bugfix(network): Prevent LAN lobby hang with long player names

Core/GameEngine/Include/GameNetwork/LANAPI.h

@@ -262,6 +262,7 @@ struct LANMessage
 		{
 			char options[m_lanMaxOptionsLength+1];
 		} GameOptions;
+		static_assert(ARRAY_SIZE(GameOptions.options) > m_lanMaxOptionsLength, "GameOptions.options buffer must be larger than m_lanMaxOptionsLength");
 
 	};
 };

Core/GameEngine/Source/GameNetwork/GameInfo.cpp

@@ -44,6 +44,7 @@
 #include "GameNetwork/LANAPI.h"						// for testing packet size
 #include "GameNetwork/LANAPICallbacks.h"	// for testing packet size
 #include "WWLib/strtok_r.h"
+#include "WWLib/utf8.h"
 
 
 
@@ -891,6 +892,20 @@ Bool GameInfo::isSandbox()
 
 static const char slotListID		= 'S';
 
+// TheSuperHackers @bugfix Truncates the name to at most maxByteCount bytes without splitting
+// a multibyte UTF-8 character. A non-positive budget empties the name; retail spun forever
+// there, because removing the last character of an already empty string is a no-op.
+static void truncatePlayerName(AsciiString& name, Int maxByteCount)
+{
+	if (maxByteCount <= 0)
+	{
+		name.clear();
+		return;
+	}
+
+	name.truncateTo(static_cast<Int>(Utf8_Truncate_Len(name.str(), name.getLength(), maxByteCount)));
+}
+
 AsciiString GameInfoToAsciiString( const GameInfo *game )
 {
 	if (!game)
@@ -953,8 +968,7 @@ AsciiString GameInfoToAsciiString( const GameInfo *game )
 			int lenRem = m_lanMaxOptionsLength - lenCur;  //length remaining before overflowing
 			int lenMax = lenRem / (MAX_SLOTS-i);  //share lenRem with all remaining slots
 			AsciiString name = WideCharStringToMultiByte(slot->getName().str()).c_str();
-			while( name.getLength() > lenMax )
-				name.removeLastChar();  //what a horrible way to truncate.  I hate AsciiString.
+			truncatePlayerName( name, lenMax );
 
 			str.format( "H%s%s", name.str(), tmp.str() );
 		}
@@ -988,7 +1002,7 @@ AsciiString GameInfoToAsciiString( const GameInfo *game )
 	}
 	optionsString.concat(';');
 
-	DEBUG_ASSERTCRASH(!TheLAN || (optionsString.getLength() < m_lanMaxOptionsLength),
+	DEBUG_ASSERTCRASH(!TheLAN || (optionsString.getLength() <= m_lanMaxOptionsLength),
 		("WARNING: options string is longer than expected!  Length is %d, but max is %d!",
 		optionsString.getLength(), m_lanMaxOptionsLength));
 

Core/GameEngine/Source/GameNetwork/LANAPI.cpp

@@ -834,7 +834,7 @@ void LANAPI::RequestGameStartTimer( Int seconds )
 
 void LANAPI::RequestGameOptions( AsciiString gameOptions, Bool isPublic, UnsignedInt ip /* = 0 */ )
 {
-	DEBUG_ASSERTCRASH(gameOptions.getLength() < m_lanMaxOptionsLength, ("Game options string is too long!"));
+	DEBUG_ASSERTCRASH(gameOptions.getLength() <= m_lanMaxOptionsLength, ("Game options string is too long!"));
 
 	if (!m_currentGame)
 		return;

Core/Libraries/Source/WWVegas/WWLib/CMakeLists.txt

@@ -134,6 +134,8 @@ set(WWLIB_SRC
     trim.cpp
     trim.h
     uarray.h
+    utf8.cpp
+    utf8.h
     vector.cpp
     Vector.h
     visualc.h

Core/Libraries/Source/WWVegas/WWLib/utf8.cpp

@@ -0,0 +1,41 @@
+/*
+**	Command & Conquer Generals Zero Hour(tm)
+**	Copyright 2026 TheSuperHackers
+**
+**	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.
+**
+**	This program is distributed in the hope that it will be useful,
+**	but WITHOUT ANY WARRANTY; without even the implied warranty of
+**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+**	GNU General Public License for more details.
+**
+**	You should have received a copy of the GNU General Public License
+**	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "always.h"
+#include "utf8.h"
+
+// A UTF-8 continuation byte matches 10xxxxxx, so it can never start a sequence.
+static bool Utf8_Is_Continuation_Byte(char c)
+{
+	return ((unsigned char)c & 0xC0) == 0x80;
+}
+
+size_t Utf8_Truncate_Len(const char* src, size_t srcLen, size_t maxLen)
+{
+	if (srcLen <= maxLen)
+	{
+		return srcLen;
+	}
+
+	size_t len = maxLen;
+	while (len > 0 && Utf8_Is_Continuation_Byte(src[len]))
+	{
+		--len;
+	}
+	return len;
+}

Core/Libraries/Source/WWVegas/WWLib/utf8.h

@@ -0,0 +1,27 @@
+/*
+**	Command & Conquer Generals Zero Hour(tm)
+**	Copyright 2026 TheSuperHackers
+**
+**	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.
+**
+**	This program is distributed in the hope that it will be useful,
+**	but WITHOUT ANY WARRANTY; without even the implied warranty of
+**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+**	GNU General Public License for more details.
+**
+**	You should have received a copy of the GNU General Public License
+**	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stddef.h>
+
+// Returns the largest length not greater than maxLen at which the srcLen bytes of the UTF-8 string
+// src can be cut without splitting a multibyte sequence, by backing off the continuation bytes at
+// the cut point. Returns srcLen when the string already fits in maxLen. Returns 0 when no whole
+// sequence fits, which is also what malformed UTF-8 yields once it has no lead byte to back off to.
+size_t Utf8_Truncate_Len(const char* src, size_t srcLen, size_t maxLen);