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

   1  #include "clookup.h"
   2
   3 chashtable_t *chashCreate(unsigned int size, float loadfactor) {
   4         chashtable_t *ctable;
   5         chashlistnode_t *nodes;
   6         int i;
   7
   8         if((ctable = calloc(1, sizeof(chashtable_t))) == NULL) {
   9                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
  10                 return NULL;
  11         }
  12
  13         // Allocate space for the hash table
  14         if((nodes = calloc(size, sizeof(chashlistnode_t))) == NULL) {
  15                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
  16                 return NULL;
  17         }
  18
  19         ctable->table = nodes;
  20         ctable->size = size;
  21         ctable->numelements = 0; // Initial number of elements in the hash
  22         ctable->loadfactor = loadfactor;
  23
  24         return ctable;
  25 }
  26
  27 //Finds the right bin in the hash table
  28 unsigned int chashFunction(chashtable_t *table, unsigned int key) {
  29         return ( key % (table->size));
  30 }
  31
  32 //Store objects and their pointers into hash
  33 unsigned int chashInsert(chashtable_t *table, unsigned int key, void *val) {
  34         unsigned int newsize;
  35         int index;
  36         chashlistnode_t *ptr, *node;
  37
  38         if(table->numelements > (table->loadfactor * table->size)) {
  39                 //Resize
  40                 newsize = 2 * table->size + 1;
  41                 chashResize(table,newsize);
  42         }
  43
  44         ptr = table->table;
  45         table->numelements++;
  46         index = chashFunction(table, key);
  47 #ifdef DEBUG
  48         printf("DEBUG -> index = %d, key = %d, val = %x\n", index, key, val);
  49 #endif
  50         if(ptr[index].next == NULL && ptr[index].key == 0) {    // Insert at the first position in the hashtable
  51                 ptr[index].key = key;
  52                 ptr[index].val = val;
  53         } else {                        // Insert in the beginning of linked list
  54                 if ((node = calloc(1, sizeof(chashlistnode_t))) == NULL) {
  55                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
  56                         return 1;
  57                 }
  58                 node->key = key;
  59                 node->val = val ;
  60                 node->next = ptr[index].next;
  61                 ptr[index].next = node;
  62         }
  63         return 0;
  64 }
  65
  66 // Search for an address for a given oid
  67 void *chashSearch(chashtable_t *table, unsigned int key) {
  68         int index;
  69         chashlistnode_t *ptr, *node;
  70
  71         ptr = table->table;
  72         index = chashFunction(table, key);
  73         node = &ptr[index];
  74         while(node != NULL) {
  75                 if(node->key == key) {
  76                         return node->val;
  77                 }
  78                 node = node->next;
  79         }
  80         return NULL;
  81 }
  82
  83 unsigned int chashRemove(chashtable_t *table, unsigned int key) {
  84         int index;
  85         chashlistnode_t *curr, *prev;
  86         chashlistnode_t *ptr, *node;
  87
  88         ptr = table->table;
  89         index = chashFunction(table,key);
  90         curr = &ptr[index];
  91
  92         for (; curr != NULL; curr = curr->next) {
  93                 if (curr->key == key) {         // Find a match in the hash table
  94                         table->numelements--;  // Decrement the number of elements in the global hashtable
  95                         if ((curr == &ptr[index]) && (curr->next == NULL))  { // Delete the first item inside the hashtable with no linked list of chashlistnode_t
  96                                 curr->key = 0;
  97                                 curr->val = NULL;
  98                         } else if ((curr == &ptr[index]) && (curr->next != NULL)) { //Delete the first item with a linked list of chashlistnode_t  connected
  99                                 curr->key = curr->next->key;
 100                                 curr->val = curr->next->val;
 101                                 node = curr->next;
 102                                 curr->next = curr->next->next;
 103                                 free(node);
 104                         } else {                                                // Regular delete from linked listed
 105                                 prev->next = curr->next;
 106                                 free(curr);
 107                         }
 108                         return 0;
 109                 }
 110                 prev = curr;
 111         }
 112         return 1;
 113 }
 114
 115 unsigned int chashResize(chashtable_t *table, unsigned int newsize) {
 116         chashlistnode_t *node, *ptr, *curr, *next;      // curr and next keep track of the current and the next chashlistnodes in a linked list
 117         unsigned int oldsize;
 118         int isfirst;    // Keeps track of the first element in the chashlistnode_t for each bin in hashtable
 119         int i,index;
 120         chashlistnode_t *newnode;
 121
 122         ptr = table->table;
 123         oldsize = table->size;
 124
 125         if((node = calloc(newsize, sizeof(chashlistnode_t))) == NULL) {
 126                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
 127                 return 1;
 128         }
 129
 130         table->table = node;            //Update the global hashtable upon resize()
 131         table->size = newsize;
 132         table->numelements = 0;
 133
 134         for(i = 0; i < oldsize; i++) {                  //Outer loop for each bin in hash table
 135                 curr = &ptr[i];
 136                 isfirst = 1;
 137                 while (curr != NULL) {                  //Inner loop to go through linked lists
 138                         if (curr->key == 0) {           //Exit inner loop if there the first element for a given bin/index is NULL
 139                                 break;                  //key = val =0 for element if not present within the hash table
 140                         }
 141                         next = curr->next;
 142
 143                         index = chashFunction(table, curr->key);
 144 #ifdef DEBUG
 145                         printf("DEBUG(resize) -> index = %d, key = %d, val = %x\n", index, curr->key, curr->val);
 146 #endif
 147                         // Insert into the new table
 148                         if(table->table[index].next == NULL && table->table[index].key == 0) {
 149                                 table->table[index].key = curr->key;
 150                                 table->table[index].val = curr->val;
 151                                 table->numelements++;
 152                         }else {
 153                                 if((newnode = calloc(1, sizeof(chashlistnode_t))) == NULL) {
 154                                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 155                                         return 1;
 156                                 }
 157                                 newnode->key = curr->key;
 158                                 newnode->val = curr->val;
 159                                 newnode->next = table->table[index].next;
 160                                 table->table[index].next = newnode;
 161                                 table->numelements++;
 162                         }
 163
 164                         //free the linked list of chashlistnode_t if not the first element in the hash table
 165                         if (isfirst != 1) {
 166                                 free(curr);
 167                         }
 168
 169                         isfirst = 0;
 170                         curr = next;
 171                 }
 172         }
 173
 174         free(ptr);              //Free the memory of the old hash table
 175         return 0;
 176 }
 177
 178 //Delete the entire hash table
 179 void chashDelete(chashtable_t *table) {
 180         int i, isFirst;
 181         chashlistnode_t *ptr, *curr, *next;
 182         ptr = table->table;
 183
 184         for(i=0 ; i<table->size ; i++) {
 185                 curr = &ptr[i];
 186                 isFirst = 1 ;
 187                 while(curr  != NULL) {
 188                         next = curr->next;
 189                         if(isFirst != 1) {
 190                                 free(curr);
 191                         }
 192                         isFirst = 0;
 193                         curr = next;
 194                 }
 195         }
 196
 197         free(ptr);
 198         free(table);
 199         table = NULL;
 200 }