/*-
 * Copyright (c) 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)ex_z.c	8.8 (Berkeley) 8/17/94";
#endif /* not lint */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>

#include <bitstring.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>

#include "compat.h"
#include <db.h>
#include <regex.h>

#include "vi.h"
#include "excmd.h"

/*
 * ex_z -- :[line] z [^-.+=] [count] [flags]
 *
 *	Adjust window.
 */
int
ex_z(sp, ep, cmdp)
	SCR *sp;
	EXF *ep;
	EXCMDARG *cmdp;
{
	MARK abs;
	recno_t cnt, equals, lno;
	int eofcheck;

	/*
	 * !!!
	 * If no count specified, use either two times the size of the
	 * scrolling region, or the size of the window option.  POSIX
	 * 1003.2 claims that the latter is correct, but historic ex/vi
	 * documentation and practice appear to use the scrolling region.
	 * I'm using the window size as it means that the entire screen
	 * is used instead of losing a line to roundoff.  Note, we drop
	 * a line from the cnt if using the window size to leave room for
	 * the next ex prompt.
	 */
	if (F_ISSET(cmdp, E_COUNT))
		cnt = cmdp->count;
	else
#ifdef HISTORIC_PRACTICE
		cnt = O_VAL(sp, O_SCROLL) * 2;
#else
		cnt = O_VAL(sp, O_WINDOW) - 1;
#endif

	equals = 0;
	eofcheck = 0;
	lno = cmdp->addr1.lno;

	switch (F_ISSET(cmdp,
	    E_F_CARAT | E_F_DASH | E_F_DOT | E_F_EQUAL | E_F_PLUS)) {
	case E_F_CARAT:		/* Display cnt * 2 before the line. */
		eofcheck = 1;
		if (lno > cnt * 2)
			cmdp->addr1.lno = (lno - cnt * 2) + 1;
		else
			cmdp->addr1.lno = 1;
		cmdp->addr2.lno = (cmdp->addr1.lno + cnt) - 1;
		break;
	case E_F_DASH:		/* Line goes at the bottom of the screen. */
		cmdp->addr1.lno = lno > cnt ? (lno - cnt) + 1 : 1;
		cmdp->addr2.lno = lno;
		break;
	case E_F_DOT:		/* Line goes in the middle of the screen. */
		/*
		 * !!!
		 * Historically, the "middleness" of the line overrode the
		 * count, so that "3z.19" or "3z.20" would display the first
		 * 12 lines of the file, i.e. (N - 1) / 2 lines before and
		 * after the specified line.
		 */
		eofcheck = 1;
		cnt = (cnt - 1) / 2;
		cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
		cmdp->addr2.lno = lno + cnt;

		/*
		 * !!!
		 * Historically, z. set the absolute cursor mark.
		 */
		abs.lno = sp->lno;
		abs.cno = sp->cno;
		(void)mark_set(sp, ep, ABSMARK1, &abs, 1);
		break;
	case E_F_EQUAL:		/* Center with hyphens. */
		/*
		 * !!!
		 * Strangeness.  The '=' flag is like the '.' flag (see the
		 * above comment, it applies here as well) but with a special
		 * little hack.  Print out lines of hyphens before and after
		 * the specified line.  Additionally, the cursor remains set
		 * on that line.
		 */
		eofcheck = 1;
		cnt = (cnt - 1) / 2;
		cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
		cmdp->addr2.lno = lno - 1;
		if (ex_pr(sp, ep, cmdp))
			return (1);
		(void)ex_printf(EXCOOKIE,
		    "%s", "----------------------------------------\n");
		cmdp->addr2.lno = cmdp->addr1.lno = equals = lno;
		if (ex_pr(sp, ep, cmdp))
			return (1);
		(void)ex_printf(EXCOOKIE,
		    "%s", "----------------------------------------\n");
		cmdp->addr1.lno = lno + 1;
		cmdp->addr2.lno = (lno + cnt) - 1;
		break;
	default:
		/* If no line specified, move to the next one. */
		if (F_ISSET(cmdp, E_ADDRDEF))
			++lno;
		/* FALLTHROUGH */
	case E_F_PLUS:		/* Line goes at the top of the screen. */
		eofcheck = 1;
		cmdp->addr1.lno = lno;
		cmdp->addr2.lno = (lno + cnt) - 1;
		break;
	}

	if (eofcheck) {
		if (file_lline(sp, ep, &lno))
			return (1);
		if (cmdp->addr2.lno > lno)
			cmdp->addr2.lno = lno;
	}

	if (ex_pr(sp, ep, cmdp))
		return (1);
	if (equals)
		sp->lno = equals;
	return (0);
}