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Further hash table optimisations and tidies. Test rig now does more lookups to favour the more comment case for speed tests, etc. 

svn path=/trunk/netsurf/; revision=3003
This commit is contained in:
Rob Kendrick 2006-10-13 15:50:11 +00:00
parent a8a944bd52
commit 7711781f24
2 changed files with 19 additions and 14 deletions
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31
utils/hashtable.c
View File

@ -123,7 +123,7 @@ bool hash_add(struct hash_table *ht, const char *key, const char *value)
return false;
}
h = hash_string_fnv(key);
h = hash_string_fnv(key, &(e->key_length));
c = h % ht->nchains;
e->key = strdup(key);
@ -141,7 +141,6 @@ bool hash_add(struct hash_table *ht, const char *key, const char *value)
return false;
}
e->key_length = strlen(key);
e->next = ht->chain[c];
ht->chain[c] = e;
@ -166,12 +165,12 @@ const char *hash_get(struct hash_table *ht, const char *key)
if (ht == NULL || key == NULL)
return NULL;
h = hash_string_fnv(key);
h = hash_string_fnv(key, &key_length);
c = h % ht->nchains;
key_length = strlen(key);
for (e = ht->chain[c]; e; e = e->next)
if ((key_length == e->key_length) && (!strcmp(key, e->key)))
if ((key_length == e->key_length) &&
(memcmp(key, e->key, key_length) == 0))
return e->value;
return NULL;
@ -184,12 +183,14 @@ const char *hash_get(struct hash_table *ht, const char *key)
* See http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash for more details.
*
* \param datum The string to hash.
* \param len Pointer to unsigned integer to record datum's length in.
* \return The calculated hash value for the datum.
*/
unsigned int hash_string_fnv(const char *datum)
unsigned int hash_string_fnv(const char *datum, unsigned int *len)
{
unsigned int z = 0x01000193;
*len = 0;
if (datum == NULL)
return 0;
@ -197,6 +198,7 @@ unsigned int hash_string_fnv(const char *datum)
while (*datum) {
z *= 0x01000193;
z ^= *datum++;
(*len)++;
}
return z;
@ -207,7 +209,7 @@ unsigned int hash_string_fnv(const char *datum)
*
* If you make changes to this hash table implementation, please rerun this
* test, and if possible, through valgrind to make sure there are no memory
* leaks or invalid memory accesses.. If you add new functionality, please
* leaks or invalid memory accesses. If you add new functionality, please
* include a test for it that has good coverage along side the other tests.
*/
@ -218,6 +220,7 @@ int main(int argc, char *argv[])
struct hash_table *a, *b;
FILE *dict;
char keybuf[BUFSIZ], valbuf[BUFSIZ];
int i;
a = hash_create(79);
assert(a != NULL);
@ -275,13 +278,15 @@ int main(int argc, char *argv[])
hash_add(b, keybuf, valbuf);
}
fseek(dict, 0, SEEK_SET);
for (i = 0; i < 5; i++) {
fseek(dict, 0, SEEK_SET);
while (!feof(dict)) {
fscanf(dict, "%s", keybuf);
fscanf(dict, "%s", valbuf);
assert(strcmp(hash_get(a, keybuf), valbuf) == 0);
assert(strcmp(hash_get(b, keybuf), valbuf) == 0);
while (!feof(dict)) {
fscanf(dict, "%s", keybuf);
fscanf(dict, "%s", valbuf);
assert(strcmp(hash_get(a, keybuf), valbuf) == 0);
assert(strcmp(hash_get(b, keybuf), valbuf) == 0);
}
}
hash_destroy(a);

2
utils/hashtable.h
View File

@ -19,6 +19,6 @@ struct hash_table *hash_create(unsigned int chains);
void hash_destroy(struct hash_table *ht);
bool hash_add(struct hash_table *ht, const char *key, const char *value);
const char *hash_get(struct hash_table *ht, const char *key);
unsigned int hash_string_fnv(const char *datum);
unsigned int hash_string_fnv(const char *datum, unsigned int *len);
#endif