version2/src/C/hashtable.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 /** @file hashtable.h
  11  *  @brief Hashtable.  Standard chained bucket variety.
  12  */
  13
  14 #ifndef HASHTABLE_H__
  15 #define HASHTABLE_H__
  16
  17 #include <stdlib.h>
  18 #include <stdio.h>
  19 #include <string.h>
  20 #include "common.h"
  21 #include "mymemory.h"
  22
  23 /**
  24  * @brief Hashtable node
  25  *
  26  * @tparam _Key    Type name for the key
  27  * @tparam _Val    Type name for the values to be stored
  28  */
  29 template<typename _Key, typename _Val>
  30 struct Hashlistnode {
  31         _Key key;
  32         _Val val;
  33         uint hashcode;
  34 };
  35
  36 template<typename _Key, int _Shift, typename _KeyInt>
  37 inline unsigned int defaultHashFunction(_Key hash) {
  38         return (unsigned int)(((_KeyInt)hash) >> _Shift);
  39 }
  40
  41 template<typename _Key>
  42 inline bool defaultEquals(_Key key1, _Key key2) {
  43         return key1 == key2;
  44 }
  45
  46 /**
  47  * @brief A simple, custom hash table
  48  *
  49  * By default it is snapshotting, but you can pass in your own allocation
  50  * functions. Note that this table does not support the value 0 (NULL) used as
  51  * a key and is designed primarily with pointer-based keys in mind. Other
  52  * primitive key types are supported only for non-zero values.
  53  *
  54  * @tparam _Key    Type name for the key
  55  * @tparam _Val    Type name for the values to be stored
  56  * @tparam _KeyInt int32_t type that is at least as large as _Key. Used for key
  57  *                 manipulation and storage.
  58  * @tparam _Shift  Logical shift to apply to all keys. Default 0.
  59  */
  60 template<typename _Key, typename _Val, typename _KeyInt = uintptr_t, int _Shift = 0, unsigned int (*hash_function)(_Key) = defaultHashFunction<_Key, _Shift, _KeyInt>, bool (*equals)(_Key, _Key) = defaultEquals<_Key> >
  61 class Hashtable {
  62 public:
  63         /**
  64          * @brief Hash table constructor
  65          * @param initialcapacity Sets the initial capacity of the hash table.
  66          * Default size 1024.
  67          * @param factor Sets the percentage full before the hashtable is
  68          * resized. Default ratio 0.5.
  69          */
  70         Hashtable(unsigned int initialcapacity = 1024, double factor = 0.5) {
  71                 // Allocate space for the hash table
  72                 table = (struct Hashlistnode<_Key, _Val> *)ourcalloc(initialcapacity, sizeof(struct Hashlistnode<_Key, _Val>));
  73                 zero = NULL;
  74                 loadfactor = factor;
  75                 capacity = initialcapacity;
  76                 capacitymask = initialcapacity - 1;
  77
  78                 threshold = (unsigned int)(initialcapacity * loadfactor);
  79                 size = 0;                                                       // Initial number of elements in the hash
  80         }
  81
  82         /** @brief Hash table destructor */
  83         ~Hashtable() {
  84                 ourfree(table);
  85                 if (zero)
  86                         ourfree(zero);
  87         }
  88
  89         /** Override: new operator */
  90         void *operator new(size_t size) {
  91                 return ourmalloc(size);
  92         }
  93
  94         /** Override: delete operator */
  95         void operator delete(void *p, size_t size) {
  96                 ourfree(p);
  97         }
  98
  99         /** Override: new[] operator */
 100         void *operator new[](size_t size) {
 101                 return ourmalloc(size);
 102         }
 103
 104         /** Override: delete[] operator */
 105         void operator delete[](void *p, size_t size) {
 106                 ourfree(p);
 107         }
 108
 109         /** @brief Reset the table to its initial state. */
 110         void reset() {
 111                 memset(table, 0, capacity * sizeof(struct Hashlistnode<_Key, _Val>));
 112                 if (zero) {
 113                         ourfree(zero);
 114                         zero = NULL;
 115                 }
 116                 size = 0;
 117         }
 118
 119         /** Doesn't work with zero value */
 120         _Val getRandomValue() {
 121                 while (true) {
 122                         unsigned int index = random() & capacitymask;
 123                         struct Hashlistnode<_Key, _Val> *bin = &table[index];
 124                         if (bin->key != NULL && bin->val != NULL) {
 125                                 return bin->val;
 126                         }
 127                 }
 128         }
 129
 130         void resetAndDeleteKeys() {
 131                 for (unsigned int i = 0; i < capacity; i++) {
 132                         struct Hashlistnode<_Key, _Val> *bin = &table[i];
 133                         if (bin->key != NULL) {
 134                                 delete bin->key;
 135                                 bin->key = NULL;
 136                                 if (bin->val != NULL) {
 137                                         bin->val = NULL;
 138                                 }
 139                         }
 140                 }
 141                 if (zero) {
 142                         ourfree(zero);
 143                         zero = NULL;
 144                 }
 145                 size = 0;
 146         }
 147
 148         void resetAndDeleteVals() {
 149                 for (unsigned int i = 0; i < capacity; i++) {
 150                         struct Hashlistnode<_Key, _Val> *bin = &table[i];
 151                         if (bin->key != NULL) {
 152                                 bin->key = NULL;
 153                                 if (bin->val != NULL) {
 154                                         delete bin->val;
 155                                         bin->val = NULL;
 156                                 }
 157                         }
 158                 }
 159                 if (zero) {
 160                         if (zero->val != NULL)
 161                                 delete zero->val;
 162                         ourfree(zero);
 163                         zero = NULL;
 164                 }
 165                 size = 0;
 166         }
 167
 168         void resetAndFreeVals() {
 169                 for (unsigned int i = 0; i < capacity; i++) {
 170                         struct Hashlistnode<_Key, _Val> *bin = &table[i];
 171                         if (bin->key != NULL) {
 172                                 bin->key = NULL;
 173                                 if (bin->val != NULL) {
 174                                         ourfree(bin->val);
 175                                         bin->val = NULL;
 176                                 }
 177                         }
 178                 }
 179                 if (zero) {
 180                         if (zero->val != NULL)
 181                                 ourfree(zero->val);
 182                         ourfree(zero);
 183                         zero = NULL;
 184                 }
 185                 size = 0;
 186         }
 187
 188         /**
 189          * @brief Put a key/value pair into the table
 190          * @param key The key for the new value; must not be 0 or NULL
 191          * @param val The value to store in the table
 192          */
 193         _Val put(_Key key, _Val val) {
 194                 /* Hashtable cannot handle 0 as a key */
 195                 if (!key) {
 196                         _Val oldval;
 197                         if (!zero) {
 198                                 zero = (struct Hashlistnode<_Key, _Val> *)ourmalloc(sizeof(struct Hashlistnode<_Key, _Val>));
 199                                 size++;
 200                                 oldval = (_Val) 0;
 201                         } else
 202                                 oldval = zero->val;
 203                         zero->key = key;
 204                         zero->val = val;
 205                         return oldval;
 206                 }
 207
 208                 if (size > threshold)
 209                         resize(capacity << 1);
 210
 211                 struct Hashlistnode<_Key, _Val> *search;
 212
 213                 unsigned int hashcode = hash_function(key);
 214                 unsigned int index = hashcode;
 215                 do {
 216                         index &= capacitymask;
 217                         search = &table[index];
 218                         if (!search->key) {
 219                                 //key is null, probably done
 220                                 break;
 221                         }
 222                         if (search->hashcode == hashcode)
 223                                 if (equals(search->key, key)) {
 224                                         _Val oldval = search->val;
 225                                         search->val = val;
 226                                         return oldval;
 227                                 }
 228                         index++;
 229                 } while (true);
 230
 231                 search->key = key;
 232                 search->val = val;
 233                 search->hashcode = hashcode;
 234                 size++;
 235                 return (_Val) 0;
 236         }
 237
 238         /**
 239          * @brief Lookup the corresponding value for the given key
 240          * @param key The key for finding the value; must not be 0 or NULL
 241          * @return The value in the table, if the key is found; otherwise 0
 242          */
 243         _Val get(_Key key) const {
 244                 struct Hashlistnode<_Key, _Val> *search;
 245
 246                 /* Hashtable cannot handle 0 as a key */
 247                 if (!key) {
 248                         if (zero)
 249                                 return zero->val;
 250                         else
 251                                 return (_Val) 0;
 252                 }
 253
 254                 unsigned int hashcode = hash_function(key);
 255                 unsigned int oindex = hashcode & capacitymask;
 256                 unsigned int index = oindex;
 257                 do {
 258                         search = &table[index];
 259                         if (!search->key) {
 260                                 if (!search->val)
 261                                         break;
 262                         } else
 263                         if (hashcode == search->hashcode)
 264                                 if (equals(search->key, key))
 265                                         return search->val;
 266                         index++;
 267                         index &= capacitymask;
 268                         if (index == oindex)
 269                                 break;
 270                 } while (true);
 271                 return (_Val)0;
 272         }
 273
 274         /**
 275          * @brief Remove the given key and return the corresponding value
 276          * @param key The key for finding the value; must not be 0 or NULL
 277          * @return The value in the table, if the key is found; otherwise 0
 278          */
 279         _Val remove(_Key key) {
 280                 struct Hashlistnode<_Key, _Val> *search;
 281
 282                 /* Hashtable cannot handle 0 as a key */
 283                 if (!key) {
 284                         if (!zero) {
 285                                 return (_Val)0;
 286                         } else {
 287                                 _Val v = zero->val;
 288                                 ourfree(zero);
 289                                 zero = NULL;
 290                                 size--;
 291                                 return v;
 292                         }
 293                 }
 294
 295
 296                 unsigned int hashcode = hash_function(key);
 297                 unsigned int index = hashcode;
 298                 do {
 299                         index &= capacitymask;
 300                         search = &table[index];
 301                         if (!search->key) {
 302                                 if (!search->val)
 303                                         break;
 304                         } else
 305                         if (hashcode == search->hashcode)
 306                                 if (equals(search->key, key)) {
 307                                         _Val v = search->val;
 308                                         //empty out this bin
 309                                         search->val = (_Val) 1;
 310                                         search->key = 0;
 311                                         size--;
 312                                         return v;
 313                                 }
 314                         index++;
 315                 } while (true);
 316                 return (_Val)0;
 317         }
 318
 319         unsigned int getSize() const {
 320                 return size;
 321         }
 322
 323
 324         /**
 325          * @brief Check whether the table contains a value for the given key
 326          * @param key The key for finding the value; must not be 0 or NULL
 327          * @return True, if the key is found; false otherwise
 328          */
 329         bool contains(_Key key) const {
 330                 struct Hashlistnode<_Key, _Val> *search;
 331
 332                 /* Hashtable cannot handle 0 as a key */
 333                 if (!key) {
 334                         return zero != NULL;
 335                 }
 336
 337                 unsigned int index = hash_function(key);
 338                 unsigned int hashcode = index;
 339                 do {
 340                         index &= capacitymask;
 341                         search = &table[index];
 342                         if (!search->key) {
 343                                 if (!search->val)
 344                                         break;
 345                         } else
 346                         if (hashcode == search->hashcode)
 347                                 if (equals(search->key, key))
 348                                         return true;
 349                         index++;
 350                 } while (true);
 351                 return false;
 352         }
 353
 354         /**
 355          * @brief Resize the table
 356          * @param newsize The new size of the table
 357          */
 358         void resize(unsigned int newsize) {
 359                 struct Hashlistnode<_Key, _Val> *oldtable = table;
 360                 struct Hashlistnode<_Key, _Val> *newtable;
 361                 unsigned int oldcapacity = capacity;
 362
 363                 if ((newtable = (struct Hashlistnode<_Key, _Val> *)ourcalloc(newsize, sizeof(struct Hashlistnode<_Key, _Val>))) == NULL) {
 364                         model_print("calloc error %s %d\n", __FILE__, __LINE__);
 365                         exit(EXIT_FAILURE);
 366                 }
 367
 368                 table = newtable;                                                                                       // Update the global hashtable upon resize()
 369                 capacity = newsize;
 370                 capacitymask = newsize - 1;
 371
 372                 threshold = (unsigned int)(newsize * loadfactor);
 373
 374                 struct Hashlistnode<_Key, _Val> *bin = &oldtable[0];
 375                 struct Hashlistnode<_Key, _Val> *lastbin = &oldtable[oldcapacity];
 376                 for (; bin < lastbin; bin++) {
 377                         _Key key = bin->key;
 378
 379                         struct Hashlistnode<_Key, _Val> *search;
 380                         if (!key)
 381                                 continue;
 382
 383                         unsigned int hashcode = bin->hashcode;
 384                         unsigned int index = hashcode;
 385                         do {
 386                                 index &= capacitymask;
 387                                 search = &table[index];
 388                                 index++;
 389                         } while (search->key);
 390
 391                         search->hashcode = hashcode;
 392                         search->key = key;
 393                         search->val = bin->val;
 394                 }
 395
 396                 ourfree(oldtable);                                                                                              // Free the memory of the old hash table
 397         }
 398         double getLoadFactor() {return loadfactor;}
 399         unsigned int getCapacity() {return capacity;}
 400         struct Hashlistnode<_Key, _Val> *table;
 401         struct Hashlistnode<_Key, _Val> *zero;
 402         unsigned int capacity;
 403         unsigned int size;
 404 private:
 405         unsigned int capacitymask;
 406         unsigned int threshold;
 407         double loadfactor;
 408 };
 409
 410 #endif/* __HASHTABLE_H__ */