summaryrefslogtreecommitdiff
path: root/hashmap.h
diff options
context:
space:
mode:
Diffstat (limited to 'hashmap.h')
-rw-r--r--hashmap.h91
1 files changed, 71 insertions, 20 deletions
diff --git a/hashmap.h b/hashmap.h
index b011b394fe..7251687d73 100644
--- a/hashmap.h
+++ b/hashmap.h
@@ -96,7 +96,7 @@
* }
*
* if (!strcmp("end", action)) {
- * hashmap_free_entries(&map, struct long2string, ent);
+ * hashmap_clear_and_free(&map, struct long2string, ent);
* break;
* }
* }
@@ -210,6 +210,9 @@ struct hashmap {
/* hashmap functions */
+#define HASHMAP_INIT(fn, data) { .cmpfn = fn, .cmpfn_data = data, \
+ .do_count_items = 1 }
+
/*
* Initializes a hashmap structure.
*
@@ -228,24 +231,72 @@ struct hashmap {
* prevent expensive resizing. If 0, the table is dynamically resized.
*/
void hashmap_init(struct hashmap *map,
- hashmap_cmp_fn equals_function,
- const void *equals_function_data,
- size_t initial_size);
+ hashmap_cmp_fn equals_function,
+ const void *equals_function_data,
+ size_t initial_size);
-/* internal function for freeing hashmap */
-void hashmap_free_(struct hashmap *map, ssize_t offset);
+/* internal functions for clearing or freeing hashmap */
+void hashmap_partial_clear_(struct hashmap *map, ssize_t offset);
+void hashmap_clear_(struct hashmap *map, ssize_t offset);
/*
- * Frees a hashmap structure and allocated memory, leaves entries undisturbed
+ * Frees a hashmap structure and allocated memory for the table, but does not
+ * free the entries nor anything they point to.
+ *
+ * Usage note:
+ *
+ * Many callers will need to iterate over all entries and free the data each
+ * entry points to; in such a case, they can free the entry itself while at it.
+ * Thus, you might see:
+ *
+ * hashmap_for_each_entry(map, hashmap_iter, e, hashmap_entry_name) {
+ * free(e->somefield);
+ * free(e);
+ * }
+ * hashmap_clear(map);
+ *
+ * instead of
+ *
+ * hashmap_for_each_entry(map, hashmap_iter, e, hashmap_entry_name) {
+ * free(e->somefield);
+ * }
+ * hashmap_clear_and_free(map, struct my_entry_struct, hashmap_entry_name);
+ *
+ * to avoid the implicit extra loop over the entries. However, if there are
+ * no special fields in your entry that need to be freed beyond the entry
+ * itself, it is probably simpler to avoid the explicit loop and just call
+ * hashmap_clear_and_free().
*/
-#define hashmap_free(map) hashmap_free_(map, -1)
+#define hashmap_clear(map) hashmap_clear_(map, -1)
/*
- * Frees @map and all entries. @type is the struct type of the entry
- * where @member is the hashmap_entry struct used to associate with @map
+ * Similar to hashmap_clear(), except that the table is no deallocated; it
+ * is merely zeroed out but left the same size as before. If the hashmap
+ * will be reused, this avoids the overhead of deallocating and
+ * reallocating map->table. As with hashmap_clear(), you may need to free
+ * the entries yourself before calling this function.
+ */
+#define hashmap_partial_clear(map) hashmap_partial_clear_(map, -1)
+
+/*
+ * Similar to hashmap_clear() but also frees all entries. @type is the
+ * struct type of the entry where @member is the hashmap_entry struct used
+ * to associate with @map.
+ *
+ * See usage note above hashmap_clear().
+ */
+#define hashmap_clear_and_free(map, type, member) \
+ hashmap_clear_(map, offsetof(type, member))
+
+/*
+ * Similar to hashmap_partial_clear() but also frees all entries. @type is
+ * the struct type of the entry where @member is the hashmap_entry struct
+ * used to associate with @map.
+ *
+ * See usage note above hashmap_clear().
*/
-#define hashmap_free_entries(map, type, member) \
- hashmap_free_(map, offsetof(type, member));
+#define hashmap_partial_clear_and_free(map, type, member) \
+ hashmap_partial_clear_(map, offsetof(type, member))
/* hashmap_entry functions */
@@ -261,7 +312,7 @@ void hashmap_free_(struct hashmap *map, ssize_t offset);
* and if it is on stack, you can just let it go out of scope).
*/
static inline void hashmap_entry_init(struct hashmap_entry *e,
- unsigned int hash)
+ unsigned int hash)
{
e->hash = hash;
e->next = NULL;
@@ -303,8 +354,8 @@ static inline unsigned int hashmap_get_size(struct hashmap *map)
* to `hashmap_cmp_fn` to decide whether the entry matches the key.
*/
struct hashmap_entry *hashmap_get(const struct hashmap *map,
- const struct hashmap_entry *key,
- const void *keydata);
+ const struct hashmap_entry *key,
+ const void *keydata);
/*
* Returns the hashmap entry for the specified hash code and key data,
@@ -337,7 +388,7 @@ static inline struct hashmap_entry *hashmap_get_from_hash(
* call to `hashmap_get` or `hashmap_get_next`.
*/
struct hashmap_entry *hashmap_get_next(const struct hashmap *map,
- const struct hashmap_entry *entry);
+ const struct hashmap_entry *entry);
/*
* Adds a hashmap entry. This allows to add duplicate entries (i.e.
@@ -357,7 +408,7 @@ void hashmap_add(struct hashmap *map, struct hashmap_entry *entry);
* Returns the replaced entry, or NULL if not found (i.e. the entry was added).
*/
struct hashmap_entry *hashmap_put(struct hashmap *map,
- struct hashmap_entry *entry);
+ struct hashmap_entry *entry);
/*
* Adds or replaces a hashmap entry contained within @keyvar,
@@ -379,8 +430,8 @@ struct hashmap_entry *hashmap_put(struct hashmap *map,
* Argument explanation is the same as in `hashmap_get`.
*/
struct hashmap_entry *hashmap_remove(struct hashmap *map,
- const struct hashmap_entry *key,
- const void *keydata);
+ const struct hashmap_entry *key,
+ const void *keydata);
/*
* Removes a hashmap entry contained within @keyvar,
@@ -422,7 +473,7 @@ struct hashmap_entry *hashmap_iter_next(struct hashmap_iter *iter);
/* Initializes the iterator and returns the first entry, if any. */
static inline struct hashmap_entry *hashmap_iter_first(struct hashmap *map,
- struct hashmap_iter *iter)
+ struct hashmap_iter *iter)
{
hashmap_iter_init(map, iter);
return hashmap_iter_next(iter);