diff options
Diffstat (limited to 'contrib/nvi/ex/ex_undo.c')
-rw-r--r-- | contrib/nvi/ex/ex_undo.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/contrib/nvi/ex/ex_undo.c b/contrib/nvi/ex/ex_undo.c new file mode 100644 index 0000000..0b0b5b2 --- /dev/null +++ b/contrib/nvi/ex/ex_undo.c @@ -0,0 +1,77 @@ +/*- + * Copyright (c) 1992, 1993, 1994 + * The Regents of the University of California. All rights reserved. + * Copyright (c) 1992, 1993, 1994, 1995, 1996 + * Keith Bostic. All rights reserved. + * + * See the LICENSE file for redistribution information. + */ + +#include "config.h" + +#ifndef lint +static const char sccsid[] = "@(#)ex_undo.c 10.6 (Berkeley) 3/6/96"; +#endif /* not lint */ + +#include <sys/types.h> +#include <sys/queue.h> + +#include <bitstring.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> + +#include "../common/common.h" + +/* + * ex_undo -- u + * Undo the last change. + * + * PUBLIC: int ex_undo __P((SCR *, EXCMD *)); + */ +int +ex_undo(sp, cmdp) + SCR *sp; + EXCMD *cmdp; +{ + EXF *ep; + MARK m; + + /* + * !!! + * Historic undo always set the previous context mark. + */ + m.lno = sp->lno; + m.cno = sp->cno; + if (mark_set(sp, ABSMARK1, &m, 1)) + return (1); + + /* + * !!! + * Multiple undo isn't available in ex, as there's no '.' command. + * Whether 'u' is undo or redo is toggled each time, unless there + * was a change since the last undo, in which case it's an undo. + */ + ep = sp->ep; + if (!F_ISSET(ep, F_UNDO)) { + F_SET(ep, F_UNDO); + ep->lundo = FORWARD; + } + switch (ep->lundo) { + case BACKWARD: + if (log_forward(sp, &m)) + return (1); + ep->lundo = FORWARD; + break; + case FORWARD: + if (log_backward(sp, &m)) + return (1); + ep->lundo = BACKWARD; + break; + case NOTSET: + abort(); + } + sp->lno = m.lno; + sp->cno = m.cno; + return (0); +} |