module BinData::ByteAlignPlugin

Align fields to a multiple of :byte_align

Public Instance Methods

align_obj?(obj) click to toggle source
# File lib/bindata/struct.rb, line 331
def align_obj?(obj)
  obj.has_parameter?(:byte_align)
end
bytes_to_align(obj, rel_offset) click to toggle source
# File lib/bindata/struct.rb, line 326
def bytes_to_align(obj, rel_offset)
  align = obj.eval_parameter(:byte_align)
  (align - (rel_offset % align)) % align
end
do_read(io) click to toggle source
# File lib/bindata/struct.rb, line 283
def do_read(io)
  initial_offset = io.offset
  instantiate_all_objs
  @field_objs.each do |f|
    if include_obj?(f)
      if align_obj?(f)
        io.seekbytes(bytes_to_align(f, io.offset - initial_offset))
      end
      f.do_read(io)
    end
  end
end
do_write(io) click to toggle source
# File lib/bindata/struct.rb, line 296
def do_write(io)
  initial_offset = io.offset
  instantiate_all_objs
  @field_objs.each do |f|
    if include_obj?(f)
      if align_obj?(f)
        io.writebytes("\x00" * bytes_to_align(f, io.offset - initial_offset))
      end
      f.do_write(io)
    end
  end
end
sum_num_bytes_below_index(index) click to toggle source
# File lib/bindata/struct.rb, line 309
def sum_num_bytes_below_index(index)
  sum = 0
  (0...@field_objs.length).each do |i|
    obj = @field_objs[i]
    if include_obj?(obj)
      sum = sum.ceil + bytes_to_align(obj, sum.ceil) if align_obj?(obj)

      break if i >= index

      nbytes = obj.do_num_bytes
      sum = (nbytes.is_a?(Integer) ? sum.ceil : sum) + nbytes
    end
  end

  sum
end