From 69ea470a26b5b9b710d099a8764e9d7cbf2fe2ab Mon Sep 17 00:00:00 2001
From: Evgeny Pestov <pestoffne@vtomske.ru>
Date: Fri, 17 Dec 2021 00:49:16 +0700
Subject: [PATCH] CEdit::MoveChar never moves cursor between bytes of one UTF-8
 symbol

---
 src/ui/controls/edit.cpp | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/ui/controls/edit.cpp b/src/ui/controls/edit.cpp
index d9d31605..037a8d06 100644
--- a/src/ui/controls/edit.cpp
+++ b/src/ui/controls/edit.cpp
@@ -2261,7 +2261,7 @@ void CEdit::MoveChar(int move, bool bWord, bool bSelect)
 {
     int     character;
 
-    if ( move == -1 )  // back?
+    if ( move == -1 )  // back
     {
         if ( bWord )
         {
@@ -2306,12 +2306,15 @@ void CEdit::MoveChar(int move, bool bWord, bool bSelect)
         }
         else
         {
-            m_cursor1 --;
-            if ( m_cursor1 < 0 )  m_cursor1 = 0;
+            if ( m_cursor1 > 0 )
+            {
+                m_cursor1 --;
+                while ( m_cursor1 > 0 && (m_text[m_cursor1] & 0xC0) == 0x80 )  m_cursor1 --;
+            }
         }
     }
 
-    if ( move == 1 )  // advance?
+    if ( move == 1 )  // advance
     {
         if ( bWord )
         {
@@ -2356,8 +2359,11 @@ void CEdit::MoveChar(int move, bool bWord, bool bSelect)
         }
         else
         {
-            m_cursor1 ++;
-            if ( m_cursor1 > m_len )  m_cursor1 = m_len;
+            if ( m_cursor1 < m_len )
+            {
+                m_cursor1 ++;
+                while ( m_cursor1 < m_len && (m_text[m_cursor1] & 0xC0) == 0x80 )  m_cursor1 ++;
+            }
         }
     }