+++ /dev/null
-#include "mlookup.h"
-
-mhashtable_t mlookup; //Global hash table
-
-// Creates a machine lookup table with size =" size"
-unsigned int mhashCreate(unsigned int size, float loadfactor) {
- mhashlistnode_t *nodes;
- // Allocate space for the hash table
- if((nodes = calloc(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;
- //Initialize the pthread_mutex variable
- pthread_mutex_init(&mlookup.locktable, NULL);
- 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;
- pthread_mutex_lock(&mlookup.locktable);
- mhashResize(newsize);
- pthread_mutex_unlock(&mlookup.locktable);
- }
- ptr = mlookup.table;
- mlookup.numelements++;
-
- index = mhashFunction(key);
-#ifdef DEBUG
- printf("DEBUG -> index = %d, key = %d, val = %x\n", index, key, val);
-#endif
- pthread_mutex_lock(&mlookup.locktable);
- 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__);
- pthread_mutex_unlock(&mlookup.locktable);
- return 1;
- }
- node->key = key;
- node->val = val;
- node->next = ptr[index].next;
- ptr[index].next = node;
- }
- pthread_mutex_unlock(&mlookup.locktable);
- 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];
- pthread_mutex_lock(&mlookup.locktable);
- while(node != NULL) {
- if(node->key == key) {
- pthread_mutex_unlock(&mlookup.locktable);
- return node->val;
- }
- node = node->next;
- }
- pthread_mutex_unlock(&mlookup.locktable);
- 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];
-
- pthread_mutex_lock(&mlookup.locktable);
- 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);
- }
- pthread_mutex_unlock(&mlookup.locktable);
- return 0;
- }
- prev = curr;
- }
- pthread_mutex_unlock(&mlookup.locktable);
- 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;
-}
-
-unsigned int *mhashGetKeys(unsigned int *numKeys)
-{
- unsigned int *keys;
- int i, keyindex;
- mhashlistnode_t *curr;
-
- pthread_mutex_lock(&mlookup.locktable);
-
- *numKeys = mlookup.numelements;
- keys = calloc(*numKeys, sizeof(unsigned int));
-
- keyindex = 0;
- for (i = 0; i < mlookup.size; i++)
- {
- if (mlookup.table[i].key != 0)
- {
- curr = &mlookup.table[i];
- while (curr != NULL)
- {
- keys[keyindex++] = curr->key;
- curr = curr->next;
- }
- }
- }
-
- if (keyindex != *numKeys)
- printf("mhashGetKeys(): WARNING: incorrect mlookup.numelements value!\n");
-
- pthread_mutex_unlock(&mlookup.locktable);
- return keys;
-}
-
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