statuses.rb

require "ffi"

module Scada
  module ResultSet
    class Statuses
      include Enumerable
      class Status < Struct.new(:id, :value, :condition, :error)
        def to_s
          if to_i == 0
            "open"
          else
            "closed"
          end
        end

        def to_i
          self.value.to_i
        end
      end

      attr_accessor :error_code, :ids, :values, :conditions, :errors, :size
      private :size=

      def initialize(ids, result_size)
        self.size = result_size
        self.error_code = FFI::MemoryPointer.new(:ulong)
        self.ids = ids
        self.values = FFI::MemoryPointer.new(:uchar, result_size)
        self.conditions = FFI::MemoryPointer.new(:uchar, result_size)
        self.errors = FFI::MemoryPointer.new(:ulong, result_size)
      end

      def each
        return enum(__callee__) unless block_given?
        ruby_ids.each_with_index do |id, index|
          yield Status.new(id, ruby_values[index], ruby_conditions[index], ruby_errors[index])
        end
      end

      def to_a
        [error_code, ids.ids, values, conditions, errors]
      end

      private
      def ruby_ids
        @ruby_ids ||= ids.ids.read_array_of_ulong(size)
      end

      def ruby_values
        @ruby_values ||= values.read_array_of_char(size)
      end

      def ruby_conditions
        @ruby_conditions ||= conditions.read_array_of_uchar(size)
      end

      def ruby_errors
        @ruby_errors ||= errors.read_array_of_ulong(size)
      end
    end
  end
end