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mirror of https://github.com/moparisthebest/curl synced 2024-11-08 18:45:05 -05:00
curl/lib/hash.c
Daniel Stenberg fb5f332834 - Constantine Sapuntzakis posted bug #2891595
(http://curl.haxx.se/bug/view.cgi?id=2891595) which identified how an entry
  in the DNS cache would linger too long if the request that added it was in
  use that long. He also provided the patch that now makes libcurl capable of
  still doing a request while the DNS hash entry may get timed out.
2009-11-11 09:31:37 +00:00

341 lines
7.7 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2009, 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"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
#include "curl_memory.h"
/* The last #include file should be: */
#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);
if(e->ptr)
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 = 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 = 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(const void *key, size_t key_len, const void *p)
{
struct curl_hash_element *he = malloc(sizeof(struct curl_hash_element));
if(he) {
void *dupkey = malloc(key_len);
if(dupkey) {
/* copy the key */
memcpy(dupkey, key, key_len);
he->key = dupkey;
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)]
/* Insert the data in the hash. If there already was a match in the hash,
that data is replaced. */
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)) {
Curl_llist_remove(l, le, (void *)h);
--h->size;
break;
}
}
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(DEBUGBUILD) && 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);
h->table[i] = NULL;
}
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)
{
const char* key_str = (const char *) key;
const char *end = 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