Robust/src/Runtime/DSTM/interface/llookup.c

   1 /************************************************************************************************
   2   IMP NOTE:
   3    All llookup hash function prototypes returns 0 on sucess and 1 otherwise
   4    llookup hash is an array of lhashlistnode_t
   5    oid = mid = 0 in a given lhashlistnode_t for each bin in the hash table ONLY if the entry is empty =>
   6    the OID's can be any unsigned int except 0
   7
   8    Uses pthreads. compile using -lpthread option
   9 ***************************************************************************************************/
  10 #include "llookup.h"
  11
  12 #ifdef SIMPLE_LLOOKUP
  13
  14 extern unsigned int *hostIpAddrs;
  15 extern unsigned int oidsPerBlock;
  16
  17 unsigned int lhashCreate(unsigned int size, float loadfactor)
  18 {
  19         return 0;
  20 }
  21
  22 unsigned int lhashInsert(unsigned int oid, unsigned int mid)
  23 {
  24         return 0;
  25 }
  26
  27 unsigned int lhashSearch(unsigned int oid)
  28 {
  29         if (oidsPerBlock == 0)
  30                 return hostIpAddrs[0];
  31         else
  32                 return hostIpAddrs[oid / oidsPerBlock];
  33 }
  34
  35 unsigned int lhashRemove(unsigned int oid)
  36 {
  37         return 0;
  38 }
  39
  40 #else
  41
  42 lhashtable_t llookup;           //Global Hash table
  43
  44 // Creates a hash table with size and an array of lhashlistnode_t
  45 unsigned int lhashCreate(unsigned int size, float loadfactor) {
  46         lhashlistnode_t *nodes;
  47         int i;
  48
  49         // Allocate space for the hash table
  50         if((nodes = calloc(size, sizeof(lhashlistnode_t))) == NULL) {
  51                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
  52                 return 1;
  53         }
  54
  55         llookup.table = nodes;
  56         llookup.size = size;
  57         llookup.numelements = 0; // Initial number of elements in the hash
  58         llookup.loadfactor = loadfactor;
  59         //Initialize the pthread_mutex variable
  60         pthread_mutex_init(&llookup.locktable, NULL);
  61         return 0;
  62 }
  63
  64 // Assign to oids to bins inside hash table
  65 unsigned int lhashFunction(unsigned int oid) {
  66         return( oid % (llookup.size));
  67 }
  68
  69 // Insert oid and mid mapping into the hash table
  70 unsigned int lhashInsert(unsigned int oid, unsigned int mid) {
  71         unsigned int newsize;
  72         int index;
  73         lhashlistnode_t *ptr, *node;
  74
  75         if (llookup.numelements > (llookup.loadfactor * llookup.size)) {
  76                 //Resize Table
  77                 newsize = 2 * llookup.size + 1;
  78                 pthread_mutex_lock(&llookup.locktable);
  79                 lhashResize(newsize);
  80                 pthread_mutex_unlock(&llookup.locktable);
  81         }
  82
  83         ptr = llookup.table;
  84         llookup.numelements++;
  85
  86         index = lhashFunction(oid);
  87 #ifdef DEBUG
  88         printf("DEBUG(insert) oid = %d, mid =%d, index =%d\n",oid,mid, index);
  89 #endif
  90         pthread_mutex_lock(&llookup.locktable);
  91         if(ptr[index].next == NULL && ptr[index].oid == 0) {    // Insert at the first position in the hashtable
  92                 ptr[index].oid = oid;
  93                 ptr[index].mid = mid;
  94         } else {                        // Insert in the linked list
  95                 if ((node = calloc(1, sizeof(lhashlistnode_t))) == NULL) {
  96                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
  97                         pthread_mutex_unlock(&llookup.locktable);
  98                         return 1;
  99                 }
 100                 node->oid = oid;
 101                 node->mid = mid;
 102                 node->next = ptr[index].next;
 103                 ptr[index].next = node;
 104         }
 105
 106         pthread_mutex_unlock(&llookup.locktable);
 107         return 0;
 108 }
 109
 110 // Return mid for a given oid in the hash table
 111 unsigned int lhashSearch(unsigned int oid) {
 112         int index;
 113         lhashlistnode_t *ptr, *node;
 114
 115         ptr = llookup.table;    // Address of the beginning of hash table
 116         index = lhashFunction(oid);
 117         node = &ptr[index];
 118         pthread_mutex_lock(&llookup.locktable);
 119         while(node != NULL) {
 120                 if(node->oid == oid) {
 121                         pthread_mutex_unlock(&llookup.locktable);
 122                         return node->mid;
 123                 }
 124                 node = node->next;
 125         }
 126         pthread_mutex_unlock(&llookup.locktable);
 127         return 0;
 128 }
 129
 130 // Remove an entry from the hash table
 131 unsigned int lhashRemove(unsigned int oid) {
 132         int index;
 133         lhashlistnode_t *curr, *prev;
 134         lhashlistnode_t *ptr, *node;
 135
 136         ptr = llookup.table;
 137         index = lhashFunction(oid);
 138         curr = &ptr[index];
 139
 140         pthread_mutex_lock(&llookup.locktable);
 141         for (; curr != NULL; curr = curr->next) {
 142                 if (curr->oid == oid) {         // Find a match in the hash table
 143                         llookup.numelements--;  // Decrement the number of elements in the global hashtable
 144                         if ((curr == &ptr[index]) && (curr->next == NULL))  { // Delete the first item inside the hashtable with no linked list of lhashlistnode_t
 145                                 curr->oid = 0;
 146                                 curr->mid = 0;
 147                         } else if ((curr == &ptr[index]) && (curr->next != NULL)) { //Delete the first item with a linked list of lhashlistnode_t  connected
 148                                 curr->oid = curr->next->oid;
 149                                 curr->mid = curr->next->mid;
 150                                 node = curr->next;
 151                                 curr->next = curr->next->next;
 152                                 free(node);
 153                         } else {                                                // Regular delete from linked listed
 154                                 prev->next = curr->next;
 155                                 free(curr);
 156                         }
 157                         pthread_mutex_unlock(&llookup.locktable);
 158                         return 0;
 159                 }
 160                 prev = curr;
 161         }
 162         pthread_mutex_unlock(&llookup.locktable);
 163         return 1;
 164 }
 165
 166 // Resize table
 167 unsigned int lhashResize(unsigned int newsize) {
 168         lhashlistnode_t *node, *ptr, *curr, *next;      // curr and next keep track of the current and the next lhashlistnodes in a linked list
 169         unsigned int oldsize;
 170         int isfirst;    // Keeps track of the first element in the lhashlistnode_t for each bin in hashtable
 171         int i,index;
 172         lhashlistnode_t *newnode;
 173
 174         ptr = llookup.table;
 175         oldsize = llookup.size;
 176
 177         if((node = calloc(newsize, sizeof(lhashlistnode_t))) == NULL) {
 178                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
 179                 return 1;
 180         }
 181
 182         llookup.table = node;           //Update the global hashtable upon resize()
 183         llookup.size = newsize;
 184         llookup.numelements = 0;
 185
 186         for(i = 0; i < oldsize; i++) {                  //Outer loop for each bin in hash table
 187                 curr = &ptr[i];
 188                 isfirst = 1;
 189                 while (curr != NULL) {                  //Inner loop to go through linked lists
 190                         if (curr->oid == 0) {           //Exit inner loop if there the first element for a given bin/index is NULL
 191                                 break;                  //oid = mid =0 for element if not present within the hash table
 192                         }
 193                         next = curr->next;
 194                         index = lhashFunction(curr->oid);
 195                         // Insert into the new table
 196                         if(llookup.table[index].next == NULL && llookup.table[index].oid == 0) {
 197                                 llookup.table[index].oid = curr->oid;
 198                                 llookup.table[index].mid = curr->mid;
 199                                 llookup.numelements++;
 200                         }else {
 201                                 if((newnode = calloc(1, sizeof(lhashlistnode_t))) == NULL) {
 202                                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 203                                         return 1;
 204                                 }
 205                                 newnode->oid = curr->oid;
 206                                 newnode->mid = curr->mid;
 207                                 newnode->next = llookup.table[index].next;
 208                                 llookup.table[index].next = newnode;
 209                                 llookup.numelements++;
 210                         }
 211
 212                         //free the linked list of lhashlistnode_t if not the first element in the hash table
 213                         if (isfirst != 1) {
 214                                 free(curr);
 215                         }
 216
 217                         isfirst = 0;
 218                         curr = next;
 219
 220                 }
 221         }
 222
 223         free(ptr);              //Free the memory of the old hash table
 224         return 0;
 225 }
 226
 227 #endif
 228