inetutils/talk/display.c

/*
  Copyright (C) 1995-2023 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  GNU Inetutils is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see `http://www.gnu.org/licenses/'. */

/*
 * 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 <config.h>

#include <ctype.h>
#include "talk.h"

xwin_t my_win;
xwin_t his_win;
WINDOW *line_win;

int curses_initialized = 0;

#undef max
/*
 * max HAS to be a function, it is called with
 * a argument of the form --foo at least once.
 */
int
max (int a, int b)
{
  return a > b ? a : b;
}

/*
 * Read the character at the indicated position in win
 */
static int
readwin (WINDOW * win, int line, int col)
{
  int oldline, oldcol;
  register 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
 */
static void
xscroll (register 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_line = (win->x_line + 1) % win->x_nlines;
  win->x_col = 0;
  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);
}

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

  for (i = 0; i < size; i++)
    {
      if (*text == '\n')
	{
	  xscroll (win, 0);
	  text++;
	  continue;
	}
      if (*text == '\a')
	{
	  beep ();
	  wrefresh (curscr);
	  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;
	}
      /* Refresh screen with input ^L, Ctrl-L.
       * Local trigger only.
       */
      if (*text == '\f')
	{
	  if (win == &my_win)
	    wrefresh (curscr);
	  text++;
	  continue;
	}
      /* Clear both windows with input ^D, Ctrl-D.
       * Local trigger only.
       */
      if (*text == '\04' && win == &my_win)
	{
	  wclear (my_win.x_win);
	  wclear (his_win.x_win);
	  wrefresh (my_win.x_win);
	  wrefresh (his_win.x_win);
	  text++;
	  continue;
	}
      if (win->x_col == COLS - 1)
	{
	  /* check for wraparound */
	  xscroll (win, 0);
	}

      /*
       * Printable characters, SP, and TAB are printed
       * verbatim.  Characters beyond the ASCII table
       * must be handled.  Beware of sign extension!
       *
       * The locale setting is in effect when testing
       * printability of any input character.
       */
      if (isprint (*text & 0xff) || *text == '\t')
	waddch (win->x_win, *text & 0xff);
      else
	{
	  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);
	}

      getyx (win->x_win, win->x_line, win->x_col);
      text++;
    }
  wrefresh (win->x_win);

  return 0;
}