From 571cb05e0560f7e363b362e87648e32986da616a Mon Sep 17 00:00:00 2001
From: Witold Filipczyk <witekfl@poczta.onet.pl>
Date: Wed, 14 Dec 2022 22:04:01 +0100
Subject: [PATCH] [screen] Added struct bitfield dirty to screen

---
 src/terminal/screen.c | 20 ++++++++++++++++++++
 src/terminal/screen.h | 10 ++++------
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/terminal/screen.c b/src/terminal/screen.c
index 984c9f68..87f4de93 100644
--- a/src/terminal/screen.c
+++ b/src/terminal/screen.c
@@ -24,6 +24,7 @@
 #ifdef CONFIG_TERMINFO
 #include "terminal/terminfo.h"
 #endif
+#include "util/bitfield.h"
 #include "util/conv.h"
 #include "util/error.h"
 #include "util/memory.h"
@@ -442,6 +443,16 @@ static const struct screen_driver_opt *const screen_driver_opts[] = {
 
 static INIT_LIST_OF(struct screen_driver, active_screen_drivers);
 
+void
+set_screen_dirty(struct terminal_screen *screen, int from, int to)
+{
+	for (unsigned int i = from; i <= to; i++) {
+		set_bitfield_bit(screen->dirty, i);
+	}
+	int_upper_bound(&screen->dirty_from, from);
+	int_lower_bound(&screen->dirty_to, to);
+}
+
 /** Set screen_driver.opt according to screen_driver.type and @a term_spec.
  * Other members of @a *driver need not have been initialized.
  *
@@ -1312,6 +1323,7 @@ add_char_true(struct string *screen, struct screen_driver *driver,
 	int_upper_bound(&screen->dirty_to, ymax);				\
 										\
 	for (; y <= screen->dirty_to; y++) {					\
+		if (!test_bitfield_bit(screen->dirty, y)) continue;		\
 		int ypos = y * (term_)->width;					\
 		struct screen_char *current = &screen->last_image[ypos];	\
 		struct screen_char *pos = &screen->image[ypos];			\
@@ -1319,6 +1331,7 @@ add_char_true(struct string *screen, struct screen_driver *driver,
 		int is_last_line = (y == ymax);					\
 		int x = 0;						\
 		int dirty = 0;						\
+		clear_bitfield_bit(screen->dirty, y);				\
 										\
 		for (; x <= xmax; x++, current++, pos++) {			\
 			/*  Workaround for terminals without
@@ -1494,6 +1507,7 @@ resize_screen(struct terminal *term, int width, int height)
 {
 	struct terminal_screen *screen;
 	struct screen_char *image;
+	struct bitfield *new_dirty;
 	size_t size, bsize;
 
 	assert(term && term->screen);
@@ -1506,6 +1520,9 @@ resize_screen(struct terminal *term, int width, int height)
 	size = width * height;
 	if (size <= 0) return;
 
+	new_dirty = init_bitfield(height);
+	if (!new_dirty) return;
+
 	bsize = size * sizeof(*image);
 
 	image = (struct screen_char *)mem_realloc(screen->image, bsize * 2);
@@ -1519,6 +1536,8 @@ resize_screen(struct terminal *term, int width, int height)
 
 	term->width = width;
 	term->height = height;
+	mem_free_set(&screen->dirty, new_dirty);
+
 	set_screen_dirty(screen, 0, height);
 }
 
@@ -1526,6 +1545,7 @@ void
 done_screen(struct terminal_screen *screen)
 {
 	mem_free_if(screen->image);
+	mem_free(screen->dirty);
 	mem_free(screen);
 }
 
diff --git a/src/terminal/screen.h b/src/terminal/screen.h
index 7ed3bf2f..9b70fb4c 100644
--- a/src/terminal/screen.h
+++ b/src/terminal/screen.h
@@ -5,6 +5,7 @@
 extern "C" {
 #endif
 
+struct bitfield;
 struct module;
 struct screen_char;
 struct terminal;
@@ -24,15 +25,12 @@ struct terminal_screen {
 	/** The range of line numbers that are out of sync with the physical
 	 * screen. #dirty_from > #dirty_to means not dirty. */
 	int dirty_from, dirty_to;
+
+	struct bitfield *dirty;
 };
 
 /** Mark the screen ready for redrawing. */
-static inline void
-set_screen_dirty(struct terminal_screen *screen, int from, int to)
-{
-	int_upper_bound(&screen->dirty_from, from);
-	int_lower_bound(&screen->dirty_to, to);
-}
+void set_screen_dirty(struct terminal_screen *screen, int from, int to);
 
 /** Initializes a screen. Returns NULL upon allocation failure. */
 struct terminal_screen *init_screen(void);