Files
cdesktop/cde/lib/tt/demo/CoEd/libCoEd/CoEdChangeHistory.C
2012-03-10 18:58:32 +00:00

151 lines
4.6 KiB
C

/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these librararies and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
//%% (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;
}