class Kramdown::Utils::LRUCache

A simple least recently used (LRU) cache.

The cache relies on the fact that Ruby's Hash class maintains insertion order. So deleting and re-inserting a key-value pair on access moves the key to the last position. When an entry is added and the cache is full, the first entry is removed.

Public Class Methods

new(size) click to toggle source

Creates a new LRUCache that can hold size entries.

# File lib/kramdown/utils/lru_cache.rb, line 20
def initialize(size)
  @size = size
  @cache = {}
end

Public Instance Methods

[](key) click to toggle source

Returns the stored value for key or nil if no value was stored under the key.

# File lib/kramdown/utils/lru_cache.rb, line 26
def [](key)
  (val = @cache.delete(key)).nil? ? nil : @cache[key] = val
end

[]=(key, value) click to toggle source

Stores the value under the key.

# File lib/kramdown/utils/lru_cache.rb, line 31
def []=(key, value)
  @cache.delete(key)
  @cache[key] = value
  @cache.shift if @cache.length > @size
end