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