Reduce use of malloc()

stmclient.cpp

@@ -128,9 +128,9 @@ void STMClient::output_new_frame( void )
   overlays.apply( new_state );
 
   /* calculate minimal difference from where we are */
-  string diff = Terminal::Display::new_frame( !repaint_requested,
-					      *local_framebuffer,
-					      new_state );
+  const string diff( Terminal::Display::new_frame( !repaint_requested,
+						   *local_framebuffer,
+						   new_state ) );
   swrite( STDOUT_FILENO, diff.data(), diff.size() );
   *local_framebuffer = new_state;  
 

terminaldisplay.cpp

@@ -170,7 +170,7 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
   /* have renditions changed? */
   if ( (!initialized)
        || (f.ds.get_renditions().sgr() != frame.current_rendition_string) ) {
-    frame.append( f.ds.get_renditions().sgr() );
+    frame.appendstring( f.ds.get_renditions().sgr() );
     frame.current_rendition_string = f.ds.get_renditions().sgr();
   }
 
@@ -197,7 +197,7 @@ void Display::put_cell( bool initialized, FrameState &frame, const Framebuffer &
 
   if ( frame.current_rendition_string != rendition_str ) {
     /* print renditions */
-    frame.append( rendition_str );
+    frame.appendstring( rendition_str );
     frame.current_rendition_string = rendition_str;
   }
 

terminaldisplay.hpp

@@ -15,8 +15,16 @@ namespace Terminal {
 
     Framebuffer last_frame;
 
-    FrameState( const Framebuffer &s_last ) : x(0), y(0), str(), cursor_x(0), cursor_y(0), current_rendition_string(), last_frame( s_last ) {}
-    void append( std::string s ) { str.append( s ); }
+    FrameState( const Framebuffer &s_last )
+      : x(0), y(0),
+	str(), cursor_x(0), cursor_y(0), current_rendition_string(),
+	last_frame( s_last )
+    {
+      str.reserve( 1024 );
+    }
+
+    void append( const char * s ) { str.append( s ); }
+    void appendstring( const std::string s ) { str.append( s ); }
 
     void append_silent_move( int y, int x );
   };