This doesn't currently work because the OSC spec calls for the ints to be packed with a "twos complement" which basically means they are packed unsigned and converted when they get decoded.
[-1].pack('N').unpack('N') # => 16777216
[-1].pack('N').unpack('N').pack('V').unpack('l') # => -1
| #-- | |
| # This file is part of Sonic Pi: http://sonic-pi.net | |
| # Full project source: https://github.com/samaaron/sonic-pi | |
| # License: https://github.com/samaaron/sonic-pi/blob/master/LICENSE.md | |
| # | |
| # Copyright 2013, 2014, 2015 by Sam Aaron (http://sam.aaron.name). | |
| # All rights reserved. | |
| # | |
| # Permission is granted for use, copying, modification, and | |
| # distribution of modified versions of this work as long as this | |
| # notice is included. | |
| #++ | |
| require 'strscan' | |
| module SonicPi | |
| class OscDecode | |
| def initialize(use_cache = false, cache_size=1000) | |
| @float_cache = {} | |
| @integer_cache = {} | |
| @cache_size = cache_size | |
| @num_cached_integers = 0 | |
| @num_cached_floats = 0 | |
| @string_terminator = Regexp.new("\x00") | |
| @tag_separator = ',' | |
| @args = [] | |
| @i_tag = "i" | |
| @f_tag = "f" | |
| @s_tag = "s" | |
| @d_tag = "d" | |
| @h_tag = "h" | |
| @b_tag = "b" | |
| @cap_n = 'N' | |
| @cap_g = 'G' | |
| @low_g = 'g' | |
| @low_l = 'l' | |
| @q_lt = 'q>' | |
| @binary_encoding = "BINARY" | |
| end | |
| def decode_single_message(msg) | |
| ## Note everything is inlined here for effienciency to remove the | |
| ## cost of method dispatch. Apologies if this makes it harder to | |
| ## read & understand. See http://opensoundcontrol.org for spec. | |
| m = StringScanner.new(msg) | |
| pack_string = "" | |
| # Get OSC address e.g. /foo | |
| m.skip_until(@string_terminator) | |
| m.pos = 4 * ((m.pos + 0.01)/4).ceil | |
| pack_string << "Z#{m.pos}" | |
| # Let's see if we have some args.. | |
| # check the next char to see if it's a comma | |
| if m.peek(1) == @tag_separator | |
| # Get type tags | |
| orig_idx = m.pos | |
| tags = m.scan_until(@string_terminator) | |
| m.pos = 4 * ((m.pos + 0.01)/4).ceil | |
| if tags.length > 1 | |
| pack_string << "Z#{m.pos - orig_idx}" | |
| end | |
| # skip the comma | |
| tags.each_char do |t| | |
| case t | |
| when @tag_separator | |
| # skip the comma | |
| nil | |
| when @string_terminator | |
| # skip the null bytes | |
| nil | |
| when @i_tag | |
| # int32 | |
| m.pos = m.pos+4 | |
| pack_string << @cap_n | |
| when @f_tag | |
| # float32 | |
| m.pos = m.pos+4 | |
| pack_string << @low_g | |
| when @s_tag | |
| # string | |
| orig_idx = m.pos | |
| m.skip_until(@string_terminator) | |
| m.pos = 4 * ((m.pos + 0.01)/4).ceil | |
| pack_string << "Z#{m.pos - orig_idx}" | |
| when @d_tag | |
| # double64 | |
| m.pos = m.pos+8 | |
| pack_string << @cap_g | |
| when @h_tag | |
| # int64 | |
| m.pos = m.pos+8 | |
| pack_string << @q_lt | |
| when @b_tag | |
| # binary blob | |
| orig_idx = m.pos | |
| pack_string << @cap_n | |
| blob_length = m.getch.unpack(@cap_n)[0] | |
| m.skip(Regexp.new(".#{blob_length}")) | |
| pack_string << "Z#{m.pos - orig_idx}" | |
| m.pos = 4 * ((m.pos + 0.01)/4).ceil | |
| else | |
| raise "Unknown OSC type #{t}" | |
| end | |
| end | |
| end | |
| address, tags, *args = msg.unpack(pack_string) | |
| [address, args] | |
| end | |
| end | |
| end |
http://stackoverflow.com/questions/4886994/reading-a-binary-16-bit-signed-big-endian-integer-in-ruby
http://stackoverflow.com/questions/5236059/unpack-signed-little-endian-in-ruby
https://github.com/aberant/osc-ruby/blob/master/lib/osc-ruby/osc_packet.rb#L107
https://github.com/supercollider/supercollider/blob/25a296ff544f04850be2ce0f93282131d3c7d6d9/external_libraries/oscpack_1_1_0/osc/OscOutboundPacketStream.cpp#L60