--- gnus-cache.el	01 Mar 2008 22:54:54 +0100	6.26.2.13
+++ gnus-cache.el	19 Apr 2008 16:01:26 +0200	
@@ -501,10 +501,14 @@
 	  (setq gnus-cache-active-altered t)))
       articles)))
 
+
 (defun gnus-cache-braid-nov (group cached &optional file)
+  (message "Merging cached articles with ones on server...")
   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*"))
-	beg end)
+        (new-records nil)
+	beg end server-cursor)
     (gnus-cache-save-buffers)
+    ;; create new buffer for reading cache overview
     (save-excursion
       (set-buffer cache-buf)
       (erase-buffer)
@@ -513,27 +517,58 @@
 	(insert-file-contents
 	 (or file (gnus-cache-file-name group ".overview"))))
       (goto-char (point-min))
-      (insert "\n")
+      (insert "\n") ; so we can search for, e.g., \n123\t
       (goto-char (point-min)))
     (set-buffer nntp-server-buffer)
     (goto-char (point-min))
+    (setq server-cursor (point))
     (while cached
+      (set-buffer nntp-server-buffer)
+      ;; skip server records preceding first cached article
       (while (and (not (eobp))
 		  (< (read (current-buffer)) (car cached)))
 	(forward-line 1))
       (beginning-of-line)
+      ;; grab those records for the new buffer
+      (let ((new-server-cursor (point)))
+        (when (> new-server-cursor server-cursor)
+          (push (buffer-substring server-cursor new-server-cursor) new-records)
+          (setq server-cursor new-server-cursor)))
+      ;; grab first cached article, if present
       (set-buffer cache-buf)
       (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
 			  nil t)
 	  (setq beg (gnus-point-at-bol)
 		end (progn (end-of-line) (point)))
 	(setq beg nil))
-      (set-buffer nntp-server-buffer)
+      ;; grab that article's data for new buffer
       (when beg
-	(insert-buffer-substring cache-buf beg end)
-	(insert "\n"))
+        (push (buffer-substring beg end) new-records)
+        (push "\n" new-records))
       (setq cached (cdr cached)))
-    (kill-buffer cache-buf)))
+    ;; we're finished with the cache overview now
+    (kill-buffer cache-buf)
+    ;; grab any remaining stuff from old server buffer for new one
+    (set-buffer nntp-server-buffer)
+    (let ((new-server-cursor (point-max)))
+      (when (> new-server-cursor server-cursor)
+        (push (buffer-substring server-cursor new-server-cursor) new-records)))
+    ;; reverse chunks and concatenate
+    (let ((n 0) (records new-records))
+      (while records
+        (incf n (length (car records)))
+        (setq records (cdr records)))
+      (let ((new-content (make-string n ?.)))
+        (setq n 0)
+        (setq records (nreverse new-records))
+        (setf new-records nil) ; help the GC a little
+        (while records
+          (store-substring new-content n (car records))
+          (incf n (length (car records)))
+          (setq records (cdr records)))
+        (set-buffer nntp-server-buffer)
+        (erase-buffer)
+        (insert new-content))) ))
 
 (defun gnus-cache-braid-heads (group cached)
   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*")))