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|
module Tins
class LRUCache
include Enumerable
class << self
private
my_nil = Object.new.freeze
define_method(:not_exist) do
my_nil
end
end
def initialize(capacity)
@capacity = capacity
@data = {}
end
attr_reader :capacity
def [](key)
case value = @data.delete(key){ not_exist }
when not_exist
nil
else
@data[key] = value
end
end
def []=(key, value)
@data.delete(key)
@data[key] = value
if @data.size > @capacity
@data.delete(@data.keys.first)
end
value
end
def each(&block)
@data.reverse_each(&block)
end
def delete(key)
@data.delete(key)
end
def clear
@data.clear
end
def size
@data.size
end
private
def not_exist
self.class.send(:not_exist)
end
end
end
|
