77 lines
1.4 KiB
C
77 lines
1.4 KiB
C
/*-
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* Copyright (c) 1992, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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* Copyright (c) 1992, 1993, 1994, 1995, 1996
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* Keith Bostic. All rights reserved.
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*
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* See the LICENSE file for redistribution information.
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*/
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#include "config.h"
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#ifndef lint
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static const char sccsid[] = "$Id: ex_undo.c,v 10.7 2001/06/25 15:19:21 skimo Exp $";
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#endif /* not lint */
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#include <sys/types.h>
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#include <sys/queue.h>
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#include <sys/time.h>
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#include <bitstring.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "../common/common.h"
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/*
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* ex_undo -- u
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* Undo the last change.
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*
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* PUBLIC: int ex_undo(SCR *, EXCMD *);
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*/
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int
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ex_undo(SCR *sp, EXCMD *cmdp)
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{
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EXF *ep;
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MARK m;
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/*
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* !!!
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* Historic undo always set the previous context mark.
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*/
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m.lno = sp->lno;
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m.cno = sp->cno;
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if (mark_set(sp, ABSMARK1, &m, 1))
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return (1);
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/*
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* !!!
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* Multiple undo isn't available in ex, as there's no '.' command.
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* Whether 'u' is undo or redo is toggled each time, unless there
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* was a change since the last undo, in which case it's an undo.
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*/
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ep = sp->ep;
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if (!F_ISSET(ep, F_UNDO)) {
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F_SET(ep, F_UNDO);
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ep->lundo = FORWARD;
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}
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switch (ep->lundo) {
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case BACKWARD:
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if (log_forward(sp, &m))
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return (1);
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ep->lundo = FORWARD;
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break;
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case FORWARD:
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if (log_backward(sp, &m))
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return (1);
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ep->lundo = BACKWARD;
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break;
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case NOTSET:
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abort();
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}
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sp->lno = m.lno;
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sp->cno = m.cno;
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return (0);
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}
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