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+;;; ediff-diff.el --- diff-related utilities
+;;; Copyright (C) 1994 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+(require 'ediff-init)
+
+
+(defvar ediff-shell
+  (cond ((eq system-type 'emx) "cmd") ; OS/2
+	((memq system-type '(vax-vms axp-vms)) "*dcl*") ; VMS
+	(t  "sh")) ; UNIX
+  "*The shell used to run diff and patch.  If user's .profile or
+.cshrc files are set up correctly, any shell will do.  However, some people
+set $prompt or other things incorrectly, which leads to undesirable output
+messages.  These may cause Ediff to fail.  In such a case, set ediff-shell
+to a shell that you are not using or, better, fix your shell's startup file.")
+
+
+(defvar ediff-diff-program "diff"
+  "*Program to use for generating the differential of the two files.")
+(defvar ediff-diff-options ""  
+  "*Options to pass to `ediff-diff-program'. 
+If diff\(1\) is used as `ediff-diff-program', then the most useful options are
+`-w', to ignore space, and `-i', to ignore case of letters.
+At present, the option `-c' is ignored, since Ediff doesn't understand this
+type of output.")
+
+(defvar ediff-custom-diff-program ediff-diff-program
+  "*Program to use for generating custom diff output for saving it in a file.
+This output is not used by Ediff internally.")
+(defvar ediff-custom-diff-options "-c"
+  "*Options to pass to `ediff-custom-diff-program'.")
+
+;;; Support for diff3
+
+(defvar ediff-match-diff3-line "^====\\(.?\\)$"
+  "Pattern to match lines produced by diff3 that describe differences.")
+(defvar ediff-diff3-program "diff3"
+  "*Program to be used for three-way comparison.
+Must produce output compatible with Unix's diff3 program.")
+(defvar ediff-diff3-options ""  
+  "*Options to pass to `ediff-diff3-program'.")
+(defvar ediff-diff3-ok-lines-regexp
+  "^\\([1-3]:\\|====\\|  \\|.*Warning *:\\|.*No newline\\|.*missing newline\\)"
+  "*Regexp that matches normal output lines from `ediff-diff3-program'.
+Lines that do not match are assumed to be error messages.")
+
+;; keeps the status of the current diff in 3-way jobs.
+;; the status can be =diff(A), =diff(B), or =diff(A+B)
+(ediff-defvar-local ediff-diff-status "" "")
+
+;; Support for patch 
+
+(defvar ediff-patch-program "patch"
+  "*Name of the program that applies patches.")
+(defvar ediff-patch-options ""
+  "*Options to pass to ediff-patch-program.")
+
+;; The buffer of the patch file.
+(defvar ediff-patch-buf nil)
+;; The buffer where patch would display its diagnostics.
+(defvar ediff-patch-diagnostics nil)
+
+  
+;;; Fine differences 
+
+(ediff-defvar-local ediff-auto-refine (if window-system 'on 'nix)
+  "If `on', Ediff auto-highlights fine diffs for the current diff region.
+If `off', auto-highlighting is not used. If `nix', no fine diffs are shown
+at all, unless the user force-refines the region by hitting `*'.
+
+This variable can be set either in .emacs or toggled interactively.
+Use `setq-default' if setting it in .emacs")
+
+(ediff-defvar-local ediff-ignore-similar-regions nil
+  "*If t, skip over difference regions that differ only in the white space and line breaks.
+This variable can be set either in .emacs or toggled interactively.
+Use `setq-default' if setting it in .emacs")
+
+(ediff-defvar-local ediff-auto-refine-limit 700
+  "Auto-refine only those regions that are smaller than this number of bytes.")
+  
+;;; General
+
+(defvar ediff-diff-ok-lines-regexp  
+  "^\\([0-9,]+[acd][0-9,]+$\\|[<>] \\|---\\|.*Warning *:\\|.*No newline\\|.*missing newline\\)"
+  "Regexp that matches normal output lines from `ediff-diff-program'.
+This is mostly lifted from Emerge, except that Ediff also considers
+warnings and `Missing newline'-type messages to be normal output.
+Lines that do not match are assumed to be error messages.")
+
+(defvar ediff-match-diff-line (let ((x "\\([0-9]+\\)\\(\\|,\\([0-9]+\\)\\)"))
+				(concat "^" x "\\([acd]\\)" x "$"))
+  "Pattern to match lines produced by diff that describe differences.")
+
+(ediff-defvar-local ediff-setup-diff-regions-function nil
+  "value is a function symbol depending on the kind of job is to be done.
+For 2-way jobs and for ediff-merge, it should be `ediff-setup-diff-regions'.
+For jobs requiring diff3, it should be `ediff-setup-diff-regions3'.
+
+The function should take three mandatory arguments, file-A, file-B, and
+file-C. It may ignore file C for diff2 jobs. It should also take
+one optional arguments, diff-number to refine.")
+
+  
+  
+;;; Functions
+
+;; Generate the difference vector and overlays for the two files
+;; With optional arg REG-TO-REFINE, refine this region.
+;; File-C argument is not used here. It is there just because
+;; ediff-setup-diff-regions is called via a funcall to
+;; ediff-setup-diff-regions-function, which can also have the value
+;; ediff-setup-diff-regions3, which takes 4 arguments.
+(defun ediff-setup-diff-regions (file-A file-B file-C)
+  ;; force all minibuffers to display ediff's messages.
+  ;; when xemacs implements minibufferless screens, this won't be necessary
+  (if ediff-xemacs-p (setq synchronize-minibuffers t))
+						  
+  (or (ediff-buffer-live-p ediff-diff-buffer)
+      (setq ediff-diff-buffer
+	    (get-buffer-create (ediff-unique-buffer-name "*ediff-diff" "*"))))
+  (or (ediff-buffer-live-p ediff-custom-diff-buffer)
+      (setq ediff-custom-diff-buffer
+	    (get-buffer-create
+	     (ediff-unique-buffer-name "*ediff-custom-diff" "*"))))
+  
+  (ediff-eval-in-buffer ediff-diff-buffer
+    (erase-buffer)
+    ;; shell-command tends to display old shell command buffers even when it
+    ;; puts output in another buffer---probably an Emacs bug.
+    (ediff-kill-buffer-carefully "*Shell Command Output*")
+    (let ((shell-file-name ediff-shell))
+      (message "Computing differences ...") (sit-for 0)
+      (shell-command
+       (format "%s %s %s %s"
+	       ediff-diff-program ediff-diff-options
+	       (ediff-protect-metachars file-A)
+	       (ediff-protect-metachars file-B))
+       t)
+      ))
+  
+  ;; compute custom diffs
+  (let ((shell-file-name ediff-shell)
+	(recomp-diff-key
+	 (string-to-char
+	  (substitute-command-keys "\\[ediff-update-diffs]"))))
+    (if (or (= (buffer-size) 0)  ; was the first time
+	    (eq last-command-char recomp-diff-key)) ; was a recompute cmd
+	;; do asynchronously & insert output in ediff-custom-diff-buffer
+	(ediff-shell-command
+	 (format "%s %s %s %s"
+		 ediff-custom-diff-program ediff-custom-diff-options
+		 (ediff-protect-metachars file-A)
+		 (ediff-protect-metachars file-B))
+	 ediff-custom-diff-buffer)))
+  
+  (ediff-prepare-error-list ediff-diff-ok-lines-regexp ediff-diff-buffer)
+  (message "Computing differences ... done")(sit-for 0)
+  (ediff-convert-diffs-to-overlays
+   (ediff-extract-diffs
+    ediff-diff-buffer ediff-word-mode ediff-narrow-bounds))
+  )
+     
+;; If file-A/B/C is nil, do 2-way comparison with the non-nil buffers
+;; This function works for diff3 and diff2 jobs
+(defun ediff-setup-fine-diff-regions (file-A file-B file-C reg-num)
+  (or (ediff-buffer-live-p ediff-fine-diff-buffer)
+      (setq ediff-fine-diff-buffer
+	    (get-buffer-create
+	     (ediff-unique-buffer-name "*ediff-fine-diff" "*"))))
+  
+  (let (diff3-job diff-program diff-options ok-regexp diff-list)
+    (setq diff3-job ediff-3way-job
+	  diff-program (if diff3-job ediff-diff3-program ediff-diff-program)
+	  diff-options ""
+	  ok-regexp (if diff3-job
+			ediff-diff3-ok-lines-regexp
+			ediff-diff-ok-lines-regexp))
+    
+    (ediff-eval-in-buffer ediff-fine-diff-buffer
+      (erase-buffer)
+      ;; shell-command tends to display old shell command buffers even when
+      ;; it puts output in another buffer---probably an Emacs bug.
+      (ediff-kill-buffer-carefully "*Shell Command Output*")
+      (let ((shell-file-name ediff-shell))
+	(message "Refining difference region %d ..." (1+ reg-num))
+	(shell-command
+	 (format "%s %s %s %s %s"
+		 diff-program diff-options 
+		 (if file-A 
+		     (ediff-protect-metachars file-A) 
+		   (ediff-protect-metachars file-B))
+		 (if file-B
+		     (ediff-protect-metachars file-B) 
+		   (ediff-protect-metachars file-A))
+		 (if diff3-job
+		     (if file-C 
+			 (ediff-protect-metachars file-C) 
+		       (ediff-protect-metachars file-B))
+		   "")
+		 )
+	 t)
+	))
+  
+    (ediff-prepare-error-list ok-regexp ediff-fine-diff-buffer)
+    (message "Refining difference region %d ... done" (1+ reg-num))
+    
+    (setq diff-list
+	  (if diff3-job
+	      (ediff-extract-diffs3
+	       ediff-fine-diff-buffer '3way-comparison 'word-mode)
+	    (ediff-extract-diffs ediff-fine-diff-buffer 'word-mode)))
+    ;; fixup diff-list
+    (if diff3-job
+	(cond ((not file-A)
+	       (mapcar (function (lambda (elt)
+				   (aset elt 0 nil)
+				   (aset elt 1 nil)))
+		       (cdr diff-list)))
+	      ((not file-B)
+	       (mapcar (function (lambda (elt)
+				   (aset elt 2 nil)
+				   (aset elt 3 nil)))
+		       (cdr diff-list)))
+	      ((not file-C)
+	       (mapcar (function (lambda (elt)
+				   (aset elt 4 nil)
+				   (aset elt 5 nil)))
+		       (cdr diff-list)))
+	  ))
+    
+    (ediff-convert-fine-diffs-to-overlays diff-list reg-num)
+    ))
+  
+    
+(defun ediff-prepare-error-list (ok-regexp diff-buff)
+    (ediff-eval-in-buffer ediff-error-buffer
+      (erase-buffer)
+      (insert-buffer diff-buff)
+      (delete-matching-lines ok-regexp)
+      (if (memq system-type '(vax-vms axp-vms))
+	  (delete-matching-lines "^$")))
+    ;; If diff reports errors, show them then quit.
+    (if (/= 0 (ediff-eval-in-buffer ediff-error-buffer (buffer-size)))
+	(let ((ctl-buf ediff-control-buffer)
+	      (error-buf ediff-error-buffer))
+	  (ediff-skip-unsuitable-frames)
+	  (switch-to-buffer error-buf)
+	  (ediff-kill-buffer-carefully ctl-buf)
+	  (error "Errors in diff output. Diff output is in %S" diff-buff))))
+
+;; BOUNDS specifies visibility bounds to use.
+;; WORD-MODE tells whether we are in the word-mode or not.
+;; If WORD-MODE, also construct vector of diffs using word numbers.
+;; Else, use point values.
+;; This function handles diff-2 jobs including the case of
+;; merging buffers and files without ancestor.
+(defun ediff-extract-diffs (diff-buffer word-mode &optional bounds)
+  (let ((A-buffer ediff-buffer-A)
+	(B-buffer ediff-buffer-B)
+	(C-buffer ediff-buffer-C)
+	(a-prev 1) ; this is needed to set the first diff line correctly
+	(b-prev 1)
+	(c-prev 1)
+	diff-list shift-A shift-B
+	)
+ 
+    ;; diff list contains word numbers, unless changed later
+    (setq diff-list (cons (if word-mode 'words 'points)
+			  diff-list))
+    ;; we don't use visibility bounds for buffer C when merging
+    (if bounds
+	(setq shift-A
+	      (ediff-overlay-start
+	       (ediff-get-value-according-to-buffer-type 'A bounds))
+	      shift-B 
+	      (ediff-overlay-start
+	       (ediff-get-value-according-to-buffer-type 'B bounds))))
+    
+    ;; reset point in buffers A/B/C
+    (ediff-eval-in-buffer A-buffer
+      (goto-char (if shift-A shift-A (point-min))))
+    (ediff-eval-in-buffer B-buffer
+      (goto-char (if shift-B shift-B (point-min))))
+    (if (ediff-buffer-live-p C-buffer)
+	(ediff-eval-in-buffer C-buffer
+	  (goto-char (point-min))))
+    
+    (ediff-eval-in-buffer diff-buffer
+      (goto-char (point-min))
+      (while (re-search-forward ediff-match-diff-line nil t)
+       (let* ((a-begin (string-to-int (buffer-substring (match-beginning 1)
+							(match-end 1))))
+	      (a-end  (let ((b (match-beginning 3))
+			    (e (match-end 3)))
+			(if b
+			    (string-to-int (buffer-substring b e))
+			  a-begin)))
+	      (diff-type (buffer-substring (match-beginning 4) (match-end 4)))
+	      (b-begin (string-to-int (buffer-substring (match-beginning 5)
+							(match-end 5))))
+	      (b-end (let ((b (match-beginning 7))
+			   (e (match-end 7)))
+		       (if b
+			   (string-to-int (buffer-substring b e))
+			 b-begin)))
+	      a-begin-pt a-end-pt b-begin-pt b-end-pt
+	      c-begin c-end c-begin-pt c-end-pt)
+	 ;; fix the beginning and end numbers, because diff is somewhat
+	 ;; strange about how it numbers lines
+	 (if (string-equal diff-type "a")
+	     (setq b-end (1+ b-end)
+		   a-begin (1+ a-begin)
+		   a-end a-begin)
+	   (if (string-equal diff-type "d")
+	       (setq a-end (1+ a-end)
+		     b-begin (1+ b-begin)
+		     b-end b-begin)
+	     ;; (string-equal diff-type "c")
+	     (setq a-end (1+ a-end)
+		   b-end (1+ b-end))))
+		   
+	 (if (eq ediff-default-variant 'default-B)
+	     (setq c-begin b-begin
+		   c-end b-end)
+	   (setq c-begin a-begin
+		 c-end a-end))
+	 
+	 ;; compute main diff vector
+	 (if word-mode
+	     ;; make diff-list contain word numbers
+	     (setq diff-list 
+		   (nconc diff-list
+			  (list
+			   (if (ediff-buffer-live-p C-buffer)
+			       (vector (- a-begin a-prev) (- a-end a-begin)
+				       (- b-begin b-prev) (- b-end b-begin)
+				       (- c-begin c-prev) (- c-end c-begin)
+				       nil ; state of diff
+				       nil ; state of merge
+				       )
+			     (vector (- a-begin a-prev) (- a-end a-begin)
+				     (- b-begin b-prev) (- b-end b-begin)
+				     nil nil ; dummy buf C
+				     nil     ; state of diff
+				     nil     ; state of merge
+				     ))
+			   ))
+		   a-prev a-end
+		   b-prev b-end
+		   c-prev c-end)
+	   ;; else convert lines to points
+	   (ediff-eval-in-buffer A-buffer
+	     (forward-line (- a-begin a-prev))
+	     (setq a-begin-pt (point))
+	     (forward-line (- a-end a-begin))
+	     (setq a-end-pt (point)
+		   a-prev a-end))
+	   (ediff-eval-in-buffer B-buffer
+	     (forward-line (- b-begin b-prev))
+	     (setq b-begin-pt (point))
+	     (forward-line (- b-end b-begin))
+	     (setq b-end-pt (point)
+		   b-prev b-end))
+	   (if (ediff-buffer-live-p C-buffer)
+	       (ediff-eval-in-buffer C-buffer
+		 (forward-line (- c-begin c-prev))
+		 (setq c-begin-pt (point))
+		 (forward-line (- c-end c-begin))
+		 (setq c-end-pt (point)
+		       c-prev c-end)))
+	   (setq diff-list 
+		 (nconc
+		  diff-list
+		  (list
+		   (if (ediff-buffer-live-p C-buffer)
+		       (vector
+			a-begin-pt a-end-pt b-begin-pt b-end-pt
+			c-begin-pt c-end-pt
+			;; state of diff
+			;; shows which buff is different from the other two
+			(if (eq ediff-default-variant 'default-B) 'A 'B)
+			;; state of merge
+			ediff-default-variant
+			)
+		     (vector a-begin-pt a-end-pt b-begin-pt b-end-pt
+			     nil nil ; dummy buf C
+			     nil nil ; dummy state of diff & merge
+			     ))) 
+		  )))
+		  
+	 ))) ; end ediff-eval-in-buffer
+    diff-list
+    ))
+    
+
+(defun ediff-set-diff-overlays-in-one-buffer (buf-type diff-list)
+  (let* ((current-diff -1)
+	 (buff (ediff-get-buffer buf-type))
+	 ;; ediff-extract-diffs puts the type of diff-list as the first elt
+	 ;; of this list. The type is either 'points or 'words
+	 (diff-list-type (car diff-list))
+	 (shift (ediff-overlay-start
+		 (ediff-get-value-according-to-buffer-type
+		  buf-type ediff-narrow-bounds)))
+	 (limit (ediff-overlay-end
+		 (ediff-get-value-according-to-buffer-type 
+		  buf-type ediff-narrow-bounds)))
+	 diff-overlay-list list-element total-diffs
+	 begin end pt-saved overlay state-of-diff state-of-merge)
+
+    (setq diff-list (cdr diff-list)) ; discard diff list type
+    (setq total-diffs (length diff-list))
+      
+    ;; shift, if necessary
+    (ediff-eval-in-buffer buff (setq pt-saved shift))
+	   
+    (while diff-list
+      (setq current-diff (1+ current-diff)
+	    list-element (car diff-list)
+	    begin 	 (aref list-element (cond ((eq buf-type 'A) 0)
+						  ((eq buf-type 'B) 2)
+						  (t 4)))  ; buff C
+	    end 	 (aref list-element (cond ((eq buf-type 'A) 1)
+						  ((eq buf-type 'B) 3)
+						  (t 5)))  ; buff C
+	    state-of-diff (aref list-element 6)
+	    state-of-merge (aref list-element 7))
+		
+      (cond ((and (not (eq buf-type state-of-diff))
+		  (memq state-of-diff '(A B C)))
+	     (setq state-of-diff
+		   (car (delq buf-type (delq state-of-diff (list 'A 'B 'C)))))
+	     (setq state-of-diff (format "=diff(%S)" state-of-diff))
+	     (if (and ediff-merge-job state-of-merge (eq buf-type 'C))
+		 (setq state-of-merge (format "%S" state-of-merge)))
+	     )
+	    (t (setq state-of-diff nil
+		     state-of-merge nil)))
+	    
+      ;; Put overlays at appropriate places in buffer
+      ;; convert word numbers to points, if necessary
+      (if (eq diff-list-type 'words)
+	  (progn
+	    (ediff-eval-in-buffer buff (goto-char pt-saved))
+	    (setq begin (ediff-goto-word (1+ begin) buff)
+		  end (ediff-goto-word end buff 'end))
+	    (if (> end limit) (setq end limit))
+	    (if (> begin end) (setq begin end))
+	    (setq pt-saved (ediff-eval-in-buffer buff (point)))))
+      (setq overlay (ediff-make-bullet-proof-overlay begin end buff))
+      
+      ;; Priorities of overlays should be equal in all ediff control
+      ;; panel buffers. Otherwise it won't work due to Emacs
+      ;; bug, as insert-in-front-hooks will be called 
+      ;; only on behalf of the buffer with higher priority.
+      (ediff-overlay-put overlay 'priority ediff-shadow-overlay-priority)
+      (ediff-overlay-put overlay 'ediff-diff-num current-diff)
+      (ediff-overlay-put 
+       overlay 'insert-in-front-hooks '(ediff-insert-in-front))
+      (ediff-overlay-put
+       overlay 'face (if (ediff-odd-p current-diff)
+			 (intern 
+			  (format "ediff-odd-diff-face-%S-var" buf-type))
+		       (intern
+			(format "ediff-even-diff-face-%S-var" buf-type))))
+
+      (if (= 0 (mod current-diff 10))
+	  (message "Buffer %S: Processing difference region %d of %d"
+		   buf-type current-diff total-diffs))
+      ;; record all overlays for this difference
+      ;; the second elt, nill, is a place holder for the fine diff vector.
+      ;; the last nil is a place holder for no-fine-diffs flag.
+      (setq diff-overlay-list
+	    (nconc
+	     diff-overlay-list
+	     (list (vector overlay nil nil state-of-diff state-of-merge)))
+	    diff-list
+	    (cdr diff-list))
+      ) ; while
+      
+    (set (intern (format "ediff-difference-vector-%S" buf-type))
+	 (apply 'vector diff-overlay-list))
+    ))
+	 
+;; `n' is the diff region to work on.  Default is ediff-current-difference.
+;; if `flag' is 'noforce then make fine-diffs only if this region's fine
+;; diffs have not been computed before.
+;; if `flag' is 'skip then don't compute fine diffs for this region.
+;;
+(defun ediff-make-fine-diffs (&optional n flag)       
+  (or n  (setq n ediff-current-difference))
+  
+  (if (< ediff-number-of-differences 1)
+      (error "No differences found"))
+      
+  (if ediff-word-mode
+      (setq flag 'skip
+	    ediff-auto-refine 'nix))
+  
+  (or (< n 0)
+      (>= n ediff-number-of-differences)
+      ;; n is within the range
+      (let ((tmp-buffer (get-buffer-create ediff-tmp-buffer))
+	    (file-A ediff-temp-file-A)
+	    (file-B ediff-temp-file-B)
+	    (file-C ediff-temp-file-C)
+	    (empty-A (ediff-empty-diff-region-p n 'A))
+	    (empty-B (ediff-empty-diff-region-p n 'B))
+	    (empty-C (ediff-empty-diff-region-p n 'C))
+	    (whitespace-A (ediff-whitespace-diff-region-p n 'A))
+	    (whitespace-B (ediff-whitespace-diff-region-p n 'B))
+	    (whitespace-C (ediff-whitespace-diff-region-p n 'C))
+	    cumulative-fine-diff-length)
+	
+	(cond ((and (eq flag 'noforce) (ediff-get-fine-diff-vector n 'A))
+	       ;; don't compute fine diffs if diff vector exists
+	       (if (and (ediff-no-fine-diffs-p n) ediff-verbose-p)
+		   (message "Only white-space differences in region %d"
+			    (1+ n))))
+	      ;; if one of the regions is empty (or 2 in 3way comparison
+	      ;; then don't refine
+	      ((> (length (delq nil (list empty-A empty-B empty-C))) 1)
+	       (if (and (ediff-looks-like-combined-merge n)
+			ediff-merge-job)
+		   (ediff-set-fine-overlays-in-one-buffer 'C nil n))
+	       (if ediff-verbose-p
+		   (if ediff-3way-comparison-job
+		       (message
+			"Region %d is empty in all buffers but %S"
+			(1+ n) 
+			(cond ((not empty-A) 'A)
+			      ((not empty-B) 'B)
+			      ((not empty-C) 'C)))
+		     (message
+		      "Region %d in buffer %S is empty"
+		      (1+ n) 
+		      (cond (empty-A 'A)
+			    (empty-B 'B)
+			    (empty-C 'C)))
+		     ))
+	       ;; if all regions happen to be empty, say, as a result of
+	       ;; deletions from non-empty regions, then mark as space only
+	       (if (and empty-A empty-B empty-C)
+		   (ediff-mark-diff-as-space-only n t)
+		 (ediff-mark-diff-as-space-only n nil)))
+	      ;; don't compute fine diffs for this region
+	      ((eq flag 'skip)
+	       (or (ediff-get-fine-diff-vector n 'A)
+		   (memq ediff-auto-refine '(off nix))
+		   (not ediff-verbose-p)
+		   (message
+		    "Region %d exceeds auto-refine limit. `%s' force-refines"
+		    (1+ n)
+		    (substitute-command-keys "\\[ediff-make-or-kill-fine-diffs]")
+		    )))
+	      (t
+	       ;; delete old fine diffs
+	       ;;(ediff-clear-fine-differences n)
+	       ;; recompute fine diffs
+	       (ediff-wordify
+		(ediff-get-diff-posn 'A 'beg n)
+		(ediff-get-diff-posn 'A 'end n)
+		ediff-buffer-A
+		tmp-buffer
+		ediff-control-buffer)
+	       (ediff-eval-in-buffer tmp-buffer
+		 (setq file-A (ediff-make-temp-file "fineDiffA" file-A)))
+	       
+	       (ediff-wordify
+		(ediff-get-diff-posn 'B 'beg n)
+		(ediff-get-diff-posn 'B 'end n)
+		ediff-buffer-B
+		tmp-buffer
+		ediff-control-buffer)
+	       (ediff-eval-in-buffer tmp-buffer
+		 (setq file-B (ediff-make-temp-file "fineDiffB" file-B)))
+		 
+	       (if ediff-3way-job
+		   (progn
+		     (ediff-wordify
+		      (ediff-get-diff-posn 'C 'beg n)
+		      (ediff-get-diff-posn 'C 'end n)
+		      ediff-buffer-C
+		      tmp-buffer
+		      ediff-control-buffer)
+		     (ediff-eval-in-buffer tmp-buffer
+		       (setq file-C
+			     (ediff-make-temp-file "fineDiffC" file-C)))))
+	       
+	       ;; save temp file names.
+	       (setq ediff-temp-file-A file-A
+		     ediff-temp-file-B file-B
+		     ediff-temp-file-C file-C)
+	       
+	       ;; set the new vector of fine diffs, if none exists
+	       (cond ((and ediff-3way-job whitespace-A)
+		      (ediff-setup-fine-diff-regions nil file-B file-C n))
+		     ((and ediff-3way-job whitespace-B)
+		      (ediff-setup-fine-diff-regions file-A nil file-C n))
+		     ((and ediff-3way-job
+			   (or whitespace-C
+			       (and ediff-merge-job
+				    (ediff-looks-like-combined-merge n))))
+		      (ediff-setup-fine-diff-regions file-A file-B nil n))
+		     (t
+		      (ediff-setup-fine-diff-regions file-A file-B file-C n)))
+		      
+	       (setq cumulative-fine-diff-length
+		     (+ (length (ediff-get-fine-diff-vector n 'A))
+				   (length (ediff-get-fine-diff-vector n 'B))
+				   (if file-C
+				       (length
+					(ediff-get-fine-diff-vector n 'C))
+				     0)))
+		      
+	       (cond ((or
+		       ;; all regions are white space
+		       (and whitespace-A whitespace-B whitespace-C)
+		       ;; none is white space and no fine diffs detected
+		       (and (not whitespace-A)
+			    (not whitespace-B)
+			    (not (and ediff-3way-job whitespace-C))
+			    (eq cumulative-fine-diff-length 0)))
+		      (ediff-mark-diff-as-space-only n t)
+		      (message
+		       "Only white-space differences in region %d" (1+ n)))
+		     ((eq cumulative-fine-diff-length 0)
+		      (ediff-mark-diff-as-space-only n nil)
+		      (message
+		       "Only white-space differences in region %d %s"
+		       (1+ n)
+		       (cond (whitespace-A "in buffers B & C")
+			     (whitespace-B "in buffers A & C")
+			     (whitespace-C "in buffers A & B"))))
+		     (t 
+		      (ediff-mark-diff-as-space-only n nil)))
+	       )
+	      ) ; end cond
+	(ediff-set-fine-diff-properties n)
+	)))
+	
+;; Interface to ediff-make-fine-diffs. Checks for auto-refine limit, etc.
+(defun ediff-install-fine-diff-if-necessary (n)
+  (cond ((eq ediff-auto-refine 'on)
+	 (if (and
+	      (> ediff-auto-refine-limit
+		 (- (ediff-get-diff-posn 'A 'end n)
+		    (ediff-get-diff-posn 'A 'beg n)))
+	      (> ediff-auto-refine-limit
+		 (- (ediff-get-diff-posn 'B 'end n)
+		    (ediff-get-diff-posn 'B 'beg n))))
+	     (ediff-make-fine-diffs n 'noforce)
+	   (ediff-make-fine-diffs n 'skip)))
+	
+	;; highlight iff fine diffs already exist
+	((eq ediff-auto-refine 'off)
+	 (ediff-make-fine-diffs n 'skip))))
+    
+    
+;; if fine diff vector is not set for diff N, then do nothing
+(defun ediff-set-fine-diff-properties (n &optional default)
+  (or (not window-system)
+      (< n 0)
+      (>= n ediff-number-of-differences)
+      ;; in a window system, set faces and priorities of fine overlays
+      (progn
+	(ediff-set-fine-diff-properties-in-one-buffer 'A n default)
+	(ediff-set-fine-diff-properties-in-one-buffer 'B n default)
+	(if ediff-3way-job
+	    (ediff-set-fine-diff-properties-in-one-buffer 'C n default)))))
+	
+(defun ediff-set-fine-diff-properties-in-one-buffer (buf-type
+						     n &optional default)
+  (let ((fine-diff-vector  (ediff-get-fine-diff-vector n buf-type))
+	(face (if default 
+		  'default
+		(face-name
+		 (intern (format "ediff-fine-diff-face-%S" buf-type)))))
+;;		(if (and (eq buf-type 'C)
+;;			 (ediff-looks-like-combined-merge n))
+;;		    'ediff-combined-diff-face
+;;		  (face-name
+;;		   (intern (format "ediff-fine-diff-face-%S" buf-type))))))
+	(priority (if default
+		      0
+		    (1+ (or (ediff-overlay-get
+			     (symbol-value
+			      (intern
+			       (format
+				"ediff-current-diff-overlay-%S" buf-type)))
+			     'priority)
+			    0)))))
+    (mapcar
+     (function (lambda (overl)
+		 (ediff-overlay-put overl 'face face)
+		 (ediff-overlay-put overl 'priority priority)))
+     fine-diff-vector)))
+     
+;; This assumes buffer C and that the region looks like a combination of
+;; regions in buffer A and C.
+(defun ediff-set-fine-overlays-for-combined-merge (diff-list reg-num)
+  (let (overlay1 overlay2 overlay3)
+    (setq overlay1 (ediff-make-bullet-proof-overlay (nth 0 diff-list)
+						    (nth 1 diff-list)
+						    ediff-buffer-C)
+	  overlay2 (ediff-make-bullet-proof-overlay (nth 2 diff-list)
+						    (nth 3 diff-list)
+						    ediff-buffer-C)
+	  overlay3 (ediff-make-bullet-proof-overlay (nth 4 diff-list)
+						    (nth 5 diff-list)
+						    ediff-buffer-C))
+    (ediff-set-fine-diff-vector reg-num 'C (vector overlay1 overlay2 overlay3))
+    ))
+	
+    
+;; Convert diff list to overlays for a given DIFF-REGION
+;; in buffer of type BUF-TYPE
+(defun ediff-set-fine-overlays-in-one-buffer (buf-type diff-list region-num)
+  (let* ((current-diff -1)
+	 (reg-start (ediff-get-diff-posn buf-type 'beg region-num))
+	 (buff (ediff-get-buffer buf-type))
+	 combined-merge-diff-list
+	 diff-overlay-list list-element
+	 begin end overlay)
+
+    (ediff-clear-fine-differences-in-one-buffer region-num buf-type)
+    (setq diff-list (cdr diff-list)) ; discard list type (words or points)
+    (ediff-eval-in-buffer buff (goto-char reg-start))
+    
+    ;; if it is a combined merge then set overlays in buff C specially
+    (if (and ediff-merge-job (eq buf-type 'C)
+	     (setq combined-merge-diff-list
+		   (ediff-looks-like-combined-merge region-num)))
+	(ediff-set-fine-overlays-for-combined-merge
+	 combined-merge-diff-list region-num)
+      ;; regular fine diff
+      (while diff-list
+	(setq current-diff (1+ current-diff)
+	      list-element (car diff-list)
+	      begin 	 (aref list-element (cond ((eq buf-type 'A) 0)
+						  ((eq buf-type 'B) 2)
+						  (t 4)))  ; buf C
+	      end 	 (aref list-element (cond ((eq buf-type 'A) 1)
+						  ((eq buf-type 'B) 3)
+						  (t 5)))) ; buf C
+	(if (not (or begin end))
+	    () ; skip this diff
+	  ;; Put overlays at appropriate places in buffers
+	  ;; convert lines to points, if necessary
+	  (setq begin (ediff-goto-word (1+ begin) buff)
+		end (ediff-goto-word end buff 'end))
+	  (setq overlay (ediff-make-bullet-proof-overlay begin end buff))
+	  ;; record all overlays for this difference region
+	  (setq diff-overlay-list (nconc diff-overlay-list (list overlay))))
+	
+	(setq diff-list (cdr diff-list))
+	) ; while
+      ;; convert the list of difference information into a vector
+      ;; for fast access
+      (ediff-set-fine-diff-vector 
+       region-num buf-type (apply 'vector diff-overlay-list))
+      )))
+
+
+;; Stolen from emerge.el
+(defun ediff-get-diff3-group (file)
+  ;; This save-excursion allows ediff-get-diff3-group to be called for the
+  ;; various groups of lines (1, 2, 3) in any order, and for the lines to
+  ;; appear in any order.  The reason this is necessary is that Gnu diff3
+  ;; can produce the groups in the order 1, 2, 3 or 1, 3, 2.
+  (save-excursion
+    (re-search-forward
+     (concat "^" file ":\\([0-9]+\\)\\(,\\([0-9]+\\)\\)?\\([ac]\\)$"))
+    (beginning-of-line 2)
+    ;; treatment depends on whether it is an "a" group or a "c" group
+    (if (string-equal (buffer-substring (match-beginning 4) (match-end 4)) "c")
+	;; it is a "c" group
+	(if (match-beginning 2)
+	    ;; it has two numbers
+	    (list (string-to-int
+		   (buffer-substring (match-beginning 1) (match-end 1)))
+		  (1+ (string-to-int
+		       (buffer-substring (match-beginning 3) (match-end 3)))))
+	  ;; it has one number
+	  (let ((x (string-to-int
+		    (buffer-substring (match-beginning 1) (match-end 1)))))
+	    (list x (1+ x))))
+      ;; it is an "a" group
+      (let ((x (1+ (string-to-int
+		    (buffer-substring (match-beginning 1) (match-end 1))))))
+	(list x x)))))
+
+
+;; If WORD-MODE, construct vector of diffs using word numbers.
+;; Else, use point values.
+;; WORD-MODE also tells if we are in the word-mode or not.
+;; If THREE-WAY-COMP, then it is a 3-way comparison. Else, it is merging
+;; with ancestor, in which case buffer-C contents is identical to buffer-A
+;; contents (unless buffer-A is narrowed.
+;; BOUNDS specifies visibility bounds to use.
+(defun ediff-extract-diffs3 (diff-buffer word-mode three-way-comp
+					  &optional bounds)
+  (let ((A-buffer ediff-buffer-A)
+	(B-buffer ediff-buffer-B)
+	(C-buffer ediff-buffer-C)
+	(a-prev 1) ; needed to set the first diff line correctly
+	(b-prev 1)
+	(c-prev 1)
+	diff-list shift-A shift-B shift-C
+	)
+ 
+    ;; diff list contains word numbers or points, depending on word-mode
+    (setq diff-list (cons (if word-mode 'words 'points)
+			  diff-list))
+    (if bounds
+	(setq shift-A
+	      (ediff-overlay-start
+	       (ediff-get-value-according-to-buffer-type 'A bounds))
+	      shift-B 
+	      (ediff-overlay-start
+	       (ediff-get-value-according-to-buffer-type 'B bounds))
+	      shift-C 
+	      (if three-way-comp
+		  (ediff-overlay-start
+		   (ediff-get-value-according-to-buffer-type 'C bounds)))))
+    
+    ;; reset point in buffers A, B, C
+    (ediff-eval-in-buffer A-buffer
+      (goto-char (if shift-A shift-A (point-min))))
+    (ediff-eval-in-buffer B-buffer
+      (goto-char (if shift-B shift-B (point-min))))
+    (ediff-eval-in-buffer C-buffer
+      (goto-char (if shift-C shift-C (point-min))))
+    
+    (ediff-eval-in-buffer diff-buffer
+      (goto-char (point-min))
+      (while (re-search-forward ediff-match-diff3-line nil t)
+	;; leave point after matched line
+       (beginning-of-line 2)
+       (let ((agreement (buffer-substring (match-beginning 1) (match-end 1))))
+	 ;; if the A and B files are the same and not 3way-comparison,
+	 ;; ignore the difference
+	 (if (or three-way-comp (not (string-equal agreement "3")))
+	     (let* ((a-begin (car (ediff-get-diff3-group "1")))
+		    (a-end  (nth 1 (ediff-get-diff3-group "1")))
+		    (b-begin (car (ediff-get-diff3-group "2")))
+		    (b-end (nth 1 (ediff-get-diff3-group "2")))
+		    (state-of-merge
+		     (cond ((string-equal agreement "1") 'prefer-A)
+			   ((string-equal agreement "2") 'prefer-B)
+			   (t ediff-default-variant)))
+		    (state-of-diff-merge
+		     (if (memq state-of-merge '(default-A prefer-A)) 'B 'A))
+		    (state-of-diff-comparison
+		     (cond ((string-equal agreement "1") 'A)
+			   ((string-equal agreement "2") 'B)
+			   ((string-equal agreement "3") 'C)))
+		    c-begin c-end
+		    a-begin-pt a-end-pt
+		    b-begin-pt b-end-pt c-begin-pt c-end-pt)
+		    
+	       (if three-way-comp
+		   (setq c-begin (car (ediff-get-diff3-group "3"))
+			 c-end (nth 1 (ediff-get-diff3-group "3")))
+		 (if (eq ediff-default-variant 'default-B)
+		     (setq c-begin b-begin
+			   c-end b-end)
+		   (setq c-begin a-begin
+			 c-end a-end)))
+	 
+	       ;; compute main diff vector
+	       (if word-mode
+		   ;; make diff-list contain word numbers
+		   (setq diff-list 
+			 (nconc diff-list
+				(list (vector
+				       (- a-begin a-prev) (- a-end a-begin)
+				       (- b-begin b-prev) (- b-end b-begin)
+				       (- c-begin c-prev) (- c-end c-begin)
+				       nil nil))) ; state of diff & merge
+			 a-prev a-end
+			 b-prev b-end
+			 c-prev c-end)
+		 ;; else convert lines to points
+		 (ediff-eval-in-buffer A-buffer
+		   (forward-line (- a-begin a-prev))
+		   (setq a-begin-pt (point))
+		   (forward-line (- a-end a-begin))
+		   (setq a-end-pt (point)
+			 a-prev a-end))
+		 (ediff-eval-in-buffer B-buffer
+		   (forward-line (- b-begin b-prev))
+		   (setq b-begin-pt (point))
+		   (forward-line (- b-end b-begin))
+		   (setq b-end-pt (point)
+			 b-prev b-end))
+		 (ediff-eval-in-buffer C-buffer
+		   (forward-line (- c-begin c-prev))
+		   (setq c-begin-pt (point))
+		   (forward-line (- c-end c-begin))
+		   (setq c-end-pt (point)
+			 c-prev c-end))
+		 (setq diff-list 
+		       (nconc
+			diff-list
+			;; if comparing with ancestor, then there also is a
+			;; state-of-difference marker
+			(if three-way-comp
+			    (list (vector
+				   a-begin-pt a-end-pt
+				   b-begin-pt b-end-pt
+				   c-begin-pt c-end-pt
+				   state-of-diff-comparison
+				   nil           ; state of merge
+				   ))
+			  (list (vector a-begin-pt a-end-pt
+					b-begin-pt b-end-pt
+					c-begin-pt c-end-pt
+					state-of-diff-merge
+					state-of-merge
+					)))
+			)))
+	       ))
+	       
+	 ))) ; end ediff-eval-in-buffer
+    diff-list
+    ))
+    
+;; Generate the difference vector and overlays for three files
+;; File-C is either the third file to compare (in case of 3-way comparison)
+;; or it is the ancestor file.
+(defun ediff-setup-diff-regions3 (file-A file-B file-C)
+  
+  ;; force all minibuffers to display ediff's messages.
+  ;; when xemacs implements minibufferless screens, this won't be necessary
+  (if ediff-xemacs-p (setq synchronize-minibuffers t))
+						  
+  (or (ediff-buffer-live-p ediff-diff-buffer)
+      (setq ediff-diff-buffer
+	    (get-buffer-create (ediff-unique-buffer-name "*ediff-diff" "*"))))
+  
+  (ediff-eval-in-buffer ediff-diff-buffer
+    (erase-buffer)
+    ;; shell-command tends to display old shell command buffers even when it
+    ;; puts output in another buffer---probably an Emacs bug.
+    (ediff-kill-buffer-carefully "*Shell Command Output*")
+    (let ((shell-file-name ediff-shell))
+      (message "Computing differences ...")(sit-for 0)
+      (shell-command
+       (format "%s %s %s %s %s"
+	       ediff-diff3-program ediff-diff3-options
+	       (ediff-protect-metachars file-A)
+	       (ediff-protect-metachars file-B)
+	       (ediff-protect-metachars file-C))
+       t)
+      ))
+  
+  (ediff-prepare-error-list ediff-diff3-ok-lines-regexp ediff-diff-buffer)
+  (message "Computing differences ... done")(sit-for 0)
+  (ediff-convert-diffs-to-overlays
+   (ediff-extract-diffs3
+    ediff-diff-buffer
+    ediff-word-mode ediff-3way-comparison-job ediff-narrow-bounds)
+   ))
+   
+
+;; Execute shell COMMAND asynchronously and insert output in BUFFER.
+;; BUFFER must be a buffer object, and must be alive.
+;; There should be NO ampersand at the end of the command.
+;; We introduce this command because Emacs shell-command doesn't let us
+;; insert output in current buffer asynchronously.
+;; Most of this command was stolen from Emacs shell-command."
+(defun ediff-shell-command (command buffer)
+  (let ((data (match-data)))
+    (unwind-protect
+	(let ((directory default-directory)
+	      proc)
+	  ;; If will kill a process, query first.
+	  (setq proc (get-buffer-process buffer))
+	  (if proc (kill-process proc))
+	  (save-excursion
+	    (set-buffer buffer)
+	    (erase-buffer)
+	    (setq default-directory directory)
+	    (setq proc (start-process "Shell" buffer
+				      shell-file-name "-c" command))
+	    (setq mode-line-process '(":%s"))
+	    (set-process-sentinel proc 'ediff-shell-command-sentinel)
+	    (set-process-filter proc 'ediff-shell-command-filter)
+	    ))
+      (store-match-data data))))
+      
+;; This is shell-command-filter from simple.el in FSF Emacs.
+;; Copied here because XEmacs doesn't have it.
+(defun ediff-shell-command-filter (proc string)
+  ;; Do save-excursion by hand so that we can leave point numerically unchanged
+  ;; despite an insertion immediately after it.
+  (let* ((obuf (current-buffer))
+         (buffer (process-buffer proc))
+         opoint
+         (window (get-buffer-window buffer))
+         (pos (window-start window)))
+    (unwind-protect
+        (progn
+          (set-buffer buffer)
+          (or (= (point) (point-max))
+              (setq opoint (point)))
+          (goto-char (point-max))
+          (insert-before-markers string))
+      ;; insert-before-markers moved this marker: set it back.
+      (set-window-start window pos)
+      ;; Finish our save-excursion.
+      (if opoint
+          (goto-char opoint))
+      (set-buffer obuf))))
+      
+;; like shell-command-sentinel but doesn't print an exit status message
+;; we do this because diff always exits with status 1, if diffs are found
+;; so shell-command-sentinel displays a confusing message to the user
+(defun ediff-shell-command-sentinel (process signal)
+  (if (and (memq (process-status process) '(exit signal))
+           (buffer-name (process-buffer process)))
+      (progn
+        (save-excursion
+          (set-buffer (process-buffer process))
+          (setq mode-line-process nil))
+        (delete-process process))))
+	
+
+;;; Word functions used to refine the current diff	    
+
+(defvar ediff-forward-word-function 'ediff-forward-word
+  "*Function to call to move to the next word.
+Used for splitting difference regions into individual words.")
+
+(defvar ediff-whitespace " \n\t\f"
+  "*Characters constituting white space.
+These characters are ignored when differing regions are split into words.")
+
+;;(defvar ediff-word-1 "a-zA-Z---_`'.?!:"
+(defvar ediff-word-1 "a-zA-Z---_"
+  "*Characters that constitute words of type 1.
+More precisely, [ediff-word-1] is a regexp that matches type 1 words.
+See `ediff-forward-word' for more details.")  
+
+(defvar ediff-word-2 "0-9.,"
+  "*Characters that constitute words of type 2.
+More precisely, [ediff-word-2] is a regexp that matches type 2 words.
+See `ediff-forward-word' for more details.")
+
+(defvar ediff-word-3 "`'?!:;\"{}[]()"
+  "*Characters that constitute words of type 3.
+More precisely, [ediff-word-3] is a regexp that matches type 3 words.
+See `ediff-forward-word' for more details.")
+
+(defvar ediff-word-4
+  (concat "^" ediff-word-1 ediff-word-2 ediff-word-3 ediff-whitespace)
+  "*Characters that constitute words of type 4.
+More precisely, [ediff-word-4] is a regexp that matches type 4 words.
+See `ediff-forward-word' for more details.")  
+
+;; Split region along word boundaries. Each word will be on its own line.
+;; Output to buffer out-buffer.
+(defun ediff-forward-word ()
+  "Move point one word forward.
+There are four types of words, each of which consists entirely of
+characters in `ediff-word-1', `ediff-word-2', `ediff-word-3', or
+`ediff-word-4'.  Words are recognized by passing these in turn as the
+argument to `skip-chars-forward'."
+  (or (> (skip-chars-forward ediff-word-1) 0)
+      (> (skip-chars-forward ediff-word-2) 0)
+      (> (skip-chars-forward ediff-word-3) 0)
+      (> (skip-chars-forward ediff-word-4) 0)
+      ))
+
+(defun ediff-wordify (beg end in-buffer out-buffer &optional control-buf)
+  (let (sv-point string)
+    (save-excursion
+     (set-buffer in-buffer)
+     (setq string (buffer-substring beg end))
+
+     (set-buffer out-buffer)
+     (erase-buffer)
+     (insert string)
+     (goto-char (point-min))
+     (skip-chars-forward ediff-whitespace)
+     (delete-region (point-min) (point))
+     
+     (while (not (eobp))
+       ;; eval incontrol buf to let user create local versions for
+       ;; different invocations
+       (if control-buf
+	   (funcall 
+	    (ediff-eval-in-buffer control-buf ediff-forward-word-function))
+	 (funcall ediff-forward-word-function))
+       (setq sv-point (point))
+       (skip-chars-forward ediff-whitespace)
+       (delete-region sv-point (point))
+       (insert "\n")))))
+       
+;; copy string from BEG END from IN-BUF to OUT-BUF
+(defun ediff-copy-to-buffer (beg end in-buffer out-buffer)
+  (let (string)
+    (save-excursion
+      (set-buffer in-buffer)
+     (setq string (buffer-substring beg end))
+
+     (set-buffer out-buffer)
+     (erase-buffer)
+     (insert string)
+     (goto-char (point-min)))))
+
+
+;; goto word #n starting at current position in buffer `buf'
+;; For ediff, a word is either a string of a-z,A-Z, incl `-' and `_';
+;; or a string of other non-blanks. A blank is a \n\t\f
+;; If `flag' is non-nil, goto the end of the n-th word.
+(defun ediff-goto-word (n buf &optional flag)
+  ;; remember val ediff-forward-word-function has in ctl buf
+  (let ((fwd-word-fun ediff-forward-word-function))
+    (ediff-eval-in-buffer buf
+      (skip-chars-forward ediff-whitespace)
+      (while (> n 1)
+	(funcall fwd-word-fun)
+	(skip-chars-forward ediff-whitespace)
+	(setq n (1- n)))
+      (if (and flag (> n 0))
+	  (funcall fwd-word-fun))
+      (point))))
+
+
+(provide 'ediff-diff)
+
+
+;; ediff-diff.el ends here
diff --git a/lisp/ediff-init.el b/lisp/ediff-init.el
new file mode 100644
index 00000000000..2d0d1b2decc
--- /dev/null
+++ b/lisp/ediff-init.el
@@ -0,0 +1,1189 @@
+;;; ediff-init.el --- Macros, variables and defsubsts used by Ediff
+;;; Copyright (C) 1994 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+(defconst ediff-xemacs-p (string-match "\\(Lucid\\|Xemacs\\)" emacs-version)
+  "Whether it is XEmacs.")
+(defconst ediff-emacs-p (not ediff-xemacs-p)
+  "Whether it is Emacs.")
+
+;;; Macros
+(defmacro ediff-odd-p (arg)
+  (` (eq (logand (, arg) 1) 1)))
+
+(defmacro ediff-buffer-live-p (buf)
+  (` (and (, buf) (get-buffer (, buf)) (buffer-name (get-buffer (, buf))))))
+
+(defmacro ediff-get-buffer (arg)
+  (` (cond ((eq (, arg) 'A) ediff-buffer-A)
+	   ((eq (, arg) 'B) ediff-buffer-B)
+	   ((eq (, arg) 'C) ediff-buffer-C)
+	   )
+  ))
+  
+(defmacro ediff-get-value-according-to-buffer-type (buf-type list)
+  (` (cond ((eq (, buf-type) 'A) (nth 0 (, list)))
+	   ((eq (, buf-type) 'B) (nth 1 (, list)))
+	   ((eq (, buf-type) 'C) (nth 2 (, list))))))
+	   
+(defmacro ediff-char-to-buftype (arg)
+  (` (cond ((memq (, arg) '(?a ?A)) 'A)
+	   ((memq (, arg) '(?b ?B)) 'B)
+	   ((memq (, arg) '(?c ?C)) 'C)
+	   )
+  ))
+  
+(defmacro ediff-get-difference (n buf-type)
+  (` (aref
+      (symbol-value
+       (intern (format "ediff-difference-vector-%S" (, buf-type)))) (, n))))
+  
+;; tell if it has been previously determined that the region has
+;; no diffs other than the white space and newlines
+;; The argument, N, is the diff region number used by Ediff to index the
+;; diff vector. It is 1 less than the number seen by the user.
+;;
+;; A difference vector has the form:
+;; [diff diff diff ...]
+;; where each diff has the form:
+;; [overlay fine-diff-vector no-fine-diffs-flag]
+;; fine-diff-vector is a vector [fine-diff fine-diff fine-diff ...]
+(defmacro ediff-no-fine-diffs-p (n)
+  (` (aref (ediff-get-difference (, n) 'A) 2)))
+  
+(defmacro ediff-get-diff-overlay-from-diff-record (diff-rec)
+  (` (aref (, diff-rec) 0)))
+  
+(defmacro ediff-get-diff-overlay (n buf-type)  
+  (` (ediff-get-diff-overlay-from-diff-record
+      (ediff-get-difference (, n) (, buf-type)))))
+
+(defmacro ediff-get-fine-diff-vector-from-diff-record (diff-rec)
+  (` (aref (, diff-rec) 1)))
+      
+(defmacro ediff-set-fine-diff-vector (n buf-type fine-vec)
+  (` (aset (ediff-get-difference (, n) (, buf-type)) 1 (, fine-vec))))
+  
+(defmacro ediff-get-state-of-diff (n buf-type)
+  (` (if (ediff-buffer-live-p ediff-buffer-C)
+	 (aref (ediff-get-difference (, n) (, buf-type)) 3))))
+(defmacro ediff-set-state-of-diff (n buf-type val)
+  (` (aset (ediff-get-difference (, n) (, buf-type)) 3 (, val))))
+(defmacro ediff-get-state-of-merge (n)
+  (` (if (ediff-buffer-live-p ediff-buffer-C)
+	 (aref (ediff-get-difference (, n) 'C) 4))))
+(defmacro ediff-set-state-of-merge (n val)
+  (` (aset (ediff-get-difference (, n) 'C) 4 (, val))))
+
+;; if flag is t, puts a mark on diff region saying that 
+;; the differences are in white space only. If flag is nil,
+;; the region is marked as essential (i.e., differences are
+;; not just in the white space and newlines.)
+(defmacro ediff-mark-diff-as-space-only (n flag)
+  (` (aset (ediff-get-difference (, n) 'A) 2 (, flag))))
+  
+(defmacro ediff-get-fine-diff-vector (n buf-type)
+  (` (ediff-get-fine-diff-vector-from-diff-record
+      (ediff-get-difference (, n) (, buf-type)))))
+  
+  
+;; Defines SYMBOL as an advertised local variable.  
+;; Performs a defvar, then executes `make-variable-buffer-local' on
+;; the variable.  Also sets the `permanent-local' property,
+;; so that `kill-all-local-variables' (called by major-mode setting
+;; commands) won't destroy Ediff control variables.
+;; 
+;; Plagiarised from `emerge-defvar-local' for XEmacs.
+(defmacro ediff-defvar-local (var value doc) 
+  (` (progn
+       (defvar (, var) (, value) (, doc))
+       (make-variable-buffer-local '(, var))
+       (put '(, var) 'permanent-local t))))
+    
+;; Macro to switch to BUFFER, evaluate FORMS, returns to original buffer.
+;; Differs from `save-excursion' in that it doesn't save the point and mark.
+;; This is essentially `emerge-eval-in-buffer' with the test for live buffers."
+(defmacro ediff-eval-in-buffer (buffer &rest forms)
+  (` (let ((StartBuffer (current-buffer)))
+       (if (ediff-buffer-live-p (, buffer))
+	   (unwind-protect
+	       (progn
+		 (set-buffer (, buffer))
+		 (,@ forms))
+	     (set-buffer StartBuffer))
+	 (or (eq this-command 'ediff-quit)
+	     (error
+	      "You've killed an essential Ediff buffer---Please quit Ediff"))
+	 ))))
+	 
+
+(defmacro ediff-multiframe-setup-p ()
+  (` (and window-system ediff-multiframe)))
+			 
+(defmacro ediff-narrow-control-frame-p ()
+  (` (and (ediff-multiframe-setup-p)
+	  (equal ediff-help-message ediff-brief-message-string))))
+	  
+(defmacro ediff-3way-comparison-job ()
+  (` (memq
+      ediff-job-name
+      '(ediff-files3 ediff-buffers3))))
+(ediff-defvar-local ediff-3way-comparison-job nil "")
+      
+(defmacro ediff-merge-job ()
+  (` (memq
+      ediff-job-name
+      '(ediff-merge-files
+	ediff-merge-buffers
+	ediff-merge-files-with-ancestor
+	ediff-merge-buffers-with-ancestor
+	ediff-merge-revisions
+	ediff-merge-revisions-with-ancestor))))
+(ediff-defvar-local ediff-merge-job nil "")
+
+(defmacro ediff-merge-with-ancestor-job ()
+  (` (memq
+      ediff-job-name
+      '(ediff-merge-files-with-ancestor
+	ediff-merge-buffers-with-ancestor
+	ediff-merge-revisions-with-ancestor))))
+(ediff-defvar-local ediff-merge-with-ancestor-job nil "")
+
+(defmacro ediff-3way-job ()
+  (` (or ediff-3way-comparison-job ediff-merge-job)))
+(ediff-defvar-local ediff-3way-job nil "")
+
+;; A diff3 job is like a 3way job, but ediff-merge doesn't require the use
+;; of diff3.
+(defmacro ediff-diff3-job ()
+  (` (or ediff-3way-comparison-job
+	 ediff-merge-with-ancestor-job)))
+(ediff-defvar-local ediff-diff3-job nil "")
+	 
+(defmacro ediff-word-mode-job ()
+  (` (memq
+      ediff-job-name
+      '(ediff-windows ediff-small-regions ediff-large-regions))))
+(ediff-defvar-local ediff-word-mode-job nil "")
+
+
+;; Hook variables
+
+(defvar ediff-before-setup-windows-hooks nil
+  "*Hooks to run before Ediff sets its own window config. 
+This can be used to save the previous window config, which can be restored
+on ediff-quit or ediff-suspend.") 
+(defvar ediff-after-setup-windows-hooks nil
+  "*Hooks to run after Ediff sets its own window config. 
+This can be used to set up control window or icon in a desired place.")
+(defvar ediff-before-setup-control-frame-hooks nil
+  "*Hooks run before setting up the frame to display Ediff Control Panel.
+Can be used to change control frame parameters to position it where it
+is desirable.")
+(defvar ediff-after-setup-control-frame-hooks nil
+  "*Hooks run after setting up the frame to display Ediff Control Panel.
+Can be used to move the frame where it is desired.")
+(defvar ediff-startup-hooks nil
+  "*Hooks to run in the control buffer after Ediff has been set up.")
+(defvar ediff-select-hooks nil
+  "*Hooks to run after a difference has been selected.")
+(defvar ediff-unselect-hooks nil
+  "*Hooks to run after a difference has been unselected.")
+(defvar ediff-prepare-buffer-hooks  nil
+  "*Hooks called after buffers A, B, and C are set up.")
+(defvar ediff-load-hooks nil
+  "*Hook run after Ediff is loaded.  Can be used to change defaults.")
+  
+(defvar ediff-mode-hooks nil
+  "*Hook run just after ediff-mode is set up in the control buffer. 
+This is done before any windows or frames are created. One can use it to
+set local variables that determine how the display looks like.")
+(defvar ediff-keymap-setup-hooks nil
+  "*Hook run just after the default bindings in Ediff keymap are set up.")
+  
+(defvar ediff-display-help-hooks nil
+  "*Hooks run after preparing the help message.")
+
+(defvar ediff-suspend-hooks (list 'ediff-default-suspend-hook)
+  "*Hooks to run in the Ediff control buffer when Ediff is suspended.")
+(defvar ediff-quit-hooks (list 'ediff-cleanup-mess)
+  "*Hooks to run in the Ediff control buffer after finishing Ediff.") 
+
+;; There will be deleted in due time
+(make-variable-buffer-local 'local-write-file-hooks)
+(make-variable-buffer-local 'before-change-function)
+
+
+;; Help messages
+
+(defconst ediff-long-help-message-head
+  "   Moving around     |     Toggling features     |       Manipulations
+=====================|===========================|============================="
+  "The head of the full help message.")
+(defconst ediff-long-help-message-tail
+  "=====================|===========================|=============================
+    i -status info   |     ? -help off           |  G -send bug report   
+-------------------------------------------------------------------------------
+X,Y (x,y)  on the left are meta-symbols for the keys  A,B,C (a,b,c).
+X,Y on the right are meta-symbols for buffers A,B,C.
+A,B,C on the right denote the working buffers A,B,C, respectively."
+  "The tail of the full-help message.")
+
+(defconst ediff-long-help-message-compare3
+  "
+p,DEL -previous diff |     | -vert/horiz split   | xy -copy buf X's region to Y
+n,SPC -next diff     |     h -hiliting           | rx -restore buf X's old diff
+    j -jump to diff  |     @ -auto-refinement    |  * -refine current region
+   gx -goto X's point|                           |  ! -update diff regions
+  C-l -recenter      |    ## -ignore whitespace  |
+  v/V -scroll up/dn  | #f/#h -focus/hide regions | wx -save buf X
+  </> -scroll lt/rt  |     X -read-only in buf X | wd -save diff output
+  z/q -suspend/quit  |     m -wide display       |  ~ -rotate buffers
+"
+  "Normally, not a user option. See `ediff-help-message' for details.")
+  
+(defconst ediff-long-help-message-compare2
+  "
+p,DEL -previous diff |     | -vert/horiz split   |a/b -copy A/B's region to B/A
+n,SPC -next diff     |     h -hiliting           | rx -restore buf X's old diff
+    j -jump to diff  |     @ -auto-refinement    |  * -refine current region
+   gx -goto X's point|                           |  ! -update diff regions
+  C-l -recenter      |    ## -ignore whitespace  |
+  v/V -scroll up/dn  | #f/#h -focus/hide regions | wx -save buf X
+  </> -scroll lt/rt  |     X -read-only in buf X | wd -save diff output
+  z/q -suspend/quit  |     m -wide display       |  ~ -swap buffers
+"
+  "Normally, not a user option. See `ediff-help-message' for details.")
+  
+(defconst ediff-long-help-message-word-mode
+  "
+p,DEL -previous diff |     | -vert/horiz split   | xy -copy buf X's region to Y
+n,SPC -next diff     |     h -hiliting           | rx -restore buf X's old diff
+    j -jump to diff  |                           |                   
+   gx -goto X's point|     % -narrow/widen buffs |  ! -recompute diffs
+  C-l -recenter      |                           |
+  v/V -scroll up/dn  | #f/#h -focus/hide regions | wx -save buf X
+  </> -scroll lt/rt  |     X -read-only in buf X | wd -save diff output
+  z/q -suspend/quit  |     m -wide display       |  ~ -swap buffers
+"
+  "Normally, not a user option. See `ediff-help-message' for details.")
+  
+(defconst ediff-long-help-message-merge
+  "
+p,DEL -previous diff |     | -vert/horiz split   |  x -copy buf X's region to C
+n,SPC -next diff     |     h -hiliting           |  r -restore buf C's old diff
+    j -jump to diff  |     @ -auto-refinement    |  * -refine current region
+   gx -goto X's point|    ## -ignore whitespace  |  ! -update diff regions
+  C-l -recenter      | #f/#h -focus/hide regions |  + -combine diff regions
+  v/V -scroll up/dn  |     X -read-only in buf X | wx -save buf X
+  </> -scroll lt/rt  |     m -wide display       | wd -save diff output
+  z/q -suspend/quit  |     s -shrink window C    |  ~ -swap buffers
+                     |     $ -show clashes only  |  & -merge w/new default
+"
+  "Normally, not a user option. See `ediff-help-message' for details.")
+
+;; The actual long help message.
+(ediff-defvar-local ediff-long-help-message ""
+  "Normally, not a user option. See `ediff-help-message' for details.")
+  
+(defconst ediff-brief-message-string
+  "  ? - help  "
+  "Contents of the brief help message.")
+;; The actual brief help message
+(ediff-defvar-local ediff-brief-help-message ""
+  "Normally, not a user option. See `ediff-help-message' for details.")
+  
+(ediff-defvar-local ediff-brief-help-message-custom nil
+  "The brief help message that the user can customize.
+If the user sets this to a parameter-less function, Ediff will use it to
+produce the brief help message. This function must return a string.")
+(ediff-defvar-local ediff-long-help-message-custom nil
+  "The long help message that the user can customize.
+See `ediff-brief-help-message-custom' for more.")
+
+(defvar ediff-prefer-long-help-message nil
+  "*If t, Ediff starts with a long help message. Short help msg otherwise.")
+
+;; The actual help message.
+(ediff-defvar-local ediff-help-message ""
+  "The actual help message.
+Normally, the user shouldn't touch this. However, if you want Ediff to
+start up with different help messages for different jobs, you can change
+the value of this variable and the variables `ediff-help-message-*' in
+`ediff-startup-hooks'.") 
+ 
+;; Selective browsing
+
+(ediff-defvar-local ediff-skip-diff-region-function 'ediff-show-all-diffs
+  "Function that determines the next/previous diff region to show.
+Should return t for regions to be ignored and nil otherwise.
+This function gets a region number as an argument. The region number
+is the one used internally by Ediff. It is 1 less than the number seen
+by the user.")
+
+;; Regexp that determines buf A regions to focus on when skipping to diff
+(ediff-defvar-local ediff-regexp-focus-A "" "")
+;; Regexp that determines buf B regions to focus on when skipping to diff
+(ediff-defvar-local ediff-regexp-focus-B "" "")
+;; Regexp that determines buf C regions to focus on when skipping to diff
+(ediff-defvar-local ediff-regexp-focus-C "" "")
+;; connective that determines whether to focus regions that match both or
+;; one of the regexps
+(ediff-defvar-local ediff-focus-regexp-connective 'and "")
+  
+;; Regexp that determines buf A regions to ignore when skipping to diff
+(ediff-defvar-local ediff-regexp-hide-A "" "")
+;; Regexp that determines buf B regions to ignore when skipping to diff
+(ediff-defvar-local ediff-regexp-hide-B "" "")
+;; Regexp that determines buf C regions to ignore when skipping to diff
+(ediff-defvar-local ediff-regexp-hide-C "" "")
+;; connective that determines whether to hide regions that match both or
+;; one of the regexps
+(ediff-defvar-local ediff-hide-regexp-connective 'and "")
+  
+  
+(defvar ediff-ange-ftp-ftp-name (if ediff-xemacs-p
+				    'ange-ftp-ftp-path
+				  'ange-ftp-ftp-name)
+  "Function ange-ftp uses to find out if file is remote.")
+  
+
+;; Copying difference regions between buffers.    
+(ediff-defvar-local ediff-killed-diffs-alist nil
+  "A list of killed diffs. 
+A diff is saved here if it is replaced by a diff
+from another buffer.  This alist has the form:
+\((num (buff-object . diff) (buff-object . diff) (buff-object . diff)) ...),
+where some buffer-objects may be missing.")
+
+
+;; Highlighting
+(defvar ediff-before-flag-bol   "->>\n"
+  "*Flag placed above the highlighted block of differences. 
+Must end with newline.")
+(defvar ediff-after-flag-eol    "<<-\n"
+  "*Flag placed below the highlighted block of differences.
+Must end with newline.")
+
+(defvar ediff-before-flag-mol   "->>"
+  "*Like ediff-before-flag, used when a difference starts in mid-line.")
+(defvar ediff-after-flag-mol    "<<-"
+  "*Like ediff-after-flag, used when a difference starts in mid-line.")
+
+(ediff-defvar-local ediff-before-flag-A nil
+  "This is the actual ASCII before-flag in effect in buffer A.
+It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
+on whether the selected difference region starts in the middle of a line 
+or at the beginning of a line.")
+(ediff-defvar-local ediff-after-flag-A nil
+  "This is the actual ASCII after-flag in effect in buffer A.
+It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
+on whether the selected difference region starts in the middle of a line 
+or at the beginning of a line.")
+
+(ediff-defvar-local ediff-before-flag-B nil
+  "This is the actual ASCII before-flag in effect in buffer B.
+It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
+on whether the selected difference region starts in the middle of a line 
+or at the beginning of a line.")
+(ediff-defvar-local ediff-after-flag-B nil
+  "This is the actual ASCII after-flag in effect in buffer B.
+It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
+on whether the selected difference region starts in the middle of a line 
+or at the beginning of a line.")
+
+(ediff-defvar-local ediff-before-flag-C nil
+  "This is the actual ASCII before-flag in effect in buffer C.
+It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
+on whether the selected difference region starts in the middle of a line 
+or at the beginning of a line.")
+(ediff-defvar-local ediff-after-flag-C nil
+  "This is the actual ASCII after-flag in effect in buffer C.
+It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
+on whether the selected difference region starts in the middle of a line 
+or at the beginning of a line.")
+
+  
+(ediff-defvar-local ediff-use-faces t 
+  "If t, differences are highlighted using faces on a window system.
+If nil, they are highlighted using ASCII flags, ediff-before-flag
+and ediff-after-flag.  On a non-window system, differences are always
+highlighted using ASCII flags.
+This variable can be set either in .emacs or toggled interactively.
+Use `setq-default' if setting it in .emacs")
+
+
+;; this indicates that diff regions are word-size, so fine diffs are
+;; permanently nixed; used in ediff-windows and ediff-small-regions
+(ediff-defvar-local ediff-word-mode nil "")
+;; Name of the job (ediff-files, ediff-windows, etc.
+(ediff-defvar-local ediff-job-name nil "")
+
+;; Narrowing and ediff-region/windows support
+;; This is a list (overlay-A overlay-B overlay-C)
+;; If set, Ediff compares only those parts of buffers A/B/C that lie within
+;; the bounds of these overlays.
+(ediff-defvar-local ediff-narrow-bounds nil "")
+
+;; List (overlay-A overlay-B overlay-C), where each overlay spans the
+;; entire corresponding buffer.
+(ediff-defvar-local ediff-wide-bounds nil "")
+
+;; Current visibility boundaries in buffers A, B, and C.
+;; This is also a list of overlays. When the user toggles narrow/widen,
+;; this list changes from ediff-wide-bounds to ediff-narrow-bounds.
+;; and back.
+(ediff-defvar-local ediff-visible-bounds nil "")
+
+(ediff-defvar-local ediff-start-narrowed t
+  "Non-nil means start narrowed, if doing ediff-windows, ediff-small-regions,
+or ediff-large-regions.")
+(ediff-defvar-local ediff-quit-widened t
+  "*Non-nil means: when finished, Ediff widens buffers A/B.
+Actually, Ediff restores the scope of visibility that existed at startup.")
+
+(ediff-defvar-local ediff-highlight-all-diffs t
+  "If nil, only the selected differences are highlighted.
+This variable can be set either in .emacs or toggled interactively, using
+ediff-toggle-hilit. Use `setq-default' to set it.") 
+
+;; A var local to each control panel buffer.  Indicates highlighting style
+;; in effect for this buffer: `face', `ascii', nil -- temporarily
+;; unhighlighted, `off' -- turned off \(on a dumb terminal only\).
+(ediff-defvar-local ediff-highlighting-style nil "")
+
+
+;; Variables that control each Ediff session.  They are local to the
+;; control buffer. 
+
+;; Mode variables
+;; The buffer in which the A variant is stored.
+(ediff-defvar-local ediff-buffer-A nil "")
+;; The buffer in which the B variant is stored.
+(ediff-defvar-local ediff-buffer-B nil "")
+;; The buffer in which the C variant is stored.
+(ediff-defvar-local ediff-buffer-C nil "")
+;; Ancestor buffer
+(ediff-defvar-local ediff-ancestor-buffer nil "")
+;; The control buffer of ediff.
+(ediff-defvar-local ediff-control-buffer nil "")
+
+  
+;; The suffix of the control buffer name.
+(ediff-defvar-local ediff-control-buffer-suffix nil "")
+;; Same as ediff-control-buffer-suffix, but without <,>. 
+;; It's a number rather than string.
+(ediff-defvar-local ediff-control-buffer-number nil "")
+
+
+;; There three are to be deleted in due time
+;; Working values of ediff-saved-variables for buffer A.
+(ediff-defvar-local ediff-buffer-A-values nil "")
+;; working values of ediff-saved-variables for buffer B.
+(ediff-defvar-local ediff-buffer-B-values nil "")
+;; working values of ediff-saved-variables for buffer C.
+(ediff-defvar-local ediff-buffer-C-values nil "")
+
+;; The original values of ediff-protected-variables for buffer A
+(ediff-defvar-local ediff-buffer-A-values-orig nil "")
+;; The original values of ediff-protected-variables for buffer B
+(ediff-defvar-local ediff-buffer-B-values-orig nil "")
+;; The original values of ediff-protected-variables for buffer C
+(ediff-defvar-local ediff-buffer-C-values-orig nil "")
+;; Buffer-local variables to be saved then restored during Ediff sessions
+(defconst ediff-protected-variables '(buffer-read-only 
+				      mode-line-format))
+
+;; These three vars are to be deleted when emacs gets before/after strings
+;; Remember ediff-saved-variables for ediff-buffer-A as they were at setup.
+(ediff-defvar-local ediff-buffer-A-values-setup nil "")
+;; Remembers ediff-saved-variables for ediff-buffer-B as they were at setup.
+(ediff-defvar-local ediff-buffer-B-values-setup nil "")
+;; Remembers ediff-saved-variables for ediff-buffer-C as they were at setup.
+(ediff-defvar-local ediff-buffer-C-values-setup nil "")
+  
+;; Vector of differences between the variants.  Each difference is
+;; represented by a vector of two overlays plus a vector of fine diffs,
+;; plus a no-fine-diffs flag.  The first overlay spans the
+;; difference region in the A buffer and the second overlays the diff in
+;; the B buffer. If a difference section is empty, the corresponding
+;; overlay's endpoints coincide.
+;;
+;; The precise form of a difference vector for one buffer is:
+;; [diff diff diff ...]
+;; where each diff has the form:
+;; [diff-overlay fine-diff-vector no-fine-diffs-flag state-of-difference
+;; state-of-merge]
+;; fine-diff-vector is a vector [fine-diff-overlay fine-diff-overlay ...]
+;; no-fine-diffs-flag says if there are fine differences.
+;; state-of-difference is A, B, C, or nil, indicating which buffer is
+;; different from the other two (used only in 3-way jobs.
+;; state-of-merge is default-A, default-B, prefer-A, or prefer-B. It
+;; indicates the way a diff region was created in buffer C.
+(ediff-defvar-local ediff-difference-vector-A nil "")
+(ediff-defvar-local ediff-difference-vector-B nil "")
+(ediff-defvar-local ediff-difference-vector-C nil "")
+
+;; The difference that is currently selected.
+(ediff-defvar-local ediff-current-difference -1 "")
+;; Number of differences found.
+(ediff-defvar-local ediff-number-of-differences nil "")
+  
+;; Buffer containing the output of diff, which is used by Ediff to step
+;; through files.
+(ediff-defvar-local ediff-diff-buffer nil "")
+;; Like ediff-diff-buffer, but contains context diff. It is not used by
+;; Ediff, but it is saved in a file, if user requests so.
+(ediff-defvar-local ediff-custom-diff-buffer nil "")
+;; Buffer used for diff-style fine differences between regions.
+(ediff-defvar-local ediff-fine-diff-buffer nil "")
+;; Temporary buffer used for computing fine differences.
+(defconst ediff-tmp-buffer " *ediff-tmp*" "")
+;; Buffer used for messages
+(defconst ediff-msg-buffer " *ediff-message*" "")
+;; Buffer containing the output of diff when diff returns errors.
+(ediff-defvar-local ediff-error-buffer nil "")
+;; Buffer to display debug info
+(ediff-defvar-local ediff-debug-buffer "*ediff-debug*" "")
+
+;; to be deleted in due time
+;; List of ediff control panels associated with each buffer A/B.
+(ediff-defvar-local ediff-this-buffer-control-sessions  nil "")
+
+;; to be deleted in due time
+;; List of difference overlays disturbed by working with the current diff.
+(defvar ediff-disturbed-overlays nil "")
+  
+;; Priority of non-selected overlays.
+(defvar ediff-shadow-overlay-priority  100 "")
+
+
+(if ediff-xemacs-p
+    (progn
+      (fset 'ediff-read-event (symbol-function 'next-command-event))
+      (fset 'ediff-overlayp (symbol-function 'extentp))
+      (fset 'ediff-make-overlay (symbol-function 'make-extent))
+      (fset 'ediff-delete-overlay (symbol-function 'delete-extent))
+      (fset 'ediff-overlay-buffer (symbol-function 'extent-buffer))
+      (fset 'ediff-overlay-p (symbol-function 'extentp))
+      (fset 'ediff-overlay-get (symbol-function 'extent-property)))
+  (fset 'ediff-read-event (symbol-function 'read-event))
+  (fset 'ediff-overlayp (symbol-function 'overlayp))
+  (fset 'ediff-make-overlay (symbol-function 'make-overlay))
+  (fset 'ediff-delete-overlay (symbol-function 'delete-overlay))
+  (fset 'ediff-overlay-buffer (symbol-function 'overlay-buffer))
+  (fset 'ediff-overlay-p (symbol-function 'overlayp))
+  (fset 'ediff-overlay-get (symbol-function 'overlay-get)))
+  
+;; A fix for NeXT Step
+;; Should probably be eliminated in later versions.
+(if (and window-system (eq window-system 'ns))
+    (progn
+      (fset 'x-display-color-p (symbol-function 'ns-display-color-p))
+      (fset 'x-color-defined-p (symbol-function 'ns-color-defined-p))
+      (fset 'x-display-pixel-height (symbol-function 'ns-display-pixel-height))
+      (fset 'x-display-pixel-width (symbol-function 'ns-display-pixel-width))
+      ))
+  
+(if ediff-xemacs-p
+    (progn
+      (fset 'ediff-make-frame (symbol-function 'make-screen))
+      ;;(fset 'ediff-make-frame-invisible
+      ;;    (symbol-function 'make-screen-invisible))
+      (fset 'ediff-raise-frame (symbol-function 'raise-screen))
+      (fset 'ediff-iconify-frame (symbol-function 'iconify-screen))
+      (fset 'ediff-delete-frame (symbol-function 'delete-screen))
+      (fset 'ediff-frame-visible-p (symbol-function 'screen-visible-p))
+      (fset 'ediff-select-frame (symbol-function 'select-screen))
+      (fset 'ediff-selected-frame (symbol-function 'selected-screen))
+      ;;(fset 'ediff-frame-selected-window
+      ;;    (symbol-function 'screen-selected-window))
+      (fset 'ediff-frame-parameters (symbol-function 'screen-parameters))
+      ;;(fset 'ediff-frame-pixel-width (symbol-function 'screen-pixel-width))
+      (fset 'ediff-frame-width (symbol-function 'screen-width))
+      (fset 'ediff-modify-frame-parameters
+	    (symbol-function 'modify-screen-parameters))
+      (fset 'ediff-frame-live-p (symbol-function 'screen-live-p))
+      (fset 'ediff-window-frame (symbol-function 'window-screen))
+      (if window-system
+	  (progn
+	    (fset 'ediff-display-color-p (symbol-function 'x-color-display-p))
+	    (fset 'ediff-valid-color-p (symbol-function 'x-valid-color-name-p))
+	    (fset 'ediff-get-face (symbol-function 'get-face)))))
+  (if window-system
+      (progn
+	(fset 'ediff-make-frame (symbol-function 'make-frame))
+	;;(fset 'ediff-make-frame-invisible
+	;;      (symbol-function 'make-frame-invisible))
+	(fset 'ediff-raise-frame (symbol-function 'raise-frame))
+	(fset 'ediff-iconify-frame (symbol-function 'iconify-frame))
+	(fset 'ediff-delete-frame (symbol-function 'delete-frame))
+	(fset 'ediff-frame-visible-p (symbol-function 'frame-visible-p))
+	(fset 'ediff-window-frame (symbol-function 'window-frame))
+	(fset 'ediff-select-frame (symbol-function 'select-frame))
+	(fset 'ediff-selected-frame (symbol-function 'selected-frame))
+	;;(fset 'ediff-frame-selected-window
+	;;	(symbol-function 'frame-selected-window))
+	(fset 'ediff-frame-parameters (symbol-function 'frame-parameters))
+	;;(fset 'ediff-frame-pixel-width (symbol-function 'frame-pixel-width))
+	(fset 'ediff-frame-width (symbol-function 'frame-width))
+	(fset 'ediff-modify-frame-parameters
+	      (symbol-function 'modify-frame-parameters))
+	(fset 'ediff-frame-live-p (symbol-function 'frame-live-p))
+	))
+  
+  (if window-system
+      (progn
+	(fset 'ediff-display-color-p (symbol-function 'x-display-color-p))
+	;; Temporary fix for OS/2 users
+	;; pm-win.el in PM-Emacs should be fixed.
+	(if (eq window-system 'pm)
+	    (fset 'ediff-valid-color-p 
+		  (function (lambda (color) (assoc color pm-color-alist))))
+	  (fset 'ediff-valid-color-p (symbol-function 'x-color-defined-p)))
+      
+	(fset 'ediff-get-face (symbol-function 'internal-get-face))))
+  )
+  
+;; not a window system
+(if (not window-system)
+    (progn
+      (fset 'ediff-window-frame (function (lambda (wind) (if wind 1 nil)) ))
+      (fset 'ediff-selected-frame 'selected-window)
+      (fset 'ediff-frame-width 'window-width)
+      (fset 'ediff-make-current-diff-overlay (function (lambda (type) nil)))))
+
+(if (not window-system)
+    ()
+  (defun ediff-set-face (ground face color)
+    "Sets face foreground/background."
+    (if (ediff-valid-color-p color)
+	(if (eq ground 'foreground)
+	    (set-face-foreground face color)
+	  (set-face-background face color))
+      (cond ((memq face
+		   '(ediff-current-diff-face-A
+		     ediff-current-diff-face-B
+		     ediff-current-diff-face-C))
+	     (copy-face 'highlight face))
+	    ((memq face
+		   '(ediff-fine-diff-face-A
+		     ediff-fine-diff-face-B
+		     ediff-fine-diff-face-C
+;;		     ediff-combined-diff-face
+		     ))
+	     (copy-face 'secondary-selection face)
+	     (set-face-underline-p face t))
+	    ((memq face
+		   '(ediff-even-diff-face-A ediff-odd-diff-face-A 
+		     ediff-even-diff-face-B ediff-odd-diff-face-B
+		     ediff-even-diff-face-C ediff-odd-diff-face-C))
+	     (copy-face 'secondary-selection face)))))
+      
+  (defvar ediff-current-diff-face-A
+    (progn
+      (make-face 'ediff-current-diff-face-A)
+      (or (face-differs-from-default-p 'ediff-current-diff-face-A)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-current-diff-face-A "firebrick")
+		 (ediff-set-face
+		  'background 'ediff-current-diff-face-A "pale green"))
+		(t
+		 (if ediff-xemacs-p
+		     (copy-face 'modeline 'ediff-current-diff-face-A)
+		   (copy-face 'highlight 'ediff-current-diff-face-A))
+		 )))
+      'ediff-current-diff-face-A)
+    "Face for highlighting the selected difference in buffer A.")
+
+  (defvar ediff-current-diff-face-B
+    (progn
+      (make-face 'ediff-current-diff-face-B)
+      (or (face-differs-from-default-p 'ediff-current-diff-face-B)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-current-diff-face-B "DarkOrchid")
+		 (ediff-set-face
+		  'background 'ediff-current-diff-face-B "Yellow"))
+		(t 
+		 (if ediff-xemacs-p
+		     (copy-face 'modeline 'ediff-current-diff-face-B)
+		   (copy-face 'highlight 'ediff-current-diff-face-B))
+		 )))
+      'ediff-current-diff-face-B)
+    "Face for highlighting the selected difference in buffer B.")
+    
+
+  (defvar ediff-current-diff-face-C
+    (progn
+      (make-face 'ediff-current-diff-face-C)
+      (or (face-differs-from-default-p 'ediff-current-diff-face-C)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-current-diff-face-C "Navy")
+		 (ediff-set-face
+		  'background 'ediff-current-diff-face-C "Pink"))
+		(t 
+		 (if ediff-xemacs-p
+		     (copy-face 'modeline 'ediff-current-diff-face-C)
+		   (copy-face 'highlight 'ediff-current-diff-face-C))
+		 )))
+      'ediff-current-diff-face-C)
+    "Face for highlighting the selected difference in buffer C.")
+
+  (defvar ediff-fine-diff-face-A
+    (progn
+      (make-face 'ediff-fine-diff-face-A)
+      (or (face-differs-from-default-p 'ediff-fine-diff-face-A)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face 'foreground 'ediff-fine-diff-face-A
+				 "Navy")
+		 (ediff-set-face 'background 'ediff-fine-diff-face-A
+				 "sky blue"))
+		(t (set-face-underline-p 'ediff-fine-diff-face-A t))))
+      'ediff-fine-diff-face-A)
+    "Face for highlighting the refinement of the selected diff in buffer A.")
+
+  (defvar ediff-fine-diff-face-B
+    (progn
+      (make-face 'ediff-fine-diff-face-B)
+      (or (face-differs-from-default-p 'ediff-fine-diff-face-B)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face 'foreground 'ediff-fine-diff-face-B "Black")
+		 (ediff-set-face 'background 'ediff-fine-diff-face-B "cyan"))
+		(t (set-face-underline-p 'ediff-fine-diff-face-B t))))
+      'ediff-fine-diff-face-B)
+    "Face for highlighting the refinement of the selected diff in buffer B.")
+    
+  (defvar ediff-fine-diff-face-C
+    (progn
+      (make-face 'ediff-fine-diff-face-C)
+      (or (face-differs-from-default-p 'ediff-fine-diff-face-C)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face 'foreground 'ediff-fine-diff-face-C "black")
+		 (ediff-set-face
+		  'background 'ediff-fine-diff-face-C "Turquoise"))
+		(t (set-face-underline-p 'ediff-fine-diff-face-C t))))
+      'ediff-fine-diff-face-C)
+    "Face for highlighting the refinement of the selected diff in buffer C.")
+    
+;;  (defvar ediff-combined-diff-face
+;;    (progn
+;;      (make-face 'ediff-combined-diff-face)
+;;      (or (face-differs-from-default-p 'ediff-combined-diff-face)
+;;	  (cond ((ediff-display-color-p)
+;;		 (ediff-set-face 'foreground 'ediff-combined-diff-face "black")
+;;		 (ediff-set-face
+;;		  'background 'ediff-combined-diff-face "Plum"))
+;;		(t (set-face-underline-p 'ediff-combined-diff-face t))))
+;;      'ediff-combined-diff-face)
+;;    "Face for highlighting combined selected diff regions in buffer C.")
+      
+  (defvar ediff-even-diff-face-A
+    (progn
+      (make-face 'ediff-even-diff-face-A)
+      (or (face-differs-from-default-p 'ediff-even-diff-face-A)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-even-diff-face-A "black")
+		 (ediff-set-face
+		  'background 'ediff-even-diff-face-A "light grey"))
+		(t 
+		 (copy-face 'italic 'ediff-even-diff-face-A))))
+      'ediff-even-diff-face-A)
+    "Face used to highlight even-numbered differences in buffer A.")
+      
+  (defvar ediff-even-diff-face-B
+    (progn
+      (make-face 'ediff-even-diff-face-B)
+      (or (face-differs-from-default-p 'ediff-even-diff-face-B)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-even-diff-face-B "White")
+		 (ediff-set-face
+		  'background 'ediff-even-diff-face-B "Gray"))
+		(t 
+		 (copy-face 'italic 'ediff-even-diff-face-B))))
+      'ediff-even-diff-face-B)
+    "Face used to highlight even-numbered differences in buffer B.")
+    
+  (defvar ediff-even-diff-face-C
+    (progn
+      (make-face 'ediff-even-diff-face-C)
+      (copy-face 'ediff-even-diff-face-A 'ediff-even-diff-face-C)
+      'ediff-even-diff-face-C)
+    "Face used to highlight even-numbered differences in buffer C.")
+  
+  (defvar ediff-odd-diff-face-A
+    (progn
+      (make-face 'ediff-odd-diff-face-A)
+      (or (face-differs-from-default-p 'ediff-odd-diff-face-A)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-odd-diff-face-A "White")
+		 (ediff-set-face
+		  'background 'ediff-odd-diff-face-A "Gray"))
+		(t 
+		 (copy-face 'italic 'ediff-odd-diff-face-A))))
+      'ediff-odd-diff-face-A)
+    "Face used to highlight odd-numbered differences in buffer A.")
+      
+  (defvar ediff-odd-diff-face-B
+    (progn
+      (make-face 'ediff-odd-diff-face-B)
+      (or (face-differs-from-default-p 'ediff-odd-diff-face-B)
+	  (cond ((ediff-display-color-p)
+		 (ediff-set-face
+		  'foreground 'ediff-odd-diff-face-B "Black")
+		 (ediff-set-face
+		  'background 'ediff-odd-diff-face-B "light grey"))
+		(t 
+		 (copy-face 'italic 'ediff-odd-diff-face-B))))
+      'ediff-odd-diff-face-B)
+    "Face used to highlight odd-numbered differences in buffer B.")
+    
+  (defvar ediff-odd-diff-face-C
+    (progn
+      (make-face 'ediff-odd-diff-face-C)
+      (copy-face 'ediff-odd-diff-face-A 'ediff-odd-diff-face-C)
+      'ediff-odd-diff-face-C)
+    "Face used to highlight odd-numbered differences in buffer C.")
+
+  ;; Create *-var faces. These are the actual faces used to highlight
+  ;; odd-numbered difference regions.
+  ;; They are used as follows: when highlighting is turned on,
+  ;; ediff-odd/even-diff-face-A/B/C are copied
+  ;; into ediff-odd/even-diff-face-A/B/C-var, and all odd/even overlays become
+  ;; highlighted. When highlighting is turned off, then the face 'default is
+  ;; copied into ediff-odd/even-diff-face-A/B/C-var, thereby unhighlighting all
+  ;; difference regions.
+  (make-face 'ediff-even-diff-face-A-var)
+  (make-face 'ediff-even-diff-face-B-var)
+  (make-face 'ediff-even-diff-face-C-var)
+  (make-face 'ediff-odd-diff-face-A-var)
+  (make-face 'ediff-odd-diff-face-B-var)
+  (make-face 'ediff-odd-diff-face-C-var)
+  
+  ;; initialize *-var faces
+  (defun ediff-init-var-faces ()
+    (copy-face (if (and ediff-use-faces ediff-highlight-all-diffs)
+		   ediff-even-diff-face-A 'default)
+	       'ediff-even-diff-face-A-var)
+    (copy-face (if (and ediff-use-faces ediff-highlight-all-diffs)
+		   ediff-even-diff-face-B 'default)
+	       'ediff-even-diff-face-B-var)
+    (copy-face (if (and ediff-use-faces ediff-highlight-all-diffs)
+		   ediff-even-diff-face-C 'default)
+	       'ediff-even-diff-face-C-var)
+    (copy-face (if (and ediff-use-faces ediff-highlight-all-diffs)
+		   ediff-odd-diff-face-A 'default)
+	       'ediff-odd-diff-face-A-var)
+    (copy-face (if (and ediff-use-faces ediff-highlight-all-diffs)
+		   ediff-odd-diff-face-B 'default)
+	       'ediff-odd-diff-face-B-var)
+    (copy-face (if (and ediff-use-faces ediff-highlight-all-diffs)
+		   ediff-odd-diff-face-C 'default)
+	       'ediff-odd-diff-face-C-var)
+    )
+      
+
+;;; Overlays
+
+  (ediff-defvar-local ediff-current-diff-overlay-A nil
+    "Overlay for the current difference region in buffer A.")
+  (ediff-defvar-local ediff-current-diff-overlay-B nil
+    "Overlay for the current difference region in buffer B.")
+  (ediff-defvar-local ediff-current-diff-overlay-C nil
+    "Overlay for the current difference region in buffer C.")
+  
+  (defun ediff-make-current-diff-overlay (type)
+    (let ((overlay (intern (format "ediff-current-diff-overlay-%S" type)))
+	  (buffer (ediff-get-buffer type))
+	  (face (face-name
+		 (symbol-value
+		  (intern (format "ediff-current-diff-face-%S" type))))))
+      (set overlay
+	   (ediff-make-bullet-proof-overlay (point-max) (point-max) buffer))
+      (ediff-overlay-put (symbol-value overlay) 'face face)
+      (ediff-overlay-put (symbol-value overlay) 'ediff ediff-control-buffer)
+      ))
+	
+  ;; Compute priority of ediff overlay.
+  (defun ediff-highest-priority (start end buffer)
+    (let ((pos (max 1 (1- start)))
+	  ovr-list)
+      (if ediff-xemacs-p
+	  (1+ ediff-shadow-overlay-priority)
+	(ediff-eval-in-buffer buffer
+	  (while (< pos (min (point-max) (1+ end)))
+	    (setq ovr-list (append (overlays-at pos) ovr-list))
+	    (setq pos (next-overlay-change pos)))
+	  (1+ (apply '+
+		     (mapcar (function
+			      (lambda (ovr)
+				(if ovr
+				    (or (ediff-overlay-get ovr 'priority) 0)
+				  0)))
+			     ovr-list)
+		     ))
+	  ))))
+
+)  ; end of window-system-only code.
+  
+    
+(defvar ediff-toggle-read-only-function nil
+  "*Specifies the function to be used to toggle read-only.
+If nil, Ediff tries to deduce the function from the binding of C-x C-q.
+Normally, this is the `toggle-read-only' function, but, if version
+control is used, it could be `vc-toggle-read-only' or `rcs-toggle-read-only'.")
+
+(ediff-defvar-local ediff-file-checked-out-flag nil
+  "If t, indicates that buffer has been already checked out.")
+  
+
+
+;;; Misc
+
+;; when emacs will have before/after-string in overlays, this variable will
+;; be deleted
+(defconst ediff-saved-variables
+  '(;;buffer-read-only
+    buffer-auto-save-file-name)
+  "Buffer-local variables saved and restored during an Ediff session.")
+
+;; to be deleted in due time
+(defconst ediff-working-values '(nil)
+  "Values to be assigned to `ediff-saved-variables' during diff.")
+  
+;; if nil, this silences some messages
+(defconst ediff-verbose-p t)
+  
+(defvar ediff-no-emacs-help-in-control-buffer nil
+  "*Non-nil means C-h should not invoke Emacs help in control buffer.
+Instead, C-h jumps to previous difference.")
+  
+(defvar ediff-temp-file-prefix
+  (let ((env (or (getenv "TMPDIR")
+		 (getenv "TMP")
+		 (getenv "TEMP")))
+	d)
+    (setq d (if (and env (> (length env) 0))
+		env
+	      (if (memq system-type '(vax-vms axp-vms))
+		  "SYS$SCRATCH:"
+		"/tmp")))
+    ;; The following is to make sure we get something to which we can
+    ;; add directory levels on VMS.
+    (setq d (file-name-as-directory (directory-file-name d)))
+    ;;(concat d "ediff")
+    )
+  "*Prefix to put on Ediff temporary file names.
+Do not start with `~/' or `~user-name/'.")  
+
+(defvar ediff-temp-file-mode 384	; u=rw only
+  "*Mode for Ediff temporary files.")
+  
+;; Metacharacters that have to be protected from the shell when executing
+;; a diff/diff3 command.
+(defvar ediff-metachars "[ \t\n!\"#$&'()*;<=>?[\\^`{|~]"
+  "Characters that must be quoted with \\ when used in a shell command line.
+More precisely, a regexp to match any one such character.")
+
+  
+(ediff-defvar-local ediff-temp-file-A nil
+  "Temporary file used for refining difference regions in buffer A.")
+(ediff-defvar-local ediff-temp-file-B nil
+  "Temporary file used for refining difference regions in buffer B.")
+(ediff-defvar-local ediff-temp-file-C nil
+  "Temporary file used for refining difference regions in buffer C.")
+
+;;; In-line functions
+
+(defsubst ediff-file-remote-p (file-name)
+  (if (fboundp ediff-ange-ftp-ftp-name)
+      (funcall ediff-ange-ftp-ftp-name file-name)))
+
+(defsubst ediff-frame-has-menubar ()
+  (and window-system
+       (if ediff-xemacs-p
+	   current-menubar
+	 (let ((lines (cdr (assq 'menu-bar-lines
+				 (frame-parameters (ediff-selected-frame))))))
+	   (or (eq lines t) (and (numberp lines) (< 0 lines))))
+	 )))
+    
+(defsubst ediff-frame-unsplittable-p (frame)
+  (cdr (assq 'unsplittable (ediff-frame-parameters frame))))
+
+(defsubst ediff-get-next-window (wind prev-wind)
+  (or (window-live-p wind)
+      (setq wind (if prev-wind
+		     (next-window wind)
+		   (selected-window)))))
+
+(defsubst ediff-convert-diffs-to-overlays (diff-list)
+  (ediff-set-diff-overlays-in-one-buffer 'A diff-list)
+  (ediff-set-diff-overlays-in-one-buffer 'B diff-list)
+  (if ediff-3way-job
+      (ediff-set-diff-overlays-in-one-buffer 'C diff-list))
+  (message "Processing difference regions ... done"))
+  
+
+(defsubst ediff-kill-buffer-carefully (buf)
+  "Kill buffer BUF if it exists."
+  (if (ediff-buffer-live-p buf)
+      (kill-buffer (get-buffer buf))))
+      
+
+(defsubst ediff-highlight-diff (n)
+  "Put face on diff N.  Invoked for X displays only."
+  (ediff-highlight-diff-in-one-buffer n 'A)
+  (ediff-highlight-diff-in-one-buffer n 'B)
+  (ediff-highlight-diff-in-one-buffer n 'C))
+
+
+(defsubst ediff-unhighlight-diff ()
+  "Remove overlays from buffers A, B, and C."
+  (ediff-unhighlight-diff-in-one-buffer 'A)
+  (ediff-unhighlight-diff-in-one-buffer 'B)
+  (ediff-unhighlight-diff-in-one-buffer 'C))
+    
+;; delete highlighting overlays, restore faces to their original form
+(defsubst ediff-unhighlight-diffs-totally ()
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'A)
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'B)
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'C))
+    
+      
+;; arg is a record for a given diff in a difference vector
+;; this record is itself a vector
+(defsubst ediff-clear-fine-diff-vector (diff-record)
+  (if diff-record
+      (mapcar 'ediff-delete-overlay
+	      (ediff-get-fine-diff-vector-from-diff-record diff-record))))
+	      
+(defsubst ediff-clear-fine-differences-in-one-buffer (n buf-type)
+  (ediff-clear-fine-diff-vector (ediff-get-difference n buf-type))
+  (ediff-set-fine-diff-vector n buf-type nil))
+  
+(defsubst ediff-clear-fine-differences (n)
+  (ediff-clear-fine-differences-in-one-buffer n 'A)
+  (ediff-clear-fine-differences-in-one-buffer n 'B)
+  (if ediff-3way-job
+      (ediff-clear-fine-differences-in-one-buffer n 'C)))
+	  
+
+(defsubst ediff-convert-fine-diffs-to-overlays (diff-list region-num)
+  (ediff-set-fine-overlays-in-one-buffer 'A diff-list region-num)
+  (ediff-set-fine-overlays-in-one-buffer 'B diff-list region-num)
+  (if ediff-3way-job
+      (ediff-set-fine-overlays-in-one-buffer 'C diff-list region-num)
+    ))
+  
+(defsubst ediff-mouse-event-p (event)
+  (if ediff-xemacs-p
+      (button-event-p event)
+    (string-match "mouse" (format "%S" (event-basic-type event)))
+    ))
+    
+(defsubst ediff-frame-iconified-p (frame)
+  (if (and window-system (ediff-frame-live-p frame))
+      (if ediff-xemacs-p
+	  (screen-iconified-p frame)
+	(eq (frame-visible-p frame) 'icon))))
+    
+(defsubst ediff-window-visible-p (wind)
+  (and (window-live-p wind)
+       ;; under non-wondow system, window-live-p also means window is visible
+       (or (not window-system)
+	   (ediff-frame-visible-p (ediff-window-frame wind)))))
+  
+
+(defsubst ediff-frame-char-width (frame)
+  (if ediff-xemacs-p
+      (/ (screen-pixel-width frame) (screen-width frame))
+    (frame-char-width frame)))
+    
+(defsubst ediff-frame-char-height (frame)
+  (if ediff-xemacs-p
+      (/ (screen-pixel-height frame) (screen-height frame))
+    (frame-char-height frame)))
+    
+
+(defsubst ediff-empty-overlay-p (overl)
+  (= (ediff-overlay-start overl) (ediff-overlay-end overl)))
+  
+;; t if diff region is empty.
+;; In case of buffer C, t also if it is not a 3way
+;; comparison job (merging jobs return t as well).
+(defun ediff-empty-diff-region-p (n buf-type)
+  (if (eq buf-type 'C)
+      (or (not ediff-3way-comparison-job)
+	  (= (ediff-get-diff-posn 'C 'beg n)
+	     (ediff-get-diff-posn 'C 'end n)))
+    (= (ediff-get-diff-posn buf-type 'beg n)
+       (ediff-get-diff-posn buf-type 'end n))))
+       
+;; Test if diff region is white space only.
+;; If 2-way job and buf-type = C, then returns t.
+(defun ediff-whitespace-diff-region-p (n buf-type)
+  (or (and (eq buf-type 'C) (not ediff-3way-job))
+      (let ((beg (ediff-get-diff-posn buf-type 'beg n))
+	    (end (ediff-get-diff-posn buf-type 'end n)))
+	(ediff-eval-in-buffer (ediff-get-buffer buf-type)
+	  (save-excursion
+	    (goto-char beg)
+	    (skip-chars-forward ediff-whitespace)
+	    (>= (point) end))))))
+	    
+;; temporarily uses DIR to abbreviate file name
+;; if DIR is nil, use default-directory
+(defsubst ediff-abbreviate-filename (file dir)
+  (let* ((dir (or dir default-directory))
+	 (directory-abbrev-alist (list (cons dir ""))))
+    (abbreviate-file-name file)))
+    
+(defsubst ediff-get-region-contents (n buf-type ctrl-buf &optional start end)
+  (ediff-eval-in-buffer 
+      (ediff-eval-in-buffer ctrl-buf (ediff-get-buffer buf-type))
+    (buffer-substring
+     (or start (ediff-get-diff-posn buf-type 'beg n ctrl-buf))
+     (or end (ediff-get-diff-posn buf-type 'end n ctrl-buf)))))
+  
+;; If ediff modified mode line, strip the modification
+(defsubst ediff-strip-mode-line-format ()
+  (if (member (car mode-line-format) '(" A: " " B: " " C: "))
+      (setq mode-line-format (nth 2 mode-line-format))))
+
+;; Verify that we have a difference selected.
+(defsubst ediff-valid-difference-p (&optional n)
+  (or n (setq n ediff-current-difference))
+  (and (>= n 0) (< n ediff-number-of-differences)))
+  
+(defsubst ediff-show-all-diffs (n)
+  "Don't skip difference regions."
+  nil)
+     
+(provide 'ediff-init)
+
+
+;;; ediff-init.el  ends here
diff --git a/lisp/ediff-merg.el b/lisp/ediff-merg.el
new file mode 100644
index 00000000000..92235b640dc
--- /dev/null
+++ b/lisp/ediff-merg.el
@@ -0,0 +1,259 @@
+;;; ediff-merg.el --- merging utilities
+;;; Copyright (C) 1994 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+(require 'ediff-init)
+
+
+(defvar ediff-default-variant 'default-A
+  "*The variant to be used as a default for buffer C in merging.
+Valid values are the symbols `default-A', `default-B', and `combined'.")
+
+(defvar ediff-combination-pattern 
+  '("#ifdef NEW /* variant A */" "#else /* variant B */" "#endif /* NEW */")
+  "*Pattern to be used for combining difference regions in buffers A and B.
+The value is (STRING1 STRING2 STRING3). The combined text will look like this:
+
+STRING1
+diff region from variant A
+STRING2
+diff region from variant B
+STRING3
+")
+
+(ediff-defvar-local ediff-show-clashes-only  nil
+  "*If t, show only those diff regions where both buffers disagree with the ancestor.
+This means that regions that have status prefer-A or prefer-B will be
+skiped over. Nil means show all regions.")
+
+	
+(defsubst ediff-get-combined-region (n)
+  (concat (nth 0 ediff-combination-pattern) "\n"
+	  (ediff-get-region-contents n 'A ediff-control-buffer)
+	  (nth 1 ediff-combination-pattern) "\n"
+	  (ediff-get-region-contents n 'B ediff-control-buffer)
+	  (nth 2 ediff-combination-pattern) "\n"))
+    
+(defsubst ediff-set-state-of-all-diffs-in-all-buffers (ctl-buf)
+  (let ((n 0))
+    (while (< n ediff-number-of-differences)
+      (ediff-set-state-of-diff-in-all-buffers n ctl-buf)
+      (setq n (1+ n)))))
+     
+(defun ediff-set-state-of-diff-in-all-buffers (n ctl-buf)
+  (let ((regA (ediff-get-region-contents n 'A ctl-buf))
+	(regB (ediff-get-region-contents n 'B ctl-buf))
+	(regC (ediff-get-region-contents n 'C ctl-buf)))
+    (cond ((string= regA regB)
+	   (ediff-set-state-of-diff n 'A "=diff(B)")
+	   (ediff-set-state-of-diff n 'B "=diff(A)")
+	   (ediff-set-state-of-diff n 'C nil))
+	  ((string= regA regC)
+	   (ediff-set-state-of-diff n 'A "=diff(C)")
+	   (ediff-set-state-of-diff n 'C "=diff(A)")
+	   (ediff-set-state-of-diff n 'B nil))
+	  ((string= regB regC)
+	   (ediff-set-state-of-diff n 'C "=diff(B)")
+	   (ediff-set-state-of-diff n 'B "=diff(C)")
+	   (ediff-set-state-of-diff n 'A nil))
+	  ((string= regC (ediff-get-combined-region n))
+	   (ediff-set-state-of-diff n 'A nil)
+	     (ediff-set-state-of-diff n 'B nil)
+	     (ediff-set-state-of-diff n 'C "=diff(A+B)"))
+	  (t (ediff-set-state-of-diff n 'A nil)
+	     (ediff-set-state-of-diff n 'B nil)
+	     (ediff-set-state-of-diff n 'C nil)))
+    ))
+	
+;; Go over all diffs starting with DIFF-NUM and copy regions into buffer C
+;; according to the state of the difference.
+;; Since ediff-copy-diff refuses to copy identical diff regions, there is
+;; no need to optimize ediff-do-merge any further.
+;;
+;; If re-merging, change state of merge in all diffs starting with
+;; DIFF-NUM, except those where the state is prefer-* or where it is
+;; default-* but the region appears to be modified with respect to its
+;; original form.
+;; Also, prevent copying when there is a danger of overriding a modified
+;; region in buffer C.
+(defun ediff-do-merge (diff-num &optional remerging)
+  (if (< diff-num 0) (setq diff-num 0))
+  (let ((n diff-num)
+	(default-state-of-merge (format "%S" ediff-default-variant))
+	do-not-copy
+	state-of-merge)
+      
+    (while (< n ediff-number-of-differences)
+    
+      (if (= (mod n 10) 0)
+	  (message "%s buffers A & B into C ... region %d of %d"
+		   (if remerging "Re-merging" "Merging")
+		   n
+		   ediff-number-of-differences))
+	     
+      (setq state-of-merge (ediff-get-state-of-merge n))
+      (setq do-not-copy (string= state-of-merge default-state-of-merge))
+
+      (if remerging
+	  (let ((reg-A (ediff-get-region-contents n 'A ediff-control-buffer))
+		(reg-B (ediff-get-region-contents n 'B ediff-control-buffer))
+		(reg-C (ediff-get-region-contents n 'C ediff-control-buffer)))
+		
+	    (if (or 
+		 ;; has been edited since it was first set by default
+		 (and (string= state-of-merge "default-A")
+		      (not (string= reg-A reg-C)))
+		 ;; has been edited since first set by default
+		 (and (string= state-of-merge "default-B")
+		      (not (string= reg-B reg-C)))
+		 ;; was prefered--ignore
+		 (string-match "prefer" state-of-merge)
+		 ;; was combined--ignore
+		 (string= state-of-merge "combined"))
+		
+		(setq do-not-copy t))
+		
+	    ;; change state of merge for this diff, if necessary
+	    (if (and (string-match "default" state-of-merge) (not do-not-copy))
+		(ediff-set-state-of-merge
+		 n (format "%S" ediff-default-variant)))
+	    ))
+	  
+      ;; state-of-merge may have changed via ediff-set-state-of-merge, so
+      ;; check it out again
+      (setq state-of-merge (ediff-get-state-of-merge n))
+      
+      (or do-not-copy
+	  (if (string= state-of-merge "combined")
+	      ;; use n+1 because ediff-combine-diffs works via user numbering
+	      ;; of diffs, which is 1+ to what ediff uses internally
+	      (ediff-combine-diffs (1+ n) 'batch)
+	    (ediff-copy-diff n
+			     (if (string-match "-A" state-of-merge) 'A 'B)
+			     'C
+			     'batch)))
+      (setq n (1+ n)))
+    (message "Merging buffers A & B into C ... Done")
+    ))
+    
+
+(defun ediff-re-merge ()
+  "Remerge unmodified diff regions using a new default. Start with the current region."
+  (interactive)
+  (let* ((default-variant-alist
+	   (list '("default-A") '("default-B") '("combined")))
+	 (actual-alist
+	  (delete (list (symbol-name ediff-default-variant))
+		  default-variant-alist)))
+    (setq ediff-default-variant
+	  (intern
+	   (completing-read 
+	    (format "Current merge default is `%S'. New default: "
+		    ediff-default-variant)
+	    actual-alist nil 'must-match)))
+    (ediff-do-merge ediff-current-difference 'remerge)
+    (ediff-recenter)
+  ))
+    
+(defun ediff-shrink-window-C (arg)
+  "Shrink window C to just one line.
+With a prefix argument, returns window C to its normal size.
+Used only for merging jobs."
+  (interactive "P")
+  (if (not ediff-merge-job)
+      (error "ediff-shrink-window-C can be used only for merging jobs"))
+  (cond ((eq arg '-) (setq arg -1))
+	((not (numberp arg)) (setq arg nil)))
+  (cond ((null arg)
+	 (let ((ediff-merge-window-share
+		(if (< (window-height ediff-window-C) 3)
+		    ediff-merge-window-share 0)))
+	   (setq ediff-window-config-saved "") ; force redisplay
+	   (ediff-recenter 'no-rehighlight)))
+	((and (< arg 0) (> (window-height ediff-window-C) 2))
+	 (setq ediff-merge-window-share (* ediff-merge-window-share 0.9))
+	 (setq ediff-window-config-saved "") ; force redisplay
+	 (ediff-recenter 'no-rehighlight))
+	((and (> arg 0) (> (window-height ediff-window-A) 2))
+	 (setq ediff-merge-window-share (* ediff-merge-window-share 1.1))
+	 (setq ediff-window-config-saved "") ; force redisplay
+	 (ediff-recenter 'no-rehighlight))))
+
+
+;; N here is the user's region number. It is 1+ what Ediff uses internally.
+(defun ediff-combine-diffs (n &optional batch-invocation)
+  "Combine Nth diff regions of buffers A and B and place the combination in C.
+Combining is done using the list in variable `ediff-combination-pattern'."
+  (interactive "P")
+  (setq n (if n (1- n) ediff-current-difference))
+  
+  (let (regA regB reg-combined)
+    (setq regA (ediff-get-region-contents n 'A ediff-control-buffer)
+	  regB (ediff-get-region-contents n 'B ediff-control-buffer))
+    
+    (setq reg-combined (concat (nth 0 ediff-combination-pattern) "\n"
+			       regA
+			       (nth 1 ediff-combination-pattern) "\n"
+			       regB
+			       (nth 2 ediff-combination-pattern) "\n"))
+    
+    (ediff-copy-diff n nil 'C batch-invocation reg-combined))
+    
+    (or batch-invocation
+	(ediff-recenter 'no-rehighlight)))
+
+
+;; Checks if the region in buff C looks like a combination of the regions
+;; in buffers A and B. Returns a list (reg-a-beg reg-a-end reg-b-beg reg-b-end)
+;; These refer to where the copies of region A and B start and end in buffer C
+(defun ediff-looks-like-combined-merge (region-num)
+  (if ediff-merge-job
+      (let ((combined (string-match (regexp-quote "(A+B)")
+				    (or (ediff-get-state-of-diff region-num 'C)
+					"")))
+	    (reg-beg (ediff-get-diff-posn 'C 'beg region-num))
+	    (reg-end (ediff-get-diff-posn 'C 'end region-num))
+	    (pat1 (nth 0 ediff-combination-pattern))
+	    (pat2 (nth 1 ediff-combination-pattern))
+	    (pat3 (nth 2 ediff-combination-pattern))
+	    reg-a-beg reg-a-end reg-b-beg reg-b-end reg-c-beg reg-c-end)
+	
+	(if combined
+	    (ediff-eval-in-buffer ediff-buffer-C
+	      (goto-char reg-beg)
+	      (search-forward pat1 reg-end 'noerror)
+	      (setq reg-a-beg (match-beginning 0))
+	      (setq reg-a-end (match-end 0))
+	      (search-forward pat2 reg-end 'noerror)
+	      (setq reg-b-beg (match-beginning 0))
+	      (setq reg-b-end (match-end 0))
+	      (search-forward pat3 reg-end 'noerror)
+	      (setq reg-c-beg (match-beginning 0))
+	      (setq reg-c-end (match-end 0))))
+	
+	(if (and reg-a-beg reg-a-end reg-b-beg reg-b-end)
+	    (list reg-a-beg reg-a-end reg-b-beg reg-b-end reg-c-beg reg-c-end))
+	)))
+  
+
+(provide 'ediff-merg)
+
+;; ediff-merg.el ends here
diff --git a/lisp/ediff-util.el b/lisp/ediff-util.el
new file mode 100644
index 00000000000..ba02bc1588f
--- /dev/null
+++ b/lisp/ediff-util.el
@@ -0,0 +1,3398 @@
+;;; ediff-util.el --- the core commands and utilities of ediff
+;;; Copyright (C) 1994 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+;;; Code:
+
+(require 'ediff-init)
+
+
+;;; Functions
+
+(defun ediff-mode ()
+  "Ediff mode is used by the Ediff file-difference package.
+It is entered only through one of the following commands:
+	`ediff'
+	`ediff-files'
+	`ediff-buffers'
+	`ediff3'
+	`ediff-files3'
+	`ediff-buffers3'
+	`ediff-merge'
+	`ediff-merge-files'
+	`ediff-merge-files-with-ancestor'
+	`ediff-merge-buffers'
+	`ediff-merge-buffers-with-ancestor'
+	`ediff-merge-revisions'
+	`ediff-merge-revisions-with-ancestor'
+	`ediff-windows'
+	`ediff-small-regions'
+	`ediff-large-regions'
+	`epatch'
+	`ediff-patch-file'
+	`ediff-patch-buffer'
+	`epatch-buffer'
+	`ediff-revision'
+
+Commands:
+\\{ediff-mode-map}"
+  (kill-all-local-variables)
+  (setq major-mode 'ediff-mode)
+  (setq mode-name "Ediff")
+  (run-hooks 'ediff-mode-hooks))
+
+(defun ediff-version ()
+  "Return string describing the version of Ediff.
+When called interactively, displays the version."
+  (interactive)
+  (if (interactive-p)
+      (message (ediff-version))
+    (format "Ediff %s of %s" ediff-version ediff-date)))
+    
+    
+(require 'ediff-diff)
+(require 'ediff-merg)
+  
+
+;;; Build keymaps
+
+(ediff-defvar-local ediff-mode-map nil
+  "Local keymap used in Ediff mode.
+This is local to each Ediff Control Panel, so they may vary from invocation
+to invocation.")
+
+;; Set up the keymap in the control buffer
+(defun ediff-set-keys ()
+  "Set up Ediff keymap, if necessary."
+  (if (null ediff-mode-map)
+      (ediff-setup-keymap))
+  (use-local-map ediff-mode-map))
+  
+;; Reload Ediff keymap.  For debugging only.
+(defun ediff-reload-keymap ()
+  (interactive)
+  (setq ediff-mode-map nil)
+  (ediff-set-keys))
+  
+
+(defun ediff-setup-keymap ()
+  "Set up the keymap used in the control buffer of Ediff."
+  (setq ediff-mode-map (make-sparse-keymap))
+  (suppress-keymap ediff-mode-map)
+  
+  (define-key ediff-mode-map "p" 'ediff-previous-difference)
+  (define-key ediff-mode-map "\C-?" 'ediff-previous-difference)
+  (define-key ediff-mode-map [backspace] 'ediff-previous-difference)
+  (define-key ediff-mode-map [delete] 'ediff-previous-difference)
+  (define-key ediff-mode-map "\C-h" (if ediff-no-emacs-help-in-control-buffer
+					'ediff-previous-difference nil))
+  (define-key ediff-mode-map "n" 'ediff-next-difference)
+  (define-key ediff-mode-map " " 'ediff-next-difference)
+  (define-key ediff-mode-map "j" 'ediff-jump-to-difference)
+  (define-key ediff-mode-map "g"  nil)
+  (define-key ediff-mode-map "ga" 'ediff-jump-to-difference-at-point)
+  (define-key ediff-mode-map "gb" 'ediff-jump-to-difference-at-point)
+  (define-key ediff-mode-map "q" 'ediff-quit)
+  (define-key ediff-mode-map "z" 'ediff-suspend)
+  (define-key ediff-mode-map "\C-l" 'ediff-recenter)
+  (define-key ediff-mode-map "|" 'ediff-toggle-split)
+  (define-key ediff-mode-map "h" 'ediff-toggle-hilit)
+  (or ediff-word-mode
+      (define-key ediff-mode-map "@" 'ediff-toggle-autorefine))
+  (if ediff-word-mode-job
+      (define-key ediff-mode-map "%" 'ediff-toggle-narrow-region))
+  (define-key ediff-mode-map "~" 'ediff-swap-buffers)
+  (define-key ediff-mode-map "v" 'ediff-scroll-vertically)
+  (define-key ediff-mode-map "\C-v" 'ediff-scroll-vertically)
+  (define-key ediff-mode-map "^" 'ediff-scroll-vertically)
+  (define-key ediff-mode-map "\M-v" 'ediff-scroll-vertically)
+  (define-key ediff-mode-map "V" 'ediff-scroll-vertically)
+  (define-key ediff-mode-map "<" 'ediff-scroll-horizontally)
+  (define-key ediff-mode-map ">" 'ediff-scroll-horizontally)
+  (define-key ediff-mode-map "i" 'ediff-status-info)
+  (define-key ediff-mode-map "?" 'ediff-toggle-help)
+  (define-key ediff-mode-map "!" 'ediff-update-diffs)
+  (or ediff-word-mode
+      (define-key ediff-mode-map "*" 'ediff-make-or-kill-fine-diffs))
+  (define-key ediff-mode-map "a"  nil)
+  (define-key ediff-mode-map "b"  nil)
+  (define-key ediff-mode-map "r"  nil)
+  (cond (ediff-merge-job
+	 ;; In merging, we allow only A->C and B->C copying.
+	 (define-key ediff-mode-map "a" (function
+					 (lambda (arg)
+					   (interactive "P")
+					   (ediff-diff-to-diff arg "ac"))))
+	 (define-key ediff-mode-map "b" (function
+					 (lambda (arg)
+					   (interactive "P")
+					   (ediff-diff-to-diff arg "bc"))))
+	 (define-key ediff-mode-map "r" (function
+					 (lambda (arg)
+					   (interactive "P")
+					   (ediff-restore-diff arg ?c))))
+	 (define-key ediff-mode-map "s" 'ediff-shrink-window-C)
+	 (define-key ediff-mode-map "+" 'ediff-combine-diffs)
+	 (define-key ediff-mode-map "$" 'ediff-toggle-show-clashes-only)
+	 (define-key ediff-mode-map "&" 'ediff-re-merge))
+	(ediff-3way-comparison-job
+	 (define-key ediff-mode-map "ab" 'ediff-diff-to-diff)
+	 (define-key ediff-mode-map "ba" 'ediff-diff-to-diff)
+	 (define-key ediff-mode-map "ac" 'ediff-diff-to-diff)
+	 (define-key ediff-mode-map "bc" 'ediff-diff-to-diff)
+	 (define-key ediff-mode-map "c" nil)
+	 (define-key ediff-mode-map "ca" 'ediff-diff-to-diff)
+	 (define-key ediff-mode-map "cb" 'ediff-diff-to-diff)
+	 (define-key ediff-mode-map "ra" 'ediff-restore-diff)
+	 (define-key ediff-mode-map "rb" 'ediff-restore-diff)
+	 (define-key ediff-mode-map "rc" 'ediff-restore-diff)
+	 (define-key ediff-mode-map "C"  'ediff-toggle-read-only))
+	(t ; 2-way comparison
+	 (define-key ediff-mode-map "a" (function
+					 (lambda (arg)
+					   (interactive "P")
+					   (ediff-diff-to-diff arg "ab"))))
+	 (define-key ediff-mode-map "b" (function
+					 (lambda (arg)
+					   (interactive "P")
+					   (ediff-diff-to-diff arg "ba"))))
+	 (define-key ediff-mode-map "ra" 'ediff-restore-diff)
+	 (define-key ediff-mode-map "rb" 'ediff-restore-diff))
+	) ; cond
+  (define-key ediff-mode-map "G" 'ediff-submit-report)
+  (define-key ediff-mode-map "#"  nil)
+  (define-key ediff-mode-map "#h"  'ediff-toggle-regexp-match)
+  (define-key ediff-mode-map "#f"  'ediff-toggle-regexp-match)
+  (or ediff-word-mode
+      (define-key ediff-mode-map "##"  'ediff-toggle-skip-similar))
+  (define-key ediff-mode-map "o"   nil)
+  (define-key ediff-mode-map "A"  'ediff-toggle-read-only)
+  (define-key ediff-mode-map "B"  'ediff-toggle-read-only)
+  (define-key ediff-mode-map "w"   nil)
+  (define-key ediff-mode-map "wa"  'ediff-save-buffer)
+  (define-key ediff-mode-map "wb"  'ediff-save-buffer)
+  (define-key ediff-mode-map "wd"  'ediff-save-buffer)
+  (if ediff-3way-job
+      (progn
+	(define-key ediff-mode-map "wc" 'ediff-save-buffer)
+	(define-key ediff-mode-map "gc" 'ediff-jump-to-difference-at-point)
+	))
+
+  (define-key ediff-mode-map "m" 'ediff-toggle-wide-display)
+	
+  (define-key ediff-mode-map "k"   nil)
+  (define-key ediff-mode-map "kkk" 'ediff-reload-keymap) ; for debugging
+  
+  ;; Allow ediff-mode-map to be referenced indirectly
+  (fset 'ediff-mode-map ediff-mode-map)
+  (run-hooks 'ediff-keymap-setup-hooks))
+
+
+;;; Setup functions
+
+(require 'ediff-wind)
+
+;; Common startup entry for all Ediff functions
+(defun ediff-setup (buffer-A file-A buffer-B file-B buffer-C file-C
+			     startup-hooks setup-parameters)
+  (setq file-A (expand-file-name file-A))
+  (setq file-B (expand-file-name file-B))
+  (if (stringp file-C)
+      (setq file-C (expand-file-name file-C)))
+  (let* ((control-buffer-name 
+	  (ediff-unique-buffer-name "*Ediff Control Panel" "*"))
+	 (control-buffer (ediff-eval-in-buffer buffer-A
+			   (get-buffer-create control-buffer-name))))
+    (ediff-eval-in-buffer control-buffer
+      (ediff-mode)                 
+      
+      ;; unwrap set up parameters passed as argument
+      (while setup-parameters
+	(set (car (car setup-parameters)) (cdr (car setup-parameters)))
+	(setq setup-parameters (cdr setup-parameters)))
+	
+      ;; set variables classifying the current ediff job
+      (setq ediff-3way-comparison-job (ediff-3way-comparison-job)
+	    ediff-merge-job (ediff-merge-job)
+	    ediff-merge-with-ancestor-job (ediff-merge-with-ancestor-job)
+	    ediff-3way-job (ediff-3way-job)
+	    ediff-diff3-job (ediff-diff3-job)
+	    ediff-word-mode-job (ediff-word-mode-job))
+	
+      (make-local-variable 'ediff-prefer-long-help-message)
+      (make-local-variable 'ediff-prefer-iconified-control-frame)
+      (make-local-variable 'ediff-split-window-function)
+      (make-local-variable 'ediff-default-variant)
+      (make-local-variable 'ediff-merge-window-share)
+      
+      ;; adjust for merge jobs
+      (if ediff-merge-job
+	  (let ((buf
+		 ;; Use buf A even if `combined'. The right stuff is
+		 ;; inserted by ediff-do-merge
+		 (if (eq ediff-default-variant 'default-B) buffer-B buffer-A)))
+		 
+	    (setq ediff-split-window-function
+		  ediff-merge-split-window-function) 
+	    
+	    ;; remember the ancestor buffer, if any
+	    (setq ediff-ancestor-buffer buffer-C)
+	    
+	    (setq buffer-C
+		  (get-buffer-create
+		   (ediff-unique-buffer-name "*ediff-merge" "*")))
+	    (save-excursion
+	      (set-buffer buffer-C)
+	      (insert-buffer buf))))
+      (setq buffer-read-only nil    
+	    ediff-buffer-A buffer-A
+	    ediff-buffer-B buffer-B
+	    ediff-buffer-C buffer-C
+	    ediff-control-buffer control-buffer)
+	   
+      (setq ediff-control-buffer-suffix
+	    (if (string-match "<[0-9]*>" control-buffer-name)
+		(substring control-buffer-name
+			   (match-beginning 0) (match-end 0))
+	      "")
+	    ediff-control-buffer-number
+	    (max
+	     0
+	     (1-
+	      (string-to-number
+	       (substring
+		ediff-control-buffer-suffix
+		(or
+		 (string-match "[0-9]+" ediff-control-buffer-suffix)
+		 0))))))
+	   
+      (setq ediff-error-buffer (get-buffer-create (ediff-unique-buffer-name
+						   "*ediff-errors" "*")))
+      
+      (ediff-eval-in-buffer buffer-A (ediff-strip-mode-line-format))
+      (ediff-eval-in-buffer buffer-B (ediff-strip-mode-line-format))
+      (if ediff-3way-job
+	  (ediff-eval-in-buffer buffer-C (ediff-strip-mode-line-format)))
+      
+      (ediff-save-protected-variables) ; save variables to be restored on exit
+      
+      ;; This will be deleted when emacs gets before/after strings
+      (ediff-remember-buffer-characteristics t) ; remember at setup
+	
+      ;; ediff-setup-diff-regions-function must be set after setup
+      ;; parameters are processed.
+      (setq ediff-setup-diff-regions-function
+	    (if ediff-diff3-job
+		'ediff-setup-diff-regions3
+	      'ediff-setup-diff-regions))
+	
+      (if ediff-xemacs-p
+	  ()
+	(make-local-variable 'default-minibuffer-frame))
+      
+      (setq ediff-wide-bounds
+	    (list (ediff-make-bullet-proof-overlay
+		   '(point-min) '(point-max) ediff-buffer-A)
+		  (ediff-make-bullet-proof-overlay
+		   '(point-min) '(point-max) ediff-buffer-B)
+		  (ediff-make-bullet-proof-overlay
+		   '(point-min) '(point-max) ediff-buffer-C)))
+      
+      ;; This has effect only on ediff-windows/regions
+      ;; In all other cases, ediff-visible-region sets visibility bounds to
+      ;; ediff-wide-bounds, and ediff-narrow-bounds are ignored.
+      (if ediff-start-narrowed
+	  (setq ediff-visible-bounds ediff-narrow-bounds)
+	(setq ediff-visible-bounds ediff-wide-bounds))
+      
+      (ediff-set-keys) ; comes after parameter setup
+      
+      ;; set up ediff-narrow-bounds, if not set
+      (or ediff-narrow-bounds
+	  (setq ediff-narrow-bounds ediff-wide-bounds))
+      
+      ;; The following will go away once before/after-string overlay
+      ;; properties are added to emacs 19. The only thing that will remain
+      ;; are the calls to ediff-prepare-buffer-hooks, nuking the selective
+      ;; display, and setting files A/B r/o for merge.
+      
+      ;; All these must be inside ediff-eval-in-buffer control-buffer,
+      ;; since these vars are local to control-buffer
+      ;; These won't run if there are errors in diff
+      (ediff-eval-in-buffer ediff-buffer-A
+	(ediff-nuke-selective-display)
+	(run-hooks 'ediff-prepare-buffer-hooks)
+	(if (ediff-eval-in-buffer control-buffer ediff-merge-job)
+	    (setq buffer-read-only t))
+	(add-hook 'local-write-file-hooks 'ediff-block-write-file)
+	(setq before-change-function 'ediff-before-change-guard)
+	;; add control-buffer to the list of sessions
+	(or (memq control-buffer ediff-this-buffer-control-sessions)
+	    (setq ediff-this-buffer-control-sessions
+		  (cons control-buffer ediff-this-buffer-control-sessions)))
+	)
+      (ediff-eval-in-buffer ediff-buffer-B
+	(ediff-nuke-selective-display)
+	(run-hooks 'ediff-prepare-buffer-hooks)
+	(if (ediff-eval-in-buffer control-buffer ediff-merge-job)
+	    (setq buffer-read-only t))
+	(add-hook 'local-write-file-hooks 'ediff-block-write-file)
+	(setq before-change-function 'ediff-before-change-guard)
+	;; add control-buffer to the list of sessions
+	(or (memq control-buffer ediff-this-buffer-control-sessions)
+	    (setq ediff-this-buffer-control-sessions
+		  (cons control-buffer ediff-this-buffer-control-sessions)))
+	)
+      (if ediff-3way-job
+	  (ediff-eval-in-buffer ediff-buffer-C
+	    (ediff-nuke-selective-display)
+	    (run-hooks 'ediff-prepare-buffer-hooks)
+	    (add-hook 'local-write-file-hooks 'ediff-block-write-file)
+	    (setq before-change-function 'ediff-before-change-guard)
+	    ;; add control-buffer to the list of sessions
+	    (or (memq control-buffer ediff-this-buffer-control-sessions)
+		(setq ediff-this-buffer-control-sessions
+		      (cons control-buffer
+			    ediff-this-buffer-control-sessions))) 
+	    ))
+      
+      ;; must come after setting up  ediff-narrow-bounds AND after
+      ;; nuking selective display
+      (funcall ediff-setup-diff-regions-function file-A file-B file-C)
+      (setq ediff-number-of-differences (length ediff-difference-vector-A))
+      (setq ediff-current-difference -1)
+      
+      (ediff-make-current-diff-overlay 'A)
+      (ediff-make-current-diff-overlay 'B)
+      (if ediff-3way-job
+	  (ediff-make-current-diff-overlay 'C))
+	  
+      (if window-system
+	  (ediff-init-var-faces))
+	  
+      (ediff-setup-windows buffer-A buffer-B buffer-C control-buffer)
+      
+      (let ((shift-A (ediff-overlay-start
+		      (ediff-get-value-according-to-buffer-type
+		       'A ediff-narrow-bounds)))
+	    (shift-B (ediff-overlay-start
+		      (ediff-get-value-according-to-buffer-type
+		       'B ediff-narrow-bounds)))
+	    (shift-C (ediff-overlay-start
+		      (ediff-get-value-according-to-buffer-type
+		       'C ediff-narrow-bounds))))
+	;; position point in buf A
+	(save-excursion
+	  (select-window ediff-window-A)
+	  (goto-char shift-A))
+	;; position point in buf B
+	(save-excursion
+	  (select-window ediff-window-B)
+	  (goto-char shift-B))
+	(if ediff-3way-job
+	    (save-excursion
+	      (select-window ediff-window-C)
+	      (goto-char shift-C)))
+	)
+      
+      (select-window ediff-control-window)
+      (ediff-visible-region)
+      
+      ;; The following is a hack to placate OS/2
+      ;; The problem is that OS/2 doesn't let us delete files used by other
+      ;; processes. Thus, in ediff-buffers and other functions, we can't
+      ;; delete temp files because they might be used by the asynchronous
+      ;; process that computes custom diffs. So, under OS/1 we have to wait
+      ;; for some time until custom diffs are done.
+      (if (eq system-type 'emx)
+	  (ediff-eval-in-buffer ediff-custom-diff-buffer
+	    (let ((proc (get-buffer-process (current-buffer))))
+	      (while (and (processp proc)
+			  (eq (process-status proc) 'run))
+		(message "Waiting for the diff program to quit")
+		(sleep-for 1)
+		)
+	      (message "")
+	      )))
+      
+      (run-hooks 'startup-hooks 'ediff-startup-hooks)
+      (ediff-refresh-mode-lines)
+      (setq buffer-read-only t))))
+      
+      
+;; This function assumes that we are in the window where control buffer is
+;; to reside. 
+(defun ediff-setup-control-buffer (ctl-buf)
+  "Set up window for control buffer."
+  (if (window-dedicated-p (selected-window))
+      (set-buffer ctl-buf) ; we are in control frame but just in case
+    (switch-to-buffer ctl-buf))
+  (let ((window-min-height 1))
+    (erase-buffer)
+    (ediff-set-help-message)
+    (insert ediff-help-message)
+    (shrink-window-if-larger-than-buffer)
+    (if (not ediff-multiframe)
+	(ediff-indent-help-message))
+    (set-buffer-modified-p nil)
+    (ediff-refresh-mode-lines)
+    (setq ediff-control-window (selected-window))
+    (setq ediff-window-config-saved
+	  (format "%S%S%S%S%S"
+		  ediff-control-window
+		  ediff-window-A
+		  ediff-window-B
+		  ediff-window-C
+		  ediff-split-window-function))
+    (goto-char (point-min))
+    (skip-chars-forward ediff-whitespace)))
+    
+;; assuming we are in control window, calculate length of the first line in
+;; help message
+(defun ediff-help-message-line-length ()
+  (save-excursion
+    (goto-char (point-min))
+    (if ediff-prefer-long-help-message
+	(next-line 1))
+    (end-of-line)
+    (current-column)))
+    
+    
+(defun ediff-indent-help-message ()
+  (let* ((shift (/ (max 0 (- (ediff-frame-width (ediff-selected-frame))
+			     (ediff-help-message-line-length)))
+		   2))
+	 (str (make-string shift ?\ )))
+    (save-excursion
+      (goto-char (point-min))
+      (while (< (point) (point-max))
+	(insert str)
+	(beginning-of-line)
+	(forward-line 1)))))
+      
+
+(defun ediff-set-help-message ()
+  (setq ediff-long-help-message
+	(cond ((and ediff-long-help-message-custom
+		    (or (symbolp ediff-long-help-message-custom)
+			(consp ediff-long-help-message-custom)))
+	       (funcall ediff-long-help-message-custom))
+	      (ediff-word-mode 
+	       (concat ediff-long-help-message-head
+		       ediff-long-help-message-word-mode
+		       ediff-long-help-message-tail))
+	      (ediff-merge-job 
+	       (concat ediff-long-help-message-head
+		       ediff-long-help-message-merge
+		       ediff-long-help-message-tail))
+	      (ediff-diff3-job
+	       (concat ediff-long-help-message-head
+		       ediff-long-help-message-compare3
+		       ediff-long-help-message-tail))
+	      (t 
+	       (concat ediff-long-help-message-head
+		       ediff-long-help-message-compare2
+		       ediff-long-help-message-tail))))
+  (setq ediff-brief-help-message 
+	(cond ((and ediff-brief-help-message-custom
+		    (or (symbolp ediff-brief-help-message-custom)
+			(consp ediff-brief-help-message-custom)))
+	       (funcall ediff-brief-help-message-custom))
+	      ((stringp ediff-brief-help-message-custom)
+	       ediff-brief-help-message-custom)
+	      ((ediff-multiframe-setup-p) ediff-brief-message-string)
+	      (t ; long brief msg, not multiframe --- put in the middle
+	       ediff-brief-message-string)
+	      ))
+  (setq ediff-help-message (if ediff-prefer-long-help-message
+			       ediff-long-help-message
+			     ediff-brief-help-message))
+  (run-hooks 'ediff-display-help-hooks)
+  )
+
+
+
+
+;;; Commands for working with Ediff
+     
+(defun ediff-update-diffs ()
+  "Recompute difference regions in buffers A, B, and C.
+Buffers are not synchronized with their respective files, so changes done
+to these buffers are not saved at this point---the user can do this later,
+if necessary."
+  (interactive)
+  (let ((point-A (ediff-eval-in-buffer ediff-buffer-A (point)))
+	;;(point-B (ediff-eval-in-buffer ediff-buffer-B (point)))
+	(tmp-buffer (get-buffer-create ediff-tmp-buffer))
+	(buf-A-file-name
+	 (file-name-nondirectory (or (buffer-file-name ediff-buffer-A)
+				     (buffer-name ediff-buffer-A)
+				     )))
+	(buf-B-file-name
+	 (file-name-nondirectory (or (buffer-file-name ediff-buffer-B)
+				     (buffer-name ediff-buffer-B)
+				     )))
+	(buf-C-file-name
+	 (file-name-nondirectory (or (buffer-file-name ediff-buffer-C)
+				     ;; if (null ediff-buffer-C), there is
+				     ;; no danger, since we later check if
+				     ;; ediff-buffer-C is alive
+				     (buffer-name ediff-buffer-C)
+				     )))
+	(overl-A (ediff-get-value-according-to-buffer-type
+		  'A ediff-narrow-bounds))
+	(overl-B (ediff-get-value-according-to-buffer-type
+		  'B ediff-narrow-bounds))
+	(overl-C (ediff-get-value-according-to-buffer-type
+		  'C ediff-narrow-bounds))
+	beg-A end-A beg-B end-B beg-C end-C
+	file-A file-B file-C)
+    (ediff-unselect-and-select-difference -1)
+    
+    (setq beg-A (ediff-overlay-start overl-A)
+	  beg-B (ediff-overlay-start overl-B)
+	  beg-C (ediff-overlay-start overl-C)
+	  end-A (ediff-overlay-end overl-A)
+	  end-B (ediff-overlay-end overl-B)
+	  end-C (ediff-overlay-end overl-C))
+	  
+    (if ediff-word-mode
+	(progn
+	  (ediff-wordify beg-A end-A ediff-buffer-A tmp-buffer)
+	  (ediff-eval-in-buffer tmp-buffer
+	    (setq file-A (ediff-make-temp-file "regA")))
+	  (ediff-wordify beg-B end-B ediff-buffer-B tmp-buffer)
+	  (ediff-eval-in-buffer tmp-buffer
+	    (setq file-B (ediff-make-temp-file "regB")))
+	  (if ediff-3way-job
+	      (progn
+		(ediff-wordify beg-C end-C ediff-buffer-C tmp-buffer)
+		(ediff-eval-in-buffer tmp-buffer
+		  (setq file-C (ediff-make-temp-file "regC")))))
+	  )
+      ;; not word-mode
+      (ediff-eval-in-buffer ediff-buffer-A
+	(setq file-A (ediff-make-temp-file buf-A-file-name)))
+      (ediff-eval-in-buffer ediff-buffer-B
+	(setq file-B (ediff-make-temp-file buf-B-file-name)))
+      (if ediff-3way-job
+	  (ediff-eval-in-buffer ediff-buffer-C
+	    (setq file-C (ediff-make-temp-file buf-C-file-name))))
+      )
+	
+    (ediff-clear-diff-vector 'ediff-difference-vector-A 'fine-diffs-also)
+    (ediff-clear-diff-vector 'ediff-difference-vector-B 'fine-diffs-also)
+    (ediff-clear-diff-vector 'ediff-difference-vector-C 'fine-diffs-also)
+    (setq ediff-killed-diffs-alist nil) ; invalidate saved killed diff regions
+    
+    ;; In case of merge job, full it into thinking that it is just doing
+    ;; comparison
+    (let ((ediff-setup-diff-regions-function ediff-setup-diff-regions-function)
+	  (ediff-job-name ediff-job-name))
+      (if ediff-merge-job
+	  (setq ediff-setup-diff-regions-function 'ediff-setup-diff-regions3
+		ediff-job-name 'ediff-files3))
+      (funcall ediff-setup-diff-regions-function file-A file-B file-C))
+	    
+    (setq ediff-number-of-differences (length ediff-difference-vector-A))
+    (delete-file file-A)
+    (delete-file file-B)
+    (if file-C
+	(delete-file file-C))
+	
+    (if ediff-3way-job
+	(ediff-set-state-of-all-diffs-in-all-buffers ediff-control-buffer))
+	
+    (ediff-jump-to-difference (ediff-diff-at-point 'A point-A))
+    (message "")
+    ))
+    
+;; Not bound to any key---to dangerous. A user can do it if necessary.
+(defun ediff-revert-buffers-then-recompute-diffs (noconfirm)
+  "Revert buffers A, B and C. Then rerun Ediff on file A and file B."
+  (interactive "P")
+  (let ((bufA ediff-buffer-A)
+	(bufB ediff-buffer-B)
+	(bufC ediff-buffer-C)
+	(ctl-buf ediff-control-buffer)
+	(ancestor-buf ediff-ancestor-buffer)
+	(ancestor-job ediff-merge-with-ancestor-job)
+	(merge ediff-merge-job)
+	(comparison ediff-3way-comparison-job))
+    (ediff-eval-in-buffer bufA
+      (revert-buffer t noconfirm))
+    (ediff-eval-in-buffer bufB
+      (revert-buffer t noconfirm))
+    ;; this should only be executed in a 3way comparison, not in merge
+    (if comparison
+	(ediff-eval-in-buffer bufC
+	  (revert-buffer t noconfirm)))
+    (if merge
+	(progn
+	  (set-buffer ctl-buf)
+	  (ediff-really-quit)
+	  (kill-buffer bufC)
+	  (if ancestor-job
+	      (ediff-merge-buffers-with-ancestor bufA bufB ancestor-buf)
+	    (ediff-merge-buffers bufA bufB)))
+      (ediff-update-diffs))))
+
+
+;; optional NO-REHIGHLIGHT says to not rehighlight buffers 
+(defun ediff-recenter (&optional no-rehighlight)
+  "Bring the highlighted region of all buffers being compared into view.
+Reestablish the default three-window display."
+  (interactive)
+  
+  ;; force all minibuffer to display ediff's messages.
+  ;; when xemacs implements minibufferless screens, this won't be necessary
+  (if ediff-xemacs-p (setq synchronize-minibuffers t))
+  
+  (setq ediff-disturbed-overlays nil) ; clear after use
+  (let (buffer-read-only)
+    (if (and (ediff-buffer-live-p ediff-buffer-A)
+	     (ediff-buffer-live-p ediff-buffer-B)
+	     (or (not ediff-3way-job)
+		 (ediff-buffer-live-p ediff-buffer-C))
+	     )
+	(ediff-setup-windows
+	 ediff-buffer-A ediff-buffer-B ediff-buffer-C ediff-control-buffer)
+      (or (eq this-command 'ediff-quit)
+	  (message
+	   "You've killed an essential Ediff buffer---Please quit Ediff"
+	   (beep 1)))
+      ))
+      
+  ;; set visibility range appropriate to this invocation of Ediff.
+  (ediff-visible-region)
+  
+  ;; raise
+  (if (and window-system
+	   (symbolp this-command)
+	   (symbolp last-command)
+	   ;; Either one of the display-changing commands
+	   (or (memq this-command
+		     '(ediff-recenter
+		       ediff-toggle-wide-display ediff-toggle-multiframe))
+	       ;; Or one of the movement cmds and prev cmd was an Ediff cmd
+	       ;; This avoids rasing frames unnecessarily.
+	       (and (memq this-command
+			  '(ediff-next-difference
+			    ediff-previous-difference
+			    ediff-jump-to-difference
+			    ediff-jump-to-difference-at-point))
+		    (not (string-match "^ediff-" (symbol-name last-command)))
+		    )))
+      (progn
+	(if (window-live-p ediff-window-A)
+	    (ediff-raise-frame (ediff-window-frame ediff-window-A)))
+	(if (window-live-p ediff-window-B)
+	    (ediff-raise-frame (ediff-window-frame ediff-window-B)))
+	(if (window-live-p ediff-window-C)
+	    (ediff-raise-frame (ediff-window-frame ediff-window-C)))))
+  (if (and window-system
+	   (ediff-frame-live-p ediff-control-frame)
+	   (not (ediff-frame-iconified-p ediff-control-frame)))
+      (ediff-raise-frame ediff-control-frame))
+  
+  ;; Redisplay whatever buffers are showing, if there is a selected difference
+  (let* ((control-frame ediff-control-frame)
+	 (control-buf ediff-control-buffer))
+    (if (and (ediff-buffer-live-p ediff-buffer-A)
+	     (ediff-buffer-live-p ediff-buffer-B)
+	     (or (not ediff-3way-job)
+		 (ediff-buffer-live-p ediff-buffer-C))
+	     (ediff-valid-difference-p))
+	(progn
+	  (or no-rehighlight
+	      (ediff-operate-on-flags 'insert))
+	    
+	  (ediff-recenter-one-window 'A)
+	  (ediff-recenter-one-window 'B)
+	  (if ediff-3way-job
+	      (ediff-recenter-one-window 'C))
+	  
+	  (if (and (ediff-multiframe-setup-p)
+		   (not (ediff-frame-iconified-p ediff-control-frame)))
+	      (progn
+		(set-mouse-position control-frame 1 0)
+		(if (ediff-check-version '< 19 11 'xemacs) (sit-for 0))
+		(or ediff-xemacs-p
+		    (cond ((eq window-system 'ns)
+			   (unfocus-frame (selected-frame)))
+			  (t (unfocus-frame))))
+		))
+	  ))
+    (ediff-eval-in-buffer control-buf
+      (ediff-refresh-mode-lines))
+    ))
+  
+;; this function returns to the window it was called from
+;; (which was the control window)
+(defun ediff-recenter-one-window (buf-type)
+  (let* (;; context must be saved before switching to windows A/B/C
+	 (ctl-wind (selected-window))
+	 (shift (ediff-overlay-start
+		 (ediff-get-value-according-to-buffer-type 
+		  buf-type ediff-narrow-bounds)))
+	 (job-name ediff-job-name)
+	 (control-buf ediff-control-buffer)
+	 (before-flag-shift
+	  (if (eq ediff-highlighting-style 'ascii)
+	      (1- (length
+		   (symbol-value
+		    (intern (format "ediff-before-flag-%S" buf-type)))))
+	    0))
+	 (after-flag-shift
+	  (if (eq ediff-highlighting-style 'ascii)
+	      (1- (length
+		   (symbol-value
+		    (intern (format "ediff-after-flag-%S" buf-type)))))
+	    0))
+	 (window-name (intern (format "ediff-window-%S" buf-type)))
+	 (window (if (window-live-p (symbol-value window-name))
+		     (symbol-value window-name))))
+	 
+    (if (and window (eq job-name 'ediff-windows))
+	(set-window-start window 
+			  (- shift before-flag-shift)))
+    (if window
+	(progn
+	  (select-window window)
+	  (ediff-deactivate-mark)
+	  (ediff-position-region
+	   (- (ediff-get-diff-posn buf-type 'beg nil control-buf)
+	      before-flag-shift)
+	   (+ (ediff-get-diff-posn buf-type 'end nil control-buf)
+	      after-flag-shift)
+	   (ediff-get-diff-posn buf-type 'beg nil control-buf)
+	   job-name
+	   )))
+    (select-window ctl-wind)
+    ))
+
+	
+;; This will have to be refined for 3way jobs
+(defun ediff-toggle-split ()
+  "Toggle vertical/horizontal window split. 
+Does nothing if file-A and file-B are in different frames."
+  (interactive)
+  (let* ((wind-A (if (window-live-p ediff-window-A) ediff-window-A))
+	 (wind-B (if (window-live-p ediff-window-B) ediff-window-B))
+	 (wind-C (if (window-live-p ediff-window-C) ediff-window-C))
+	 (frame-A (if wind-A (ediff-window-frame wind-A)))
+	 (frame-B (if wind-B (ediff-window-frame wind-B)))
+	 (frame-C (if wind-C (ediff-window-frame wind-C))))
+    (if (or (eq frame-A frame-B)
+	    (not (ediff-frame-live-p frame-A))
+	    (not (ediff-frame-live-p frame-B))
+	    (if ediff-3way-comparison-job
+		(or (not (ediff-frame-live-p frame-C))
+		    (eq frame-A frame-C) (eq frame-B frame-C))))
+	(setq ediff-split-window-function
+	      (if (eq ediff-split-window-function 'split-window-vertically)
+		  'split-window-horizontally
+		'split-window-vertically))
+      (message "Buffers being compared are in different frames"))
+    (ediff-recenter 'no-rehighlight)))
+  
+(defun ediff-toggle-hilit ()
+  "Switch between highlighting using ASCII flags and highlighting using faces.
+On a dumb terminal, switches between ASCII highlighting and no highlighting." 
+  (interactive)
+  (if (not window-system)
+      (if (eq ediff-highlighting-style 'ascii)
+	  (progn
+	    (message "ASCII highlighting flags removed")
+	    (ediff-unselect-and-select-difference ediff-current-difference
+						  'unselect-only)
+	    (setq ediff-highlighting-style 'off))
+	(ediff-unselect-and-select-difference ediff-current-difference
+					      'select-only))
+    (ediff-unselect-and-select-difference ediff-current-difference
+					  'unselect-only)
+    ;; cycle through highlighting
+    (cond ((and ediff-use-faces ediff-highlight-all-diffs)
+	   (message "Unhighlighting unselected difference regions")
+	   (setq ediff-highlight-all-diffs nil))
+	  (ediff-use-faces
+	   (message "Highlighting with ASCII flags")
+	   (setq ediff-use-faces nil))
+	  (t
+	   (message "Re-highlighting all difference regions")
+	   (setq ediff-use-faces t
+		 ediff-highlight-all-diffs t)))
+		 
+    (if (and ediff-use-faces ediff-highlight-all-diffs)
+	(if (not (face-differs-from-default-p 'ediff-odd-diff-face-A-var))
+	    (progn
+	      (copy-face ediff-odd-diff-face-A 'ediff-odd-diff-face-A-var)
+	      (copy-face ediff-odd-diff-face-B 'ediff-odd-diff-face-B-var)
+	      (copy-face ediff-odd-diff-face-C 'ediff-odd-diff-face-C-var)
+	      (copy-face ediff-even-diff-face-A 'ediff-even-diff-face-A-var)
+	      (copy-face ediff-even-diff-face-B 'ediff-even-diff-face-B-var)
+	      (copy-face ediff-even-diff-face-C 'ediff-even-diff-face-C-var)
+	      ))
+      (copy-face 'default 'ediff-odd-diff-face-A-var)
+      (copy-face 'default 'ediff-odd-diff-face-B-var)
+      (copy-face 'default 'ediff-odd-diff-face-C-var)
+      (copy-face 'default 'ediff-even-diff-face-A-var)
+      (copy-face 'default 'ediff-even-diff-face-B-var)
+      (copy-face 'default 'ediff-even-diff-face-C-var))
+    
+    (ediff-unselect-and-select-difference
+     ediff-current-difference 'select-only))
+  (ediff-operate-on-flags 'insert)
+  )
+  
+(defun ediff-toggle-autorefine ()
+  "Toggle auto-refine mode."
+  (interactive)
+  (if ediff-word-mode
+      (error "No fine differences in this mode"))
+  (cond ((eq ediff-auto-refine 'nix)
+	 (setq ediff-auto-refine 'on)
+	 (ediff-make-fine-diffs ediff-current-difference 'noforce)
+	 (message "Auto-refining is ON"))
+	((eq ediff-auto-refine 'on)
+	 (message "Auto-refining is OFF")
+	 (setq ediff-auto-refine 'off))
+	(t ;; nix 'em
+	 (ediff-set-fine-diff-properties ediff-current-difference 'default)
+	 (message "Refinements are HIDDEN")
+	 (setq ediff-auto-refine 'nix))
+	))
+	
+(defun ediff-make-or-kill-fine-diffs (arg)
+  "Compute fine diffs. With negative prefix arg, kill fine diffs.
+In both cases, operates on the currrent difference region." 
+  (interactive "P")
+  (cond ((eq arg '-)
+	 (ediff-clear-fine-differences ediff-current-difference))
+	((and (numberp arg) (< arg 0))
+	 (ediff-clear-fine-differences ediff-current-difference))
+	(t (ediff-make-fine-diffs))))
+	 
+  
+(defun ediff-toggle-help ()
+  "Toggle short/long help message."
+  (interactive)
+  (let (buffer-read-only)
+    (erase-buffer)
+    (setq ediff-prefer-long-help-message (not ediff-prefer-long-help-message))
+    (ediff-set-help-message))
+  ;; remember the icon status of the control frame when the user requested
+  ;; full control message
+  (if (and ediff-prefer-long-help-message (ediff-multiframe-setup-p))
+      (setq ediff-prefer-iconified-control-frame
+	    (ediff-frame-iconified-p ediff-control-frame)))
+	    
+  (setq ediff-window-config-saved "") ; force redisplay
+  (ediff-recenter 'no-rehighlight))
+  
+  
+;; Optional argument, BUF, is passed only in a startup hook.
+(defun ediff-toggle-read-only (&optional buff)
+  "Toggles read-only in buffers being compared.
+If buffer is under version control and locked, check it out first."
+  (interactive)
+  
+  (or buff (ediff-recenter))
+  
+  ;; eval in buf A/B/C
+  (ediff-eval-in-buffer
+      (or buff (ediff-get-buffer (ediff-char-to-buftype last-command-char)))
+    (let* ((file (buffer-file-name (current-buffer)))
+	   (file-writable (and file (file-writable-p file)))
+	   (toggle-ro-cmd (cond (ediff-toggle-read-only-function)
+				(ediff-file-checked-out-flag 'toggle-read-only)
+				(file-writable 'toggle-read-only)
+				(t (key-binding "\C-x\C-q")))))
+      (if (and toggle-ro-cmd 
+	       (string-match "toggle-read-only" (symbol-name toggle-ro-cmd)))
+	  (save-excursion
+	    (save-window-excursion
+	      (setq ediff-file-checked-out-flag t)
+	      (command-execute toggle-ro-cmd)))
+	(error "Don't know how to toggle read-only in buffer %S"
+	       (current-buffer)))
+      ;; Check if we made the current buffer updatable, but its file is RO.
+      ;; Signal a warning in this case.
+      (if (and file (not buffer-read-only)
+	       (eq this-command 'ediff-toggle-read-only)
+	       (not file-writable))
+	  (message "Warning: file %s is read-only"
+		   (abbreviate-file-name file) (beep 1)))
+      )))
+      
+(defun ediff-swap-buffers ()
+  "Rotate the display of buffers A, B, and C."
+  (interactive)
+  (if (and (window-live-p ediff-window-A) (window-live-p ediff-window-B))
+      (let ((buf ediff-buffer-A)
+	    (values ediff-buffer-A-values-orig)
+	    (diff-vec ediff-difference-vector-A)
+	    (hide-regexp ediff-regexp-hide-A)
+	    (focus-regexp ediff-regexp-focus-A)
+	    (wide-visibility-p (eq ediff-visible-bounds ediff-wide-bounds))
+	    (overlay (if window-system ediff-current-diff-overlay-A))
+	    )
+	(if ediff-3way-comparison-job
+	    (progn
+	      (set-window-buffer ediff-window-A ediff-buffer-C)
+	      (set-window-buffer ediff-window-B ediff-buffer-A)
+	      (set-window-buffer ediff-window-C ediff-buffer-B)
+	      )
+	  (set-window-buffer ediff-window-A ediff-buffer-B)
+	  (set-window-buffer ediff-window-B ediff-buffer-A))
+	;; swap diff buffers
+	(if ediff-3way-comparison-job
+	    (setq ediff-buffer-A ediff-buffer-C
+		  ediff-buffer-C ediff-buffer-B
+		  ediff-buffer-B buf)
+	  (setq ediff-buffer-A ediff-buffer-B
+		ediff-buffer-B buf))
+		
+	;; swap saved buffer characteristics
+	(if ediff-3way-comparison-job
+	    (setq ediff-buffer-A-values-orig ediff-buffer-C-values-orig
+		  ediff-buffer-C-values-orig ediff-buffer-B-values-orig
+		  ediff-buffer-B-values-orig values)
+	  (setq ediff-buffer-A-values-orig ediff-buffer-B-values-orig
+		ediff-buffer-B-values-orig values))
+	
+	;; swap diff vectors
+	(if ediff-3way-comparison-job
+	    (setq ediff-difference-vector-A ediff-difference-vector-C
+		  ediff-difference-vector-C ediff-difference-vector-B
+		  ediff-difference-vector-B diff-vec)
+	  (setq ediff-difference-vector-A ediff-difference-vector-B
+		ediff-difference-vector-B diff-vec))
+		
+	;; swap hide/focus regexp
+	(if ediff-3way-comparison-job
+	    (setq ediff-regexp-hide-A ediff-regexp-hide-C
+		  ediff-regexp-hide-C ediff-regexp-hide-B
+		  ediff-regexp-hide-B hide-regexp
+		  ediff-regexp-focus-A ediff-regexp-focus-C
+		  ediff-regexp-focus-C ediff-regexp-focus-B
+		  ediff-regexp-focus-B focus-regexp)
+	  (setq ediff-regexp-hide-A ediff-regexp-hide-B
+		ediff-regexp-hide-B hide-regexp
+		ediff-regexp-focus-A ediff-regexp-focus-B
+		ediff-regexp-focus-B focus-regexp))
+	
+	;; The following is needed for XEmacs, since there one can't move
+	;; overlay to another buffer. In Emacs, this swap is redundant.
+	(if window-system
+	    (if ediff-3way-comparison-job
+		(setq ediff-current-diff-overlay-A ediff-current-diff-overlay-C
+		      ediff-current-diff-overlay-C ediff-current-diff-overlay-B
+		      ediff-current-diff-overlay-B overlay)
+	      (setq ediff-current-diff-overlay-A ediff-current-diff-overlay-B
+		    ediff-current-diff-overlay-B overlay)))
+		    
+	;; swap wide bounds
+	(setq ediff-wide-bounds
+	      (cond (ediff-3way-comparison-job
+		     (list (nth 2 ediff-wide-bounds)
+			   (nth 0 ediff-wide-bounds)
+			   (nth 1 ediff-wide-bounds)))
+		    (ediff-3way-job
+		     (list (nth 1 ediff-wide-bounds)
+			   (nth 0 ediff-wide-bounds)
+			   (nth 2 ediff-wide-bounds)))
+		    (t 
+		     (list (nth 1 ediff-wide-bounds)
+			   (nth 0 ediff-wide-bounds)))))
+	;; swap narrow bounds
+	(setq ediff-narrow-bounds
+	      (cond (ediff-3way-comparison-job
+		     (list (nth 2 ediff-narrow-bounds)
+			   (nth 0 ediff-narrow-bounds)
+			   (nth 1 ediff-narrow-bounds)))
+		    (ediff-3way-job
+		     (list (nth 1 ediff-narrow-bounds)
+			   (nth 0 ediff-narrow-bounds)
+			   (nth 2 ediff-narrow-bounds)))
+		    (t 
+		     (list (nth 1 ediff-narrow-bounds)
+			   (nth 0 ediff-narrow-bounds)))))
+	(if wide-visibility-p
+	    (setq ediff-visible-bounds ediff-wide-bounds)
+	  (setq ediff-visible-bounds ediff-narrow-bounds))
+	))
+  (if ediff-3way-job
+      (ediff-set-state-of-all-diffs-in-all-buffers ediff-control-buffer))
+  (ediff-recenter 'no-rehighlight)
+  )
+  
+
+(defun ediff-toggle-wide-display ()
+  "Toggle wide/regular display.
+This is especially useful when comparing buffers side-by-side."
+  (interactive)
+  (or window-system
+      (error "Emacs is not running as a window application"))
+  (ediff-recenter 'no-rehighlight) ; make sure buffs are displayed in windows
+  (let ((ctl-buf ediff-control-buffer))
+    (setq ediff-wide-display-p (not ediff-wide-display-p))
+    (if (not ediff-wide-display-p)
+	(ediff-eval-in-buffer ctl-buf
+	  (ediff-modify-frame-parameters
+	   ediff-wide-display-frame ediff-wide-display-orig-parameters)
+	  (sit-for (if ediff-xemacs-p 0.4 0))
+	  ;; restore control buf, since ctl window may have been deleted
+	  ;; during resizing
+	  (set-buffer ctl-buf)
+	  (setq ediff-wide-display-orig-parameters nil
+		ediff-window-B nil) ; force update of window config
+	  (ediff-recenter 'no-rehighlight))
+      (funcall ediff-make-wide-display-function)
+      (sit-for (if ediff-xemacs-p 0.4 0))
+      (ediff-eval-in-buffer ctl-buf
+	(setq ediff-window-B nil) ; force update of window config
+	(ediff-recenter 'no-rehighlight)))))
+	
+(defun ediff-toggle-multiframe ()
+  "Switch from the multiframe display to single-frame display and back.
+This is primarily for debugging, but one can use it for fun, too."
+  (interactive)
+  (if (ediff-check-version '< 19 12 'xemacs)
+      (error "This command doesn't work under XEmacs 19.11 and earlier"))
+  (or window-system
+      (error "Emacs is not running as a window application"))
+  (cond ((eq ediff-window-setup-function 'ediff-setup-windows-multiframe)
+	 (setq ediff-window-setup-function 'ediff-setup-windows-plain))
+	((eq ediff-window-setup-function 'ediff-setup-windows-plain)
+	 (setq ediff-window-setup-function 'ediff-setup-windows-multiframe)))
+  (setq ediff-window-B nil)
+  (ediff-recenter 'no-rehighlight))
+	       
+;; Merging
+
+(defun ediff-toggle-show-clashes-only ()
+  "Toggle the mode where only the regions where both buffers differ with the ancestor are shown."
+  (interactive)
+  (if (not ediff-merge-with-ancestor-job)
+      (error "This command makes sense only when merging with an ancestor"))
+  (setq ediff-show-clashes-only (not ediff-show-clashes-only))
+  (if ediff-show-clashes-only
+      (message "Focus on regions where both buffers differ from the ancestor")
+    (message "Canceling focus on regions where changes clash")))
+	       
+;; Widening/narrowing
+
+(defun ediff-toggle-narrow-region ()
+  "Toggle narrowing in buffers A, B, and C.
+Used in ediff-windows/regions only."
+  (interactive)
+  (if (eq ediff-buffer-A ediff-buffer-B)
+      (error
+       "Buffers A and B are the same. Can't narrow to two different regions"))
+  (if (eq ediff-visible-bounds ediff-wide-bounds)
+      (setq ediff-visible-bounds ediff-narrow-bounds)
+    (setq ediff-visible-bounds ediff-wide-bounds))
+  (ediff-recenter 'no-rehighlight))
+  
+;; Narrow bufs A/B/C to ediff-visible-bounds. If this is currently set to
+;; ediff-wide-bounds, then this actually widens.
+;; This function does nothing if job-name is not ediff-small/large-regions or
+;; ediff-windows. 
+;; Does nothing if buffer-A  = buffer-B since we can't narrow
+;; to two different regions in one buffer.
+(defun ediff-visible-region ()
+  (if (or (eq ediff-buffer-A ediff-buffer-B)
+	  (eq ediff-buffer-A ediff-buffer-C)
+	  (eq ediff-buffer-C ediff-buffer-B))
+      ()
+    ;; If ediff-*-regions/windows, ediff-visible-bounds is already set
+    ;; Otherwise, always use full range.
+    (if (not ediff-word-mode-job)
+	(setq ediff-visible-bounds ediff-wide-bounds))
+    (let ((overl-A (ediff-get-value-according-to-buffer-type
+		    'A  ediff-visible-bounds))
+	  (overl-B (ediff-get-value-according-to-buffer-type
+		    'B  ediff-visible-bounds))
+	  (overl-C (ediff-get-value-according-to-buffer-type
+		    'C  ediff-visible-bounds))
+	  )
+      (ediff-eval-in-buffer ediff-buffer-A
+	(narrow-to-region
+	 (ediff-overlay-start overl-A) (ediff-overlay-end overl-A)))
+      (ediff-eval-in-buffer ediff-buffer-B
+	(narrow-to-region
+	 (ediff-overlay-start overl-B) (ediff-overlay-end overl-B)))
+      
+      (if ediff-3way-job
+	  (ediff-eval-in-buffer ediff-buffer-C
+	    (narrow-to-region
+	     (ediff-overlay-start overl-C) (ediff-overlay-end overl-C))))
+      )))
+  
+
+;; Window scrolling operations
+
+;; Performs some operation on the two file windows (if they are showing).
+;; Traps all errors on the operation in windows A/B/C.
+;; Usually, errors come from scrolling off the
+;; beginning or end of the buffer, and this gives error messages.
+(defun ediff-operate-on-windows (operation arg)
+	 
+  ;; make sure windows aren't dead
+  (if (not (and (window-live-p ediff-window-A) (window-live-p ediff-window-B)))
+      (ediff-recenter 'no-rehighlight))
+  (if (not (and (ediff-buffer-live-p ediff-buffer-A)
+		(ediff-buffer-live-p ediff-buffer-B)
+		(or (not ediff-3way-job) ediff-buffer-C)
+		))
+      (error "You've killed an essential Ediff buffer---Please quit Ediff"))
+	
+  (let* ((wind (selected-window))
+	 (wind-A ediff-window-A)
+	 (wind-B ediff-window-B)
+	 (wind-C ediff-window-C)
+	 (three-way ediff-3way-job))
+	     
+    (select-window wind-A)
+    (condition-case nil
+	(funcall operation arg)
+      (error))
+    (select-window wind-B)
+    (condition-case nil
+	(funcall operation arg)
+      (error))
+    (if three-way
+	(progn
+	  (select-window wind-C)
+	  (condition-case nil
+	      (funcall operation arg)
+	    (error))))
+    
+    (select-window wind)))
+
+(defun ediff-scroll-vertically (&optional arg)
+  "Vertically scroll buffers A, B \(and C if appropriate\).
+With optional argument ARG, scroll ARG lines; otherwise scroll by nearly
+the height of window-A."
+  (interactive "P")
+  
+  ;; make sure windows aren't dead
+  (if (not (and (window-live-p ediff-window-A) (window-live-p ediff-window-B)))
+      (ediff-recenter 'no-rehighlight))
+  (if (not (and (ediff-buffer-live-p ediff-buffer-A)
+		(ediff-buffer-live-p ediff-buffer-B)
+		(or (not ediff-3way-job)
+		    (ediff-buffer-live-p ediff-buffer-C))
+		))
+      (error "You've killed an essential Ediff buffer---Please quit Ediff"))
+      
+  (ediff-operate-on-windows
+   (if (memq last-command-char '(?v ?\C-v))
+       'scroll-up 
+     'scroll-down)
+   ;; calculate argument to scroll-up/down
+   ;; if there is an explicit argument
+   (if (and arg (not (equal arg '-)))
+       ;; use it
+       (prefix-numeric-value arg)
+     ;; if not, see if we can determine a default amount (the window height)
+     (let* (default-amount)
+       (setq default-amount 
+	     (- (min (window-height ediff-window-A)
+		     (window-height ediff-window-B)
+		     (if ediff-3way-job
+			 (window-height ediff-window-C)
+		       123) ; some large number
+		     )
+		1 next-screen-context-lines))
+       ;; window found
+       (if arg
+	   ;; C-u as argument means half of default amount
+	   (/ default-amount 2)
+	 ;; no argument means default amount
+	 default-amount)))))
+
+
+(defun ediff-scroll-horizontally (&optional arg)
+  "Horizontally scroll buffers A, B \(and C if appropriate\).
+If an argument is given, that is how many columns are scrolled, else nearly
+the width of the A/B/C windows."
+  (interactive "P")
+  
+  ;; make sure windows aren't dead
+  (if (not (and (window-live-p ediff-window-A) (window-live-p ediff-window-B)))
+      (ediff-recenter 'no-rehighlight))
+  (if (not (and (ediff-buffer-live-p ediff-buffer-A)
+		(ediff-buffer-live-p ediff-buffer-B)
+		(or (not ediff-3way-job)
+		    (ediff-buffer-live-p ediff-buffer-C))
+		))
+      (error "You've killed an essential Ediff buffer---Please quit Ediff"))
+    
+  (ediff-operate-on-windows
+   (if (= last-command-char ?<)
+       'scroll-left
+     'scroll-right)
+   ;; calculate argument to scroll-left/right
+   ;; if there is an explicit argument
+   (if (and arg (not (equal arg '-)))
+       ;; use it
+       (prefix-numeric-value arg)
+     ;; if not, see if we can determine a default amount
+     ;; (half the window width)
+     (if (null ediff-control-window)
+	 ;; no control window, use nil
+	 nil
+       (let ((default-amount
+	       (- (/ (min (window-width ediff-window-A)
+			  (window-width ediff-window-B)
+			  (if ediff-3way-comparison-job
+			      (window-width ediff-window-C)
+			    500) ; some large number
+			  )
+		     2)
+		  3)))
+	 ;; window found
+	 (if arg
+	     ;; C-u as argument means half of default amount
+	     (/ default-amount 2)
+	   ;; no argument means default amount
+	   default-amount))))))
+
+
+;;BEG, END show the region to be positioned.
+;;JOB-NAME holds ediff-job-name. Ediff-windows job positions regions
+;;differently. 
+(defun ediff-position-region (beg end pos job-name)
+  (if (> end (point-max))
+      (setq end (point-max)))
+  (if (eq job-name 'ediff-windows)
+      (if (pos-visible-in-window-p end)
+	  () ; do nothing, wind is already positioned
+	;; at this point, windows are positioned at the beginning of the
+	;; file regions (not diff-regions)  being compared.
+	(save-excursion
+	  (move-to-window-line (- (window-height) 2))
+	  (let ((amount (+ 2 (count-lines (point) end))))
+	    (scroll-up amount))))
+    (set-window-start (selected-window) beg)
+    (if (pos-visible-in-window-p end)
+	;; Determine the number of lines that the region occupies
+	(let ((lines 0))
+	  (while (> end (progn
+			  (move-to-window-line lines)
+			  (point)))
+	    (setq lines (1+ lines)))
+	  ;; And position the beginning on the right line
+	  (goto-char beg)
+	  (recenter (/ (1+ (max (- (1- (window-height (selected-window)))
+				   lines)
+				1)
+			   )
+		       2))))
+    (goto-char pos)
+    ))
+
+
+(defun ediff-next-difference (&optional arg)
+  "Advance to the next difference. 
+With a prefix argument, go back that many differences."
+  (interactive "P")
+  (if (< ediff-current-difference ediff-number-of-differences)
+      (let ((n (min ediff-number-of-differences
+		    (+ ediff-current-difference (if arg arg 1))))
+	    regexp-skip buffer-read-only)
+	    
+	(or (>= n ediff-number-of-differences)
+	    (setq regexp-skip (funcall ediff-skip-diff-region-function n))
+	    (ediff-install-fine-diff-if-necessary n))
+	(while (and (< n ediff-number-of-differences)
+		    (or
+		     ;; regexp skip
+		     regexp-skip
+		     ;; skip clashes, if necessary
+		     (and ediff-show-clashes-only
+			  (string-match "prefer"
+					(or (ediff-get-state-of-merge n) "")))
+		     ;; skip difference regions that differ in white space
+		     (and ediff-ignore-similar-regions
+			  (ediff-no-fine-diffs-p n))))
+	  (setq n (1+ n))
+	  (if (= 0 (mod n 20))
+	      (message "Skipped over region %d and counting ..."  n))
+	  (or (>= n ediff-number-of-differences)
+	      (setq regexp-skip (funcall ediff-skip-diff-region-function n))
+	      (ediff-install-fine-diff-if-necessary n))
+	  )
+	
+	(ediff-unselect-and-select-difference n)
+	) ; let
+    (ediff-visible-region)
+    (error "At end of the difference list")))
+
+(defun ediff-previous-difference (&optional arg)
+  "Go to the previous difference. 
+With a prefix argument, go back that many differences."
+  (interactive "P")
+  (if (> ediff-current-difference -1)
+      (let ((n (max -1 (- ediff-current-difference (if arg arg 1))))
+	    regexp-skip buffer-read-only)
+	    
+	(or (< n 0)
+	    (setq regexp-skip (funcall ediff-skip-diff-region-function n))
+	    (ediff-install-fine-diff-if-necessary n))
+	(while (and (> n -1)
+		    (or
+		     ;; regexp skip
+		     regexp-skip
+		     ;; skip clashes, if necessary
+		     (and ediff-show-clashes-only
+			  (string-match "prefer"
+					(or (ediff-get-state-of-merge n) "")))
+		     ;; skip difference regions that differ in white space
+		     (and ediff-ignore-similar-regions
+			  (ediff-no-fine-diffs-p n))))
+	  (if (= 0 (mod (1+ n) 20))
+	      (message "Skipped over region %d and counting ..."  (1+ n)))
+	  (setq n (1- n))
+	  (or (< n 0)
+	      (setq regexp-skip (funcall ediff-skip-diff-region-function n))
+	      (ediff-install-fine-diff-if-necessary n))
+	  )
+	(ediff-unselect-and-select-difference n)
+	) ; let
+    (ediff-visible-region)
+    (error "At beginning of the difference list")))
+
+(defun ediff-jump-to-difference (difference-number)
+  "Go to the difference specified as a prefix argument."
+  (interactive "p")
+  (let (buffer-read-only)
+    (setq difference-number (1- difference-number))
+    (if (and (>= difference-number -1)
+	     (< difference-number (1+ ediff-number-of-differences)))
+	(ediff-unselect-and-select-difference difference-number)
+      (error "Bad difference number, %d" difference-number))))
+      
+(defun ediff-jump-to-difference-at-point ()
+  "Go to difference closest to the point in buffer A, B, or C.
+The type of buffer depends on last command character \(a, b, or c\) that
+invoked this command."
+  (interactive)
+  (let ((buf-type (ediff-char-to-buftype last-command-char))
+	buffer-read-only)
+    (ediff-jump-to-difference (ediff-diff-at-point buf-type))))
+	
+      
+;; find region most related to the current point position (or POS, if given)
+(defun ediff-diff-at-point (buf-type &optional pos)
+  (let ((buffer (ediff-get-buffer buf-type))
+	(ctl-buffer ediff-control-buffer)
+	(max-dif-num (1- ediff-number-of-differences))
+	(diff-no -1)
+	(prev-beg 0)
+	(prev-end 0)
+	(beg 0)
+	(end 0))
+	
+    (ediff-eval-in-buffer buffer
+      (setq pos (or pos (point)))
+      (while (and (or (< pos prev-beg) (> pos beg))
+		  (< diff-no max-dif-num))
+	(setq diff-no (1+ diff-no))
+	(setq prev-beg beg
+	      prev-end end)
+	(setq beg (ediff-get-diff-posn buf-type 'beg diff-no ctl-buffer)
+	      end (ediff-get-diff-posn buf-type 'end diff-no ctl-buffer))
+	)
+      
+     (if (< (abs (- pos prev-end))
+	    (abs (- pos beg)))
+	 diff-no
+       (1+ diff-no)) ; jump-to-diff works with diff nums higher by 1
+     )))
+
+
+;;; Copying diffs.
+
+(defun ediff-diff-to-diff (arg &optional keys)
+  "Copy buffer-X'th diff to buffer Y \(X,Y are A, B, or C\).
+If numerical prefix argument, copy this diff specified in the arg.
+Otherwise, copy the difference given by `ediff-current-difference'.
+This command assumes it is bound to a 2-character key sequence, `ab', `ba',
+`ac', etc., which is used to determine the types of buffers to be used for
+copying difference regions. The first character in the sequence specifies
+the source buffer and the second specifies the target.
+
+If the second optional argument, a 2-character string, is given, use it to
+determine the source and the target buffers instead of the command keys."
+  (interactive "P")
+  (or keys (setq keys (this-command-keys)))
+  (if arg
+      (ediff-jump-to-difference arg))
+  (let* ((key1 (aref keys 0))
+	 (key2 (aref keys 1))
+	 (char1 (if (and ediff-xemacs-p (eventp key1)) (event-key key1) key1))
+	 (char2 (if (and ediff-xemacs-p (eventp key1)) (event-key key2) key2)))
+    (ediff-copy-diff ediff-current-difference
+		     (ediff-char-to-buftype char1)
+		     (ediff-char-to-buftype char2))
+    (ediff-recenter 'no-rehighlight)))
+
+
+;; Copy diff N from FROM-BUF-TYPE \(given as A, B or C\) to TO-BUF-TYPE.
+;; If optional DO-NOT-SAVE is non-nil, do not save the old value of the
+;; target diff. This is used in merging, when constructing the merged
+;; version.
+(defun ediff-copy-diff (n from-buf-type to-buf-type
+			  &optional batch-invocation reg-to-copy)
+  (let* ((to-buf (ediff-get-buffer to-buf-type))
+	 ;;(from-buf (if (not reg-to-copy) (ediff-get-buffer from-buf-type)))
+	 (ctrl-buf ediff-control-buffer)
+	 (saved-p t)
+	 (three-way ediff-3way-job)
+	 messg
+	 ediff-verbose-p
+	 reg-to-delete reg-to-delete-beg reg-to-delete-end)
+	
+    (ediff-operate-on-flags 'remove)
+    (setq reg-to-delete-beg
+	  (ediff-get-diff-posn to-buf-type 'beg n ctrl-buf))
+    (setq reg-to-delete-end
+	  (ediff-get-diff-posn to-buf-type 'end n ctrl-buf))
+	  
+    (if reg-to-copy
+	(setq from-buf-type nil)
+      (setq reg-to-copy (ediff-get-region-contents n from-buf-type ctrl-buf)))
+    
+    (setq reg-to-delete (ediff-get-region-contents
+			 n to-buf-type ctrl-buf
+			 reg-to-delete-beg reg-to-delete-end))
+    
+    (setq ediff-disturbed-overlays nil) ; clear before use
+    
+    (if (string= reg-to-delete reg-to-copy)
+	(setq saved-p nil)     ; refuse to copy identical buffers
+;;;	(progn ; refuse to copy identical buffers
+;;;	  (setq saved-p nil)
+;;;	  (or batch-invocation
+;;;	      (message
+;;;	       "Region %d in buffer %S is identical to that in buffer %S"
+;;;	       (1+ n) from-buf-type to-buf-type (ding))))
+      ;; seems ok to copy
+      (if (or batch-invocation (ediff-test-save-region n to-buf-type))
+	  (condition-case conds
+	      (progn
+		(ediff-eval-in-buffer to-buf
+		  ;; to prevent flags from interfering if buffer is writable
+		  (let ((inhibit-read-only (null buffer-read-only))
+			before-change-function)
+		    ;; these two insert a dummy char to overcome a bug in
+		    ;; XEmacs, which sometimes prevents 0-length extents
+		    ;; from sensing insertion at its end-points.
+		    (if ediff-xemacs-p
+			(progn
+			  (goto-char reg-to-delete-end)
+			  (insert-before-markers "@")))
+		    
+		    (goto-char reg-to-delete-end)
+		    (insert-before-markers reg-to-copy)
+		    
+		    ;; delete the dummy char "@"
+		    (if ediff-xemacs-p
+			(delete-char 1))
+		    
+		    (if ediff-xemacs-p
+			(progn
+			  (ediff-collect-extents-xemacs reg-to-delete-beg)
+			  (if (> reg-to-delete-end reg-to-delete-beg)
+			      (progn
+				(kill-region reg-to-delete-beg
+					     reg-to-delete-end) 
+				(if (string= reg-to-copy "")
+				    (ediff-adjust-disturbed-extents-xemacs
+				     reg-to-delete-beg)))))
+		      (if (> reg-to-delete-end reg-to-delete-beg)
+			  (kill-region reg-to-delete-beg reg-to-delete-end)
+			(ediff-move-disturbed-overlays reg-to-delete-beg)
+			))
+		    ))
+		(or batch-invocation
+		    (setq 
+		     messg
+		     (ediff-save-diff-region n to-buf-type reg-to-delete))))
+	    (error (message "ediff-copy-diff: %s %s"
+			    (car conds)
+			    (mapconcat 'prin1-to-string (cdr conds) " "))
+		   (beep 1)
+		   (sit-for 2)
+		   (setq saved-p nil)
+		   )))
+      )
+    
+    ;; adjust state of difference in case 3-way and diff was copied ok
+    (if (and saved-p three-way)
+	(ediff-set-state-of-all-diffs-in-all-buffers ctrl-buf))
+
+    (if batch-invocation
+	(ediff-clear-fine-differences n)
+      ;; If diff3 job, we should recompute fine diffs so we clear them
+      ;; before reinserting flags (and thus before ediff-recenter).
+      (if (and saved-p three-way)
+	  (ediff-clear-fine-differences n))
+      (ediff-operate-on-flags 'insert)
+      ;; For diff2 jobs, don't recompute fine diffs, since we know there
+      ;; aren't any. So we clear diffs after ediff-recenter.
+      (if (and saved-p (not three-way))
+	  (ediff-clear-fine-differences n))
+      ;; Make sure that the message about saving and how to restore is seen
+      ;; by the user
+      (message messg))
+    ))
+     
+;; Save Nth diff of buffer BUF-TYPE \(A, B, or C\).
+;; That is to say, the Nth diff on the `ediff-killed-diffs-alist'.  REG
+;; is the region to save.  It is redundant here, but is passed anyway, for
+;; convenience.
+(defun ediff-save-diff-region (n buf-type reg)
+  (let* ((n-th-diff-saved (assoc n ediff-killed-diffs-alist))
+	 (buf (ediff-get-buffer buf-type))
+	 (this-buf-n-th-diff-saved (assoc buf (cdr n-th-diff-saved))))
+	 
+    (if this-buf-n-th-diff-saved
+	;; either nothing saved for n-th diff and buffer or we OK'ed
+	;; overriding
+	(setcdr this-buf-n-th-diff-saved reg)
+      (if n-th-diff-saved ;; n-th diff saved, but for another buffer
+	  (nconc n-th-diff-saved  (list (cons buf reg)))
+	(setq ediff-killed-diffs-alist  ;; create record for n-th diff
+	      (cons (list n (cons buf reg))
+		    ediff-killed-diffs-alist))))
+    (message "Saving old diff region #%d of buffer %S. To recover, type `r%s'"
+	     (1+ n) buf-type
+	     (if ediff-merge-job
+		 "" (downcase (symbol-name buf-type))))
+    ))
+    
+;; Test if saving Nth difference region of buffer BUF-TYPE is possible.
+(defun ediff-test-save-region (n buf-type)
+  (let* ((n-th-diff-saved (assoc n ediff-killed-diffs-alist))
+	 (buf (ediff-get-buffer buf-type))
+	 (this-buf-n-th-diff-saved (assoc buf (cdr n-th-diff-saved))))
+	 
+    (if this-buf-n-th-diff-saved
+	(if (yes-or-no-p
+	     (format 
+	      "You've previously copied diff region %d to buffer %S. Confirm "
+	      (1+ n) buf-type))
+	    t
+	  (error "Quit"))
+      t)))
+	  
+(defun ediff-pop-diff (n buf-type)
+  "Pop last killed Nth diff region from buffer BUF-TYPE."
+  (let* ((n-th-record (assoc n ediff-killed-diffs-alist))
+	 (buf (ediff-get-buffer buf-type))
+	 (saved-rec (assoc buf (cdr n-th-record)))
+	 (three-way ediff-3way-job)
+	 (ctl-buf ediff-control-buffer)
+	 ediff-verbose-p
+	 saved-diff reg-beg reg-end recovered)
+	
+    (if (cdr saved-rec)
+	(setq saved-diff (cdr saved-rec))
+      (if (> ediff-number-of-differences 0)
+	  (error "Nothing saved for diff %d in buffer %S" (1+ n) buf-type)
+	(error "No differences found")))
+    
+    (ediff-operate-on-flags 'remove)
+	
+    (setq reg-beg (ediff-get-diff-posn buf-type 'beg n ediff-control-buffer))
+    (setq reg-end (ediff-get-diff-posn buf-type 'end n ediff-control-buffer))
+    (setq ediff-disturbed-overlays nil) ; clear before use
+    
+    (condition-case conds
+	(ediff-eval-in-buffer buf
+	  (let ((inhibit-read-only (null buffer-read-only))
+		(before-change-function nil))
+	    ;; these two insert a dummy char to overcome a bug in XEmacs,
+	    ;; which sometimes prevents 0-length extents from sensing
+	    ;; insertion at its end-points.
+	    (if ediff-xemacs-p
+		(progn
+		  (goto-char reg-end)
+		  (insert-before-markers "@")))
+	    
+	    (goto-char reg-end)
+	    (insert-before-markers saved-diff)
+	    
+	    ;; delete dummy char
+	    (if ediff-xemacs-p
+		(delete-char 1))
+	    
+	    (if ediff-xemacs-p
+		(progn
+		  (ediff-collect-extents-xemacs reg-beg)
+		  (if (> reg-end reg-beg)
+		      (progn
+			(kill-region reg-beg reg-end)
+			(if (string= saved-diff "")
+			    (ediff-adjust-disturbed-extents-xemacs reg-beg)))))
+	      (if (> reg-end reg-beg)
+		  (kill-region reg-beg reg-end)
+		(ediff-move-disturbed-overlays reg-beg)
+		))
+	    
+	    (setq recovered t)
+	    ))
+      (error (message "ediff-pop-diff: %s %s"
+		      (car conds)
+		      (mapconcat 'prin1-to-string (cdr conds) " "))
+	     (beep 1)))
+    
+    ;; Clearing fine diffs is necessary in order for ediff-operate-on-flags
+    ;; to properly recompute them. We can't rely on ediff-copy-diff on
+    ;; clearing this vector because the user might have modified diff
+    ;; regions after copying and may have recomputed fine diffs.
+    (if recovered
+	(ediff-clear-fine-differences n))
+	  
+    ;; adjust state of difference
+    (if (and three-way recovered)
+	(ediff-set-state-of-diff-in-all-buffers n ctl-buf))
+	
+    (ediff-operate-on-flags 'insert)
+    (if recovered
+	(progn
+	  (setq n-th-record (delq saved-rec n-th-record))
+	  (message "Diff region %d in buffer %S restored" (1+ n) buf-type)
+	  ))
+    ))
+      
+(defun ediff-restore-diff  (arg &optional key)
+  "Restore ARGth diff from `ediff-killed-diffs-alist'.
+ARG is a prefix argument.  If ARG is nil, restore current-difference.
+
+If the second optional argument, a character, is given, use it to
+determine the target buffer instead of last-command-char"
+  (interactive "P")
+  (if arg
+      (ediff-jump-to-difference arg))
+  (ediff-pop-diff ediff-current-difference 
+		  (ediff-char-to-buftype (or key last-command-char)))
+  (ediff-recenter 'no-rehighlight))
+  
+(defun ediff-toggle-regexp-match ()
+  "Toggle between focusing and hiding of difference regions that match
+a regular expression typed in by the user."
+  (interactive)
+  (let ((regexp-A "")
+	(regexp-B "")
+	(regexp-C "")
+	msg-connective alt-msg-connective alt-connective)
+    (cond
+     ((or (and (eq ediff-skip-diff-region-function
+		   'ediff-focus-on-regexp-matches)
+	       (eq last-command-char ?f))
+	  (and (eq ediff-skip-diff-region-function 'ediff-hide-regexp-matches)
+	       (eq last-command-char ?h)))
+      (message "Selective browsing by regexp turned off")
+      (setq ediff-skip-diff-region-function 'ediff-show-all-diffs))
+     ((eq last-command-char ?h)
+      (setq ediff-skip-diff-region-function 'ediff-hide-regexp-matches
+	    regexp-A 
+	    (read-string
+	     (format 
+	      "Ignore A-regions matching this regexp (default \"%s\"): "
+	      ediff-regexp-hide-A))
+	    regexp-B
+	    (read-string
+	     (format 
+	      "Ignore B-regions matching this regexp (default \"%s\"): "
+	      ediff-regexp-hide-B)))
+      (if ediff-3way-comparison-job
+	  (setq regexp-C
+		(read-string
+		 (format 
+		  "Ignore C-regions matching this regexp (default \"%s\"): "
+		  ediff-regexp-hide-C))))
+      (if (eq ediff-hide-regexp-connective 'and)
+	  (setq msg-connective "BOTH"
+		alt-msg-connective "ONE OF"
+		alt-connective 'or)
+	(setq msg-connective "ONE OF"
+	      alt-msg-connective "BOTH"
+	      alt-connective 'and))
+      (if (y-or-n-p
+	   (format
+	    "Hiding diff regions that match %s regexps. Use %s instead? "
+	    msg-connective alt-msg-connective))
+	  (progn
+	    (setq ediff-hide-regexp-connective alt-connective)
+	    (message "Hiding diff regions that match %s regexps"
+		     alt-msg-connective))
+	(message "Hiding diff regions that match %s regexps" msg-connective))
+      (or (string= regexp-A "") (setq ediff-regexp-hide-A regexp-A))
+      (or (string= regexp-B "") (setq ediff-regexp-hide-B regexp-B))
+      (or (string= regexp-C "") (setq ediff-regexp-hide-C regexp-C)))
+     ((eq last-command-char ?f)
+      (setq ediff-skip-diff-region-function 'ediff-focus-on-regexp-matches
+	    regexp-A 
+	    (read-string
+	     (format 
+	      "Focus on A-regions matching this regexp (default \"%s\"): "
+	      ediff-regexp-focus-A))
+	    regexp-B
+	    (read-string
+	     (format 
+	      "Focus on B-regions matching this regexp (default \"%s\"): "
+	      ediff-regexp-focus-B)))
+      (if ediff-3way-comparison-job
+	  (setq regexp-C
+		(read-string
+		 (format 
+		  "Focus on C-regions matching this regexp (default \"%s\"): "
+		  ediff-regexp-focus-C))))
+      (if (eq ediff-focus-regexp-connective 'and)
+	  (setq msg-connective "BOTH"
+		alt-msg-connective "ONE OF"
+		alt-connective 'or)
+	(setq msg-connective "ONE OF"
+	      alt-msg-connective "BOTH"
+	      alt-connective 'and))
+      (if (y-or-n-p
+	   (format
+	    "Focusing on diff regions that match %s regexps. Use %s instead? "
+	    msg-connective alt-msg-connective))
+	  (progn
+	    (setq ediff-focus-regexp-connective alt-connective)
+	    (message "Focusing on diff regions that match %s regexps" 
+		     alt-msg-connective))
+	(message "Focusing on diff regions that match %s regexps"
+		 msg-connective))
+      (or (string= regexp-A "") (setq ediff-regexp-focus-A regexp-A))
+      (or (string= regexp-B "") (setq ediff-regexp-focus-B regexp-B))
+      (or (string= regexp-C "") (setq ediff-regexp-focus-C regexp-C))))))
+      
+(defun ediff-toggle-skip-similar ()
+  (interactive)
+  (if (not (eq ediff-auto-refine 'on))
+      (error
+       "Can't skip over whitespace regions: first turn auto-refining on"))
+  (setq ediff-ignore-similar-regions (not ediff-ignore-similar-regions))
+  (if ediff-ignore-similar-regions
+      (message
+       "Skipping regions that differ only in white space & line breaks")
+    (message "Skipping over white-space differences turned off")))
+  
+(defun ediff-focus-on-regexp-matches (n)
+  "Focus on diffs that match regexp `ediff-regexp-focus-A/B'.
+Regions to be ignored according to this function are those where   
+buf A region doesn't match `ediff-regexp-focus-A' and buf B region
+doesn't match `ediff-regexp-focus-B'.
+This function returns nil if the region number N (specified as
+an argument) is not to be ignored and t if region N is to be ignored.
+
+N is a region number used by Ediff internally. It is 1 less
+the number seen by the user."
+  (if (ediff-valid-difference-p n)
+      (let* ((ctl-buf ediff-control-buffer)
+	     (regex-A ediff-regexp-focus-A)
+	     (regex-B ediff-regexp-focus-B)
+	     (regex-C ediff-regexp-focus-C)
+	     (reg-A-match (ediff-eval-in-buffer ediff-buffer-A
+			    (goto-char (ediff-get-diff-posn 'A 'beg n ctl-buf))
+			    (re-search-forward
+			     regex-A
+			     (ediff-get-diff-posn 'A 'end n ctl-buf)
+			     t)))
+	     (reg-B-match (ediff-eval-in-buffer ediff-buffer-B
+			    (goto-char (ediff-get-diff-posn 'B 'beg n ctl-buf))
+			    (re-search-forward
+			     regex-B
+			     (ediff-get-diff-posn 'B 'end n ctl-buf)
+			     t)))
+	     (reg-C-match (if ediff-3way-comparison-job
+			      (ediff-eval-in-buffer ediff-buffer-C
+				(goto-char
+				 (ediff-get-diff-posn 'C 'beg n ctl-buf))
+				(re-search-forward
+				 regex-C
+				 (ediff-get-diff-posn 'C 'end n ctl-buf)
+				 t)))))
+	(not (eval (if ediff-3way-comparison-job
+		       (list ediff-focus-regexp-connective
+			     reg-A-match reg-B-match reg-C-match)
+		     (list ediff-focus-regexp-connective
+			   reg-A-match reg-B-match))))
+	)))
+  
+(defun ediff-hide-regexp-matches (n)  
+  "Hide diffs that match regexp `ediff-regexp-hide-A/B/C'.
+Regions to be ignored are those where buf A region matches
+`ediff-regexp-hide-A' and buf B region matches `ediff-regexp-hide-B'.
+This function returns nil if the region number N (specified as
+an argument) is not to be ignored and t if region N is to be ignored.
+
+N is a region number used by Ediff internally. It is 1 less
+the number seen by the user."
+  (if (ediff-valid-difference-p n)
+      (let* ((ctl-buf ediff-control-buffer)
+	     (regex-A ediff-regexp-hide-A)
+	     (regex-B ediff-regexp-hide-B)
+	     (regex-C ediff-regexp-hide-C)
+	     (reg-A-match (ediff-eval-in-buffer ediff-buffer-A
+			    (goto-char (ediff-get-diff-posn 'A 'beg n ctl-buf))
+			    (re-search-forward
+			     regex-A
+			     (ediff-get-diff-posn 'A 'end n ctl-buf)
+			     t)))
+	     (reg-B-match (ediff-eval-in-buffer ediff-buffer-B
+			    (goto-char (ediff-get-diff-posn 'B 'beg n ctl-buf))
+			    (re-search-forward
+			     regex-B
+			     (ediff-get-diff-posn 'B 'end n ctl-buf)
+			     t)))
+	     (reg-C-match (if ediff-3way-comparison-job
+			      (ediff-eval-in-buffer ediff-buffer-C
+				(goto-char
+				 (ediff-get-diff-posn 'C 'beg n ctl-buf))
+				(re-search-forward
+				 regex-C
+				 (ediff-get-diff-posn 'C 'end n ctl-buf)
+				 t)))))
+	(eval (if ediff-3way-comparison-job
+		  (list ediff-hide-regexp-connective
+			reg-A-match reg-B-match reg-C-match)
+		(list ediff-hide-regexp-connective reg-A-match reg-B-match)))
+	)))
+    
+
+
+;;; Quitting, suspending, etc.
+
+(defun ediff-quit ()
+  "Finish an Ediff session and exit Ediff.
+Unselects the selected difference, if any, restores the read-only and modified
+flags of the compared file buffers, kills Ediff buffers for this session
+\(but not buffers A, B, C\)."
+  (interactive)
+  (if (prog1
+	  (y-or-n-p "Do you really want to exit Ediff? ")
+	(message ""))
+      (ediff-really-quit)))
+
+
+;; Perform the quit operations.
+(defun ediff-really-quit ()
+  (ediff-restore-buffer-characteristics t) ; restore as they were at setup
+  (ediff-unhighlight-diffs-totally)
+  (ediff-clear-diff-vector 'ediff-difference-vector-A 'fine-diffs-also)
+  (ediff-clear-diff-vector 'ediff-difference-vector-B 'fine-diffs-also)
+  (ediff-clear-diff-vector 'ediff-difference-vector-C 'fine-diffs-also)
+  
+  (ediff-delete-temp-files)
+				  
+  ;; Restore visibility range. This affects only ediff-*-regions/windows.
+  ;; Since for other job names ediff-visible-region sets
+  ;; ediff-visible-bounds to ediff-wide-bounds, the settings below are
+  ;; ignored for such jobs.
+  (if ediff-quit-widened
+      (setq ediff-visible-bounds ediff-wide-bounds)
+    (setq ediff-visible-bounds ediff-narrow-bounds))
+  
+  ;; Apply selective display to narrow or widen
+  (ediff-visible-region)
+  (mapcar (function (lambda (overl)
+		      (if (ediff-overlayp overl)
+			  (ediff-delete-overlay overl))))
+	  ediff-wide-bounds)
+  (mapcar (function (lambda (overl)
+		      (if (ediff-overlayp overl)
+			  (ediff-delete-overlay overl))))
+	  ediff-narrow-bounds)
+  
+  ;; restore buffer mode line id's in buffer-A/B/C
+  ;; much of what is here, except for mode line, will be deleted when Emacs
+  ;; acquires before/after-string overlay properties
+  (let ((control-buffer ediff-control-buffer))
+    (condition-case nil
+	(ediff-eval-in-buffer ediff-buffer-A
+	  (setq before-change-function nil)
+	  (setq ediff-this-buffer-control-sessions 
+		(delq control-buffer ediff-this-buffer-control-sessions))
+	  (if (null ediff-this-buffer-control-sessions)
+	      (setq local-write-file-hooks 
+		    (delq 'ediff-block-write-file local-write-file-hooks)))
+	  (kill-local-variable 'ediff-file-checked-out-flag)
+	  (kill-local-variable 'mode-line-buffer-identification)
+	  (kill-local-variable 'mode-line-format)
+	  )
+      (error))
+      
+    (condition-case nil
+	(ediff-eval-in-buffer ediff-buffer-B
+	  (setq ediff-this-buffer-control-sessions 
+		(delq control-buffer ediff-this-buffer-control-sessions))
+	  (if (null ediff-this-buffer-control-sessions)
+	      (setq local-write-file-hooks 
+		    (delq 'ediff-block-write-file local-write-file-hooks)))
+	  (setq before-change-function nil)
+	  (kill-local-variable 'ediff-file-checked-out-flag)
+	  (kill-local-variable 'mode-line-buffer-identification)
+	  (kill-local-variable 'mode-line-format)
+	  )
+      (error))
+    
+    (condition-case nil
+	(ediff-eval-in-buffer ediff-buffer-C
+	  (if (null ediff-this-buffer-control-sessions)
+	      (setq local-write-file-hooks 
+		    (delq 'ediff-block-write-file local-write-file-hooks)))
+	  (setq before-change-function nil)
+	  (kill-local-variable 'ediff-file-checked-out-flag)
+	  (kill-local-variable 'mode-line-buffer-identification)
+	  (kill-local-variable 'mode-line-format)
+	  )
+      (error))
+    )
+  ;; restore state of buffers to what it was before ediff
+  (ediff-restore-protected-variables)
+  (run-hooks 'ediff-quit-hooks))
+  
+  
+(defun ediff-delete-temp-files ()
+  (if (stringp ediff-temp-file-A)
+      (delete-file ediff-temp-file-A))
+  (if (stringp ediff-temp-file-B)
+      (delete-file ediff-temp-file-B))
+  (if (stringp ediff-temp-file-C)
+      (delete-file ediff-temp-file-C)))
+  
+
+;; Kill control buffer, other auxiliary Ediff buffers.
+;; Leave one of the frames split between buffers A/B/C
+(defun ediff-cleanup-mess ()
+  (let ((buff-A ediff-buffer-A)
+	(buff-B ediff-buffer-B)
+	(buff-C ediff-buffer-C)
+	(ctl-buf  ediff-control-buffer)
+	(ctl-frame ediff-control-frame)
+	(three-way-job ediff-3way-job))
+	
+    (ediff-kill-buffer-carefully ediff-diff-buffer)
+    (ediff-kill-buffer-carefully ediff-custom-diff-buffer)
+    (ediff-kill-buffer-carefully ediff-fine-diff-buffer)
+    (ediff-kill-buffer-carefully ediff-tmp-buffer)
+    (ediff-kill-buffer-carefully ediff-error-buffer)
+    (ediff-kill-buffer-carefully ediff-patch-diagnostics)
+    (ediff-kill-buffer-carefully ediff-msg-buffer)
+    (ediff-kill-buffer-carefully ediff-debug-buffer)
+
+    ;; XEmacs 19.11 has a bug (?) that doesn't let us delete buffer in
+    ;; dedicated window. So, we delete the frame first.
+    (redraw-display)
+    (if (and window-system (ediff-frame-live-p ctl-frame))
+	(ediff-delete-frame ctl-frame))
+    (ediff-kill-buffer-carefully ctl-buf)
+      
+    (delete-other-windows)
+    
+    ;; display only if not visible
+    (condition-case nil
+	(or (ediff-get-visible-buffer-window buff-B)
+	    (switch-to-buffer buff-B))
+      (error))
+    (condition-case nil
+	(or (ediff-get-visible-buffer-window buff-A)
+	    (progn
+	      (if (ediff-get-visible-buffer-window buff-B)
+		  (split-window-vertically))
+	      (switch-to-buffer buff-A)))
+      (error))
+    (if three-way-job
+	(condition-case nil
+	    (or (ediff-get-visible-buffer-window buff-C)
+		(progn
+		  (if (or (ediff-get-visible-buffer-window buff-A)
+			  (ediff-get-visible-buffer-window buff-B))
+		      (split-window-vertically))
+		  (switch-to-buffer buff-C)
+		  (balance-windows)))
+	  (error)))
+    (message "")
+    ))
+    
+;; The default way of suspending Ediff.
+;; Buries Ediff buffers, kills all windows.
+(defun ediff-default-suspend-hook ()
+  (let* ((buf-A ediff-buffer-A)
+	 (buf-B ediff-buffer-B)
+	 (buf-C ediff-buffer-C)
+	 (buf-A-wind (ediff-get-visible-buffer-window buf-A))
+	 (buf-B-wind (ediff-get-visible-buffer-window buf-B))
+	 (buf-C-wind (ediff-get-visible-buffer-window buf-C))
+	 (buf-patch ediff-patch-buf)
+	 (buf-patch-diag ediff-patch-diagnostics)
+	 (buf-err  ediff-error-buffer)
+	 (buf-diff ediff-diff-buffer)
+	 (buf-custom-diff ediff-custom-diff-buffer)
+	 (buf-fine-diff ediff-fine-diff-buffer))
+    
+    ;; hide the control panel
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(ediff-iconify-frame ediff-control-frame)
+      (bury-buffer)) 
+    (if buf-err (bury-buffer buf-err))
+    (if buf-diff (bury-buffer buf-diff))
+    (if buf-custom-diff (bury-buffer buf-custom-diff))
+    (if buf-fine-diff (bury-buffer buf-fine-diff))
+    (if buf-patch (bury-buffer buf-patch))
+    (if buf-patch-diag (bury-buffer buf-patch-diag))
+    (if (window-live-p buf-A-wind)
+	(progn
+	  (select-window buf-A-wind)
+	  (delete-other-windows)
+	  (bury-buffer))
+      (if (ediff-buffer-live-p buf-A) (bury-buffer buf-A)))
+    (if (window-live-p buf-B-wind)
+	(progn
+	  (select-window buf-B-wind)
+	  (delete-other-windows)
+	  (bury-buffer))
+      (if (ediff-buffer-live-p buf-B) (bury-buffer buf-B)))
+    (if (window-live-p buf-C-wind)
+	(progn
+	  (select-window buf-C-wind)
+	  (delete-other-windows)
+	  (bury-buffer))
+      (if (ediff-buffer-live-p buf-C) (bury-buffer buf-C)))
+
+    ))
+
+     
+(defun ediff-suspend ()
+  "Suspend Ediff.
+To resume, switch to the appropriate `Ediff Control Panel'
+buffer and then type \\[ediff-recenter].  Ediff will automatically set
+up an appropriate window config."
+  (interactive)
+  (let ((key (substitute-command-keys "\\[ediff-recenter]")))
+  (run-hooks 'ediff-suspend-hooks)
+  (message
+   "To resume, switch to Ediff Control Panel and hit `%s'" key)))
+
+
+(defun ediff-status-info ()
+  "Show the names of the buffers or files being operated on by Ediff.
+Hit \\[ediff-recenter] to reset the windows afterward."
+  (interactive)
+  (with-output-to-temp-buffer " *ediff-info*"
+    (princ (ediff-version))
+    (princ "\n\n")
+    (ediff-eval-in-buffer ediff-buffer-A
+      (if buffer-file-name
+	  (princ
+	   (format "File A = %S\n" buffer-file-name))
+	(princ 
+	 (format "Buffer A = %S\n" (buffer-name)))))
+    (ediff-eval-in-buffer ediff-buffer-B
+      (if buffer-file-name
+	  (princ
+	   (format "File B = %S\n" buffer-file-name))
+	(princ 
+	 (format "Buffer B = %S\n" (buffer-name)))))
+    (if ediff-3way-job
+	(ediff-eval-in-buffer ediff-buffer-C
+	  (if buffer-file-name
+	      (princ
+	       (format "File C = %S\n" buffer-file-name))
+	    (princ 
+	     (format "Buffer C = %S\n" (buffer-name))))))
+			      
+    (let* ((A-line (ediff-eval-in-buffer ediff-buffer-A
+		     (1+ (count-lines (point-min) (point)))))
+	   (B-line (ediff-eval-in-buffer ediff-buffer-B
+		     (1+ (count-lines (point-min) (point)))))
+	   C-line)
+      (princ (format "\Buffer A's point is on line %d\n" A-line))
+      (princ (format "Buffer B's point is on line %d\n" B-line))
+      (if ediff-3way-job
+	  (progn
+	    (setq C-line (ediff-eval-in-buffer ediff-buffer-C
+			   (1+ (count-lines (point-min) (point)))))
+	    (princ (format "Buffer C's point is on line %d\n" C-line)))))
+      
+    (princ (format "\nCurrent difference number = %S\n"
+		   (cond ((< ediff-current-difference 0) 'start)
+			 ((>= ediff-current-difference
+			      ediff-number-of-differences) 'end)
+			 (t (1+ ediff-current-difference)))))
+
+    (cond (ediff-ignore-similar-regions
+	   (princ "\nSkipping regions that differ only in white space & line breaks"))
+	  (t 
+	   (princ "\nNot skipping regions that differ in white space & line breaks")))
+    
+    (cond ((eq ediff-skip-diff-region-function 'ediff-show-all-diffs)
+	   (princ "\nSelective browsing by regexp is off.\n"))
+	  ((eq ediff-skip-diff-region-function 'ediff-hide-regexp-matches)
+	   (princ
+	    "\nIgnoring regions that match")
+	   (princ
+	    (format 
+	     "\n\t regexp `%s' in buffer A  %S\n\t regexp `%s' in buffer B\n"
+	     ediff-regexp-hide-A ediff-hide-regexp-connective
+	     ediff-regexp-hide-B)))
+	  ((eq ediff-skip-diff-region-function 'ediff-focus-on-regexp-matches)
+	   (princ
+	    "\nFocusing on regions that match")
+	   (princ
+	    (format
+	     "\n\t regexp `%s' in buffer A  %S\n\t regexp `%s' in buffer B\n"
+	     ediff-regexp-focus-A ediff-focus-regexp-connective
+	     ediff-regexp-focus-B)))
+	  (t (princ "\nSelective browsing via a user-defined method.\n")))
+    
+    (princ
+     (format "\nBugs/suggestions: type `%s' while in Ediff Control Panel."
+	     (substitute-command-keys "\\[ediff-submit-report]")))
+    ))
+
+
+
+
+;;; Support routines
+
+;; Select a difference by placing the ASCII flags around the appropriate
+;; group of lines in the A, B buffers
+;; This may have to be modified for buffer C, when it will be supported.
+(defun ediff-select-difference (n)
+  (if (and (ediff-buffer-live-p ediff-buffer-A)
+	   (ediff-buffer-live-p ediff-buffer-B)
+	   (ediff-valid-difference-p n))
+      (progn
+	(ediff-remember-buffer-characteristics)
+	(if (and window-system ediff-use-faces)
+	    (progn
+	      (ediff-highlight-diff n)
+	      (setq ediff-highlighting-style 'face))
+	  (setq ediff-highlighting-style 'ascii)
+	  (ediff-place-flags-in-buffer 'A ediff-buffer-A
+				       ediff-control-buffer n)
+	  (ediff-place-flags-in-buffer 'B ediff-buffer-B
+				       ediff-control-buffer n)
+	  (if ediff-3way-job
+	      (ediff-place-flags-in-buffer 'C ediff-buffer-C
+					   ediff-control-buffer n))
+	  ) 
+				       
+	(ediff-install-fine-diff-if-necessary n)
+	  
+	(ediff-restore-buffer-characteristics)
+	(run-hooks 'ediff-select-hooks))))
+	
+
+;; Unselect a difference by removing the ASCII flags in the buffers.
+;; This may have to be modified for buffer C, when it will be supported.
+(defun ediff-unselect-difference (n)
+  (if (ediff-valid-difference-p n)
+      (progn 
+	(ediff-remember-buffer-characteristics)
+	
+	(cond ((and window-system ediff-use-faces)
+	       (ediff-unhighlight-diff))
+	      ((eq ediff-highlighting-style 'ascii)
+	       (ediff-remove-flags-from-buffer
+		ediff-buffer-A
+		(ediff-get-diff-overlay n 'A)
+		(ediff-get-diff-posn 'A 'beg n)
+		(ediff-get-diff-posn 'A 'end n)
+		ediff-before-flag-A ediff-after-flag-A)
+	       (ediff-remove-flags-from-buffer
+		ediff-buffer-B
+		(ediff-get-diff-overlay n 'B)
+		(ediff-get-diff-posn 'B 'beg n)
+		(ediff-get-diff-posn 'B 'end n)
+		ediff-before-flag-B ediff-after-flag-B)
+	       (if ediff-3way-job
+		   (ediff-remove-flags-from-buffer
+		    ediff-buffer-C
+		    (ediff-get-diff-overlay n 'C)
+		    (ediff-get-diff-posn 'C 'beg n)
+		    (ediff-get-diff-posn 'C 'end n)
+		    ediff-before-flag-C ediff-after-flag-C))
+	       ))
+		
+	(ediff-restore-buffer-characteristics)
+	(setq ediff-highlighting-style nil)
+	
+	;; unhighlight fine diffs
+	(ediff-set-fine-diff-properties ediff-current-difference 'default)
+	
+	(run-hooks 'ediff-unselect-hooks))))
+  
+
+;; Unselects prev diff and selects a new one, if FLAG has value other than
+;; 'select-only or 'unselect-only.  If FLAG is 'select-only, the
+;; next difference is selected, but the current selection is not
+;; unselected.  If FLAG is 'unselect-only then the current selection is
+;; unselected, but the next one is not selected.  If NO-RECENTER is non-nil,
+;; don't recenter buffers after selecting/unselecting.
+;; 
+;; Don't use `ediff-select-difference' and `ediff-unselect-difference'
+;; directly, since this will screw up the undo info in the presence of
+;; ASCII flags. 
+;; Instead, use `ediff-unselect-and-select-difference' with appropriate
+;; flags.
+
+(defun ediff-unselect-and-select-difference (n &optional flag no-recenter)
+  (let (;; save buf modified info
+	(control-buf ediff-control-buffer)
+	(buf-A-modified (buffer-modified-p ediff-buffer-A))
+	(buf-B-modified (buffer-modified-p ediff-buffer-B))
+	;; temporarily disable undo so highlighting won't confuse the user
+	buf-C-modified buf-A-undo buf-B-undo buf-C-undo)
+	
+    (let ((ediff-current-difference n))
+      (or no-recenter
+	  (ediff-recenter 'no-rehighlight)))
+	  
+    (if (and (ediff-buffer-live-p ediff-buffer-A) 
+	     (ediff-buffer-live-p ediff-buffer-B))
+	(progn
+	  (ediff-eval-in-buffer ediff-buffer-A
+	    (setq buf-A-undo buffer-undo-list))
+	  (ediff-eval-in-buffer ediff-buffer-B
+	    (setq buf-B-undo buffer-undo-list))
+	  (buffer-disable-undo ediff-buffer-A)
+	  (buffer-disable-undo ediff-buffer-B)))
+	  
+    (if (ediff-buffer-live-p ediff-buffer-C)
+	(progn
+	  (setq buf-C-modified (buffer-modified-p ediff-buffer-C))
+	  (ediff-eval-in-buffer ediff-buffer-C
+	    (setq buf-C-undo buffer-undo-list))
+	  (buffer-disable-undo ediff-buffer-C)))
+    
+    (unwind-protect    ; we don't want to lose undo info due to error
+	(progn
+	  (or (eq flag 'select-only)
+	      (ediff-unselect-difference ediff-current-difference))
+	  
+	  ;; Auto-save buffers while Ediff flags are temporarily removed.
+	  (ediff-eval-in-buffer ediff-buffer-A
+	    (if buf-A-modified (do-auto-save)))
+	  (ediff-eval-in-buffer ediff-buffer-B
+	    (if buf-B-modified (do-auto-save)))
+	  (if (ediff-buffer-live-p ediff-buffer-C)
+	      (ediff-eval-in-buffer ediff-buffer-C
+		(if buf-C-modified (do-auto-save))))
+	  
+	  (or (eq flag 'unselect-only)
+	      (ediff-select-difference n))
+	  (setq ediff-current-difference n)
+	  ) ; end protected section
+      
+      (ediff-eval-in-buffer control-buf
+	(ediff-refresh-mode-lines)
+	;; restore undo and buffer-modified info
+	(ediff-eval-in-buffer ediff-buffer-A
+	  (set-buffer-modified-p buf-A-modified)
+	  (setq buffer-undo-list buf-A-undo)))
+      (ediff-eval-in-buffer control-buf
+	(ediff-eval-in-buffer ediff-buffer-B
+	  (set-buffer-modified-p buf-B-modified)
+	  (setq buffer-undo-list buf-B-undo)))
+      (if (ediff-buffer-live-p ediff-buffer-C)
+	  (ediff-eval-in-buffer control-buf
+	    (ediff-eval-in-buffer ediff-buffer-C
+	      (set-buffer-modified-p buf-C-modified)
+	      (setq buffer-undo-list buf-C-undo))))
+      )))
+
+
+(defun ediff-read-file-name (prompt default-dir default-file)
+; This is a modified version of a similar function in `emerge.el'.
+; PROMPT should not have trailing ': ', so that it can be modified
+; according to context.
+; If default-file is set, it should be used as the default value.
+; If default-dir is non-nil, use it as the default directory.
+; Otherwise, use the value of Emacs' variable `default-directory.'
+
+  ;; hack default-dir if it is not set
+  (setq default-dir
+	(file-name-as-directory
+	 (abbreviate-file-name
+	  (expand-file-name (or default-dir
+				(and default-file
+				     (file-name-directory default-file))
+				default-directory)))))
+
+  ;; strip the directory from default-file
+  (if default-file
+      (setq default-file (file-name-nondirectory default-file)))
+  (if (string= default-file "")
+      (setq default-file nil))
+
+  (let (f)
+    (setq f (expand-file-name
+	     (read-file-name
+	      (format "%s%s: "
+		      prompt
+		      (if default-file
+			  (concat " (default " default-file ")")
+			""))
+	      default-dir
+	      default-file
+	      'confirm
+	      (if default-file (file-name-directory default-file))
+	      )
+	     default-dir
+	     ))
+    ;; If user enters a directory name, expand the default file in that
+    ;; directory.  This allows the user to enter a directory name for the
+    ;; B-file and diff against the default-file in that directory instead
+    ;; of a DIRED listing!
+    (if (and (file-directory-p f) default-file)
+	(setq f (expand-file-name
+		 (file-name-nondirectory default-file) f)))
+    f)) 
+  
+;; If `prefix' is given, then it is used as a prefix for the temp file
+;; name. Otherwise, `_buffer-name' is used. If `file' is given, use this
+;; file and don't create a new one.
+(defun ediff-make-temp-file (&optional prefix given-file start end)
+  (let ((f (or given-file
+	       (make-temp-name (concat
+				ediff-temp-file-prefix
+				(if prefix
+				    (concat prefix "_")
+				    "ediff_"))))))
+    ;; create the file
+    (write-region (if start start (point-min))
+		  (if end end (point-max))
+		  f
+		  nil          ; don't append---erase
+		  'no-message) 
+    (set-file-modes f ediff-temp-file-mode)
+    f))
+
+;; Quote metacharacters (using \) when executing diff in Unix, but not in
+;; EMX OS/2
+(defun ediff-protect-metachars (str)
+  (or (memq system-type '(emx vax-vms axp-vms))
+      (let ((limit 0))
+	(while (string-match ediff-metachars str limit)
+	  (setq str (concat (substring str 0 (match-beginning 0))
+			    "\\"
+			    (substring str (match-beginning 0))))
+	  (setq limit (1+ (match-end 0))))))
+  str)
+
+;; Make sure the current buffer (for a file) has the same contents as the
+;; file on disk, and attempt to remedy the situation if not.
+;; Signal an error if we can't make them the same, or the user doesn't want
+;; to do what is necessary to make them the same.
+;; If file has file handlers (indicated by the optional arg), then we
+;; offer to instead of saving. This is one difference with Emerge. 
+;; Another is that we always offer to revert obsolete files, whether they
+;; are modified or not.
+(defun ediff-verify-file-buffer (&optional file-magic)
+  ;; First check if the file has been modified since the buffer visited it.
+  (if (verify-visited-file-modtime (current-buffer))
+      (if (buffer-modified-p)
+	  ;; If buffer is not obsolete and is modified, offer to save
+	  (if (yes-or-no-p 
+	       (format "Buffer out of sync with visited file. %s file %s? "
+		       (if file-magic "Revert" "Save")
+		       buffer-file-name))
+	      (if (not file-magic)
+		  (save-buffer)
+		;; for some reason, file-name-handlers append instead of
+		;; replacing, so we have to erase first.
+		(erase-buffer)
+		(revert-buffer t t))
+	    (error "Buffer out of sync for file %s" buffer-file-name))
+	;; If buffer is not obsolete and is not modified, do nothing
+	nil)
+    ;; If buffer is obsolete, offer to revert
+    (if (yes-or-no-p
+	 (format "Buffer out of sync with visited file. Revert file %s? "
+		 buffer-file-name))
+	(progn
+	  (if file-magic
+	      (erase-buffer))
+	  (revert-buffer t t))
+      (error "Buffer out of sync for file %s" buffer-file-name))))
+
+
+;; to be deleted in due time
+(defun ediff-block-write-file ()    
+  "Prevent writing files A and B directly."
+  (if (ediff-check-for-ascii-flags)
+      (error "Type `wa' and `wb' in Ediff Control Panel to save buffs A/B")))
+
+;; To be deleted in due time
+(defun ediff-before-change-guard (start end)
+  "If buffer is highlighted with ASCII flags, remove highlighting.
+Arguments, START and END are not used, but are provided
+because this is required by `before-change-function'."
+  (let (rehighlight-key)
+    (save-window-excursion
+      (mapcar
+       (function
+	(lambda (buf)
+	  (ediff-eval-in-buffer buf
+	    (if (eq ediff-highlighting-style 'ascii)
+		(progn
+		  (ediff-unselect-and-select-difference
+		   ediff-current-difference 
+		   'unselect-only 'no-recenter)
+		  (setq rehighlight-key
+			(substitute-command-keys "\\[ediff-recenter]"))
+		  )))))
+       ediff-this-buffer-control-sessions)
+      (if rehighlight-key
+	  (error 
+	   "ASCII flags removed. You can edit now. Hit `%s' to rehighlight"
+	   rehighlight-key))
+     )))
+     
+
+(defun ediff-check-for-ascii-flags ()
+  (eval
+   (cons 'or
+	 (mapcar (function (lambda (buf)
+			     (if (ediff-buffer-live-p buf)
+				 (ediff-eval-in-buffer buf
+				   (eq ediff-highlighting-style 'ascii)))))
+		 ediff-this-buffer-control-sessions))))
+
+;; It would be nice to use these two functions as hooks instead of
+;; ediff-insert-in-front and ediff-move-disturbed-overlays.
+;; However, Emacs has a bug that causes BEG and END, below, to be
+;; the same, i.e., the end of inserted text is not passed correctly.
+;; Since the overlay doesn't move when these hooks run, 
+;; there is no way to correctly determine the new (desired) position of
+;; the overlay end.
+;; Either this bug is fixed, or (better) use sticky overlays when they will
+;; be implemented in Emacs, like they are in XEmacs.
+;;(defun ediff-capture-inserts-in-front (overl beg end)
+;;  (if (ediff-overlay-get overl 'ediff-diff-num)
+;;      (ediff-move-overlay
+;;       overl beg (+ (- end beg) (ediff-overlay-end overl)))
+;;  ))
+;;(defun ediff-capture-inserts-behind (overl beg end)
+;;  (if (ediff-overlay-get overl 'ediff-diff-num)
+;;      (ediff-move-overlay overl (ediff-overlay-start overl) end))
+;;  ))
+  
+;; to be deleted in due time
+;; Capture overlays that had insertions in the front.
+;; Called when overlay OVERL gets insertion in front.
+(defun ediff-insert-in-front (overl &optional flag beg end length)
+  (if (ediff-overlay-get overl 'ediff-diff-num)
+      (setq ediff-disturbed-overlays
+	    (cons overl ediff-disturbed-overlays))))
+  
+;; to be deleted in due time
+;; Collects all extents at POS having property `ediff-diff-num'.
+;; XEmacs causes headache by detaching empty extents, so I have to save
+;; them before they disappear.
+(defun ediff-collect-extents-xemacs (pos)
+  (let (lis elt)
+    (while (setq elt (extent-at pos nil 'ediff-diff-num elt))
+      (setq lis (cons elt lis)))
+    (setq ediff-disturbed-overlays lis)))
+  
+;; to be deleted in due time
+;; We can't move overlays directly in insert-in-front-hooks
+;; because when diff is highlighted  with ascii flags, they will  disturb
+;; overlays and so they will be included in them, which we don't want.
+(defun  ediff-move-disturbed-overlays (posn)  
+  (mapcar (function (lambda (overl)
+		       (ediff-move-overlay overl
+					   posn
+					   (ediff-overlay-end overl))
+		       ))
+	  ediff-disturbed-overlays)
+  (setq ediff-disturbed-overlays nil))
+  
+;; to be deleted in due time
+;; If XEmacs adds the ability to not detach extents, we should be able to
+;; delete this
+(defun ediff-adjust-disturbed-extents-xemacs (posn)
+  (mapcar (function (lambda (overl)
+		       (if (equal (ediff-overlay-start overl)
+				  (ediff-overlay-end overl))
+			   (ediff-move-overlay overl posn posn))))
+	  ediff-disturbed-overlays)
+    (setq ediff-disturbed-overlays nil))
+  
+(defun ediff-save-buffer (arg)
+  "Safe way of saving buffers A, B, C, and the diff output.
+`wa' saves buffer A, `wb' saves buffer B, `wc' saves buffer C,
+and `wd' saves the diff output."
+  (interactive "P")
+  (let ((hooks local-write-file-hooks))
+    (ediff-unselect-and-select-difference ediff-current-difference
+					  'unselect-only)
+    (unwind-protect
+	(ediff-eval-in-buffer
+	    (cond ((memq last-command-char '(?a ?b ?c))
+		    (ediff-get-buffer
+		     (ediff-char-to-buftype last-command-char)))
+		  ((eq last-command-char ?d)
+		   (message "Saving diff output ...")(sit-for 1)
+		   (if arg ediff-diff-buffer ediff-custom-diff-buffer)
+		   ))
+	  ;; temporarily remove writing block 
+	  (setq hooks (delq 'ediff-block-write-file hooks))
+	  (let ((local-write-file-hooks hooks))
+	    (save-buffer)))
+      (ediff-unselect-and-select-difference ediff-current-difference
+					    'select-only)
+      )))
+    
+
+;; will simplify it in due time, when emacs acquires before/after strings
+(defun ediff-remove-flags-from-buffer (buffer overlay before-posn after-posn
+					      before-flag after-flag)
+  (ediff-eval-in-buffer buffer
+    (let ((before-flag-length (length before-flag))
+	  (after-flag-length (length after-flag))
+	  (inhibit-read-only t)
+	  buffer-read-only
+	  before-change-function)
+      (goto-char after-posn)
+      (setq after-posn (point-marker)) ; after-posn is now a marker
+      ;; remove the flags, if they're there
+      (goto-char (- before-posn before-flag-length))
+      (if ediff-xemacs-p
+	  (ediff-overlay-put overlay 'begin-glyph nil)
+	;; before-string is not yet implemented in emacs.
+	;; when it will be, I will be able to delete much of the rest of
+	;; this function
+	(ediff-overlay-put overlay 'before-string nil)
+	(if (looking-at (regexp-quote before-flag))
+	    (delete-region (point) (+ (point) before-flag-length))
+	  ;; flag isn't there
+	  (ding)
+	  (message "Trouble removing ASCII flag"))
+	)
+      
+      (if ediff-xemacs-p
+	  (ediff-overlay-put overlay 'end-glyph nil)
+	;; after-string is not yet implemented in emacs.
+	(ediff-overlay-put overlay 'after-string nil)
+	(goto-char after-posn)
+	(if (looking-at (regexp-quote after-flag))
+	    (delete-region (point) (+ (point) after-flag-length))
+	  ;; flag isn't there
+	  (ding)
+	  (message "Trouble removing ASCII flag"))
+	(setq after-posn nil) ; after has become a marker--garbage-collect
+	)
+      )))
+
+
+
+;; will simplify it in due time, when emacs acquires before/after strings
+(defun ediff-place-flags-in-buffer (buf-type buffer ctl-buffer diff)
+  (ediff-eval-in-buffer buffer
+    (ediff-place-flags-in-buffer1 buf-type ctl-buffer diff)))
+
+
+(defun ediff-place-flags-in-buffer1 (buf-type ctl-buffer diff-no)
+  (let* ((before-flag-name (intern (format "ediff-before-flag-%S" buf-type)))
+	 (after-flag-name (intern (format "ediff-after-flag-%S" buf-type)))
+	 (curr-overl (ediff-eval-in-buffer ctl-buffer
+		       (ediff-get-diff-overlay diff-no buf-type)))
+	 (inhibit-read-only t)
+	 (narrow-overlay (ediff-eval-in-buffer ctl-buffer
+			   (ediff-get-value-according-to-buffer-type
+			    buf-type ediff-narrow-bounds)))
+	 (wide-overlay (ediff-eval-in-buffer ctl-buffer
+			 (ediff-get-value-according-to-buffer-type
+			  buf-type ediff-wide-bounds)))
+	 (visibility-overlay (ediff-eval-in-buffer ctl-buffer
+			       (ediff-get-value-according-to-buffer-type
+				buf-type ediff-visible-bounds)))
+	 (visibility-min (ediff-overlay-start visibility-overlay))
+	 (visibility-max (ediff-overlay-end visibility-overlay))
+	 (before (ediff-get-diff-posn buf-type 'beg diff-no ctl-buffer))
+	 after buffer-read-only before-change-function beg-of-line flag)
+	
+    ;; we need it to be a marker
+    (setq visibility-max
+	  (move-marker
+	   (make-marker) (if (numberp visibility-max) visibility-max 1)))
+    
+    (widen)
+	
+    ;; insert flag before the difference
+    (goto-char before)
+    (setq beg-of-line (bolp))
+    
+    (setq flag (ediff-eval-in-buffer ctl-buffer
+		 (if beg-of-line
+		     (set before-flag-name ediff-before-flag-bol)
+		   (set before-flag-name ediff-before-flag-mol))))
+    
+    ;; insert the flag itself
+    (if ediff-xemacs-p
+	(ediff-overlay-put curr-overl 'begin-glyph flag)
+      ;; before-string is not yet implemented in emacs.
+      ;; when it will, I will be able to delete much of the rest of this
+      ;; function
+      ;;(ediff-overlay-put curr-overl 'before-string flag)
+      (insert-before-markers flag)
+      (if (or (not (numberp visibility-min)) (< before visibility-min))
+	  (setq visibility-min before))
+      )
+    
+    ;; insert the flag after the difference
+    ;; `after' must be set here, after the before-flag was inserted
+    (setq after (ediff-get-diff-posn buf-type 'end diff-no ctl-buffer))
+    (goto-char after)
+    (setq beg-of-line (bolp))
+    
+    (setq flag (ediff-eval-in-buffer ctl-buffer
+		 (if beg-of-line
+		     (set after-flag-name ediff-after-flag-eol)
+		   (set after-flag-name ediff-after-flag-mol))))
+    
+    ;; insert the flag itself
+    (if ediff-xemacs-p
+	;; In XEmacs, end-glyph of a 0-length overlay is not inserted.
+	;; Hopefully, this bug will be fixed in 19.12.
+	(ediff-overlay-put curr-overl 'end-glyph flag)
+      ;; after-string is not yet implemented in emacs.
+      ;;(ediff-overlay-put curr-overl 'after-string flag)
+      (insert flag)
+      (if (> (point) visibility-max)
+	  (move-marker visibility-max (point)))
+      )
+    (narrow-to-region visibility-min visibility-max)
+    (ediff-move-overlay wide-overlay
+			(min before
+			     (ediff-overlay-start wide-overlay))
+			(max (point)
+			     (ediff-overlay-end wide-overlay)))
+    (ediff-move-overlay narrow-overlay
+			(min before
+			     (ediff-overlay-start narrow-overlay))
+			(max (point)
+			     (ediff-overlay-end narrow-overlay)))
+    
+    (setq visibility-max nil)  ; garbage-collect it
+    ))
+
+  
+(defun ediff-get-diff-posn (buf-type pos &optional n control-buf)
+  "Returns positions of difference sectors in the BUF-TYPE buffer.
+BUF-TYPE should be a symbol--either `A' or `B'. 
+POS is either `beg' or `end'--it specifies whether you want the position at the
+beginning of a difference or at the end.
+
+The optional argument N says which difference \(default:
+`ediff-current-difference'\).  The optional argument CONTROL-BUF says
+which control buffer is in effect in case it is not the current
+buffer."
+  (let (diff-overlay)
+    (or control-buf
+	(setq control-buf (current-buffer)))
+
+    (ediff-eval-in-buffer control-buf
+      (or n  (setq n ediff-current-difference))
+      (if (or (< n 0) (>= n ediff-number-of-differences))
+	  (if (> ediff-number-of-differences 0)
+	      (error "There is no diff %d. Valid diffs are 1 to %d"
+		     (1+ n) ediff-number-of-differences)
+	    (error "No differences found")))
+      (setq diff-overlay (ediff-get-diff-overlay n buf-type)))
+    
+    (if (eq pos 'beg)
+	(ediff-overlay-start diff-overlay)
+      (ediff-overlay-end diff-overlay))
+    ))
+
+
+
+(defun ediff-highlight-diff-in-one-buffer (n buf-type)
+  (if (ediff-buffer-live-p (ediff-get-buffer buf-type))
+      (let* ((buff (ediff-get-buffer buf-type))
+	     (last (ediff-eval-in-buffer buff (point-max)))
+	     (begin (ediff-get-diff-posn buf-type 'beg n))
+	     (end (ediff-get-diff-posn buf-type 'end n))
+	     (xtra (if (equal begin end) 1 0))
+	     (end-hilit (min last (+ end xtra)))
+	     (current-diff-overlay 
+	      (symbol-value
+	       (intern (format "ediff-current-diff-overlay-%S" buf-type))))
+	     (odd-diff-face
+	      (symbol-value
+	       (intern (format "ediff-odd-diff-face-%S" buf-type))))
+	     (even-diff-face
+	      (symbol-value
+	       (intern (format "ediff-even-diff-face-%S" buf-type))))
+	     (odd-diff-face-var
+	      (intern (format "ediff-odd-diff-face-%S-var" buf-type)))
+	     (even-diff-face-var
+	      (intern (format "ediff-even-diff-face-%S-var" buf-type)))
+	     )
+	
+	(if ediff-xemacs-p
+	    (ediff-move-overlay
+	     current-diff-overlay begin end-hilit)
+	  ;; Emacs 19.22 has a bug, which requires that ediff-move-overlay will
+	  ;; have the buffer as a parameter.  Believed fixed in 19.23.
+	  (ediff-move-overlay current-diff-overlay
+			      begin end-hilit buff))
+	;; giving priority of 0 and then changing it may look funny, but
+	;; this overcomes an obscure Emacs bug.
+	(ediff-overlay-put current-diff-overlay 'priority  0)
+	(ediff-overlay-put current-diff-overlay 'priority  
+			   (ediff-highest-priority begin end-hilit buff))
+	
+	(or (face-differs-from-default-p odd-diff-face-var)
+	    (not ediff-highlight-all-diffs)
+	    (progn
+	      (copy-face odd-diff-face odd-diff-face-var)
+	      (copy-face even-diff-face even-diff-face-var)))
+	
+	;; unhighlight the background overlay for diff n so they won't
+	;; interfere with the current diff overlay
+	(ediff-overlay-put (ediff-get-diff-overlay n buf-type) 'face nil)
+	)))
+
+
+(defun ediff-unhighlight-diff-in-one-buffer (buf-type)
+  (if (ediff-buffer-live-p (ediff-get-buffer buf-type))
+      (let ((current-diff-overlay 
+	     (symbol-value
+	      (intern (format "ediff-current-diff-overlay-%S" buf-type))))
+	    (odd-diff-face-var
+	     (intern (format "ediff-odd-diff-face-%S-var" buf-type)))
+	    (even-diff-face-var
+	     (intern (format "ediff-even-diff-face-%S-var" buf-type)))
+	    (overlay
+	     (ediff-get-diff-overlay ediff-current-difference buf-type))
+	    )
+    
+	(ediff-move-overlay current-diff-overlay 1 1)
+	
+	;; rehighlight the overlay in the background of the
+	;; current difference region
+	(ediff-overlay-put overlay
+			   'face (if (ediff-odd-p ediff-current-difference)
+				     odd-diff-face-var
+				   even-diff-face-var))
+	)))
+
+(defun ediff-unhighlight-diffs-totally-in-one-buffer (buf-type)
+  (let (buffer-read-only)
+    (ediff-unselect-and-select-difference -1)
+    (if (and window-system ediff-use-faces)
+	(let* ((inhibit-quit t)
+	       (current-diff-overlay-var
+		(intern (format "ediff-current-diff-overlay-%S" buf-type)))
+	       (current-diff-overlay (symbol-value current-diff-overlay-var))
+	       (odd-diff-face-var
+		(intern (format "ediff-odd-diff-face-%S-var" buf-type)))
+	       (even-diff-face-var
+		(intern (format "ediff-even-diff-face-%S-var" buf-type))))
+	  (if (face-differs-from-default-p odd-diff-face-var)
+	      (progn
+		(copy-face 'default odd-diff-face-var)
+		(copy-face 'default even-diff-face-var)))
+	  (if (ediff-overlayp current-diff-overlay)
+	      (ediff-delete-overlay current-diff-overlay))
+	  (set current-diff-overlay-var nil)
+	  ))
+    ))
+
+    
+;; null out difference overlays so they won't slow down future
+;; editing operations
+;; VEC is either a difference vector or a fine-diff vector
+(defun ediff-clear-diff-vector (vec-var &optional fine-diffs-also)
+  (if (vectorp (symbol-value vec-var))
+      (mapcar (function
+	       (lambda (elt)
+		 (ediff-delete-overlay 
+		  (ediff-get-diff-overlay-from-diff-record elt))
+		 (if fine-diffs-also
+		     (ediff-clear-fine-diff-vector elt))
+		 ))
+	      (symbol-value vec-var)))
+  ;; allow them to be garbage collected
+  (set vec-var nil))
+    
+(defun ediff-operate-on-flags (action)
+  "Re/unhighlights buffers A and B with all flags from all Ediff sessions.
+This is usually needed only when a
+buffer is involved in multiple Ediff sessions."
+  (let* ((A-sessions (ediff-eval-in-buffer ediff-buffer-A
+		       ediff-this-buffer-control-sessions))
+	 (B-sessions (ediff-eval-in-buffer ediff-buffer-B
+		       ediff-this-buffer-control-sessions))
+	 (C-sessions (if ediff-3way-job
+			(ediff-eval-in-buffer ediff-buffer-C
+			  ediff-this-buffer-control-sessions)))
+	 (sessions (ediff-union
+		    (ediff-union A-sessions B-sessions) C-sessions))
+	 (flag (if (eq action 'remove) 'unselect-only 'select-only)))
+	 
+    (mapcar (function
+	     (lambda (buf)
+	       (if (ediff-buffer-live-p buf)
+		   (ediff-eval-in-buffer buf
+		     (or (if (eq action 'insert)
+			     (memq ediff-highlighting-style '(ascii off))
+			   (not (eq ediff-highlighting-style 'ascii)))
+			 (ediff-unselect-and-select-difference
+			  ediff-current-difference 
+			  flag 'no-recenter))
+		     ))))
+	    sessions)))
+
+
+       
+
+;;; Misc
+
+;; These two functions are here to neutralize XEmacs unwillingless to
+;; handle overlays whose buffers were deleted.
+(defun ediff-move-overlay (overlay beg end &optional buffer)
+  "Calls `move-overlay' in Emacs and `set-extent-endpoints' in Lemacs.
+Checks if overlay's buffer exists before actually doing the move."
+  (let ((buf (and overlay (ediff-overlay-buffer overlay))))
+    (if (ediff-buffer-live-p buf)
+	(if ediff-xemacs-p
+	    (progn
+	      (set-extent-endpoints overlay beg end)
+	      (set-extent-property overlay 'ediff-marker beg))
+	  (move-overlay overlay beg end buffer))
+      ;; buffer's dead
+      (if overlay
+	  (ediff-delete-overlay overlay)))))
+	  
+(defun ediff-overlay-put (overlay prop value)
+  "Calls `overlay-put' or `set-extent-property' depending on Emacs version.
+Checks if overlay's buffer exists."
+  (if (ediff-buffer-live-p (ediff-overlay-buffer overlay))
+      (if ediff-xemacs-p
+	  (set-extent-property overlay prop value)
+	(overlay-put overlay prop value))
+    (ediff-delete-overlay overlay)))
+    
+
+;; In Emacs 19.23 and XEmacs 19.10, the number of variables to
+;; file-name-handler has changed.
+(defun ediff-find-file-name-handler (file)
+  (let (newvers)
+    (setq newvers (if ediff-xemacs-p
+		      (ediff-check-version '> 19 9)
+		    (ediff-check-version '> 19 22)))
+    (if newvers
+	(find-file-name-handler file 'find-file-noselect)
+      (find-file-name-handler file))))
+      
+;; In XEmacs, it checks if the overlay is detached. If so, it reattaches
+;; this overlay at position specified by ediff-marker.
+;; If extent is not detached, it simply returns the start point.
+;; In Emacs, this is the same as overlay-start.
+;; If arg is not overlay, retuns nil
+(defun ediff-overlay-start (overl)
+  (if (ediff-overlay-p overl)
+      (if ediff-emacs-p
+	  (overlay-start overl)
+	(let ((pos (extent-property overl 'ediff-marker)))
+	  (if (and (ediff-overlay-get overl 'detached)
+		   (number-or-marker-p pos))
+	      (ediff-move-overlay overl pos pos))
+	  (extent-start-position overl)))))
+    
+;; In XEmacs, it checks if the overlay is detached. If so, it reattaches
+;; this overlay at position specified by ediff-marker.
+;; If extent is not detached, it simply returns the end point.
+;; In Emacs, this is the same as overlay-end.
+(defun ediff-overlay-end (overl)
+  (if (ediff-overlay-p overl)
+      (if ediff-emacs-p
+	  (overlay-end overl)
+	(let ((pos (extent-property overl 'ediff-marker)))
+	  (if (and (ediff-overlay-get overl 'detached)
+		   (number-or-marker-p pos))
+	      (ediff-move-overlay overl pos pos))
+	  (extent-end-position overl)))))
+    
+;; Makes overlays that remember their position, even if detached in XEmacs.
+;; In Emacs, this just makes overlay. In the future, when Emacs will start
+;; supporting sticky overlays, this function will make a sticky overlay.
+;; BEG and END are expressions telling where overlay starts.
+;; If they are numbers or buffers, then all is well. Otherwise, they must
+;; be expressions to be evaluated in buffer BUF in order to get the overlay
+;; bounds.
+;; If BUFF is not a live buffer, then return nil; otherwise, return the
+;; newly created overlay.
+(defun ediff-make-bullet-proof-overlay (beg end buff)
+  (if (ediff-buffer-live-p buff)
+      (let (overl)
+	(ediff-eval-in-buffer buff
+	  (or (number-or-marker-p beg)
+	      (setq beg (eval beg)))
+	  (or (number-or-marker-p end)
+	      (setq end (eval end)))
+	  (setq overl (ediff-make-overlay beg end buff))
+	  
+	  (if ediff-xemacs-p
+	      (progn
+		;; take precautions against detached extents
+		(ediff-overlay-put
+		 overl 'ediff-marker (move-marker (make-marker) beg buff))
+		;; chars inserted at both ends will be inside extent
+		(ediff-overlay-put overl 'start-open nil)
+		(ediff-overlay-put overl 'end-open nil))
+	    (ediff-overlay-put overl 'ediff-diff-num 0)
+	    ;;(ediff-overlay-put overl 'insert-in-front-hooks
+	    ;;		         (list 'ediff-capture-inserts-in-front))
+	    ;;(ediff-overlay-put overl 'insert-behind-hooks
+	    ;;  	         (list 'ediff-capture-inserts-behind))
+	    ;; These two are not yet implemented in Emacs
+	    ;;(ediff-overlay-put overl 'rear-sticky t)
+	    ;;(ediff-overlay-put overl 'front-sticky t)
+	    )
+	  overl))))
+
+  
+;; Check the current version against the major and minor version numbers
+;; using op: cur-vers op major.minor If emacs-major-version or
+;; emacs-minor-version are not defined, we assume that the current version
+;; is hopelessly outdated.  We assume that emacs-major-version and
+;; emacs-minor-version are defined.  Otherwise, for Emacs/XEmacs 19, if the
+;; current minor version is < 10 (xemacs) or < 23 (emacs) the return value
+;; will be nil (when op is =, >, or >=) and t (when op is <, <=), which may be
+;; incorrect. However, this gives correct result in our cases, since we are
+;; testing for sufficiently high Emacs versions.
+(defun ediff-check-version (op major minor &optional type-of-emacs)
+  (if (and (boundp 'emacs-major-version) (boundp 'emacs-minor-version))
+      (and (cond ((eq type-of-emacs 'xemacs) ediff-xemacs-p)
+		 ((eq type-of-emacs 'emacs) ediff-emacs-p)
+		 (t t))
+	   (cond ((eq op '=) (and (= emacs-minor-version minor)
+				  (= emacs-major-version major)))
+		 ((memq op '(> >= < <=))
+		  (and (or (funcall op emacs-major-version major)
+			   (= emacs-major-version major))
+		       (if (= emacs-major-version major)
+			   (funcall op emacs-minor-version minor)
+			 t)))
+		 (t
+		  (error "%S: Invalid op in ediff-check-version" op))))
+    (cond ((memq op '(= > >=)) nil)
+	  ((memq op '(< <=)) t))))
+  
+      
+;; Like other-buffer, but prefers visible buffers and ignores temporary or
+;; other insignificant buffers (those beginning with "^[ *]").
+;; Gets one arg--buffer name or a list of buffer names (it won't return
+;; these buffers).
+(defun ediff-other-buffer (buff)
+  (if (not (listp buff)) (setq buff (list buff)))
+  (let* ((screen-buffers (buffer-list))
+	 (significant-buffers
+	  (mapcar
+	   (function (lambda (x)
+		       (cond ((member (buffer-name x) buff)
+			      nil)
+			     ((not (ediff-get-visible-buffer-window x))
+			      nil)
+			     ((string-match "^ " (buffer-name x))
+			      nil)
+			     (t x))))
+	   screen-buffers))
+	 (buffers (delq nil significant-buffers))
+	 less-significant-buffers)
+	 
+    (cond (buffers (car buffers))
+	  ;; try also buffers that are not displayed in windows
+	  ((setq less-significant-buffers
+		 (delq nil
+		       (mapcar
+			(function
+			 (lambda (x)
+			   (cond ((member (buffer-name x) buff) nil)
+				 ((string-match "^[ *]" (buffer-name x)) nil)
+				 (t x))))
+			screen-buffers)))
+	   (car less-significant-buffers))
+	  (t (other-buffer (current-buffer))))
+    ))
+      
+      
+;; Construct a unique buffer name.
+;; The first one tried is prefixsuffix, then prefix<2>suffix, 
+;; prefix<3>suffix, etc.
+(defun ediff-unique-buffer-name (prefix suffix)
+  (if (null (get-buffer (concat prefix suffix)))
+      (concat prefix suffix)
+    (let ((n 2))
+      (while (get-buffer (format "%s<%d>%s" prefix n suffix))
+	(setq n (1+ n)))
+      (format "%s<%d>%s" prefix n suffix))))
+  
+
+;; Early versions of XEmacs didn't have window-live-p (or it didn't work right)
+(if (ediff-check-version '< 19 11 'xemacs)
+    (defun window-live-p (win)
+      (let (visible)
+	(walk-windows
+	 '(lambda (walk-win)
+	    (if(equal walk-win win)
+		(setq visible t)))
+	 nil 'all-screens)
+	visible))
+  )
+
+(defun ediff-submit-report ()
+  "Submit bug report on Ediff."
+  (interactive)
+  (let ((reporter-prompt-for-summary-p t)
+	(ctl-buf ediff-control-buffer)
+	varlist salutation buffer-name)
+    (setq varlist '(ediff-diff-program ediff-diff-options
+		    ediff-patch-program ediff-patch-options
+		    ediff-shell
+		    ediff-use-faces 
+		    ediff-auto-refine ediff-highlighting-style
+		    ediff-buffer-A ediff-buffer-B ediff-control-buffer
+		    ediff-forward-word-function
+		    ediff-control-frame
+		    ediff-control-frame-parameters
+		    ediff-control-frame-position-function
+		    ediff-prefer-iconified-control-frame
+		    ediff-window-setup-function
+		    ediff-split-window-function
+		    ediff-job-name
+		    ediff-word-mode
+		    buffer-name
+		    window-system
+		    ))
+    (setq salutation "
+Congratulations! You may have unearthed a bug in Ediff!
+
+Please make a concise and accurate summary of what happened
+and mail it to the address above.
+-----------------------------------------------------------
+")
+    
+    (ediff-skip-unsuitable-frames)
+    (if window-system
+	(set-mouse-position (ediff-selected-frame) 1 0))
+    
+    (switch-to-buffer ediff-msg-buffer)
+    (erase-buffer)
+    (delete-other-windows)
+    (insert "
+Please read this first:
+----------------------
+
+Some ``bugs'' may actually be no bugs at all. For instance, if you are
+reporting that certain difference regions are not matched as you think they
+should, this is most likely due to the way Unix diff program decides what
+constitutes a difference region. Ediff is an Emacs interface to diff, and
+it has nothing to do with those decisions---it only takes the output from
+diff and presents it in a way that is better suited for human browsing and
+manipulation.
+
+If Emacs happens to dump core, this is NOT an Ediff problem---it is
+an Emacs bug. Report this to Emacs maintainers.
+
+Another popular topic for reports is compilation messages.  Because Ediff
+interfaces to several other packages and runs under Emacs and XEmacs,
+byte-compilation may produce output like this:
+
+       While compiling toplevel forms in file ediff.el:
+	 ** reference to free variable pm-color-alist
+	   ........................
+       While compiling the end of the data:
+	 ** The following functions are not known to be defined: 
+	   ediff-valid-color-p, ediff-display-color-p, ediff-set-face,
+	   ........................
+
+These are NOT errors, but inevitable warnings, which ought to be ignored.
+
+Please do not report those and similar things.  However, comments and
+suggestions are always welcome.
+
+Mail anyway? (y or n) ")
+      
+    (if (y-or-n-p "Mail anyway? ")
+	(progn
+	  (if (ediff-buffer-live-p ctl-buf)
+	      (set-buffer ctl-buf))
+	  (setq buffer-name (buffer-name))
+	  (require 'reporter)
+	  (reporter-submit-bug-report "kifer@cs.sunysb.edu"
+				      (ediff-version)
+				      varlist
+				      nil 
+				      'delete-other-windows
+				      salutation))
+      (bury-buffer)
+      (beep 1)(message "Bug report aborted")
+      (if (ediff-buffer-live-p ctl-buf)
+	  (ediff-eval-in-buffer ctl-buf
+	    (ediff-recenter 'no-rehighlight))))
+    ))
+			     
+       
+(defun ediff-union (list1 list2)
+  "Combine LIST1 and LIST2 using a set-union operation.
+The result list contains all items that appear in either LIST1 or LIST2.
+This is a non-destructive function; it makes a copy of the data if necessary
+to avoid corrupting the original LIST1 and LIST2.
+This is a slightly simplified version from `cl-seq.el'.  Added here to
+avoid loading cl-*."
+  (cond ((null list1) list2) ((null list2) list1)
+	((equal list1 list2) list1)
+	(t
+	 (or (>= (length list1) (length list2))
+	     (setq list1 (prog1 list2 (setq list2 list1))))
+	 (while list2
+	   (or (memq (car list2) list1)
+	       (setq list1 (cons (car list2) list1)))
+	   (setq list2 (cdr list2)))
+	 list1)))
+	 
+(defun ediff-deactivate-mark ()
+  (if ediff-xemacs-p
+	  (zmacs-deactivate-region)
+	(deactivate-mark)))
+
+(cond ((fboundp 'nuke-selective-display)
+       ;; XEmacs 19.12 has nuke-selective-display
+       (fset 'ediff-nuke-selective-display 'nuke-selective-display))
+      (t
+       (defun ediff-nuke-selective-display ()
+	 (save-excursion
+	   (save-restriction
+	     (widen)
+	     (goto-char (point-min))
+	     (let ((mod-p (buffer-modified-p))
+		   (buffer-read-only nil)
+		   end)
+	       (and (eq t selective-display)
+		    (while (search-forward "\^M" nil t)
+		      (end-of-line)
+		      (setq end (point))
+		      (beginning-of-line)
+		      (while (search-forward "\^M" end t)
+			(delete-char -1)
+			(insert "\^J"))))
+	       (set-buffer-modified-p mod-p)
+	       (setq selective-display nil)))))
+       ))
+
+	 
+;; The next two are simplified versions from emerge.el.
+;; VARS must be a list of symbols
+(defun ediff-save-variables (vars)
+  (mapcar (function (lambda (v) (symbol-value v)))
+	  vars))
+(defun ediff-restore-variables (vars values)
+  (while vars
+    (set (car vars) (car values))
+    (setq vars (cdr vars)
+	  values (cdr values))))
+
+;; When Emacs implements before/after-string properties in overlays,
+;; this function will be deleted
+(defun ediff-remember-buffer-characteristics (&optional arg)
+  "Record certain properties of the buffers being compared.
+Must be called in the control buffer.  Saves `read-only', `modified',
+and `auto-save' properties in buffer local variables.  Turns off
+`auto-save-mode'.  These properties are restored via a call to
+`ediff-restore-buffer-characteristics'."
+
+  ;; remember and alter buffer characteristics
+  (set  (if arg 'ediff-buffer-A-values-setup 'ediff-buffer-A-values)
+	(ediff-eval-in-buffer ediff-buffer-A
+	  (prog1
+	      (ediff-save-variables ediff-saved-variables)
+	    (ediff-restore-variables ediff-saved-variables
+				     ediff-working-values))))
+  (set  (if arg 'ediff-buffer-B-values-setup 'ediff-buffer-B-values)
+	(ediff-eval-in-buffer ediff-buffer-B
+	  (prog1
+	      (ediff-save-variables ediff-saved-variables)
+	    (ediff-restore-variables ediff-saved-variables
+				     ediff-working-values))))
+  (if (ediff-buffer-live-p ediff-buffer-C)
+      (set  (if arg 'ediff-buffer-C-values-setup 'ediff-buffer-C-values)
+	    (ediff-eval-in-buffer ediff-buffer-C
+	      (prog1
+		  (ediff-save-variables ediff-saved-variables)
+		(ediff-restore-variables ediff-saved-variables
+					 ediff-working-values)))))
+  )
+  
+;; must execute in control buf
+(defun ediff-save-protected-variables ()
+  (setq ediff-buffer-A-values-orig
+	(ediff-eval-in-buffer ediff-buffer-A
+	  (ediff-save-variables ediff-protected-variables)))
+  (setq ediff-buffer-B-values-orig
+	(ediff-eval-in-buffer ediff-buffer-B
+	  (ediff-save-variables ediff-protected-variables)))
+  (if ediff-3way-comparison-job
+      (setq ediff-buffer-C-values-orig
+	    (ediff-eval-in-buffer ediff-buffer-C
+	      (ediff-save-variables ediff-protected-variables)))))
+
+;; must execute in control buf
+(defun ediff-restore-protected-variables ()
+  (let ((values-A ediff-buffer-A-values-orig)
+	(values-B ediff-buffer-B-values-orig)
+	(values-C ediff-buffer-C-values-orig))
+  (ediff-eval-in-buffer ediff-buffer-A
+    (ediff-restore-variables ediff-protected-variables values-A))
+  (ediff-eval-in-buffer ediff-buffer-B
+    (ediff-restore-variables ediff-protected-variables values-B))
+  (if ediff-3way-comparison-job
+      (ediff-eval-in-buffer ediff-buffer-C
+	(ediff-restore-variables ediff-protected-variables values-C)))))
+
+;; When Emacs implements before/after-string properties in overlays, this
+;; function will be called only once, in ediff-really-quit.
+(defun ediff-restore-buffer-characteristics (&optional arg)
+  "Restore properties saved by `ediff-remember-buffer-characteristics'."
+  (let ((A-values (if arg ediff-buffer-A-values-setup ediff-buffer-A-values))
+	(B-values (if arg ediff-buffer-B-values-setup ediff-buffer-B-values))
+	(C-values (if arg ediff-buffer-C-values-setup ediff-buffer-C-values))
+	)
+	
+    (ediff-eval-in-buffer ediff-buffer-A
+      (ediff-restore-variables ediff-saved-variables A-values))
+    (ediff-eval-in-buffer ediff-buffer-B
+      (ediff-restore-variables ediff-saved-variables B-values))
+    (if (ediff-buffer-live-p ediff-buffer-C)
+	(ediff-eval-in-buffer ediff-buffer-C
+	  (ediff-restore-variables ediff-saved-variables C-values)))
+    ))
+
+
+;;; Debug
+
+(ediff-defvar-local ediff-command-begin-time '(0 0 0) "")
+
+;; calculate time used by command
+(defun ediff-calc-command-time ()
+  (let ((end (current-time))
+	micro sec)
+    (setq micro
+	  (if (>= (nth 2 end) (nth 2 ediff-command-begin-time))
+	      (- (nth 2 end) (nth 2 ediff-command-begin-time))
+	    (+ (nth 2 end) (- 1000000 (nth 2 ediff-command-begin-time)))))
+    (setq sec (- (nth 1 end) (nth 1 ediff-command-begin-time)))
+    (or (equal ediff-command-begin-time '(0 0 0))
+	(message "Elapsed time: %d second(s) + %d microsecond(s)" sec micro))))
+
+(defsubst ediff-save-time ()
+  (setq ediff-command-begin-time (current-time)))
+    
+(defun ediff-profile ()
+  "Toggle profiling Ediff commands."
+  (interactive)
+  (or (ediff-buffer-live-p ediff-control-buffer)
+      (error "This command runs only out of Ediff Control Buffer"))
+  (make-local-variable 'pre-command-hook)
+  (make-local-variable 'post-command-hook)
+  (if (memq 'ediff-save-time pre-command-hook)
+      (progn (remove-hook 'pre-command-hook 'ediff-save-time)
+	     (remove-hook 'post-command-hook 'ediff-calc-command-time)
+	     (setq ediff-command-begin-time '(0 0 0))
+	     (message "Ediff profiling disabled"))
+    (add-hook 'pre-command-hook 'ediff-save-time t)
+    (add-hook 'post-command-hook 'ediff-calc-command-time)
+    (message "Ediff profiling enabled")))
+    
+(defun ediff-print-diff-vector (diff-vector-var)
+  (princ (format "\n*** %S ***\n" diff-vector-var))
+  (mapcar (function
+	   (lambda (overl-vec)
+	     (princ
+	      (format
+	       "Diff %d: \tOverlay:    %S
+\t\tFine diffs: %s
+\t\tNo-fine-diff-flag: %S
+\t\tState-of-diff:\t   %S
+\t\tState-of-merge:\t   %S
+" 
+	       (1+ (ediff-overlay-get (aref overl-vec 0) 'ediff-diff-num))
+	       (aref overl-vec 0)
+	       ;; fine-diff-vector
+	       (if (= (length (aref overl-vec 1)) 0)
+		   "none\n"
+		 (mapconcat 'prin1-to-string
+			    (aref overl-vec 1) "\n\t\t\t    "))
+	       (aref overl-vec 2) ; no fine diff flag
+	       (aref overl-vec 3) ; state-of-diff
+	       (aref overl-vec 4) ; state-of-merge
+	       ))))
+	  (eval diff-vector-var)))
+
+  
+
+(defun ediff-debug-info ()
+  (interactive)
+  (or (ediff-buffer-live-p ediff-control-buffer)
+      (error "This command runs only out of Ediff Control Buffer"))
+  (with-output-to-temp-buffer ediff-debug-buffer
+    (princ (format "\nCtl buffer: %S\n" ediff-control-buffer))
+    (ediff-print-diff-vector (intern (concat "ediff-difference-vector-" "A")))
+    (ediff-print-diff-vector (intern (concat "ediff-difference-vector-" "B")))
+    (ediff-print-diff-vector (intern (concat "ediff-difference-vector-" "C")))
+    ))
+
+;; don't report error if version control package wasn't found
+;;(ediff-load-version-control 'silent)
+
+(run-hooks 'ediff-load-hooks)
+    
+;; to foil foul play
+(if (or (not window-system) 
+	(ediff-check-version '< 19 11 'xemacs))
+    (fset 'ediff-setup-windows-multiframe 'ediff-setup-windows-plain))
+    
+  
+;;; Local Variables:
+;;; eval: (put 'ediff-defvar-local 'lisp-indent-hook 'defun)
+;;; eval: (put 'ediff-eval-in-buffer 'lisp-indent-hook 1)
+;;; End:
+
+(provide 'ediff-util)
+
+;;; ediff-util.el ends here
diff --git a/lisp/ediff-wind.el b/lisp/ediff-wind.el
new file mode 100644
index 00000000000..9ccdc437c97
--- /dev/null
+++ b/lisp/ediff-wind.el
@@ -0,0 +1,1098 @@
+;;; ediff-wind.el --- window manipulation utilities
+;;; Copyright (C) 1994 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+(require 'ediff-init)
+
+
+(defvar ediff-window-setup-function (if (not window-system)
+					'ediff-setup-windows-plain
+				      'ediff-setup-windows-multiframe)
+  "*Function called to set up windows.
+Ediff provides a choice of two functions: ediff-setup-windows-plain, for
+doing everything in one frame, and ediff-setup-windows-multiframe,
+which sets the control panel in a separate frame. Also, if the latter
+function detects that one of the buffers A/B is seen in some other frame,
+it will try to keep that buffer in that frame.
+
+If you don't like the two functions provided---write your own one.
+The basic guidelines:
+    1. It should leave the control buffer current and the control window
+       selected. 
+    2. It should set ediff-window-A, ediff-window-B, ediff-window-C,
+       and ediff-control-window to contain window objects that display
+       the corresponding buffers.
+    3. It should accept the following arguments:
+       buffer-A, buffer-B, buffer-C, control-buffer
+       Buffer C may not be used in jobs that compare only two buffers.
+If you plan to do something fancy, take a close look at how the two
+provided functions are written.")
+
+;; indicates if we are in a multiframe setup
+(ediff-defvar-local ediff-multiframe nil "")
+
+;; Share of the frame occupied by the merge window (buffer C)
+(ediff-defvar-local ediff-merge-window-share 0.45 "")
+
+;; The control window.
+(ediff-defvar-local ediff-control-window nil "")
+;; Official window for buffer A
+(ediff-defvar-local ediff-window-A nil "")
+;; Official window for buffer B
+(ediff-defvar-local ediff-window-B nil "")
+;; Official window for buffer C
+(ediff-defvar-local ediff-window-C nil "")
+;; Ediff's window configuration.
+;; Used to minimize the need to rearrange windows.
+(ediff-defvar-local ediff-window-config-saved "" "")
+
+
+(defvar ediff-split-window-function 'split-window-vertically
+  "*The function used to split the main window between buffer-A and buffer-B.
+You can set it to a horizontal split instead of the default vertical split
+by setting this variable to `split-window-horizontally'.
+You can also have your own function to do fancy splits.
+This variable has no effect when buffer-A/B are shown in different frames.
+In this case, Ediff will use those frames to display these buffers.")
+
+(defvar ediff-merge-split-window-function 'split-window-horizontally
+  "*The function used to split the main window between buffer-A and buffer-B.
+You can set it to a vertical split instead of the default horizontal split
+by setting this variable to `split-window-vertically'.
+You can also have your own function to do fancy splits.
+This variable has no effect when buffer-A/B/C are shown in different frames.
+In this case, Ediff will use those frames to display these buffers.")
+
+(defconst ediff-control-frame-parameters
+  (if window-system
+      (list 
+       '(name . "Ediff")
+       ;;'(unsplittable . t)
+       '(minibuffer . nil)
+       '(vertical-scroll-bars . nil)  ; FSF only
+       '(scrollbar-width . 0)         ; XEmacs only
+       '(menu-bar-lines . 0)          ; FSF only
+       ;; don't lower and auto-raise
+       '(auto-lower . nil)
+       '(auto-raise . t)
+       ;; this blocks queries from  window manager as to where to put
+       ;; ediff's control frame. we put the frame outside the display,
+       ;; so the initial frame won't jump all over the screen
+       (cons 'top  (if (fboundp 'x-display-pixel-height)
+		       (1+ (x-display-pixel-height))
+		     3000))
+       (cons 'left (if (fboundp 'x-display-pixel-width)
+		       (1+ (x-display-pixel-width))
+		     3000))
+       ))
+  "Frame parameters for displaying Ediff Control Panel.
+Do not specify width and height here. These are computed automatically.")
+
+(defvar ediff-control-frame-position-function 'ediff-make-frame-position
+  "Function to call to determine the desired location for the control panel.
+Expects three parameters: the control buffer, the desired width and height
+of the control frame. It returns an association list
+of the form \(\(top . <position>\) \(left . <position>\)\)")
+
+(defvar ediff-control-frame-upward-shift (if ediff-xemacs-p 36 4)
+  "*The upward shift of control frame from the top of buffer A's frame.
+Measured in pixels.
+This is used by the default control frame positioning function,
+`ediff-make-frame-position'. This variable is provided for easy
+customization of the default.")
+
+(defvar ediff-narrow-control-frame-leftward-shift (if ediff-xemacs-p 7 3)
+  "*The leftward shift of control frame from the right edge of buf A's frame.
+Measured in characters.
+This is used by the default control frame positioning function,
+`ediff-make-frame-position' to adjust the position of the control frame
+when it shows the short menu. This variable is provided for easy
+customization of the default.")
+
+(defvar ediff-wide-control-frame-rightward-shift 7
+  "*The rightward shift of control frame from the left edge of buf A's frame.
+Measured in characters.
+This is used by the default control frame positioning function,
+`ediff-make-frame-position' to adjust the position of the control frame
+when it shows the full menu. This variable is provided for easy
+customization of the default.")
+
+
+;; Wide frame display
+
+;; t means Ediff is using wide display
+(ediff-defvar-local ediff-wide-display-p nil "")
+;; keeps frame config for toggling wide display
+(ediff-defvar-local ediff-wide-display-orig-parameters nil 
+  "Frame parameters to be restored when the user wants to toggle the wide
+display off.")
+(ediff-defvar-local ediff-wide-display-frame nil
+  "Frame to be used for wide display.")
+(ediff-defvar-local ediff-make-wide-display-function 'ediff-make-wide-display
+  "The value is a function that is called to create a wide display.
+The function is called without arguments. It should resize the frame in
+which buffers A, B, and C are to be displayed, and it should save the old
+frame parameters in `ediff-wide-display-orig-parameters'.
+The variable `ediff-wide-display-frame' should be set to contain
+the frame used for the wide display.")
+
+;; Frame used for the control panel in a windowing system.
+(ediff-defvar-local ediff-control-frame nil "")
+
+(defvar ediff-prefer-iconified-control-frame nil
+  "*If t, keep control panel iconified when help message is off.
+This has effect only on a windowing system.
+If t, hiting `?' to toggle control panel off iconifies it.
+
+This is only useful in Emacs and only for certain kinds of window managers,
+such as TWM and its derivatives, since the window manager must permit
+keyboard input to go into icons. XEmacs completely ignores keyboard input
+into icons, regardless of the window manager.")
+
+;;; Functions
+
+(defun ediff-get-window-by-clicking (wind prev-wind wind-number)
+  (let (event)
+    (message
+     "Select windows by clicking. Please click on Window %d " wind-number)
+    (while (not (ediff-mouse-event-p (setq event (ediff-read-event))))
+      (if (sit-for 1) ; if sequence of events, wait till the final word
+	  (beep 1))
+      (message "Please click on Window %d " wind-number))
+    (ediff-read-event) ; discard event
+    (setq wind (if ediff-xemacs-p
+		   (event-window event)
+		 (posn-window (event-start event))))
+    ))
+      
+
+;; Select the lowest window on the frame.
+(defun ediff-select-lowest-window ()
+  (let* ((lowest-window (selected-window))
+	 (bottom-edge (car (cdr (cdr (cdr (window-edges))))))
+	 ;;(last-window (previous-window))
+         (last-window (save-excursion
+			(other-window -1) (selected-window)))
+         (window-search t))
+    (while window-search
+      (let* ((this-window (next-window))
+             (next-bottom-edge (car (cdr (cdr (cdr 
+                                               (window-edges this-window)))))))
+        (if (< bottom-edge next-bottom-edge)
+            (progn
+              (setq bottom-edge next-bottom-edge)
+              (setq lowest-window this-window)))
+
+        (select-window this-window)
+        (if (eq last-window this-window)
+            (progn
+              (select-window lowest-window)
+              (setq window-search nil)))))))
+
+ 
+
+;;; Common window setup routines
+
+;; Set up the window configuration.  If POS is given, set the points to
+;; the beginnings of the buffers.
+;; When 3way comparison is added, this will have to choose the appropriate
+;; setup function based on ediff-job-name
+(defun ediff-setup-windows (buffer-A buffer-B buffer-C control-buffer)
+  ;; Make sure we are not in the minibuffer window when we try to delete
+  ;; all other windows.
+  (run-hooks 'ediff-before-setup-windows-hooks)
+  (if (eq (selected-window) (minibuffer-window))
+      (other-window 1))
+      
+  ;; when support for buf C is added, the actual window setup function will
+  ;; depend on ediff-job-name
+  (or (ediff-keep-window-config control-buffer)
+      (funcall 
+       (ediff-eval-in-buffer control-buffer ediff-window-setup-function)
+       buffer-A buffer-B buffer-C control-buffer))
+  (run-hooks 'ediff-after-setup-windows-hooks))
+
+;; Just set up 3 windows.
+;; Usually used without windowing systems
+;; With windowing, we want to use dedicated frames.
+(defun ediff-setup-windows-plain (buffer-A buffer-B buffer-C control-buffer)
+  (ediff-eval-in-buffer control-buffer
+    (setq ediff-multiframe nil))
+  (if ediff-merge-job
+      (ediff-setup-windows-plain-merge
+       buffer-A buffer-B buffer-C control-buffer)
+    (ediff-setup-windows-plain-compare 
+     buffer-A buffer-B buffer-C control-buffer)))
+     
+(defun ediff-setup-windows-plain-merge (buf-A buf-B buf-C control-buffer)
+    ;; skip dedicated and unsplittable frames
+  (ediff-eval-in-buffer control-buffer
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(progn
+	  (redraw-display)
+	  (ediff-delete-frame ediff-control-frame)
+	  (setq ediff-control-frame nil))))
+  (ediff-skip-unsuitable-frames)
+  (let ((window-min-height 1)
+	split-window-function 
+	merge-window-share merge-window-lines
+	wind-A wind-B wind-C)
+    (ediff-eval-in-buffer control-buffer
+      (setq merge-window-share ediff-merge-window-share
+	    ;; this lets us have local versions of ediff-split-window-function
+	    split-window-function ediff-split-window-function))
+    (delete-other-windows)
+    (split-window-vertically)
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    
+    ;; go to the upper window and split it betw A, B, and possibly C
+    (other-window 1) 
+    (setq merge-window-lines
+	  (max 2 (round (* (window-height) merge-window-share))))
+    (switch-to-buffer buf-A)
+    (setq wind-A (selected-window))
+    
+    ;; XEmacs seems to have a lot of trouble with display
+    ;; It won't set things right unless we tell it to sit still
+    (if ediff-xemacs-p (sit-for 0))
+    
+    (split-window-vertically (max 2 (- (window-height) merge-window-lines)))
+    (if (eq (selected-window) wind-A) 
+	(other-window 1))
+    (setq wind-C (selected-window))
+    (switch-to-buffer buf-C)
+    
+    (select-window wind-A)
+    (funcall split-window-function)
+		  
+    (if (eq (selected-window) wind-A)
+	(other-window 1))
+    (switch-to-buffer buf-B)
+    (setq wind-B (selected-window))
+	  
+    (ediff-eval-in-buffer control-buffer
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C))
+    
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    ))
+
+     
+;; This function handles all comparison jobs, including 3way jobs
+(defun ediff-setup-windows-plain-compare (buf-A buf-B buf-C control-buffer)
+  ;; skip dedicated and unsplittable frames
+  (ediff-eval-in-buffer control-buffer
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(progn
+	  (redraw-display)
+	  (ediff-delete-frame ediff-control-frame)
+	  (setq ediff-control-frame nil))))
+  (ediff-skip-unsuitable-frames)
+  (let ((window-min-height 1)
+	split-window-function wind-width-or-height
+	three-way-comparison
+	job wind-A-start wind-B-start wind-A wind-B wind-C)
+    (ediff-eval-in-buffer control-buffer
+      (setq wind-A-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'A ediff-narrow-bounds))
+	    wind-B-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'B  ediff-narrow-bounds))
+	    job ediff-job-name
+	    ;; this lets us have local versions of ediff-split-window-function
+	    split-window-function ediff-split-window-function
+	    three-way-comparison ediff-3way-comparison-job))
+    (delete-other-windows)
+    (split-window-vertically)
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    
+    ;; go to the upper window and split it betw A, B, and possibly C
+    (other-window 1) 
+    (switch-to-buffer buf-A)
+    (setq wind-A (selected-window))
+    (if three-way-comparison
+	(setq wind-width-or-height
+	      (/ (if (eq split-window-function 'split-window-vertically)
+		     (window-height wind-A)
+		   (window-width wind-A))
+		 3)))
+    
+    ;; XEmacs seems to have a lot of trouble with display
+    ;; It won't set things right unless we tell it to sit still
+    (if ediff-xemacs-p (sit-for 0))
+    
+    (funcall split-window-function wind-width-or-height)
+		  
+    (if (eq (selected-window) wind-A)
+	(other-window 1))
+    (switch-to-buffer buf-B)
+    (setq wind-B (selected-window))
+	  
+    (if three-way-comparison
+	(progn
+	  (funcall split-window-function) ; equally
+	  (if (eq (selected-window) wind-B)
+	      (other-window 1))
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))))
+	  
+    (ediff-eval-in-buffer control-buffer
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C))
+    
+    ;; It is unlikely that we will want to implement 3way window comparison.
+    ;; So, only buffers A and B are used here.
+    (if (eq job 'ediff-windows)
+	(progn
+	  (set-window-start wind-A wind-A-start)
+	  (set-window-start wind-B wind-B-start)))
+  
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    ))
+
+    
+;; dispatch the appropriate window setup function
+(defun ediff-setup-windows-multiframe (buf-A buf-B buf-C control-buf)
+  (ediff-eval-in-buffer control-buf
+    (setq ediff-multiframe t))
+  (if ediff-merge-job
+      (ediff-setup-windows-multiframe-merge buf-A buf-B buf-C control-buf)
+    (ediff-setup-windows-multiframe-compare buf-A buf-B buf-C control-buf)))
+    
+(defun ediff-setup-windows-multiframe-merge (buf-A buf-B buf-C control-buf)
+;;; Algorithm:
+;;;   If A and B are in the same frame but C's frame is different--- use one
+;;;   frame for A and B and use a separate frame for C. 
+;;;   If C's frame is non-existent, then: if the first suitable
+;;;   non-dedicated frame  is different from A&B's, then use it for C.
+;;;   Otherwise, put A,B, and C in one frame.
+;;;   If buffers A, B, C are is separate frames, use them to display these
+;;;   buffers.
+
+  ;;   Skip dedicated or iconified frames.  Unsplittable frames are taken
+  ;;   care of later.
+  (ediff-skip-unsuitable-frames 'ok-unsplittable)
+  
+  (let* ((window-min-height 1)
+	 (wind-A (ediff-get-visible-buffer-window buf-A))
+	 (wind-B (ediff-get-visible-buffer-window buf-B))
+	 (wind-C (ediff-get-visible-buffer-window buf-C))
+	 (frame-A (if wind-A (ediff-window-frame wind-A)))
+	 (frame-B (if wind-B (ediff-window-frame wind-B)))
+	 (frame-C (if wind-C (ediff-window-frame wind-C)))
+	 ;; on wide display, do things in one frame
+	 (force-one-frame 
+	  (ediff-eval-in-buffer control-buf ediff-wide-display-p))
+	 ;; this lets us have local versions of ediff-split-window-function
+	 (split-window-function 
+	  (ediff-eval-in-buffer control-buf ediff-split-window-function))
+	 (orig-wind (selected-window))
+	 (orig-frame (ediff-selected-frame))
+	 (use-same-frame (or force-one-frame
+			     (eq frame-A (or frame-C orig-frame))
+			     (eq frame-B (or frame-C orig-frame))
+			     (not (ediff-frame-live-p frame-A))
+			     (not (ediff-frame-live-p frame-B))
+			     ))
+	 (use-same-frame-for-AB (and (not use-same-frame)
+				     (eq frame-A frame-B)))
+	 (merge-window-share (ediff-eval-in-buffer control-buf
+			       ediff-merge-window-share))
+	 merge-window-lines
+	 designated-minibuffer-frame
+	 done-A done-B done-C)
+    
+    ;; buf-A on its own
+    (if (and (window-live-p wind-A)
+	     (null use-same-frame)
+	     (null use-same-frame-for-AB))
+	(progn
+	  (select-window wind-A)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  (setq done-A t)))
+    
+    ;; buf-B on its own
+    (if (and (window-live-p wind-B) (null use-same-frame)) ; buf B on its own
+	(progn
+	  (select-window wind-B)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  (setq done-B t)))
+	  
+    ;; buf-C on its own
+    (if (and (window-live-p wind-C) (null use-same-frame)) ; buf C on its own
+	(progn
+	  (select-window wind-C)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))
+	  (setq done-C t)))
+    
+    (if use-same-frame-for-AB
+	(progn 
+	  (ediff-select-frame frame-A)
+	  (switch-to-buffer buf-A)
+	  (delete-other-windows)
+	  (setq wind-A (selected-window))
+	  
+	  (funcall split-window-function)
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  
+	  (setq done-A t
+		done-B t)))
+    
+    (if use-same-frame
+	(let ((curr-frame (ediff-selected-frame))
+	      (window-min-height 1))
+	  ;; avoid dedicated and non-splittable windows
+	  (ediff-skip-unsuitable-frames)
+	  (or (eq curr-frame (ediff-selected-frame))
+	      (setq wind-A nil
+		    wind-B nil
+		    wind-C nil
+		    orig-wind (selected-window)))
+
+	  ;; set the right frame
+	  (cond (wind-A (select-window wind-A))
+		(wind-B (select-window wind-B))
+		(wind-C (select-window wind-C))
+		(t (select-window orig-wind)))
+	  (delete-other-windows)
+	  (setq merge-window-lines
+		(max 2 (round (* (window-height) merge-window-share))))
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  
+	  ;; XEmacs seems to have a lot of trouble with display
+	  ;; It won't set things right unless we tell it to catch breath
+	  (if ediff-xemacs-p (sit-for 0))
+	  
+	  (split-window-vertically
+	   (max 2 (- (window-height) merge-window-lines)))
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (setq wind-C (selected-window))
+	  (switch-to-buffer buf-C)
+	  
+	  (select-window wind-A)
+	  
+	  (funcall split-window-function)
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  
+	  (setq done-A t
+		done-B t
+		done-C t)
+	  ))
+    
+    (or done-A  ; Buf A to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  ))
+    (or done-B  ; Buf B to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  ))
+    
+    (or done-C  ; Buf C to be set in its own frame.
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))
+	  ))
+    
+    (ediff-eval-in-buffer control-buf
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C)
+	    
+      (setq frame-A (ediff-window-frame ediff-window-A)
+	    designated-minibuffer-frame (ediff-window-frame
+					 (minibuffer-window frame-A)))
+      (if ediff-xemacs-p
+	  ()
+	(if (not (eq designated-minibuffer-frame default-minibuffer-frame))
+	    (progn
+	      (setq default-minibuffer-frame designated-minibuffer-frame)
+	      (if (ediff-frame-live-p ediff-control-frame)
+		  (ediff-delete-frame ediff-control-frame)))
+	  ))
+      )
+    
+    (ediff-setup-control-frame control-buf)
+    ))
+
+  
+;; Window setup for all comparison jobs, including 3way comparisons
+(defun ediff-setup-windows-multiframe-compare (buf-A buf-B buf-C control-buf)
+;;; Algorithm:
+;;;    If a buffer is seen in a frame, use that frame for that buffer.  
+;;;    If it is not seen, use the current frame.
+;;;    If both buffers are not seen, they share the current frame.  If one
+;;;    of the buffers is not seen, it is placed in the current frame (where
+;;;    ediff started). If that frame is displaying the other buffer, it is
+;;;    shared between the two buffers.
+;;;    However, if we decide to put both buffers in one frame
+;;;    and the selected frame isn't splittable, we create a new frame and
+;;;    put both buffers there, event if one of this buffers is visible in
+;;;    another frame.
+  
+  ;; Skip dedicated or iconified frames.
+  ;; Unsplittable frames are taken care of later.
+  (ediff-skip-unsuitable-frames 'ok-unsplittable)
+  
+  (let* ((window-min-height 1)
+	 (wind-A (ediff-get-visible-buffer-window buf-A))
+	 (wind-B (ediff-get-visible-buffer-window buf-B))
+	 (wind-C (ediff-get-visible-buffer-window buf-C))
+	 (frame-A (if wind-A (ediff-window-frame wind-A)))
+	 (frame-B (if wind-B (ediff-window-frame wind-B)))
+	 (frame-C (if wind-C (ediff-window-frame wind-C)))
+	 (ctl-frame-exists-p (ediff-eval-in-buffer control-buf
+			       (ediff-frame-live-p ediff-control-frame)))
+	 ;; on wide display, do things in one frame
+	 (force-one-frame 
+	  (ediff-eval-in-buffer control-buf ediff-wide-display-p))
+	 ;; this lets us have local versions of ediff-split-window-function
+	 (split-window-function 
+	  (ediff-eval-in-buffer control-buf ediff-split-window-function))
+	 (three-way-comparison
+	  (ediff-eval-in-buffer control-buf ediff-3way-comparison-job))
+	 (orig-wind (selected-window))
+	 (use-same-frame (or force-one-frame
+			     (eq frame-A frame-B)
+			     (if three-way-comparison
+				 (or (eq frame-A frame-C)
+				     (eq frame-B frame-C)
+				     (not (ediff-frame-live-p frame-A))
+				     (not (ediff-frame-live-p frame-B))
+				     (not (ediff-frame-live-p frame-C))))
+			     (and (not (ediff-frame-live-p frame-B))
+				  (or ctl-frame-exists-p
+				      (eq frame-A (ediff-selected-frame))))
+			     (and (not (ediff-frame-live-p frame-A))
+				  (or ctl-frame-exists-p
+				      (eq frame-B (ediff-selected-frame))))))
+	 wind-A-start wind-B-start job-name
+	 designated-minibuffer-frame
+	 done-A done-B done-C)
+    
+    (ediff-eval-in-buffer control-buf
+      (setq wind-A-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'A ediff-narrow-bounds))
+	    wind-B-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'B ediff-narrow-bounds))
+	    job-name ediff-job-name))
+    
+    (if (and (window-live-p wind-A) (null use-same-frame)) ; buf-A on its own
+	(progn
+	  (select-window wind-A)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  (setq done-A t)))
+    
+    (if (and (window-live-p wind-B) (null use-same-frame)) ; buf B on its own
+	(progn
+	  (select-window wind-B)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  (setq done-B t)))
+	  
+    (if (and (window-live-p wind-C) (null use-same-frame)) ; buf C on its own
+	(progn
+	  (select-window wind-C)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))
+	  (setq done-C t)))
+    
+    (if use-same-frame
+	(let ((curr-frame (ediff-selected-frame))
+	      ;; this affects 3way setups only
+	      wind-width-or-height)
+	  ;; avoid dedicated and non-splittable windows
+	  (ediff-skip-unsuitable-frames)
+	  (or (eq curr-frame (ediff-selected-frame))
+	      (setq wind-A nil
+		    wind-B nil
+		    wind-C nil
+		    orig-wind (selected-window)))
+
+	  ;; set the right frame
+	  (cond (wind-A (select-window wind-A))
+		(wind-B (select-window wind-B))
+		(wind-C (select-window wind-C))
+		(t (select-window orig-wind)))
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  
+	  ;; XEmacs seems to have a lot of trouble with display
+	  ;; It won't set things right unless we tell it to catch breath
+	  (if ediff-xemacs-p (sit-for 0))
+	  
+	  (if three-way-comparison
+	      (setq wind-width-or-height
+		    (/
+		     (if (eq split-window-function 'split-window-vertically)
+			 (window-height wind-A)
+		       (window-width wind-A))
+		     3)))
+	  
+	  (funcall split-window-function wind-width-or-height)
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  
+	  (if three-way-comparison
+	      (progn
+		(funcall split-window-function) ; equally
+		(if (memq (selected-window) (list wind-A wind-B))
+		    (other-window 1))
+		(switch-to-buffer buf-C)
+		(setq wind-C (selected-window))))
+	  (setq done-A t
+		done-B t
+		done-C t)
+	  ))
+    
+    (or done-A  ; Buf A to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  ))
+    (or done-B  ; Buf B to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  ))
+    
+    (if three-way-comparison
+	(or done-C  ; Buf C to be set in its own frame
+	    (progn  ; It was not set up yet as it wasn't visible
+	      (select-window orig-wind)
+	      (delete-other-windows)
+	      (switch-to-buffer buf-C)
+	      (setq wind-C (selected-window))
+	      )))
+    
+    (ediff-eval-in-buffer control-buf
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C)
+	    
+      (setq frame-A (ediff-window-frame ediff-window-A)
+	    designated-minibuffer-frame (ediff-window-frame
+					 (minibuffer-window frame-A)))
+      (if ediff-xemacs-p
+	  ()
+	(if (not (eq designated-minibuffer-frame default-minibuffer-frame))
+	    (progn
+	      (setq default-minibuffer-frame designated-minibuffer-frame)
+	      (if (ediff-frame-live-p ediff-control-frame)
+		  (ediff-delete-frame ediff-control-frame)))
+	  ))
+      )
+    
+    ;; It is unlikely that we'll implement ediff-windows that would compare
+    ;; 3 windows at once. So, we don't use buffer C here.
+    (if (eq job-name 'ediff-windows)
+	(progn
+	  (set-window-start wind-A wind-A-start)
+	  (set-window-start wind-B wind-B-start)))
+    
+    (ediff-setup-control-frame control-buf)
+    ))
+
+;; skip unsplittable and dedicated windows
+;; create a new splittable frame if none is found
+(defun ediff-skip-unsuitable-frames (&optional ok-unsplittable)
+  (if window-system
+      (let (last-window)
+	(while (and (not (eq (selected-window) last-window))
+		    (or
+		     (window-dedicated-p (selected-window))
+		     (ediff-frame-iconified-p (ediff-selected-frame))
+		     (if ok-unsplittable
+			 nil
+		       (ediff-frame-unsplittable-p (ediff-selected-frame)))))
+	  ;; remember where started
+	  (or last-window (setq last-window (selected-window)))
+	  ;; try new window
+	  (other-window 1 t))
+	(if (eq (selected-window) last-window)
+	    ;; fed up, no appropriate frame
+	    (progn
+	      (redraw-display)
+	      (ediff-select-frame (ediff-make-frame '((unsplittable)))))))))
+
+;; Prepare or refresh control frame
+(defun ediff-setup-control-frame (ctl-buffer)
+  (let ((window-min-height 1)
+	ctl-frame-iconified-p dont-iconify-ctl-frame deiconify-ctl-frame
+	ctl-frame old-ctl-frame lines 
+	fheight fwidth adjusted-parameters) 
+	
+    (ediff-eval-in-buffer ctl-buffer
+      (run-hooks 'ediff-before-setup-control-frame-hooks))
+  
+    (setq old-ctl-frame (ediff-eval-in-buffer ctl-buffer ediff-control-frame))
+    (if (ediff-frame-live-p old-ctl-frame)
+	(setq ctl-frame old-ctl-frame)
+      (redraw-display)
+      ;; frame should be made while ctl-buff is current, so that
+      ;; the local default-minibuffer-frame will be consulted and
+      ;; that ediff-control-frame-parameters will have the right value.
+      (ediff-eval-in-buffer ctl-buffer
+	(setq ctl-frame (ediff-make-frame 
+			 ediff-control-frame-parameters)))
+      (ediff-eval-in-buffer ctl-buffer (setq ediff-control-frame ctl-frame)))
+    
+    (setq ctl-frame-iconified-p (ediff-frame-iconified-p ctl-frame))
+    (ediff-select-frame ctl-frame)
+    (if (window-dedicated-p (selected-window))
+	()
+      (delete-other-windows)
+      (switch-to-buffer ctl-buffer))
+      
+    ;; must be before ediff-setup-control-buffer
+    (if ediff-xemacs-p
+	;; just a precaution--we should be in ctl-buffer already
+	(ediff-eval-in-buffer ctl-buffer
+	  (make-local-variable 'screen-title-format)
+	  (make-local-variable 'screen-icon-title-format)))
+    
+    (ediff-setup-control-buffer ctl-buffer)
+    (setq dont-iconify-ctl-frame
+	  (not (string= ediff-help-message ediff-brief-help-message)))
+    (setq deiconify-ctl-frame 
+	  (and (eq this-command 'ediff-toggle-help)
+	       dont-iconify-ctl-frame))
+    
+    ;; 1 more line for the modeline
+    (setq lines (if ediff-xemacs-p
+		    (+ 2 (count-lines (point-min) (point-max)))
+		  (1+ (count-lines (point-min) (point-max))))
+	  fheight lines
+	  fwidth (+ (ediff-help-message-line-length) 2)
+	  adjusted-parameters (append (list
+				       (cons 'width fwidth)
+				       (cons 'height fheight))
+				      (funcall
+				       ediff-control-frame-position-function
+				       ctl-buffer fwidth fheight)))
+    
+    ;; In XEmacs, buffer menubar needs to be killed before frame parameters
+    ;; are changed XEmacs needs to redisplay, as it has trouble setting
+    ;; height correctly otherwise.
+    (if (and ediff-xemacs-p (ediff-frame-has-menubar))
+	(progn (set-buffer-menubar nil)(sit-for 0)))
+    
+    ;; Under OS/2 (emx) we have to call modify frame parameters twice, in
+    ;; order to make sure that at least once we do it for non-iconified
+    ;; frame. If appears that in the OS/2 port of Emacs, one can't modify
+    ;; frame parameters of iconified frames.
+    (if (eq system-type 'emx)
+	(ediff-modify-frame-parameters ctl-frame adjusted-parameters))
+      
+    (goto-char (point-min))
+    
+    (cond ((and ediff-prefer-iconified-control-frame
+		(not ctl-frame-iconified-p)
+		(not dont-iconify-ctl-frame))
+	   (ediff-iconify-frame ctl-frame))
+	  ((or deiconify-ctl-frame
+	       (not ctl-frame-iconified-p))
+	   (ediff-raise-frame ctl-frame)))
+    
+    ;; This works around a bug in 19.25 and earlier. There, if frame gets
+    ;; iconified, the current buffer changes to that of the frame that
+    ;; becomes exposed as a result of this iconification.
+    ;; So, we make sure the current buffer doesn't change.
+    (ediff-select-frame ctl-frame)
+    (ediff-refresh-control-frame)
+    
+    (ediff-modify-frame-parameters ctl-frame adjusted-parameters)
+    
+    (if ediff-xemacs-p
+	(set-window-buffer-dedicated (selected-window) ctl-buffer)
+      (set-window-dedicated-p (selected-window) t))
+      
+    (or ediff-xemacs-p (sit-for 0 200)) ; emacs has trouble here, needs time
+    (or (ediff-frame-iconified-p ctl-frame)
+	(set-mouse-position ctl-frame 1 0))
+    (if (ediff-check-version '< 19 11 'xemacs) (sit-for 0))
+    (or ediff-xemacs-p (unfocus-frame))
+	
+    (if ediff-xemacs-p
+	(ediff-eval-in-buffer ctl-buffer
+	  (make-local-variable 'select-screen-hook)
+	  (add-hook 'select-screen-hook 'ediff-xemacs-select-screen-hook)
+	  ))
+	
+    (ediff-eval-in-buffer ctl-buffer
+      (run-hooks 'ediff-after-setup-control-frame-hooks))
+  
+    ))	 
+    
+
+;; finds a good place to clip control frame
+(defun ediff-make-frame-position (ctl-buffer ctl-frame-width ctl-frame-height)
+  (ediff-eval-in-buffer ctl-buffer
+    (let* ((frame-A (ediff-window-frame ediff-window-A))
+	   (frame-A-parameters (ediff-frame-parameters frame-A))
+	   (frame-A-top (cdr (assoc 'top frame-A-parameters)))
+	   (frame-A-left (cdr (assoc 'left frame-A-parameters)))
+	   (frame-A-width (ediff-frame-width frame-A))
+	   (ctl-frame ediff-control-frame)
+	   horizontal-adjustment upward-adjustment
+	   ctl-frame-top) 
+      
+      ;; Multiple control frames are clipped based on the value of
+      ;; ediff-control-buffer-number. This is done in order not to obscure
+      ;; other active control panels.
+      (setq horizontal-adjustment (* 2 ediff-control-buffer-number)
+	    upward-adjustment (* -14 ediff-control-buffer-number))
+
+      (setq ctl-frame-top (- frame-A-top
+			     upward-adjustment
+			     ediff-control-frame-upward-shift))
+      (list
+       (cons 'top (if (> ctl-frame-top 0) ctl-frame-top 1))
+       (cons 'left (+ frame-A-left
+		      (if ediff-prefer-long-help-message
+			  (* (ediff-frame-char-width ctl-frame)
+			     (+ ediff-wide-control-frame-rightward-shift
+				horizontal-adjustment))
+			(- (* frame-A-width
+			      (ediff-frame-char-width frame-A))
+			   (* (ediff-frame-char-width ctl-frame)
+			      (+ ctl-frame-width
+				 ediff-narrow-control-frame-leftward-shift
+				 horizontal-adjustment))))))))))
+			       
+(defun ediff-xemacs-select-screen-hook ()
+  (if (equal (ediff-selected-frame) ediff-control-frame)
+      (ediff-raise-frame ediff-control-frame)))
+	
+(defun ediff-make-wide-display ()
+  "Construct an alist of parameters for the wide display.
+Saves the old frame parameters in `ediff-wide-display-orig-parameters'.
+The frame to be resized is kept in `ediff-wide-display-frame'.
+This function modifies only the left margin and the width of the display.
+It assumes that it is called from within the control buffer."
+  (if (not (fboundp 'x-display-pixel-width))
+      (error
+       "Can't determine display width. Please upgrade your version of Emacs"))
+  (let* ((frame-A (ediff-window-frame ediff-window-A))
+	 (frame-A-params (ediff-frame-parameters frame-A))
+	 (cw (ediff-frame-char-width frame-A))
+	 (wd (- (/ (x-display-pixel-width) cw) 5)))
+    (setq ediff-wide-display-orig-parameters 
+	  (list (cons 'left (max 0 (cdr (assoc 'left frame-A-params))))
+		(cons 'width (cdr (assoc 'width frame-A-params))))
+	  ediff-wide-display-frame frame-A)
+    (ediff-modify-frame-parameters frame-A (list (cons 'left cw)
+						 (cons 'width wd)))))
+  
+      
+
+;; Revise the mode line to display which difference we have selected
+;; Also resets modelines of buffers A/B, since they may be clobbered by
+;; anothe invocations of Ediff.
+(defun ediff-refresh-mode-lines ()
+  (let (buf-A-state-diff buf-B-state-diff buf-C-state-diff buf-C-state-merge)
+    
+    (if (ediff-valid-difference-p)
+	(setq
+	 buf-C-state-diff (ediff-get-state-of-diff ediff-current-difference 'C)
+	 buf-C-state-merge (ediff-get-state-of-merge ediff-current-difference)
+	 buf-A-state-diff (ediff-get-state-of-diff ediff-current-difference 'A)
+	 buf-B-state-diff (ediff-get-state-of-diff ediff-current-difference 'B)
+	 buf-A-state-diff (if buf-A-state-diff
+			      (format "[%s] " buf-A-state-diff)
+			    "")
+	 buf-B-state-diff (if buf-B-state-diff
+			      (format "[%s] " buf-B-state-diff)
+			    "")
+	 buf-C-state-diff (if (and (ediff-buffer-live-p ediff-buffer-C)
+				   (or buf-C-state-diff buf-C-state-merge))
+			      (format "[%s%s] "
+				      (or buf-C-state-diff "")
+				      (if buf-C-state-merge
+					  (concat " " buf-C-state-merge)
+					""))
+			    ""))
+      (setq buf-A-state-diff ""
+	    buf-B-state-diff ""
+	    buf-C-state-diff ""))
+    
+    ;; control buffer format
+    (setq mode-line-format
+	  (list (if (ediff-narrow-control-frame-p) "   " "-- ")
+		mode-line-buffer-identification
+		"               Howdy!"))
+    ;; control buffer id
+    (setq mode-line-buffer-identification 
+	  (if (ediff-narrow-control-frame-p)
+	      (ediff-make-narrow-control-buffer-id 'skip-name)
+	    (ediff-make-wide-control-buffer-id)))
+    ;; Force mode-line redisplay
+    (force-mode-line-update)
+    
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(ediff-refresh-control-frame))
+    
+    (ediff-eval-in-buffer ediff-buffer-A
+      (setq ediff-diff-status buf-A-state-diff)
+      (ediff-strip-mode-line-format)
+      (setq mode-line-format
+	    (list " A: " 'ediff-diff-status mode-line-format))
+      (force-mode-line-update))
+    (ediff-eval-in-buffer ediff-buffer-B
+      (setq ediff-diff-status buf-B-state-diff)
+      (ediff-strip-mode-line-format)
+      (setq mode-line-format
+	    (list " B: " 'ediff-diff-status mode-line-format))
+      (force-mode-line-update))
+    (if ediff-3way-job
+	(ediff-eval-in-buffer ediff-buffer-C
+	  (setq ediff-diff-status buf-C-state-diff)
+	  (ediff-strip-mode-line-format)
+	  (setq mode-line-format
+		(list " C: " 'ediff-diff-status mode-line-format))
+	  (force-mode-line-update)))
+    ))
+    
+  
+(defun ediff-refresh-control-frame ()
+  (if ediff-xemacs-p
+      (progn
+	(setq screen-title-format (ediff-make-narrow-control-buffer-id)
+	      screen-icon-title-format (ediff-make-narrow-control-buffer-id))
+	;; this forces update of the screen title
+	(ediff-modify-frame-parameters ediff-control-frame '(())))
+    (ediff-modify-frame-parameters
+     ediff-control-frame
+     (list (cons 'name (ediff-make-narrow-control-buffer-id))))
+     ))
+   
+  
+(defun ediff-make-narrow-control-buffer-id (&optional skip-name)
+  (concat
+   (if skip-name
+       " "
+     (concat
+      (cdr (assoc 'name ediff-control-frame-parameters))
+      ediff-control-buffer-suffix))
+   (cond ((< ediff-current-difference 0) 
+	  (format " _/%d" ediff-number-of-differences))
+	 ((>= ediff-current-difference ediff-number-of-differences)
+	  (format " $/%d" ediff-number-of-differences))
+	 (t
+	  (format " %d/%d"
+		  (1+ ediff-current-difference)
+		  ediff-number-of-differences)))))
+		  
+(defun ediff-make-wide-control-buffer-id ()
+  (cond ((< ediff-current-difference 0)
+	 (list (format "%%b   At start of %d diffs"
+		       ediff-number-of-differences)))
+	((>= ediff-current-difference ediff-number-of-differences)
+	 (list (format "%%b   At end of %d diffs"
+		       ediff-number-of-differences)))
+	(t
+	 (list (format "%%b   diff %d of %d"
+		       (1+ ediff-current-difference)
+		       ediff-number-of-differences)))))
+
+
+
+;; If buff is not live, return nil
+(defun ediff-get-visible-buffer-window (buff)
+  (if (ediff-buffer-live-p buff)
+      (if ediff-xemacs-p
+	  (get-buffer-window buff t)
+	(get-buffer-window buff 'visible))))
+	
+;;; Functions to decide when to redraw windows
+
+  
+(defun ediff-keep-window-config (control-buf)
+  (and (eq control-buf (current-buffer))
+       (/= (buffer-size) 0)
+       (ediff-eval-in-buffer control-buf
+	 (let ((ctl-wind ediff-control-window)
+	       (A-wind ediff-window-A)
+	       (B-wind ediff-window-B)
+	       (C-wind ediff-window-C))
+	  
+	   (and
+	    (ediff-window-visible-p A-wind)
+	    (ediff-window-visible-p B-wind)
+	    ;; if buffer C is defined then take it into account
+	    (or (not ediff-3way-job)
+		(ediff-window-visible-p C-wind))
+	    (eq (window-buffer A-wind) ediff-buffer-A)
+	    (eq (window-buffer B-wind) ediff-buffer-B)
+	    (or (not ediff-3way-job)
+		(eq (window-buffer C-wind) ediff-buffer-C))
+	    (string= ediff-window-config-saved
+		     (format "%S%S%S%S%S"
+			     ctl-wind A-wind B-wind C-wind
+			     ediff-split-window-function)))))))
+
+
+(provide 'ediff-wind)
+
+
+;;; ediff-wind.el ends here