78 lines
1.4 KiB
C
78 lines
1.4 KiB
C
|
/*-
|
||
|
|
* Copyright (c) 1992, 1993, 1994
|
||
|
|
* The Regents of the University of California. All rights reserved.
|
||
|
|
* Copyright (c) 1992, 1993, 1994, 1995, 1996
|
||
|
|
* Keith Bostic. All rights reserved.
|
||
|
|
*
|
||
|
|
* See the LICENSE file for redistribution information.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "config.h"
|
||
|
|
|
||
|
|
#ifndef lint
|
||
|
|
static const char sccsid[] = "@(#)ex_undo.c 10.6 (Berkeley) 3/6/96";
|
||
|
|
#endif /* not lint */
|
||
|
|
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <sys/queue.h>
|
||
|
|
|
||
|
|
#include <bitstring.h>
|
||
|
|
#include <limits.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
|
||
|
|
#include "../common/common.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* ex_undo -- u
|
||
|
|
* Undo the last change.
|
||
|
|
*
|
||
|
|
* PUBLIC: int ex_undo __P((SCR *, EXCMD *));
|
||
|
|
*/
|
||
|
|
int
|
||
|
|
ex_undo(sp, cmdp)
|
||
|
|
SCR *sp;
|
||
|
|
EXCMD *cmdp;
|
||
|
|
{
|
||
|
|
EXF *ep;
|
||
|
|
MARK m;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* !!!
|
||
|
|
* Historic undo always set the previous context mark.
|
||
|
|
*/
|
||
|
|
m.lno = sp->lno;
|
||
|
|
m.cno = sp->cno;
|
||
|
|
if (mark_set(sp, ABSMARK1, &m, 1))
|
||
|
|
return (1);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* !!!
|
||
|
|
* Multiple undo isn't available in ex, as there's no '.' command.
|
||
|
|
* Whether 'u' is undo or redo is toggled each time, unless there
|
||
|
|
* was a change since the last undo, in which case it's an undo.
|
||
|
|
*/
|
||
|
|
ep = sp->ep;
|
||
|
|
if (!F_ISSET(ep, F_UNDO)) {
|
||
|
|
F_SET(ep, F_UNDO);
|
||
|
|
ep->lundo = FORWARD;
|
||
|
|
}
|
||
|
|
switch (ep->lundo) {
|
||
|
|
case BACKWARD:
|
||
|
|
if (log_forward(sp, &m))
|
||
|
|
return (1);
|
||
|
|
ep->lundo = FORWARD;
|
||
|
|
break;
|
||
|
|
case FORWARD:
|
||
|
|
if (log_backward(sp, &m))
|
||
|
|
return (1);
|
||
|
|
ep->lundo = BACKWARD;
|
||
|
|
break;
|
||
|
|
case NOTSET:
|
||
|
|
abort();
|
||
|
|
}
|
||
|
|
sp->lno = m.lno;
|
||
|
|
sp->cno = m.cno;
|
||
|
|
return (0);
|
||
|
|
}
|