Add support for DECSC/DECRC

This allows for a way to save/restore the cursor position when
DECLRMM is enabled.

Saves to the same variables as SCOSC/SCORC.

src/conio/cterm.adoc

@@ -92,6 +92,16 @@ Control codes are in the following format: +
 `ESC {'0'` to `'~'}`
 Legal combinations which are not handled are silently dropped.
 
+=== `ESC 7` Save Cursor (`DECSC`)
+Saves the current cursor position same as `CSI s`
+
+SOURCE: <<VT102>>
+
+=== `ESC 8` Restore Cursor (`DECRC`)
+Restores the current cursor position same as `CSI u`
+
+SOURCE: <<VT102>>
+
 === `ESC E` Next Line (`NEL`)
 Moves to the line home position of the next line.
 (Same as `CR` `LF`)

src/conio/cterm.c

@@ -4277,6 +4277,19 @@ static void do_ansi(struct cterminal *cterm, char *retbuf, size_t retsize, int *
 					}
 				}
 				break;
+			case '7':	// Save cursor position
+				CURR_XY(&cterm->save_xpos, &cterm->save_ypos);
+				break;
+			case '8':	// Restore cursor positi9on
+				if(cterm->save_ypos>0 && cterm->save_ypos<=cterm->height
+						&& cterm->save_xpos>0 && cterm->save_xpos<=cterm->width) {
+					// TODO: What to do about the window when position is restored...
+					//       Absolute position stored?  Relative?
+					if(cterm->save_ypos < CURR_MINY || cterm->save_ypos > CURR_MAXY || cterm->save_xpos < CURR_MINX || cterm->save_xpos > CURR_MAXX)
+						break;
+					gotoxy(cterm->save_xpos, cterm->save_ypos);
+				}
+				break;
 			case 'E':	// Next Line
 				clear_lcf(cterm);
 				adjust_currpos(cterm, INT_MIN, 1, 1);
@@ -4724,7 +4737,7 @@ cterm_reset(struct cterminal *cterm)
 
 struct cterminal* cterm_init(int height, int width, int xpos, int ypos, int backlines, int backcols, struct vmem_cell *scrollback, int emulation)
 {
-	char	*revision="$Revision: 1.320 $";
+	char	*revision="$Revision: 1.321 $";
 	char *in;
 	char	*out;
 	struct cterminal *cterm;

src/sbbs3/ansi_terminal.cpp

@@ -7,7 +7,8 @@
  * 
  * Note that SCOSC and SCORC are not standard and conflict with the DEC
  * left/right margin settings (DECLRMM).  If this becomes an issue, they
- * can be emulated via cusros position query.
+ * can be emulated via cusros position query.  There's also the VT100
+ * DECSC/DECRC (ESC8/ESC8) that may work when DECLRMM works.
  * 
  * CUU   - ESC[A Cursor Up (With count)
  * CUD   - ESC[B Cursor Down (With count)

xtrn/termtest/termtest.js

@@ -1073,6 +1073,14 @@ var tests = [
 		console.write("\x1b[u");
 		return check_xy(2,2);
 	}},
+	{'name':'DECSC', 'func':function() {
+		console.gotoxy(2,2);
+		console.write("\x1b7");
+		console.gotoxy(1,1);
+		console.write('     ');
+		console.write("\x1b8");
+		return check_xy(2,2);
+	}},
 	{'name':'CT24BC', 'func':function() {
 		if (!interactive)
 			return null;
@@ -1131,6 +1139,14 @@ var tests = [
 		console.write("\x1b[u");
 		return check_xy(2,2);
 	}},
+	{'name':'DECRC', 'func':function() {
+		console.gotoxy(2,2);
+		console.write("\x1b7");
+		console.gotoxy(1,1);
+		console.write('     ');
+		console.write("\x1b8");
+		return check_xy(2,2);
+	}},
 	{'name':'DECTABSR', 'func':function() {
 		console.write("\x1b[2$w");
 		var seq = read_ansi_string(500);