Initial import of the CDE 2.1.30 sources from the Open Group.

cde/lib/tt/demo/CoEd/libCoEd/CoEdChangeHistory.C

@@ -0,0 +1,128 @@
+//%%  (c) Copyright 1993, 1994 Hewlett-Packard Company			
+//%%  (c) Copyright 1993, 1994 International Business Machines Corp.	
+//%%  (c) Copyright 1993, 1994 Sun Microsystems, Inc.			
+//%%  (c) Copyright 1993, 1994 Novell, Inc. 				
+//%%  $XConsortium: CoEdChangeHistory.C /main/3 1995/10/20 17:06:11 rswiston $ 			 				
+/*
+ * CoEdChangeHistory.cc
+ *
+ * Copyright (c) 1991 by Sun Microsystems.  All Rights Reserved.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the names of Sun
+ * Microsystems and its subsidiaries not be used in advertising or
+ * publicity pertaining to distribution of the software without
+ * specific, written prior permission.  Sun Microsystems and its
+ * subsidiaries make no representations about the suitability of this
+ * software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ *
+ * Sun Microsystems and its subsidiaries disclaim all warranties with
+ * regard to this software, including all implied warranties of
+ * merchantability and fitness.  In no event shall Sun Microsystems or
+ * its subsidiaries be liable for any special, indirect or
+ * consequential damages or any damages whatsoever resulting from loss
+ * of use, data or profits, whether in an action of contract,
+ * negligence or other tortious action, arising out of or in
+ * connection with the use or performance of this software.
+ */
+
+#include <string.h>
+#include "CoEdChangeHistory.h"
+
+CoEdChangeHistory::
+CoEdChangeHistory() : CoEdTextChangeList()
+{
+}
+
+void CoEdChangeHistory::
+insert( CoEdTextChange *change )
+{
+	CoEdTextChange *curr = _tail;
+	//
+	// Find the most recent change in the history that the
+	// incoming change knows of.
+	//
+	while (curr != 0) {
+		if (change->knowsOf( *curr )) {
+			break;
+		}
+		curr = curr->_prev;
+	}
+	//
+	// Bump curr to point to the first change that the incoming
+	// change doesn't know of.
+	//
+	if (curr == 0) {
+		curr = _head;
+	} else {
+		curr = curr->_next;
+	}
+	//
+	// The rest of the changes are mutually ignorant with the incoming
+	// change.  Find the first one with a greater site id, and
+	// stick this change in front of it.
+	//
+	while (curr != 0) {
+		if (*change->_causer < *curr->_causer) {
+			break;
+		}
+		curr = curr->_next;
+	}
+	if (curr == 0) {
+		append( change );
+	} else {
+		insertBefore( change, curr );
+	}
+}
+
+CoEdTextChange *CoEdChangeHistory::
+translate( CoEdTextChange &change )
+{
+	_translateOverEarlierChgs( change );
+	return _translateOverLaterChgs( change );
+}
+
+//
+// Modify <change> so that it takes into account any changes ahead of
+// it in the change history that it does not know about.
+//
+void CoEdChangeHistory::
+_translateOverEarlierChgs( CoEdTextChange &change )
+{
+	CoEdTextChange *curr = _head;
+	while (curr != &change) {
+		if (! change.knowsOf( *curr )) {
+			change.translateOver( *curr );
+		}
+		curr = curr->_next;
+	}
+}
+
+//
+// Take <change>, which is assumed to have been inserted into this
+// ChangeHistory, and adjust the remaining changes in the history
+// so that they take into account the change inserted ahead of them.
+// Also, return a new CoEdTextChange that is a translated version
+// of <change>, suitable for application to a textbuffer that
+// has already had the remaining changes in the history applied to it.
+//
+CoEdTextChange *CoEdChangeHistory::
+_translateOverLaterChgs( const CoEdTextChange &change )
+{
+	CoEdTextChange *xlatdChng = new CoEdTextChange( change );
+	if (xlatdChng == 0) {
+		return 0;
+	}
+
+	CoEdTextChange *curr = change._next;
+	while (curr != 0) {
+		curr->interTranslate( *xlatdChng );
+		curr = curr->_next;
+	}
+	return xlatdChng;
+}
+