+(defun gnus-list-range-intersection (list ranges)
+ "Return a list of numbers in LIST that are members of RANGES.
+LIST is a sorted list."
+ (setq ranges (gnus-range-normalize ranges))
+ (let (number result)
+ (while (setq number (pop list))
+ (while (and ranges
+ (if (numberp (car ranges))
+ (< (car ranges) number)
+ (< (cdar ranges) number)))
+ (setq ranges (cdr ranges)))
+ (when (and ranges
+ (if (numberp (car ranges))
+ (= (car ranges) number)
+ ;; (caar ranges) <= number <= (cdar ranges)
+ (>= number (caar ranges))))
+ (push number result)))
+ (nreverse result)))
+
+(defalias 'gnus-inverse-list-range-intersection 'gnus-list-range-difference)
+
+(defun gnus-list-range-difference (list ranges)
+ "Return a list of numbers in LIST that are not members of RANGES.
+LIST is a sorted list."
+ (setq ranges (gnus-range-normalize ranges))
+ (let (number result)
+ (while (setq number (pop list))
+ (while (and ranges
+ (if (numberp (car ranges))
+ (< (car ranges) number)
+ (< (cdar ranges) number)))
+ (setq ranges (cdr ranges)))
+ (when (or (not ranges)
+ (if (numberp (car ranges))
+ (not (= (car ranges) number))
+ ;; not ((caar ranges) <= number <= (cdar ranges))
+ (< number (caar ranges))))
+ (push number result)))
+ (nreverse result)))
+