+++ /dev/null
-#include "mlookup.h"
-
-mhashtable_t mlookup; //Global hash table
-
-unsigned int mhashCreate(unsigned int size, float loadfactor) {
- mhashlistnode_t *nodes;
- int i;
-
- // Allocate space for the hash table
- if((nodes = calloc(HASH_SIZE, sizeof(mhashlistnode_t))) == NULL) {
- printf("Calloc error %s %d\n", __FILE__, __LINE__);
- return 1;
- }
-
- mlookup.table = nodes;
- mlookup.size = size;
- mlookup.numelements = 0; // Initial number of elements in the hash
- mlookup.loadfactor = loadfactor;
- return 0;
-}
-
-// Assign to keys to bins inside hash table
-unsigned int mhashFunction(unsigned int key) {
- return( key % (mlookup.size));
-}
-
-// Insert value and key mapping into the hash table
-unsigned int mhashInsert(unsigned int key, void *val) {
- unsigned int newsize;
- int index;
- mhashlistnode_t *ptr, *node;
-
- if (mlookup.numelements > (mlookup.loadfactor * mlookup.size)) {
- //Resize Table
- newsize = 2 * mlookup.size + 1;
- mhashResize(newsize);
- }
- ptr = mlookup.table;
- mlookup.numelements++;
-
- index = mhashFunction(key);
-#ifdef DEBUG
- printf("DEBUG -> index = %d, key = %d, val = %x\n", index, key, val);
-#endif
- if(ptr[index].next == NULL && ptr[index].key == 0) { // Insert at the first position in the hashtable
- ptr[index].key = key;
- ptr[index].val = val;
- } else { // Insert in the beginning of linked list
- if ((node = calloc(1, sizeof(mhashlistnode_t))) == NULL) {
- printf("Calloc error %s, %d\n", __FILE__, __LINE__);
- return 1;
- }
- node->key = key;
- node->val = val ;
- node->next = ptr[index].next;
- ptr[index].next = node;
- }
- return 0;
-}
-
-// Return val for a given key in the hash table
-void *mhashSearch(unsigned int key) {
- int index;
- mhashlistnode_t *ptr, *node;
-
- ptr = mlookup.table; // Address of the beginning of hash table
- index = mhashFunction(key);
- node = &ptr[index];
- while(node != NULL) {
- if(node->key == key) {
- return node->val;
- }
- node = node->next;
- }
- return NULL;
-}
-
-// Remove an entry from the hash table
-unsigned int mhashRemove(unsigned int key) {
- int index;
- mhashlistnode_t *curr, *prev;
- mhashlistnode_t *ptr, *node;
-
- ptr = mlookup.table;
- index = mhashFunction(key);
- curr = &ptr[index];
-
- for (; curr != NULL; curr = curr->next) {
- if (curr->key == key) { // Find a match in the hash table
- mlookup.numelements--; // Decrement the number of elements in the global hashtable
- if ((curr == &ptr[index]) && (curr->next == NULL)) { // Delete the first item inside the hashtable with no linked list of mhashlistnode_t
- curr->key = 0;
- curr->val = NULL;
- } else if ((curr == &ptr[index]) && (curr->next != NULL)) { //Delete the first item with a linked list of mhashlistnode_t connected
- curr->key = curr->next->key;
- curr->val = curr->next->val;
- node = curr->next;
- curr->next = curr->next->next;
- free(node);
- } else { // Regular delete from linked listed
- prev->next = curr->next;
- free(curr);
- }
- return 0;
- }
- prev = curr;
- }
- return 1;
-}
-
-// Resize table
-unsigned int mhashResize(unsigned int newsize) {
- mhashlistnode_t *node, *ptr, *curr, *next; // curr and next keep track of the current and the next mhashlistnodes in a linked list
- unsigned int oldsize;
- int isfirst; // Keeps track of the first element in the mhashlistnode_t for each bin in hashtable
- int i,index;
- mhashlistnode_t *newnode;
-
- ptr = mlookup.table;
- oldsize = mlookup.size;
-
- if((node = calloc(newsize, sizeof(mhashlistnode_t))) == NULL) {
- printf("Calloc error %s %d\n", __FILE__, __LINE__);
- return 1;
- }
-
- mlookup.table = node; //Update the global hashtable upon resize()
- mlookup.size = newsize;
- mlookup.numelements = 0;
-
- for(i = 0; i < oldsize; i++) { //Outer loop for each bin in hash table
- curr = &ptr[i];
- isfirst = 1;
- while (curr != NULL) { //Inner loop to go through linked lists
- if (curr->key == 0) { //Exit inner loop if there the first element for a given bin/index is NULL
- break; //key = val =0 for element if not present within the hash table
- }
- next = curr->next;
-
- index = mhashFunction(curr->key);
-#ifdef DEBUG
- printf("DEBUG(resize) -> index = %d, key = %d, val = %x\n", index, curr->key, curr->val);
-#endif
- // Insert into the new table
- if(mlookup.table[index].next == NULL && mlookup.table[index].key == 0) {
- mlookup.table[index].key = curr->key;
- mlookup.table[index].val = curr->val;
- mlookup.numelements++;
- }else {
- if((newnode = calloc(1, sizeof(mhashlistnode_t))) == NULL) {
- printf("Calloc error %s, %d\n", __FILE__, __LINE__);
- return 1;
- }
- newnode->key = curr->key;
- newnode->val = curr->val;
- newnode->next = mlookup.table[index].next;
- mlookup.table[index].next = newnode;
- mlookup.numelements++;
- }
-
- //free the linked list of mhashlistnode_t if not the first element in the hash table
- if (isfirst != 1) {
- free(curr);
- }
-
- isfirst = 0;
- curr = next;
-
- }
- }
-
- free(ptr); //Free the memory of the old hash table
- return 0;
-}
-
-#if 0
-// Hash Resize
-vkey resize(obj_addr_table_t * table){
- int newCapacity = 2*(table->size) + 1;
- obj_listnode_t **old;
- //if ((table->hash = (obj_listnode_t **) malloc(sizeof(obj_listnode_t *)*size)) == NULL) {
-}
-
-// Hashing for the Key
-int hashKey(unsigned int key, obj_addr_table_t *table) {
- // hash32shiftmult
- int c2=0x27d4eb2d; // a prime or an odd constant
- key = (key ^ 61) ^ (key >> 16);
- key = key + (key << 3);
- key = key ^ (key >> 4);
- key = key * c2;
- key = key ^ (key >> 15);
- printf("The bucket number is %d\n", key % (table->size));
- return (key % (table->size));
-}
-
-//Add key and its address to the new ob_listnode_t
-vkey addKey(unsigned int key, objheader_t *ptr, obj_addr_table_t *table) {
- int index;
- obj_listnode_t *node;
-
- table->numelements++;
- if(table->numelements > (table->loadfactor * table->size)){
- //TODO : check if table is nearly full and then resize
- }
-
- index = hashKey(key,table);
- if ((node = (obj_listnode_t *) malloc(sizeof(obj_listnode_t))) == NULL) {
- printf("Malloc error %s %d\n", __FILE__, __LINE__);
- exit(-1);
- }
- node->key = key;
- node->object = ptr;
- node->next = table->hash[index];
- table->hash[index] = node;
- return;
-}
-// Get the address of the object header for a given key
-objheader_t *findKey(unsigned int key, obj_addr_table_t *table) {
- int index;
- obj_listnode_t *ptr;
-
- index = hashKey(key,table);
- ptr = table->hash[index];
- while(ptr != NULL) {
- if (ptr->key == key) {
- return ptr->object;
- }
- ptr = ptr->next;
- }
- return NULL;
-}
-// Remove the pointer to the object header from a linked list of obj_listnode_t given an key
-int removeKey(unsigned int key, obj_addr_table_t *table) {
- int index;
- obj_listnode_t *curr, *prev; // prev points to previous node and curr points to the node to be deleted
-
- index = hashKey(key,table);
- prev = curr = table->hash[index];
- for (; curr != NULL; curr = curr->next) {
- if (curr->key == key) { // Find a match in the hash table
- table->numelements--;
- prev->next = curr->next;
- if (table->hash[index] == curr) { // Special case when there is one element pointed by the hash table
- table->hash[index] = NULL;
- }
- free(curr);
- return 0;
- }
- prev = curr;
- }
- return -1;
-}
-
-#endif