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