/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)wwinschar.c	3.18 (Berkeley) 08/24/89";
#endif /* not lint */

#include "ww.h"
#include "tt.h"

wwinschar(w, row, col, c, m)
register struct ww *w;
char c, m;
{
	register i;
	int nvis;
	short x = c | m << WWC_MSHIFT;

	/*
	 * First, shift the line.
	 */
	{
		register union ww_char *p, *q;

		p = &w->ww_buf[row][w->ww_b.r];
		q = p - 1;
		for (i = w->ww_b.r - col; --i > 0;)
			*--p = *--q;
		q->c_w = x;
	}

	/*
	 * If can't see it, just return.
	 */
	if (row < w->ww_i.t || row >= w->ww_i.b
	    || w->ww_i.r <= 0 || w->ww_i.r <= col)
		return;

	if (col < w->ww_i.l)
		col = w->ww_i.l;

	/*
	 * Now find out how much is actually changed, and fix wwns.
	 */
	{
		register union ww_char *buf;
		register char *win;
		register union ww_char *ns;
		register char *smap;
		char touched;

		nvis = 0;
		smap = &wwsmap[row][col];
		for (i = col; i < w->ww_i.r && *smap++ != w->ww_index; i++)
			;
		if (i >= w->ww_i.r)
			return;
		col = i;
		buf = w->ww_buf[row];
		win = w->ww_win[row];
		ns = wwns[row];
		smap = &wwsmap[row][i];
		touched = wwtouched[row];
		for (; i < w->ww_i.r; i++) {
			if (*smap++ != w->ww_index)
				continue;
			touched |= WWU_TOUCHED;
			if (win[i])
				ns[i].c_w =
					buf[i].c_w ^ win[i] << WWC_MSHIFT;
			else {
				nvis++;
				ns[i] = buf[i];
			}
		}
		wwtouched[row] = touched;
	}

	/*
	 * Can/Should we use delete character?
	 */
	if ((tt.tt_inschar || tt.tt_insspace) && nvis > (wwncol - col) / 2) {
		register union ww_char *p, *q;

		if (tt.tt_inschar)
			xxinschar(row, col, c, m);
		else {
			xxinsspace(row, col);
			x = ' ';
		}
		p = &wwos[row][wwncol];
		q = p - 1;
		for (i = wwncol - col; --i > 0;)
			*--p = *--q;
		q->c_w = x;
	}
}