RubyBits

RubyBits is a library that makes dealing with binary formats easier. In particular, it provides the Structure class, which allows for easy parsing and creation of binary strings according to specific formats. More usage information can be found in the docs or by looking at the specs.

You can install via rubygems with gem install rubybits.

Example:

class NECProjectorFormat < RubyBits::Structure
  unsigned :id1,     8,    "Identification data assigned to each command"
  unsigned :id2,     8,    "Identification data assigned to each command"
  unsigned :p_id,    8,    "Projector ID"
  unsigned :m_code,  4,    "Model code for projector"
  unsigned :len,     12,   "Length of data in bytes"
  variable :data,          "Packet data", :length => :len, :unit => :byte
  unsigned :checksum,8,    "Checksum"

  checksum :checksum do |bytes|
    bytes[0..-2].inject{|sum, byte| sum + byte} & 255
  end
end

NECProjectorFormat.parse(buffer)
  => [[<NECProjectorFormat>, <NECProjectorFormat>], rest]

NECProjectorFormat.new(:id1 => 0x44, :id2 => 2, :p_id => 0, :m_code => 0, :len => 5, :data => "hello").to_s.bytes.to_a
  => [0x44, 0x2, 0x05, 0x00, 0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x5F]