add bad char support

stepmania/src/FontManager.cpp

@@ -415,6 +415,8 @@ Font* FontManager::LoadFont( const CString &sFontOrTextureFilePath, CString sCha
 		CharAliases["menuright"]	= 0x100007;
 		CharAliases["start"]		= 0x100008;
 
+		CharAliases["invalid"]		= INVALID_CHAR; /* 0xFFFFFF */
+
 		for(aliasmap::const_iterator i = CharAliases.begin(); i != CharAliases.end(); ++i)
 		{
 			CString from = ssprintf("&%s;", i->first.GetString());

stepmania/src/RageUtil.cpp

@@ -903,6 +903,8 @@ longchar utf8_get_char (const char *p)
   return result;
 }
 
+const longchar INVALID_CHAR = 0xFFFFFF;
+
 lstring CStringToLstring(const CString &str)
 {
 	const char *ptr = str.c_str(), *end = str.c_str()+str.size();
@@ -912,6 +914,9 @@ lstring CStringToLstring(const CString &str)
 	while(ptr && ptr != end)
 	{
 		longchar c = utf8_get_char (ptr);
+		if(c == -1)
+			ret.push_back(INVALID_CHAR);
+		else
 			ret.push_back(c);
 		ptr = utf8_find_next_char (ptr, end);
 	}

stepmania/src/RageUtil.h

@@ -153,6 +153,7 @@ void splitrelpath(
  * be 16-bit.  This is mostly used within the font and text system. */
 typedef int longchar;
 typedef basic_string<longchar> lstring;
+extern const longchar INVALID_CHAR;
 
 lstring CStringToLstring(const CString &str);
 CString LcharToUTF8( longchar c );