--- /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
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