vt: move glyph determination to a separate function

No logical changes. Make it easier for enhancements to come.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Link: https://lore.kernel.org/r/20250507141535.40655-4-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 58fa1b285f22b95d00f818860b86c39b90f986d5..556af82a9231a40f5554ac56db8489d871751e16 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2925,6 +2925,7 @@ static void vc_con_rewind(struct vc_data *vc)
 
 #define UCS_ZWS                0x200b  /* Zero Width Space */
 #define UCS_VS16       0xfe0f  /* Variation Selector 16 */
+#define UCS_REPLACEMENT        0xfffd  /* Replacement Character */
 
 static int vc_process_ucs(struct vc_data *vc, int *c, int *tc)
 {
@@ -2984,12 +2985,38 @@ static int vc_process_ucs(struct vc_data *vc, int *c, int *tc)
        return 0;
 }
 
+static int vc_get_glyph(struct vc_data *vc, int tc)
+{
+       int glyph = conv_uni_to_pc(vc, tc);
+       u16 charmask = vc->vc_hi_font_mask ? 0x1ff : 0xff;
+
+       if (!(glyph & ~charmask))
+               return glyph;
+
+       if (glyph == -1)
+               return -1; /* nothing to display */
+
+       /* Glyph not found */
+       if ((!vc->vc_utf || vc->vc_disp_ctrl || tc < 128) && !(tc & ~charmask)) {
+               /*
+                * In legacy mode use the glyph we get by a 1:1 mapping.
+                * This would make absolutely no sense with Unicode in mind, but do this for
+                * ASCII characters since a font may lack Unicode mapping info and we don't
+                * want to end up with having question marks only.
+                */
+               return tc;
+       }
+
+       /* Display U+FFFD (Unicode Replacement Character). */
+       return conv_uni_to_pc(vc, UCS_REPLACEMENT);
+}
+
 static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
                struct vc_draw_region *draw)
 {
        int next_c;
        unsigned char vc_attr = vc->vc_attr;
-       u16 himask = vc->vc_hi_font_mask, charmask = himask ? 0x1ff : 0xff;
+       u16 himask = vc->vc_hi_font_mask;
        u8 width = 1;
        bool inverse = false;
 
@@ -3000,39 +3027,17 @@ static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
        }
 
        /* Now try to find out how to display it */
-       tc = conv_uni_to_pc(vc, tc);
-       if (tc & ~charmask) {
-               if (tc == -1)
-                       return -1; /* nothing to display */
+       tc = vc_get_glyph(vc, tc);
+       if (tc == -1)
+               return -1; /* nothing to display */
+       if (tc < 0) {
+               inverse = true;
+               tc = conv_uni_to_pc(vc, '?');
+               if (tc < 0)
+                       tc = '?';
 
-               /* Glyph not found */
-               if ((!vc->vc_utf || vc->vc_disp_ctrl || c < 128) &&
-                               !(c & ~charmask)) {
-                       /*
-                        * In legacy mode use the glyph we get by a 1:1
-                        * mapping.
-                        * This would make absolutely no sense with Unicode in
-                        * mind, but do this for ASCII characters since a font
-                        * may lack Unicode mapping info and we don't want to
-                        * end up with having question marks only.
-                        */
-                       tc = c;
-               } else {
-                       /*
-                        * Display U+FFFD. If it's not found, display an inverse
-                        * question mark.
-                        */
-                       tc = conv_uni_to_pc(vc, 0xfffd);
-                       if (tc < 0) {
-                               inverse = true;
-                               tc = conv_uni_to_pc(vc, '?');
-                               if (tc < 0)
-                                       tc = '?';
-
-                               vc_attr = vc_invert_attr(vc);
-                               con_flush(vc, draw);
-                       }
-               }
+               vc_attr = vc_invert_attr(vc);
+               con_flush(vc, draw);
        }
 
        next_c = c;