Add HTS sequence

This sequence adds a new tab stop in the current horizontal position. This
means that tputtab must be look for the next tab stop in the tabs array
instead of using a hard coded value offset. Also, CHT sequence XXX message
is removed because it is not a vt10x sequence (as far as I know it is a
vt50x sequence), and it is not implemented by linux virtual terminal neither
by xterm.

Signed-off-by: Roberto E. Vargas Caballero <k0ga@shike2.com>
---
 st.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

st.c

@@ -1214,7 +1214,6 @@ csihandle(void) {
 		DEFAULT(escseq.arg[1], 1);
 		tmoveto(escseq.arg[1]-1, escseq.arg[0]-1);
 		break;
-	/* XXX: (CSI n I) CHT -- Cursor Forward Tabulation <n> tab stops */
 	case 'J': /* ED -- Clear screen */
 		sel.bx = -1;
 		switch(escseq.arg[0]) {
@@ -1429,8 +1428,11 @@ csireset(void) {
 
 void
 tputtab(void) {
-	int space = TAB - term.c.x % TAB;
+	unsigned x;
-	tmoveto(term.c.x + space, term.c.y);
+
+	for (x = term.c.x + 1; x < term.col && !term.tabs[x]; ++x)
+		/* nothing */ ;
+	tmoveto(x, term.c.y);
 }
 
 void
@@ -1491,6 +1493,10 @@ tputc(char *c) {
 				tnewline(1); /* always go to first col */
 				term.esc = 0;
 				break;
+			case 'H': /* HTS -- Horizontal tab stop */
+				term.tabs[term.c.x] = 1;
+				term.esc = 0;
+				break;
 			case 'M': /* RI -- Reverse index */
 				if(term.c.y == term.top)
 					tscrolldown(term.top, 1);