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-rw-r--r--src/strset.c144
1 files changed, 144 insertions, 0 deletions
diff --git a/src/strset.c b/src/strset.c
new file mode 100644
index 000000000..475266370
--- /dev/null
+++ b/src/strset.c
@@ -0,0 +1,144 @@
+/* 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; 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;
+}
+