aukan-bitmask

Agnostic Bitmask Attribute

Installation

gem install aukan-bitmask

Bitmask

Usage:

flags = Bitmask.new({
  :bit_ids => [:flag1, :flag2, :flag3],
  :value => 0
})

# Setting the value of a bit
flags.set :flag2, true

flags.get :flag1 # false
flags.get :flag2 # true
flags.get :flag3 # false

flags.value         # 2
flags.value.to_s(2) # "10"

Reseting the mask value:

flags.value = 5

flags.get :flag1 # true
flags.get :flag2 # false
flags.get :flag3 # true

Changing the bit ids:

flags.value = 5

flags.bit_ids = [:flag1, :flag3, :flag2]  # Switching flag2 for flag3

flags.get :flag1 # true
flags.get :flag2 # true
flags.get :flag3 # false

BitmaskAttribute

Uses Bitmask to decorate a class attribute. Can be used on ActiveRecord or any ORM.

Usage:

class Something
  attr_accessor :flags

  include BitmaskAttribute
  bitmask_attribute :flags, {
    :bit_ids => [
      :flag1, :flag2, :flag3
    ],
    :default_value => 3
  }
end

algo = Something.new
algo.flags_bitmask.set(:flag1, false)

algo.flags_bitmask.get(:flag1) # false
algo.flags_bitmask.get(:flag2) # true

To add accessor methods for each flag (flag1/flag1?/flag1=) pass the option :accessors => true.

ActiveRecord Integration

If ActiveRecord is loaded, the "dirty" methods are emulated for the bitmask object:

• flags_bitmask_changed?
• flags_bitmask_was

If :accessors is enabled, they are emulated for each attribute:

• flag1_changed?
• flag1_was

ActiveRecord typecasting is used when setting values: common strings found in web forms like "1"/"0" convert to true/false respectively.