From 9dd7af89584a7acb525ed2c3a4fbd88f2014dfd4 Mon Sep 17 00:00:00 2001
From: yamaoka <yamaoka>
Date: Mon, 25 Nov 2002 22:27:59 +0000
Subject: [PATCH] Synch with Oort Gnus.

---
 lisp/ChangeLog     |    6 ++++++
 lisp/gnus-range.el |   42 ++++++++++++++++++++++++++++++++++++++++++
 lisp/gnus-sum.el   |    3 ++-
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 9f21bee..e06ddcd 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2002-11-25  Kai Gro,A_(Bjohann  <kai.grossjohann@uni-duisburg.de>
+	From Kevin Greiner <kgreiner@xpediantsolutions.com>.
+
+	* gnus-range.el (gnus-range-difference): New function.
+	* gnus-sum.el (gnus-summary-insert-old-articles): Use it.
+
 2002-11-24  Kai Gro,A_(Bjohann  <kai.grossjohann@uni-duisburg.de>
 
 	* gnus-sum.el (gnus-summary-insert-old-articles): Use
diff --git a/lisp/gnus-range.el b/lisp/gnus-range.el
index b609074..2e0a988 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.
diff --git a/lisp/gnus-sum.el b/lisp/gnus-sum.el
index 952b901..1fabdbd 100644
--- a/lisp/gnus-sum.el
+++ b/lisp/gnus-sum.el
@@ -11505,7 +11505,8 @@ If ALL is a number, fetch this number of articles."
 ;;;	      (gnus-sorted-difference
 ;;;	       (gnus-uncompress-range (list gnus-newsgroup-active))
 ;;;	       old)
-	      (gnus-remove-from-range (list gnus-newsgroup-active) old)
+	      (gnus-range-difference
+	       (gnus-remove-from-range (list gnus-newsgroup-active) old))
 )
 	(setq len (gnus-range-length older))
 	(cond
-- 
1.7.10.4