+/* Copyright (c) 2015 Regents of the University of California
+ *
+ * Author: Brian Demsky <bdemsky@uci.edu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
/** @file hashtable.h
* @brief Hashtable. Standard chained bucket variety.
*/
_Val val;
};
+template<typename _Key, int _Shift, typename _KeyInt>
+inline unsigned int default_hash_function(_Key hash) {
+ return (unsigned int)(((_KeyInt)hash) >> _Shift);
+}
+
+template<typename _Key>
+inline bool default_equals(_Key key1, _Key key2) {
+ return key1 == key2;
+}
+
/**
* @brief A simple, custom hash table
*
* @tparam _free Provide your own 'free' for the table, or default to
* snapshotting.
*/
-template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void * (* _malloc)(size_t) = snapshot_malloc, void * (* _calloc)(size_t, size_t) = snapshot_calloc, void (*_free)(void *) = snapshot_free>
+template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void * (*_malloc)(size_t) = snapshot_malloc, void * (*_calloc)(size_t, size_t) = snapshot_calloc, void (*_free)(void *) = snapshot_free, unsigned int (*hash_function)(_Key) = default_hash_function<_Key, _Shift, _KeyInt>, bool (*equals)(_Key, _Key) = default_equals<_Key> >
class HashTable {
public:
/**
HashTable(unsigned int initialcapacity = 1024, double factor = 0.5) {
// Allocate space for the hash table
table = (struct hashlistnode<_Key, _Val> *)_calloc(initialcapacity, sizeof(struct hashlistnode<_Key, _Val>));
+ zero = NULL;
loadfactor = factor;
capacity = initialcapacity;
capacitymask = initialcapacity - 1;
/** @brief Hash table destructor */
~HashTable() {
_free(table);
+ if (zero)
+ _free(zero);
}
/** Override: new operator */
/** @brief Reset the table to its initial state. */
void reset() {
memset(table, 0, capacity * sizeof(struct hashlistnode<_Key, _Val>));
+ if (zero) {
+ _free(zero);
+ zero = NULL;
+ }
+ size = 0;
+ }
+
+ void resetanddelete() {
+ for(unsigned int i=0;i<capacity;i++) {
+ struct hashlistnode<_Key, _Val> *bin = &table[i];
+ if (bin->key != NULL) {
+ bin->key = NULL;
+ if (bin->val != NULL) {
+ delete bin->val;
+ bin->val = NULL;
+ }
+ }
+ }
+ if (zero) {
+ if (zero->val != NULL)
+ delete zero->val;
+ _free(zero);
+ zero = NULL;
+ }
+ size = 0;
+ }
+
+ void resetandfree() {
+ for(unsigned int i=0;i<capacity;i++) {
+ struct hashlistnode<_Key, _Val> *bin = &table[i];
+ if (bin->key != NULL) {
+ bin->key = NULL;
+ if (bin->val != NULL) {
+ _free(bin->val);
+ bin->val = NULL;
+ }
+ }
+ }
+ if (zero) {
+ if (zero->val != NULL)
+ _free(zero->val);
+ _free(zero);
+ zero = NULL;
+ }
size = 0;
}
*/
void put(_Key key, _Val val) {
/* HashTable cannot handle 0 as a key */
- ASSERT(key);
+ if (!key) {
+ if (!zero) {
+ zero=(struct hashlistnode<_Key, _Val> *)_malloc(sizeof(struct hashlistnode<_Key, _Val>));
+ size++;
+ }
+ zero->key=key;
+ zero->val=val;
+ return;
+ }
if (size > threshold)
resize(capacity << 1);
struct hashlistnode<_Key, _Val> *search;
+ struct hashlistnode<_Key, _Val> *first = NULL;
- unsigned int index = ((_KeyInt)key) >> _Shift;
+ unsigned int index = hash_function(key) & capacitymask;
+ unsigned int oindex = index;
do {
- index &= capacitymask;
search = &table[index];
- if (search->key == key) {
+ if (!search->key) {
+ //key is null, probably done
+ if (!search->val)
+ break;
+ if (first == NULL)
+ first = search;
+ }
+ if (equals(search->key, key)) {
search->val = val;
return;
}
- index++;
- } while (search->key);
+ index = (index + 1) & capacitymask;
+ if (index == oindex) {
+ if (first == NULL)
+ exit(-1);
+ break;
+ }
+ } while (true);
- search->key = key;
- search->val = val;
+ if (first != NULL) {
+ first->key = key;
+ first->val = val;
+ } else {
+ search->key = key;
+ search->val = val;
+ }
size++;
}
struct hashlistnode<_Key, _Val> *search;
/* HashTable cannot handle 0 as a key */
- ASSERT(key);
+ if (!key) {
+ if (zero)
+ return zero->val;
+ else
+ return (_Val) 0;
+ }
- unsigned int index = ((_KeyInt)key) >> _Shift;
+ unsigned int oindex = hash_function(key) & capacitymask;
+ unsigned int index = oindex;
do {
- index &= capacitymask;
search = &table[index];
- if (search->key == key)
+ if (!search->key) {
+ if (!search->val)
+ break;
+ } else
+ if (equals(search->key, key))
return search->val;
index++;
- } while (search->key);
+ index &= capacitymask;
+ if (index==oindex)
+ break;
+ } while (true);
+ return (_Val)0;
+ }
+
+ /**
+ * @brief Remove the given key and return the corresponding value
+ * @param key The key for finding the value; must not be 0 or NULL
+ * @return The value in the table, if the key is found; otherwise 0
+ */
+ _Val remove(_Key key) {
+ struct hashlistnode<_Key, _Val> *search;
+
+ /* HashTable cannot handle 0 as a key */
+ if (!key) {
+ if (!zero) {
+ return (_Val)0;
+ } else {
+ _Val v=zero->val;
+ _free(zero);
+ zero=NULL;
+ size--;
+ return v;
+ }
+ }
+
+
+ unsigned int index = hash_function(key);
+ do {
+ index &= capacitymask;
+ search = &table[index];
+ if (!search->key) {
+ if (!search->val)
+ break;
+ } else
+ if (equals(search->key, key)) {
+ _Val v=search->val;
+ //empty out this bin
+ search->val=(_Val) 1;
+ search->key=0;
+ size--;
+ return v;
+ }
+ index++;
+ } while (true);
return (_Val)0;
}
+ unsigned int getSize() const {
+ return size;
+ }
+
+ bool isEmpty() {
+ return size == 0;
+ }
+
/**
* @brief Check whether the table contains a value for the given key
* @param key The key for finding the value; must not be 0 or NULL
struct hashlistnode<_Key, _Val> *search;
/* HashTable cannot handle 0 as a key */
- ASSERT(key);
+ if (!key) {
+ return zero!=NULL;
+ }
- unsigned int index = ((_KeyInt)key) >> _Shift;
+ unsigned int index = hash_function(key);
do {
index &= capacitymask;
search = &table[index];
- if (search->key == key)
+ if (!search->key) {
+ if (!search->val)
+ break;
+ } else
+ if (equals(search->key, key))
return true;
index++;
- } while (search->key);
+ } while (true);
return false;
}
_Key key = bin->key;
struct hashlistnode<_Key, _Val> *search;
+ if (!key)
+ continue;
- unsigned int index = ((_KeyInt)key) >> _Shift;
+ unsigned int index = hash_function(key);
do {
index &= capacitymask;
search = &table[index];
_free(oldtable); // Free the memory of the old hash table
}
-
-private:
+ double getLoadFactor() {return loadfactor;}
+ unsigned int getCapacity() {return capacity;}
struct hashlistnode<_Key, _Val> *table;
+ struct hashlistnode<_Key, _Val> *zero;
unsigned int capacity;
unsigned int size;
+private:
unsigned int capacitymask;
unsigned int threshold;
double loadfactor;