hashmap.c

#include "hashmap.h"
#include "dbug_mem.h"


int
chtbl_init(CHTbl *htbl, int buckets, int (*h)(const void *key), int
   (*match)(const void *obj1, const void *obj2), void (*destroy)(void *obj))
{
    int i;

    //MSG_DEBUG("chtbl_init() called");
    
    T_RDWR_INIT(&(htbl->rwlock), NULL);

    /* Allocate space for the hash table. */
    if ((htbl->table = (List *)malloc(buckets * sizeof(List))) == NULL)
        return -1;

    /* Initialize the buckets. */
    htbl->buckets = buckets;

    for (i = 0; i < htbl->buckets; i++) {
        list_init(&htbl->table[i], match, destroy);
    }

    /* Encapsulate the functions. */
    htbl->h = h;

    return 0;
}


void
chtbl_destroy(CHTbl *htbl)
{
    int i;

    //MSG_DEBUG("chtbl_destroy() called");
    
    T_RDWR_WLOCK(&(htbl->rwlock));

    /* Destroy each bucket. */
    for (i = 0; i < htbl->buckets; i++) {
        list_destroy(&htbl->table[i]);
    }
    
    /* Free the storage allocated for the hash table. */
    free(htbl->table);
    
    /* No operations are allowed now, but clear the structure as a precaution. */
    memset(htbl, 0, sizeof(CHTbl));
    
    T_RDWR_WUNLOCK(&(htbl->rwlock));

    return;
}


int
chtbl_size(CHTbl *htbl)
{
    int cnt = 0;
    int i;
    
    //MSG_DEBUG("chtbl_size() called");
    
    T_RDWR_RLOCK(&(htbl->rwlock));
    
    for (i = 0; i < htbl->buckets; i++) {
        cnt += list_getsize(&htbl->table[i]);
    }
    
    T_RDWR_RUNLOCK(&(htbl->rwlock));
    
    return cnt;
}


int
chtbl_insert(CHTbl *htbl, const void *data)
{
    void *temp;
    int bucket, retval;
     

    //MSG_DEBUG("chtbl_insert() called");
    
    /* Do nothing if the data is already in the table. */
    temp = (void *)data;
    
    T_RDWR_RLOCK(&(htbl->rwlock));

    /* Hash the key. */
    bucket = htbl->h(data) % htbl->buckets;
    
    /* Insert the data into the bucket. */
    retval = list_insert(&htbl->table[bucket], (void *)data);
    
    T_RDWR_RUNLOCK(&(htbl->rwlock));

    return retval;
}


int
chtbl_remove(CHTbl *htbl, void **data)
{
    int bucket;
    int retval = -1;
 
    //MSG_DEBUG("chtbl_remove() called");
    
    T_RDWR_RLOCK(&(htbl->rwlock));

    /* Hash the key. */
    bucket = htbl->h(*data) % htbl->buckets;
    
    /* Remove the data from the bucket. */
    retval = list_remove(&htbl->table[bucket], data);

    T_RDWR_RUNLOCK(&(htbl->rwlock));

    /* Return that the data was not found. */
    return retval;
}


int
chtbl_lookup(CHTbl *htbl, void **data)
{
    int bucket = 0;
    int retval = 0;
    
    //MSG_DEBUG("chtbl_lookup() called");
    
    T_RDWR_RLOCK(&(htbl->rwlock));

    /* Hash the key. */
    bucket = htbl->h(*data) % htbl->buckets;
    
    retval = list_lookup(&(htbl->table[bucket]), data);
    
    T_RDWR_RUNLOCK(&(htbl->rwlock));

    return retval;
}

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