new_contents: from mrcrowbar import models as mrc
  
  class MacBinary( mrc.Block ):
      version_old =   mrc.Const( mrc.UInt8( 0x00 ), 0 )
      name_size =     mrc.UInt8( 0x01, range=range( 1, 64 ) )
      name =          mrc.Bytes( 0x02, length=mrc.Ref( 'name_size' ) )
      type =          mrc.Bytes( 0x41, length=4 )
      creator =       mrc.Bytes( 0x45, length=4 )
      locked =        mrc.Bits( 0x49, 0b10000000 )
      invisible =     mrc.Bits( 0x49, 0b01000000 )
      bundle =        mrc.Bits( 0x49, 0b00100000 )
      system =        mrc.Bits( 0x49, 0b00010000 )
      bozo =          mrc.Bits( 0x49, 0b00001000 )
      busy =          mrc.Bits( 0x49, 0b00000100 )
      changed =       mrc.Bits( 0x49, 0b00000010 )
      inited =        mrc.Bits( 0x49, 0b00000001 )
      const1 =        mrc.Const( mrc.UInt8( 0x4a ), 0 )
      pos_y =         mrc.UInt16_BE( 0x4b )
      pos_x =         mrc.UInt16_BE( 0x4d )
      folder_id =     mrc.UInt16_BE( 0x4f )
      protected =     mrc.Bits( 0x51, 0b00000001 )
      const2 =        mrc.Const( mrc.UInt8( 0x52 ), 0 )
      data_size =     mrc.UInt32_BE( 0x53 )
      resource_size = mrc.UInt32_BE( 0x57 )
      created =       mrc.UInt32_BE( 0x5a )
      modified =      mrc.UInt32_BE( 0x5e )
  
  
      data =          mrc.Bytes( 0x80, length=mrc.Ref( 'data_size' ) )
      resource =      mrc.Bytes( mrc.EndOffset( 'data', align=0x80 ), length=mrc.Ref( 'resource_size' ) )
  
  
  
subject: add MacBinary