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Thanks to Justin Guyett for making the hashmap_insert() function use a

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constant time insert.  Explanation: new enteries are added to the _front_
of the chain, rather than search to the end.
This commit is contained in:
Robert James Kaes 2002-05-13 20:02:23 +00:00
parent 73e3b495e0
commit 16e96c79e8
2 changed files with 19 additions and 28 deletions
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2
ChangeLog
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@ -5,6 +5,8 @@
(hashmap_remove): Fixed a problem where an entry could have it's
"prev" pointer still pointing at freed memory. Thanks to Justin
Guyett for finding and fixing this problem.
(hashmap_insert): Thanks to Justin Guyett for changing the code to
use a constant time insert. Much cleaner _and_ faster.
2002-05-10 Robert James Kaes <rjkaes@flarenet.com>

45
src/hashmap.c
View File

@ -1,4 +1,4 @@
/* $Id: hashmap.c,v 1.8 2002-05-13 18:47:46 rjkaes Exp $
/* $Id: hashmap.c,v 1.9 2002-05-13 20:02:23 rjkaes Exp $
*
* A hashmap implementation. The keys are case-insensitive NULL terminated
* strings, and the data is arbitrary lumps of data. Copies of both the
@ -185,7 +185,7 @@ int
hashmap_insert(hashmap_t map, const char *key,
const void *data, size_t len)
{
struct hashentry_s *ptr, *prevptr;
struct hashentry_s *ptr;
int hash;
char *key_copy;
void *data_copy;
@ -223,40 +223,29 @@ hashmap_insert(hashmap_t map, const char *key,
data_copy = NULL;
}
ptr = map->buckets[hash];
if (ptr) {
/* There is already an entry, so tack onto the end */
while (ptr) {
prevptr = ptr;
ptr = ptr->next;
}
ptr = safecalloc(1, sizeof(struct hashentry_s));
if (!ptr)
goto MEM_ERROR_EXIT;
ptr->prev = prevptr;
ptr->next = NULL;
prevptr->next = ptr;
} else {
ptr = map->buckets[hash] = safecalloc(1, sizeof(struct hashentry_s));
if (!ptr)
goto MEM_ERROR_EXIT;
ptr->next = ptr->prev = NULL;
ptr = safemalloc(sizeof(struct hashentry_s));
if (!ptr) {
safefree(key_copy);
safefree(data_copy);
return -ENOMEM;
}
ptr->key = key_copy;
ptr->data = data_copy;
ptr->len = len;
/*
* Put the entry at the beginning of the chain. This is a constant
* time insert. Thanks to Justin Guyett for the code.
*/
ptr->prev = NULL;
ptr->next = map->buckets[hash];
map->buckets[hash] = ptr;
if (ptr->next)
ptr->next->prev = ptr;
map->end_iterator++;
return 0;
MEM_ERROR_EXIT:
safefree(key_copy);
safefree(data_copy);
return -ENOMEM;
}
/*