Thu Jul 9 13:41:37 2009

Asterisk developer's documentation

ao2_container Struct Reference


Data Fields
bucket	buckets [0]
ao2_callback_fn *	cmp_fn
int	elements
ao2_hash_fn *	hash_fn
int	n_buckets
int	version

Detailed Description

A container; stores the hash and callback functions, information on the size, the hash bucket heads, and a version number, starting at 0 (for a newly created, empty container) and incremented every time an object is inserted or deleted. The assumption is that an object is never moved in a container, but removed and readded with the new number. The version number is especially useful when implementing iterators. In fact, we can associate a unique, monotonically increasing number to each object, which means that, within an iterator, we can store the version number of the current object, and easily look for the next one, which is the next one in the list with a higher number. Since all objects have a version >0, we can use 0 as a marker for 'we need the first object in the bucket'.

Todo:: Linking and unlink objects is typically expensive, as it involves a malloc() of a small object which is very inefficient. To optimize this, we allocate larger arrays of bucket_list's when we run out of them, and then manage our own freelist. This will be more efficient as we can do the freelist management while we hold the lock (that we need anyways).

Definition at line 305 of file astobj2.c.