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 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