term: performance: use a bitfield to track which ascii printer to use

The things affecting which ASCII printer we use have grown...

Instead of checking everything inside term_update_ascii_printer(), use
a bitfield.

Anything affecting the printer used, must now set a bit in this
bitfield. This makes term_update_ascii_printer() much faster, since
all it needs to do is check if the bitfield is zero or not.

csi.c

@@ -33,13 +33,12 @@ static void
 sgr_reset(struct terminal *term)
 {
     /* TODO: can we drop this check? */
-    const enum curly_style curly_style = term->vt.curly.style;
-
     memset(&term->vt.attrs, 0, sizeof(term->vt.attrs));
     memset(&term->vt.curly, 0, sizeof(term->vt.curly));
 
-    if (unlikely(curly_style > CURLY_SINGLE))
+    term->bits_affecting_ascii_printer.curly_style = false;
-        term_update_ascii_printer(term);
+    term->bits_affecting_ascii_printer.curly_color = false;
+    term_update_ascii_printer(term);
 }
 
 static const char *
@@ -107,6 +106,7 @@ csi_sgr(struct terminal *term)
                 case CURLY_NONE:
                     term->vt.attrs.underline = false;
                     term->vt.curly.style = CURLY_NONE;
+                    term->bits_affecting_ascii_printer.curly_style = false;
                     break;
 
                 case CURLY_SINGLE:
@@ -114,7 +114,9 @@ csi_sgr(struct terminal *term)
                 case CURLY_CURLY:
                 case CURLY_DOTTED:
                 case CURLY_DASHED:
-                    term->vt.curly.style = style; break;
+                    term->vt.curly.style = style;
+                    term->bits_affecting_ascii_printer.curly_style =
+                        style > CURLY_SINGLE;
                     break;
                 }
 
@@ -134,6 +136,7 @@ csi_sgr(struct terminal *term)
         case 24: {
             term->vt.attrs.underline = false;
             term->vt.curly.style = CURLY_NONE;
+            term->bits_affecting_ascii_printer.curly_style = false;
             term_update_ascii_printer(term);
             break;
         }
@@ -236,6 +239,7 @@ csi_sgr(struct terminal *term)
             if (unlikely(param == 58)) {
                 term->vt.curly.color_src = src;
                 term->vt.curly.color = color;
+                term->bits_affecting_ascii_printer.curly_color = true;
                 term_update_ascii_printer(term);
             } else if (param == 38) {
                 term->vt.attrs.fg_src = src;
@@ -272,6 +276,7 @@ csi_sgr(struct terminal *term)
         case 59:
             term->vt.curly.color_src = COLOR_DEFAULT;
             term->vt.curly.color = 0;
+            term->bits_affecting_ascii_printer.curly_color = false;
             term_update_ascii_printer(term);
             break;
 
@@ -527,6 +532,9 @@ decset_decrst(struct terminal *term, unsigned param, bool enable)
             tll_free(term->alt.scroll_damage);
             term_damage_view(term);
         }
+
+        term->bits_affecting_ascii_printer.sixels =
+            tll_length(term->grid->sixel_images) > 0;
         term_update_ascii_printer(term);
         break;
 
@@ -1165,6 +1173,7 @@ csi_dispatch(struct terminal *term, uint8_t final)
             if (param == 4) {
                 /* Insertion Replacement Mode (IRM) */
                 term->insert_mode = sm;
+                term->bits_affecting_ascii_printer.insert_mode = sm;
                 term_update_ascii_printer(term);
                 break;
             }

sixel.c

@@ -420,6 +420,8 @@ sixel_scroll_up(struct terminal *term, int rows)
         }
     }
 
+    term->bits_affecting_ascii_printer.sixels =
+        tll_length(term->grid->sixel_images) > 0;
     term_update_ascii_printer(term);
     verify_sixels(term);
 }
@@ -444,6 +446,8 @@ sixel_scroll_down(struct terminal *term, int rows)
             break;
     }
 
+    term->bits_affecting_ascii_printer.sixels =
+        tll_length(term->grid->sixel_images) > 0;
     term_update_ascii_printer(term);
     verify_sixels(term);
 }
@@ -852,6 +856,8 @@ sixel_overwrite_by_rectangle(
     } else
         _sixel_overwrite_by_rectangle(term, start, col, height, width, NULL, NULL);
 
+    term->bits_affecting_ascii_printer.sixels =
+        tll_length(term->grid->sixel_images) > 0;
     term_update_ascii_printer(term);
 }
 
@@ -908,6 +914,8 @@ sixel_overwrite_by_row(struct terminal *term, int _row, int col, int width)
         }
     }
 
+    term->bits_affecting_ascii_printer.sixels =
+        tll_length(term->grid->sixel_images) > 0;
     term_update_ascii_printer(term);
 }
 
@@ -1387,6 +1395,9 @@ sixel_unhook(struct terminal *term)
     LOG_DBG("you now have %zu sixels in current grid",
             tll_length(term->grid->sixel_images));
 
+
+    term->bits_affecting_ascii_printer.sixels =
+        tll_length(term->grid->sixel_images) > 0;
     term_update_ascii_printer(term);
     render_refresh(term);
 }

terminal.c

@@ -2023,6 +2023,7 @@ term_reset(struct terminal *term, bool hard)
     term_ime_enable(term);
 #endif
 
+    term->bits_affecting_ascii_printer.value = 0;
     term_update_ascii_printer(term);
 
     if (!hard)
@@ -3021,6 +3022,9 @@ term_restore_cursor(struct terminal *term, const struct cursor *cursor)
 
     term->vt.attrs = term->vt.saved_attrs;
     term->charsets = term->saved_charsets;
+
+    term->bits_affecting_ascii_printer.charset =
+        term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
     term_update_ascii_printer(term);
 }
 
@@ -3801,21 +3805,21 @@ ascii_printer_single_shift(struct terminal *term, char32_t wc)
 {
     ascii_printer_generic(term, wc);
     term->charsets.selected = term->charsets.saved;
+
+    term->bits_affecting_ascii_printer.charset =
+        term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
     term_update_ascii_printer(term);
 }
 
 void
 term_update_ascii_printer(struct terminal *term)
 {
+    _Static_assert(sizeof(term->bits_affecting_ascii_printer) == sizeof(uint8_t), "bad size");
+
     void (*new_printer)(struct terminal *term, char32_t wc) =
-        unlikely(tll_length(term->grid->sixel_images) > 0 ||
+        unlikely(term->bits_affecting_ascii_printer.value != 0)
-                 term->vt.osc8.uri != NULL ||
+            ? &ascii_printer_generic
-                 term->vt.curly.style > CURLY_SINGLE ||
+            : &ascii_printer_fast;
-                 term->vt.curly.color_src != COLOR_DEFAULT ||
-                 term->charsets.set[term->charsets.selected] == CHARSET_GRAPHIC ||
-                 term->insert_mode)
-        ? &ascii_printer_generic
-        : &ascii_printer_fast;
 
 #if defined(_DEBUG) && LOG_ENABLE_DBG
     if (term->ascii_printer != new_printer) {
@@ -4108,6 +4112,8 @@ term_osc8_open(struct terminal *term, uint64_t id, const char *uri)
 
     term->vt.osc8.id = id;
     term->vt.osc8.uri = xstrdup(uri);
+
+    term->bits_affecting_ascii_printer.osc8 = true;
     term_update_ascii_printer(term);
 }
 
@@ -4117,6 +4123,7 @@ term_osc8_close(struct terminal *term)
     free(term->vt.osc8.uri);
     term->vt.osc8.uri = NULL;
     term->vt.osc8.id = 0;
+    term->bits_affecting_ascii_printer.osc8 = false;
     term_update_ascii_printer(term);
 }
 

terminal.h

@@ -393,6 +393,17 @@ struct terminal {
     const struct config *conf;
 
     void (*ascii_printer)(struct terminal *term, char32_t c);
+    union {
+        struct {
+            bool sixels:1;
+            bool osc8:1;
+            bool curly_style:1;
+            bool curly_color:1;
+            bool insert_mode:1;
+            bool charset:1;
+        };
+        uint8_t value;
+    } bits_affecting_ascii_printer;
 
     pid_t slave;
     int ptmx;

vt.c

@@ -243,12 +243,16 @@ action_execute(struct terminal *term, uint8_t c)
     case '\x0e':
         /* SO - shift out */
         term->charsets.selected = G1;
+        term->bits_affecting_ascii_printer.charset =
+            term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
         term_update_ascii_printer(term);
         break;
 
     case '\x0f':
         /* SI - shift in */
         term->charsets.selected = G0;
+        term->bits_affecting_ascii_printer.charset =
+            term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
         term_update_ascii_printer(term);
         break;
 
@@ -482,12 +486,16 @@ action_esc_dispatch(struct terminal *term, uint8_t final)
         case 'n':
             /* LS2 - Locking Shift 2 */
             term->charsets.selected = G2;
+            term->bits_affecting_ascii_printer.charset =
+                term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
             term_update_ascii_printer(term);
             break;
 
         case 'o':
             /* LS3 - Locking Shift 3 */
             term->charsets.selected = G3;
+            term->bits_affecting_ascii_printer.charset =
+                term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
             term_update_ascii_printer(term);
             break;
 
@@ -546,6 +554,8 @@ action_esc_dispatch(struct terminal *term, uint8_t final)
             size_t idx = term->vt.private - '(';
             xassert(idx <= G3);
             term->charsets.set[idx] = CHARSET_GRAPHIC;
+            term->bits_affecting_ascii_printer.charset =
+                term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
             term_update_ascii_printer(term);
             break;
         }
@@ -554,6 +564,8 @@ action_esc_dispatch(struct terminal *term, uint8_t final)
             size_t idx = term->vt.private - '(';
             xassert(idx <= G3);
             term->charsets.set[idx] = CHARSET_ASCII;
+            term->bits_affecting_ascii_printer.charset =
+                term->charsets.set[term->charsets.selected] != CHARSET_ASCII;
             term_update_ascii_printer(term);
             break;
         }