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 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