*this, display_buffer);
@@ -145,21 +141,21 @@ void Window::scroll_to_keep_cursor_visible_ifn()
     for (auto& atom : lines.back())
     {
         if (atom.content.has_buffer_range() and
-            atom.content.begin() <= last.coord() and atom.content.end() > last.coord())
+            atom.content.begin() <= last and atom.content.end() > last)
         {
             if (atom.content.type() == AtomContent::BufferRange)
-                column += utf8::distance(buffer().iterator_at(atom.content.begin()), last);
+                column += buffer().char_distance(atom.content.begin(), last);
             else
                 column += atom.content.content().char_length();
 
-            CharCount first_col = first.line() == last.line() ?
-                                  utf8::distance(line_begin, first) : 0_char;
+            CharCount first_col = first.line == last.line ?
+                                  buffer().char_distance(last.line, first) : 0_char;
             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 = utf8::distance(line_begin, last);
+            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)
@@ -169,7 +165,7 @@ void Window::scroll_to_keep_cursor_visible_ifn()
         }
         column += atom.content.content().char_length();
     }
-    if (last != buffer().end())
+    if (not buffer().is_end(last))
     {
         // the cursor should always be visible.
         kak_assert(false);