KMCache

Inspired by YYCache.

Usage

1. Clone or download the zip into your computer, copy the KMCache folder into your project

2. If you are using cocoapods:

   pod "KMCache"

Thought

Using CFMutableDictinaryRef as a container for quick searching. Create _cache_node and _cache_linked_list to build a linked list for building ordered data. _cache_node is a node with properties of key, value, timestamp, size, and pointers of _prev and _next.It store object and other infomations. _cache_linked_list is ordered by time of insertion, and refresh the node when the node use again.

Think it as a queue, every time you want to add an object into cache, first create a node, and append the node to the tail of the queue.It does two things when append a node: 1. Add the node into dictionary. 2. Set the node's prev pointer to the tail of the queue, and the node becomes new tail.

Searching is getting values from a dictionary.

KMCache provide two release types, release by time and by size. Node's infomation contains time property, it will check this when cache auto-clean it self.

KMCache will auto count the size of dictionary data's size before, but this really cost a lot to do so. Think about it, every time we append a node into the list, we must cast dictionay to NSData and count it. What was worse, if the size of dictionary is too large, we don't know how many nodes should we release. So I give it up.

Finally, with the help of YYCache and NSCache's comment, the better way is to set a property of _cache_node for recording the size of node. But the size is not automatically generated, it's set by user.

Atention

Auto-clean will run every 5 seconds(by default), I set a NSTimer in KMCache. The timer is add into the main runloop, so if the main thread is doing something synchronously, the timer will stop too.