1 /* $OpenBSD: ex_undo.c,v 1.6 2014/11/12 04:28:41 bentley Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 * Copyright (c) 1992, 1993, 1994, 1995, 1996
7 * Keith Bostic. All rights reserved.
8 *
9 * See the LICENSE file for redistribution information.
10 */
11
12 #include "config.h"
13
14 #include <sys/types.h>
15 #include <sys/queue.h>
16
17 #include <bitstring.h>
18 #include <limits.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21
22 #include "../common/common.h"
23
24 /*
25 * ex_undo -- u
26 * Undo the last change.
27 *
28 * PUBLIC: int ex_undo(SCR *, EXCMD *);
29 */
30 int
ex_undo(SCR * sp,EXCMD * cmdp)31 ex_undo(SCR *sp, EXCMD *cmdp)
32 {
33 EXF *ep;
34 MARK m;
35
36 /*
37 * !!!
38 * Historic undo always set the previous context mark.
39 */
40 m.lno = sp->lno;
41 m.cno = sp->cno;
42 if (mark_set(sp, ABSMARK1, &m, 1))
43 return (1);
44
45 /*
46 * !!!
47 * Multiple undo isn't available in ex, as there's no '.' command.
48 * Whether 'u' is undo or redo is toggled each time, unless there
49 * was a change since the last undo, in which case it's an undo.
50 */
51 ep = sp->ep;
52 if (!F_ISSET(ep, F_UNDO)) {
53 F_SET(ep, F_UNDO);
54 ep->lundo = FORWARD;
55 }
56 switch (ep->lundo) {
57 case BACKWARD:
58 if (log_forward(sp, &m))
59 return (1);
60 ep->lundo = FORWARD;
61 break;
62 case FORWARD:
63 if (log_backward(sp, &m))
64 return (1);
65 ep->lundo = BACKWARD;
66 break;
67 case NOTSET:
68 abort();
69 }
70 sp->lno = m.lno;
71 sp->cno = m.cno;
72 return (0);
73 }
74