vi/v_undo.c

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * %sccs.include.redist.c%
   6  */
   7
   8 #ifndef lint
   9 static char sccsid[] = "$Id: v_undo.c,v 8.1 1993/06/09 22:28:33 bostic Exp $ (Berkeley) $Date: 1993/06/09 22:28:33 $";
  10 #endif /* not lint */
  11
  12 #include <sys/types.h>
  13
  14 #include <errno.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17
  18 #include "vi.h"
  19 #include "vcmd.h"
  20
  21 /*
  22  * v_Undo -- U
  23  *      Undo changes to this line, or roll forward.
  24  *
  25  *      Historic vi moved the cursor to the first non-blank character
  26  *      of the line when this happened.  We do not, since we know where
  27  *      the cursor actually was when the changes began.
  28  */
  29 int
  30 v_Undo(sp, ep, vp, fm, tm, rp)
  31         SCR *sp;
  32         EXF *ep;
  33         VICMDARG *vp;
  34         MARK *fm, *tm, *rp;
  35 {
  36         if (O_ISSET(sp, O_NUNDO))
  37                 return (log_forward(sp, ep, rp));
  38         return (log_setline(sp, ep, rp));
  39 }
  40
  41 /*
  42  * v_undo -- u
  43  *      Undo the last change.
  44  */
  45 int
  46 v_undo(sp, ep, vp, fm, tm, rp)
  47         SCR *sp;
  48         EXF *ep;
  49         VICMDARG *vp;
  50         MARK *fm, *tm, *rp;
  51 {
  52         if (O_ISSET(sp, O_NUNDO))
  53                 return (log_backward(sp, ep, rp));
  54
  55         if (!F_ISSET(ep, F_UNDO)) {
  56                 ep->lundo = UFORWARD;
  57                 F_SET(ep, F_UNDO);
  58         }
  59
  60         switch (ep->lundo) {
  61         case UBACKWARD:
  62                 if (log_forward(sp, ep, rp)) {
  63                         F_CLR(ep, F_UNDO);
  64                         return (1);
  65                 }
  66                 ep->lundo = UFORWARD;
  67                 break;
  68         case UFORWARD:
  69                 if (log_backward(sp, ep, rp)) {
  70                         F_CLR(ep, F_UNDO);
  71                         return (1);
  72                 }
  73                 ep->lundo = UBACKWARD;
  74                 break;
  75         }
  76         return (0);
  77 }