support multiple objects sharing the same name

1 files changed, 65 insertions, 0 deletions

diff --git a/src/multimap.h b/src/multimap.h
new file mode 100644
index 0000000..8faa829
--- /dev/null
+++ b/src/multimap.h
@@ -0,0 +1,65 @@
+/*
+ *   NetCosm - a MUD server
+ *   Copyright (C) 2016 Franklin Wei
+ *
+ *   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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "hash.h"
+
+/* a multimap implemented as a hash of linked lists */
+/* O(1) insertion and lookup */
+/* O(n) deletion by value, O(1) deletion by key */
+
+/* there can be both duplicate keys AND values */
+
+void *multimap_init(size_t tabsz,
+                    unsigned (*hash_fn)(const void *key),
+                    int (*compare_key)(const void *key_a, const void *key_b),
+                    int (*compare_val)(const void *val_a, const void *val_b));
+
+void multimap_free(void*);
+
+struct multimap_list {
+    const void *key;
+    void *val;
+    struct multimap_list *next;
+};
+
+/* returns a linked list of values with the same key with the length in n_pairs */
+const struct multimap_list *multimap_lookup(void *map, const void *key, size_t *n_pairs);
+
+/* returns true if there was no other pair with the same key */
+bool multimap_insert(void *map, const void *key, const void *val);
+
+/* delete the pair(s) with the given key and value, returns # deleted */
+size_t multimap_delete(void *map, const void *key, const void *val);
+
+/* returns # deleted */
+size_t multimap_delete_all(void *map, const void *key);
+
+/* returns a linked list, NOT individual items of a linked list */
+/* set map to NULL after the initial call */
+const struct multimap_list *multimap_iterate(void *map, void **save, size_t *n_pairs);
+
+size_t multimap_size(void *map);
+
+void multimap_setfreedata_cb(void *map, void (*)(void*));
+
+void multimap_free(void *ptr);
+void *multimap_dup(void *ptr);
+void multimap_setdupdata_cb(void *ptr, void *(*cb)(void *ptr));
+void *multimap_copy(void *ptr);