class DBus::RawMessage

A message while it is being parsed: a binary string, with a position cursor (pos), and an endianness tag.

Attributes

endianness[R]

@return [:little,:big]

pos[R]

@return [Integer] position in the byte buffer

Public Class Methods

endianness(tag_char) click to toggle source

Get the endiannes switch as a Symbol, which will make using it slightly more efficient @param tag_char [String] @return [:little,:big]

   # File lib/dbus/raw_message.rb
37 def self.endianness(tag_char)
38   case tag_char
39   when LIL_END
40     :little
41   when BIG_END
42     :big
43   else
44     raise InvalidPacketException, "Incorrect endianness #{tag_char.inspect}"
45   end
46 end

new(bytes, endianness = nil) click to toggle source

@param bytes [String] @param endianness [:little,:big,nil]

if not given, read the 1st byte of *bytes*

   # File lib/dbus/raw_message.rb
27 def initialize(bytes, endianness = nil)
28   @bytes = bytes
29   @pos = 0
30   @endianness = endianness || self.class.endianness(@bytes[0])
31 end

Public Instance Methods

align(alignment) click to toggle source

Align the pos index on a multiple of alignment @param alignment [Integer] must be 1, 2, 4 or 8 @return [void]

   # File lib/dbus/raw_message.rb
75 def align(alignment)
76   case alignment
77   when 1
78     nil
79   when 2, 4, 8
80     bits = alignment - 1
81     pad_size = ((@pos + bits) & ~bits) - @pos
82     pad = read(pad_size)
83     unless pad.bytes.all?(&:zero?)
84       raise InvalidPacketException, "Alignment bytes are not NUL"
85     end
86   else
87     raise ArgumentError, "Unsupported alignment #{alignment}"
88   end
89 end

read(size) click to toggle source

@return [String] @raise IncompleteBufferException if there are not enough bytes remaining TODO: stress test this with encodings. always binary?

   # File lib/dbus/raw_message.rb
57 def read(size)
58   want!(size)
59   ret = @bytes.slice(@pos, size)
60   @pos += size
61   ret
62 end

remaining_bytes() click to toggle source

@return [String] @api private

   # File lib/dbus/raw_message.rb
66 def remaining_bytes
67   # This returns "" if pos is just past the end of the string,
68   # and nil if it is further.
69   @bytes[@pos..-1]
70 end

want!(size) click to toggle source

@return [void] @raise IncompleteBufferException if there are not enough bytes remaining

   # File lib/dbus/raw_message.rb
50 def want!(size)
51   raise IncompleteBufferException if @pos + size > @bytes.bytesize
52 end