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 #include <sys/types.h> 13 #include <sys/queue.h> 14 #include <sys/time.h> 15 16 #include <bitstring.h> 17 #include <limits.h> 18 #include <stdio.h> 19 #include <stdlib.h> 20 21 #include "../common/common.h" 22 23 /* 24 * ex_undo -- u 25 * Undo the last change. 26 * 27 * PUBLIC: int ex_undo(SCR *, EXCMD *); 28 */ 29 int 30 ex_undo(SCR *sp, EXCMD *cmdp) 31 { 32 EXF *ep; 33 MARK m; 34 35 /* 36 * !!! 37 * Historic undo always set the previous context mark. 38 */ 39 m.lno = sp->lno; 40 m.cno = sp->cno; 41 if (mark_set(sp, ABSMARK1, &m, 1)) 42 return (1); 43 44 /* 45 * !!! 46 * Multiple undo isn't available in ex, as there's no '.' command. 47 * Whether 'u' is undo or redo is toggled each time, unless there 48 * was a change since the last undo, in which case it's an undo. 49 */ 50 ep = sp->ep; 51 if (!F_ISSET(ep, F_UNDO)) { 52 F_SET(ep, F_UNDO); 53 ep->lundo = FORWARD; 54 } 55 switch (ep->lundo) { 56 case BACKWARD: 57 if (log_forward(sp, &m)) 58 return (1); 59 ep->lundo = FORWARD; 60 break; 61 case FORWARD: 62 if (log_backward(sp, &m)) 63 return (1); 64 ep->lundo = BACKWARD; 65 break; 66 case NOTSET: 67 abort(); 68 } 69 sp->lno = m.lno; 70 sp->cno = m.cno; 71 return (0); 72 } 73