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 WXDLLIMPEXP_BASE _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 WXDLLIMPEXP_BASE _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         return CreateNode( value  , bucket); \
 282     }\
 283     Node * CreateNode( const value_type& value, size_t bucket ) \
 284     {\
 285         Node* node = new Node( value ); \
 286         node->m_nxt = m_table[bucket]; \
 287         m_table[bucket] = node; \
 288  \
 289         /* must be after the node is inserted */ \
 290         ++m_items; \
 291         if( SHOULD_GROW( m_tableBuckets, m_items ) ) \
 292             ResizeTable( m_tableBuckets ); \
 293  \
 294         return node; \
 295     } \
 296     void CreateNode( const value_type& value ) \
 297     {\
 298         CreateNode(value, m_hasher( m_getKey(value) ) % m_tableBuckets ); \
 299     }\
 300  \
 301     /* returns NULL if not found */ \
 302     Node** GetNodePtr( const const_key_type& key ) const \
 303     { \
 304         unsigned long hash = m_hasher( key ); \
 305         Node** node = &m_table[hash % m_tableBuckets]; \
 306  \
 307         while( *node ) \
 308         { \
 309             if( m_equals( m_getKey( (*node)->m_value ), key ) ) \
 310                 return node; \
 311             node = (Node**)&(*node)->m_nxt; \
 312         } \
 313  \
 314         return 0; \
 315     } \
 316  \
 317     /* returns NULL if not found */ \
 318     /* expressing it in terms of GetNodePtr is 5-8% slower :-( */ \
 319     Node* GetNode( const const_key_type& key ) const \
 320     { \
 321         unsigned long hash = m_hasher( key ); \
 322         Node* node = m_table[hash % m_tableBuckets]; \
 323  \
 324         while( node ) \
 325         { \
 326             if( m_equals( m_getKey( node->m_value ), key ) ) \
 327                 return node; \
 328             node = node->m_next(); \
 329         } \
 330  \
 331         return 0; \
 332     } \
 333  \
 334     void ResizeTable( size_t newSize ) \
 335     { \
 336         newSize = GetNextPrime( (unsigned long)newSize ); \
 337         Node** srcTable = m_table; \
 338         size_t srcBuckets = m_tableBuckets; \
 339         m_table = (Node**)AllocTable( newSize ); \
 340         m_tableBuckets = newSize; \
 341  \
 342         CopyHashTable( (_wxHashTable_NodeBase**)srcTable, srcBuckets, \
 343                        this, (_wxHashTable_NodeBase**)m_table, \
 344                        (BucketFromNode)GetBucketForNode,\
 345                        (ProcessNode)&DummyProcessNode ); \
 346         free(srcTable); \
 347     } \
 348  \
 349     /* this must be called _after_ m_table has been cleaned */ \
 350     void HashCopy( const Self& ht ) \
 351     { \
 352         ResizeTable( ht.size() ); \
 353         CopyHashTable( (_wxHashTable_NodeBase**)ht.m_table, ht.m_tableBuckets,\
 354                        (_wxHashTableBase2*)this, \
 355                        (_wxHashTable_NodeBase**)m_table, \
 356                        (BucketFromNode)GetBucketForNode, \
 357                        (ProcessNode)CopyNode ); \
 358     } \
 359 };
 360
 361 // defines an STL-like pair class CLASSNAME storing two fields: first of type
 362 // KEY_T and second of type VALUE_T
 363 #define _WX_DECLARE_PAIR( KEY_T, VALUE_T, CLASSNAME, CLASSEXP ) \
 364 CLASSEXP CLASSNAME \
 365 { \
 366 public: \
 367     typedef KEY_T t1; \
 368     typedef VALUE_T t2; \
 369     typedef const KEY_T const_t1; \
 370     typedef const VALUE_T const_t2; \
 371  \
 372     CLASSNAME( const const_t1& f, const const_t2& s ):first(t1(f)),second(t2(s)) {} \
 373     CLASSNAME( const const_t1& f ):first(t1(f)),second(t2()) {} \
 374  \
 375     t1 first; \
 376     t2 second; \
 377 };
 378
 379 // defines the class CLASSNAME returning the key part (of type KEY_T) from a
 380 // pair of type PAIR_T
 381 #define _WX_DECLARE_HASH_MAP_KEY_EX( KEY_T, PAIR_T, CLASSNAME, CLASSEXP ) \
 382 CLASSEXP CLASSNAME \
 383 { \
 384     typedef KEY_T key_type; \
 385     typedef PAIR_T pair_type; \
 386     typedef const key_type const_key_type; \
 387     typedef const pair_type const_pair_type; \
 388     typedef const_key_type& const_key_reference; \
 389     typedef const_pair_type& const_pair_reference; \
 390 public: \
 391     CLASSNAME() { } \
 392     const_key_reference operator()( const_pair_reference pair ) const { return pair.first; }\
 393     \
 394     /* the dummy assignment operator is needed to suppress compiler */ \
 395     /* warnings from hash table class' operator=(): gcc complains about */ \
 396     /* "statement with no effect" without it */ \
 397     CLASSNAME& operator=(const CLASSNAME&) { return *this; } \
 398 };
 399
 400 // grow/shrink predicates
 401 inline bool never_grow( size_t, size_t ) { return FALSE; }
 402 inline bool never_shrink( size_t, size_t ) { return FALSE; }
 403 inline bool grow_lf70( size_t buckets, size_t items )
 404 {
 405     return float(items)/float(buckets) >= 0.85;
 406 }
 407
 408 // ----------------------------------------------------------------------------
 409 // hashing and comparison functors
 410 // ----------------------------------------------------------------------------
 411
 412 // NB: implementation detail: all of these classes must have dummy assignment
 413 //     operators to suppress warnings about "statement with no effect" from gcc
 414 //     in the hash table class assignment operator (where they're assigned)
 415
 416 // integer types
 417 class WXDLLIMPEXP_BASE wxIntegerHash
 418 {
 419 public:
 420     wxIntegerHash() { }
 421     unsigned long operator()( long x ) const { return (unsigned long)x; }
 422     unsigned long operator()( unsigned long x ) const { return x; }
 423     unsigned long operator()( int x ) const { return (unsigned long)x; }
 424     unsigned long operator()( unsigned int x ) const { return x; }
 425     unsigned long operator()( short x ) const { return (unsigned long)x; }
 426     unsigned long operator()( unsigned short x ) const { return x; }
 427
 428     wxIntegerHash& operator=(const wxIntegerHash&) { return *this; }
 429 };
 430
 431 class WXDLLIMPEXP_BASE wxIntegerEqual
 432 {
 433 public:
 434     wxIntegerEqual() { }
 435     bool operator()( long a, long b ) const { return a == b; }
 436     bool operator()( unsigned long a, unsigned long b ) const { return a == b; }
 437     bool operator()( int a, int b ) const { return a == b; }
 438     bool operator()( unsigned int a, unsigned int b ) const { return a == b; }
 439     bool operator()( short a, short b ) const { return a == b; }
 440     bool operator()( unsigned short a, unsigned short b ) const { return a == b; }
 441
 442     wxIntegerEqual& operator=(const wxIntegerEqual&) { return *this; }
 443 };
 444
 445 // pointers
 446 class WXDLLIMPEXP_BASE wxPointerHash
 447 {
 448 public:
 449     wxPointerHash() { }
 450
 451     // TODO: this might not work well on architectures with 64 bit pointers but
 452     //       32 bit longs, we should use % ULONG_MAX there
 453     unsigned long operator()( const void* k ) const { return (unsigned long)wxPtrToULong(k); }
 454
 455     wxPointerHash& operator=(const wxPointerHash&) { return *this; }
 456 };
 457
 458 class WXDLLIMPEXP_BASE wxPointerEqual
 459 {
 460 public:
 461     wxPointerEqual() { }
 462     bool operator()( const void* a, const void* b ) const { return a == b; }
 463
 464     wxPointerEqual& operator=(const wxPointerEqual&) { return *this; }
 465 };
 466
 467 // wxString, char*, wxChar*
 468 class WXDLLIMPEXP_BASE wxStringHash
 469 {
 470 public:
 471     wxStringHash() {}
 472     unsigned long operator()( const wxString& x ) const
 473         { return wxCharStringHash( x.c_str() ); }
 474     unsigned long operator()( const wxChar* x ) const
 475         { return wxCharStringHash( x ); }
 476     static unsigned long wxCharStringHash( const wxChar* );
 477 #if wxUSE_UNICODE
 478     unsigned long operator()( const char* x ) const
 479         { return charStringHash( x ); }
 480     static unsigned long charStringHash( const char* );
 481 #endif // wxUSE_UNICODE
 482
 483     wxStringHash& operator=(const wxStringHash&) { return *this; }
 484 };
 485
 486 class WXDLLIMPEXP_BASE wxStringEqual
 487 {
 488 public:
 489     wxStringEqual() {}
 490     bool operator()( const wxString& a, const wxString& b ) const
 491         { return a == b; }
 492     bool operator()( const wxChar* a, const wxChar* b ) const
 493         { return wxStrcmp( a, b ) == 0; }
 494 #if wxUSE_UNICODE
 495     bool operator()( const char* a, const char* b ) const
 496         { return strcmp( a, b ) == 0; }
 497 #endif // wxUSE_UNICODE
 498
 499     wxStringEqual& operator=(const wxStringEqual&) { return *this; }
 500 };
 501
 502 #define _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, CLASSEXP ) \
 503 _WX_DECLARE_PAIR( KEY_T, VALUE_T, CLASSNAME##_wxImplementation_Pair, CLASSEXP ) \
 504 _WX_DECLARE_HASH_MAP_KEY_EX( KEY_T, CLASSNAME##_wxImplementation_Pair, CLASSNAME##_wxImplementation_KeyEx, CLASSEXP ) \
 505 _WX_DECLARE_HASHTABLE( CLASSNAME##_wxImplementation_Pair, KEY_T, HASH_T, CLASSNAME##_wxImplementation_KeyEx, KEY_EQ_T, CLASSNAME##_wxImplementation_HashTable, CLASSEXP, grow_lf70, never_shrink ) \
 506 CLASSEXP CLASSNAME:public CLASSNAME##_wxImplementation_HashTable \
 507 { \
 508 public: \
 509     typedef VALUE_T mapped_type; \
 510  \
 511     CLASSNAME( size_type hint = 100, hasher hf = hasher(), key_equal eq = key_equal() ) \
 512         : CLASSNAME##_wxImplementation_HashTable( hint, hf, eq, CLASSNAME##_wxImplementation_KeyEx() ) {} \
 513  \
 514     mapped_type& operator[]( const const_key_type& key ) \
 515     { \
 516         return GetOrCreateNode( CLASSNAME##_wxImplementation_Pair( key ) )->m_value.second; \
 517     } \
 518  \
 519     const_iterator find( const const_key_type& key ) const \
 520     { \
 521         return const_iterator( GetNode( key ), this ); \
 522     } \
 523  \
 524     iterator find( const const_key_type& key ) \
 525     { \
 526         return iterator( GetNode( key ), this ); \
 527     } \
 528  \
 529     void insert( const value_type& v ) { (*this)[v.first] = v.second; } \
 530  \
 531     size_type erase( const key_type& k ) \
 532         { return CLASSNAME##_wxImplementation_HashTable::erase( k ); } \
 533     void erase( const iterator& it ) { erase( it->first ); } \
 534     void erase( const const_iterator& it ) { erase( it->first ); } \
 535  \
 536     /* count() == 0 | 1 */ \
 537     size_type count( const const_key_type& key ) \
 538         { return GetNode( key ) ? 1 : 0; } \
 539 }
 540
 541 // these macros are to be used in the user code
 542 #define WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME) \
 543     _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, class )
 544
 545 #define WX_DECLARE_STRING_HASH_MAP( VALUE_T, CLASSNAME ) \
 546     _WX_DECLARE_HASH_MAP( wxString, VALUE_T, wxStringHash, wxStringEqual, \
 547                           CLASSNAME, class )
 548
 549 #define WX_DECLARE_VOIDPTR_HASH_MAP( VALUE_T, CLASSNAME ) \
 550     _WX_DECLARE_HASH_MAP( void*, VALUE_T, wxPointerHash, wxPointerEqual, \
 551                           CLASSNAME, class )
 552
 553 // and these do exactly the same thing but should be used inside the
 554 // library
 555 #define WX_DECLARE_EXPORTED_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME) \
 556     _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, class WXDLLEXPORT )
 557
 558 #define WX_DECLARE_EXPORTED_STRING_HASH_MAP( VALUE_T, CLASSNAME ) \
 559     _WX_DECLARE_HASH_MAP( wxString, VALUE_T, wxStringHash, wxStringEqual, \
 560                           CLASSNAME, class WXDLLEXPORT )
 561
 562 #define WX_DECLARE_EXPORTED_VOIDPTR_HASH_MAP( VALUE_T, CLASSNAME ) \
 563     _WX_DECLARE_HASH_MAP( void*, VALUE_T, wxPointerHash, wxPointerEqual, \
 564                           CLASSNAME, class WXDLLEXPORT )
 565
 566 #endif // _WX_HASHMAP_H_
 567