Describe Cell width as a narrow/wide boolean.

A character cell can only be either narrow or wide.  It's more
convenient to represent that as an int containing 1 or 2, but slightly
more correct to represent it as a "boolean" single-bit integer.

src/terminal/terminal.cc

@@ -106,7 +106,7 @@ void Emulator::print( const Parser::Print *act )
 
     fb.reset_cell( this_cell );
     this_cell->append( ch );
-    this_cell->set_width( chwidth );
+    this_cell->set_wide( chwidth == 2 ); /* chwidth had better be 1 or 2 here */
     fb.apply_renditions_to_cell( this_cell );
 
     if ( chwidth == 2 ) { /* erase overlapped cell */
@@ -131,7 +131,7 @@ void Emulator::print( const Parser::Print *act )
 	   base character [e.g. start of line], if the
 	   combining character has been cleared with
 	   a sequence like ED ("J") or EL ("K") */
-	assert( combining_cell->get_width() == 1 );
+	assert( !combining_cell->get_wide() );
 	combining_cell->set_fallback( true );
 	fb.ds.move_col( 1, true, true );
       }

src/terminal/terminalframebuffer.cc

@@ -41,14 +41,14 @@ using namespace Terminal;
 Cell::Cell( color_type background_color )
   : contents(),
     renditions( background_color ),
-    width( 1 ),
+    wide( false ),
     fallback( false ),
     wrap( false )
 {}
 Cell::Cell() /* default constructor required by C++11 STL */
   : contents(),
     renditions( 0 ),
-    width( 1 ),
+    wide( false ),
     fallback( false ),
     wrap( false )
 {
@@ -59,7 +59,7 @@ void Cell::reset( color_type background_color )
 {
   contents.clear();
   renditions = Renditions( background_color );
-  width = 1;
+  wide = false;
   fallback = false;
   wrap = false;
 }
@@ -642,10 +642,10 @@ bool Cell::compare( const Cell &other ) const
 	     fallback, other.fallback );
   }
 
-  if ( width != other.width ) {
+  if ( wide != other.wide ) {
     ret = true;
     fprintf( stderr, "width: %d vs. %d\n",
-	     width, other.width );
+	     wide, other.wide );
   }
 
   if ( !(renditions == other.renditions) ) {

src/terminal/terminalframebuffer.h

@@ -89,7 +89,7 @@ namespace Terminal {
     typedef std::string content_type; /* can be std::string, std::vector<uint8_t>, or __gnu_cxx::__vstring */
     content_type contents;
     Renditions renditions;
-    unsigned int width : 2;
+    unsigned int wide : 1; /* 0 = narrow, 1 = wide */
     unsigned int fallback : 1; /* first character is combining character */
     unsigned int wrap : 1;
 
@@ -103,7 +103,7 @@ namespace Terminal {
     {
       return ( (contents == x.contents)
 	       && (fallback == x.fallback)
-	       && (width == x.width)
+	       && (wide == x.wide)
 	       && (renditions == x.renditions)
 	       && (wrap == x.wrap) );
     }
@@ -190,8 +190,9 @@ namespace Terminal {
     const Renditions& get_renditions( void ) const { return renditions; }
     Renditions& get_renditions( void ) { return renditions; }
     void set_renditions( const Renditions& r ) { renditions = r; }
-    unsigned int get_width( void ) const { return width; }
-    void set_width( unsigned int w ) { width = w; }
+    bool get_wide( void ) const { return wide; }
+    void set_wide( bool w ) { wide = w; }
+    unsigned int get_width( void ) const { return wide + 1; }
     bool get_fallback( void ) const { return fallback; }
     void set_fallback( bool f ) { fallback = f; }
     bool get_wrap( void ) const { return wrap; }