(use z3 posix)

;;; comparing performance of z3-compression, versus compression using
;;; an external gzip process. I know this is apples and oranges, but
;;; I'm just confused by the really poor performance of z3. Am I doing
;;; something wrong?

(define-macro (repeat-test n . body)
  (let ((loop (gensym "loop"))
        (times (gensym "times")))
    `(begin (printf "~%Test expression is: ~a~%" ',@body)
            (printf "Evaluating once. Return value is: ~s~%" ,@body)
            (printf "Repeating ~a times:~%" ,n)
            (time (let ,loop ((,times ,n))
                  (when (positive? ,times)
                    ,@body
                    (,loop (sub1 ,times))))))))

(define (gzip-string s)
  (receive (in out pid)
      (process "gzip")
    (write-string s #f out)
    (close-output-port out)
    (let ((result (read-string #f in)))
      (close-input-port in)
      result)))


(define (z3:compress-string input)
  (let* ((dest (open-output-string))
         (r (lambda (x) (display x dest)))
         (ze (z3:encode-init)))
    (let loop ((c input))
      (let ((t (z3:encode ze r c)))
        (when t
          (loop (substring c t)))))
    (get-output-string dest)))

(define *input* (make-string 1000 #\x))

(repeat-test 1000  (string-length (gzip-string *input*)))
(repeat-test 1000  (string-length (z3:compress-string *input*)))