1 /* $OpenBSD: ex_undo.c,v 1.5 2009/10/27 23:59:47 deraadt 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(sp,cmdp)31 ex_undo(sp, cmdp)
32 SCR *sp;
33 EXCMD *cmdp;
34 {
35 EXF *ep;
36 MARK m;
37
38 /*
39 * !!!
40 * Historic undo always set the previous context mark.
41 */
42 m.lno = sp->lno;
43 m.cno = sp->cno;
44 if (mark_set(sp, ABSMARK1, &m, 1))
45 return (1);
46
47 /*
48 * !!!
49 * Multiple undo isn't available in ex, as there's no '.' command.
50 * Whether 'u' is undo or redo is toggled each time, unless there
51 * was a change since the last undo, in which case it's an undo.
52 */
53 ep = sp->ep;
54 if (!F_ISSET(ep, F_UNDO)) {
55 F_SET(ep, F_UNDO);
56 ep->lundo = FORWARD;
57 }
58 switch (ep->lundo) {
59 case BACKWARD:
60 if (log_forward(sp, &m))
61 return (1);
62 ep->lundo = FORWARD;
63 break;
64 case FORWARD:
65 if (log_backward(sp, &m))
66 return (1);
67 ep->lundo = BACKWARD;
68 break;
69 case NOTSET:
70 abort();
71 }
72 sp->lno = m.lno;
73 sp->cno = m.cno;
74 return (0);
75 }
76