/*	Copyright (c) 1984 AT&T	*/
/*	  All Rights Reserved  	*/

/*	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T	*/
/*	The copyright notice above does not evidence any   	*/
/*	actual or intended publication of such source code.	*/

#ifndef lint
static	char sccsid[] = "@(#)winsdelln.c 1.1 94/10/31 SMI"; /* from S5R3.1 1.4 */
#endif

#include	"curses_inc.h"

/*
 * Insert/delete lines
 * id < 0 : number of lines to delete
 * id > 0 : number of lines to insert
 */

winsdelln(win, id)
register	WINDOW	*win;
int	id;
{
    register	int	x, y, endy, endx, to, fr, num_lines, dir;
    register	chtype	*sw;
    register	char	*mk;
    int			quick, savimmed, savesync;
    short		*begch, *endch;
#ifdef	_VR3_COMPAT_CODE
    void		(*update_ptr)();

    /*
     * Null out the update pointer so that in wclrtoeol we do not
     * update the _y16 area but we wait till the bottom of this
     * function to do it in one fell swoop.
     */

    if (_y16update)
    {
	update_ptr = _y16update;
	_y16update = NULL;
    }
    else
	update_ptr = NULL;
#endif	/* _VR3_COMPAT_CODE */

    if ((win->_cury >= win->_tmarg) && (win->_cury <= win->_bmarg))
	endy = win->_bmarg + 1;
    else
	endy = win->_maxy;

    if (id < 0)
    {
	/*
	 * Check that the amount of lines to delete aren't larger
	 * than the window.  We save num_lines only so that we don't have
	 * to re-compute if the if comes out true.
	 */

	if ((num_lines = win->_cury - endy) > id)
	    id = num_lines;

	/*
	 * "fr" is the line that we are coming "fr"om and
	 * moving "to" the new place.  This is the offset which
	 * we have to re-align our pointers by.
	 * We want to start setting the current line's pointer
	 * to point to the offset's line.  We want to move line "fr"
	 * to line "to".
	 */

	to = win->_cury;
	fr = to - id;
	num_lines = endy - fr;
	dir = 1;
    }
    else
    {
	/* can't insert more lines than are in the region */
	if ((num_lines = endy - win->_cury) < id)
	    id = num_lines;

	to = endy - 1;
	fr = to - id;
	num_lines = fr - (win->_cury - 1);
	dir = -1;
    }

    /*
     * If this window has no parents or children, then we can manipulate
     * pointers to simulate insert/delete line.  Otherwise,
     * to propogate the changes to parents and siblings
     * we have to memcpy the text around.
     *
     * Set quick to tell us which we have to do.
     */
    quick = ((win->_ndescs <= 0) && (win->_parent == NULL));

    begch = win->_firstch;
    endch = win->_lastch;
    endx = win->_maxx;

    for ( ; num_lines > 0; num_lines--, to += dir, fr += dir)
    {
	/* can be done quickly */
	if (quick)
	{
	    sw = win->_y[to];
	    win->_y[to] = win->_y[fr];
	    win->_y[fr] = sw;
	    if ((win == curscr) && _MARKS != NULL)
	    {
		mk = _MARKS[to];
		_MARKS[to] = _MARKS[fr];
		_MARKS[fr] = mk;
	    }
	}
	else
	    /* slow update */
	    (void) memcpy((char *) win->_y[to], (char *) win->_y[fr], (int) (endx * sizeof(chtype)));


	/*
	 * If this is curscr, the firstch[] and lastch[]
	 * arrays contain blank information.
	 */

	if (win == curscr)
	{
	    begch[to] = begch[fr];
	    endch[to] = endch[fr];
	    _CURHASH[to] = _CURHASH[fr];
	}
	else
	{
	    /* regular window, update the change structure */
	    begch[to] = 0;
	    endch[to] = endx - 1;
	}
    }

    /* clear the insert/delete lines */
    if (id < 0)
	num_lines = endy - to;
    else
	num_lines = to - (win->_cury - 1);

    if (num_lines > 0)		/* Is this if needed ? */
    {
	savimmed = win->_immed;
	savesync = win->_sync;
	win->_immed = win->_sync = FALSE;
	x = win->_curx;
	y = win->_cury;

	win->_curx = 0;
	for (; num_lines > 0; --num_lines, to += dir)
	{
	    win->_cury = to;
	    (void) wclrtoeol(win);
	}

	win->_curx = x;
	win->_cury = y;
	win->_immed = savimmed;
	win->_sync = savesync;
    }
    win->_flags |= (_WINCHANGED|_WINSDEL);

#ifdef	_VR3_COMPAT_CODE
    if (update_ptr)
    {
	_y16update = update_ptr;
	(*_y16update)(win, endy - y, endx, y, 0);
    }
#endif	/* _VR3_COMPAT_CODE */

    if (win->_sync)
	wsyncup(win);

    return ((win != curscr && savimmed) ? wrefresh(win) : OK);
}
