bitmask.rb

flag_defs = [{
  :name => "member1",
  :position => 0,
  :value => true
},
{
  :name => "member2",
  :position => 1,
  :value => true
},
{
  :name => "member3",
  :position => 2,
  :value => true
}]

flags_state = 0

def value(flag, flags_state)
  flags_state & (1 << flag[:position]) > 0
end

def update_flag_state(flag_defs, flags_state)
  flag_defs.each do |f|
    if f[:value]
      puts " doing #{flags_state.to_s(2)} |= #{(1 << f[:position]).to_s(2)}    #{(flags_state | (1 << f[:position])).to_s(2)}"
      flags_state |= (1 << f[:position])
    else
      puts " doing #{flags_state.to_s(2)} &= #{(~(1 << f[:position])).to_s(2)}    #{(flags_state & ~(1 << f[:position])).to_s(2)}"
      flags_state &= ~(1 << f[:position])
    end
    #puts "  flags_state = #{flags_state.to_s(2)}"
  end
  flags_state
end

flags_state = update_flag_state(flag_defs, flags_state)
puts "flags_state=#{flags_state}"
flag_defs.each {|f| puts "#{f[:name]}=#{value(f, flags_state)}"}


fl=flag_defs.shuffle.first
fl[:value] = !fl[:value]

flags_state = update_flag_state(flag_defs, flags_state)
puts "flags_state=#{flags_state}"
flag_defs.each {|f| puts "#{f[:name]}=#{value(f, flags_state)}"}