1 /* $NetBSD: ex_undo.c,v 1.3 2014/01/26 21:43:45 christos Exp $ */
2 /*-
3 * Copyright (c) 1992, 1993, 1994
4 * The Regents of the University of California. All rights reserved.
5 * Copyright (c) 1992, 1993, 1994, 1995, 1996
6 * Keith Bostic. All rights reserved.
7 *
8 * See the LICENSE file for redistribution information.
9 */
10
11 #include "config.h"
12
13 #include <sys/cdefs.h>
14 #if 0
15 #ifndef lint
16 static const char sccsid[] = "Id: ex_undo.c,v 10.7 2001/06/25 15:19:21 skimo Exp (Berkeley) Date: 2001/06/25 15:19:21 ";
17 #endif /* not lint */
18 #else
19 __RCSID("$NetBSD: ex_undo.c,v 1.3 2014/01/26 21:43:45 christos Exp $");
20 #endif
21
22 #include <sys/types.h>
23 #include <sys/queue.h>
24
25 #include <bitstring.h>
26 #include <limits.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29
30 #include "../common/common.h"
31
32 /*
33 * ex_undo -- u
34 * Undo the last change.
35 *
36 * PUBLIC: int ex_undo __P((SCR *, EXCMD *));
37 */
38 int
ex_undo(SCR * sp,EXCMD * cmdp)39 ex_undo(SCR *sp, EXCMD *cmdp)
40 {
41 EXF *ep;
42 MARK m;
43
44 /*
45 * !!!
46 * Historic undo always set the previous context mark.
47 */
48 m.lno = sp->lno;
49 m.cno = sp->cno;
50 if (mark_set(sp, ABSMARK1, &m, 1))
51 return (1);
52
53 /*
54 * !!!
55 * Multiple undo isn't available in ex, as there's no '.' command.
56 * Whether 'u' is undo or redo is toggled each time, unless there
57 * was a change since the last undo, in which case it's an undo.
58 */
59 ep = sp->ep;
60 if (!F_ISSET(ep, F_UNDO)) {
61 F_SET(ep, F_UNDO);
62 ep->lundo = FORWARD;
63 }
64 switch (ep->lundo) {
65 case BACKWARD:
66 if (log_forward(sp, &m))
67 return (1);
68 ep->lundo = FORWARD;
69 break;
70 case FORWARD:
71 if (log_backward(sp, &m))
72 return (1);
73 ep->lundo = BACKWARD;
74 break;
75 case NOTSET:
76 abort();
77 }
78 sp->lno = m.lno;
79 sp->cno = m.cno;
80 return (0);
81 }
82