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/* the Music Player Daemon (MPD)
* Copyright (C) 2008 Max Kellermann <max@duempel.org>
* This project's homepage is: http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "strset.h"
#include "utils.h"
#include "os_compat.h"
#define NUM_SLOTS 16384
struct strset_slot {
struct strset_slot *next;
const char *value;
};
struct strset {
unsigned size;
struct strset_slot *current_slot;
unsigned next_slot;
struct strset_slot slots[NUM_SLOTS];
};
static unsigned calc_hash(const char *p) {
unsigned hash = 5381;
assert(p != NULL);
while (*p != 0)
hash = (hash << 5) + hash + *p++;
return hash;
}
mpd_malloc struct strset *strset_new(void)
{
struct strset *set = xcalloc(1, sizeof(*set));
return set;
}
void strset_free(struct strset *set)
{
unsigned i;
for (i = 0; i < NUM_SLOTS; ++i) {
struct strset_slot *slot = set->slots[i].next, *next;
while (slot != NULL) {
next = slot->next;
free(slot);
slot = next;
}
}
free(set);
}
void strset_add(struct strset *set, const char *value)
{
struct strset_slot *base_slot
= &set->slots[calc_hash(value) % NUM_SLOTS];
struct strset_slot *slot = base_slot;
if (base_slot->value == NULL) {
/* empty slot - put into base_slot */
assert(base_slot->next == NULL);
base_slot->value = value;
++set->size;
return;
}
for (slot = base_slot->next; slot != NULL; slot = slot->next)
if (strcmp(slot->value, value) == 0)
/* found it - do nothing */
return;
/* insert it into the slot chain */
slot = xmalloc(sizeof(*slot));
slot->next = base_slot->next;
slot->value = value;
base_slot->next = slot;
++set->size;
}
int strset_get(const struct strset *set, const char *value)
{
const struct strset_slot *slot = &set->slots[calc_hash(value)];
if (slot->value == NULL)
return 0;
for (slot = slot->next; slot != NULL; slot = slot->next)
if (strcmp(slot->value, value) == 0)
/* found it - do nothing */
return 1;
return 0;
}
unsigned strset_size(const struct strset *set)
{
return set->size;
}
void strset_rewind(struct strset *set)
{
set->current_slot = NULL;
set->next_slot = 0;
}
const char *strset_next(struct strset *set)
{
if (set->current_slot != NULL && set->current_slot->next != NULL) {
set->current_slot = set->current_slot->next;
return set->current_slot->value;
}
while (set->next_slot < NUM_SLOTS &&
set->slots[set->next_slot].value == NULL)
++set->next_slot;
if (set->next_slot >= NUM_SLOTS)
return NULL;
set->current_slot = &set->slots[set->next_slot++];
return set->current_slot->value;
}
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