ruby/red-arrow-format/lib/arrow-format/bitmap.rb

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module ArrowFormat
  class Bitmap
    include Enumerable

    def initialize(buffer, n_values)
      @buffer = buffer
      @n_values = n_values
    end

    def [](i)
      (@validity_buffer.get_value(:U8, i / 8) & (1 << (i % 8))) > 0
    end

    def each
      return to_enum(__method__) unless block_given?

      n_bytes = @n_values / 8
      @buffer.each(:U8, 0, n_bytes) do |offset, value|
        7.times do |i|
          yield(value & (1 << (i % 8)))
        end
      end
      remained_bits = @n_values % 8
      unless remained_bits.zero?
        value = @buffer.get_value(:U8, n_bytes)
        remained_bits.times do |i|
          yield(value & (1 << (i % 8)))
        end
      end
    end
  end
end