Make 'show_line()' do proper TAB handling

The TAB handling got broken by commit cee00b0efb86 ("Show UTF-8 input as
UTF-8 output") when it stopped doing things one byte at a time.

I'm sure the other special character cases are broken too.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 4 deletions

diff --git a/display.c b/display.c
index 676514d..326dc9e 100644
--- a/display.c
+++ b/display.c
@@ -442,13 +442,26 @@ static void show_line(struct line *lp)
 
 	while (i < len) {
 		unicode_t c;
+		int n;
 
-		i += utf8_to_unicode(lp->l_text, i, len, &c);
-		if (vtcol >= term.t_ncol)
+		if (vtcol >= term.t_ncol) {
 			vp->v_text[term.t_ncol - 1] = '$';
-		else if (vtcol >= 0)
-			vp->v_text[vtcol] = c;
+			return;
+		}
+		n = utf8_to_unicode(lp->l_text, i, len, &c);
+		/*
+		 * Change tabs into spaces, and don't increment
+		 * the text source until we hit tabmask
+		 */
 		++vtcol;
+		if (c == '\t') {
+			c = ' ';
+			if (vtcol & tabmask)
+				n = 0;
+		}
+		if (vtcol > 0)
+			vp->v_text[vtcol-1] = c;
+		i += n;
 	}
 }