ex/ex_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: ex_undo.c,v 8.4 1993/12/29 16:12:04 bostic Exp $ (Berkeley) $Date: 1993/12/29 16:12:04 $";
  10 #endif /* not lint */
  11
  12 #include <sys/types.h>
  13
  14 #include "vi.h"
  15 #include "excmd.h"
  16
  17 /*
  18  * ex_undol -- U
  19  *      Undo changes to this line.
  20  */
  21 int
  22 ex_undol(sp, ep, cmdp)
  23         SCR *sp;
  24         EXF *ep;
  25         EXCMDARG *cmdp;
  26 {
  27         if (log_setline(sp, ep))
  28                 return (1);
  29
  30         sp->cno = 0;
  31         return (0);
  32 }
  33
  34 /*
  35  * ex_undo -- u
  36  *      Undo the last change.
  37  */
  38 int
  39 ex_undo(sp, ep, cmdp)
  40         SCR *sp;
  41         EXF *ep;
  42         EXCMDARG *cmdp;
  43 {
  44         MARK m;
  45
  46         /*
  47          * !!!
  48          * Multiple undo isn't available in ex, as there's no '.' command.
  49          * Whether 'u' is undo or redo is toggled each time, unless there
  50          * was a change since the last undo, in which case it's an undo.
  51          */
  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, ep, &m))
  59                         return (1);
  60                 ep->lundo = FORWARD;
  61                 break;
  62         case FORWARD:
  63                 if (log_backward(sp, ep, &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 }