Resolve some regressions related to tabs and linewrap handling.

It turns out I was looking too much at mimicing xterm, that I didn't
take the differences of cons25 into account. There are some differences
between xterm and cons25 that are important. Create a new #define called
TEKEN_CONS25 that can be toggled to switch between cons25 and xterm
mode.

- Don't forget to redraw the cursor after processing a forward/backward
  tabulation.

- Implement cons25-style (WYSE?) autowrapping. This form of autowrapping
  isn't that nice. It wraps the cursor when printing something on column
  80. xterm wraps when printing the first character that doesn't fit.

- In cons25, a \t shouldn't overwrite previous contents, while xterm
  does.

Reported by:	Garrett Cooper <yanefbsd gmail com>

sys/dev/syscons/teken/teken.c

@@ -68,7 +68,11 @@ teken_wcwidth(teken_char_t c)
 #define	TS_INSERT	0x02	/* Insert mode. */
 #define	TS_AUTOWRAP	0x04	/* Autowrap. */
 #define	TS_ORIGIN	0x08	/* Origin mode. */
+#ifdef TEKEN_CONS25
+#define	TS_WRAPPED	0x00	/* Simple line wrapping. */
+#else /* !TEKEN_CONS25 */
 #define	TS_WRAPPED	0x10	/* Next character should be printed on col 0. */
+#endif /* TEKEN_CONS25 */
 
 /* Character that blanks a cell. */
 #define	BLANK	' '

sys/dev/syscons/teken/teken.h

@@ -43,6 +43,8 @@
  */
 #define	TEKEN_UTF8
 #endif
+/* Emulate cons25-like behaviour. */
+#define	TEKEN_CONS25
 
 #ifdef TEKEN_UTF8
 typedef uint32_t teken_char_t;

sys/dev/syscons/teken/teken_demo.c

@@ -70,7 +70,7 @@ struct pixel {
 };
 
 #define NCOLS	80
-#define NROWS	24
+#define NROWS	25
 struct pixel buffer[NCOLS][NROWS];
 
 static int ptfd;
@@ -279,7 +279,7 @@ main(int argc __unused, char *argv[] __unused)
 		perror("forkpty");
 		exit(1);
 	case 0:
-		setenv("TERM", "xterm-color", 1);
+		setenv("TERM", "cons25", 1);
 		setenv("LC_CTYPE", "UTF-8", 0);
 		execlp("zsh", "-zsh", NULL);
 		execlp("bash", "-bash", NULL);

sys/dev/syscons/teken/teken_subr.h

@@ -250,6 +250,8 @@ teken_subr_cursor_backward_tabulation(teken_t *t, unsigned int ntabs)
 		if (teken_tab_isset(t, t->t_cursor.tp_col))
 			ntabs--;
 	} while (ntabs > 0);
+
+	teken_funcs_cursor(t);
 }
 
 static void
@@ -291,6 +293,8 @@ teken_subr_cursor_forward_tabulation(teken_t *t, unsigned int ntabs)
 		if (teken_tab_isset(t, t->t_cursor.tp_col))
 			ntabs--;
 	} while (ntabs > 0);
+
+	teken_funcs_cursor(t);
 }
 
 static void
@@ -527,6 +531,10 @@ teken_subr_horizontal_position_absolute(teken_t *t, unsigned int col)
 static void
 teken_subr_horizontal_tab(teken_t *t)
 {
+#ifdef TEKEN_CONS25
+
+	teken_subr_cursor_forward_tabulation(t, 1);
+#else /* !TEKEN_CONS25 */
 	teken_rect_t tr;
 
 	tr.tr_begin = t->t_cursor;
@@ -537,6 +545,7 @@ teken_subr_horizontal_tab(teken_t *t)
 	/* Blank region that we skipped. */
 	if (tr.tr_end.tp_col > tr.tr_begin.tp_col)
 		teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
+#endif /* TEKEN_CONS25 */
 }
 
 static void
@@ -708,6 +717,22 @@ teken_subr_regular_character(teken_t *t, teken_char_t c)
 	if (width <= 0)
 		return;
 
+#ifdef TEKEN_CONS25
+	teken_subr_do_putchar(t, &t->t_cursor, c, width);
+	t->t_cursor.tp_col += width;
+
+	if (t->t_cursor.tp_col >= t->t_winsize.tp_col) {
+		if (t->t_cursor.tp_row == t->t_scrollreg.ts_end - 1) {
+			/* Perform scrolling. */
+			teken_subr_do_scroll(t, 1);
+		} else {
+			/* No scrolling needed. */
+			if (t->t_cursor.tp_row < t->t_winsize.tp_row - 1)
+				t->t_cursor.tp_row++;
+		}
+		t->t_cursor.tp_col = 0;
+	}
+#else /* !TEKEN_CONS25 */
 	if (t->t_cursor.tp_col == t->t_winsize.tp_col - 1 &&
 	    (t->t_stateflags & (TS_WRAPPED|TS_AUTOWRAP)) ==
 	    (TS_WRAPPED|TS_AUTOWRAP)) {
@@ -752,6 +777,7 @@ teken_subr_regular_character(teken_t *t, teken_char_t c)
 			t->t_stateflags &= ~TS_WRAPPED;
 		}
 	}
+#endif /* TEKEN_CONS25 */
 
 	teken_funcs_cursor(t);
 }