110 lines
2.8 KiB
C
110 lines
2.8 KiB
C
/* hash table */
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#include <stdio.h>
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#include <stdlib.h>
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#include "hash.h"
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#include "iftop.h"
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hash_status_enum hash_insert(hash_type* hash_table, void* key, void* rec) {
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hash_node_type *p, *p0;
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int bucket;
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/************************************************
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* allocate node for data and insert in table *
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************************************************/
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/* insert node at beginning of list */
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bucket = hash_table->hash(key);
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p = xmalloc(sizeof *p);
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p0 = hash_table->table[bucket];
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hash_table->table[bucket] = p;
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p->next = p0;
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p->key = hash_table->copy_key(key);
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p->rec = rec;
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return HASH_STATUS_OK;
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}
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hash_status_enum hash_delete(hash_type* hash_table, void* key) {
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hash_node_type *p0, *p;
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int bucket;
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/********************************************
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* delete node containing data from table *
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********************************************/
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/* find node */
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p0 = 0;
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bucket = hash_table->hash(key);
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p = hash_table->table[bucket];
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while (p && !hash_table->compare(p->key, key)) {
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p0 = p;
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p = p->next;
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}
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if (!p) return HASH_STATUS_KEY_NOT_FOUND;
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/* p designates node to delete, remove it from list */
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if (p0)
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/* not first node, p0 points to previous node */
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p0->next = p->next;
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else
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/* first node on chain */
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hash_table->table[bucket] = p->next;
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hash_table->delete_key(p->key);
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free (p);
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return HASH_STATUS_OK;
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}
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hash_status_enum hash_find(hash_type* hash_table, void* key, void **rec) {
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hash_node_type *p;
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/*******************************
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* find node containing data *
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*******************************/
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p = hash_table->table[hash_table->hash(key)];
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while (p && !hash_table->compare(p->key, key))
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p = p->next;
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if (!p) return HASH_STATUS_KEY_NOT_FOUND;
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*rec = p->rec;
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return HASH_STATUS_OK;
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}
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hash_status_enum hash_next_item(hash_type* hash_table, hash_node_type** ppnode) {
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int i;
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if(*ppnode != NULL) {
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if((*ppnode)->next != NULL) {
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*ppnode = (*ppnode)->next;
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return HASH_STATUS_OK;
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}
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i = hash_table->hash((*ppnode)->key) + 1;
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}
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else {
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/* first node */
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i = 0;
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}
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while(i < hash_table->size && hash_table->table[i] == NULL) {
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i++;
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}
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if(i == hash_table->size) {
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*ppnode = NULL;
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return HASH_STATUS_KEY_NOT_FOUND;
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}
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*ppnode = hash_table->table[i];
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return HASH_STATUS_OK;
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}
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/*
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* Allocate and return a hash
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*/
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hash_status_enum hash_initialise(hash_type* hash_table) {
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hash_table->table = xcalloc(hash_table->size, sizeof *hash_table->table);
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return HASH_STATUS_OK;
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}
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hash_status_enum hash_destroy(hash_type* hash_table) {
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free(hash_table->table);
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return HASH_STATUS_OK;
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}
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