/prog/ - post you are run length encoding in lisp

Name: Anonymous 2014-10-05 3:18

critique mine pl0x:

(defun rle (str) ;run length encoding
  (let ((i 0) c count out)
    (while (< i (length str))
      (if (eq c (elt str i))
	  (setq count (1+ count))
	(when c
	  (setq out (append out (list (cons c count)))))
	(setq c (elt str i))
	(setq count 1))
      (setq i (1+ i)))
    (when c (setq out (append out (list (cons c count)))))
    out))

Name: Anonymous 2014-10-05 7:27

Yeah. I remember implementing it to read old graphic formats. Although LZ is a lot better
https://github.com/saniv/gfx/blob/master/pcx.lisp

(defun pcx-rle-line (o s e)
  (while (< (cdr s) e)
    (let ((v (% s))
          (c 1))
      (while (and (< (cdr s) e) (= (% 0 s) v) (< c 63))
        (% s)
        (incf c))
      (unless (and (= c 1) (/= (logand #xC0 v) #xC0))
        (ser o (Count 1 (logior #xC0 c))))
      (ser o (Value 1 v)))))

(defun pcx-derle-line (o s e)
  (while (< (cdr o) e)
    (let ((c (% s)))
      (if (/= (logand c #xC0) #xC0)
          (% o c)
          (let ((c (logxor c #xC0))
                (v (% s)))
            (while (plusp c)
              (% o v)
              (decf c)))))))

post you are run length encoding in lisp

1 Name: Anonymous 2014-10-05 3:18

2 Name: Anonymous 2014-10-05 7:27

Name: Anonymous 2014-10-05 3:18

Name: Anonymous 2014-10-05 7:27