dissertation/usr.bin/talk/display.c

/*	$OpenBSD: display.c,v 1.18 2016/02/01 07:29:25 mestre Exp $	*/
/*	$NetBSD: display.c,v 1.3 1994/12/09 02:14:13 jtc Exp $	*/

/*
 * Copyright (c) 1983, 1993
 *	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. 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.
 */

/*
 * The window 'manager', initializes curses and handles the actual
 * displaying of text
 */
#include <ctype.h>

#include "talk.h"

xwin_t	my_win;
xwin_t	his_win;
WINDOW	*line_win;

int	curses_initialized;
int	high_print;
bool	smooth_scroll;

/*
 * max HAS to be a function, it is called with
 * an argument of the form --foo at least once.
 */
int
max(int a, int b)
{

	return (a > b ? a : b);
}

/*
 * Display some text on somebody's window, processing some control
 * characters while we are at it.
 */
void
display(xwin_t *win, char *text, int size)
{
	int i;
	char cch;

	for (i = 0; i < size; i++) {
		/*
		 * Since we do not use curses's input routines we must
		 * convert '\r' -> '\n' ourselves.
		 */
		if (*text == '\r')
			*text = '\n';
		if (*text == '\n') {
			xscroll(win, 0);
			text++;
			continue;
		}
		/* erase character */
		if (*text == win->cerase) {
			wmove(win->x_win, win->x_line, max(--win->x_col, 0));
			getyx(win->x_win, win->x_line, win->x_col);
			waddch(win->x_win, ' ');
			wmove(win->x_win, win->x_line, win->x_col);
			getyx(win->x_win, win->x_line, win->x_col);
			text++;
			continue;
		}
		/*
		 * On word erase search backwards until we find
		 * the beginning of a word or the beginning of
		 * the line.
		 */
		if (*text == win->werase) {
			int endcol, xcol, i, c;

			endcol = win->x_col;
			xcol = endcol - 1;
			while (xcol >= 0) {
				c = readwin(win->x_win, win->x_line, xcol);
				if (c != ' ')
					break;
				xcol--;
			}
			while (xcol >= 0) {
				c = readwin(win->x_win, win->x_line, xcol);
				if (c == ' ')
					break;
				xcol--;
			}
			wmove(win->x_win, win->x_line, xcol + 1);
			for (i = xcol + 1; i < endcol; i++)
				waddch(win->x_win, ' ');
			wmove(win->x_win, win->x_line, xcol + 1);
			getyx(win->x_win, win->x_line, win->x_col);
			text++;
			continue;
		}
		/* line kill */
		if (*text == win->kill) {
			wmove(win->x_win, win->x_line, 0);
			wclrtoeol(win->x_win);
			getyx(win->x_win, win->x_line, win->x_col);
			text++;
			continue;
		}
		if (*text == '\f') {
			if (win == &my_win)
				wrefresh(curscr);
			text++;
			continue;
		}
		if (win->x_col == COLS-1) {
			/* check for wraparound */
			xscroll(win, 0);
		}
		if (*text != '\t' &&
		    ((!high_print && !isprint((unsigned char)*text)) ||
		      iscntrl((unsigned char)*text))) {
			waddch(win->x_win, '^');
			getyx(win->x_win, win->x_line, win->x_col);
			if (win->x_col == COLS-1) /* check for wraparound */
				xscroll(win, 0);
			cch = (*text & 63) + 64;
			waddch(win->x_win, cch);
		} else
			waddch(win->x_win, (unsigned char)(*text));
		getyx(win->x_win, win->x_line, win->x_col);
		text++;
	}
	wrefresh(win->x_win);
}

/*
 * Read the character at the indicated position in win
 */
int
readwin(WINDOW *win, int line, int col)
{
	int oldline, oldcol;
	int c;

	getyx(win, oldline, oldcol);
	wmove(win, line, col);
	c = winch(win);
	wmove(win, oldline, oldcol);
	return (c);
}

/*
 * Scroll a window, blanking out the line following the current line
 * so that the current position is obvious
 */
void
xscroll(xwin_t *win, int flag)
{

	if (flag == -1) {
		wmove(win->x_win, 0, 0);
		win->x_line = 0;
		win->x_col = 0;
		return;
	}
	win->x_col = 0;
	if (smooth_scroll) {
		if (++win->x_line == win->x_nlines) {
			--win->x_line;
			scroll(win->x_win);
		}
	} else {
		win->x_line = (win->x_line + 1) % win->x_nlines;
		wmove(win->x_win, win->x_line, win->x_col);
		wclrtoeol(win->x_win);
		wmove(win->x_win, (win->x_line + 1) % win->x_nlines,
		    win->x_col);
		wclrtoeol(win->x_win);
	}
	wmove(win->x_win, win->x_line, win->x_col);
}