ncurses-4.2-990116

1 files changed, 1757 insertions, 0 deletions

diff --git a/lib/libcurses/tty/tty_update.c b/lib/libcurses/tty/tty_update.c
new file mode 100644
index 00000000000..9fd81963b5e
--- /dev/null
+++ b/lib/libcurses/tty/tty_update.c
@@ -0,0 +1,1757 @@
+/*	$OpenBSD: tty_update.c,v 1.1 1999/01/18 19:10:27 millert Exp $	*/
+
+/****************************************************************************
+ * Copyright (c) 1998 Free Software Foundation, Inc.                        *
+ *                                                                          *
+ * Permission is hereby granted, free of charge, to any person obtaining a  *
+ * copy of this software and associated documentation files (the            *
+ * "Software"), to deal in the Software without restriction, including      *
+ * without limitation the rights to use, copy, modify, merge, publish,      *
+ * distribute, distribute with modifications, sublicense, and/or sell       *
+ * copies of the Software, and to permit persons to whom the Software is    *
+ * furnished to do so, subject to the following conditions:                 *
+ *                                                                          *
+ * The above copyright notice and this permission notice shall be included  *
+ * in all copies or substantial portions of the Software.                   *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+ * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+ *                                                                          *
+ * Except as contained in this notice, the name(s) of the above copyright   *
+ * holders shall not be used in advertising or otherwise to promote the     *
+ * sale, use or other dealings in this Software without prior written       *
+ * authorization.                                                           *
+ ****************************************************************************/
+
+/****************************************************************************
+ *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
+ *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
+ ****************************************************************************/
+
+
+/*-----------------------------------------------------------------
+ *
+ *	lib_doupdate.c
+ *
+ *	The routine doupdate() and its dependents.  Also _nc_outstr(),
+ *	so all physical output is concentrated here (except _nc_outch()
+ *	in lib_tputs.c).
+ *
+ *-----------------------------------------------------------------*/
+
+#include <curses.priv.h>
+
+#if defined(TRACE) && HAVE_SYS_TIMES_H && HAVE_TIMES
+#define USE_TRACE_TIMES 1
+#else
+#define USE_TRACE_TIMES 0
+#endif
+
+#if HAVE_SYS_TIME_H && HAVE_SYS_TIME_SELECT
+#include <sys/time.h>
+#endif
+
+#if USE_TRACE_TIMES
+#include <sys/times.h>
+#endif
+
+#if USE_FUNC_POLL
+#include <stropts.h>
+#include <poll.h>
+#elif HAVE_SELECT
+#if HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+#endif
+
+#ifdef __BEOS__
+/* BeOS select() only works on sockets.  Use the tty hack instead */
+#include <socket.h>
+#define select check_select
+#endif
+
+#include <term.h>
+
+MODULE_ID("$From: tty_update.c,v 1.109 1998/10/03 19:08:33 tom Exp $")
+
+/*
+ * This define controls the line-breakout optimization.  Every once in a
+ * while during screen refresh, we want to check for input and abort the
+ * update if there's some waiting.  CHECK_INTERVAL controls the number of
+ * changed lines to be emitted between input checks.
+ *
+ * Note: Input-check-and-abort is no longer done if the screen is being
+ * updated from scratch.  This is a feature, not a bug.
+ */
+#define CHECK_INTERVAL	5
+
+/*
+ * Enable checking to see if doupdate and friends are tracking the true
+ * cursor position correctly.  NOTE: this is a debugging hack which will
+ * work ONLY on ANSI-compatible terminals!
+ */
+/* #define POSITION_DEBUG */
+
+static inline chtype ClrBlank ( WINDOW *win );
+static int ClrBottom(int total);
+static int InsStr( chtype *line, int count );
+static void ClearScreen( chtype blank );
+static void ClrUpdate( WINDOW *win );
+static void DelChar( int count );
+static void TransformLine( int const lineno );
+
+#ifdef POSITION_DEBUG
+/****************************************************************************
+ *
+ * Debugging code.  Only works on ANSI-standard terminals.
+ *
+ ****************************************************************************/
+
+void position_check(int expected_y, int expected_x, char *legend)
+/* check to see if the real cursor position matches the virtual */
+{
+    static char  buf[9];
+    int y, x;
+
+    if (_nc_tracing)
+	return;
+
+    memset(buf, '\0', sizeof(buf));
+    (void) write(1, "\033[6n", 4);	/* only works on ANSI-compatibles */
+    (void) read(0, (void *)buf, 8);
+    _tracef("probe returned %s", _nc_visbuf(buf));
+
+    /* try to interpret as a position report */
+    if (sscanf(buf, "\033[%d;%dR", &y, &x) != 2)
+	_tracef("position probe failed in %s", legend);
+    else if (y - 1 != expected_y || x - 1 != expected_x)
+	_tracef("position seen (%d, %d) doesn't match expected one (%d, %d) in %s",
+		y-1, x-1, expected_y, expected_x, legend);
+    else
+	_tracef("position matches OK in %s", legend);
+}
+#endif /* POSITION_DEBUG */
+
+/****************************************************************************
+ *
+ * Optimized update code
+ *
+ ****************************************************************************/
+
+static inline void GoTo(int const row, int const col)
+{
+	chtype	oldattr = SP->_current_attr;
+
+	TR(TRACE_MOVE, ("GoTo(%d, %d) from (%d, %d)",
+			row, col, SP->_cursrow, SP->_curscol));
+
+#ifdef POSITION_DEBUG
+	position_check(SP->_cursrow, SP->_curscol, "GoTo");
+#endif /* POSITION_DEBUG */
+
+	/*
+	 * Force restore even if msgr is on when we're in an alternate
+	 * character set -- these have a strong tendency to screw up the
+	 * CR & LF used for local character motions!
+	 */
+	if ((oldattr & A_ALTCHARSET)
+	    || (oldattr && !move_standout_mode))
+	{
+		TR(TRACE_CHARPUT, ("turning off (%#lx) %s before move",
+		   oldattr, _traceattr(oldattr)));
+		vidattr(A_NORMAL);
+	}
+
+	mvcur(SP->_cursrow, SP->_curscol, row, col);
+	SP->_cursrow = row;
+	SP->_curscol = col;
+}
+
+static inline void PutAttrChar(chtype ch)
+{
+	if (tilde_glitch && (TextOf(ch) == '~'))
+		ch = ('`' | AttrOf(ch));
+
+	TR(TRACE_CHARPUT, ("PutAttrChar(%s) at (%d, %d)",
+			  _tracechtype(ch),
+			   SP->_cursrow, SP->_curscol));
+	UpdateAttrs(ch);
+	putc((int)TextOf(ch), SP->_ofp);
+#ifdef TRACE
+	_nc_outchars++;
+#endif /* TRACE */
+	SP->_curscol++;
+	if (char_padding) {
+		TPUTS_TRACE("char_padding");
+		putp(char_padding);
+	}
+}
+
+static bool check_pending(void)
+/* check for pending input */
+{
+	bool have_pending = FALSE;
+
+	/*
+	 * Only carry out this check when the flag is zero, otherwise we'll
+	 * have the refreshing slow down drastically (or stop) if there's an
+	 * unread character available.
+	 */
+	if(SP->_fifohold != 0)
+		return FALSE;
+
+	if (SP->_checkfd >= 0) {
+#if USE_FUNC_POLL
+		struct pollfd fds[1];
+		fds[0].fd = SP->_checkfd;
+		fds[0].events = POLLIN;
+		if (poll(fds, 1, 0) > 0)
+		{
+			have_pending = TRUE;
+		}
+#elif HAVE_SELECT
+		fd_set fdset;
+		struct timeval ktimeout;
+
+		ktimeout.tv_sec =
+		ktimeout.tv_usec = 0;
+
+		FD_ZERO(&fdset);
+		FD_SET(SP->_checkfd, &fdset);
+		if (select(SP->_checkfd+1, &fdset, NULL, NULL, &ktimeout) != 0)
+		{
+			have_pending = TRUE;
+		}
+#endif
+	}
+	if (have_pending) {
+		SP->_fifohold = 5;
+		fflush(SP->_ofp);
+	}
+	return FALSE;
+}
+
+/*
+ * No one supports recursive inline functions.  However, gcc is quieter if we
+ * instantiate the recursive part separately.
+ */
+#if CC_HAS_INLINE_FUNCS
+static void callPutChar(chtype const);
+#else
+#define callPutChar(ch) PutChar(ch)
+#endif
+
+static inline void PutChar(chtype const ch);	/* forward declaration */
+
+/* put char at lower right corner */
+static void PutCharLR(chtype const ch)
+{
+    if (!auto_right_margin)
+    {
+	/* we can put the char directly */
+	PutAttrChar(ch);
+    }
+    else if (enter_am_mode && exit_am_mode)
+    {
+	/* we can suppress automargin */
+	TPUTS_TRACE("exit_am_mode");
+	putp(exit_am_mode);
+
+	PutAttrChar(ch);
+
+	TPUTS_TRACE("enter_am_mode");
+	putp(enter_am_mode);
+    }
+    else if ((enter_insert_mode && exit_insert_mode)
+	     || insert_character || parm_ich)
+    {
+	GoTo(screen_lines-1,screen_columns-2);
+	callPutChar(ch);
+	GoTo(screen_lines-1,screen_columns-2);
+	InsStr(newscr->_line[screen_lines-1].text+screen_columns-2,1);
+    }
+}
+
+static void wrap_cursor(void)
+{
+    if (eat_newline_glitch)
+    {
+	/*
+	 * xenl can manifest two different ways.  The vt100
+	 * way is that, when you'd expect the cursor to wrap,
+	 * it stays hung at the right margin (on top of the
+	 * character just emitted) and doesn't wrap until the
+	 * *next* graphic char is emitted.  The c100 way is
+	 * to ignore LF received just after an am wrap.
+	 *
+	 * An aggressive way to handle this would be to
+	 * emit CR/LF after the char and then assume the wrap
+	 * is done, you're on the first position of the next
+	 * line, and the terminal out of its weird state.
+	 * Here it's safe to just tell the code that the
+	 * cursor is in hyperspace and let the next mvcur()
+	 * call straighten things out.
+	 */
+	SP->_curscol = -1;
+	SP->_cursrow = -1;
+    }
+    else if (auto_right_margin)
+    {
+	SP->_curscol = 0;
+	SP->_cursrow++;
+    }
+    else
+    {
+	SP->_curscol--;
+    }
+}
+
+static inline void PutChar(chtype const ch)
+/* insert character, handling automargin stuff */
+{
+    if (SP->_cursrow == screen_lines-1 && SP->_curscol == screen_columns-1)
+	PutCharLR(ch);
+    else
+	PutAttrChar(ch);
+
+    if (SP->_curscol >= screen_columns)
+	wrap_cursor();
+
+#ifdef POSITION_DEBUG
+    position_check(SP->_cursrow, SP->_curscol, "PutChar");
+#endif /* POSITION_DEBUG */
+}
+
+/*
+ * Issue a given span of characters from an array.
+ * Must be functionally equivalent to:
+ *	for (i = 0; i < num; i++)
+ *	    PutChar(ntext[i]);
+ * but can leave the cursor positioned at the middle of the interval.
+ *
+ * Returns: 0 - cursor is at the end of interval
+ *	    1 - cursor is somewhere in the middle
+ *
+ * This code is optimized using ech and rep.
+ */
+static int EmitRange(const chtype *ntext, int num)
+{
+    int	i;
+
+    if (erase_chars || repeat_char)
+    {
+	while (num > 0)
+	{
+	    int	runcount;
+	    chtype ntext0;
+
+	    while (num>1 && ntext[0]!=ntext[1])
+	    {
+		PutChar(ntext[0]);
+		ntext++;
+		num--;
+	    }
+	    ntext0 = ntext[0];
+	    if (num==1)
+	    {
+		PutChar(ntext0);
+		return 0;
+	    }
+	    runcount = 2;
+
+	    while (runcount < num && ntext[runcount] == ntext0)
+		runcount++;
+
+	    /*
+	     * The cost expression in the middle isn't exactly right.
+	     * _cup_cost is an upper bound on the cost for moving to the
+	     * end of the erased area, but not the cost itself (which we
+	     * can't compute without emitting the move).  This may result
+	     * in erase_chars not getting used in some situations for
+	     * which it would be marginally advantageous.
+	     */
+	    if (erase_chars
+		&& runcount > SP->_ech_cost + SP->_cup_cost
+		&& can_clear_with(ntext0))
+	    {
+		UpdateAttrs(ntext0);
+		putp(tparm(erase_chars, runcount));
+
+		/*
+		 * If this is the last part of the given interval,
+		 * don't bother moving cursor, since it can be the
+		 * last update on the line.
+		 */
+		if (runcount < num)
+		    GoTo(SP->_cursrow, SP->_curscol + runcount);
+		else
+		    return 1;	/* cursor stays in the middle */
+	    }
+	    else if (repeat_char && runcount > SP->_rep_cost)
+	    {
+		bool wrap_possible = (SP->_curscol + runcount >= screen_columns);
+		int rep_count = runcount;
+
+		if (wrap_possible)
+		    rep_count--;
+
+		UpdateAttrs(ntext0);
+		putp(tparm(repeat_char, TextOf(ntext0), rep_count));
+		SP->_curscol += rep_count;
+
+		if (wrap_possible)
+		    PutChar(ntext0);
+	    }
+	    else
+	    {
+		for (i = 0; i < runcount; i++)
+		    PutChar(ntext[i]);
+	    }
+	    ntext += runcount;
+	    num -= runcount;
+	}
+	return 0;
+    }
+
+    for (i = 0; i < num; i++)
+	PutChar(ntext[i]);
+    return 0;
+}
+
+/*
+ * Output the line in the given range [first .. last]
+ *
+ * If there's a run of identical characters that's long enough to justify
+ * cursor movement, use that also.
+ *
+ * Returns: same as EmitRange
+ */
+static int PutRange(
+	const chtype *otext,
+	const chtype *ntext,
+	int row,
+	int first, int last)
+{
+	int j, run;
+	int cost = min(SP->_cup_ch_cost, SP->_hpa_ch_cost);
+
+	TR(TRACE_CHARPUT, ("PutRange(%p, %p, %d, %d, %d)",
+			 otext, ntext, row, first, last));
+
+	if (otext != ntext
+	 && (last-first+1) > cost) {
+		for (j = first, run = 0; j <= last; j++) {
+			if (otext[j] == ntext[j]) {
+				run++;
+			} else {
+				if (run > cost) {
+					int before_run = (j - run);
+					EmitRange(ntext+first, before_run-first);
+					GoTo(row, first = j);
+				}
+				run = 0;
+			}
+		}
+	}
+	return EmitRange(ntext + first, last-first+1);
+}
+
+#if CC_HAS_INLINE_FUNCS
+static void callPutChar(chtype const ch)
+{
+	PutChar(ch);
+}
+#endif
+
+#define MARK_NOCHANGE(win,row) \
+	{ \
+		win->_line[row].firstchar = _NOCHANGE; \
+		win->_line[row].lastchar = _NOCHANGE; \
+		if_USE_SCROLL_HINTS(win->_line[row].oldindex = row); \
+	}
+
+int doupdate(void)
+{
+int	i;
+int	nonempty;
+#if USE_TRACE_TIMES
+struct tms before, after;
+#endif /* USE_TRACE_TIMES */
+
+	T((T_CALLED("doupdate()")));
+
+#ifdef TRACE
+	if (_nc_tracing & TRACE_UPDATE)
+	{
+	    if (curscr->_clear)
+		_tracef("curscr is clear");
+	    else
+		_tracedump("curscr", curscr);
+	    _tracedump("newscr", newscr);
+	}
+#endif /* TRACE */
+
+	_nc_signal_handler(FALSE);
+
+	if (SP->_fifohold)
+		SP->_fifohold--;
+
+#if USE_SIZECHANGE
+	if (SP->_endwin || SP->_sig_winch)
+	{
+		/*
+		 * This is a transparent extension:  XSI does not address it,
+		 * and applications need not know that ncurses can do it.
+		 *
+		 * Check if the terminal size has changed while curses was off
+		 * (this can happen in an xterm, for example), and resize the
+		 * ncurses data structures accordingly.
+		 */
+		_nc_update_screensize();
+	}
+#endif
+
+	if (SP->_endwin) {
+
+		T(("coming back from shell mode"));
+		reset_prog_mode();
+
+		_nc_mvcur_resume();
+		_nc_screen_resume();
+		SP->_mouse_resume(SP);
+
+		SP->_endwin = FALSE;
+	}
+
+#if USE_TRACE_TIMES
+	/* zero the metering machinery */
+	_nc_outchars = 0;
+	(void) times(&before);
+#endif /* USE_TRACE_TIMES */
+
+	/*
+	 * This is the support for magic-cookie terminals.  The
+	 * theory: we scan the virtual screen looking for attribute
+	 * turnons.  Where we find one, check to make sure it's
+	 * realizable by seeing if the required number of
+	 * un-attributed blanks are present before and after the
+	 * attributed range; try to shift the range boundaries over
+	 * blanks (not changing the screen display) so this becomes
+	 * true.  If it is, shift the beginning attribute change
+	 * appropriately (the end one, if we've gotten this far, is
+	 * guaranteed room for its cookie). If not, nuke the added
+	 * attributes out of the span.
+	 */
+#if USE_XMC_SUPPORT
+	if (magic_cookie_glitch > 0) {
+	    int	j, k;
+	    attr_t rattr = A_NORMAL;
+
+	    for (i = 0; i < screen_lines; i++)
+		for (j = 0; j < screen_columns; j++)
+		{
+		    bool failed = FALSE;
+		    chtype turnon = AttrOf(newscr->_line[i].text[j]) & ~rattr;
+
+		    /* is an attribute turned on here? */
+		    if (turnon == 0) {
+			rattr = AttrOf(newscr->_line[i].text[j]);
+			continue;
+		    }
+
+		    T(("At (%d, %d): from %s...", i, j, _traceattr(rattr)));
+		    T(("...to %s",_traceattr(turnon)));
+
+		    /*
+		     * If the attribute change location is a blank with a
+		     * "safe" attribute, undo the attribute turnon.  This may
+		     * ensure there's enough room to set the attribute before
+		     * the first non-blank in the run.
+		     */
+#define SAFE(a)	!((a) & (chtype)~NONBLANK_ATTR)
+		    if (TextOf(newscr->_line[i].text[j])==' ' && SAFE(turnon))
+		    {
+			newscr->_line[i].text[j] &= ~turnon;
+			continue;
+		    }
+
+		    /* check that there's enough room at start of span */
+		    for (k = 1; k <= magic_cookie_glitch; k++)
+			if (j-k < 0
+				|| TextOf(newscr->_line[i].text[j-k]) != ' '
+				|| !SAFE(AttrOf(newscr->_line[i].text[j-k])))
+			    failed = TRUE;
+		    if (!failed)
+		    {
+			bool	end_onscreen = FALSE;
+			int	m, n = j;
+
+			/* find end of span, if it's onscreen */
+			for (m = i; m < screen_lines; m++)
+			{
+			    for ( ; n < screen_columns; n++)
+			    {
+				if (AttrOf(newscr->_line[m].text[n]) == rattr)
+				{
+				    end_onscreen = TRUE;
+				    T(("Range attributed with %s ends at (%d, %d)",
+				       _traceattr(turnon),m,n));
+				    goto foundit;
+				}
+			    }
+			    n = 0;
+			}
+			T(("Range attributed with %s ends offscreen",
+			    _traceattr(turnon)));
+		    foundit:;
+
+			if (end_onscreen)
+			{
+			    chtype	*lastline = newscr->_line[m].text;
+
+			    /*
+			     * If there are safely-attributed blanks at the
+			     * end of the range, shorten the range.  This will
+			     * help ensure that there is enough room at end
+			     * of span.
+			     */
+			    while (n >= 0
+				   && TextOf(lastline[n]) == ' '
+				   && SAFE(AttrOf(lastline[n])))
+				lastline[n--] &= ~turnon;
+
+			    /* check that there's enough room at end of span */
+			    for (k = 1; k <= magic_cookie_glitch; k++)
+				if (n + k >= screen_columns
+					|| TextOf(lastline[n + k]) != ' '
+					|| !SAFE(AttrOf(lastline[n+k])))
+				    failed = TRUE;
+			}
+		    }
+
+		    if (failed)
+		    {
+			int p, q = j;
+
+			T(("Clearing %s beginning at (%d, %d)",
+						_traceattr(turnon), i, j));
+
+			/* turn off new attributes over span */
+			for (p = i; p < screen_lines; p++)
+			{
+			    for ( ; q < screen_columns; q++)
+			    {
+				if (AttrOf(newscr->_line[p].text[q]) == rattr)
+				    goto foundend;
+				newscr->_line[p].text[q] &= ~turnon;
+			    }
+			    q = 0;
+			}
+		    foundend:;
+		    }
+		    else
+		    {
+			T(("Cookie space for %s found before (%d, %d)",
+						_traceattr(turnon), i, j));
+
+			/*
+			 * back up the start of range so there's room
+			 * for cookies before the first nonblank character
+			 */
+			for (k = 1; k <= magic_cookie_glitch; k++)
+			    newscr->_line[i].text[j-k] |= turnon;
+		    }
+
+		    rattr = AttrOf(newscr->_line[i].text[j]);
+		}
+
+#ifdef TRACE
+	    /* show altered highlights after magic-cookie check */
+	    if (_nc_tracing & TRACE_UPDATE)
+	    {
+		_tracef("After magic-cookie check...");
+		_tracedump("newscr", newscr);
+	    }
+#endif /* TRACE */
+	}
+#endif	/* USE_XMC_SUPPORT */
+
+	nonempty = 0;
+	if (curscr->_clear) {		/* force refresh ? */
+		/* yes, clear all & update */
+		T(("clearing and updating curscr"));
+		if (is_wintouched(newscr))
+			ClrUpdate(newscr);
+		else
+			ClrUpdate(curscr);
+		curscr->_clear = FALSE;	/* reset flag */
+		newscr->_clear = FALSE;	/* reset flag */
+	} else if (newscr->_clear) {
+		T(("clearing and updating newscr"));
+		ClrUpdate(newscr);
+		newscr->_clear = FALSE;
+	} else {
+		int changedlines = CHECK_INTERVAL;
+
+		if(check_pending())
+		    goto cleanup;
+
+		nonempty = min(screen_lines, newscr->_maxy+1);
+
+		if (SP->_scrolling) {
+			_nc_scroll_optimize();
+		}
+
+		nonempty = ClrBottom(nonempty);
+
+		T(("Transforming lines, nonempty %d", nonempty));
+		for (i = 0; i < nonempty; i++) {
+			/*
+			 * Here is our line-breakout optimization.
+			 */
+			if (changedlines == CHECK_INTERVAL)
+			{
+			    if (check_pending())
+				goto cleanup;
+			    changedlines = 0;
+			}
+
+			/*
+			 * newscr->line[i].firstchar is normally set
+			 * by wnoutrefresh.  curscr->line[i].firstchar
+			 * is normally set by _nc_scroll_window in the
+			 * vertical-movement optimization code,
+			 */
+			if (newscr->_line[i].firstchar != _NOCHANGE
+			 || curscr->_line[i].firstchar != _NOCHANGE)
+			{
+				TransformLine(i);
+				changedlines++;
+			}
+
+			/* mark line changed successfully */
+			if (i <= newscr->_maxy)
+				MARK_NOCHANGE(newscr,i)
+			if (i <= curscr->_maxy)
+				MARK_NOCHANGE(curscr,i)
+		}
+	}
+
+	/* put everything back in sync */
+	for (i = nonempty; i <= newscr->_maxy; i++)
+		MARK_NOCHANGE(newscr,i)
+	for (i = nonempty; i <= curscr->_maxy; i++)
+		MARK_NOCHANGE(curscr,i)
+
+	if (!newscr->_leaveok)
+	{
+		curscr->_curx = newscr->_curx;
+		curscr->_cury = newscr->_cury;
+
+		GoTo(curscr->_cury, curscr->_curx);
+	}
+
+    cleanup:
+	/*
+	 * Keep the physical screen in normal mode in case we get other
+	 * processes writing to the screen.
+	 */
+	UpdateAttrs(A_NORMAL);
+
+	fflush(SP->_ofp);
+	curscr->_attrs = newscr->_attrs;
+/*	curscr->_bkgd  = newscr->_bkgd; */
+
+#if USE_TRACE_TIMES
+	(void) times(&after);
+	TR(TRACE_TIMES, ("Update cost: %ld chars, %ld clocks system time, %ld clocks user time",
+	    _nc_outchars,
+	    after.tms_stime-before.tms_stime,
+	    after.tms_utime-before.tms_utime));
+#endif /* USE_TRACE_TIMES */
+
+	_nc_signal_handler(TRUE);
+
+	returnCode(OK);
+}
+
+/*
+ *	ClrBlank(win)
+ *
+ *	Returns the attributed character that corresponds to the "cleared"
+ *	screen.  If the terminal has the back-color-erase feature, this will be
+ *	colored according to the wbkgd() call.
+ *
+ *	We treat 'curscr' specially because it isn't supposed to be set directly
+ *	in the wbkgd() call.  Assume 'stdscr' for this case.
+ */
+#define BCE_ATTRS (A_NORMAL|A_COLOR)
+#define BCE_BKGD(win) (((win) == curscr ? stdscr : (win))->_bkgd)
+
+static inline chtype ClrBlank (WINDOW *win)
+{
+chtype	blank = BLANK;
+	if (back_color_erase)
+		blank |= (BCE_BKGD(win) & BCE_ATTRS);
+	return blank;
+}
+
+/*
+**	ClrUpdate(win)
+**
+**	Update by clearing and redrawing the entire screen.
+**
+*/
+
+static void ClrUpdate(WINDOW *win)
+{
+	int i;
+	chtype blank = ClrBlank(win);
+	int nonempty = min(screen_lines, newscr->_maxy+1);
+
+	T(("ClrUpdate() called"));
+
+	if (win == curscr) {
+		/* discard updates */
+		for (i = 0; i < screen_lines ; i++) {
+			memcpy( newscr->_line[i].text,
+				curscr->_line[i].text,
+				screen_columns * sizeof(chtype));
+		}
+	}
+
+	ClearScreen(blank);
+
+	T(("updating screen from scratch"));
+
+	nonempty = ClrBottom(nonempty);
+
+	for (i = 0; i < nonempty; i++)
+		TransformLine(i);
+}
+
+/*
+**	ClrToEOL(blank)
+**
+**	Clear to end of current line, starting at the cursor position
+*/
+
+static void ClrToEOL(chtype blank)
+{
+int	j;
+bool	needclear = FALSE;
+
+	for (j = SP->_curscol; j < screen_columns; j++)
+	{
+	    chtype *cp = &(curscr->_line[SP->_cursrow].text[j]);
+
+	    if (*cp != blank)
+	    {
+		*cp = blank;
+		needclear = TRUE;
+	    }
+	}
+
+	if (needclear)
+	{
+	    UpdateAttrs(blank);
+	    TPUTS_TRACE("clr_eol");
+	    if (SP->_el_cost > (screen_columns - SP->_curscol))
+	    {
+		int count = (screen_columns - SP->_curscol);
+		while (count-- > 0)
+			PutChar(blank);
+	    }
+	    else
+		putp(clr_eol);
+	}
+}
+
+/*
+**	ClrToEOS(blank)
+**
+**	Clear to end of screen, starting at the cursor position
+*/
+
+static void ClrToEOS(chtype blank)
+{
+int row, col;
+
+	UpdateAttrs(blank);
+	TPUTS_TRACE("clr_eos");
+	row = SP->_cursrow;
+	tputs(clr_eos, screen_lines-row, _nc_outch);
+
+	for (col = SP->_curscol; col < screen_columns; col++)
+		curscr->_line[row].text[col] = blank;
+
+	for (row++; row < screen_lines; row++)
+	{
+		for (col = 0; col < screen_columns; col++)
+			curscr->_line[row].text[col] = blank;
+	}
+}
+
+/*
+ *	ClrBottom(total)
+ *
+ *	Test if clearing the end of the screen would satisfy part of the
+ *	screen-update.  Do this by scanning backwards through the lines in the
+ *	screen, checking if each is blank, and one or more are changed.
+ */
+static int ClrBottom(int total)
+{
+static	chtype	*tstLine;
+static	size_t	lenLine;
+
+int	row, col;
+int	top    = total;
+int	last   = min(screen_columns, newscr->_maxx+1);
+size_t	length = sizeof(chtype) * last;
+chtype	blank  = newscr->_line[total-1].text[last-1]; /* lower right char */
+
+	if(!clr_eos || !can_clear_with(blank))
+		return total;
+
+	if (tstLine == 0 || length > lenLine) {
+		tstLine = (chtype *)_nc_doalloc(tstLine, length);
+	}
+
+	if (tstLine != 0) {
+		lenLine = length;
+		for (col = 0; col < last; col++)
+			tstLine[col] = blank;
+
+		for (row = total-1; row >= 0; row--) {
+			if (memcmp(tstLine, newscr->_line[row].text, length))
+				break;
+			if (memcmp(tstLine, curscr->_line[row].text, length))
+				top = row;
+		}
+
+		/* don't use clr_eos for just one line if clr_eol available */
+		if (top < total-1 || (top < total && !clr_eol && !clr_bol)) {
+			GoTo(top,0);
+			ClrToEOS(blank);
+			total = top;
+			if (SP->oldhash && SP->newhash)
+			{
+				for (row = top; row < screen_lines; row++)
+					SP->oldhash[row] = SP->newhash[row];
+			}
+		}
+	}
+#if NO_LEAKS
+	if (tstLine != 0)
+		FreeAndNull(tstLine);
+#endif
+	return total;
+}
+
+
+/*
+**	TransformLine(lineno)
+**
+**	Transform the given line in curscr to the one in newscr, using
+**	Insert/Delete Character if _nc_idcok && has_ic().
+**
+**		firstChar = position of first different character in line
+**		oLastChar = position of last different character in old line
+**		nLastChar = position of last different character in new line
+**
+**		move to firstChar
+**		overwrite chars up to min(oLastChar, nLastChar)
+**		if oLastChar < nLastChar
+**			insert newLine[oLastChar+1..nLastChar]
+**		else
+**			delete oLastChar - nLastChar spaces
+*/
+
+static void TransformLine(int const lineno)
+{
+int	firstChar, oLastChar, nLastChar;
+chtype	*newLine = newscr->_line[lineno].text;
+chtype	*oldLine = curscr->_line[lineno].text;
+int	n;
+bool	attrchanged = FALSE;
+
+	T(("TransformLine(%d) called", lineno));
+
+	/* copy new hash value to old one */
+	if (SP->oldhash && SP->newhash)
+		SP->oldhash[lineno] = SP->newhash[lineno];
+
+	if(ceol_standout_glitch && clr_eol) {
+		firstChar = 0;
+		while(firstChar < screen_columns) {
+			if(AttrOf(newLine[firstChar]) != AttrOf(oldLine[firstChar]))
+				attrchanged = TRUE;
+			firstChar++;
+		}
+	}
+
+	firstChar = 0;
+
+	if (attrchanged) {	/* we may have to disregard the whole line */
+		GoTo(lineno, firstChar);
+		ClrToEOL(ClrBlank(curscr));
+		PutRange(oldLine, newLine, lineno, 0, (screen_columns-1));
+#if USE_XMC_SUPPORT
+
+#define NEW(r,c) newscr->_line[r].text[c]
+#define xmc_turn_on(a,b) ((((a)^(b)) & ~(a) & SP->_xmc_triggers) != 0)
+#define xmc_turn_off(a,b) xmc_turn_on(b,a)
+
+	/*
+	 * This is a very simple loop to paint characters which may have the
+	 * magic cookie glitch embedded.  It doesn't know much about video
+	 * attributes which are continued from one line to the next.  It
+	 * assumes that we have filtered out requests for attribute changes
+	 * that do not get mapped to blank positions.
+	 *
+	 * FIXME: we are not keeping track of where we put the cookies, so this
+	 * will work properly only once, since we may overwrite a cookie in a
+	 * following operation.
+	 */
+	} else if (magic_cookie_glitch > 0) {
+		GoTo(lineno, firstChar);
+		for (n = 0; n < screen_columns; n++) {
+			int m = n + magic_cookie_glitch;
+
+			/* check for turn-on:
+			 * If we are writing an attributed blank, where the
+			 * previous cell is not attributed.
+			 */
+			if (TextOf(newLine[n]) == ' '
+			 && ((n > 0
+			   && xmc_turn_on(newLine[n-1], newLine[n]))
+			  || (n == 0
+			   && lineno > 0
+			   && xmc_turn_on(NEW(lineno-1,screen_columns-1), newLine[n])))) {
+				n = m;
+			}
+
+			PutChar(newLine[n]);
+
+			/* check for turn-off:
+			 * If we are writing an attributed non-blank, where the
+			 * next cell is blank, and not attributed.
+			 */
+			if (TextOf(newLine[n]) != ' '
+			 && ((n+1 < screen_columns
+			   && xmc_turn_off(newLine[n], newLine[n+1]))
+			  || (n+1 >= screen_columns
+			   && lineno+1 < screen_lines
+			   && xmc_turn_off(newLine[n], NEW(lineno+1,0))))) {
+				n = m;
+			}
+
+		}
+#undef NEW
+#endif
+	} else {
+		chtype blank;
+
+		/* find the first differing character */
+		while (firstChar < screen_columns  &&
+				newLine[firstChar] == oldLine[firstChar])
+			firstChar++;
+
+		/* if there wasn't one, we're done */
+		if (firstChar >= screen_columns)
+			return;
+
+		/* it may be cheap to clear leading whitespace with clr_bol */
+		if (clr_bol && can_clear_with(blank=newLine[0]))
+		{
+			int oFirstChar, nFirstChar;
+
+			for (oFirstChar = 0; oFirstChar < screen_columns; oFirstChar++)
+				if (oldLine[oFirstChar] != blank)
+					break;
+			for (nFirstChar = 0; nFirstChar < screen_columns; nFirstChar++)
+				if (newLine[nFirstChar] != blank)
+					break;
+
+			if (nFirstChar > oFirstChar + SP->_el1_cost)
+			{
+			    if (nFirstChar >= screen_columns && SP->_el_cost <= SP->_el1_cost)
+			    {
+				GoTo(lineno, 0);
+				UpdateAttrs(blank);
+				TPUTS_TRACE("clr_eol");
+				putp(clr_eol);
+			    }
+			    else
+			    {
+				GoTo(lineno, nFirstChar - 1);
+				UpdateAttrs(blank);
+				TPUTS_TRACE("clr_bol");
+				putp(clr_bol);
+			    }
+
+			    while (firstChar < nFirstChar)
+				oldLine[firstChar++] = blank;
+
+			    if (firstChar >= screen_columns)
+				return;
+			}
+		}
+
+		blank = newLine[screen_columns-1];
+
+		if(!can_clear_with(blank))
+		{
+			/* find the last differing character */
+			nLastChar = screen_columns - 1;
+
+			while (nLastChar > firstChar
+			 && newLine[nLastChar] == oldLine[nLastChar])
+				nLastChar--;
+
+			if (nLastChar >= firstChar) {
+				GoTo(lineno, firstChar);
+				PutRange(oldLine, newLine, lineno, firstChar, nLastChar);
+				memcpy( oldLine + firstChar,
+					newLine + firstChar,
+					(nLastChar - firstChar + 1) * sizeof(chtype));
+			}
+			return;
+		}
+
+		/* find last non-blank character on old line */
+		oLastChar = screen_columns - 1;
+		while (oLastChar > firstChar  &&  oldLine[oLastChar] == blank)
+			oLastChar--;
+
+		/* find last non-blank character on new line */
+		nLastChar = screen_columns - 1;
+		while (nLastChar > firstChar  &&  newLine[nLastChar] == blank)
+			nLastChar--;
+
+		if((nLastChar == firstChar)
+		 && (SP->_el_cost < (oLastChar - nLastChar))) {
+			GoTo(lineno, firstChar);
+			if(newLine[firstChar] != blank )
+				PutChar(newLine[firstChar]);
+			ClrToEOL(blank);
+		} else if( (nLastChar != oLastChar)
+			&& (newLine[nLastChar] != oldLine[oLastChar]
+				|| !(_nc_idcok && has_ic())) ) {
+			GoTo(lineno, firstChar);
+			if ((oLastChar - nLastChar) > SP->_el_cost) {
+				if(PutRange(oldLine, newLine, lineno, firstChar, nLastChar))
+				    GoTo(lineno, nLastChar+1);
+				ClrToEOL(blank);
+			} else {
+				n = max( nLastChar , oLastChar );
+				PutRange(oldLine, newLine, lineno, firstChar, n);
+			}
+		} else {
+			int nLastNonblank = nLastChar;
+			int oLastNonblank = oLastChar;
+
+			/* find the last characters that really differ */
+			while (newLine[nLastChar] == oldLine[oLastChar]) {
+				if (nLastChar != 0
+				 && oLastChar != 0) {
+					nLastChar--;
+					oLastChar--;
+				 } else {
+					break;
+				 }
+			}
+
+			n = min(oLastChar, nLastChar);
+			if (n >= firstChar) {
+				GoTo(lineno, firstChar);
+				PutRange(oldLine, newLine, lineno, firstChar, n);
+			}
+
+			if (oLastChar < nLastChar) {
+				int m = max(nLastNonblank, oLastNonblank);
+				GoTo(lineno, n+1);
+				if (InsCharCost(nLastChar - oLastChar)
+				 > (m - n)) {
+					PutRange(oldLine, newLine, lineno, n+1, m);
+				} else {
+					InsStr(&newLine[n+1], nLastChar - oLastChar);
+				}
+			} else if (oLastChar > nLastChar ) {
+				GoTo(lineno, n+1);
+				if (DelCharCost(oLastChar - nLastChar)
+				    > SP->_el_cost + nLastNonblank - (n+1)) {
+					if(PutRange(oldLine, newLine, lineno,
+							n+1, nLastNonblank))
+						GoTo(lineno, nLastNonblank+1);
+					ClrToEOL(blank);
+				} else {
+					/*
+					 * The delete-char sequence will
+					 * effectively shift in blanks from the
+					 * right margin of the screen.  Ensure
+					 * that they are the right color by
+					 * setting the video attributes from
+					 * the last character on the row.
+					 */
+					UpdateAttrs(blank);
+					DelChar(oLastChar - nLastChar);
+				}
+			}
+		}
+	}
+
+	/* update the code's internal representation */
+	if (screen_columns > firstChar)
+		memcpy( oldLine + firstChar,
+			newLine + firstChar,
+			(screen_columns - firstChar) * sizeof(chtype));
+}
+
+/*
+**	ClearScreen(blank)
+**
+**	Clear the physical screen and put cursor at home
+**
+*/
+
+static void ClearScreen(chtype blank)
+{
+	int	i, j;
+
+	T(("ClearScreen() called"));
+
+	if (clear_screen) {
+		UpdateAttrs(blank);
+		TPUTS_TRACE("clear_screen");
+		putp(clear_screen);
+		SP->_cursrow = SP->_curscol = 0;
+#ifdef POSITION_DEBUG
+		position_check(SP->_cursrow, SP->_curscol, "ClearScreen");
+#endif /* POSITION_DEBUG */
+	} else if (clr_eos) {
+		SP->_cursrow = SP->_curscol = -1;
+		GoTo(0,0);
+
+		UpdateAttrs(blank);
+		TPUTS_TRACE("clr_eos");
+		putp(clr_eos);
+	} else if (clr_eol) {
+		SP->_cursrow = SP->_curscol = -1;
+
+		for (i = 0; i < screen_lines; i++) {
+			GoTo(i, 0);
+			UpdateAttrs(blank);
+			TPUTS_TRACE("clr_eol");
+			putp(clr_eol);
+		}
+		GoTo(0,0);
+	} else {
+		T(("cannot clear screen"));
+		return;
+	}
+
+	for (i = 0; i < screen_lines; i++) {
+		for (j = 0; j < screen_columns; j++)
+			curscr->_line[i].text[j] = blank;
+	}
+
+	T(("screen cleared"));
+}
+
+/*
+**	InsStr(line, count)
+**
+**	Insert the count characters pointed to by line.
+**
+*/
+
+static int InsStr(chtype *line, int count)
+{
+	T(("InsStr(%p,%d) called", line, count));
+
+	/* Prefer parm_ich as it has the smallest cost - no need to shift
+	 * the whole line on each character. */
+	/* The order must match that of InsCharCost. */
+	if (parm_ich) {
+		TPUTS_TRACE("parm_ich");
+		tputs(tparm(parm_ich, count), count, _nc_outch);
+		while (count) {
+			PutAttrChar(*line);
+			line++;
+			count--;
+		}
+		return(OK);
+	} else if (enter_insert_mode  &&  exit_insert_mode) {
+		TPUTS_TRACE("enter_insert_mode");
+		putp(enter_insert_mode);
+		while (count) {
+			PutAttrChar(*line);
+			if (insert_padding)
+			{
+				TPUTS_TRACE("insert_padding");
+				putp(insert_padding);
+			}
+			line++;
+			count--;
+		}
+		TPUTS_TRACE("exit_insert_mode");
+		putp(exit_insert_mode);
+		return(OK);
+	} else {
+		while (count) {
+			TPUTS_TRACE("insert_character");
+			putp(insert_character);
+			PutAttrChar(*line);
+			if (insert_padding)
+			{
+				TPUTS_TRACE("insert_padding");
+				putp(insert_padding);
+			}
+			line++;
+			count--;
+		}
+		return(OK);
+	}
+}
+
+/*
+**	DelChar(count)
+**
+**	Delete count characters at current position
+**
+*/
+
+static void DelChar(int count)
+{
+	T(("DelChar(%d) called, position = (%d,%d)", count, newscr->_cury, newscr->_curx));
+
+	if (parm_dch) {
+		TPUTS_TRACE("parm_dch");
+		tputs(tparm(parm_dch, count), count, _nc_outch);
+	} else {
+		while (count--)
+		{
+			TPUTS_TRACE("delete_character");
+			putp(delete_character);
+		}
+	}
+}
+
+/*
+**	_nc_outstr(char *str)
+**
+**	Emit a string without waiting for update.
+*/
+
+void _nc_outstr(const char *str)
+{
+    FILE *ofp = SP ? SP->_ofp : stdout;
+
+    (void) fputs(str, ofp);
+    (void) fflush(ofp);
+
+#ifdef TRACE
+    _nc_outchars += strlen(str);
+#endif /* TRACE */
+}
+
+/*
+ * Physical-scrolling support
+ *
+ * This code was adapted from Keith Bostic's hardware scrolling
+ * support for 4.4BSD curses.  I (esr) translated it to use terminfo
+ * capabilities, narrowed the call interface slightly, and cleaned
+ * up some convoluted tests.  I also added support for the memory_above
+ * memory_below, and non_dest_scroll_region capabilities.
+ *
+ * For this code to work, we must have either
+ * change_scroll_region and scroll forward/reverse commands, or
+ * insert and delete line capabilities.
+ * When the scrolling region has been set, the cursor has to
+ * be at the last line of the region to make the scroll up
+ * happen, or on the first line of region to scroll down.
+ *
+ * This code makes one aesthetic decision in the opposite way from
+ * BSD curses.  BSD curses preferred pairs of il/dl operations
+ * over scrolls, allegedly because il/dl looked faster.  We, on
+ * the other hand, prefer scrolls because (a) they're just as fast
+ * on many terminals and (b) using them avoids bouncing an
+ * unchanged bottom section of the screen up and down, which is
+ * visually nasty.
+ *
+ * (lav): added more cases, used dl/il when bot==maxy and in csr case.
+ *
+ * I used assumption that capabilities il/il1/dl/dl1 work inside
+ * changed scroll region not shifting screen contents outside of it.
+ * If there are any terminals behaving different way, it would be
+ * necessary to add some conditions to scroll_csr_forward/backward.
+ */
+
+/* Try to scroll up assuming given csr (miny, maxy). Returns ERR on failure */
+static int scroll_csr_forward(int n, int top, int bot, int miny, int maxy, chtype blank)
+{
+    int i;
+
+    if (n == 1 && scroll_forward && top == miny && bot == maxy)
+    {
+	GoTo(bot, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("scroll_forward");
+	tputs(scroll_forward, 0, _nc_outch);
+    }
+    else if (n == 1 && delete_line && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("delete_line");
+	tputs(delete_line, 0, _nc_outch);
+    }
+    else if (parm_index && top == miny && bot == maxy)
+    {
+	GoTo(bot, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("parm_index");
+	tputs(tparm(parm_index, n, 0), n, _nc_outch);
+    }
+    else if (parm_delete_line && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("parm_delete_line");
+	tputs(tparm(parm_delete_line, n, 0), n, _nc_outch);
+    }
+    else if (scroll_forward && top == miny && bot == maxy)
+    {
+	GoTo(bot, 0);
+	UpdateAttrs(blank);
+	for (i = 0; i < n; i++)
+	{
+	    TPUTS_TRACE("scroll_forward");
+	    tputs(scroll_forward, 0, _nc_outch);
+	}
+    }
+    else if (delete_line && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	for (i = 0; i < n; i++)
+	{
+	    TPUTS_TRACE("delete_line");
+	    tputs(delete_line, 0, _nc_outch);
+	}
+    }
+    else
+	return ERR;
+
+    return OK;
+}
+
+/* Try to scroll down assuming given csr (miny, maxy). Returns ERR on failure */
+/* n > 0 */
+static int scroll_csr_backward(int n, int top, int bot, int miny, int maxy, chtype blank)
+{
+    int i;
+
+    if (n == 1 && scroll_reverse && top == miny && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("scroll_reverse");
+	tputs(scroll_reverse, 0, _nc_outch);
+    }
+    else if (n == 1 && insert_line && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("insert_line");
+	tputs(insert_line, 0, _nc_outch);
+    }
+    else if (parm_rindex && top == miny && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("parm_rindex");
+	tputs(tparm(parm_rindex, n, 0), n, _nc_outch);
+    }
+    else if (parm_insert_line && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("parm_insert_line");
+	tputs(tparm(parm_insert_line, n, 0), n, _nc_outch);
+    }
+    else if (scroll_reverse && top == miny && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	for (i = 0; i < n; i++)
+	{
+	    TPUTS_TRACE("scroll_reverse");
+	    tputs(scroll_reverse, 0, _nc_outch);
+	}
+    }
+    else if (insert_line && bot == maxy)
+    {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	for (i = 0; i < n; i++)
+	{
+	    TPUTS_TRACE("insert_line");
+	    tputs(insert_line, 0, _nc_outch);
+	}
+    }
+    else
+	return ERR;
+
+    return OK;
+}
+
+/* scroll by using delete_line at del and insert_line at ins */
+/* n > 0 */
+static int scroll_idl(int n, int del, int ins, chtype blank)
+{
+    int i;
+
+    if(!((parm_delete_line || delete_line) && (parm_insert_line || insert_line)))
+	return ERR;
+
+    GoTo(del, 0);
+    UpdateAttrs(blank);
+    if (n == 1 && delete_line)
+    {
+	TPUTS_TRACE("delete_line");
+	tputs(delete_line, 0, _nc_outch);
+    }
+    else if (parm_delete_line)
+    {
+	TPUTS_TRACE("parm_delete_line");
+	tputs(tparm(parm_delete_line, n, 0), n, _nc_outch);
+    }
+    else /* if (delete_line) */
+    {
+	for (i = 0; i < n; i++)
+	{
+	    TPUTS_TRACE("delete_line");
+	    tputs(delete_line, 0, _nc_outch);
+	}
+    }
+
+    GoTo(ins, 0);
+    UpdateAttrs(blank);
+    if (n == 1 && insert_line)
+    {
+	TPUTS_TRACE("insert_line");
+	tputs(insert_line, 0, _nc_outch);
+    }
+    else if (parm_insert_line)
+    {
+	TPUTS_TRACE("parm_insert_line");
+	tputs(tparm(parm_insert_line, n, 0), n, _nc_outch);
+    }
+    else /* if (insert_line) */
+    {
+	for (i = 0; i < n; i++)
+	{
+	    TPUTS_TRACE("insert_line");
+	    tputs(insert_line, 0, _nc_outch);
+	}
+    }
+
+    return OK;
+}
+
+int _nc_scrolln(int n, int top, int bot, int maxy)
+/* scroll region from top to bot by n lines */
+{
+    chtype blank=ClrBlank(stdscr);
+    int i;
+    bool cursor_saved=FALSE;
+    int res;
+
+    TR(TRACE_MOVE, ("mvcur_scrolln(%d, %d, %d, %d)", n, top, bot, maxy));
+
+#if USE_XMC_SUPPORT
+    /*
+     * If we scroll, we might remove a cookie.
+     */
+    if (magic_cookie_glitch > 0) {
+	return (ERR);
+    }
+#endif
+
+    if (n > 0) /* scroll up (forward) */
+    {
+	/*
+	 * Explicitly clear if stuff pushed off top of region might
+	 * be saved by the terminal.
+	 */
+	if (non_dest_scroll_region || (memory_above && top == 0)) {
+	    for (i = 0; i < n; i++)
+	    {
+		GoTo(i, 0);
+		ClrToEOL(BLANK);
+	    }
+	}
+
+	res = scroll_csr_forward(n, top, bot, 0, maxy, blank);
+
+	if (res == ERR && change_scroll_region)
+	{
+	    if ((((n==1 && scroll_forward) || parm_index)
+		 && (SP->_cursrow == bot || SP->_cursrow == bot-1))
+		&& save_cursor && restore_cursor)
+	    {
+		cursor_saved=TRUE;
+		TPUTS_TRACE("save_cursor");
+		tputs(save_cursor, 0, _nc_outch);
+	    }
+	    TPUTS_TRACE("change_scroll_region");
+	    tputs(tparm(change_scroll_region, top, bot), 0, _nc_outch);
+	    if (cursor_saved)
+	    {
+		TPUTS_TRACE("restore_cursor");
+		tputs(restore_cursor, 0, _nc_outch);
+	    }
+	    else
+	    {
+		SP->_cursrow = SP->_curscol = -1;
+	    }
+
+	    res = scroll_csr_forward(n, top, bot, top, bot, blank);
+
+	    TPUTS_TRACE("change_scroll_region");
+	    tputs(tparm(change_scroll_region, 0, maxy), 0, _nc_outch);
+	    SP->_cursrow = SP->_curscol = -1;
+	}
+
+	if (res == ERR && _nc_idlok)
+	    res = scroll_idl(n, top, bot-n+1, blank);
+    }
+    else /* (n < 0) - scroll down (backward) */
+    {
+	/*
+	 * Do explicit clear to end of region if it's possible that the
+	 * terminal might hold on to stuff we push off the end.
+	 */
+	if (non_dest_scroll_region || (memory_below && bot == maxy))
+	{
+	    if (bot == maxy && clr_eos)
+	    {
+		GoTo(maxy + n, 0);
+		ClrToEOS(BLANK);
+	    }
+	    else if (clr_eol)
+	    {
+		for (i = 0; i < -n; i++)
+		{
+		    GoTo(maxy + n + i, 0);
+		    ClrToEOL(BLANK);
+		}
+	    }
+	}
+
+	res = scroll_csr_backward(-n, top, bot, 0, maxy, blank);
+
+	if (res == ERR && change_scroll_region)
+	{
+	    if (top != 0 && (SP->_cursrow == top || SP->_cursrow == top-1)
+		&& save_cursor && restore_cursor)
+	    {
+		cursor_saved=TRUE;
+		TPUTS_TRACE("save_cursor");
+		tputs(save_cursor, 0, _nc_outch);
+	    }
+	    TPUTS_TRACE("change_scroll_region");
+	    tputs(tparm(change_scroll_region, top, bot), 0, _nc_outch);
+	    if (cursor_saved)
+	    {
+		TPUTS_TRACE("restore_cursor");
+		tputs(restore_cursor, 0, _nc_outch);
+	    }
+	    else
+	    {
+		SP->_cursrow = SP->_curscol = -1;
+	    }
+
+	    res = scroll_csr_backward(-n, top, bot, top, bot, blank);
+
+	    TPUTS_TRACE("change_scroll_region");
+	    tputs(tparm(change_scroll_region, 0, maxy), 0, _nc_outch);
+	    SP->_cursrow = SP->_curscol = -1;
+	}
+
+	if (res == ERR && _nc_idlok)
+	    res = scroll_idl(-n, bot+n+1, top, blank);
+    }
+
+    if (res == ERR)
+	return(ERR);
+
+    _nc_scroll_window(curscr, n, top, bot, blank);
+
+    /* shift hash values too - they can be reused */
+    _nc_scroll_oldhash(n, top, bot);
+
+    return(OK);
+}
+
+
+void _nc_screen_resume()
+{
+    /* make sure terminal is in a sane known state */
+    SP->_current_attr = A_NORMAL;
+    newscr->_clear = TRUE;
+
+    if (SP->_coloron == TRUE && orig_pair)
+	putp(orig_pair);
+    if (exit_attribute_mode)
+	putp(exit_attribute_mode);
+    else
+    {
+	/* turn off attributes */
+	if (exit_alt_charset_mode)
+	    putp(exit_alt_charset_mode);
+	if (exit_standout_mode)
+	    putp(exit_standout_mode);
+	if (exit_underline_mode)
+	    putp(exit_underline_mode);
+    }
+    if (exit_insert_mode)
+	putp(exit_insert_mode);
+    if (enter_am_mode && exit_am_mode)
+	putp(auto_right_margin ? enter_am_mode : exit_am_mode);
+}
+
+void _nc_screen_init()
+{
+    _nc_screen_resume();
+}
+
+/* wrap up screen handling */
+void _nc_screen_wrap()
+{
+    UpdateAttrs(A_NORMAL);
+}
+
+#if USE_XMC_SUPPORT
+void _nc_do_xmc_glitch(attr_t previous)
+{
+	attr_t chg = XMC_CHANGES(previous ^ SP->_current_attr);
+
+	while (chg != 0) {
+		if (chg & 1) {
+			SP->_curscol += magic_cookie_glitch;
+			if (SP->_curscol >= SP->_columns)
+				wrap_cursor();
+			T(("bumped to %d,%d after cookie", SP->_cursrow, SP->_curscol));
+		}
+		chg >>= 1;
+	}
+}
+#endif /* USE_XMC_SUPPORT */