From 6ff4b38d6378f36dc11acd6bee4c676f41462cc1 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Tue, 9 Jul 2024 02:09:07 -0400
Subject: kernel: cons: Improve char handling and add cursor

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/dev/cons/cons.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 56 insertions(+), 4 deletions(-)

(limited to 'sys/dev/cons/cons.c')

diff --git a/sys/dev/cons/cons.c b/sys/dev/cons/cons.c
index 4c83c62..bf03469 100644
--- a/sys/dev/cons/cons.c
+++ b/sys/dev/cons/cons.c
@@ -33,10 +33,30 @@
 #include <dev/video/fbdev.h>
 #include <dev/cons/font.h>
 #include <dev/cons/cons.h>
+#include <vm/dynalloc.h>
 #include <string.h>
 
 struct cons_screen g_root_scr = {0};
 
+/*
+ * Create a chracter descriptor for drawing
+ * characters.
+ *
+ * @c: Character.
+ * @fg: Foreground.
+ * @bg: Background.
+ */
+static inline struct cons_char
+cons_make_char(char c, uint32_t fg, uint32_t bg)
+{
+    struct cons_char ch;
+
+    ch.fg = fg;
+    ch.bg = bg;
+    ch.c = c;
+    return ch;
+}
+
 /*
  * Render a character onto the screen.
  *
@@ -46,8 +66,10 @@ struct cons_screen g_root_scr = {0};
  * @y: Y position of char.
  */
 static void
-cons_render_char(struct cons_screen *scr, char c, uint32_t x, uint32_t y)
+cons_render_char(struct cons_screen *scr, struct cons_char ch,
+                 uint32_t x, uint32_t y)
 {
+    char c = ch.c;
     size_t idx;
     const uint8_t *glyph;
 
@@ -59,11 +81,32 @@ cons_render_char(struct cons_screen *scr, char c, uint32_t x, uint32_t y)
     for (uint32_t cy = 0; cy < FONT_HEIGHT; ++cy) {
         for (uint32_t cx = 0; cx < FONT_WIDTH; ++cx) {
             idx = fbdev_get_index(&scr->fbdev, x+FONT_WIDTH-cx, y+cy);
-            scr->fb_mem[idx] = ISSET(glyph[cy], BIT(cx)) ? scr->fg : scr->bg;
+            scr->fb_mem[idx] = ISSET(glyph[cy], BIT(cx)) ? ch.fg : ch.bg;
         }
     }
 }
 
+static void
+cons_draw_cursor(struct cons_screen *scr, uint32_t color)
+{
+    struct cons_char cursor_chr;
+
+    cursor_chr.fg = scr->fg;
+    cursor_chr.bg = color;
+    cursor_chr.c = ' ';
+    cons_render_char(scr, cursor_chr, scr->curs_col * FONT_WIDTH,
+        scr->curs_row * FONT_HEIGHT);
+}
+
+static void
+cons_move_cursor(struct cons_screen *scr, uint32_t col, uint32_t row)
+{
+    cons_draw_cursor(scr, scr->bg);
+    scr->curs_col = col;
+    scr->curs_row = row;
+    cons_draw_cursor(scr, scr->last_chr.fg);
+}
+
 /*
  * Clear the screen.
  *
@@ -96,6 +139,7 @@ cons_handle_special(struct cons_screen *scr, char c)
         /* Make a newline */
         scr->ch_col = 0;
         ++scr->ch_row;
+        cons_move_cursor(scr, 0, scr->curs_row + 1);
         return 0;
     }
 
@@ -112,17 +156,20 @@ cons_handle_special(struct cons_screen *scr, char c)
 int
 cons_putch(struct cons_screen *scr, char c)
 {
+    struct cons_char cons_chr;
+
     if (scr->ch_col > scr->ncols) {
         /* Make a newline as we past the max col */
         scr->ch_col = 0;
         ++scr->ch_row;
     }
 
-    if (scr->ch_row > scr->nrows) {
+    if (scr->curs_row >= scr->nrows) {
         /* Went over the screen size */
         scr->ch_col = 0;
         scr->ch_row = 0;
         cons_clear_scr(scr, scr->bg);
+        cons_move_cursor(scr, 0, 0);
     }
 
     /*
@@ -133,7 +180,12 @@ cons_putch(struct cons_screen *scr, char c)
         return 0;
     }
 
-    cons_render_char(scr, c, scr->ch_col * FONT_WIDTH,
+    cons_chr = cons_make_char(c, scr->fg, scr->bg);
+    scr->last_chr = cons_chr;
+
+    /* Draw cursor and character */
+    cons_move_cursor(scr, scr->curs_col + 1, scr->curs_row);
+    cons_render_char(scr, cons_chr, scr->ch_col * FONT_WIDTH,
         scr->ch_row * FONT_HEIGHT);
 
     ++scr->ch_col;
-- 
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