MessagePack (msgpack) serialization format: Ruby parsing library

MessagePack (msgpack) is a system to serialize arbitrary structured data into a compact binary stream.

KS implementation details

License: CC0-1.0

References

This page hosts a formal specification of MessagePack (msgpack) serialization format using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.

The Ruby runtime library can be installed from RubyGems:

gem install kaitai-struct

Code

Parse a local file and get structure in memory:

data = Msgpack.from_file("path/to/local/file.MessagePack (msgpack) serialization format")

Or parse structure from a string of bytes:

bytes = "\x00\x01\x02..."
data = Msgpack.new(Kaitai::Struct::Stream.new(bytes))

After that, one can get various attributes from the structure by invoking getter methods like:

data.b1 # => First byte is msgpack message is either a piece of data by
itself or determines types of further, more complex data
structures.

Ruby source code to parse MessagePack (msgpack) serialization format

msgpack.rb

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

require 'kaitai/struct/struct'

unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
  raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end


##
# MessagePack (msgpack) is a system to serialize arbitrary structured
# data into a compact binary stream.
# @see https://github.com/msgpack/msgpack/blob/master/spec.md Source
class Msgpack < Kaitai::Struct::Struct
  def initialize(_io, _parent = nil, _root = self)
    super(_io, _parent, _root)
    _read
  end

  def _read
    @b1 = @_io.read_u1
    case b1
    when 211
      @int_extra = @_io.read_s8be
    when 209
      @int_extra = @_io.read_s2be
    when 210
      @int_extra = @_io.read_s4be
    when 208
      @int_extra = @_io.read_s1
    when 205
      @int_extra = @_io.read_u2be
    when 207
      @int_extra = @_io.read_u8be
    when 204
      @int_extra = @_io.read_u1
    when 206
      @int_extra = @_io.read_u4be
    end
    if is_float_32
      @float_32_value = @_io.read_f4be
    end
    if is_float_64
      @float_64_value = @_io.read_f8be
    end
    if is_str_8
      @str_len_8 = @_io.read_u1
    end
    if is_str_16
      @str_len_16 = @_io.read_u2be
    end
    if is_str_32
      @str_len_32 = @_io.read_u4be
    end
    if is_str
      @str_value = (@_io.read_bytes(str_len)).force_encoding("UTF-8")
    end
    if is_array_16
      @num_array_elements_16 = @_io.read_u2be
    end
    if is_array_32
      @num_array_elements_32 = @_io.read_u4be
    end
    if is_array
      @array_elements = Array.new(num_array_elements)
      (num_array_elements).times { |i|
        @array_elements[i] = Msgpack.new(@_io)
      }
    end
    if is_map_16
      @num_map_elements_16 = @_io.read_u2be
    end
    if is_map_32
      @num_map_elements_32 = @_io.read_u4be
    end
    if is_map
      @map_elements = Array.new(num_map_elements)
      (num_map_elements).times { |i|
        @map_elements[i] = MapTuple.new(@_io, self, @_root)
      }
    end
    self
  end
  class MapTuple < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @key = Msgpack.new(@_io)
      @value = Msgpack.new(@_io)
      self
    end
    attr_reader :key
    attr_reader :value
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-array Source
  def is_array_32
    return @is_array_32 unless @is_array_32.nil?
    @is_array_32 = b1 == 221
    @is_array_32
  end
  def int_value
    return @int_value unless @int_value.nil?
    if is_int
      @int_value = (is_pos_int7 ? pos_int7_value : (is_neg_int5 ? neg_int5_value : 4919))
    end
    @int_value
  end
  def str_len
    return @str_len unless @str_len.nil?
    if is_str
      @str_len = (is_fix_str ? (b1 & 31) : (is_str_8 ? str_len_8 : (is_str_16 ? str_len_16 : str_len_32)))
    end
    @str_len
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-array Source
  def is_fix_array
    return @is_fix_array unless @is_fix_array.nil?
    @is_fix_array = (b1 & 240) == 144
    @is_fix_array
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-map Source
  def is_map
    return @is_map unless @is_map.nil?
    @is_map =  ((is_fix_map) || (is_map_16) || (is_map_32)) 
    @is_map
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-array Source
  def is_array
    return @is_array unless @is_array.nil?
    @is_array =  ((is_fix_array) || (is_array_16) || (is_array_32)) 
    @is_array
  end
  def is_float
    return @is_float unless @is_float.nil?
    @is_float =  ((is_float_32) || (is_float_64)) 
    @is_float
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-str Source
  def is_str_8
    return @is_str_8 unless @is_str_8.nil?
    @is_str_8 = b1 == 217
    @is_str_8
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-map Source
  def is_fix_map
    return @is_fix_map unless @is_fix_map.nil?
    @is_fix_map = (b1 & 240) == 128
    @is_fix_map
  end
  def is_int
    return @is_int unless @is_int.nil?
    @is_int =  ((is_pos_int7) || (is_neg_int5)) 
    @is_int
  end
  def is_bool
    return @is_bool unless @is_bool.nil?
    @is_bool =  ((b1 == 194) || (b1 == 195)) 
    @is_bool
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-str Source
  def is_str_16
    return @is_str_16 unless @is_str_16.nil?
    @is_str_16 = b1 == 218
    @is_str_16
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-float Source
  def is_float_64
    return @is_float_64 unless @is_float_64.nil?
    @is_float_64 = b1 == 203
    @is_float_64
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-map Source
  def is_map_16
    return @is_map_16 unless @is_map_16.nil?
    @is_map_16 = b1 == 222
    @is_map_16
  end
  def is_neg_int5
    return @is_neg_int5 unless @is_neg_int5.nil?
    @is_neg_int5 = (b1 & 224) == 224
    @is_neg_int5
  end
  def pos_int7_value
    return @pos_int7_value unless @pos_int7_value.nil?
    if is_pos_int7
      @pos_int7_value = b1
    end
    @pos_int7_value
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-nil Source
  def is_nil
    return @is_nil unless @is_nil.nil?
    @is_nil = b1 == 192
    @is_nil
  end
  def float_value
    return @float_value unless @float_value.nil?
    if is_float
      @float_value = (is_float_32 ? float_32_value : float_64_value)
    end
    @float_value
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-array Source
  def num_array_elements
    return @num_array_elements unless @num_array_elements.nil?
    if is_array
      @num_array_elements = (is_fix_array ? (b1 & 15) : (is_array_16 ? num_array_elements_16 : num_array_elements_32))
    end
    @num_array_elements
  end
  def neg_int5_value
    return @neg_int5_value unless @neg_int5_value.nil?
    if is_neg_int5
      @neg_int5_value = -((b1 & 31))
    end
    @neg_int5_value
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-bool Source
  def bool_value
    return @bool_value unless @bool_value.nil?
    if is_bool
      @bool_value = b1 == 195
    end
    @bool_value
  end
  def is_pos_int7
    return @is_pos_int7 unless @is_pos_int7.nil?
    @is_pos_int7 = (b1 & 128) == 0
    @is_pos_int7
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-array Source
  def is_array_16
    return @is_array_16 unless @is_array_16.nil?
    @is_array_16 = b1 == 220
    @is_array_16
  end
  def is_str
    return @is_str unless @is_str.nil?
    @is_str =  ((is_fix_str) || (is_str_8) || (is_str_16) || (is_str_32)) 
    @is_str
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-str Source
  def is_fix_str
    return @is_fix_str unless @is_fix_str.nil?
    @is_fix_str = (b1 & 224) == 160
    @is_fix_str
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-str Source
  def is_str_32
    return @is_str_32 unless @is_str_32.nil?
    @is_str_32 = b1 == 219
    @is_str_32
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-map Source
  def num_map_elements
    return @num_map_elements unless @num_map_elements.nil?
    if is_map
      @num_map_elements = (is_fix_map ? (b1 & 15) : (is_map_16 ? num_map_elements_16 : num_map_elements_32))
    end
    @num_map_elements
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-float Source
  def is_float_32
    return @is_float_32 unless @is_float_32.nil?
    @is_float_32 = b1 == 202
    @is_float_32
  end

  ##
  # @see https://github.com/msgpack/msgpack/blob/master/spec.md#formats-map Source
  def is_map_32
    return @is_map_32 unless @is_map_32.nil?
    @is_map_32 = b1 == 223
    @is_map_32
  end

  ##
  # First byte is msgpack message is either a piece of data by
  # itself or determines types of further, more complex data
  # structures.
  attr_reader :b1
  attr_reader :int_extra
  attr_reader :float_32_value
  attr_reader :float_64_value
  attr_reader :str_len_8
  attr_reader :str_len_16
  attr_reader :str_len_32
  attr_reader :str_value
  attr_reader :num_array_elements_16
  attr_reader :num_array_elements_32
  attr_reader :array_elements
  attr_reader :num_map_elements_16
  attr_reader :num_map_elements_32
  attr_reader :map_elements
end