+/* 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.
*/
-#ifndef HASHTABLE_H
-#define HASHTABLE_H
+#ifndef __HASHTABLE_H__
+#define __HASHTABLE_H__
#include <stdlib.h>
#include <stdio.h>
#include "common.h"
/**
- * Hashtable linked node class, for chained storage of hash table conflicts. By
- * default it is snapshotting, but you can pass in your own allocation
- * functions.
+ * @brief HashTable node
*
* @tparam _Key Type name for the key
* @tparam _Val Type name for the values to be stored
- * @tparam _malloc Provide your own 'malloc' for the table, or default to
- * snapshotting.
- * @tparam _calloc Provide your own 'calloc' for the table, or default to
- * snapshotting.
- * @tparam _free Provide your own 'free' for the table, or default to
- * snapshotting.
*/
template<typename _Key, typename _Val>
-
struct hashlistnode {
_Key key;
_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;
+}
+
/**
- * Hashtable class. By default it is snapshotting, but you can pass in your own
- * allocation functions.
+ * @brief A simple, custom hash table
+ *
+ * By default it is snapshotting, but you can pass in your own allocation
+ * functions. Note that this table does not support the value 0 (NULL) used as
+ * a key and is designed primarily with pointer-based keys in mind. Other
+ * primitive key types are supported only for non-zero values.
*
* @tparam _Key Type name for the key
* @tparam _Val Type name for the values to be stored
* @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>
- class HashTable {
- public:
+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:
/**
- * Constructor
+ * @brief Hash table constructor
* @param initialcapacity Sets the initial capacity of the hash table.
* Default size 1024.
* @param factor Sets the percentage full before the hashtable is
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;
threshold = (unsigned int)(initialcapacity * loadfactor);
- size = 0; // Initial number of elements in the hash
+ size = 0; // Initial number of elements in the hash
}
- /** Destructor */
+ /** @brief Hash table destructor */
~HashTable() {
_free(table);
+ if (zero)
+ _free(zero);
}
/** Override: new operator */
_free(p);
}
- /** Reset the table to its initial state. */
+ /** @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;
}
- /** Put a key value pair into the table. */
+ /**
+ * @brief Put a key/value pair into the table
+ * @param key The key for the new value; must not be 0 or NULL
+ * @param val The value to store in the table
+ */
void put(_Key key, _Val val) {
+ /* HashTable cannot handle 0 as a 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 = 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++;
}
- /** Lookup the corresponding value for the given key. */
- _Val get(_Key key) {
+ /**
+ * @brief Lookup the corresponding value for the given key
+ * @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 get(_Key key) const {
struct hashlistnode<_Key, _Val> *search;
- unsigned int index = ((_KeyInt)key) >> _Shift;
+ /* HashTable cannot handle 0 as a key */
+ if (!key) {
+ if (zero)
+ return zero->val;
+ else
+ return (_Val) 0;
+ }
+
+ unsigned int oindex = hash_function(key) & capacitymask;
+ unsigned int index = oindex;
do {
- index = 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++;
+ 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;
+ struct hashlistnode<_Key, _Val> *replace;
+
+ /* 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 {
+ // The case where an item is found
+ if (equals(search->key, key)) {
+ unsigned int j = index;
+ _Val v = search->val;
+ size--;
+
+ // Idea: keep bins contiguous
+ while (true) {
+ search->val = 0;
+ search->key = 0;
+
+ while (true) {
+ j = (j + 1) & capacitymask;
+ replace = &table[j];
+
+ if (!replace->key && !replace->val) {
+ return v;
+ }
+
+ unsigned int hash = hash_function(replace->key) & capacitymask;
+ if (index <= j && index < hash && hash <= j)
+ continue;
+ else if (index > j && (index < hash || hash <= j) )
+ continue;
+ else
+ break;
+ }
+
+ table[index] = table[j];
+ index = j;
+ search = &table[index];
+ }
+ }
}
index++;
- } while (search->key);
- return (_Val) 0;
+ } while (true);
+ return (_Val)0;
+ }
+
+ unsigned int getSize() const {
+ return size;
+ }
+
+ bool isEmpty() {
+ return size == 0;
}
- /** Check whether the table contains a value for the given key. */
- bool contains(_Key key) {
+ /**
+ * @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
+ * @return True, if the key is found; false otherwise
+ */
+ bool contains(_Key key) const {
struct hashlistnode<_Key, _Val> *search;
- unsigned int index = ((_KeyInt)key) >> _Shift;
+ /* HashTable cannot handle 0 as a key */
+ if (!key) {
+ return zero!=NULL;
+ }
+
+ unsigned int index = hash_function(key);
do {
- index = index & capacitymask;
+ 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;
}
- /** Resize the table. */
+ /**
+ * @brief Resize the table
+ * @param newsize The new size of the table
+ */
void resize(unsigned int newsize) {
struct hashlistnode<_Key, _Val> *oldtable = table;
struct hashlistnode<_Key, _Val> *newtable;
unsigned int oldcapacity = capacity;
- if ((newtable = (struct hashlistnode<_Key, _Val> *) _calloc(newsize, sizeof(struct hashlistnode<_Key, _Val>))) == NULL) {
- model_print("Calloc error %s %d\n", __FILE__, __LINE__);
- exit(-1);
+ if ((newtable = (struct hashlistnode<_Key, _Val> *)_calloc(newsize, sizeof(struct hashlistnode<_Key, _Val>))) == NULL) {
+ model_print("calloc error %s %d\n", __FILE__, __LINE__);
+ exit(EXIT_FAILURE);
}
- table = newtable; //Update the global hashtable upon resize()
+ table = newtable; // Update the global hashtable upon resize()
capacity = newsize;
capacitymask = newsize - 1;
- threshold = (unsigned int) (newsize * loadfactor);
+ threshold = (unsigned int)(newsize * loadfactor);
struct hashlistnode<_Key, _Val> *bin = &oldtable[0];
struct hashlistnode<_Key, _Val> *lastbin = &oldtable[oldcapacity];
- for (; bin < lastbin; bin++) {
+ for (;bin < lastbin;bin++) {
_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 = index & capacitymask;
+ index &= capacitymask;
search = &table[index];
index++;
} while (search->key);
search->val = bin->val;
}
- _free(oldtable); //Free the memory of the old hash table
+ _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;
};
-#endif
+
+#endif /* __HASHTABLE_H__ */
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