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