Refactoring FVTerm::updateTerminalLine

ChangeLog

@@ -1,3 +1,6 @@
+2017-11-30  Markus Gans  <guru.mail@muenster.de>
+	* Refactoring FVTerm::updateTerminalLine
+
 2017-11-26  Markus Gans  <guru.mail@muenster.de>
 	* Better code readability by splitting FOptiMove::moveCursor 
 	  into sub-functions

include/final/fvterm.h

@@ -343,9 +343,16 @@ class FVTerm : public FTerm
     term_area*    vwin;                    // virtual window
 
   private:
-    // Typedef
+    // Typedef and Enumeration
     typedef FTermcap::tcap_map termcap_map;
 
+    enum exit_state
+    {
+      not_used,
+      used,
+      line_completely_printed
+    };
+
     // Constants
     static const uInt TERMINAL_OUTPUT_BUFFER_SIZE = 32768;
     // Buffer size for character output on the terminal
@@ -363,6 +370,14 @@ class FVTerm : public FTerm
     void                    init();
     void                    finish();
     static bool             clearTerm (int = ' ');
+    static bool             canClearToEOL (uInt, uInt);
+    static bool             canClearLeadingWS (uInt&, uInt);
+    static bool             canClearTailingWS (uInt&, uInt);
+    static bool             skipUnchangedCharacters (uInt&, uInt, uInt);
+    static void             printRange (uInt, uInt, uInt, bool);
+    static exit_state       eraseCharacters (uInt&, uInt, uInt, bool);
+    static exit_state       repeatCharacter (uInt&, uInt, uInt);
+    static void             cursorWrap();
     static void             updateTerminalLine (uInt);
     static bool             updateTerminalCursor();
     static bool             isInsideTerminal (int, int);

src/fvterm.cpp

@@ -2244,28 +2244,16 @@ bool FVTerm::clearTerm (int fillchar)
 }
 
 //----------------------------------------------------------------------
-void FVTerm::updateTerminalLine (uInt y)
+bool FVTerm::canClearToEOL (uInt xmin, uInt y)
 {
-  // Updates pending changes from line y to the terminal
+  // Is the line from xmin to the end of the line blank?
-  term_area* vt = vterm;
+  // => clear to end of line
-  uInt& xmin = vt->changes[y].xmin;
-  uInt& xmax = vt->changes[y].xmax;
-  int term_width = vt->width - 1;
-  int term_height = vt->height - 1;
 
-  if ( xmin <= xmax )
+  term_area*& vt = vterm;
-  {
+  bool&  ut = FTermcap::background_color_erase;
-    bool is_eol_clean = false;
-    bool draw_leading_ws = false;
-    bool draw_tailing_ws = false;
   char*& ce = TCAP(fc::t_clr_eol);
-    char*& cb = TCAP(fc::t_clr_bol);
-    bool ut = FTermcap::background_color_erase;
-    char_data* first_char = &vt->text[y * uInt(vt->width)];
-    char_data* last_char  = &vt->text[(y + 1) * uInt(vt->width) - 1];
   char_data* min_char = &vt->text[y * uInt(vt->width) + xmin];
 
-    // Is the line from xmin to the end of the line blank?
   if ( ce && min_char->code == ' ' )
   {
     uInt beginning_whitespace = 1;
@@ -2284,12 +2272,23 @@ void FVTerm::updateTerminalLine (uInt y)
     if ( beginning_whitespace == uInt(vt->width) - xmin
       && (ut || normal)
       && clr_eol_length < int(beginning_whitespace) )
-        is_eol_clean = true;
+      return true;
   }
 
-    if ( ! is_eol_clean )
+  return false;
+}
+
+//----------------------------------------------------------------------
+bool FVTerm::canClearLeadingWS (uInt& xmin, uInt y)
 {
-      // leading whitespace
+  // Line has leading whitespace
+  // => clear from xmin to beginning of line
+
+  term_area*& vt = vterm;
+  bool&  ut = FTermcap::background_color_erase;
+  char*& cb = TCAP(fc::t_clr_bol);
+  char_data* first_char = &vt->text[y * uInt(vt->width)];
+
   if ( cb && first_char->code == ' ' )
   {
     uInt leading_whitespace = 1;
@@ -2309,12 +2308,25 @@ void FVTerm::updateTerminalLine (uInt y)
       && (ut || normal)
       && clr_bol_length < int(leading_whitespace) )
     {
-          draw_leading_ws = true;
       xmin = leading_whitespace - 1;
+      return true;
     }
   }
 
-      // tailing whitespace
+  return false;
+}
+
+//----------------------------------------------------------------------
+bool FVTerm::canClearTailingWS (uInt& xmax, uInt y)
+{
+  // Line has tailing whitespace
+  // => clear from xmax to end of line
+
+  term_area*& vt = vterm;
+  bool&  ut = FTermcap::background_color_erase;
+  char*& ce = TCAP(fc::t_clr_eol);
+  char_data* last_char = &vt->text[(y + 1) * uInt(vt->width) - 1];
+
   if ( ce && last_char->code == ' ' )
   {
     uInt tailing_whitespace = 1;
@@ -2334,38 +2346,23 @@ void FVTerm::updateTerminalLine (uInt y)
       && (ut || normal)
       && clr_bol_length < int(tailing_whitespace) )
     {
-          draw_tailing_ws = true;
       xmax = uInt(vt->width) - tailing_whitespace;
-        }
+      return true;
     }
   }
 
-    setTermXY (int(xmin), int(y));
+  return false;
-
-    if ( is_eol_clean )
-    {
-      appendAttributes (min_char);
-      appendOutputBuffer (ce);
-      markAsPrinted (xmin, uInt(vt->width - 1), y);
-    }
-    else
-    {
-      if ( draw_leading_ws )
-      {
-        appendAttributes (first_char);
-        appendOutputBuffer (cb);
-        markAsPrinted (0, xmin, y);
 }
 
-      for (uInt x = xmin; x <= xmax; x++)
+//----------------------------------------------------------------------
+bool FVTerm::skipUnchangedCharacters(uInt& x, uInt xmax, uInt y)
 {
-        char_data* print_char;
+  // Skip characters without changes if it is faster than redrawing
-        char*& ec = TCAP(fc::t_erase_chars);
+
-        char*& rp = TCAP(fc::t_repeat_char);
+  term_area*& vt = vterm;
-        print_char = &vt->text[y * uInt(vt->width) + x];
+  char_data* print_char = &vt->text[y * uInt(vt->width) + x];
   print_char->attr.bit.printed = true;
 
-        // skip character with no changes
   if ( print_char->attr.bit.no_changes )
   {
     uInt count = 1;
@@ -2384,13 +2381,65 @@ void FVTerm::updateTerminalLine (uInt y)
     {
       setTermXY (int(x + count), int(y));
       x = x + count - 1;
-            continue;
+      return true;
     }
   }
 
-        // Erase a number of characters to draw simple whitespaces
+  return false;
+}
+
+//----------------------------------------------------------------------
+void FVTerm::printRange ( uInt xmin, uInt xmax, uInt y
+                        , bool draw_tailing_ws )
+{
+  for (uInt x = xmin; x <= xmax; x++)
+  {
+    char_data* print_char;
+    term_area*& vt = vterm;
+    char*& ec = TCAP(fc::t_erase_chars);
+    char*& rp = TCAP(fc::t_repeat_char);
+    print_char = &vt->text[y * uInt(vt->width) + x];
+    print_char->attr.bit.printed = true;
+
+    // skip character with no changes
+    if ( skipUnchangedCharacters(x, xmax, y) )
+      continue;
+
+    // Erase character
     if ( ec && print_char->code == ' ' )
     {
+      exit_state erase_state = \
+          eraseCharacters(x, xmax, y, draw_tailing_ws);
+
+      if ( erase_state == line_completely_printed )
+        break;
+    }
+    else if ( rp )  // Repeat one character n-fold
+    {
+      repeatCharacter(x, xmax, y);
+    }
+    else
+    {
+      // General character output
+      appendCharacter (print_char);
+      markAsPrinted (x, y);
+    }
+  }
+}
+//----------------------------------------------------------------------
+FVTerm::exit_state FVTerm::eraseCharacters ( uInt& x, uInt xmax, uInt y
+                                           , bool draw_tailing_ws )
+{
+  // Erase a number of characters to draw simple whitespaces
+
+  term_area*& vt = vterm;
+  bool&  ut = FTermcap::background_color_erase;
+  char*& ec = TCAP(fc::t_erase_chars);
+  char_data* print_char = &vt->text[y * uInt(vt->width) + x];
+
+  if ( ! ec || print_char->code != ' ' )
+    return not_used;
+
   uInt whitespace = 1;
   bool normal = isNormal(print_char);
 
@@ -2422,7 +2471,7 @@ void FVTerm::updateTerminalLine (uInt y)
       if ( x + whitespace - 1 < xmax || draw_tailing_ws )
         setTermXY (int(x + whitespace), int(y));
       else
-                break;
+        return line_completely_printed;
 
       x = x + whitespace - 1;
     }
@@ -2436,9 +2485,22 @@ void FVTerm::updateTerminalLine (uInt y)
 
     markAsPrinted (start_pos, x, y);
   }
+
+  return used;
 }
-        else if ( rp )  // Repeat one character n-fold
+
+//----------------------------------------------------------------------
+FVTerm::exit_state FVTerm::repeatCharacter (uInt& x, uInt xmax, uInt y)
 {
+  // Repeat one character n-fold
+
+  term_area*& vt = vterm;
+  char*& rp = TCAP(fc::t_repeat_char);
+  char_data* print_char = &vt->text[y * uInt(vt->width) + x];
+
+  if ( ! rp )
+    return not_used;
+
   uInt repetitions = 1;
 
   for (uInt i = x + 1; i <= xmax; i++)
@@ -2480,28 +2542,18 @@ void FVTerm::updateTerminalLine (uInt y)
 
     markAsPrinted (start_pos, x, y);
   }
+
+  return used;
 }
-        else  // General character output
+
+//----------------------------------------------------------------------
+void FVTerm::cursorWrap()
 {
-          appendCharacter (print_char);
+  // Wrap the cursor
-          markAsPrinted (x, y);
+  term_area*& vt = vterm;
-        }
+  int term_width = vt->width - 1;
-      }
+  int term_height = vt->height - 1;
 
-      if ( draw_tailing_ws )
-      {
-        appendAttributes (last_char);
-        appendOutputBuffer (ce);
-        markAsPrinted (xmax + 1, uInt(vt->width - 1), y);
-      }
-    }
-
-    // Reset line changes
-    xmin = uInt(vt->width);
-    xmax = 0;
-  }
-
-  // cursor wrap
   if ( term_pos->getX() > term_width )
   {
     if ( term_pos->getY() == term_height )
@@ -2523,6 +2575,72 @@ void FVTerm::updateTerminalLine (uInt y)
   }
 }
 
+//----------------------------------------------------------------------
+void FVTerm::updateTerminalLine (uInt y)
+{
+  // Updates pending changes from line y to the terminal
+
+  term_area*& vt = vterm;
+  uInt& xmin = vt->changes[y].xmin;
+  uInt& xmax = vt->changes[y].xmax;
+
+  if ( xmin <= xmax )
+  {
+    bool draw_leading_ws = false;
+    bool draw_tailing_ws = false;
+    char*& ce = TCAP(fc::t_clr_eol);
+    char*& cb = TCAP(fc::t_clr_bol);
+    char_data* first_char = &vt->text[y * uInt(vt->width)];
+    char_data* last_char  = &vt->text[(y + 1) * uInt(vt->width) - 1];
+    char_data* min_char   = &vt->text[y * uInt(vt->width) + xmin];
+
+    // Clear rest of line
+    bool is_eol_clean = canClearToEOL (xmin, y);
+
+    if ( ! is_eol_clean )
+    {
+      // leading whitespace
+      draw_leading_ws = canClearLeadingWS (xmin, y);
+
+      // tailing whitespace
+      draw_tailing_ws = canClearTailingWS (xmax, y);
+    }
+
+    setTermXY (int(xmin), int(y));
+
+    if ( is_eol_clean )
+    {
+      appendAttributes (min_char);
+      appendOutputBuffer (ce);
+      markAsPrinted (xmin, uInt(vt->width - 1), y);
+    }
+    else
+    {
+      if ( draw_leading_ws )
+      {
+        appendAttributes (first_char);
+        appendOutputBuffer (cb);
+        markAsPrinted (0, xmin, y);
+      }
+
+      printRange (xmin, xmax, y, draw_tailing_ws);
+
+      if ( draw_tailing_ws )
+      {
+        appendAttributes (last_char);
+        appendOutputBuffer (ce);
+        markAsPrinted (xmax + 1, uInt(vt->width - 1), y);
+      }
+    }
+
+    // Reset line changes
+    xmin = uInt(vt->width);
+    xmax = 0;
+  }
+
+  cursorWrap();
+}
+
 //----------------------------------------------------------------------
 bool FVTerm::updateTerminalCursor()
 {