class BinData::DelayedIO

a struct if multiple fields are required.
:type
The single type inside the delayed io. Use
:read_abs_offset

The abs_offset to start reading at.
an object. These params are:
Parameters may be provided at initialisation to control the behaviour of
== Parameters
s.to_binary_s #=> “hellox05”
s = ReversePascalString.read(“hellox05”)
end
uint8 :len, value: -> { str.length }
skip to_abs_offset: -> { total_size - 1 }
count_bytes_remaining :total_size
end
string read_length: :len
delayed_io :str, read_abs_offset: 0 do
auto_call_delayed_io
class ReversePascalString < BinData::Record
automatically perform the extra passes.
You can use the auto_call_delayed_io keyword to cause #read and #write to
obj.to_binary_s { obj.write_now! } #=> “x00x00x00x11x12”
obj.read(“x00x00x00x11x12”) { obj.read_now! } #=> 0x1122
- OR -
obj #=> 0x1112
obj.read_now!
obj #=> 0
obj.read(“x00x00x00x11x12”)
obj = BinData::DelayedIO.new(read_abs_offset: 3, type: :uint16be)
require ‘bindata’
must specify the abs_offset of the I/O operation.
#write_now! methods to process an additional pass. This additional pass
#read or #write calls. The user must explicitly call the #read_now! or
DelayedIO supports multi pass processing. It works by ignoring the normal
reason is seeking backwards in the input stream.
However, some binary formats require multi pass processing. A common
BinData declarations are evaluated in a single pass.

def abs_offset 

def abs_offset
  @abs_offset || eval_parameter(:read_abs_offset)
end

def abs_offset=(offset)

Sets the +abs_offset+ to use when writing this object. 
def abs_offset=(offset)
  @abs_offset = offset
end

def assign(val) 

def assign(val)
  @type.assign(val)
end

def clear? 

def clear?
  @type.clear?
end

def do_num_bytes #:nodoc:

:nodoc: 
def do_num_bytes #:nodoc:
  0
end

def do_read(io) #:nodoc:

:nodoc: 
def do_read(io) #:nodoc:
  @read_io = io
end

def do_write(io) #:nodoc:

:nodoc: 
def do_write(io) #:nodoc:
  @write_io = io
end

def initialize_instance 

def initialize_instance
  @type       = get_parameter(:type).instantiate(nil, self)
  @abs_offset = nil
  @read_io    = nil
  @write_io   = nil
end

def method_missing(symbol, *args, &block) #:nodoc:

:nodoc: 
def method_missing(symbol, *args, &block) #:nodoc:
  @type.__send__(symbol, *args, &block)
end

def num_bytes 

def num_bytes
  @type.num_bytes
end

def read_now!

The reading is delayed until this method is called.
DelayedIO objects aren't read when #read is called. 
def read_now!
  raise IOError, "read from where?" unless @read_io
  @read_io.seekbytes(abs_offset - @read_io.offset)
  start_read do
    @type.do_read(@read_io)
  end
end

def rel_offset 

def rel_offset
  abs_offset
end

def respond_to?(symbol, include_private = false) #:nodoc:

:nodoc: 
def respond_to?(symbol, include_private = false) #:nodoc:
  @type.respond_to?(symbol, include_private) || super
end

def snapshot 

def snapshot
  @type.snapshot
end

def write_now!

The writing is delayed until this method is called.
DelayedIO objects aren't written when #write is called. 
def write_now!
  raise IOError, "write to where?" unless @write_io
  @write_io.seekbytes(abs_offset - @write_io.offset)
  @type.do_write(@write_io)
end