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