/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1995-1998 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/* LINTLIBRARY */

/*
 * winsdel.c
 *
 * XCurses Library
 *
 * Copyright 1990, 1995 by Mortice Kern Systems.  All rights reserved.
 *
 */

#ifdef M_RCSID
#ifndef lint
static char rcsID[] =
"$Header: /team/ps/sun_xcurses/archive/local_changes/xcurses/src/lib/"
"libxcurses/src/libc/xcurses/rcs/winsdel.c 1.3 1998/05/27 18:31:31 "
"cbates Exp $";
#endif
#endif

#include <private.h>
#include <stdlib.h>

/*
 * Insert/delete rows from a window.
 *
 * Positive N inserts rows and negative N deletes.  The size of the
 * window remains fixed so that rows insert/deleted will cause rows to
 * disappear/appear at the end of the window.
 *
 * NOTE: This routine called in doupdate.c with curscr as window.
 */
int
winsdelln(WINDOW *w, int n)
{
	int	row;

	/* Check bounds and limit if necessary. */
	if (w->_maxy < w->_cury + abs(n))
		n = (w->_maxy - w->_cury + 1) * (n < 0 ? -1 : 1);

	/* Insert/delete accomplished by pointer shuffling. */
	if (n < 0) {
		/* Delete n lines from current cursor line. */
		(void) __m_ptr_move((void **) w->_line, w->_maxy,
			w->_cury, w->_cury - (n + 1), w->_maxy);

		/* Blank lines come in at the bottom of the screen. */
		row = w->_maxy + n;
	} else {
		/* Insert n lines before current cursor line. */
		(void) __m_ptr_move((void **) w->_line, w->_maxy,
			w->_maxy - n, w->_maxy - 1, w->_cury);

		/* Blank lines inserted at the cursor line. */
		row = w->_cury;
	}

	/* Clear inserted/deleted lines. */
	(void) __m_cc_erase(w, row, 0, row + abs(n) - 1, w->_maxx - 1);

	/* Mark from the cursor line to the end of window as dirty. */
	(void) wtouchln(w, w->_cury, w->_maxy - w->_cury, 1);

	/*
	 * If we insert/delete lines at the top of the screen and we're,
	 * permitted to scroll, then treat the action as a scroll.
	 */
	if (w->_scroll && w->_cury == 0 && n != 0 &&
		(w->_flags & W_FULL_WINDOW) && w->_top == 0 &&
		w->_bottom == w->_maxy)
		w->_scroll += (short) n;
	else
		w->_scroll = 0;

	WSYNC(w);

	return (WFLUSH(w));
}