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