From 04360877619f3b9908c34aa57dcca37a387e1830 Mon Sep 17 00:00:00 2001
From: cowmonk <rekketstone@duck.com>
Date: Thu, 23 Jan 2025 08:45:09 -0700
Subject: [PATCH] UTF-8 Fixes, attempt at scrolling, & minor changes

Changed some global -> local const vars
---
 cowterm.c | 89 ++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 61 insertions(+), 28 deletions(-)

diff --git a/cowterm.c b/cowterm.c
index 6fae07f..c8df53d 100644
--- a/cowterm.c
+++ b/cowterm.c
@@ -21,10 +21,10 @@
 #include "config.h"
 
 // There isn't a need for MAX_ROWS or MAX_COLS, but ¯\_(ツ)_/¯
-#define MAX_ROWS 1000
-#define MAX_COLS 1000
-#define CHAR_WIDTH 8
-#define CHAR_HEIGHT 16
+const int MAX_ROWS = 1000;
+const int MAX_COLS = 1000;
+const int CHAR_WIDTH = 8;
+const int CHAR_HEIGHT = 16;
 
 // General window/terminal stuff
 static pid_t child_pid;
@@ -1250,40 +1250,61 @@ static int master_cb(int fd, void *data, Window window) {
       default:
         if (cursor_y >= term_rows || cursor_x >= term_cols)
           break;
-        if ((buf[i] >= 32 && buf[i] <= 126) || buf[i] == '\t') {
+        if (buf[i] & 0x80) { // UTF-8
+          char mb_buf[MB_CUR_MAX];
+          int mb_len = 0;
+          int j = i;
+          while (mb_len < (int)MB_CUR_MAX && j < n) {
+            if (mb_len == 0) {
+              if ((buf[j] & 0x80) == 0)
+                break;
+              mb_buf[mb_len] = buf[j];
+              mb_len++;
+            } else if ((buf[j] & 0xC0) == 0x80) {
+              mb_buf[mb_len] = buf[j];
+              mb_len++;
+            } else {
+              break;
+            }
+            j++;
+          }
+          if (mb_len > 0) {
+            wchar_t wc;
+            mbstate_t ps;
+            memset(&ps, 0, sizeof(ps));
+            if (mbrtowc(&wc, mb_buf, mb_len, &ps) > 0) {
+              terminal_buffer[cursor_y][cursor_x] = wc;
+              color_buffer[cursor_y][cursor_x] = current_color;
+              attr_buffer[cursor_y][cursor_x] = current_attr;
+              bg_color_buffer[cursor_y][cursor_x] = current_bg_color;
+              needs_refresh = 1;
+              cursor_x++;
+              if (cursor_x >= term_cols) {
+                cursor_x = 0;
+                cursor_y++;
+                if (cursor_y >= term_rows) {
+                  scroll_region_up(1);
+                  cursor_y = term_rows - 1;
+                }
+              }
+            }
+            i += mb_len - 1;
+          }
+        } else if (buf[i] >= 32) {
           terminal_buffer[cursor_y][cursor_x] = buf[i];
           color_buffer[cursor_y][cursor_x] = current_color;
           attr_buffer[cursor_y][cursor_x] = current_attr;
           bg_color_buffer[cursor_y][cursor_x] = current_bg_color;
           needs_refresh = 1;
-          if (++cursor_x >= term_cols) {
+          cursor_x++;
+          if (cursor_x >= term_cols) {
             cursor_x = 0;
-            if (++cursor_y >= term_rows) {
+            cursor_y++;
+            if (cursor_y >= term_rows) {
               scroll_region_up(1);
               cursor_y = term_rows - 1;
             }
           }
-        } else if (buf[i] & 0x80) { // UTF-8
-          mbstate_t ps;
-          memset(&ps, 0, sizeof(ps));
-          wchar_t wc;
-          size_t len = mbrtowc(&wc, buf + i, n - i, &ps);
-
-          if (len != (size_t)-1 && len != (size_t)-2 && len != 0) {
-            terminal_buffer[cursor_y][cursor_x] = wc;
-            color_buffer[cursor_y][cursor_x] = current_color;
-            attr_buffer[cursor_y][cursor_x] = current_attr;
-            bg_color_buffer[cursor_y][cursor_x] = current_bg_color;
-            needs_refresh = 1;
-            if (++cursor_x >= term_cols) {
-              cursor_x = 0;
-              if (++cursor_y >= term_rows) {
-                scroll_region_up(1);
-                cursor_y = term_rows - 1;
-              }
-            }
-            i += len - 1; // -1 because loop will increment i
-          }
         }
         break;
       }
@@ -1328,6 +1349,18 @@ static void key_press_cb(XKeyEvent *event, void *data) {
     return;
   }
 
+  if (event->state & ShiftMask) {
+    if (keysym == XK_Page_Up) {
+      scroll_region_up(term_rows / 2);
+      needs_refresh = 1;
+      return;
+    } else if (keysym == XK_Page_Down) {
+      scroll_region_down(term_rows / 2);
+      needs_refresh = 1;
+      return;
+    }
+  }
+
   if (keysym == XK_Return || keysym == XK_KP_Enter) {
     write(*master, "\r", 1); // Shell handles return
   } else if (keysym == XK_BackSpace) {