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/*
* This file is part of NetSurf, http://netsurf.sourceforge.net/
* Licensed under the GNU General Public License,
* http://www.opensource.org/licenses/gpl-license
* Copyright 2006 Rob Kendrick <rjek@rjek.com>
*/
/** Write-Once hash table for string to string mappings */
#include <stdlib.h>
#include <string.h>
#ifdef TEST_RIG
#include <assert.h>
#include <stdio.h>
#endif
#include "netsurf/utils/hashtable.h"
#include "netsurf/utils/log.h"
struct hash_table *hash_create(unsigned int chains)
{
struct hash_table *r = (struct hash_table *)malloc(
sizeof(struct hash_table));
if (r == NULL) {
LOG(("Not enough memory for hash table."));
return NULL;
}
r->nchains = chains;
r->chain = (struct hash_entry **)
calloc(chains, sizeof(struct hash_entry));
if (r->chain == NULL) {
LOG(("Not enough memory for %d hash table chains.", chains));
free(r);
return NULL;
}
return r;
}
void hash_destroy(struct hash_table *ht)
{
int i;
for (i = 0; i < ht->nchains; i++) {
if (ht->chain[i] != NULL) {
struct hash_entry *e = ht->chain[i];
while (e) {
struct hash_entry *n = e->next;
free(e->key);
free(e->value);
free(e);
e = n;
}
}
}
free(ht->chain);
free(ht);
}
void hash_add(struct hash_table *ht, const char *key, const char *value)
{
unsigned int h = hash_string_fnv(key);
unsigned int c = h % ht->nchains;
struct hash_entry *e = (struct hash_entry *)malloc(
sizeof(struct hash_entry));
e->key = strdup(key);
e->value = strdup(value);
e->next = ht->chain[c];
ht->chain[c] = e;
}
const char *hash_get(struct hash_table *ht, const char *key)
{
unsigned int h = hash_string_fnv(key);
unsigned int c = h % ht->nchains;
struct hash_entry *e = ht->chain[c];
while (e) {
if (!strcmp(key, e->key))
return e->value;
e = e->next;
}
return NULL;
}
unsigned int hash_string_fnv(const char *datum)
{
unsigned int z = 0x01000193, i = 0;
while (datum[i]) {
z *= 0x01000193;
z ^= datum[i];
datum++;
}
return z;
}
#ifdef TEST_RIG
int main(int argc, char *argv[])
{
struct hash_table *a, *b;
FILE *dict;
char keybuf[BUFSIZ], valbuf[BUFSIZ];
a = hash_create(79);
assert(a != NULL);
b = hash_create(103);
assert(b != NULL);
hash_add(a, "cow", "moo");
hash_add(b, "moo", "cow");
hash_add(a, "pig", "oink");
hash_add(b, "oink", "pig");
hash_add(a, "chicken", "cluck");
hash_add(b, "cluck", "chicken");
hash_add(a, "dog", "woof");
hash_add(b, "woof", "dog");
hash_add(a, "cat", "meow");
hash_add(b, "meow", "cat");
#define MATCH(x,y) assert(!strcmp(hash_get(a, x), y)); assert(!strcmp(hash_get(b, y), x))
MATCH("cow", "moo");
MATCH("pig", "oink");
MATCH("chicken", "cluck");
MATCH("dog", "woof");
MATCH("cat", "meow");
hash_destroy(a);
hash_destroy(b);
/* this test requires /usr/share/dict/words - a large list of English
* words. We load the entire file - odd lines are used as keys, and
* even lines are used as the values for the previous line. we then
* work through it again making sure everything matches.
*
* We do this twice - once in a hash table with many chains, and once
* with a hash table with fewer chains.
*/
a = hash_create(1031);
b = hash_create(7919);
dict = fopen("/usr/share/dict/words", "r");
if (dict == NULL) {
fprintf(stderr, "Unable to open /usr/share/dict/words - extensive testing skipped.\n");
exit(0);
}
while (!feof(dict)) {
fscanf(dict, "%s", keybuf);
fscanf(dict, "%s", valbuf);
hash_add(a, keybuf, valbuf);
hash_add(b, keybuf, valbuf);
}
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);
}
hash_destroy(a);
hash_destroy(b);
fclose(dict);
return 0;
}
#endif
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