On Mon, Jun 02, 2008 at 08:45:37AM -0700, elliott wrote: >Hi, > >I've reached a point in writing some code where I must read a singed >32bit integer from a socket. I've been using >NET.SOCKETS:RECEIVE-FROM to read '(unsigned-byte 8) values. Can >anyone suggest a good library (or alternate method) to help with the >conversion?
I'm afraid that you'll have to do manual conversion for the moment until
I'll add the proper routines to write into arrays other than
'(unsigned-byte 8). Here's a piece of code that can do just that,
albeit slowly.
(defun aref-32 (ub8-array &optional (offset 0) (endianess :little-endian) (type
:signed))
(let ((value
(ecase endianess
(:big-endian
(+ (ash (aref ub8-array offset) 24)
(ash (aref ub8-array (+ 1 offset)) 16)
(ash (aref ub8-array (+ 2 offset)) 8)
(aref ub8-array (+ 3 offset))))
(:little-endian
(+ (aref ub8-array offset)
(ash (aref ub8-array (+ 1 offset)) 8)
(ash (aref ub8-array (+ 2 offset)) 16)
(ash (aref ub8-array (+ 3 offset)) 24))))))
(if (and (eq :signed type) (logbitp 31 value))
(lognot (logxor value #xFFFFFFFF))
value)))
HU> (aref-32 #(255 0 0 0) 0 :big-endian :unsigned)
4278190080
HU> (aref-32 #(255 0 0 0) 0 :little-endian :unsigned)
255
HU> (aref-32 #(255 0 0 0) 0 :big-endian :signed)
-16777216
HU> (aref-32 #(255 0 0 0) 0 :little-endian :signed)
255
--
Stelian Ionescu a.k.a. fe[nl]ix
Quidquid latine dictum sit, altum videtur.
pgpP71SLX3wvl.pgp
Description: PGP signature
_______________________________________________ iolib-devel mailing list [email protected] http://common-lisp.net/cgi-bin/mailman/listinfo/iolib-devel
