curl/lib/hash.c
Daniel Stenberg 62f0f5571d Robert Iakobashvili re-arranged the internal hash code to work with a custom
hash function for different hashes, and also expanded the default size for
the socket hash table used in multi handles to greatly enhance speed when
very many connections are added and the socket API is used.
2007-06-26 21:09:28 +00:00

335 lines
7.7 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* $Id$
***************************************************************************/
#include "setup.h"
#include <string.h>
#include <stdlib.h>
#include "hash.h"
#include "llist.h"
#include "memory.h"
/* this must be the last include file */
#include "memdebug.h"
static void
hash_element_dtor(void *user, void *element)
{
struct curl_hash *h = (struct curl_hash *) user;
struct curl_hash_element *e = (struct curl_hash_element *) element;
if (e->key)
free(e->key);
h->dtor(e->ptr);
free(e);
}
/* return 1 on error, 0 is fine */
int
Curl_hash_init(struct curl_hash *h,
int slots,
hash_function hfunc,
comp_function comparator,
curl_hash_dtor dtor)
{
int i;
if (!slots || !hfunc || !comparator ||!dtor) {
return 1; /* failure */
}
h->hash_func = hfunc;
h->comp_func = comparator;
h->dtor = dtor;
h->size = 0;
h->slots = slots;
h->table = (struct curl_llist **) malloc(slots * sizeof(struct curl_llist *));
if(h->table) {
for (i = 0; i < slots; ++i) {
h->table[i] = Curl_llist_alloc((curl_llist_dtor) hash_element_dtor);
if(!h->table[i]) {
while(i--)
Curl_llist_destroy(h->table[i], NULL);
free(h->table);
return 1; /* failure */
}
}
return 0; /* fine */
}
else
return 1; /* failure */
}
struct curl_hash *
Curl_hash_alloc(int slots,
hash_function hfunc,
comp_function comparator,
curl_hash_dtor dtor)
{
struct curl_hash *h;
if (!slots || !hfunc || !comparator ||!dtor) {
return NULL; /* failure */
}
h = (struct curl_hash *) malloc(sizeof(struct curl_hash));
if (h) {
if(Curl_hash_init(h, slots, hfunc, comparator, dtor)) {
/* failure */
free(h);
h = NULL;
}
}
return h;
}
static struct curl_hash_element *
mk_hash_element(void *key, size_t key_len, const void *p)
{
struct curl_hash_element *he =
(struct curl_hash_element *) malloc(sizeof(struct curl_hash_element));
if(he) {
void *dup = malloc(key_len);
if(dup) {
/* copy the key */
memcpy(dup, key, key_len);
he->key = dup;
he->key_len = key_len;
he->ptr = (void *) p;
}
else {
/* failed to duplicate the key, free memory and fail */
free(he);
he = NULL;
}
}
return he;
}
#define FETCH_LIST(x,y,z) x->table[x->hash_func(y, z, x->slots)]
/* Return the data in the hash. If there already was a match in the hash,
that data is returned. */
void *
Curl_hash_add(struct curl_hash *h, void *key, size_t key_len, void *p)
{
struct curl_hash_element *he;
struct curl_llist_element *le;
struct curl_llist *l = FETCH_LIST (h, key, key_len);
for (le = l->head; le; le = le->next) {
he = (struct curl_hash_element *) le->ptr;
if (h->comp_func(he->key, he->key_len, key, key_len)) {
h->dtor(p); /* remove the NEW entry */
return he->ptr; /* return the EXISTING entry */
}
}
he = mk_hash_element(key, key_len, p);
if (he) {
if(Curl_llist_insert_next(l, l->tail, he)) {
++h->size;
return p; /* return the new entry */
}
/*
* Couldn't insert it, destroy the 'he' element and the key again. We
* don't call hash_element_dtor() since that would also call the
* "destructor" for the actual data 'p'. When we fail, we shall not touch
* that data.
*/
free(he->key);
free(he);
}
return NULL; /* failure */
}
/* remove the identified hash entry, returns non-zero on failure */
int Curl_hash_delete(struct curl_hash *h, void *key, size_t key_len)
{
struct curl_llist_element *le;
struct curl_hash_element *he;
struct curl_llist *l = FETCH_LIST(h, key, key_len);
for (le = l->head; le; le = le->next) {
he = le->ptr;
if (h->comp_func(he->key, he->key_len, key, key_len)) {
Curl_llist_remove(l, le, (void *) h);
return 0;
}
}
return 1;
}
void *
Curl_hash_pick(struct curl_hash *h, void *key, size_t key_len)
{
struct curl_llist_element *le;
struct curl_hash_element *he;
struct curl_llist *l = FETCH_LIST(h, key, key_len);
for (le = l->head; le; le = le->next) {
he = le->ptr;
if (h->comp_func(he->key, he->key_len, key, key_len)) {
return he->ptr;
}
}
return NULL;
}
#if defined(CURLDEBUG) && defined(AGGRESIVE_TEST)
void
Curl_hash_apply(curl_hash *h, void *user,
void (*cb)(void *user, void *ptr))
{
struct curl_llist_element *le;
int i;
for (i = 0; i < h->slots; ++i) {
for (le = (h->table[i])->head;
le;
le = le->next) {
curl_hash_element *el = le->ptr;
cb(user, el->ptr);
}
}
}
#endif
void
Curl_hash_clean(struct curl_hash *h)
{
int i;
for (i = 0; i < h->slots; ++i) {
Curl_llist_destroy(h->table[i], (void *) h);
}
free(h->table);
}
void
Curl_hash_clean_with_criterium(struct curl_hash *h, void *user,
int (*comp)(void *, void *))
{
struct curl_llist_element *le;
struct curl_llist_element *lnext;
struct curl_llist *list;
int i;
for (i = 0; i < h->slots; ++i) {
list = h->table[i];
le = list->head; /* get first list entry */
while(le) {
struct curl_hash_element *he = le->ptr;
lnext = le->next;
/* ask the callback function if we shall remove this entry or not */
if (comp(user, he->ptr)) {
Curl_llist_remove(list, le, (void *) h);
--h->size; /* one less entry in the hash now */
}
le = lnext;
}
}
}
void
Curl_hash_destroy(struct curl_hash *h)
{
if (!h)
return;
Curl_hash_clean(h);
free(h);
}
size_t Curl_hash_str(void* key, size_t key_length, size_t slots_num)
{
char* key_str = (char *) key;
char *end = (char *) key_str + key_length;
unsigned long h = 5381;
while (key_str < end) {
h += h << 5;
h ^= (unsigned long) *key_str++;
}
return (h % slots_num);
}
size_t Curl_str_key_compare(void*k1, size_t key1_len, void*k2, size_t key2_len)
{
char *key1 = (char *)k1;
char *key2 = (char *)k2;
if (key1_len == key2_len &&
*key1 == *key2 &&
memcmp(key1, key2, key1_len) == 0) {
return 1;
}
return 0;
}
#if 0 /* useful function for debugging hashes and their contents */
void Curl_hash_print(struct curl_hash *h,
void (*func)(void *))
{
int i;
struct curl_llist_element *le;
struct curl_llist *list;
struct curl_hash_element *he;
if (!h)
return;
fprintf(stderr, "=Hash dump=\n");
for (i = 0; i < h->slots; i++) {
list = h->table[i];
le = list->head; /* get first list entry */
if(le) {
fprintf(stderr, "index %d:", i);
while(le) {
he = le->ptr;
if(func)
func(he->ptr);
else
fprintf(stderr, " [%p]", he->ptr);
le = le->next;
}
fprintf(stderr, "\n");
}
}
}
#endif