Implemented \ESC[?47h and \ESC[?47l (use alternative/normal screen

buffer). These are the sequences our /etc/termcap uses (local less and
vim use the alternative screen buffer now). The ones already implemented
are used e.g. by the termcap of my Linux installation. A bit weird all
those different termcap files, some even with the same version
number.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26031 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/apps/terminal/TermParse.cpp

@@ -1093,9 +1093,13 @@ TermParse::_DecPrivateModeSet(int value)
 			// Not supported yet.
 			break;
 		case 25:
-			// Show Cursor
+			// Show Cursor.
 			// Not supported yet.
 			break;
+		case 47:
+			// Use Alternate Screen Buffer.
+			fBuffer->UseAlternateScreenBuffer(false);
+			break;
 		case 1034:
 			// Interpret "meta" key, sets eighth bit.
 			// Not supported yet.
@@ -1104,7 +1108,7 @@ TermParse::_DecPrivateModeSet(int value)
 			// Save cursor as in DECSC and use Alternate Screen Buffer, clearing
 			// it first.
 			fBuffer->SaveCursor();
-			fBuffer->UseAlternateScreenBuffer();
+			fBuffer->UseAlternateScreenBuffer(true);
 			break;
 	}
 }
@@ -1138,14 +1142,18 @@ TermParse::_DecPrivateModeReset(int value)
 			// Hide Cursor
 			// Not supported yet.
 			break;
+		case 47:
+			// Use Normal Screen Buffer.
+			fBuffer->UseNormalScreenBuffer();
+			break;
 		case 1034:
 			// Don’t interpret "meta" key.
 			// Not supported yet.
 			break;
 		case 1049:
 			// Use Normal Screen Buffer and restore cursor as in DECRC.
-			fBuffer->RestoreCursor();
 			fBuffer->UseNormalScreenBuffer();
+			fBuffer->RestoreCursor();
 			break;
 	}
 }

src/apps/terminal/TerminalBuffer.cpp

@@ -176,13 +176,16 @@ TerminalBuffer::ResizeTo(int32 width, int32 height, int32 historyCapacity)
 
 
 void
-TerminalBuffer::UseAlternateScreenBuffer()
+TerminalBuffer::UseAlternateScreenBuffer(bool clear)
 {
 	if (fAlternateScreenActive || fAlternateScreen == NULL)
 		return;
 
 	_SwitchScreenBuffer();
-	Clear(false);
+
+	if (clear)
+		Clear(false);
+
 	_InvalidateAll();
 }
 

src/apps/terminal/TerminalBuffer.h

@@ -32,7 +32,7 @@ public:
 	virtual	status_t			ResizeTo(int32 width, int32 height,
 									int32 historyCapacity);
 
-			void				UseAlternateScreenBuffer();
+			void				UseAlternateScreenBuffer(bool clear);
 			void				UseNormalScreenBuffer();
 
 protected: