This is a lisp implementation of the Open Sound Control protocol (or more accurately “data transport specification” or “encoding”). The code should be close to ANSI standard common lisp and provides self contained code for encoding and decoding of OSC data, messages, and bundles. Since OSC describes a transport independent encoding (and does not specify a transport layer) messages can be send using TCP, UDP or other network protocols (e.g. RFC 2549). It seems UDP is more common amongst programmes that communicate using OSC and. the osc-examples.lisp file contains a few simple examples of how to send and receive OSC via UDP. The examples are reasonably compatible with the packets send from/to max-msp, pd, supercollider and liblo. more details about OSC can be found at https://OpenSoundControl.org

The current version of this code is available from github

git clone https://github.com/zzkt/osc

or via quicklisp.. .

(ql:quickload "osc")

OSC 1.0 and 1.1 support

This implementation supports the OpenSoundControl Specification 1.0 and the required typetags listed in the OpenSoundControl Specification 1.1 (as described in an NIME 2009 paper ). Some optional types are supported.

Type tag	type	description	v1.0	v1.1	cl-osc
i	int32	32-bit big-endian two’s complement integer	R	R	YES
f	float32	32-bit big-endian IEEE 754 floating point number	R	R	YES
s	OSC-string	A sequence of non-null ASCII characters followed by a null,		R
		followed by 0-3 additional null characters. Total bits is a multiple of 32.	R	N	YES
b	OSC-blob	An int32 size count, followed by that many 8-bit bytes of arbitrary binary data,		R
		followed by 0-3 additional zero bytes. Total bits is a multiple of 32.	R	N	YES
T	True	No bytes are allocated in the argument data.	O	R
F	False	No bytes are allocated in the argument data.	O	R
N	Null	(aka nil, None, etc). No bytes are allocated in the argument data.	O	R
I	Impulse	(aka “bang”), used for event triggers. No bytes are allocated in the argument data.	O	R
t	OSC-timetag	an OSC timetag in NTP format, encoded in the data section	O	R
h	int64	64 bit big-endian two’s complement integer	O	O	YES
d	float64	64 bit (“double”) IEEE 754 floating point number	O	O
S	OSC-string	Alternate type represented as an OSC-string (e.g to differentiate “symbols” from “strings”)	O	O	YES
c		an ascii character, sent as 32 bits	O	O
r		32 bit RGBA color	O	O
m		4 byte MIDI message. Bytes from MSB to LSB are: port id, status byte, data1, data2	O	O
[		Indicates the beginning of an array. The tags following are for data in the Array.	O	O	YES?
]		Indicates the end of an array.	O	O	YES?

• *R*equired, *O*ptional and *N*ot supported (or *N*ot required).
• data is encoded as (vector (unsigned 8)) by cl-osc

Float encoding & decoding

(defun encode-float32 (f)
  "Encode an ieee754 float as a 4 byte vector. currently sbcl/cmucl specific."
  (encode-int32 (ieee-floats:encode-float32 f)))
  ;; #+sbcl (encode-int32 (sb-kernel:single-float-bits f))
  ;; #+cmucl (encode-int32 (kernel:single-float-bits f))
  ;; #+openmcl (encode-int32 (CCL::SINGLE-FLOAT-BITS f))
  ;; #+allegro (encode-int32 (multiple-value-bind (x y)
  ;;                           (excl:single-float-to-shorts f)
  ;;                           (+ (ash x 16) y)))
  ;; #-(or sbcl cmucl openmcl allegro ieee-floats) (error "Can't encode single-floats using this implementation."))

(defun decode-float32 (v)
  "Convert a vector of 4 bytes in network byte order into an ieee754 float."
  (ieee-floats:decode-float32 (decode-int32 v)))
  ;; #+sbcl (sb-kernel:make-single-float (decode-int32 v))
  ;; #+cmucl (kernel:make-single-float (decode-int32 v))
  ;; #+openmcl (CCL::HOST-SINGLE-FLOAT-FROM-UNSIGNED-BYTE-32 (decode-uint32 v))
  ;; #+allegro (excl:shorts-to-single-float (ldb (byte 16 16) (decode-int32 v))
  ;;                                        (ldb (byte 16 0) (decode-int32 v)))
  ;; #-(or sbcl cmucl openmcl allegro) (error "Can't decode single-floats using this implementation."))

(defun encode-float64 (d)
  "Encode an ieee754 float as a 8 byte vector. currently sbcl/cmucl specific."
  #+sbcl (cat (encode-int32 (sb-kernel:double-float-high-bits d))
              (encode-int32 (sb-kernel:double-float-low-bits d)))
  #-(or sbcl ieee-floats) (error "Can't encode double-floats using this implementation."))

(defun decode-float64 (v)
  "Convert a vector of 8 bytes in network byte order into an ieee754 float."
  #+sbcl (sb-kernel:make-double-float
          (decode-uint32 (subseq v 0 4))
          (decode-uint32 (subseq v 4 8)))
  #-(or sbcl ieee-floats) (error "Can't decode single-floats using this implementation."))