* @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 <string.h>
#include "mymemory.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;
};
/**
- * 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 {
+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:
/**
- * 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
* resized. Default ratio 0.5.
*/
- HashTable(unsigned int initialcapacity=1024, double factor=0.5) {
+ 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>));
+ table = (struct hashlistnode<_Key, _Val> *)_calloc(initialcapacity, sizeof(struct hashlistnode<_Key, _Val>));
loadfactor = factor;
capacity = initialcapacity;
capacitymask = initialcapacity - 1;
- threshold = (unsigned int) (initialcapacity*loadfactor);
+ threshold = (unsigned int)(initialcapacity * loadfactor);
size = 0; // Initial number of elements in the hash
}
- /** Destructor */
+ /** @brief Hash table destructor */
~HashTable() {
_free(table);
}
_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>));
- size=0;
+ memset(table, 0, capacity * sizeof(struct hashlistnode<_Key, _Val>));
+ 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 */
+ ASSERT(key);
+
if (size > threshold)
resize(capacity << 1);
- struct hashlistnode<_Key,_Val> *search;
+ struct hashlistnode<_Key, _Val> *search;
- unsigned int index=((_KeyInt)key)>>_Shift;
+ unsigned int index = ((_KeyInt)key) >> _Shift;
do {
- index=index&capacitymask;
+ index &= capacitymask;
search = &table[index];
- if (search->key==key) {
- search->val=val;
+ if (search->key == key) {
+ search->val = val;
return;
}
index++;
- } while(search->key);
-
- search->key=key;
- search->val=val;
+ } while (search->key);
+
+ search->key = key;
+ search->val = val;
size++;
}
- /** Lookup the corresponding value for the given key. */
- _Val get(_Key key) {
- struct hashlistnode<_Key,_Val> *search;
+ /**
+ * @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;
+
+ /* HashTable cannot handle 0 as a key */
+ ASSERT(key);
- unsigned int index=((_KeyInt)key)>>_Shift;
+ unsigned int index = ((_KeyInt)key) >> _Shift;
do {
- index=index&capacitymask;
+ index &= capacitymask;
search = &table[index];
- if (search->key==key) {
+ if (search->key == key)
return search->val;
- }
index++;
- } while(search->key);
- return (_Val) 0;
+ } while (search->key);
+ return (_Val)0;
}
- /** Check whether the table contains a value for the given key. */
- bool contains(_Key key) {
- struct hashlistnode<_Key,_Val> *search;
+ /**
+ * @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;
+
+ /* HashTable cannot handle 0 as a key */
+ ASSERT(key);
- unsigned int index=((_KeyInt)key)>>_Shift;
+ unsigned int index = ((_KeyInt)key) >> _Shift;
do {
- index=index&capacitymask;
+ index &= capacitymask;
search = &table[index];
- if (search->key==key) {
+ if (search->key == key)
return true;
- }
index++;
- } while(search->key);
+ } while (search->key);
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;
+ 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) {
- printf("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++) {
+ _Key key = bin->key;
- struct hashlistnode<_Key, _Val> * bin = &oldtable[0];
- struct hashlistnode<_Key, _Val> * lastbin = &oldtable[oldcapacity];
- for(; bin < lastbin; bin++) {
- _Key key=bin->key;
+ struct hashlistnode<_Key, _Val> *search;
- struct hashlistnode<_Key,_Val> *search;
-
- unsigned int index=((_KeyInt)key)>>_Shift;
+ unsigned int index = ((_KeyInt)key) >> _Shift;
do {
- index=index&capacitymask;
+ index &= capacitymask;
search = &table[index];
index++;
- } while(search->key);
+ } while (search->key);
- search->key=key;
- search->val=bin->val;
+ search->key = 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:
- struct hashlistnode<_Key,_Val> *table;
+ struct hashlistnode<_Key, _Val> *table;
unsigned int capacity;
unsigned int size;
unsigned int capacitymask;
unsigned int threshold;
double loadfactor;
};
-#endif
+
+#endif /* __HASHTABLE_H__ */
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