lru_eviction_queue

  • LRUEvictionQueue

    Declaration

    struct LRUEvictionQueue(KEY, VALUE);

    A LRU Eviction Queue for the D programming language

    Discussion

    Home page: https://github.com/workhorsy/lru_eviction_queue

    Version

    1.7.0

    License

    Boost Software License - Version 1.0

    Examples

    1. import lru_eviction_queue; import std.stdio : stdout; // Create a queue that will hold 3 items auto cache = LRUEvictionQueue!(string, int)(3); // Fire this event when an item is evicted cache.on_evict_cb = delegate(string key, ref int value) { stdout.writefln("Evicted item: %s", key); }; // Fire this event when an item is updated cache.on_update_cb = delegate(string key, ref int value) { stdout.writefln("Updated item: %s", key); }; // Add cache["aaa"] = 65; cache["bbb"] = 97; cache["ccc"] = 15; cache["ddd"] = 46; // Check that the key "aaa" was removed if (! cache.hasKey("aaa")) { stdout.writefln("Item \"aaa\" was evicted!"); } // Check that the key "ccc" was found if ("ccc" in cache) { stdout.writefln("Item \"ccc\" was found!"); } // Prints all the items in the cache foreach (key, ref value ; cache) { stdout.writefln("%s : %s", key, value); }

    • this

      Declaration

      this(size_t max_length);

      Creates a LRUEvictionQueue

      Parameters

      size_t max_length

      The max size of the queue. After this many items are added, the oldest items will be removed.

      Throws

      If max_length is less than 1, it will throw an Exception.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100);

    • hasKey

      Declaration

      bool hasKey(KEY key);

      Returns true if a key is still on the queue

      Parameters

      KEY key

      The name of the key to check.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); bool retval = cache.hasKey("name");

    • set

      Declaration

      void set(KEY key, VALUE value);

      Sets the value in the queue. Will fire the on_evict_cb event if it is a new item that pushes an item off the queue. Will fire the on_update_cb event if updating an already existing key.

      Parameters

      KEY key

      The key to set.

      VALUE value

      The value to set.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache.set("name", "Bob");

    • get

      Declaration

      VALUE get(KEY key, VALUE default_value);

      Gets the value in the queue

      Parameters

      KEY key

      The key to get.

      VALUE default_value

      The value returned if the key is not found.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); string name = cache.get("name", string.init);

    • remove

      Declaration

      void remove(KEY key);

      Removes the key from the queue. Does nothing if the key is not in the queue. Will not fire any events.

      Parameters

      KEY key

      The key to remove.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache["name"] = "Alice"; cache.remove("name");

    • clear

      Declaration

      void clear();

      Removes all the items from the queue. Will not fire any events.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache["name"] = "Tim"; cache.clear();

    • length

      Declaration

      size_t length();

      Returns the length of the queue.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache["name"] = "Alice"; size_t len = cache.length;

    • max_length

      Declaration

      size_t max_length();

      Returns the max length of the queue before items are removed.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); size_t max_len = cache.max_length;

    • keys

      Declaration

      KEY[] keys();

      Returns all the keys in the queue.

      Examples

      1. auto cache = LRUEvictionQueue!(string, int)(100); cache["bbb"] = 5; cache["zzz"] = 7; string[] keys = cache.keys();

    • opApply

      Declaration

      int opApply(scope int delegate(ref KEY key, ref VALUE value) dg);

      Used to iterate over the queue.

      Examples

      1. auto cache = LRUEvictionQueue!(string, int)(100); cache["bbb"] = 5; cache["zzz"] = 7; foreach (key, ref value ; cache) { }

    • opIndex

      Declaration

      VALUE opIndex(KEY key);

      Gets the value in the queue. Throws if the key is not found.

      Parameters

      KEY key

      The key to get.

      Throws

      If the key is not found, it will throw an Exception.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache["name"] = "Frank"; string name = cache["name"];

    • opIndexAssign

      Declaration

      VALUE opIndexAssign(VALUE value, KEY key);

      Sets the value in the queue. Will fire the on_evict_cb event if it is a new item that pushes an item off the queue. Will fire the on_update_cb event if updating an already existing key.

      Parameters

      KEY key

      The key to set.

      VALUE value

      The value to set.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache["name"] = "Lisa";

    • opBinary

      Declaration

      VALUE* opBinary(string op)(KEY rhs);

      Returns a pointer to the value in the queue, or null.

      Parameters

      KEY rhs

      The name of the key to check.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache["name"] = "Lisa"; string* result = "name" in cache;

    • on_evict_cb

      Declaration

      void delegate(KEY key, ref VALUE value) on_evict_cb;

      The event to fire when an existing key is evicted

      Parameters

      on_evict_cb

      The callback to fire.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(2); cache.on_evict_cb = delegate(string key, ref string value) { }; cache["aaa"] = "Lisa"; cache["bbb"] = "Sally"; cache["ccc"] = "Kevin";

    • on_update_cb

      Declaration

      void delegate(KEY key, ref VALUE value) on_update_cb;

      The event to fire when an existing key is updated

      Parameters

      on_update_cb

      The callback to fire.

      Examples

      1. auto cache = LRUEvictionQueue!(string, string)(100); cache.on_update_cb = delegate(string key, ref string value) { }; cache["name"] = "Lisa"; cache["name"] = "Sally";