#include "dstm.h"
obj_store_t *obj_begin; // points to the first location of the object store linked list
-obj_listnode_t **hash; // points to beginning of hash table
-unsigned int hash_size; // number of entries in hash table
+//unsigned int hash_size; // number of entries in hash table
extern int classsize[];
// Initializes the pointers...currently invoked inside main()
void dstm_init(void) {
obj_begin = NULL;
- hash = NULL;
- hash_size = 0;
return;
}
// Create a new object store of a given "size" as a linked list
exit(-1);
}
tmp->size = size;
+ printf("The object store size is : %d\n", tmp->size);
tmp->top = tmp->base;
tmp->id = id++;
- tmp->next = obj_begin;
+ printf("The object store id is : %d\n", tmp->id);
+ tmp->next = obj_begin; //adds new object store to the linked list and updates obj_begin pointer to new object store node
obj_begin = tmp;
return;
}
}
// Insert the object header and object into the object store
int insertObject(obj_header_t h) {
+ extern obj_addr_table_t mlut; //declared in the main mlut=>machine look up table
unsigned int left, req; // Keeps track of the space available in the current object store
obj_header_t *header;
-
+
left = obj_begin->size - (obj_begin->top - obj_begin->base);
req = getObjSize(h) + sizeof(obj_header_t);
if (req < left) {
memcpy(obj_begin->top, &h, sizeof(obj_header_t));
header = (obj_header_t *) obj_begin->top;
- obj_begin->top = obj_begin->top + sizeof(obj_header_t) + getObjSize(h);
+ printf("The header points to : %d\n", header);
+ obj_begin->top = obj_begin->top + sizeof(obj_header_t) + getObjSize(h); //increment object store top when new object is inserted
+ printf("Top now points to :%d\n", obj_begin->top);
} else {
return -1;
}
- //TODO Update obj_addr_table
- addKey(h.oid, header);
-
+ printf("header: %d\n", header);
+ printf("The oid is : %d\n", h.oid);
+ addKey(h.oid, header, &mlut); //Update obj_addr_table
+ printf("Object id = %d\n",h.oid);
return 0;
}
// Get the size of the object for a given type
/* END object header */
/* BEGIN hash*/
-
-//hash table is an array of pointers that point to the beginning of a obj_listnode_t DS
+//obj_addr_table is a generic hash table structure
+//hash is an array of pointers that point to the beginning of a obj_listnode_t DS
// "size" in hash table is the no of indices in the hash table and each index points to a pointer for an object_header
-void createHash(int size) {
+void createHash(obj_addr_table_t *table, int size, float loadfactor) {
int i;
- if ((hash = (obj_listnode_t **) malloc(sizeof(obj_listnode_t *)*size)) == NULL) {
+ if ((table->hash = (obj_listnode_t **) malloc(sizeof(obj_listnode_t *)*size)) == NULL) {
printf("Malloc error %s %d\n", __FILE__, __LINE__);
exit(-1);
}
for (i = 0; i < size; i++) { // initialize the hash elements
- hash[i] = NULL;
+ table->hash[i] = NULL;
}
- hash_size = size;
+
+ table->size = size;
+ table->numelements = 0;
+ table->loadfactor = loadfactor;
+
return;
}
+// Hash Resize
+void 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 oid) {
- //TODO: Design a better hash function
-// return (hash_size % oid);
- return (oid % hash_size);
+int hashKey(unsigned int oid, obj_addr_table_t *table) {
+ // hash32shiftmult
+ int c2=0x27d4eb2d; // a prime or an odd constant
+ oid = (oid ^ 61) ^ (oid >> 16);
+ oid = oid + (oid << 3);
+ oid = oid ^ (oid >> 4);
+ oid = oid * c2;
+ oid = oid ^ (oid >> 15);
+ printf("The bucket number is %d\n", oid % (table->size));
+ return (oid % (table->size));
}
//Add oid and its address to the new ob_listnode_t
-void addKey(unsigned int oid, obj_header_t *ptr) {
+void addKey(unsigned int oid, obj_header_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(oid);
+ index = hashKey(oid,table);
if ((node = (obj_listnode_t *) malloc(sizeof(obj_listnode_t))) == NULL) {
printf("Malloc error %s %d\n", __FILE__, __LINE__);
exit(-1);
}
node->oid = oid;
node->object = ptr;
- node->next = hash[index];
- hash[index] = node;
+ node->next = table->hash[index];
+ table->hash[index] = node;
return;
}
// Get the address of the object header for a given oid
-obj_header_t *findKey(unsigned int oid) {
+obj_header_t *findKey(unsigned int oid, obj_addr_table_t *table) {
int index;
obj_listnode_t *ptr;
- index = hashkey(oid);
- ptr = hash[index];
+ index = hashKey(oid,table);
+ ptr = table->hash[index];
while(ptr != NULL) {
if (ptr->oid == oid) {
return ptr->object;
return NULL;
}
// Remove the pointer to the object header from a linked list of obj_listnode_t given an oid
-int removeKey(unsigned int oid) {
+int removeKey(unsigned int oid, 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(oid);
- prev = curr = hash[index];
+ index = hashKey(oid,table);
+ prev = curr = table->hash[index];
for (; curr != NULL; curr = curr->next) {
if (curr->oid == oid) { // Find a match in the hash table
+ table->numelements--;
prev->next = curr->next;
- if (hash[index] == curr) { // Special case when there is one element pointed by the hash table
- hash[index] = NULL;
+ 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;
#include <stdio.h>
#include <string.h>
+#define LOADFACTOR 0.75
+#define HASH_SIZE 100
+
enum status {CLEAN, DIRTY};
typedef struct obj_header {
struct obj_lnode *next;
} obj_listnode_t;
+/*
typedef struct obj_addr_table {
unsigned int size; //number of elements, not bytes
obj_listnode_t *table; //this should point to an array of object lists, of the specified size
} obj_addr_table_t;
+*/
+
+typedef struct hash_table {
+ obj_listnode_t **hash; // points to beginning of hash table
+ float loadfactor;
+ unsigned int numelements;
+ unsigned int size;
+}obj_addr_table_t;
typedef struct trans_record {
obj_listnode_t *obj_list;
/* end object header */
/* Prototypes for hash*/
-void createHash(int);
-int hashkey(unsigned int);
-void addKey(unsigned int, obj_header_t *);
-obj_header_t *findKey(unsigned int);
-int removeKey(unsigned int);
+void createHash(obj_addr_table_t *, int , float);
+void resize(obj_addr_table_t * table);
+int hashkey(unsigned int, obj_addr_table_t *);
+void addKey(unsigned int, obj_header_t *, obj_addr_table_t *);
+obj_header_t *findKey(unsigned int,obj_addr_table_t *);
+int removeKey(unsigned int, obj_addr_table_t *);
/* end for hash */
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