--- lbbs/src/str_process.c	2025/07/02 04:17:33	1.20
+++ lbbs/src/str_process.c	2025/11/04 13:49:51	1.23
@@ -1,22 +1,15 @@
-/***************************************************************************
-						  str_process.c  -  description
-							 -------------------
-	Copyright            : (C) 2004-2025 by Leaflet
-	Email                : leaflet@leafok.com
- ***************************************************************************/
-
-/***************************************************************************
- *                                                                         *
- *   This program is free software; you can redistribute it and/or modify  *
- *   it under the terms of the GNU General Public License as published by  *
- *   the Free Software Foundation; either version 3 of the License, or     *
- *   (at your option) any later version.                                   *
- *                                                                         *
- ***************************************************************************/
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * str_process
+ *   - common string processing features with UTF-8 support
+ *
+ * Copyright (C) 2004-2025 by Leaflet <leaflet@leafok.com>
+ */
 
 #include "common.h"
 #include "log.h"
 #include "str_process.h"
+#include <ctype.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -37,22 +30,33 @@ int str_length(const char *str, int skip
 
 		if (skip_ctrl_seq && c == '\033' && str[i + 1] == '[') // Skip control sequence
 		{
-			i += 2;
-			while (str[i] != '\0' && str[i] != 'm')
+			for (i = i + 2; isdigit(str[i]) || str[i] == ';' || str[i] == '?'; i++)
+				;
+
+			if (str[i] == 'm') // valid
 			{
-				i++;
+				// skip
+			}
+			else if (isalpha(str[i]))
+			{
+				// unsupported ANSI CSI command
+			}
+			else
+			{
+				i--;
 			}
+
 			continue;
 		}
 
 		// Process UTF-8 Chinese characters
-		if (c & 0b10000000) // head of multi-byte character
+		if (c & 0x80) // head of multi-byte character
 		{
-			c = (c & 0b01110000) << 1;
-			while (c & 0b10000000)
+			c = (c & 0x70) << 1;
+			while (c & 0x80)
 			{
 				i++;
-				c = (c & 0b01111111) << 1;
+				c = (c & 0x7f) << 1;
 			}
 
 			ret += 2;
@@ -92,18 +96,18 @@ int split_line(const char *buffer, int m
 			continue;
 		}
 
-		if (c & 0b10000000) // head of multi-byte character
+		if (c & 0x80) // head of multi-byte character
 		{
 			if (*p_display_len + 2 > max_display_len)
 			{
 				break;
 			}
 
-			c = (c & 0b01110000) << 1;
-			while (c & 0b10000000)
+			c = (c & 0x70) << 1;
+			while (c & 0x80)
 			{
 				i++;
-				c = (c & 0b01111111) << 1;
+				c = (c & 0x7f) << 1;
 			}
 
 			(*p_display_len) += 2;