DisplayBuffer: do not store content in atom, begin and end are sufficient

src/display_buffer.cc

@@ -9,17 +9,15 @@ DisplayBuffer::DisplayBuffer()
 {
 }
 
-DisplayBuffer::iterator DisplayBuffer::split(iterator atom, size_t pos_in_atom)
+DisplayBuffer::iterator DisplayBuffer::split(iterator atom, const BufferIterator& pos)
 {
     assert(atom < end());
-    assert(pos_in_atom > 0);
-    assert(pos_in_atom < atom->content.length());
-    DisplayAtom new_atom(atom->begin, atom->begin + pos_in_atom,
-                         atom->content.substr(0, pos_in_atom),
+    assert(pos > atom->begin);
+    assert(pos < atom->end);
+    DisplayAtom new_atom(atom->begin, pos,
                          atom->fg_color, atom->bg_color, atom->attribute);
 
-    atom->begin = atom->begin + pos_in_atom;
-    atom->content = atom->content.substr(pos_in_atom);
+    atom->begin = pos;
     return insert(atom, std::move(new_atom));
 }
 

src/display_buffer.hh

@@ -35,7 +35,6 @@ enum class Color
 
 struct DisplayAtom
 {
-    std::string    content;
     BufferIterator begin;
     BufferIterator end;
     Color          fg_color;
@@ -43,12 +42,10 @@ struct DisplayAtom
     Attribute      attribute;
 
     DisplayAtom(BufferIterator begin, BufferIterator end,
-                const std::string& content,
                 Color fg_color = Color::Default,
                 Color bg_color = Color::Default,
                 Attribute attribute = Attributes::Normal)
-        : content(content),
-          begin(begin),
+        : begin(begin),
           end(end),
           fg_color(fg_color),
           bg_color(bg_color),
@@ -68,7 +65,7 @@ public:
     void clear() { m_atoms.clear(); }
     void append(const DisplayAtom& atom) { m_atoms.push_back(atom); }
     iterator insert(iterator where, const DisplayAtom& atom) { return m_atoms.insert(where, atom); }
-    iterator split(iterator atom, size_t pos_in_atom);
+    iterator split(iterator atom, const BufferIterator& pos);
 
     iterator begin() { return m_atoms.begin(); }
     iterator end()   { return m_atoms.end(); }

src/filters.cc

@@ -9,16 +9,16 @@ void colorize_regex(DisplayBuffer& display_buffer,
     for (auto atom_it = display_buffer.begin();
          atom_it != display_buffer.end(); ++atom_it)
     {
-        boost::smatch matches;
-        if (boost::regex_search(atom_it->content, matches, ex, boost::match_nosubs))
+        boost::match_results<BufferIterator> matches;
+        if (boost::regex_search(atom_it->begin, atom_it->end, matches, ex, boost::match_nosubs))
         {
-            size_t pos = matches.begin()->first - atom_it->content.begin();
-            if (pos != 0)
-                atom_it = display_buffer.split(atom_it, pos) + 1;
+            const BufferIterator& begin = matches.begin()->first;
+            if (begin != atom_it->begin)
+                atom_it = display_buffer.split(atom_it, begin) + 1;
 
-            pos = matches.begin()->second - matches.begin()->first;
-            if (pos != atom_it->content.length())
-                atom_it = display_buffer.split(atom_it, pos);
+            const BufferIterator& end = matches.begin()->second;
+            if (end != atom_it->end)
+                atom_it = display_buffer.split(atom_it, end);
 
             atom_it->fg_color = color;
         }

src/main.cc

@@ -81,7 +81,7 @@ void draw_window(Window& window)
     WindowCoord position;
     for (const DisplayAtom& atom : window.display_buffer())
     {
-        const std::string& content = atom.content;
+        const std::string content = window.buffer().string(atom.begin, atom.end);
 
         set_attribute(A_UNDERLINE, atom.attribute & Underline);
         set_attribute(A_REVERSE, atom.attribute & Reverse);

src/window.cc

@@ -62,8 +62,7 @@ public:
             // [###------]
             if (atom.begin >= sel.begin() and atom.begin < sel.end() and atom.end > sel.end())
             {
-                size_t length = sel.end() - atom.begin;
-                atom_it = display_buffer.split(atom_it, length);
+                atom_it = display_buffer.split(atom_it, sel.end());
                 atom_it->attribute |= Attributes::Underline;
                 ++atom_it;
                 ++sel_it;
@@ -71,10 +70,8 @@ public:
             // [---###---]
             else if (atom.begin < sel.begin() and atom.end > sel.end())
             {
-                size_t prefix_length = sel.begin() - atom.begin;
-                atom_it = display_buffer.split(atom_it, prefix_length);
-                size_t sel_length = sel.end() - sel.begin();
-                atom_it = display_buffer.split(atom_it + 1, sel_length);
+                atom_it = display_buffer.split(atom_it, sel.begin());
+                atom_it = display_buffer.split(atom_it + 1, sel.end());
                 atom_it->attribute |= Attributes::Underline;
                 ++atom_it;
                 ++sel_it;
@@ -82,8 +79,7 @@ public:
             // [------###]
             else if (atom.begin < sel.begin() and atom.end > sel.begin())
             {
-                size_t length = sel.begin() - atom.begin;
-                atom_it = display_buffer.split(atom_it, length) + 1;
+                atom_it = display_buffer.split(atom_it, sel.begin()) + 1;
                 atom_it->attribute |= Attributes::Underline;
                 ++atom_it;
             }
@@ -289,7 +285,10 @@ void Window::update_display_buffer()
     BufferIterator begin = m_buffer.iterator_at(m_position);
     BufferIterator end = m_buffer.iterator_at(m_position +
                                               BufferCoord(m_dimensions.line, m_dimensions.column+1));
-    m_display_buffer.append(DisplayAtom(begin, end, m_buffer.string(begin, end)));
+    if (begin == end)
+        return;
+
+    m_display_buffer.append(DisplayAtom(begin, end));
 
     for (auto& filter : m_filters)
     {