/************************************************************************************************
IMP NOTE:
-
- All llookup hash function prototypes returns 0 or NULL when there is an error or else returns 1
+ All llookup hash function prototypes returns 0 on sucess and 1 otherwise
llookup hash is an array of lhashlistnode_t
oid = mid = 0 in a given lhashlistnode_t for each bin in the hash table ONLY if the entry is empty =>
the OID's can be any unsigned int except 0
***************************************************************************************************/
#include "llookup.h"
-extern lhashtable_t llookup; //Global Hash table
+lhashtable_t llookup; //Global Hash table
// Creates a hash table with default size HASH_SIZE and an array of lhashlistnode_t
unsigned int lhashCreate(unsigned int size, float loadfactor) {
// Allocate space for the hash table
if((nodes = calloc(HASH_SIZE, sizeof(lhashlistnode_t))) == NULL) {
printf("Calloc error %s %d\n", __FILE__, __LINE__);
- return 0;
+ return 1;
}
- for (i = 0; i < HASH_SIZE; i++)
- nodes[i].next = NULL;
llookup.table = nodes;
llookup.size = size;
llookup.numelements = 0; // Initial number of elements in the hash
llookup.loadfactor = loadfactor;
- return 1;
+ return 0;
}
// Assign to oids to bins inside hash table
unsigned int lhashInsert(unsigned int oid, unsigned int mid) {
unsigned int newsize;
int index;
- lhashlistnode_t *ptr;
- lhashlistnode_t *node;
+ lhashlistnode_t *ptr, *node;
if (llookup.numelements > (llookup.loadfactor * llookup.size)) {
//Resize Table
} else { // Insert in the linked list
if ((node = calloc(1, sizeof(lhashlistnode_t))) == NULL) {
printf("Calloc error %s, %d\n", __FILE__, __LINE__);
- return 0;
+ return 1;
}
node->oid = oid;
node->mid = mid;
node->next = ptr[index].next;
ptr[index].next = node;
}
- return 1;
+ return 0;
}
-// Search for a value in the hash table
+// Return mid for a given oid in the hash table
unsigned int lhashSearch(unsigned int oid) {
int index;
- lhashlistnode_t *ptr;
- lhashlistnode_t *tmp;
+ lhashlistnode_t *ptr, *node;
ptr = llookup.table; // Address of the beginning of hash table
index = lhashFunction(oid);
- tmp = &ptr[index];
- while(tmp != NULL) {
- if(tmp->oid == oid) {
- return tmp->mid;
+ node = &ptr[index];
+ while(node != NULL) {
+ if(node->oid == oid) {
+ return node->mid;
}
- tmp = tmp->next;
+ node = node->next;
}
return 0;
}
// Remove an entry from the hash table
unsigned int lhashRemove(unsigned int oid) {
int index;
- lhashlistnode_t *curr, *prev, *tmp;
- lhashlistnode_t *ptr;
+ lhashlistnode_t *curr, *prev;
+ lhashlistnode_t *ptr, *node;
ptr = llookup.table;
index = lhashFunction(oid);
- prev = curr = &ptr[index];
+ curr = &ptr[index];
for (; curr != NULL; curr = curr->next) {
if (curr->oid == oid) { // Find a match in the hash table
} else if ((curr == &ptr[index]) && (curr->next != NULL)) { //Delete the first item with a linked list of lhashlistnode_t connected
curr->oid = curr->next->oid;
curr->mid = curr->next->mid;
- tmp = curr->next;
+ node = curr->next;
curr->next = curr->next->next;
- free(tmp);
+ free(node);
} else { // Regular delete from linked listed
prev->next = curr->next;
free(curr);
}
- return 1;
+ return 0;
}
prev = curr;
}
- return 0;
+ return 1;
}
// Resize table
unsigned int lhashResize(unsigned int newsize) {
- lhashlistnode_t *node, *curr, *next; // curr and next keep track of the current and the next lhashlistnodes in a linked list
- lhashtable_t oldtable;
- int i, isfirst; // Keeps track of the first element in the lhashlistnode_t for each bin in hashtable
-
- oldtable.table = llookup.table; // copy orginial lhashtable_t type to a new structure
- oldtable.size = llookup.size;
- oldtable.numelements = llookup.numelements;
- oldtable.loadfactor = llookup.loadfactor;
+ lhashlistnode_t *node, *ptr, *curr, *next; // curr and next keep track of the current and the next lhashlistnodes in a linked list
+ unsigned int oldsize;
+ int isfirst; // Keeps track of the first element in the lhashlistnode_t for each bin in hashtable
+ int i,index;
+ lhashlistnode_t *newnode;
+
+ ptr = llookup.table;
+ oldsize = llookup.size;
+
if((node = calloc(newsize, sizeof(lhashlistnode_t))) == NULL) {
printf("Calloc error %s %d\n", __FILE__, __LINE__);
- return 0;
+ return 1;
}
+
llookup.table = node; //Update the global hashtable upon resize()
llookup.size = newsize;
llookup.numelements = 0;
- for(i = 0; i < oldtable.size; i++) {
- curr = next = &oldtable.table[i];
- isfirst = 1; //isfirst = true by default
- while (curr != NULL) {
+ 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->oid == 0) { //Exit inner loop if there the first element for a given bin/index is NULL
break; //oid = mid =0 for element if not present within the hash table
}
next = curr->next;
- lhashInsert(curr->oid, curr->mid); //Call hashInsert into the new resized table
+
+ index = lhashFunction(curr->oid);
+ // Insert into the new table
+ if(ptr[index].next == NULL && ptr[index].oid == 0) {
+ ptr[index].oid = curr->oid;
+ ptr[index].mid = curr->mid;
+ llookup.numelements++;
+ }else {
+ if((newnode = calloc(1, sizeof(lhashlistnode_t))) == NULL) {
+ printf("Calloc error %s, %d\n", __FILE__, __LINE__);
+ return 1;
+ }
+ newnode->oid = curr->oid;
+ newnode->mid = curr->mid;
+ newnode->next = ptr[index].next;
+ ptr[index].next = newnode;
+ llookup.numelements++;
+ }
+
+ //free the linked list of lhashlistnode_t if not the first element in the hash table
if (isfirst != 1) {
- free(curr); //free the linked list of lhashlistnode_t if not the first element in the hash table
+ free(curr);
}
- isfirst = 0; //set isFirst = false inside inner loop
+
+ isfirst = 0;
curr = next;
+
}
}
- free(oldtable.table); //free the copied hashtable calloc-ed
- return 1;
+
+ free(ptr); //Free the memory of the old hash table
+ return 0;
}
#include <stdio.h>
#include "llookup.h"
-
-lhashtable_t llookup;
+extern lhashtable_t llookup;
main()
{
int i, mid;
- if (lhashCreate(10, 0.80) == 0) {
+ if (lhashCreate(10, 0.80) == 1) {
printf("lhashCreate error\n"); //creates hashtable
}
- for (i = 1; i <= 10; i++) { // Checks the insert() and resize()
- if (lhashInsert(10*i, i) == 0)
+ for (i = 1; i <= 7; i++) { // Checks the insert() and resize()
+ if (lhashInsert(10*i, i) == 1)
printf("lhashInsert error\n");
}
- i = lhashRemove(10);//Delete first element in the hashtable
- if(i == 0)
+ i = lhashRemove(60);//Delete first element in the hashtable
+ if(i == 1)
printf("lhashRemove error ");
- for (i = 1; i <=10; i++) { // Check if it can search for all oids in hash table
+ for (i = 1; i <=7; i++) { // Check if it can search for all oids in hash table
mid = lhashSearch(10*i);
if (mid != i)
printf("lhashSearch error - mid = %d\n", mid);
printf("lhashSearch oid = %d mid = %d\n",10*i, mid);
}
- i = lhashRemove(60);
- if(i == 0)
+ i = lhashRemove(30);
+ if(i == 1)
printf("lhashRemove error ");
- for (i = 1; i <= 10; i++) { //Prints all left over elements inside hash after deletion and prints error if element not found in hash
+ for (i = 1; i <= 7; i++) { //Prints all left over elements inside hash after deletion and prints error if element not found in hash
mid = lhashSearch(10*i);
if (mid != i)
printf("lhashSearch error - mid = %d\n", mid);
printf("lhashSearch oid = %d mid = %d\n",10*i, mid);
}
+ printf(" The total number of elements in table : %d\n", llookup.numelements);
+
}
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