counter_hash.c


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/* hash table */

#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include "counter_hash.h"
#include "hash.h"
#include "iftop.h"

#define hash_table_size 256

int counter_hash_compare(void* a, void* b) {
    return *(long*)a == *(long*)b;
}

int counter_hash_hash(void* key) {
    int hash;
    long addr;
        
    addr = *(long*)key;

    hash = ((addr & 0x000000FF)
            + (addr & 0x0000FF00 >> 8)
            + (addr & 0x00FF0000 >> 16)
            + (addr & 0xFF000000 >> 24)
           ) % 0xFF;

    return hash;
}

void* counter_hash_copy_key(void* orig) {
    struct in_addr* copy;
    copy = xmalloc(sizeof *copy);
    *copy = *(struct in_addr*)orig;
    return copy;
}

void counter_hash_delete_key(void* key) {
    free(key);
}

/*
 * Allocate and return a hash
 */
hash_type* counter_hash_create() {
    hash_type* hash_table;
    hash_table = xcalloc(hash_table_size, sizeof *hash_table);
    hash_table->size = hash_table_size;
    hash_table->compare = &counter_hash_compare;
    hash_table->hash = &counter_hash_hash;
    hash_table->delete_key = &counter_hash_delete_key;
    hash_table->copy_key = &counter_hash_copy_key;
    hash_initialise(hash_table);
    return hash_table;
}