sharplispers / chipz Goto Github PK

I'm not sure what the protocol is for something like this, could someone place this into ultralisp?

If it is something I can do via a mirroring fork, then I'll do it. If a sharplisper member is empowered to do so then I request that it be so.

And if there is good reason to avoid it, I'm all ears.

cheers

Hello,

i tried the following code with an error :

From linux shell :

:~> echo "huge" | bzip2 - > huge.bz2
:~> file huge.bz2
huge.bz2: bzip2 compressed data, block size = 900k

Lisp Code (according to the doc) :

(with-open-file (stream "huge.bz2"  :element-type '(unsigned-byte 8))
           (chipz:decompress nil 'chipz:bzip2 stream))

Error (SIMPLE-ERROR) during printing: #<CHIPZ:INVALID-BZIP2-DATA {1006A7BB43}>

With a little help from comp.lang.lisp, i think there is an error in the bzip2.lisp file.
In the following function :

(bzip2-selector1 (state)
               (declare (type bzip2-state state))
               (let ((n-groups (ensure-and-read-bits 3 state)))
                 (unless (<= 3 n-groups 6)
                   (error 'invalid-bzip2-data))
                 (setf (bzip2-state-n-groups state) n-groups)
(transition-to bzip2-selector2)))

the n-groups value is tested between 3 and 6.
But in the C code version (decompress.c v1.0.6) the test is between 2 and 6.
if (nGroups < 2 || nGroups > 6) RETURN(BZ_DATA_ERROR); (line 288)

With 2 instead of 3, no more error in the test.

Thanks

Following has a reasonable chance (30%+) of triggering EOF error from chipz:

(ql:quickload '(chipz salza2))

(let* ((d (map-into (make-array (expt 2 8) :element-type '(unsigned-byte 8))
                    (lambda () (random 255))))
       (v (salza2:compress-data d 'salza2:deflate-compressor)))
  (with-simple-restart (continue "continue")
    (let ((x (time (chipz:decompress nil 'chipz:deflate v))))
      (assert (equalp d x)))))

Not completely sure it is chipz rather than salza2, but other decompressors don't seem to object to the same data.