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