-
-(defun unix-simplify-pathname (src)
- (declare (type simple-string src))
- (let* ((src-len (length src))
- (dst (make-string src-len :element-type 'character))
- (dst-len 0)
- (dots 0)
- (last-slash nil))
- (macrolet ((deposit (char)
- `(progn
- (setf (schar dst dst-len) ,char)
- (incf dst-len))))
- (dotimes (src-index src-len)
- (let ((char (schar src src-index)))
- (cond ((char= char #\.)
- (when dots
- (incf dots))
- (deposit char))
- ((char= char #\/)
- (case dots
- (0
- ;; either ``/...' or ``...//...'
- (unless last-slash
- (setf last-slash dst-len)
- (deposit char)))
- (1
- ;; either ``./...'' or ``..././...''
- (decf dst-len))
- (2
- ;; We've found ..
- (cond
- ((and last-slash (not (zerop last-slash)))
- ;; There is something before this ..
- (let ((prev-prev-slash
- (position #\/ dst :end last-slash :from-end t)))
- (cond ((and (= (+ (or prev-prev-slash 0) 2)
- last-slash)
- (char= (schar dst (- last-slash 2)) #\.)
- (char= (schar dst (1- last-slash)) #\.))
- ;; The something before this .. is another ..
- (deposit char)
- (setf last-slash dst-len))
- (t
- ;; The something is some directory or other.
- (setf dst-len
- (if prev-prev-slash
- (1+ prev-prev-slash)
- 0))
- (setf last-slash prev-prev-slash)))))
- (t
- ;; There is nothing before this .., so we need to keep it
- (setf last-slash dst-len)
- (deposit char))))
- (t
- ;; something other than a dot between slashes
- (setf last-slash dst-len)
- (deposit char)))
- (setf dots 0))
- (t
- (setf dots nil)
- (setf (schar dst dst-len) char)
- (incf dst-len))))))
- (when (and last-slash (not (zerop last-slash)))
- (case dots
- (1
- ;; We've got ``foobar/.''
- (decf dst-len))
- (2
- ;; We've got ``foobar/..''
- (unless (and (>= last-slash 2)
- (char= (schar dst (1- last-slash)) #\.)
- (char= (schar dst (- last-slash 2)) #\.)
- (or (= last-slash 2)
- (char= (schar dst (- last-slash 3)) #\/)))
- (let ((prev-prev-slash
- (position #\/ dst :end last-slash :from-end t)))
- (if prev-prev-slash
- (setf dst-len (1+ prev-prev-slash))
- (return-from unix-simplify-pathname
- (coerce "./" 'simple-string))))))))
- (cond ((zerop dst-len)
- "./")
- ((= dst-len src-len)
- dst)
- (t
- (subseq dst 0 dst-len)))))
-