src/Collections/hashset.h

   1 /*      Copyright (c) 2015 Regents of the University of California
   2  *
   3  *      Author: Brian Demsky <bdemsky@uci.edu>
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      version 2 as published by the Free Software Foundation.
   8  */
   9
  10 #ifndef HASHSET_H
  11 #define HASHSET_H
  12 #include "hashtable.h"
  13
  14 template<typename _Key>
  15 struct Linknode {
  16         _Key key;
  17         Linknode<_Key> *prev;
  18         Linknode<_Key> *next;
  19 };
  20
  21 template<typename _Key, typename _KeyInt, int _Shift, unsigned int (*hash_function)(_Key), bool (*equals)(_Key, _Key)>
  22 class Hashset;
  23
  24 template<typename _Key, typename _KeyInt, int _Shift, unsigned int (*hash_function)(_Key) = defaultHashFunction<_Key, _Shift, _KeyInt>, bool (*equals)(_Key, _Key) = defaultEquals<_Key> >
  25 class SetIterator {
  26 public:
  27         SetIterator(Linknode<_Key> *_curr, Hashset <_Key, _KeyInt, _Shift, hash_function, equals> *_set) :
  28                 curr(_curr),
  29                 set(_set)
  30         {
  31         }
  32
  33         /** Override: new operator */
  34         void *operator new(size_t size) {
  35                 return ourmalloc(size);
  36         }
  37
  38         /** Override: delete operator */
  39         void operator delete(void *p, size_t size) {
  40                 ourfree(p);
  41         }
  42
  43         /** Override: new[] operator */
  44         void *operator new[](size_t size) {
  45                 return ourmalloc(size);
  46         }
  47
  48         /** Override: delete[] operator */
  49         void operator delete[](void *p, size_t size) {
  50                 ourfree(p);
  51         }
  52
  53         bool hasNext() {
  54                 return curr != NULL;
  55         }
  56
  57         _Key next() {
  58                 _Key k = curr->key;
  59                 last = curr;
  60                 curr = curr->next;
  61                 return k;
  62         }
  63
  64         _Key currKey() {
  65                 return last->key;
  66         }
  67
  68         void remove() {
  69                 _Key k = last->key;
  70                 set->remove(k);
  71         }
  72
  73 private:
  74         Linknode<_Key> *curr;
  75         Linknode<_Key> *last;
  76         Hashset <_Key, _KeyInt, _Shift, hash_function, equals> *set;
  77 };
  78
  79 template<typename _Key, typename _KeyInt, int _Shift = 0, unsigned int (*hash_function)(_Key) = defaultHashFunction<_Key, _Shift, _KeyInt>, bool (*equals)(_Key, _Key) = defaultEquals<_Key> >
  80 class Hashset {
  81 public:
  82         Hashset(unsigned int initialcapacity = 16, double factor = 0.5) :
  83                 table(new Hashtable<_Key, Linknode<_Key> *, _KeyInt, _Shift, hash_function, equals>(initialcapacity, factor)),
  84                 list(NULL),
  85                 tail(NULL)
  86         {
  87         }
  88
  89         /** @brief Hashset destructor */
  90         ~Hashset() {
  91                 Linknode<_Key> *tmp = list;
  92                 while (tmp != NULL) {
  93                         Linknode<_Key> *tmpnext = tmp->next;
  94                         ourfree(tmp);
  95                         tmp = tmpnext;
  96                 }
  97                 delete table;
  98         }
  99
 100         Hashset<_Key, _KeyInt, _Shift, hash_function, equals> *copy() {
 101                 Hashset<_Key, _KeyInt, _Shift, hash_function, equals> *copy = new Hashset<_Key, _KeyInt, _Shift, hash_function, equals>(table->getCapacity(), table->getLoadFactor());
 102                 SetIterator<_Key, _KeyInt, _Shift, hash_function, equals> *it = iterator();
 103                 while (it->hasNext())
 104                         copy->add(it->next());
 105                 delete it;
 106                 return copy;
 107         }
 108
 109         void reset() {
 110                 Linknode<_Key> *tmp = list;
 111                 while (tmp != NULL) {
 112                         Linknode<_Key> *tmpnext = tmp->next;
 113                         ourfree(tmp);
 114                         tmp = tmpnext;
 115                 }
 116                 list = tail = NULL;
 117                 table->reset();
 118         }
 119
 120         /** @brief Adds a new key to the hashset.  Returns false if the key
 121          *  is already present. */
 122
 123         void addAll(Hashset<_Key, _KeyInt, _Shift, hash_function, equals> *table) {
 124                 SetIterator<_Key, _KeyInt, _Shift, hash_function, equals> *it = iterator();
 125                 while (it->hasNext())
 126                         add(it->next());
 127                 delete it;
 128         }
 129
 130         /** @brief Adds a new key to the hashset.  Returns false if the key
 131          *  is already present. */
 132
 133         bool add(_Key key) {
 134                 Linknode<_Key> *val = table->get(key);
 135                 if (val == NULL) {
 136                         Linknode<_Key> *newnode = (Linknode<_Key> *)ourmalloc(sizeof(struct Linknode<_Key>));
 137                         newnode->prev = tail;
 138                         newnode->next = NULL;
 139                         newnode->key = key;
 140                         if (tail != NULL)
 141                                 tail->next = newnode;
 142                         else
 143                                 list = newnode;
 144                         tail = newnode;
 145                         table->put(key, newnode);
 146                         return true;
 147                 } else
 148                         return false;
 149         }
 150
 151         /** @brief Return random key from set. */
 152
 153         _Key getRandomElement() {
 154                 if (getSize() == 0)
 155                         return NULL;
 156                 else if (getSize() < 6) {
 157                         uint count = random() % getSize();
 158                         Linknode<_Key> *ptr = list;
 159                         while (count > 0) {
 160                                 ptr = ptr->next;
 161                                 count--;
 162                         }
 163                         return ptr->key;
 164                 } else
 165                         return table->getRandomValue()->key;
 166         }
 167
 168         /** @brief Gets the original key corresponding to this one from the
 169          *  hashset.  Returns NULL if not present. */
 170
 171         _Key get(_Key key) {
 172                 Linknode<_Key> *val = table->get(key);
 173                 if (val != NULL)
 174                         return val->key;
 175                 else
 176                         return NULL;
 177         }
 178
 179         _Key getFirstKey() {
 180                 return list->key;
 181         }
 182
 183         bool contains(_Key key) {
 184                 return table->get(key) != NULL;
 185         }
 186
 187         bool remove(_Key key) {
 188                 Linknode<_Key> *oldlinknode;
 189                 oldlinknode = table->get(key);
 190                 if (oldlinknode == NULL) {
 191                         return false;
 192                 }
 193                 table->remove(key);
 194
 195                 //remove link node from the list
 196                 if (oldlinknode->prev == NULL)
 197                         list = oldlinknode->next;
 198                 else
 199                         oldlinknode->prev->next = oldlinknode->next;
 200                 if (oldlinknode->next != NULL)
 201                         oldlinknode->next->prev = oldlinknode->prev;
 202                 else
 203                         tail = oldlinknode->prev;
 204                 ourfree(oldlinknode);
 205                 return true;
 206         }
 207
 208         unsigned int getSize() {
 209                 return table->getSize();
 210         }
 211
 212         bool isEmpty() {
 213                 return getSize() == 0;
 214         }
 215
 216         SetIterator<_Key, _KeyInt, _Shift, hash_function, equals> *iterator() {
 217                 return new SetIterator<_Key, _KeyInt, _Shift, hash_function, equals>(list, this);
 218         }
 219
 220         /** Override: new operator */
 221         void *operator new(size_t size) {
 222                 return ourmalloc(size);
 223         }
 224
 225         /** Override: delete operator */
 226         void operator delete(void *p, size_t size) {
 227                 ourfree(p);
 228         }
 229
 230         /** Override: new[] operator */
 231         void *operator new[](size_t size) {
 232                 return ourmalloc(size);
 233         }
 234
 235         /** Override: delete[] operator */
 236         void operator delete[](void *p, size_t size) {
 237                 ourfree(p);
 238         }
 239 private:
 240         Hashtable<_Key, Linknode<_Key> *, _KeyInt, _Shift, hash_function, equals> *table;
 241         Linknode<_Key> *list;
 242         Linknode<_Key> *tail;
 243 };
 244 #endif