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qbmap.h(3) | libqb | qbmap.h(3) |
NAME¶
qbmap.h - This provides a map interface to a Patricia trie, hashtable or skiplist.SYNOPSIS¶
#include <stdint.h>Defines¶
#define QB_MAP_NOTIFY_DELETED 1
Typedefs¶
typedef struct qb_map qb_map_t
Functions¶
qb_map_t * qb_hashtable_create (size_t max_size)
Detailed Description¶
This provides a map interface to a Patricia trie, hashtable or skiplist. OrderingThe hashtable is NOT ordered, but ptrie and skiplist
are.
Iterating
Below is a simple example of how to iterate over a map.
Deletion of items within the iterator is supported. But note do not free the
item memory in the iterator. If you need to free the data items then register
for a notifier and free the memory there. This is required as the items are
reference counted.
const char *p; void *data; qb_map_iter_t *it = qb_map_iter_create(m); for (p = qb_map_iter_next(it, &data); p; p = qb_map_iter_next(it, &data)) { printf('%s > %s0, p, (char*) data); } qb_map_iter_free(it);
qb_map_notify_add(m, NULL, my_map_free_handler, QB_MAP_NOTIFY_FREE, NULL);Notifications
These allow you to get callbacks when values are
inserted/removed or replaced.
Note:
hashtable only supports deletion and replacement
notificatins. There is also a special global callback for freeing deleted and
replaced values (QB_MAP_NOTIFY_FREE).
See also:
qb_map_notify_add()
qb_map_notify_del_2()
Prefix matching
The ptrie supports prefixes in the iterator:
it = qb_map_pref_iter_create(m, 'aa'); while ((p = qb_map_iter_next(it, &data)) != NULL) { printf('%s > %s0, p, (char*)data); } qb_map_iter_free(it);The ptrie also supports prefixes in notifications: (remember to pass QB_MAP_NOTIFY_RECURSIVE into the notify_add.
qb_map_notify_add(m, 'root', my_map_notification, (QB_MAP_NOTIFY_INSERTED| QB_MAP_NOTIFY_DELETED| QB_MAP_NOTIFY_REPLACED| QB_MAP_NOTIFY_RECURSIVE), NULL);
Define Documentation¶
#define QB_MAP_NOTIFY_DELETED 1¶
#define QB_MAP_NOTIFY_FREE 16¶
#define QB_MAP_NOTIFY_INSERTED 4¶
#define QB_MAP_NOTIFY_RECURSIVE 8¶
#define QB_MAP_NOTIFY_REPLACED 2¶
Typedef Documentation¶
typedef struct qb_map_iter qb_map_iter_t¶
This is an opaque data type representing an iterator instance.typedef void(* qb_map_notify_fn)(uint32_t event, char *key, void *old_value, void *value, void *user_data)¶
typedef struct qb_map qb_map_t¶
This is an opaque data type representing an instance of a map.typedef int32_t(* qb_map_transverse_fn)(const char *key, void *value, void *user_data)¶
Function Documentation¶
qb_map_t* qb_hashtable_create (size_tmax_size)¶
Create an unsorted map based on a hashtable. Parameters:max_size maximum size of the hashtable
Returns:
the map instance
size_t qb_map_count_get (qb_map_t *map)¶
Get the number of items in the map.void qb_map_destroy (qb_map_t *map)¶
Destroy the map, removes all the items from the map.void qb_map_foreach (qb_map_t *map, qb_map_transverse_fnfunc, void *user_data)¶
Calls the given function for each of the key/value pairs in the map. The function is passed the key and value of each pair, and the given data parameter. The map is traversed in sorted order.void* qb_map_get (qb_map_t *map, const char *key)¶
Gets the value corresponding to the given key. Return values:NULL (if the key does not exist)
a pointer to the value
qb_map_iter_t* qb_map_iter_create (qb_map_t *map)¶
Create an iterator.void qb_map_iter_free (qb_map_iter_t *i)¶
free the iterator Parameters:i the iterator
const char* qb_map_iter_next (qb_map_iter_t *i, void **value)¶
Get the next item. Parameters:i the iterator
value (out) the next item's value
Return values:
the next key
NULL - the end of the iteration
int32_t qb_map_notify_add (qb_map_t *m, const char *key, qb_map_notify_fnfn, int32_tevents, void *user_data)¶
Add a notifier to the map. Parameters:m the map instance
key the key (or prefix) to attach the notification to.
fn the callback
events the type of events to register for.
user_data a pointer to be passed into the callback
Note:
QB_MAP_NOTIFY_INSERTED is only valid on tries.
you can use key prefixes with trie maps.
Return values:
0 success
-errno failure
int32_t qb_map_notify_del (qb_map_t *m, const char *key, qb_map_notify_fnfn, int32_tevents)¶
Delete a notifier from the map. Note:the key,fn and events must match those you added.
Parameters:
m the map instance
key the key (or prefix) to attach the notification to.
fn the callback
events the type of events to register for.
Return values:
0 success
-errno failure
int32_t qb_map_notify_del_2 (qb_map_t *m, const char *key, qb_map_notify_fnfn, int32_tevents, void *user_data)¶
Delete a notifier from the map (including the userdata). Note:the key, fn, events and userdata must match those you
added.
Parameters:
m the map instance
key the key (or prefix) to attach the notification to.
fn the callback
events the type of events to register for.
user_data a pointer to be passed into the callback
Return values:
0 success
-errno failure
qb_map_iter_t* qb_map_pref_iter_create (qb_map_t *map, const char *prefix)¶
Create a prefix iterator. This will iterate over all items with the given prefix. Note:this is only supported by the trie.
void qb_map_put (qb_map_t *map, const char *key, const void *value)¶
Inserts a new key and value into a qb_map_t. If the key already exists in the qb_map_t, it gets replaced by the new key.int32_t qb_map_rm (qb_map_t *map, const char *key)¶
Removes a key/value pair from a map.qb_map_t* qb_skiplist_create (void)¶
Create a sorted map using a skiplist. Returns:the map instance
qb_map_t* qb_trie_create (void)¶
Create a sorted map using a Patricia trie or 'Radix tree'.void qb_trie_dump (qb_map_t *m)¶
print out the nodes in the trie (for debug purposes)Author¶
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