s390/tty3270: split up tty3270_convert_line()

To make the code easier to read, split up tty3270_convertline()
into several subfunctions:

- tty3270_resize_line() to realloc the line if it doesn't have enough
  space left
- tty3270_required_length() to calculate how much space we need
- tty3270_add_attributes() to add the color and highlight attributes
- tty3270_add_reset_attributes() to reset the attributes at the end of
  the line
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

drivers/s390/char/con3270.c

@@ -1101,6 +1101,18 @@ static char tty3270_graphics_translate(struct tty3270 *tp, char ch)
 	}
 }
 
+static struct string *tty3270_resize_line(struct tty3270 *tp, struct string *s, int newlen)
+{
+	struct string *n = tty3270_alloc_string(tp, newlen);
+
+	list_add(&n->list, &s->list);
+	list_del_init(&s->list);
+	if (!list_empty(&s->update))
+		list_del_init(&s->update);
+	free_string(&tp->freemem, s);
+	return n;
+}
+
 /*
  * Insert character into the screen at the current position with the
  * current color and highlight. This function does NOT do cursor movement.
@@ -1128,26 +1140,19 @@ static void tty3270_put_character(struct tty3270 *tp, char ch)
 	cell->attributes = tp->attributes;
 }
 
-/*
- * Convert a tty3270_line to a 3270 data fragment usable for output.
- */
-static void tty3270_convert_line(struct tty3270 *tp, int line_nr)
+static int tty3270_required_length(struct tty3270 *tp, int line_nr)
 {
+	unsigned char f_color, b_color, highlight;
 	struct tty3270_line *line;
 	struct tty3270_cell *cell;
-	struct string *s, *n;
-	unsigned char highlight;
-	unsigned char f_color, b_color;
-	char *cp;
-	int flen, i;
+	int i, flen = 3;		/* Prefix (TO_SBA). */
 
-	/* Determine how long the fragment will be. */
-	flen = 3;		/* Prefix (TO_SBA). */
 	line = tp->screen + line_nr;
 	flen += line->len;
 	highlight = TAX_RESET;
 	f_color = TAC_RESET;
 	b_color = TAC_RESET;
+
 	for (i = 0, cell = line->cells; i < line->len; i++, cell++) {
 		if (cell->attributes.highlight != highlight) {
 			flen += 3;	/* TO_SA to switch highlight. */
@@ -1173,80 +1178,107 @@ static void tty3270_convert_line(struct tty3270 *tp, int line_nr)
 	if (line->len < tp->view.cols)
 		flen += 4;	/* Postfix (TO_RA). */
 
-	/* Find the line in the list. */
-	i = tp->view.rows - 2 - line_nr;
-	list_for_each_entry_reverse(s, &tp->lines, list)
-		if (--i <= 0)
-			break;
-	/*
-	 * Check if the line needs to get reallocated.
-	 */
-	if (s->len != flen) {
-		/* Reallocate string. */
-		n = tty3270_alloc_string(tp, flen);
-		list_add(&n->list, &s->list);
-		list_del_init(&s->list);
-		if (!list_empty(&s->update))
-			list_del_init(&s->update);
-		free_string(&tp->freemem, s);
-		s = n;
+	return flen;
+}
+
+static char *tty3270_add_reset_attributes(struct tty3270 *tp, struct tty3270_line *line,
+					  char *cp, struct tty3270_attribute *attr)
+{
+	if (attr->highlight != TAX_RESET) {
+		*cp++ = TO_SA;
+		*cp++ = TAT_EXTHI;
+		*cp++ = TAX_RESET;
+	}
+	if (attr->f_color != TAC_RESET) {
+		*cp++ = TO_SA;
+		*cp++ = TAT_FGCOLOR;
+		*cp++ = TAC_RESET;
+	}
+	if (attr->b_color != TAC_RESET) {
+		*cp++ = TO_SA;
+		*cp++ = TAT_BGCOLOR;
+		*cp++ = TAC_RESET;
+	}
+	if (line->len < tp->view.cols) {
+		*cp++ = TO_RA;
+		*cp++ = 0;
+		*cp++ = 0;
+		*cp++ = 0;
 	}
+	return cp;
+}
+
+static char *tty3270_add_attributes(struct tty3270_line *line, struct tty3270_attribute *attr,
+				    char *cp)
+{
+	struct tty3270_cell *cell;
+	int i;
 
-	/* Write 3270 data fragment. */
-	cp = s->string;
 	*cp++ = TO_SBA;
 	*cp++ = 0;
 	*cp++ = 0;
 
-	highlight = TAX_RESET;
-	f_color = TAC_RESET;
-	b_color = TAC_RESET;
 	for (i = 0, cell = line->cells; i < line->len; i++, cell++) {
-		if (cell->attributes.highlight != highlight) {
+		if (cell->attributes.highlight != attr->highlight) {
 			*cp++ = TO_SA;
 			*cp++ = TAT_EXTHI;
 			*cp++ = cell->attributes.highlight;
-			highlight = cell->attributes.highlight;
+			attr->highlight = cell->attributes.highlight;
 		}
-		if (cell->attributes.f_color != f_color) {
+		if (cell->attributes.f_color != attr->f_color) {
 			*cp++ = TO_SA;
 			*cp++ = TAT_FGCOLOR;
 			*cp++ = cell->attributes.f_color;
-			f_color = cell->attributes.f_color;
+			attr->f_color = cell->attributes.f_color;
 		}
-		if (cell->attributes.b_color != b_color) {
+		if (cell->attributes.b_color != attr->b_color) {
 			*cp++ = TO_SA;
 			*cp++ = TAT_BGCOLOR;
 			*cp++ = cell->attributes.b_color;
-			b_color = cell->attributes.b_color;
+			attr->b_color = cell->attributes.b_color;
 		}
 		if (cell->attributes.alternate_charset)
 			*cp++ = TO_GE;
-
 		*cp++ = cell->character;
 	}
-	if (highlight != TAX_RESET) {
-		*cp++ = TO_SA;
-		*cp++ = TAT_EXTHI;
-		*cp++ = TAX_RESET;
-	}
-	if (f_color != TAC_RESET) {
-		*cp++ = TO_SA;
-		*cp++ = TAT_FGCOLOR;
-		*cp++ = TAC_RESET;
-	}
-	if (b_color != TAC_RESET) {
-		*cp++ = TO_SA;
-		*cp++ = TAT_BGCOLOR;
-		*cp++ = TAC_RESET;
-	}
-	if (line->len < tp->view.cols) {
-		*cp++ = TO_RA;
-		*cp++ = 0;
-		*cp++ = 0;
-		*cp++ = 0;
-	}
+	return cp;
+}
 
+static void tty3270_reset_attributes(struct tty3270_attribute *attr)
+{
+	attr->highlight = TAX_RESET;
+	attr->f_color = TAC_RESET;
+	attr->b_color = TAC_RESET;
+}
+
+/*
+ * Convert a tty3270_line to a 3270 data fragment usable for output.
+ */
+static void tty3270_convert_line(struct tty3270 *tp, int line_nr)
+{
+	struct tty3270_line *line = tp->screen + line_nr;
+	struct tty3270_attribute attr;
+	struct string *s;
+	int flen, i;
+	char *cp;
+
+	/* Determine how long the fragment will be. */
+	flen = tty3270_required_length(tp, line_nr);
+	/* Find the line in the list. */
+	i = tp->view.rows - 2 - line_nr;
+	list_for_each_entry_reverse(s, &tp->lines, list)
+		if (--i <= 0)
+			break;
+	/*
+	 * Check if the line needs to get reallocated.
+	 */
+	if (s->len != flen)
+		s = tty3270_resize_line(tp, s, flen);
+
+	/* Write 3270 data fragment. */
+	tty3270_reset_attributes(&attr);
+	cp = tty3270_add_attributes(line, &attr, s->string);
+	cp = tty3270_add_reset_attributes(tp, line, cp, &attr);
 	if (tp->nr_up + line_nr < tp->view.rows - 2) {
 		/* Line is currently visible on screen. */
 		tty3270_update_string(tp, s, line_nr);
@@ -1297,13 +1329,6 @@ static void tty3270_ri(struct tty3270 *tp)
 	}
 }
 
-static void tty3270_reset_attributes(struct tty3270_attribute *attr)
-{
-	attr->highlight = TAX_RESET;
-	attr->f_color = TAC_RESET;
-	attr->b_color = TAC_RESET;
-}
-
 static void tty3270_reset_cell(struct tty3270 *tp, struct tty3270_cell *cell)
 {
 	cell->character = tp->view.ascebc[' '];