X-Git-Url: http://cgit.sxemacs.org/?a=blobdiff_plain;f=lisp%2Fgnus-range.el;h=2e0a9880a0adb717c760400f0794a685d9f72b44;hb=d39fd8da49167d94c91c07df12f645762a24fdae;hp=14cc4166442164ecf537747faf6da89975566157;hpb=ea459fd72ec9b5035d85cf5fbbd107945dfd9594;p=gnus

diff --git a/lisp/gnus-range.el b/lisp/gnus-range.el
index 14cc41664..2e0a9880a 100644
--- a/lisp/gnus-range.el
+++ b/lisp/gnus-range.el
@@ -61,6 +61,48 @@ If RANGE is a single range, return (RANGE). Otherwise, return RANGE."
       (setq list2 (cdr list2)))
     list1))
 
+(defun gnus-range-difference (range1 range2)
+  "Return the range of elements in RANGE1 that do not appear in RANGE2.
+Both ranges must be in ascending order."
+  (setq range1 (gnus-range-normalize range1))
+  (setq range2 (gnus-range-normalize range2))
+  (let* ((new-range (cons nil (copy-sequence range1)))
+         (r new-range)
+         (safe t))
+    (while (cdr r)
+      (let* ((r1 (cadr r))
+             (r2 (car range2))
+             (min1 (if (numberp r1) r1 (car r1)))
+             (max1 (if (numberp r1) r1 (cdr r1)))
+             (min2 (if (numberp r2) r2 (car r2)))
+             (max2 (if (numberp r2) r2 (cdr r2))))
+
+        (cond ((> min1 max1)
+               ;; Invalid range: may result from overlap condition (below)
+               ;; remove Invalid range
+               (setcdr r (cddr r)))
+              ((and (= min1 max1)
+                    (listp r1))
+               ;; Inefficient representation: may result from overlap condition (below)
+               (setcar (cdr r) min1))
+              ((not min2)
+               ;; All done with range2
+               (setq r nil))
+              ((< max1 min2)
+               ;; No overlap: range1 preceeds range2
+               (pop r))
+              ((< max2 min1)
+               ;; No overlap: range2 preceeds range1
+               (pop range2))
+              ((and (<= min2 min1) (<= max1 max2))
+               ;; Complete overlap: range1 removed
+               (setcdr r (cddr r)))
+              (t
+               (setcdr r (nconc (list (cons min1 (1- min2)) (cons (1+ max2) max1)) (cddr r)))))))
+    (cdr new-range)))
+
+
+
 ;;;###autoload
 (defun gnus-sorted-difference (list1 list2)
   "Return a list of elements of LIST1 that do not appear in LIST2.
@@ -433,7 +475,7 @@ LIST is a sorted list."
 		 (if (numberp (car ranges))
 		      (= (car ranges) number)
 		   ;; (caar ranges) <= number <= (cdar ranges)
-		   (>= number (caar ranges))))  
+		   (>= number (caar ranges))))
 	(push number result)))
     (nreverse result)))
 
@@ -460,7 +502,16 @@ LIST is a sorted list."
 
 (defun gnus-range-length (range)
   "Return the length RANGE would have if uncompressed."
-  (length (gnus-uncompress-range range)))
+  (cond
+   ((null range)
+    0)
+   ((not (listp (cdr range)))
+    (- (cdr range) (car range) -1))
+   (t
+    (let ((sum 0))
+      (dolist (x range sum)
+	(setq sum
+	      (+ sum (if (consp x) (- (cdr x) (car x) -1) 1))))))))
 
 (defun gnus-sublist-p (list sublist)
   "Test whether all elements in SUBLIST are members of LIST."
@@ -526,6 +577,18 @@ LIST is a sorted list."
     (if item (push item range))
     (reverse range)))
 
+;;;###autoload
+(defun gnus-add-to-sorted-list (list num)
+  "Add NUM into sorted LIST by side effect."
+  (let* ((top (cons nil list))
+	 (prev top))
+    (while (and list (< (car list) num))
+      (setq prev list
+	    list (cdr list)))
+    (unless (eq (car list) num)
+      (setcdr prev (cons num list)))
+    (cdr top)))
+
 (provide 'gnus-range)
 
 ;;; gnus-range.el ends here