include/wx/object.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/object.h
   3 // Purpose:     wxObject class, plus run-time type information macros
   4 // Author:      Julian Smart
   5 // Modified by: Ron Lee
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 1997 Julian Smart and Markus Holzem
   9 //              (c) 2001 Ron Lee <ron@debian.org>
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef _WX_OBJECTH__
  14 #define _WX_OBJECTH__
  15
  16 #ifdef __GNUG__
  17 #pragma interface "object.h"
  18 #endif
  19
  20 // ----------------------------------------------------------------------------
  21 // headers
  22 // ----------------------------------------------------------------------------
  23
  24 #include "wx/defs.h"
  25 #include "wx/memory.h"
  26
  27 class WXDLLEXPORT wxObject;
  28
  29 #if wxUSE_DYNAMIC_CLASSES
  30
  31 // ----------------------------------------------------------------------------
  32 // conditional compilation
  33 // ----------------------------------------------------------------------------
  34
  35 // this shouldn't be needed any longer as <wx/msw/private.h> does it but it
  36 // doesn't hurt neither
  37 #ifdef GetClassName
  38 #undef GetClassName
  39 #endif
  40 #ifdef GetClassInfo
  41 #undef GetClassInfo
  42 #endif
  43
  44 class WXDLLEXPORT wxClassInfo;
  45 class WXDLLEXPORT wxHashTable;
  46 class WXDLLEXPORT wxObjectRefData;
  47
  48 #if wxUSE_STD_IOSTREAM && (defined(__WXDEBUG__) || wxUSE_DEBUG_CONTEXT)
  49     #include "wx/ioswrap.h"
  50 #endif
  51
  52
  53 // ----------------------------------------------------------------------------
  54 // wxClassInfo
  55 // ----------------------------------------------------------------------------
  56
  57 typedef wxObject *(*wxObjectConstructorFn)(void);
  58
  59 class WXDLLEXPORT wxClassInfo
  60 {
  61 public:
  62     wxClassInfo( const wxChar *className,
  63                  const wxChar *baseName1,
  64                  const wxChar *baseName2,
  65                  int size,
  66                  wxObjectConstructorFn ctor )
  67         : m_className(className)
  68         , m_baseClassName1(baseName1)
  69         , m_baseClassName2(baseName2)
  70         , m_objectSize(size)
  71         , m_objectConstructor(ctor)
  72         , m_baseInfo1(0)
  73         , m_baseInfo2(0)
  74         , m_next(sm_first)
  75         { sm_first = this; }
  76
  77     wxObject *CreateObject() { return m_objectConstructor ? (*m_objectConstructor)() : 0; }
  78
  79     const wxChar       *GetClassName() const { return m_className; }
  80     const wxChar       *GetBaseClassName1() const { return m_baseClassName1; }
  81     const wxChar       *GetBaseClassName2() const { return m_baseClassName2; }
  82     const wxClassInfo  *GetBaseClass1() const { return m_baseInfo1; }
  83     const wxClassInfo  *GetBaseClass2() const { return m_baseInfo2; }
  84     int                 GetSize() const { return m_objectSize; }
  85
  86     wxObjectConstructorFn      GetConstructor() const { return m_objectConstructor; }
  87     static const wxClassInfo  *GetFirst() { return sm_first; }
  88     const wxClassInfo         *GetNext() const { return m_next; }
  89     static wxClassInfo        *FindClass(const wxChar *className);
  90
  91         // Climb upwards through inheritance hierarchy.
  92         // Dual inheritance is catered for.
  93
  94     bool IsKindOf(const wxClassInfo *info) const
  95     {
  96         return info != 0 &&
  97                ( info == this ||
  98                  ( m_baseInfo1 && m_baseInfo1->IsKindOf(info) ) ||
  99                  ( m_baseInfo2 && m_baseInfo2->IsKindOf(info) ) );
 100     }
 101
 102         // Initializes parent pointers and hash table for fast searching.
 103
 104     static void     InitializeClasses();
 105
 106         // Cleans up hash table used for fast searching.
 107
 108     static void     CleanUpClasses();
 109
 110 public:
 111     const wxChar            *m_className;
 112     const wxChar            *m_baseClassName1;
 113     const wxChar            *m_baseClassName2;
 114     int                      m_objectSize;
 115     wxObjectConstructorFn    m_objectConstructor;
 116
 117         // Pointers to base wxClassInfos: set in InitializeClasses
 118
 119     const wxClassInfo       *m_baseInfo1;
 120     const wxClassInfo       *m_baseInfo2;
 121
 122         // class info object live in a linked list:
 123         // pointers to its head and the next element in it
 124
 125     static wxClassInfo      *sm_first;
 126     wxClassInfo             *m_next;
 127
 128     // FIXME: this should be private (currently used directly by way too
 129     //        many clients)
 130     static wxHashTable      *sm_classTable;
 131
 132 private:
 133     // InitializeClasses() helper
 134     static wxClassInfo *GetBaseByName(const wxChar *name);
 135
 136     DECLARE_NO_COPY_CLASS(wxClassInfo)
 137 };
 138
 139 WXDLLEXPORT wxObject *wxCreateDynamicObject(const wxChar *name);
 140
 141 // ----------------------------------------------------------------------------
 142 // Dynamic class macros
 143 // ----------------------------------------------------------------------------
 144
 145 #define DECLARE_DYNAMIC_CLASS(name)           \
 146  public:                                      \
 147   static wxClassInfo sm_class##name;          \
 148   virtual wxClassInfo *GetClassInfo() const   \
 149    { return &name::sm_class##name; }
 150
 151 #define DECLARE_ABSTRACT_CLASS(name) DECLARE_DYNAMIC_CLASS(name)
 152 #define DECLARE_CLASS(name) DECLARE_DYNAMIC_CLASS(name)
 153
 154 // -----------------------------------
 155 // for concrete classes
 156 // -----------------------------------
 157
 158     // Single inheritance with one base class
 159
 160 #define IMPLEMENT_DYNAMIC_CLASS(name, basename)                 \
 161  wxObject* WXDLLEXPORT_CTORFN wxConstructorFor##name()          \
 162   { return new name; }                                          \
 163  wxClassInfo name::sm_class##name(wxT(#name), wxT(#basename),   \
 164             0, (int) sizeof(name),                              \
 165             (wxObjectConstructorFn) wxConstructorFor##name);
 166
 167     // Multiple inheritance with two base classes
 168
 169 #define IMPLEMENT_DYNAMIC_CLASS2(name, basename1, basename2)    \
 170  wxObject* WXDLLEXPORT_CTORFN wxConstructorFor##name()          \
 171   { return new name; }                                          \
 172  wxClassInfo name::sm_class##name(wxT(#name), wxT(#basename1),  \
 173             wxT(#basename2), (int) sizeof(name),                \
 174             (wxObjectConstructorFn) wxConstructorFor##name);
 175
 176 // -----------------------------------
 177 // for abstract classes
 178 // -----------------------------------
 179
 180     // Single inheritance with one base class
 181
 182 #define IMPLEMENT_ABSTRACT_CLASS(name, basename)                \
 183  wxClassInfo name::sm_class##name(wxT(#name), wxT(#basename),   \
 184             0, (int) sizeof(name), (wxObjectConstructorFn) 0);
 185
 186     // Multiple inheritance with two base classes
 187
 188 #define IMPLEMENT_ABSTRACT_CLASS2(name, basename1, basename2)   \
 189  wxClassInfo name::sm_class##name(wxT(#name), wxT(#basename1),  \
 190             wxT(#basename2), (int) sizeof(name),                \
 191             (wxObjectConstructorFn) 0);
 192
 193 #define IMPLEMENT_CLASS IMPLEMENT_ABSTRACT_CLASS
 194 #define IMPLEMENT_CLASS2 IMPLEMENT_ABSTRACT_CLASS2
 195
 196 // -----------------------------------
 197 // for pluggable classes
 198 // -----------------------------------
 199
 200     // NOTE: this should probably be the very first statement
 201     //       in the class declaration so wxPluginSentinel is
 202     //       the first member initialised and the last destroyed.
 203
 204 // _DECLARE_DL_SENTINEL(name) wxPluginSentinel m_pluginsentinel;
 205
 206 #if wxUSE_NESTED_CLASSES
 207
 208 #define _DECLARE_DL_SENTINEL(name, exportdecl)  \
 209 class exportdecl name##PluginSentinel {         \
 210 private:                                        \
 211     static const wxString sm_className;         \
 212 public:                                         \
 213     name##PluginSentinel();                     \
 214     ~name##PluginSentinel();                    \
 215 };                                              \
 216 name##PluginSentinel  m_pluginsentinel;
 217
 218 #define _IMPLEMENT_DL_SENTINEL(name)                                \
 219  const wxString name::name##PluginSentinel::sm_className(#name);    \
 220  name::name##PluginSentinel::name##PluginSentinel() {               \
 221     wxPluginLibrary *e = (wxPluginLibrary*) wxPluginLibrary::ms_classes.Get(#name);   \
 222     if( e != 0 ) { e->RefObj(); }                                      \
 223  }                                                                  \
 224  name::name##PluginSentinel::~name##PluginSentinel() {            \
 225     wxPluginLibrary *e = (wxPluginLibrary*) wxPluginLibrary::ms_classes.Get(#name);   \
 226     if( e != 0 ) { e->UnrefObj(); }                                 \
 227  }
 228 #else
 229
 230 #define _DECLARE_DL_SENTINEL(name)
 231 #define _IMPLEMENT_DL_SENTINEL(name)
 232
 233 #endif  // wxUSE_NESTED_CLASSES
 234
 235 #define DECLARE_PLUGGABLE_CLASS(name) \
 236  DECLARE_DYNAMIC_CLASS(name) _DECLARE_DL_SENTINEL(name, WXDLLEXPORT)
 237 #define DECLARE_ABSTRACT_PLUGGABLE_CLASS(name)  \
 238  DECLARE_ABSTRACT_CLASS(name) _DECLARE_DL_SENTINEL(name, WXDLLEXPORT)
 239
 240 #define DECLARE_USER_EXPORTED_PLUGGABLE_CLASS(name, usergoo) \
 241  DECLARE_DYNAMIC_CLASS(name) _DECLARE_DL_SENTINEL(name, usergoo)
 242 #define DECLARE_USER_EXPORTED_ABSTRACT_PLUGGABLE_CLASS(name, usergoo)  \
 243  DECLARE_ABSTRACT_CLASS(name) _DECLARE_DL_SENTINEL(name, usergoo)
 244
 245 #define IMPLEMENT_PLUGGABLE_CLASS(name, basename) \
 246  IMPLEMENT_DYNAMIC_CLASS(name, basename) _IMPLEMENT_DL_SENTINEL(name)
 247 #define IMPLEMENT_PLUGGABLE_CLASS2(name, basename1, basename2)  \
 248  IMPLEMENT_DYNAMIC_CLASS2(name, basename1, basename2) _IMPLEMENT_DL_SENTINEL(name)
 249 #define IMPLEMENT_ABSTRACT_PLUGGABLE_CLASS(name, basename) \
 250  IMPLEMENT_ABSTRACT_CLASS(name, basename) _IMPLEMENT_DL_SENTINEL(name)
 251 #define IMPLEMENT_ABSTRACT_PLUGGABLE_CLASS2(name, basename1, basename2)  \
 252  IMPLEMENT_ABSTRACT_CLASS2(name, basename1, basename2) _IMPLEMENT_DL_SENTINEL(name)
 253
 254 #define IMPLEMENT_USER_EXPORTED_PLUGGABLE_CLASS(name, basename) \
 255  IMPLEMENT_PLUGGABLE_CLASS(name, basename)
 256 #define IMPLEMENT_USER_EXPORTED_PLUGGABLE_CLASS2(name, basename1, basename2)  \
 257  IMPLEMENT_PLUGGABLE_CLASS2(name, basename1, basename2)
 258 #define IMPLEMENT_USER_EXPORTED_ABSTRACT_PLUGGABLE_CLASS(name, basename) \
 259  IMPLEMENT_ABSTRACT_PLUGGABLE_CLASS(name, basename)
 260 #define IMPLEMENT_USER_EXPORTED_ABSTRACT_PLUGGABLE_CLASS2(name, basename1, basename2)  \
 261  IMPLEMENT_ABSTRACT_PLUGGABLE_CLASS2(name, basename1, basename2)
 262
 263
 264 #define CLASSINFO(name) (&name::sm_class##name)
 265
 266 #else // !wxUSE_DYNAMIC_CLASSES
 267
 268     // No dynamic class system: so stub out the macros
 269
 270 #define DECLARE_DYNAMIC_CLASS(name)
 271 #define DECLARE_ABSTRACT_CLASS(name)
 272 #define DECLARE_CLASS(name)
 273 #define IMPLEMENT_DYNAMIC_CLASS(name, basename)
 274 #define IMPLEMENT_DYNAMIC_CLASS2(name, basename1, basename2)
 275 #define IMPLEMENT_ABSTRACT_CLASS(name, basename)
 276 #define IMPLEMENT_ABSTRACT_CLASS2(name, basename1, basename2)
 277 #define IMPLEMENT_CLASS IMPLEMENT_ABSTRACT_CLASS
 278 #define IMPLEMENT_CLASS2 IMPLEMENT_ABSTRACT_CLASS2
 279
 280 #define DECLARE_PLUGGABLE_CLASS(name)
 281 #define DECLARE_ABSTRACT_PLUGGABLE_CLASS(name)
 282 #define IMPLEMENT_PLUGGABLE_CLASS(name, basename)
 283 #define IMPLEMENT_PLUGGABLE_CLASS2(name, basename1, basename2)
 284 #define IMPLEMENT_ABSTRACT_PLUGGABLE_CLASS(name, basename)
 285 #define IMPLEMENT_ABSTRACT_PLUGGABLE_CLASS2(name, basename1, basename2)
 286
 287 #define DECLARE_USER_EXPORTED_PLUGGABLE_CLASS(name, usergoo)
 288 #define DECLARE_USER_EXPORTED_ABSTRACT_PLUGGABLE_CLASS(name, usergoo)
 289 #define IMPLEMENT_USER_EXPORTED_PLUGGABLE_CLASS(name, basename)
 290 #define IMPLEMENT_USER_EXPORTED_PLUGGABLE_CLASS2(name, basename1, basename2)
 291 #define IMPLEMENT_USER_EXPORTED_ABSTRACT_PLUGGABLE_CLASS(name, basename)
 292 #define IMPLEMENT_USER_EXPORTED_ABSTRACT_PLUGGABLE_CLASS2(name, basename1, basename2)
 293
 294 #endif // wxUSE_DYNAMIC_CLASSES
 295
 296
 297 #define wxIS_KIND_OF(obj, className) obj->IsKindOf(&className::sm_class##className)
 298
 299 // Just seems a bit nicer-looking (pretend it's not a macro)
 300 #define wxIsKindOf(obj, className) obj->IsKindOf(&className::sm_class##className)
 301
 302 // to be replaced by dynamic_cast<> in the future
 303 #define wxDynamicCast(obj, className) \
 304  (className *) wxCheckDynamicCast((wxObject*)(obj), &className::sm_class##className)
 305
 306 // The 'this' pointer is always true, so use this version
 307 // to cast the this pointer and avoid compiler warnings.
 308 #define wxDynamicCastThis(className) \
 309  (IsKindOf(&className::sm_class##className) ? (className *)(this) : (className *)0)
 310
 311 #define wxConstCast(obj, className) ((className *)(obj))
 312
 313
 314 #ifdef __WXDEBUG__
 315 inline void wxCheckCast(void *ptr)
 316 {
 317     wxASSERT_MSG( ptr, _T("wxStaticCast() used incorrectly") );
 318 }
 319 #define wxStaticCast(obj, className) \
 320  (wxCheckCast(wxDynamicCast(obj, className)), ((className *)(obj)))
 321
 322 #else  // !__WXDEBUG__
 323 #define wxStaticCast(obj, className) ((className *)(obj))
 324
 325 #endif  // __WXDEBUG__
 326
 327
 328 // for some reason Borland seems to need this include.
 329 #if wxUSE_STD_IOSTREAM                                \
 330     && (defined(__WXDEBUG__) || wxUSE_DEBUG_CONTEXT)  \
 331     && defined(__BORLANDC__)
 332     #if wxUSE_IOSTREAMH
 333         #include <iostream.h>
 334     #else
 335         #include <iostream>
 336     #endif
 337 #endif // wxUSE_IOSTREAMH
 338
 339 // ----------------------------------------------------------------------------
 340 // set up memory debugging macros
 341 // ----------------------------------------------------------------------------
 342
 343 /*
 344     Which new/delete operator variants do we want?
 345
 346     _WX_WANT_NEW_SIZET_WXCHAR_INT             = void *operator new (size_t size, wxChar *fileName = 0, int lineNum = 0)
 347     _WX_WANT_DELETE_VOID                      = void operator delete (void * buf)
 348     _WX_WANT_DELETE_VOID_CONSTCHAR_SIZET      = void operator delete (void *buf, const char *_fname, size_t _line)
 349     _WX_WANT_DELETE_VOID_WXCHAR_INT           = void operator delete(void *buf, wxChar*, int)
 350     _WX_WANT_ARRAY_NEW_SIZET_WXCHAR_INT       = void *operator new[] (size_t size, wxChar *fileName , int lineNum = 0)
 351     _WX_WANT_ARRAY_DELETE_VOID                = void operator delete[] (void *buf)
 352     _WX_WANT_ARRAY_DELETE_VOID_WXCHAR_INT     = void operator delete[] (void* buf, wxChar*, int )
 353 */
 354
 355 #if defined(__WXDEBUG__) && wxUSE_MEMORY_TRACING
 356
 357 // All compilers get this one
 358 #define _WX_WANT_NEW_SIZET_WXCHAR_INT
 359
 360 // Everyone except Visage gets the next one
 361 #ifndef __VISAGECPP__
 362     #define _WX_WANT_DELETE_VOID
 363 #endif
 364
 365 // Only visage gets this one under the correct circumstances
 366 #if defined(__VISAGECPP__) && __DEBUG_ALLOC__
 367     #define _WX_WANT_DELETE_VOID_CONSTCHAR_SIZET
 368 #endif
 369
 370 // Only VC++ 6.0 and CodeWarrior compilers get overloaded delete that matches new
 371 #if ( defined(__VISUALC__) && (__VISUALC__ >= 1200) ) || (defined(__MWERKS__) && (__MWERKS__ >= 0x2400))
 372     #define _WX_WANT_DELETE_VOID_WXCHAR_INT
 373 #endif
 374
 375 // Now see who (if anyone) gets the array memory operators
 376 #if wxUSE_ARRAY_MEMORY_OPERATORS
 377
 378     // Everyone except Visual C++ (cause problems for VC++ - crashes)
 379     #if !defined(__VISUALC__)
 380         #define _WX_WANT_ARRAY_NEW_SIZET_WXCHAR_INT
 381     #endif
 382
 383     // Everyone except Visual C++ (cause problems for VC++ - crashes)
 384     #if !defined(__VISUALC__)
 385         #define _WX_WANT_ARRAY_DELETE_VOID
 386     #endif
 387
 388     // Only CodeWarrior 6 or higher
 389     #if defined(__MWERKS__) && (__MWERKS__ >= 0x2400)
 390         #define _WX_WANT_ARRAY_DELETE_VOID_WXCHAR_INT
 391     #endif
 392
 393 #endif // wxUSE_ARRAY_MEMORY_OPERATORS
 394
 395 #endif // WXDEBUG && wxUSE_MEMORY_TRACING
 396
 397
 398 // ----------------------------------------------------------------------------
 399 // wxObject: the root class of wxWindows object hierarchy
 400 // ----------------------------------------------------------------------------
 401
 402 class WXDLLEXPORT wxObject
 403 {
 404     DECLARE_ABSTRACT_CLASS(wxObject)
 405
 406 private:
 407     void InitFrom(const wxObject& other);
 408
 409 public:
 410     wxObject() { m_refData = NULL; }
 411     virtual ~wxObject() { UnRef(); }
 412
 413     wxObject(const wxObject& other)
 414         {
 415             InitFrom(other);
 416         }
 417
 418     wxObject& operator=(const wxObject& other)
 419     {
 420         if ( this != &other )
 421         {
 422             UnRef();
 423             InitFrom(other);
 424         }
 425         return *this;
 426     }
 427
 428     bool IsKindOf(wxClassInfo *info) const;
 429
 430
 431     // Turn on the correct set of new and delete operators
 432
 433 #ifdef _WX_WANT_NEW_SIZET_WXCHAR_INT
 434     void *operator new ( size_t size, const wxChar *fileName = NULL, int lineNum = 0 );
 435 #endif
 436
 437 #ifdef _WX_WANT_DELETE_VOID
 438     void operator delete ( void * buf );
 439 #endif
 440
 441 #ifdef _WX_WANT_DELETE_VOID_CONSTCHAR_SIZET
 442     void operator delete ( void *buf, const char *_fname, size_t _line );
 443 #endif
 444
 445 #ifdef _WX_WANT_DELETE_VOID_WXCHAR_INT
 446     void operator delete ( void *buf, const wxChar*, int );
 447 #endif
 448
 449 #ifdef _WX_WANT_ARRAY_NEW_SIZET_WXCHAR_INT
 450     void *operator new[] ( size_t size, const wxChar *fileName = NULL, int lineNum = 0 );
 451 #endif
 452
 453 #ifdef _WX_WANT_ARRAY_DELETE_VOID
 454     void operator delete[] ( void *buf );
 455 #endif
 456
 457 #ifdef _WX_WANT_ARRAY_DELETE_VOID_WXCHAR_INT
 458     void operator delete[] (void* buf, const wxChar*, int );
 459 #endif
 460
 461
 462 #if wxUSE_STD_IOSTREAM && (defined(__WXDEBUG__) || wxUSE_DEBUG_CONTEXT)
 463     virtual void Dump(wxSTD ostream& str);
 464 #endif
 465
 466     // ref counted data handling methods
 467
 468     // get/set
 469     wxObjectRefData *GetRefData() const { return m_refData; }
 470     void SetRefData(wxObjectRefData *data) { m_refData = data; }
 471
 472     // make a 'clone' of the object
 473     void Ref(const wxObject& clone);
 474
 475     // destroy a reference
 476     void UnRef();
 477
 478 protected:
 479     // ensure that our data is not shared with anybody else: if we have no
 480     // data, it is created using CreateRefData() below, if we have shared data
 481     // it is copied using CloneRefData(), otherwise nothing is done
 482     void AllocExclusive();
 483
 484     // both methods must be implemented if Unshare() is used, not pure virtual
 485     // only because of the backwards compatibility reasons
 486
 487     // create a new m_refData
 488     virtual wxObjectRefData *CreateRefData() const;
 489
 490     // create a new m_refData initialized with the given one
 491     virtual wxObjectRefData *CloneRefData(const wxObjectRefData *data) const;
 492
 493     wxObjectRefData *m_refData;
 494 };
 495
 496 // ----------------------------------------------------------------------------
 497 // wxObjectRefData: ref counted data meant to be stored in wxObject
 498 // ----------------------------------------------------------------------------
 499
 500 class WXDLLEXPORT wxObjectRefData
 501 {
 502     friend class wxObject;
 503
 504 public:
 505     wxObjectRefData() : m_count(1) { }
 506     virtual ~wxObjectRefData() { }
 507
 508     int GetRefCount() const { return m_count; }
 509
 510 private:
 511     int m_count;
 512 };
 513
 514
 515 inline wxObject *wxCheckDynamicCast(wxObject *obj, wxClassInfo *classInfo)
 516 {
 517     return obj && obj->GetClassInfo()->IsKindOf(classInfo) ? obj : NULL;
 518 }
 519
 520 // ----------------------------------------------------------------------------
 521 // more debugging macros
 522 // ----------------------------------------------------------------------------
 523
 524 #ifdef __WXDEBUG__
 525     #ifndef WXDEBUG_NEW
 526         #define WXDEBUG_NEW new(__TFILE__,__LINE__)
 527     #endif
 528 #else // !__WXDEBUG__
 529     #define WXDEBUG_NEW new
 530 #endif
 531
 532 // Redefine new to be the debugging version. This doesn't work with all
 533 // compilers, in which case you need to use WXDEBUG_NEW explicitly if you wish
 534 // to use the debugging version.
 535
 536 #if defined(__WXDEBUG__) && wxUSE_GLOBAL_MEMORY_OPERATORS && wxUSE_DEBUG_NEW_ALWAYS
 537     #define new new(__TFILE__,__LINE__)
 538 #endif
 539
 540 #endif  // _WX_OBJECTH__
 541