+(defun gnus-remove-from-range (range1 range2)
+ "Return a range that has all articles from RANGE2 removed from RANGE1.
+The returned range is always a list. RANGE2 can also be a unsorted
+list of articles. RANGE1 is modified by side effects, RANGE2 is not
+modified."
+ (if (or (null range1) (null range2))
+ range1
+ (let (out r1 r2 r1_min r1_max r2_min r2_max
+ (range2 (gnus-copy-sequence range2)))
+ (setq range1 (if (listp (cdr range1)) range1 (list range1))
+ range2 (sort (if (listp (cdr range2)) range2 (list range2))
+ (lambda (e1 e2)
+ (< (if (consp e1) (car e1) e1)
+ (if (consp e2) (car e2) e2))))
+ r1 (car range1)
+ r2 (car range2)
+ r1_min (if (consp r1) (car r1) r1)
+ r1_max (if (consp r1) (cdr r1) r1)
+ r2_min (if (consp r2) (car r2) r2)
+ r2_max (if (consp r2) (cdr r2) r2))
+ (while (and range1 range2)
+ (cond ((< r2_max r1_min) ; r2 < r1
+ (pop range2)
+ (setq r2 (car range2)
+ r2_min (if (consp r2) (car r2) r2)
+ r2_max (if (consp r2) (cdr r2) r2)))
+ ((and (<= r2_min r1_min) (<= r1_max r2_max)) ; r2 overlap r1
+ (pop range1)
+ (setq r1 (car range1)
+ r1_min (if (consp r1) (car r1) r1)
+ r1_max (if (consp r1) (cdr r1) r1)))
+ ((and (<= r2_min r1_min) (<= r2_max r1_max)) ; r2 overlap min r1
+ (pop range2)
+ (setq r1_min (1+ r2_max)
+ r2 (car range2)
+ r2_min (if (consp r2) (car r2) r2)
+ r2_max (if (consp r2) (cdr r2) r2)))
+ ((and (<= r1_min r2_min) (<= r2_max r1_max)) ; r2 contained in r1
+ (if (eq r1_min (1- r2_min))
+ (push r1_min out)
+ (push (cons r1_min (1- r2_min)) out))
+ (pop range2)
+ (if (< r2_max r1_max) ; finished with r1?
+ (setq r1_min (1+ r2_max))
+ (pop range1)
+ (setq r1 (car range1)
+ r1_min (if (consp r1) (car r1) r1)
+ r1_max (if (consp r1) (cdr r1) r1)))
+ (setq r2 (car range2)
+ r2_min (if (consp r2) (car r2) r2)
+ r2_max (if (consp r2) (cdr r2) r2)))
+ ((and (<= r2_min r1_max) (<= r1_max r2_max)) ; r2 overlap max r1
+ (if (eq r1_min (1- r2_min))
+ (push r1_min out)
+ (push (cons r1_min (1- r2_min)) out))
+ (pop range1)
+ (setq r1 (car range1)
+ r1_min (if (consp r1) (car r1) r1)
+ r1_max (if (consp r1) (cdr r1) r1)))
+ ((< r1_max r2_min) ; r2 > r1
+ (pop range1)
+ (if (eq r1_min r1_max)
+ (push r1_min out)
+ (push (cons r1_min r1_max) out))
+ (setq r1 (car range1)
+ r1_min (if (consp r1) (car r1) r1)
+ r1_max (if (consp r1) (cdr r1) r1)))))
+ (when r1
+ (if (eq r1_min r1_max)
+ (push r1_min out)
+ (push (cons r1_min r1_max) out))
+ (pop range1))
+ (while range1
+ (push (pop range1) out))
+ (nreverse out))))