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/* hash.c - hash tables for ipkg
Steven M. Ayer, Jamey Hicks
Copyright (C) 2002 Compaq Computer Corporation
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "hash_table.h"
#include "ipkg_message.h"
static int hash_index(hash_table_t *hash, const char *pkg_name);
static int rotating(const char *key, int len, int prime);
static int hash_index(hash_table_t *hash, const char *pkg_name)
{
return rotating(pkg_name, strlen(pkg_name), hash->n_entries);
}
static int rotating(const char *key, int len, int prime)
{
unsigned int hash, i;
for (hash=len, i=0; i<len; ++i)
hash = (hash<<4)^(hash>>28)^key[i];
return (hash % prime);
}
/*
* this is an open table keyed by strings
*/
int hash_table_init(const char *name, hash_table_t *hash, int len)
{
static int primes_table[] = {
379, 761, 983, 1423, 2711, 3361, 3931, 4679, 5519, 6701, 9587,
19471, 23143, 33961, 46499, 49727, 99529, 0
};
int *picker;
if (hash->entries != NULL) {
/* we have been here already */
return 0;
}
hash->name = name;
hash->entries = NULL;
hash->n_entries = 0;
hash->hash_entry_key = NULL;
picker = primes_table;
while(*picker && (*picker++ < len));
if(!*picker)
fprintf(stderr, "%s: primes table might not be big enough (! << %d)\n", __FUNCTION__, len);
--picker;
hash->n_entries = *picker;
hash->entries = (hash_entry_t *)calloc(hash->n_entries, sizeof(hash_entry_t));
if (hash->entries == NULL) {
fprintf(stderr, "%s: Out of memory.\n", __FUNCTION__);
return ENOMEM;
}
return 0;
}
void hash_table_deinit(hash_table_t *hash)
{
free(hash->entries);
hash->entries = NULL;
hash->n_entries = 0;
}
void *hash_table_get(hash_table_t *hash, const char *key)
{
int ndx= hash_index(hash, key);
hash_entry_t *hash_entry = hash->entries + ndx;
while (hash_entry)
{
if (hash_entry->key)
{
if (strcmp(key, hash_entry->key) == 0) {
// ipkg_message(NULL, IPKG_DEBUG, "Function: %s. Key found for '%s' \n", __FUNCTION__, key);
return hash_entry->data;
}
}
hash_entry = hash_entry->next;
}
return NULL;
}
int hash_table_insert(hash_table_t *hash, const char *key, void *value)
{
int ndx= hash_index(hash, key);
hash_entry_t *hash_entry = hash->entries + ndx;
if (0) ipkg_message(NULL, IPKG_DEBUG2, "Function: %s. Inserting in hash for '%s' \n", __FUNCTION__, key);
if (hash_entry->key) {
if (strcmp(hash_entry->key, key) == 0) {
/* alread in table, update the value */
if (0) ipkg_message(NULL, IPKG_DEBUG2, "Function: %s. Value already in hash for '%s' \n", __FUNCTION__, key);
hash_entry->data = value;
return 0;
} else {
/*
* if this is a collision, we have to go to the end of the ll,
* then add a new entry
* before we can hook up the value
*/
if (0) ipkg_message(NULL, IPKG_DEBUG2, "Function: %s. Value already in hash by collision for '%s' \n", __FUNCTION__, key);
while (hash_entry->next)
hash_entry = hash_entry->next;
hash_entry->next = (hash_entry_t *)malloc(sizeof(hash_entry_t));
if (!hash_entry->next) {
return -ENOMEM;
}
hash_entry = hash_entry->next;
hash_entry->next = NULL;
}
}
hash->n_elements++;
hash_entry->key = strdup(key);
hash_entry->data = value;
return 0;
}
void hash_table_foreach(hash_table_t *hash, void (*f)(const char *key, void *entry, void *data), void *data)
{
int i;
if (!hash || !f)
return;
for (i = 0; i < hash->n_entries; i++) {
hash_entry_t *hash_entry = (hash->entries + i);
do {
if(hash_entry->key) {
f(hash_entry->key, hash_entry->data, data);
}
} while((hash_entry = hash_entry->next));
}
}
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