From d7ea3abb65eb87bdfb2b6bbb1dbf3d4f932b9a0b Mon Sep 17 00:00:00 2001
From: Keith Winstein <keithw@mit.edu>
Date: Sat, 22 Jan 2011 15:01:30 -0500
Subject: [PATCH] Implement ED (clear screen)

---
 terminal.cpp    | 40 ++++++++++++++++++++++++----------------
 terminal.hpp    |  3 +++
 terminalcsi.cpp | 36 ++++++++++++++++++++++++++++++++++--
 3 files changed, 61 insertions(+), 18 deletions(-)

diff --git a/terminal.cpp b/terminal.cpp
index d477449..7bf7bf8 100644
--- a/terminal.cpp
+++ b/terminal.cpp
@@ -138,27 +138,16 @@ void Emulator::print( Parser::Print *act )
 
     autoscroll();
 
-    this_cell =  &rows[ cursor_row ].cells[ cursor_col ];
-    this_cell->contents.clear();
+    this_cell = &rows[ cursor_row ].cells[ cursor_col ];
+    this_cell->reset();
     this_cell->contents.push_back( act->ch );
-    for ( std::vector<Cell *>::iterator i
-	    = this_cell->overlapped_cells.begin();
-	  i != this_cell->overlapped_cells.end();
-	  i++ ) {
-      **i = Cell();
-    }
-    this_cell->overlapped_cells.clear();
 
     newgrapheme();
 
-    if ( cursor_col < width - 1 ) {
+    if ( (cursor_col < width - 1) && (chwidth == 2) ) {
       Cell *next_cell = &rows[ cursor_row ].cells[ cursor_col + 1 ];
-      if ( chwidth == 2 ) {
-	this_cell->overlapped_cells.push_back( next_cell );
-	next_cell->overlapping_cell = this_cell;
-      } else {
-	next_cell->overlapping_cell = NULL;
-      }
+      this_cell->overlapped_cells.push_back( next_cell );
+      next_cell->overlapping_cell = this_cell;
     }
 
     cursor_col += chwidth;
@@ -232,6 +221,8 @@ void Emulator::CSI_dispatch( Parser::CSI_Dispatch *act )
 
   if ( dispatch_chars == "K" ) {
     CSI_EL();
+  } else if ( dispatch_chars == "J" ) {
+    CSI_ED();
   } else if ( (dispatch_chars == "A")
 	      || (dispatch_chars == "B")
 	      || (dispatch_chars == "C")
@@ -288,3 +279,20 @@ int Emulator::getparam( size_t N, int defaultval )
 
   return ret;
 }
+
+void Cell::reset( void )
+{
+  if ( overlapping_cell ) {
+    assert( overlapped_cells.size() == 0 );
+    contents.clear();
+  } else {
+    contents.clear();
+    for ( std::vector<Cell *>::iterator i = overlapped_cells.begin();
+	  i != overlapped_cells.end();
+	  i++ ) {
+      (*i)->overlapping_cell = NULL;
+      (*i)->reset();
+    }
+    overlapped_cells.clear();
+  }
+}
diff --git a/terminal.hpp b/terminal.hpp
index 4cacd7c..663f5ff 100644
--- a/terminal.hpp
+++ b/terminal.hpp
@@ -19,6 +19,8 @@ namespace Terminal {
   
     Cell( const Cell & );
     Cell & operator=( const Cell & );
+
+    void reset( void );
 };
 
   class Row {
@@ -66,6 +68,7 @@ namespace Terminal {
 
     /* CSI methods */
     void CSI_EL( void );
+    void CSI_ED( void );
     void CSI_cursormove( void );
 
   public:
diff --git a/terminalcsi.cpp b/terminalcsi.cpp
index 23cfe20..de0633d 100644
--- a/terminalcsi.cpp
+++ b/terminalcsi.cpp
@@ -8,13 +8,45 @@ void Emulator::CSI_EL( void )
 {
   if ( params == "1" ) { /* start of screen to active position, inclusive */
     for ( int x = 0; x <= cursor_col; x++ ) {
-      rows[ cursor_row ].cells[ x ].contents.clear();
+      if ( x < width ) {
+	rows[ cursor_row ].cells[ x ].reset();
+      }
     }
   } else if ( params == "2" ) { /* all of line */
     rows[ cursor_row ] = Row( width );
   } else { /* active position to end of line, inclusive */
     for ( int x = cursor_col; x < width; x++ ) {
-      rows[ cursor_row ].cells[ x ].contents.clear();
+      rows[ cursor_row ].cells[ x ].reset();
+    }
+  }
+}
+
+void Emulator::CSI_ED( void ) {
+  if ( params == "1" ) { /* start of screen to active position, inclusive */
+    for ( int y = 0; y < cursor_row; y++ ) {
+      for ( int x = 0; x < width; x++ ) {
+	rows[ y ].cells[ x ].reset();
+      }
+    }
+    for ( int x = 0; x <= cursor_col; x++ ) {
+      if ( x < width ) {
+	rows[ cursor_row ].cells[ x ].reset();
+      }
+    }
+  } else if ( params == "2" ) { /* entire screen */
+    for ( int y = 0; y < height; y++ ) {
+      for ( int x = 0; x < width; x++ ) {
+	rows[ y ].cells[ x ].reset();
+      }
+    }
+  } else { /* active position to end of screen, inclusive */
+    for ( int x = cursor_col; x < width; x++ ) {
+      rows[ cursor_row ].cells[ x ].reset();
+    }
+    for ( int y = cursor_row + 1; y < height; y++ ) {
+      for ( int x = 0; x < width; x++ ) {
+	rows[ y ].cells[ x ].reset();
+      }
     }
   }
 }