counter_hash.c

   1 /* hash table */
   2
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <netinet/in.h>
   6 #include "counter_hash.h"
   7 #include "hash.h"
   8 #include "iftop.h"
   9
  10 #define hash_table_size 256
  11
  12 int counter_hash_compare(void* a, void* b) {
  13     return *(long*)a == *(long*)b;
  14 }
  15
  16 int counter_hash_hash(void* key) {
  17     int hash;
  18     long addr;
  19
  20     addr = *(long*)key;
  21
  22     hash = ((addr & 0x000000FF)
  23             + (addr & 0x0000FF00 >> 8)
  24             + (addr & 0x00FF0000 >> 16)
  25             + (addr & 0xFF000000 >> 24)
  26            ) % 0xFF;
  27
  28     return hash;
  29 }
  30
  31 void* counter_hash_copy_key(void* orig) {
  32     struct in_addr* copy;
  33     copy = xmalloc(sizeof *copy);
  34     *copy = *(struct in_addr*)orig;
  35     return copy;
  36 }
  37
  38 void counter_hash_delete_key(void* key) {
  39     free(key);
  40 }
  41
  42 /*
  43  * Allocate and return a hash
  44  */
  45 hash_type* counter_hash_create() {
  46     hash_type* hash_table;
  47     hash_table = xcalloc(hash_table_size, sizeof *hash_table);
  48     hash_table->size = hash_table_size;
  49     hash_table->compare = &counter_hash_compare;
  50     hash_table->hash = &counter_hash_hash;
  51     hash_table->delete_key = &counter_hash_delete_key;
  52     hash_table->copy_key = &counter_hash_copy_key;
  53     hash_initialise(hash_table);
  54     return hash_table;
  55 }
  56