include/wx/hashmap.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        hashmap.h
   3 // Purpose:     wxHashMap class
   4 // Author:      Mattia Barbon
   5 // Modified by:
   6 // Created:     29/01/2002
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Mattia Barbon
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_HASHMAP_H_
  13 #define _WX_HASHMAP_H_
  14
  15 #if defined(__GNUG__) && !defined(__APPLE__)
  16 #pragma interface "hashmap.h"
  17 #endif
  18
  19 #include "wx/string.h"
  20
  21 #include <stddef.h>             // for ptrdiff_t
  22
  23 #ifdef __WXWINCE__
  24 typedef int ptrdiff_t;
  25 #endif
  26
  27 // private
  28 struct WXDLLIMPEXP_BASE _wxHashTable_NodeBase
  29 {
  30     _wxHashTable_NodeBase() : m_nxt(0) {}
  31
  32     _wxHashTable_NodeBase* m_nxt;
  33
  34 // Cannot do this:
  35 //  DECLARE_NO_COPY_CLASS(_wxHashTable_NodeBase)
  36 // without rewriting the macros, which require a public copy constructor.
  37 };
  38
  39 // private
  40 class WXDLLIMPEXP_BASE _wxHashTableBase2
  41 {
  42 public:
  43     typedef void (*NodeDtor)(_wxHashTable_NodeBase*);
  44     typedef unsigned long (*BucketFromNode)(_wxHashTableBase2*,_wxHashTable_NodeBase*);
  45     typedef _wxHashTable_NodeBase* (*ProcessNode)(_wxHashTable_NodeBase*);
  46 protected:
  47     static _wxHashTable_NodeBase* DummyProcessNode(_wxHashTable_NodeBase* node);
  48     static void DeleteNodes( size_t buckets, _wxHashTable_NodeBase** table,
  49                              NodeDtor dtor );
  50     static _wxHashTable_NodeBase* GetFirstNode( size_t buckets,
  51                                                 _wxHashTable_NodeBase** table )
  52     {
  53         for( size_t i = 0; i < buckets; ++i )
  54             if( table[i] )
  55                 return table[i];
  56         return 0;
  57     }
  58
  59     // as static const unsigned prime_count = 31 but works with all compilers
  60     enum { prime_count = 31 };
  61     static const unsigned long ms_primes[prime_count];
  62
  63     // returns the first prime in ms_primes greater than n
  64     static unsigned long GetNextPrime( unsigned long n );
  65
  66     // returns the first prime in ms_primes smaller than n
  67     // ( or ms_primes[0] if n is very small )
  68     static unsigned long GetPreviousPrime( unsigned long n );
  69
  70     static void CopyHashTable( _wxHashTable_NodeBase** srcTable,
  71                                size_t srcBuckets, _wxHashTableBase2* dst,
  72                                _wxHashTable_NodeBase** dstTable,
  73                                BucketFromNode func, ProcessNode proc );
  74
  75     static void** AllocTable( size_t sz )
  76     {
  77 #ifdef __WXWINCE__
  78         return (void **)malloc(sz * sizeof(void*));
  79 #else
  80         return (void **)calloc(sz, sizeof(void*));
  81 #endif
  82     }
  83 };
  84
  85 #define _WX_DECLARE_HASHTABLE( VALUE_T, KEY_T, HASH_T, KEY_EX_T, KEY_EQ_T, CLASSNAME, CLASSEXP, SHOULD_GROW, SHOULD_SHRINK ) \
  86 CLASSEXP CLASSNAME : protected _wxHashTableBase2 \
  87 { \
  88 public: \
  89     typedef KEY_T key_type; \
  90     typedef VALUE_T value_type; \
  91     typedef HASH_T hasher; \
  92     typedef KEY_EQ_T key_equal; \
  93  \
  94     typedef size_t size_type; \
  95     typedef ptrdiff_t difference_type; \
  96     typedef value_type* pointer; \
  97     typedef const value_type* const_pointer; \
  98     typedef value_type& reference; \
  99     typedef const value_type& const_reference; \
 100     /* should these be protected? */ \
 101     typedef const KEY_T const_key_type; \
 102     typedef const VALUE_T const_mapped_type; \
 103 public: \
 104     struct Node; \
 105     typedef KEY_EX_T key_extractor; \
 106     typedef CLASSNAME Self; \
 107 protected: \
 108     Node** m_table; \
 109     size_t m_tableBuckets; \
 110     size_t m_items; \
 111     hasher m_hasher; \
 112     key_equal m_equals; \
 113     key_extractor m_getKey; \
 114 public: \
 115     struct Node:public _wxHashTable_NodeBase \
 116     { \
 117     public: \
 118         Node( const value_type& value ) \
 119             : m_value( value ) {} \
 120         Node* m_next() { return (Node*)this->m_nxt; } \
 121  \
 122         value_type m_value; \
 123     }; \
 124  \
 125     struct Iterator; \
 126     friend struct Iterator; \
 127 protected: \
 128     static void DeleteNode( _wxHashTable_NodeBase* node ) \
 129     { \
 130         delete (Node*)node; \
 131     } \
 132 public: \
 133     /*                  */ \
 134     /* forward iterator */ \
 135     /*                  */ \
 136     struct Iterator \
 137     { \
 138         Node* m_node; \
 139         Self* m_ht; \
 140  \
 141         Iterator() : m_node(0), m_ht(0) {} \
 142         Iterator( Node* node, const Self* ht ) \
 143             : m_node(node), m_ht((Self*)ht) {} \
 144         bool operator ==( const Iterator& it ) const \
 145             { return m_node == it.m_node; } \
 146         bool operator !=( const Iterator& it ) const \
 147             { return m_node != it.m_node; } \
 148     protected: \
 149         Node* GetNextNode() \
 150         { \
 151             size_type bucket = GetBucketForNode(m_ht,m_node); \
 152             for( size_type i = bucket + 1; i < m_ht->m_tableBuckets; ++i ) \
 153             { \
 154                 if( m_ht->m_table[i] ) \
 155                     return m_ht->m_table[i]; \
 156             } \
 157             return 0; \
 158         } \
 159  \
 160         void PlusPlus() \
 161         { \
 162             Node* next = m_node->m_next(); \
 163             m_node = next ? next : GetNextNode(); \
 164         } \
 165     }; \
 166  \
 167 public: \
 168     struct iterator:public Iterator \
 169     { \
 170         iterator() : Iterator() {} \
 171         iterator( Node* node, Self* ht ) : Iterator( node, ht ) {} \
 172         iterator& operator++() { PlusPlus(); return *this; } \
 173         iterator operator++(int) { iterator it=*this;PlusPlus();return it; } \
 174         reference operator *() const { return m_node->m_value; } \
 175         pointer operator ->() const { return &(m_node->m_value); } \
 176     }; \
 177  \
 178     struct const_iterator:public Iterator \
 179     { \
 180         const_iterator() : Iterator() {} \
 181         const_iterator( Node* node, const Self* ht ) \
 182             : Iterator( node, (Self*)ht ) {} \
 183         const_iterator& operator++() { PlusPlus();return *this; } \
 184         const_iterator operator++(int) { const_iterator it=*this;PlusPlus();return it; } \
 185         const_reference operator *() const { return m_node->m_value; } \
 186         const_pointer operator ->() const { return &(m_node->m_value); } \
 187     }; \
 188  \
 189     CLASSNAME( size_type sz = 10, const hasher& hfun = hasher(), \
 190                const key_equal& k_eq = key_equal(), \
 191                const key_extractor& k_ex = key_extractor() ) \
 192         : m_tableBuckets( GetNextPrime( (unsigned long) sz ) ), \
 193           m_items( 0 ), \
 194           m_hasher( hfun ), \
 195           m_equals( k_eq ), \
 196           m_getKey( k_ex ) \
 197     { \
 198         m_table = (Node**)AllocTable( m_tableBuckets ); \
 199     } \
 200  \
 201     CLASSNAME( const Self& ht ) \
 202         : m_table( 0 ), \
 203           m_tableBuckets( 0 ), \
 204           m_items( ht.m_items ), \
 205           m_hasher( ht.m_hasher ), \
 206           m_equals( ht.m_equals ), \
 207           m_getKey( ht.m_getKey ) \
 208     { \
 209         HashCopy( ht ); \
 210     } \
 211  \
 212     const Self& operator=( const Self& ht ) \
 213     { \
 214          clear(); \
 215          m_hasher = ht.m_hasher; \
 216          m_equals = ht.m_equals; \
 217          m_getKey = ht.m_getKey; \
 218          m_items = ht.m_items; \
 219          HashCopy( ht ); \
 220          return *this; \
 221     } \
 222  \
 223     ~CLASSNAME() \
 224     { \
 225         clear(); \
 226  \
 227         free(m_table); \
 228     } \
 229  \
 230     hasher hash_funct() { return m_hasher; } \
 231     key_equal key_eq() { return m_equals; } \
 232  \
 233     /* removes all elements from the hash table, but does not */ \
 234     /* shrink it ( perhaps it should ) */ \
 235     void clear() \
 236     { \
 237         DeleteNodes( m_tableBuckets, (_wxHashTable_NodeBase**)m_table, \
 238                      DeleteNode ); \
 239         m_items = 0; \
 240     } \
 241  \
 242     size_type size() const { return m_items; } \
 243     size_type max_size() const { return size_type(-1); } \
 244     bool empty() const { return size() == 0; } \
 245  \
 246     const_iterator end() const { return const_iterator( 0, this ); } \
 247     iterator end() { return iterator( 0, this ); } \
 248     const_iterator begin() const \
 249         { return const_iterator( (Node*)GetFirstNode( m_tableBuckets, (_wxHashTable_NodeBase**)m_table ), this ); }; \
 250     iterator begin() \
 251         { return iterator( (Node*)GetFirstNode( m_tableBuckets, (_wxHashTable_NodeBase**)m_table ), this ); }; \
 252  \
 253     size_type erase( const const_key_type& key ) \
 254     { \
 255         Node** node = GetNodePtr( key ); \
 256  \
 257         if( !node ) \
 258             return 0; \
 259  \
 260         --m_items; \
 261         Node* temp = (*node)->m_next(); \
 262         delete *node; \
 263         (*node) = temp; \
 264         if( SHOULD_SHRINK( m_tableBuckets, m_items ) ) \
 265             ResizeTable( GetPreviousPrime( (unsigned long) m_tableBuckets ) - 1 ); \
 266         return 1; \
 267     } \
 268  \
 269 protected: \
 270     static size_type GetBucketForNode( Self* ht, Node* node ) \
 271     { \
 272         return ht->m_hasher( ht->m_getKey( node->m_value ) ) \
 273             % ht->m_tableBuckets; \
 274     } \
 275     static Node* CopyNode( Node* node ) { return new Node( *node ); } \
 276  \
 277     Node* GetOrCreateNode( const value_type& value ) \
 278     { \
 279         const const_key_type& key = m_getKey( value ); \
 280         size_t bucket = m_hasher( key ) % m_tableBuckets; \
 281         Node* node = m_table[bucket]; \
 282  \
 283         while( node ) \
 284         { \
 285             if( m_equals( m_getKey( node->m_value ), key ) ) \
 286                 return node; \
 287             node = node->m_next(); \
 288         } \
 289         return CreateNode( value  , bucket); \
 290     }\
 291     Node * CreateNode( const value_type& value, size_t bucket ) \
 292     {\
 293         Node* node = new Node( value ); \
 294         node->m_nxt = m_table[bucket]; \
 295         m_table[bucket] = node; \
 296  \
 297         /* must be after the node is inserted */ \
 298         ++m_items; \
 299         if( SHOULD_GROW( m_tableBuckets, m_items ) ) \
 300             ResizeTable( m_tableBuckets ); \
 301  \
 302         return node; \
 303     } \
 304     void CreateNode( const value_type& value ) \
 305     {\
 306         CreateNode(value, m_hasher( m_getKey(value) ) % m_tableBuckets ); \
 307     }\
 308  \
 309     /* returns NULL if not found */ \
 310     Node** GetNodePtr( const const_key_type& key ) const \
 311     { \
 312         unsigned long hash = m_hasher( key ); \
 313         Node** node = &m_table[hash % m_tableBuckets]; \
 314  \
 315         while( *node ) \
 316         { \
 317             if( m_equals( m_getKey( (*node)->m_value ), key ) ) \
 318                 return node; \
 319             node = (Node**)&(*node)->m_nxt; \
 320         } \
 321  \
 322         return 0; \
 323     } \
 324  \
 325     /* returns NULL if not found */ \
 326     /* expressing it in terms of GetNodePtr is 5-8% slower :-( */ \
 327     Node* GetNode( const const_key_type& key ) const \
 328     { \
 329         unsigned long hash = m_hasher( key ); \
 330         Node* node = m_table[hash % m_tableBuckets]; \
 331  \
 332         while( node ) \
 333         { \
 334             if( m_equals( m_getKey( node->m_value ), key ) ) \
 335                 return node; \
 336             node = node->m_next(); \
 337         } \
 338  \
 339         return 0; \
 340     } \
 341  \
 342     void ResizeTable( size_t newSize ) \
 343     { \
 344         newSize = GetNextPrime( (unsigned long)newSize ); \
 345         Node** srcTable = m_table; \
 346         size_t srcBuckets = m_tableBuckets; \
 347         m_table = (Node**)AllocTable( newSize ); \
 348         m_tableBuckets = newSize; \
 349  \
 350         CopyHashTable( (_wxHashTable_NodeBase**)srcTable, srcBuckets, \
 351                        this, (_wxHashTable_NodeBase**)m_table, \
 352                        (BucketFromNode)GetBucketForNode,\
 353                        (ProcessNode)&DummyProcessNode ); \
 354         free(srcTable); \
 355     } \
 356  \
 357     /* this must be called _after_ m_table has been cleaned */ \
 358     void HashCopy( const Self& ht ) \
 359     { \
 360         ResizeTable( ht.size() ); \
 361         CopyHashTable( (_wxHashTable_NodeBase**)ht.m_table, ht.m_tableBuckets,\
 362                        (_wxHashTableBase2*)this, \
 363                        (_wxHashTable_NodeBase**)m_table, \
 364                        (BucketFromNode)GetBucketForNode, \
 365                        (ProcessNode)CopyNode ); \
 366     } \
 367 };
 368
 369 // defines an STL-like pair class CLASSNAME storing two fields: first of type
 370 // KEY_T and second of type VALUE_T
 371 #define _WX_DECLARE_PAIR( KEY_T, VALUE_T, CLASSNAME, CLASSEXP ) \
 372 CLASSEXP CLASSNAME \
 373 { \
 374 public: \
 375     typedef KEY_T t1; \
 376     typedef VALUE_T t2; \
 377     typedef const KEY_T const_t1; \
 378     typedef const VALUE_T const_t2; \
 379  \
 380     CLASSNAME( const const_t1& f, const const_t2& s ):first(t1(f)),second(t2(s)) {} \
 381     CLASSNAME( const const_t1& f ):first(t1(f)),second(t2()) {} \
 382  \
 383     t1 first; \
 384     t2 second; \
 385 };
 386
 387 // defines the class CLASSNAME returning the key part (of type KEY_T) from a
 388 // pair of type PAIR_T
 389 #define _WX_DECLARE_HASH_MAP_KEY_EX( KEY_T, PAIR_T, CLASSNAME, CLASSEXP ) \
 390 CLASSEXP CLASSNAME \
 391 { \
 392     typedef KEY_T key_type; \
 393     typedef PAIR_T pair_type; \
 394     typedef const key_type const_key_type; \
 395     typedef const pair_type const_pair_type; \
 396     typedef const_key_type& const_key_reference; \
 397     typedef const_pair_type& const_pair_reference; \
 398 public: \
 399     CLASSNAME() { } \
 400     const_key_reference operator()( const_pair_reference pair ) const { return pair.first; }\
 401     \
 402     /* the dummy assignment operator is needed to suppress compiler */ \
 403     /* warnings from hash table class' operator=(): gcc complains about */ \
 404     /* "statement with no effect" without it */ \
 405     CLASSNAME& operator=(const CLASSNAME&) { return *this; } \
 406 };
 407
 408 // grow/shrink predicates
 409 inline bool never_grow( size_t, size_t ) { return FALSE; }
 410 inline bool never_shrink( size_t, size_t ) { return FALSE; }
 411 inline bool grow_lf70( size_t buckets, size_t items )
 412 {
 413     return float(items)/float(buckets) >= 0.85;
 414 }
 415
 416 // ----------------------------------------------------------------------------
 417 // hashing and comparison functors
 418 // ----------------------------------------------------------------------------
 419
 420 // NB: implementation detail: all of these classes must have dummy assignment
 421 //     operators to suppress warnings about "statement with no effect" from gcc
 422 //     in the hash table class assignment operator (where they're assigned)
 423
 424 // integer types
 425 class WXDLLIMPEXP_BASE wxIntegerHash
 426 {
 427 public:
 428     wxIntegerHash() { }
 429     unsigned long operator()( long x ) const { return (unsigned long)x; }
 430     unsigned long operator()( unsigned long x ) const { return x; }
 431     unsigned long operator()( int x ) const { return (unsigned long)x; }
 432     unsigned long operator()( unsigned int x ) const { return x; }
 433     unsigned long operator()( short x ) const { return (unsigned long)x; }
 434     unsigned long operator()( unsigned short x ) const { return x; }
 435
 436     wxIntegerHash& operator=(const wxIntegerHash&) { return *this; }
 437 };
 438
 439 class WXDLLIMPEXP_BASE wxIntegerEqual
 440 {
 441 public:
 442     wxIntegerEqual() { }
 443     bool operator()( long a, long b ) const { return a == b; }
 444     bool operator()( unsigned long a, unsigned long b ) const { return a == b; }
 445     bool operator()( int a, int b ) const { return a == b; }
 446     bool operator()( unsigned int a, unsigned int b ) const { return a == b; }
 447     bool operator()( short a, short b ) const { return a == b; }
 448     bool operator()( unsigned short a, unsigned short b ) const { return a == b; }
 449
 450     wxIntegerEqual& operator=(const wxIntegerEqual&) { return *this; }
 451 };
 452
 453 // pointers
 454 class WXDLLIMPEXP_BASE wxPointerHash
 455 {
 456 public:
 457     wxPointerHash() { }
 458
 459     // TODO: this might not work well on architectures with 64 bit pointers but
 460     //       32 bit longs, we should use % ULONG_MAX there
 461     unsigned long operator()( const void* k ) const { return (unsigned long)wxPtrToULong(k); }
 462
 463     wxPointerHash& operator=(const wxPointerHash&) { return *this; }
 464 };
 465
 466 class WXDLLIMPEXP_BASE wxPointerEqual
 467 {
 468 public:
 469     wxPointerEqual() { }
 470     bool operator()( const void* a, const void* b ) const { return a == b; }
 471
 472     wxPointerEqual& operator=(const wxPointerEqual&) { return *this; }
 473 };
 474
 475 // wxString, char*, wxChar*
 476 class WXDLLIMPEXP_BASE wxStringHash
 477 {
 478 public:
 479     wxStringHash() {}
 480     unsigned long operator()( const wxString& x ) const
 481         { return wxCharStringHash( x.c_str() ); }
 482     unsigned long operator()( const wxChar* x ) const
 483         { return wxCharStringHash( x ); }
 484     static unsigned long wxCharStringHash( const wxChar* );
 485 #if wxUSE_UNICODE
 486     unsigned long operator()( const char* x ) const
 487         { return charStringHash( x ); }
 488     static unsigned long charStringHash( const char* );
 489 #endif // wxUSE_UNICODE
 490
 491     wxStringHash& operator=(const wxStringHash&) { return *this; }
 492 };
 493
 494 class WXDLLIMPEXP_BASE wxStringEqual
 495 {
 496 public:
 497     wxStringEqual() {}
 498     bool operator()( const wxString& a, const wxString& b ) const
 499         { return a == b; }
 500     bool operator()( const wxChar* a, const wxChar* b ) const
 501         { return wxStrcmp( a, b ) == 0; }
 502 #if wxUSE_UNICODE
 503     bool operator()( const char* a, const char* b ) const
 504         { return strcmp( a, b ) == 0; }
 505 #endif // wxUSE_UNICODE
 506
 507     wxStringEqual& operator=(const wxStringEqual&) { return *this; }
 508 };
 509
 510 #define _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, CLASSEXP ) \
 511 _WX_DECLARE_PAIR( KEY_T, VALUE_T, CLASSNAME##_wxImplementation_Pair, CLASSEXP ) \
 512 _WX_DECLARE_HASH_MAP_KEY_EX( KEY_T, CLASSNAME##_wxImplementation_Pair, CLASSNAME##_wxImplementation_KeyEx, CLASSEXP ) \
 513 _WX_DECLARE_HASHTABLE( CLASSNAME##_wxImplementation_Pair, KEY_T, HASH_T, CLASSNAME##_wxImplementation_KeyEx, KEY_EQ_T, CLASSNAME##_wxImplementation_HashTable, CLASSEXP, grow_lf70, never_shrink ) \
 514 CLASSEXP CLASSNAME:public CLASSNAME##_wxImplementation_HashTable \
 515 { \
 516 public: \
 517     typedef VALUE_T mapped_type; \
 518  \
 519     CLASSNAME( size_type hint = 100, hasher hf = hasher(), key_equal eq = key_equal() ) \
 520         : CLASSNAME##_wxImplementation_HashTable( hint, hf, eq, CLASSNAME##_wxImplementation_KeyEx() ) {} \
 521  \
 522     mapped_type& operator[]( const const_key_type& key ) \
 523     { \
 524         return GetOrCreateNode( CLASSNAME##_wxImplementation_Pair( key ) )->m_value.second; \
 525     } \
 526  \
 527     const_iterator find( const const_key_type& key ) const \
 528     { \
 529         return const_iterator( GetNode( key ), this ); \
 530     } \
 531  \
 532     iterator find( const const_key_type& key ) \
 533     { \
 534         return iterator( GetNode( key ), this ); \
 535     } \
 536  \
 537     void insert( const value_type& v ) { (*this)[v.first] = v.second; } \
 538  \
 539     size_type erase( const key_type& k ) \
 540         { return CLASSNAME##_wxImplementation_HashTable::erase( k ); } \
 541     void erase( const iterator& it ) { erase( it->first ); } \
 542     void erase( const const_iterator& it ) { erase( it->first ); } \
 543  \
 544     /* count() == 0 | 1 */ \
 545     size_type count( const const_key_type& key ) \
 546         { return GetNode( key ) ? 1 : 0; } \
 547 }
 548
 549 // these macros are to be used in the user code
 550 #define WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME) \
 551     _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, class )
 552
 553 #define WX_DECLARE_STRING_HASH_MAP( VALUE_T, CLASSNAME ) \
 554     _WX_DECLARE_HASH_MAP( wxString, VALUE_T, wxStringHash, wxStringEqual, \
 555                           CLASSNAME, class )
 556
 557 #define WX_DECLARE_VOIDPTR_HASH_MAP( VALUE_T, CLASSNAME ) \
 558     _WX_DECLARE_HASH_MAP( void*, VALUE_T, wxPointerHash, wxPointerEqual, \
 559                           CLASSNAME, class )
 560
 561 // and these do exactly the same thing but should be used inside the
 562 // library
 563 #define WX_DECLARE_EXPORTED_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME) \
 564     _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, class WXDLLEXPORT )
 565
 566 #define WX_DECLARE_EXPORTED_STRING_HASH_MAP( VALUE_T, CLASSNAME ) \
 567     _WX_DECLARE_HASH_MAP( wxString, VALUE_T, wxStringHash, wxStringEqual, \
 568                           CLASSNAME, class WXDLLEXPORT )
 569
 570 #define WX_DECLARE_EXPORTED_VOIDPTR_HASH_MAP( VALUE_T, CLASSNAME ) \
 571     _WX_DECLARE_HASH_MAP( void*, VALUE_T, wxPointerHash, wxPointerEqual, \
 572                           CLASSNAME, class WXDLLEXPORT )
 573
 574 // delete all hash elements
 575 //
 576 // NB: the class declaration of the hash elements must be visible from the
 577 //     place where you use this macro, otherwise the proper destructor may not
 578 //     be called (a decent compiler should give a warning about it, but don't
 579 //     count on it)!
 580 #define WX_CLEAR_HASH_MAP(type, hashmap)                                     \
 581     {                                                                        \
 582         type::iterator it, en;                                               \
 583         for( it = (hashmap).begin(), en = (hashmap).end(); it != en; ++it )  \
 584             delete it->second;                                               \
 585         (hashmap).clear();                                                   \
 586     }
 587
 588 #endif // _WX_HASHMAP_H_
 589