Slow in ECL

(defparameter *what-we-already-have* (make-hash-table :test #'equal))

(defparameter *aggregate-storage-directory*
  (ensure-directories-exist
   (merge-pathnames
    (format nil "Desktop_pics/dpool/")
    (user-homedir-pathname))))

(defun sha1-file (path)
  (let ((sha1 (ironclad:make-digest 'ironclad:sha1)))
    (with-open-file (stream path :element-type '(unsigned-byte 8))
      (ironclad:update-digest sha1 stream)
      (values (ironclad:byte-array-to-hex-string (ironclad:produce-digest sha1)) path))))

(defun load-pool (&key (path *aggregate-storage-directory*))
  ;; for every file in the given directory (path), calculate its hash
  ;; and put it in the special table
  (loop for file in (uiop:directory-files path)
        for (hash path) = (multiple-value-list (sha1-file file))
        :do (progn
              (format t "~&~A :: ~A" hash path)
              (setf (gethash hash *what-we-already-have*) path)
              (format t "     [Done]"))))