include/wx/hash.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/hash.h
   3 // Purpose:     wxHashTable class
   4 // Author:      Julian Smart
   5 // Modified by: VZ at 25.02.00: type safe hashes with WX_DECLARE_HASH()
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c)
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_HASH_H__
  13 #define _WX_HASH_H__
  14
  15 #ifdef __GNUG__
  16 #pragma interface "hash.h"
  17 #endif
  18
  19 #include "wx/list.h"
  20 #include "wx/dynarray.h"
  21
  22 // the default size of the hash
  23 #define wxHASH_SIZE_DEFAULT     (1000)
  24
  25 /*
  26  * A hash table is an array of user-definable size with lists
  27  * of data items hanging off the array positions.  Usually there'll
  28  * be a hit, so no search is required; otherwise we'll have to run down
  29  * the list to find the desired item.
  30 */
  31
  32 // ----------------------------------------------------------------------------
  33 // this is the base class for object hashes: hash tables which contain
  34 // pointers to objects
  35 // ----------------------------------------------------------------------------
  36
  37 class WXDLLEXPORT wxHashTableBase : public wxObject
  38 {
  39 public:
  40     wxHashTableBase();
  41
  42     void Create(wxKeyType keyType = wxKEY_INTEGER,
  43                 size_t size = wxHASH_SIZE_DEFAULT);
  44     void Destroy();
  45
  46     size_t GetSize() const { return m_hashSize; }
  47     size_t GetCount() const { return m_count; }
  48
  49     void DeleteContents(bool flag);
  50
  51 protected:
  52     // find the node for (key, value)
  53     wxNodeBase *GetNode(long key, long value) const;
  54
  55     // the array of lists in which we store the values for given key hash
  56     wxListBase **m_hashTable;
  57
  58     // the size of m_lists array
  59     size_t m_hashSize;
  60
  61     // the type of indexing we use
  62     wxKeyType m_keyType;
  63
  64     // the total number of elements in the hash
  65     size_t m_count;
  66
  67     // should we delete our data?
  68     bool m_deleteContents;
  69
  70 private:
  71     // no copy ctor/assignment operator (yet)
  72     DECLARE_NO_COPY_CLASS(wxHashTableBase);
  73 };
  74
  75 // ----------------------------------------------------------------------------
  76 // a hash table which stores longs
  77 // ----------------------------------------------------------------------------
  78
  79 class WXDLLEXPORT wxHashTableLong : public wxObject
  80 {
  81 public:
  82     wxHashTableLong(size_t size = wxHASH_SIZE_DEFAULT) { Init(size); }
  83
  84     void Create(size_t size = wxHASH_SIZE_DEFAULT);
  85     void Destroy();
  86
  87     size_t GetSize() const { return m_hashSize; }
  88     size_t GetCount() const { return m_count; }
  89
  90     void Put(long key, long value);
  91     long Get(long key) const;
  92     long Delete(long key);
  93
  94 protected:
  95     void Init(size_t size);
  96
  97 private:
  98     wxArrayLong **m_values,
  99                 **m_keys;
 100
 101     // the size of array above
 102     size_t m_hashSize;
 103
 104     // the total number of elements in the hash
 105     size_t m_count;
 106
 107     // not implemented yet
 108     DECLARE_NO_COPY_CLASS(wxHashTableLong);
 109 };
 110
 111 // ----------------------------------------------------------------------------
 112 // for compatibility only
 113 // ----------------------------------------------------------------------------
 114
 115 class WXDLLEXPORT wxHashTable : public wxObject
 116 {
 117 public:
 118     int n;
 119     int current_position;
 120     wxNode *current_node;
 121
 122     unsigned int key_type;
 123     wxList **hash_table;
 124
 125     wxHashTable(int the_key_type = wxKEY_INTEGER,
 126                 int size = wxHASH_SIZE_DEFAULT);
 127     ~wxHashTable();
 128
 129     // copy ctor and assignment operator
 130     wxHashTable(const wxHashTable& table) { DoCopy(table); }
 131     wxHashTable& operator=(const wxHashTable& table)
 132         { Clear(); DoCopy(table); return *this; }
 133
 134     void DoCopy(const wxHashTable& table);
 135
 136     void Destroy();
 137
 138     bool Create(int the_key_type = wxKEY_INTEGER,
 139                 int size = wxHASH_SIZE_DEFAULT);
 140
 141     // Note that there are 2 forms of Put, Get.
 142     // With a key and a value, the *value* will be checked
 143     // when a collision is detected. Otherwise, if there are
 144     // 2 items with a different value but the same key,
 145     // we'll retrieve the WRONG ONE. So where possible,
 146     // supply the required value along with the key.
 147     // In fact, the value-only versions make a key, and still store
 148     // the value. The use of an explicit key might be required
 149     // e.g. when combining several values into one key.
 150     // When doing that, it's highly likely we'll get a collision,
 151     // e.g. 1 + 2 = 3, 2 + 1 = 3.
 152
 153     // key and value are NOT necessarily the same
 154     void Put(long key, long value, wxObject *object);
 155     void Put(long key, const wxChar *value, wxObject *object);
 156
 157     // key and value are the same
 158     void Put(long value, wxObject *object);
 159     void Put(const wxChar *value, wxObject *object);
 160
 161     // key and value not the same
 162     wxObject *Get(long key, long value) const;
 163     wxObject *Get(long key, const wxChar *value) const;
 164
 165     // key and value are the same
 166     wxObject *Get(long value) const;
 167     wxObject *Get(const wxChar *value) const;
 168
 169     // Deletes entry and returns data if found
 170     wxObject *Delete(long key);
 171     wxObject *Delete(const wxChar *key);
 172
 173     wxObject *Delete(long key, int value);
 174     wxObject *Delete(long key, const wxChar *value);
 175
 176     // Construct your own integer key from a string, e.g. in case
 177     // you need to combine it with something
 178     long MakeKey(const wxChar *string) const;
 179
 180     // Way of iterating through whole hash table (e.g. to delete everything)
 181     // Not necessary, of course, if you're only storing pointers to
 182     // objects maintained separately
 183
 184     void BeginFind();
 185     wxNode *Next();
 186
 187     void DeleteContents(bool flag);
 188     void Clear();
 189
 190     // Returns number of nodes
 191     size_t GetCount() const { return m_count; }
 192
 193 private:
 194     size_t m_count;             // number of elements in the hashtable
 195     bool m_deleteContents;
 196
 197     DECLARE_DYNAMIC_CLASS(wxHashTable)
 198 };
 199
 200 // defines a new type safe hash table which stores the elements of type eltype
 201 // in lists of class listclass
 202 #define WX_DECLARE_HASH(eltype, listclass, hashclass)                          \
 203     class WXDLLEXPORT hashclass : public wxHashTableBase                       \
 204     {                                                                          \
 205     public:                                                                    \
 206         hashclass(wxKeyType keyType = wxKEY_INTEGER,                           \
 207                   size_t size = wxHASH_SIZE_DEFAULT)                           \
 208             { Create(keyType, size); }                                         \
 209                                                                                \
 210         ~hashclass() { Destroy(); }                                            \
 211                                                                                \
 212         void Put(long key, long val, eltype *data) { DoPut(key, val, data); }  \
 213         void Put(long key, eltype *data) { DoPut(key, key, data); }            \
 214                                                                                \
 215         eltype *Get(long key, long value) const                                \
 216         {                                                                      \
 217             wxNodeBase *node = GetNode(key, value);                            \
 218             return node ? ((listclass::Node *)node)->GetData() : (eltype *)0;  \
 219         }                                                                      \
 220         eltype *Get(long key) const { return Get(key, key); }                  \
 221                                                                                \
 222         eltype *Delete(long key, long value)                                   \
 223         {                                                                      \
 224             eltype *data;                                                      \
 225                                                                                \
 226             wxNodeBase *node = GetNode(key, value);                            \
 227             if ( node )                                                        \
 228             {                                                                  \
 229                 data = ((listclass::Node *)node)->GetData();                   \
 230                                                                                \
 231                 delete node;                                                   \
 232                 m_count--;                                                     \
 233             }                                                                  \
 234             else                                                               \
 235             {                                                                  \
 236                 data = (eltype *)0;                                            \
 237             }                                                                  \
 238                                                                                \
 239             return data;                                                       \
 240         }                                                                      \
 241         eltype *Delete(long key) { return Delete(key, key); }                  \
 242                                                                                \
 243     protected:                                                                 \
 244         void DoPut(long key, long value, eltype *data)                         \
 245         {                                                                      \
 246             size_t slot = (size_t)abs(key % m_hashSize);                       \
 247                                                                                \
 248             if ( !m_hashTable[slot] )                                          \
 249             {                                                                  \
 250                 m_hashTable[slot] = new listclass(m_keyType);                  \
 251                 if ( m_deleteContents )                                        \
 252                     m_hashTable[slot]->DeleteContents(TRUE);                   \
 253             }                                                                  \
 254                                                                                \
 255             ((listclass *)m_hashTable[slot])->Append(value, data);             \
 256             m_count++;                                                         \
 257         }                                                                      \
 258     }
 259
 260 #endif
 261     // _WX_HASH_H__