Method: OpenC3::Structure#define

Defined in:

lib/openc3/packets/structure.rb

#define(item) ⇒ StrutureItem

Adds the given item to the items hash. It also resizes the buffer to accomodate the new item.

Parameters:

• item (StructureItem) —

  The structure item to add

Returns:

• (StrutureItem) —

  The struture item defined

# File 'lib/openc3/packets/structure.rb', line 217

def define(item)
  # Handle Overwriting Existing Item
  if @items[item.name]
    item_index = nil
    @sorted_items.each_with_index do |sorted_item, index|
      if sorted_item.name == item.name
        item_index = index
        break
      end
    end
    @sorted_items.delete_at(item_index) if item_index < @sorted_items.length
  end

  # Add to Sorted Items
  unless @sorted_items.empty?
    last_item = @sorted_items[-1]
    @sorted_items << item
    # If the current item or last item have a negative offset then we have
    # to re-sort. We also re-sort if the current item is less than the last
    # item because we are inserting.
    if last_item.bit_offset <= 0 or item.bit_offset <= 0 or item.bit_offset < last_item.bit_offset
      @sorted_items = @sorted_items.sort
    end
  else
    @sorted_items << item
  end

  # Add to the overall hash of defined items
  @items[item.name] = item
  # Update fixed size knowledge
  @fixed_size = false if (item.data_type != :DERIVED and item.bit_size <= 0) or (item.array_size and item.array_size <= 0)

  # Recalculate the overall defined length of the structure
  update_needed = false
  if item.bit_offset >= 0
    if item.bit_size > 0
      if item.array_size
        if item.array_size >= 0
          item_defined_length_bits = item.bit_offset + item.array_size
        else
          item_defined_length_bits = item.bit_offset
        end
      else
        item_defined_length_bits = item.bit_offset + item.bit_size
      end
      if item_defined_length_bits > @pos_bit_size
        @pos_bit_size = item_defined_length_bits
        update_needed = true
      end
    else
      if item.bit_offset > @pos_bit_size
        @pos_bit_size = item.bit_offset
        update_needed = true
      end
    end
  else
    if item.bit_offset.abs > @neg_bit_size
      @neg_bit_size = item.bit_offset.abs
      update_needed = true
    end
  end
  if update_needed
    @defined_length_bits = @pos_bit_size + @neg_bit_size
    @defined_length = @defined_length_bits / 8
    @defined_length += 1 if @defined_length_bits % 8 != 0
  end

  # Resize the buffer if necessary
  resize_buffer() if @buffer

  return item
end