diff --git a/ncurses/tty/tty_update.c b/ncurses/tty/tty_update.c
new file mode 100644
index 0000000..6a3a0c8
--- /dev/null
+++ b/ncurses/tty/tty_update.c
@@ -0,0 +1,1976 @@
+/****************************************************************************
+ * Copyright (c) 1998-2007,2008 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>                         *
+ *     and: Thomas E. Dickey                        1996-on                 *
+ ****************************************************************************/
+
+/*-----------------------------------------------------------------
+ *
+ *	lib_doupdate.c
+ *
+ * 	The routine doupdate() and its dependents.
+ * 	All physical output is concentrated here (except _nc_outch()
+  *	in lib_tputs.c).
+ *
+ *-----------------------------------------------------------------*/
+
+#include <curses.priv.h>
+
+#if defined __HAIKU__ && defined __BEOS__
+#undef __BEOS__
+#endif
+
+#ifdef __BEOS__
+#undef false
+#undef true
+#include <OS.h>
+#endif
+
+#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
+#elif HAVE_SELECT
+#if HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+#endif
+
+#include <ctype.h>
+#include <term.h>
+
+MODULE_ID("$Id: tty_update.c,v 1.246 2008/08/30 20:08:19 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
+
+#define FILL_BCE() (SP->_coloron && !SP->_default_color && !back_color_erase)
+
+static const NCURSES_CH_T blankchar = NewChar(BLANK_TEXT);
+static NCURSES_CH_T normal = NewChar(BLANK_TEXT);
+
+/*
+ * 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 NCURSES_INLINE NCURSES_CH_T ClrBlank(WINDOW *win);
+static int ClrBottom(int total);
+static void ClearScreen(NCURSES_CH_T blank);
+static void ClrUpdate(void);
+static void DelChar(int count);
+static void InsStr(NCURSES_CH_T * line, int count);
+static void TransformLine(int const lineno);
+
+#ifdef POSITION_DEBUG
+/****************************************************************************
+ *
+ * Debugging code.  Only works on ANSI-standard terminals.
+ *
+ ****************************************************************************/
+
+static void
+position_check(int expected_y, int expected_x, char *legend)
+/* check to see if the real cursor position matches the virtual */
+{
+    char buf[20];
+    char *s;
+    int y, x;
+
+    if (!_nc_tracing || (expected_y < 0 && expected_x < 0))
+	return;
+
+    _nc_flush();
+    memset(buf, '\0', sizeof(buf));
+    putp("\033[6n");		/* only works on ANSI-compatibles */
+    _nc_flush();
+    *(s = buf) = 0;
+    do {
+	int ask = sizeof(buf) - 1 - (s - buf);
+	int got = read(0, s, ask);
+	if (got == 0)
+	    break;
+	s += got;
+    } while (strchr(buf, 'R') == 0);
+    _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 (expected_x < 0)
+	    expected_x = x - 1;
+	if (expected_y < 0)
+	    expected_y = y - 1;
+	if (y - 1 != expected_y || x - 1 != expected_x) {
+	    beep();
+	    tputs(tparm("\033[%d;%dH", expected_y + 1, expected_x + 1), 1, _nc_outch);
+	    _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);
+	}
+    }
+}
+#else
+#define position_check(expected_y, expected_x, legend)	/* nothing */
+#endif /* POSITION_DEBUG */
+
+/****************************************************************************
+ *
+ * Optimized update code
+ *
+ ****************************************************************************/
+
+static NCURSES_INLINE void
+GoTo(int const row, int const col)
+{
+    TR(TRACE_MOVE, ("GoTo(%d, %d) from (%d, %d)",
+		    row, col, SP->_cursrow, SP->_curscol));
+
+    position_check(SP->_cursrow, SP->_curscol, "GoTo");
+
+    mvcur(SP->_cursrow, SP->_curscol, row, col);
+    position_check(SP->_cursrow, SP->_curscol, "GoTo2");
+}
+
+static NCURSES_INLINE void
+PutAttrChar(CARG_CH_T ch)
+{
+    int chlen = 1;
+    NCURSES_CH_T my_ch;
+    PUTC_DATA;
+    NCURSES_CH_T tilde;
+    NCURSES_CH_T attr = CHDEREF(ch);
+
+    TR(TRACE_CHARPUT, ("PutAttrChar(%s) at (%d, %d)",
+		       _tracech_t(ch),
+		       SP->_cursrow, SP->_curscol));
+#if USE_WIDEC_SUPPORT
+    /*
+     * If this is not a valid character, there is nothing more to do.
+     */
+    if (isWidecExt(CHDEREF(ch))) {
+	TR(TRACE_CHARPUT, ("...skip"));
+	return;
+    }
+    /*
+     * Determine the number of character cells which the 'ch' value will use
+     * on the screen.  It should be at least one.
+     */
+    if ((chlen = wcwidth(CharOf(CHDEREF(ch)))) <= 0) {
+	static const NCURSES_CH_T blank = NewChar(BLANK_TEXT);
+
+	/*
+	 * If the character falls into any of these special cases, do
+	 * not force the result to a blank:
+	 *
+	 * a) it is printable (this works around a bug in wcwidth()).
+	 * b) use_legacy_coding() has been called to modify the treatment
+	 *    of codes 128-255.
+	 * c) the acs_map[] has been initialized to allow codes 0-31
+	 *    to be rendered.  This supports Linux console's "PC"
+	 *    characters.  Codes 128-255 are allowed though this is
+	 *    not checked.
+	 */
+	if (is8bits(CharOf(CHDEREF(ch)))
+	    && (isprint(CharOf(CHDEREF(ch)))
+		|| (SP->_legacy_coding > 0 && CharOf(CHDEREF(ch)) >= 160)
+		|| (SP->_legacy_coding > 1 && CharOf(CHDEREF(ch)) >= 128)
+		|| (AttrOf(attr) & A_ALTCHARSET
+		    && ((CharOfD(ch) < ACS_LEN
+			 && SP->_acs_map != 0
+			 && SP->_acs_map[CharOfD(ch)] != 0)
+			|| (CharOfD(ch) >= 128))))) {
+	    ;
+	} else {
+	    ch = CHREF(blank);
+	    TR(TRACE_CHARPUT, ("forced to blank"));
+	}
+	chlen = 1;
+    }
+#endif
+
+    if ((AttrOf(attr) & A_ALTCHARSET)
+	&& SP->_acs_map != 0
+	&& CharOfD(ch) < ACS_LEN) {
+	my_ch = CHDEREF(ch);	/* work around const param */
+#if USE_WIDEC_SUPPORT
+	/*
+	 * This is crude & ugly, but works most of the time.  It checks if the
+	 * acs_chars string specified that we have a mapping for this
+	 * character, and uses the wide-character mapping when we expect the
+	 * normal one to be broken (by mis-design ;-).
+	 */
+	if (SP->_screen_acs_fix
+	    && SP->_screen_acs_map[CharOf(my_ch)]) {
+	    RemAttr(attr, A_ALTCHARSET);
+	    my_ch = _nc_wacs[CharOf(my_ch)];
+	}
+#endif
+	/*
+	 * If we (still) have alternate character set, it is the normal 8bit
+	 * flavor.  The _screen_acs_map[] array tells if the character was
+	 * really in acs_chars, needed because of the way wide/normal line
+	 * drawing flavors are integrated.
+	 */
+	if (AttrOf(attr) & A_ALTCHARSET) {
+	    int j = CharOfD(ch);
+	    chtype temp = UChar(SP->_acs_map[j]);
+
+	    if (!(SP->_screen_acs_map[j])) {
+		RemAttr(attr, A_ALTCHARSET);
+		if (temp == 0)
+		    temp = ' ';
+	    }
+	    if (temp != 0)
+		SetChar(my_ch, temp, AttrOf(attr));
+	}
+	ch = CHREF(my_ch);
+    }
+    if (tilde_glitch && (CharOfD(ch) == L('~'))) {
+	SetChar(tilde, L('`'), AttrOf(attr));
+	ch = CHREF(tilde);
+    }
+
+    UpdateAttrs(attr);
+#if !USE_WIDEC_SUPPORT
+    /* FIXME - we do this special case for signal handling, should see how to
+     * make it work for wide characters.
+     */
+    if (SP->_outch != 0) {
+	SP->_outch(UChar(ch));
+    } else
+#endif
+    {
+	PUTC(CHDEREF(ch), SP->_ofp);	/* macro's fastest... */
+	COUNT_OUTCHARS(1);
+    }
+    SP->_curscol += chlen;
+    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 defined(__BEOS__)
+	/*
+	 * BeOS's select() is declared in socket.h, so the configure script does
+	 * not see it.  That's just as well, since that function works only for
+	 * sockets.  This (using snooze and ioctl) was distilled from Be's patch
+	 * for ncurses which uses a separate thread to simulate select().
+	 *
+	 * FIXME: the return values from the ioctl aren't very clear if we get
+	 * interrupted.
+	 */
+	int n = 0;
+	int howmany = ioctl(0, 'ichr', &n);
+	if (howmany >= 0 && n > 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;
+	_nc_flush();
+    }
+    return FALSE;
+}
+
+/* put char at lower right corner */
+static void
+PutCharLR(const ARG_CH_T 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);
+	SP->_curscol--;
+	position_check(SP->_cursrow, SP->_curscol, "exit_am_mode");
+
+	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);
+	PutAttrChar(ch);
+	GoTo(screen_lines - 1, screen_columns - 2);
+	InsStr(newscr->_line[screen_lines - 1].text + screen_columns - 2, 1);
+    }
+}
+
+/*
+ * Wrap the cursor position, i.e., advance to the beginning of the next line.
+ */
+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++;
+	/*
+	 * We've actually moved - but may have to work around problems with
+	 * video attributes not working.
+	 */
+	if (!move_standout_mode && AttrOf(SCREEN_ATTRS(SP))) {
+	    TR(TRACE_CHARPUT, ("turning off (%#lx) %s before wrapping",
+			       (unsigned long) AttrOf(SCREEN_ATTRS(SP)),
+			       _traceattr(AttrOf(SCREEN_ATTRS(SP)))));
+	    (void) VIDATTR(A_NORMAL, 0);
+	}
+    } else {
+	SP->_curscol--;
+    }
+    position_check(SP->_cursrow, SP->_curscol, "wrap_cursor");
+}
+
+static NCURSES_INLINE void
+PutChar(const ARG_CH_T 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();
+
+    position_check(SP->_cursrow, SP->_curscol, "PutChar");
+}
+
+/*
+ * Check whether the given character can be output by clearing commands.  This
+ * includes test for being a space and not including any 'bad' attributes, such
+ * as A_REVERSE.  All attribute flags which don't affect appearance of a space
+ * or can be output by clearing (A_COLOR in case of bce-terminal) are excluded.
+ */
+static NCURSES_INLINE bool
+can_clear_with(ARG_CH_T ch)
+{
+    if (!back_color_erase && SP->_coloron) {
+#if NCURSES_EXT_FUNCS
+	int pair;
+
+	if (!SP->_default_color)
+	    return FALSE;
+	if (SP->_default_fg != C_MASK || SP->_default_bg != C_MASK)
+	    return FALSE;
+	if ((pair = GetPair(CHDEREF(ch))) != 0) {
+	    short fg, bg;
+	    pair_content(pair, &fg, &bg);
+	    if (fg != C_MASK || bg != C_MASK)
+		return FALSE;
+	}
+#else
+	if (AttrOfD(ch) & A_COLOR)
+	    return FALSE;
+#endif
+    }
+    return (ISBLANK(CHDEREF(ch)) &&
+	    (AttrOfD(ch) & ~(NONBLANK_ATTR | A_COLOR)) == BLANK_ATTR);
+}
+
+/*
+ * 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 NCURSES_CH_T * ntext, int num)
+{
+    int i;
+
+    TR(TRACE_CHARPUT, ("EmitRange %d:%s", num, _nc_viscbuf(ntext, num)));
+
+    if (erase_chars || repeat_char) {
+	while (num > 0) {
+	    int runcount;
+	    NCURSES_CH_T ntext0;
+
+	    while (num > 1 && !CharEq(ntext[0], ntext[1])) {
+		PutChar(CHREF(ntext[0]));
+		ntext++;
+		num--;
+	    }
+	    ntext0 = ntext[0];
+	    if (num == 1) {
+		PutChar(CHREF(ntext0));
+		return 0;
+	    }
+	    runcount = 2;
+
+	    while (runcount < num && CharEq(ntext[runcount], ntext0))
+		runcount++;
+
+	    /*
+	     * The cost expression in the middle isn't exactly right.
+	     * _cup_ch_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_ch_cost
+		&& can_clear_with(CHREF(ntext0))) {
+		UpdateAttrs(ntext0);
+		putp(TPARM_1(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);
+		tputs(TPARM_2(repeat_char, CharOf(ntext0), rep_count),
+		      rep_count, _nc_outch);
+		SP->_curscol += rep_count;
+
+		if (wrap_possible)
+		    PutChar(CHREF(ntext0));
+	    } else {
+		for (i = 0; i < runcount; i++)
+		    PutChar(CHREF(ntext[i]));
+	    }
+	    ntext += runcount;
+	    num -= runcount;
+	}
+	return 0;
+    }
+
+    for (i = 0; i < num; i++)
+	PutChar(CHREF(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 NCURSES_CH_T * otext,
+	 const NCURSES_CH_T * ntext,
+	 int row,
+	 int first, int last)
+{
+    int i, j, same;
+
+    TR(TRACE_CHARPUT, ("PutRange(%p, %p, %d, %d, %d)",
+		       otext, ntext, row, first, last));
+
+    if (otext != ntext
+	&& (last - first + 1) > SP->_inline_cost) {
+	for (j = first, same = 0; j <= last; j++) {
+	    if (!same && isWidecExt(otext[j]))
+		continue;
+	    if (CharEq(otext[j], ntext[j])) {
+		same++;
+	    } else {
+		if (same > SP->_inline_cost) {
+		    EmitRange(ntext + first, j - same - first);
+		    GoTo(row, first = j);
+		}
+		same = 0;
+	    }
+	}
+	i = EmitRange(ntext + first, j - same - first);
+	/*
+	 * Always return 1 for the next GoTo() after a PutRange() if we found
+	 * identical characters at end of interval
+	 */
+	return (same == 0 ? i : 1);
+    }
+    return EmitRange(ntext + first, last - first + 1);
+}
+
+/* leave unbracketed here so 'indent' works */
+#define MARK_NOCHANGE(win,row) \
+		win->_line[row].firstchar = _NOCHANGE; \
+		win->_line[row].lastchar = _NOCHANGE; \
+		if_USE_SCROLL_HINTS(win->_line[row].oldindex = row)
+
+NCURSES_EXPORT(int)
+doupdate(void)
+{
+    int i;
+    int nonempty;
+#if USE_TRACE_TIMES
+    struct tms before, after;
+#endif /* USE_TRACE_TIMES */
+
+    T((T_CALLED("doupdate()")));
+
+    if (curscr == 0
+	|| newscr == 0)
+	returnCode(ERR);
+
+#ifdef TRACE
+    if (USE_TRACEF(TRACE_UPDATE)) {
+	if (curscr->_clear)
+	    _tracef("curscr is clear");
+	else
+	    _tracedump("curscr", curscr);
+	_tracedump("newscr", newscr);
+	_nc_unlock_global(tracef);
+    }
+#endif /* TRACE */
+
+    _nc_signal_handler(FALSE);
+
+    if (SP->_fifohold)
+	SP->_fifohold--;
+
+#if USE_SIZECHANGE
+    if (SP->_endwin || _nc_handle_sigwinch(SP)) {
+	/*
+	 * 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(SP);
+    }
+#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 */
+    RESET_OUTCHARS();
+    (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;
+		NCURSES_CH_T *thisline = newscr->_line[i].text;
+		attr_t thisattr = AttrOf(thisline[j]) & SP->_xmc_triggers;
+		attr_t turnon = thisattr & ~rattr;
+
+		/* is an attribute turned on here? */
+		if (turnon == 0) {
+		    rattr = thisattr;
+		    continue;
+		}
+
+		TR(TRACE_ATTRS, ("At (%d, %d): from %s...", i, j, _traceattr(rattr)));
+		TR(TRACE_ATTRS, ("...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) & SP->_xmc_triggers))
+		if (ISBLANK(thisline[j]) && SAFE(turnon)) {
+		    RemAttr(thisline[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
+			|| !ISBLANK(thisline[j - k])
+			|| !SAFE(AttrOf(thisline[j - k]))) {
+			failed = TRUE;
+			TR(TRACE_ATTRS, ("No room at start in %d,%d%s%s",
+					 i, j - k,
+					 (ISBLANK(thisline[j - k])
+					  ? ""
+					  : ":nonblank"),
+					 (SAFE(AttrOf(thisline[j - k]))
+					  ? ""
+					  : ":unsafe")));
+			break;
+		    }
+		}
+		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++) {
+			    attr_t testattr = AttrOf(newscr->_line[m].text[n]);
+			    if ((testattr & SP->_xmc_triggers) == rattr) {
+				end_onscreen = TRUE;
+				TR(TRACE_ATTRS,
+				   ("Range attributed with %s ends at (%d, %d)",
+				    _traceattr(turnon), m, n));
+				goto foundit;
+			    }
+			}
+			n = 0;
+		    }
+		    TR(TRACE_ATTRS,
+		       ("Range attributed with %s ends offscreen",
+			_traceattr(turnon)));
+		  foundit:;
+
+		    if (end_onscreen) {
+			NCURSES_CH_T *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
+			       && ISBLANK(lastline[n])
+			       && SAFE(AttrOf(lastline[n]))) {
+			    RemAttr(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
+				|| !ISBLANK(lastline[n + k])
+				|| !SAFE(AttrOf(lastline[n + k]))) {
+				failed = TRUE;
+				TR(TRACE_ATTRS,
+				   ("No room at end in %d,%d%s%s",
+				    i, j - k,
+				    (ISBLANK(lastline[n + k])
+				     ? ""
+				     : ":nonblank"),
+				    (SAFE(AttrOf(lastline[n + k]))
+				     ? ""
+				     : ":unsafe")));
+				break;
+			    }
+			}
+		    }
+		}
+
+		if (failed) {
+		    int p, q = j;
+
+		    TR(TRACE_ATTRS,
+		       ("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++) {
+			    attr_t testattr = AttrOf(newscr->_line[p].text[q]);
+			    if ((testattr & SP->_xmc_triggers) == rattr)
+				goto foundend;
+			    RemAttr(newscr->_line[p].text[q], turnon);
+			}
+			q = 0;
+		    }
+		  foundend:;
+		} else {
+		    TR(TRACE_ATTRS,
+		       ("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++)
+			AddAttr(thisline[j - k], turnon);
+		}
+
+		rattr = thisattr;
+	    }
+	}
+
+#ifdef TRACE
+	/* show altered highlights after magic-cookie check */
+	if (USE_TRACEF(TRACE_UPDATE)) {
+	    _tracef("After magic-cookie check...");
+	    _tracedump("newscr", newscr);
+	    _nc_unlock_global(tracef);
+	}
+#endif /* TRACE */
+    }
+#endif /* USE_XMC_SUPPORT */
+
+    nonempty = 0;
+    if (curscr->_clear || newscr->_clear) {	/* force refresh ? */
+	ClrUpdate();
+	curscr->_clear = FALSE;	/* reset flag */
+	newscr->_clear = FALSE;	/* reset flag */
+    } 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);
+
+	TR(TRACE_UPDATE, ("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:
+    /*
+     * We would like to keep the physical screen in normal mode in case we get
+     * other processes writing to the screen.  This goal cannot be met for
+     * magic cookies since it interferes with attributes that may propagate
+     * past the current position.
+     */
+#if USE_XMC_SUPPORT
+    if (magic_cookie_glitch != 0)
+#endif
+	UpdateAttrs(normal);
+
+    _nc_flush();
+    WINDOW_ATTRS(curscr) = WINDOW_ATTRS(newscr);
+
+#if USE_TRACE_TIMES
+    (void) times(&after);
+    TR(TRACE_TIMES,
+       ("Update cost: %ld chars, %ld clocks system time, %ld clocks user time",
+	_nc_outchars,
+	(long) (after.tms_stime - before.tms_stime),
+	(long) (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))->_nc_bkgd)
+
+static NCURSES_INLINE NCURSES_CH_T
+ClrBlank(WINDOW *win)
+{
+    NCURSES_CH_T blank = blankchar;
+    if (back_color_erase)
+	AddAttr(blank, (AttrOf(BCE_BKGD(win)) & BCE_ATTRS));
+    return blank;
+}
+
+/*
+**	ClrUpdate()
+**
+**	Update by clearing and redrawing the entire screen.
+**
+*/
+
+static void
+ClrUpdate(void)
+{
+    int i;
+    NCURSES_CH_T blank = ClrBlank(stdscr);
+    int nonempty = min(screen_lines, newscr->_maxy + 1);
+
+    TR(TRACE_UPDATE, (T_CALLED("ClrUpdate")));
+
+    ClearScreen(blank);
+
+    TR(TRACE_UPDATE, ("updating screen from scratch"));
+
+    nonempty = ClrBottom(nonempty);
+
+    for (i = 0; i < nonempty; i++)
+	TransformLine(i);
+
+    TR(TRACE_UPDATE, (T_RETURN("")));
+}
+
+/*
+**	ClrToEOL(blank)
+**
+**	Clear to end of current line, starting at the cursor position
+*/
+
+static void
+ClrToEOL(NCURSES_CH_T blank, bool needclear)
+{
+    int j;
+
+    if (curscr != 0
+	&& SP->_cursrow >= 0) {
+	for (j = SP->_curscol; j < screen_columns; j++) {
+	    if (j >= 0) {
+		NCURSES_CH_T *cp = &(curscr->_line[SP->_cursrow].text[j]);
+
+		if (!CharEq(*cp, blank)) {
+		    *cp = blank;
+		    needclear = TRUE;
+		}
+	    }
+	}
+    } else {
+	needclear = TRUE;
+    }
+
+    if (needclear) {
+	UpdateAttrs(blank);
+	TPUTS_TRACE("clr_eol");
+	if (clr_eol && SP->_el_cost <= (screen_columns - SP->_curscol)) {
+	    putp(clr_eol);
+	} else {
+	    int count = (screen_columns - SP->_curscol);
+	    while (count-- > 0)
+		PutChar(CHREF(blank));
+	}
+    }
+}
+
+/*
+**	ClrToEOS(blank)
+**
+**	Clear to end of screen, starting at the cursor position
+*/
+
+static void
+ClrToEOS(NCURSES_CH_T blank)
+{
+    int row, col;
+
+    row = SP->_cursrow;
+    col = SP->_curscol;
+
+    UpdateAttrs(blank);
+    TPUTS_TRACE("clr_eos");
+    tputs(clr_eos, screen_lines - row, _nc_outch);
+
+    while (col < screen_columns)
+	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)
+{
+    int row;
+    int col;
+    int top = total;
+    int last = min(screen_columns, newscr->_maxx + 1);
+    NCURSES_CH_T blank = newscr->_line[total - 1].text[last - 1];
+    bool ok;
+
+    if (clr_eos && can_clear_with(CHREF(blank))) {
+
+	for (row = total - 1; row >= 0; row--) {
+	    for (col = 0, ok = TRUE; ok && col < last; col++) {
+		ok = (CharEq(newscr->_line[row].text[col], blank));
+	    }
+	    if (!ok)
+		break;
+
+	    for (col = 0; ok && col < last; col++) {
+		ok = (CharEq(curscr->_line[row].text[col], blank));
+	    }
+	    if (!ok)
+		top = row;
+	}
+
+	/* don't use clr_eos for just one line if clr_eol available */
+	if (top < total) {
+	    GoTo(top, 0);
+	    ClrToEOS(blank);
+	    if (SP->oldhash && SP->newhash) {
+		for (row = top; row < screen_lines; row++)
+		    SP->oldhash[row] = SP->newhash[row];
+	    }
+	}
+    }
+    return top;
+}
+
+#if USE_XMC_SUPPORT
+#if USE_WIDEC_SUPPORT
+#define check_xmc_transition(a, b) \
+    ((((a)->attr ^ (b)->attr) & ~((a)->attr) & SP->_xmc_triggers) != 0)
+#define xmc_turn_on(a,b) check_xmc_transition(&(a), &(b))
+#else
+#define xmc_turn_on(a,b) ((((a)^(b)) & ~(a) & SP->_xmc_triggers) != 0)
+#endif
+
+#define xmc_new(r,c) newscr->_line[r].text[c]
+#define xmc_turn_off(a,b) xmc_turn_on(b,a)
+#endif /* USE_XMC_SUPPORT */
+
+/*
+**	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;
+    NCURSES_CH_T *newLine = newscr->_line[lineno].text;
+    NCURSES_CH_T *oldLine = curscr->_line[lineno].text;
+    int n;
+    bool attrchanged = FALSE;
+
+    TR(TRACE_UPDATE, (T_CALLED("TransformLine(%d)"), lineno));
+
+    /* copy new hash value to old one */
+    if (SP->oldhash && SP->newhash)
+	SP->oldhash[lineno] = SP->newhash[lineno];
+
+    /*
+     * If we have colors, there is the possibility of having two color pairs
+     * that display as the same colors.  For instance, Lynx does this.  Check
+     * for this case, and update the old line with the new line's colors when
+     * they are equivalent.
+     */
+    if (SP->_coloron) {
+	int oldPair;
+	int newPair;
+
+	for (n = 0; n < screen_columns; n++) {
+	    if (!CharEq(newLine[n], oldLine[n])) {
+		oldPair = GetPair(oldLine[n]);
+		newPair = GetPair(newLine[n]);
+		if (oldPair != newPair
+		    && unColor(oldLine[n]) == unColor(newLine[n])) {
+		    if (oldPair < COLOR_PAIRS
+			&& newPair < COLOR_PAIRS
+			&& SP->_color_pairs[oldPair] == SP->_color_pairs[newPair]) {
+			SetPair(oldLine[n], GetPair(newLine[n]));
+		    }
+		}
+	    }
+	}
+    }
+
+    if (ceol_standout_glitch && clr_eol) {
+	firstChar = 0;
+	while (firstChar < screen_columns) {
+	    if (!SameAttrOf(newLine[firstChar], oldLine[firstChar])) {
+		attrchanged = TRUE;
+		break;
+	    }
+	    firstChar++;
+	}
+    }
+
+    firstChar = 0;
+
+    if (attrchanged) {		/* we may have to disregard the whole line */
+	GoTo(lineno, firstChar);
+	ClrToEOL(ClrBlank(curscr), FALSE);
+	PutRange(oldLine, newLine, lineno, 0, (screen_columns - 1));
+#if USE_XMC_SUPPORT
+
+	/*
+	 * 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 (ISBLANK(newLine[n])
+		&& ((n > 0
+		     && xmc_turn_on(newLine[n - 1], newLine[n]))
+		    || (n == 0
+			&& lineno > 0
+			&& xmc_turn_on(xmc_new(lineno - 1, screen_columns - 1),
+				       newLine[n])))) {
+		n = m;
+	    }
+
+	    PutChar(CHREF(newLine[n]));
+
+	    /* check for turn-off:
+	     * If we are writing an attributed non-blank, where the
+	     * next cell is blank, and not attributed.
+	     */
+	    if (!ISBLANK(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], xmc_new(lineno + 1, 0))))) {
+		n = m;
+	    }
+
+	}
+#endif
+    } else {
+	NCURSES_CH_T blank;
+
+	/* it may be cheap to clear leading whitespace with clr_bol */
+	blank = newLine[0];
+	if (clr_bol && can_clear_with(CHREF(blank))) {
+	    int oFirstChar, nFirstChar;
+
+	    for (oFirstChar = 0; oFirstChar < screen_columns; oFirstChar++)
+		if (!CharEq(oldLine[oFirstChar], blank))
+		    break;
+	    for (nFirstChar = 0; nFirstChar < screen_columns; nFirstChar++)
+		if (!CharEq(newLine[nFirstChar], blank))
+		    break;
+
+	    if (nFirstChar == oFirstChar) {
+		firstChar = nFirstChar;
+		/* find the first differing character */
+		while (firstChar < screen_columns
+		       && CharEq(newLine[firstChar], oldLine[firstChar]))
+		    firstChar++;
+	    } else if (oFirstChar > nFirstChar) {
+		firstChar = nFirstChar;
+	    } else {		/* oFirstChar < nFirstChar */
+		firstChar = oFirstChar;
+		if (SP->_el1_cost < nFirstChar - oFirstChar) {
+		    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;
+		}
+	    }
+	} else {
+	    /* find the first differing character */
+	    while (firstChar < screen_columns
+		   && CharEq(newLine[firstChar], oldLine[firstChar]))
+		firstChar++;
+	}
+	/* if there wasn't one, we're done */
+	if (firstChar >= screen_columns) {
+	    TR(TRACE_UPDATE, (T_RETURN("")));
+	    return;
+	}
+
+	blank = newLine[screen_columns - 1];
+
+	if (!can_clear_with(CHREF(blank))) {
+	    /* find the last differing character */
+	    nLastChar = screen_columns - 1;
+
+	    while (nLastChar > firstChar
+		   && CharEq(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(NCURSES_CH_T));
+	    }
+	    TR(TRACE_UPDATE, (T_RETURN("")));
+	    return;
+	}
+
+	/* find last non-blank character on old line */
+	oLastChar = screen_columns - 1;
+	while (oLastChar > firstChar && CharEq(oldLine[oLastChar], blank))
+	    oLastChar--;
+
+	/* find last non-blank character on new line */
+	nLastChar = screen_columns - 1;
+	while (nLastChar > firstChar && CharEq(newLine[nLastChar], blank))
+	    nLastChar--;
+
+	if ((nLastChar == firstChar)
+	    && (SP->_el_cost < (oLastChar - nLastChar))) {
+	    GoTo(lineno, firstChar);
+	    if (!CharEq(newLine[firstChar], blank))
+		PutChar(CHREF(newLine[firstChar]));
+	    ClrToEOL(blank, FALSE);
+	} else if ((nLastChar != oLastChar)
+		   && (!CharEq(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, FALSE);
+	    } 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 */
+	    /* can be -1 if no characters differ */
+	    while (CharEq(newLine[nLastChar], oldLine[oLastChar])) {
+		/* don't split a wide char */
+		if (isWidecExt(newLine[nLastChar]) &&
+		    !CharEq(newLine[nLastChar - 1], oldLine[oLastChar - 1]))
+		    break;
+		nLastChar--;
+		oLastChar--;
+		if (nLastChar == -1 || oLastChar == -1)
+		    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);
+#if USE_WIDEC_SUPPORT
+		while (isWidecExt(newLine[n + 1]) && n) {
+		    --n;
+		    --oLastChar;
+		}
+#endif
+		GoTo(lineno, n + 1);
+		if ((nLastChar < nLastNonblank)
+		    || 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, FALSE);
+		} 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(NCURSES_CH_T));
+    TR(TRACE_UPDATE, (T_RETURN("")));
+    return;
+}
+
+/*
+**	ClearScreen(blank)
+**
+**	Clear the physical screen and put cursor at home
+**
+*/
+
+static void
+ClearScreen(NCURSES_CH_T blank)
+{
+    int i, j;
+    bool fast_clear = (clear_screen || clr_eos || clr_eol);
+
+    TR(TRACE_UPDATE, ("ClearScreen() called"));
+
+#if NCURSES_EXT_FUNCS
+    if (SP->_coloron
+	&& !SP->_default_color) {
+	_nc_do_color(GET_SCREEN_PAIR(SP), 0, FALSE, _nc_outch);
+	if (!back_color_erase) {
+	    fast_clear = FALSE;
+	}
+    }
+#endif
+
+    if (fast_clear) {
+	if (clear_screen) {
+	    UpdateAttrs(blank);
+	    TPUTS_TRACE("clear_screen");
+	    putp(clear_screen);
+	    SP->_cursrow = SP->_curscol = 0;
+	    position_check(SP->_cursrow, SP->_curscol, "ClearScreen");
+	} else if (clr_eos) {
+	    SP->_cursrow = SP->_curscol = -1;
+	    GoTo(0, 0);
+
+	    UpdateAttrs(blank);
+	    TPUTS_TRACE("clr_eos");
+	    tputs(clr_eos, screen_lines, _nc_outch);
+	} else if (clr_eol) {
+	    SP->_cursrow = SP->_curscol = -1;
+
+	    UpdateAttrs(blank);
+	    for (i = 0; i < screen_lines; i++) {
+		GoTo(i, 0);
+		TPUTS_TRACE("clr_eol");
+		putp(clr_eol);
+	    }
+	    GoTo(0, 0);
+	}
+    } else {
+	UpdateAttrs(blank);
+	for (i = 0; i < screen_lines; i++) {
+	    GoTo(i, 0);
+	    for (j = 0; j < screen_columns; j++)
+		PutChar(CHREF(blank));
+	}
+	GoTo(0, 0);
+    }
+
+    for (i = 0; i < screen_lines; i++) {
+	for (j = 0; j < screen_columns; j++)
+	    curscr->_line[i].text[j] = blank;
+    }
+
+    TR(TRACE_UPDATE, ("screen cleared"));
+}
+
+/*
+**	InsStr(line, count)
+**
+**	Insert the count characters pointed to by line.
+**
+*/
+
+static void
+InsStr(NCURSES_CH_T * line, int count)
+{
+    TR(TRACE_UPDATE, ("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_1(parm_ich, count), count, _nc_outch);
+	while (count) {
+	    PutAttrChar(CHREF(*line));
+	    line++;
+	    count--;
+	}
+    } else if (enter_insert_mode && exit_insert_mode) {
+	TPUTS_TRACE("enter_insert_mode");
+	putp(enter_insert_mode);
+	while (count) {
+	    PutAttrChar(CHREF(*line));
+	    if (insert_padding) {
+		TPUTS_TRACE("insert_padding");
+		putp(insert_padding);
+	    }
+	    line++;
+	    count--;
+	}
+	TPUTS_TRACE("exit_insert_mode");
+	putp(exit_insert_mode);
+    } else {
+	while (count) {
+	    TPUTS_TRACE("insert_character");
+	    putp(insert_character);
+	    PutAttrChar(CHREF(*line));
+	    if (insert_padding) {
+		TPUTS_TRACE("insert_padding");
+		putp(insert_padding);
+	    }
+	    line++;
+	    count--;
+	}
+    }
+    position_check(SP->_cursrow, SP->_curscol, "InsStr");
+}
+
+/*
+**	DelChar(count)
+**
+**	Delete count characters at current position
+**
+*/
+
+static void
+DelChar(int count)
+{
+    int n;
+
+    TR(TRACE_UPDATE, ("DelChar(%d) called, position = (%ld,%ld)",
+		      count,
+		      (long) newscr->_cury,
+		      (long) newscr->_curx));
+
+    if (parm_dch) {
+	TPUTS_TRACE("parm_dch");
+	tputs(TPARM_1(parm_dch, count), count, _nc_outch);
+    } else {
+	for (n = 0; n < count; n++) {
+	    TPUTS_TRACE("delete_character");
+	    putp(delete_character);
+	}
+    }
+}
+
+/*
+ * 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, NCURSES_CH_T blank)
+{
+    int i;
+
+    if (n == 1 && scroll_forward && top == miny && bot == maxy) {
+	GoTo(bot, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("scroll_forward");
+	putp(scroll_forward);
+    } else if (n == 1 && delete_line && bot == maxy) {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("delete_line");
+	putp(delete_line);
+    } else if (parm_index && top == miny && bot == maxy) {
+	GoTo(bot, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("parm_index");
+	tputs(TPARM_2(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_2(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");
+	    putp(scroll_forward);
+	}
+    } else if (delete_line && bot == maxy) {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	for (i = 0; i < n; i++) {
+	    TPUTS_TRACE("delete_line");
+	    putp(delete_line);
+	}
+    } else
+	return ERR;
+
+#if NCURSES_EXT_FUNCS
+    if (FILL_BCE()) {
+	int j;
+	for (i = 0; i < n; i++) {
+	    GoTo(bot - i, 0);
+	    for (j = 0; j < screen_columns; j++)
+		PutChar(CHREF(blank));
+	}
+    }
+#endif
+    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,
+		    NCURSES_CH_T blank)
+{
+    int i;
+
+    if (n == 1 && scroll_reverse && top == miny && bot == maxy) {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("scroll_reverse");
+	putp(scroll_reverse);
+    } else if (n == 1 && insert_line && bot == maxy) {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("insert_line");
+	putp(insert_line);
+    } else if (parm_rindex && top == miny && bot == maxy) {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	TPUTS_TRACE("parm_rindex");
+	tputs(TPARM_2(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_2(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");
+	    putp(scroll_reverse);
+	}
+    } else if (insert_line && bot == maxy) {
+	GoTo(top, 0);
+	UpdateAttrs(blank);
+	for (i = 0; i < n; i++) {
+	    TPUTS_TRACE("insert_line");
+	    putp(insert_line);
+	}
+    } else
+	return ERR;
+
+#if NCURSES_EXT_FUNCS
+    if (FILL_BCE()) {
+	int j;
+	for (i = 0; i < n; i++) {
+	    GoTo(top + i, 0);
+	    for (j = 0; j < screen_columns; j++)
+		PutChar(CHREF(blank));
+	}
+    }
+#endif
+    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, NCURSES_CH_T 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");
+	putp(delete_line);
+    } else if (parm_delete_line) {
+	TPUTS_TRACE("parm_delete_line");
+	tputs(TPARM_2(parm_delete_line, n, 0), n, _nc_outch);
+    } else {			/* if (delete_line) */
+	for (i = 0; i < n; i++) {
+	    TPUTS_TRACE("delete_line");
+	    putp(delete_line);
+	}
+    }
+
+    GoTo(ins, 0);
+    UpdateAttrs(blank);
+    if (n == 1 && insert_line) {
+	TPUTS_TRACE("insert_line");
+	putp(insert_line);
+    } else if (parm_insert_line) {
+	TPUTS_TRACE("parm_insert_line");
+	tputs(TPARM_2(parm_insert_line, n, 0), n, _nc_outch);
+    } else {			/* if (insert_line) */
+	for (i = 0; i < n; i++) {
+	    TPUTS_TRACE("insert_line");
+	    putp(insert_line);
+	}
+    }
+
+    return OK;
+}
+
+/*
+ * Note:  some terminals require the cursor to be within the scrolling margins
+ * before setting them.  Generally, the cursor must be at the appropriate end
+ * of the scrolling margins when issuing an indexing operation (it is not
+ * apparent whether it must also be at the left margin; we do this just to be
+ * safe).  To make the related cursor movement a little faster, we use the
+ * save/restore cursor capabilities if the terminal has them.
+ */
+NCURSES_EXPORT(int)
+_nc_scrolln(int n, int top, int bot, int maxy)
+/* scroll region from top to bot by n lines */
+{
+    NCURSES_CH_T 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.
+	 */
+	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");
+		putp(save_cursor);
+	    }
+	    TPUTS_TRACE("change_scroll_region");
+	    putp(TPARM_2(change_scroll_region, top, bot));
+	    if (cursor_saved) {
+		TPUTS_TRACE("restore_cursor");
+		putp(restore_cursor);
+	    } else {
+		SP->_cursrow = SP->_curscol = -1;
+	    }
+
+	    res = scroll_csr_forward(n, top, bot, top, bot, blank);
+
+	    TPUTS_TRACE("change_scroll_region");
+	    putp(TPARM_2(change_scroll_region, 0, maxy));
+	    SP->_cursrow = SP->_curscol = -1;
+	}
+
+	if (res == ERR && _nc_idlok)
+	    res = scroll_idl(n, top, bot - n + 1, blank);
+
+	/*
+	 * Clear the newly shifted-in text.
+	 */
+	if (res != ERR
+	    && (non_dest_scroll_region || (memory_below && bot == maxy))) {
+	    static const NCURSES_CH_T blank2 = NewChar(BLANK_TEXT);
+	    if (bot == maxy && clr_eos) {
+		GoTo(bot - n + 1, 0);
+		ClrToEOS(blank2);
+	    } else {
+		for (i = 0; i < n; i++) {
+		    GoTo(bot - i, 0);
+		    ClrToEOL(blank2, FALSE);
+		}
+	    }
+	}
+
+    } else {			/* (n < 0) - scroll down (backward) */
+	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");
+		putp(save_cursor);
+	    }
+	    TPUTS_TRACE("change_scroll_region");
+	    putp(TPARM_2(change_scroll_region, top, bot));
+	    if (cursor_saved) {
+		TPUTS_TRACE("restore_cursor");
+		putp(restore_cursor);
+	    } else {
+		SP->_cursrow = SP->_curscol = -1;
+	    }
+
+	    res = scroll_csr_backward(-n, top, bot, top, bot, blank);
+
+	    TPUTS_TRACE("change_scroll_region");
+	    putp(TPARM_2(change_scroll_region, 0, maxy));
+	    SP->_cursrow = SP->_curscol = -1;
+	}
+
+	if (res == ERR && _nc_idlok)
+	    res = scroll_idl(-n, bot + n + 1, top, blank);
+
+	/*
+	 * Clear the newly shifted-in text.
+	 */
+	if (res != ERR
+	    && (non_dest_scroll_region || (memory_above && top == 0))) {
+	    static const NCURSES_CH_T blank2 = NewChar(BLANK_TEXT);
+	    for (i = 0; i < -n; i++) {
+		GoTo(i + top, 0);
+		ClrToEOL(blank2, FALSE);
+	    }
+	}
+    }
+
+    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);
+}
+
+NCURSES_EXPORT(void)
+_nc_screen_resume(void)
+{
+    /* make sure terminal is in a sane known state */
+    SetAttr(SCREEN_ATTRS(SP), A_NORMAL);
+    newscr->_clear = TRUE;
+
+    /* reset color pairs and definitions */
+    if (SP->_coloron || SP->_color_defs)
+	_nc_reset_colors();
+
+    /* restore user-defined colors, if any */
+    if (SP->_color_defs < 0) {
+	int n;
+	SP->_color_defs = -(SP->_color_defs);
+	for (n = 0; n < SP->_color_defs; ++n) {
+	    if (SP->_color_table[n].init) {
+		init_color(n,
+			   SP->_color_table[n].r,
+			   SP->_color_table[n].g,
+			   SP->_color_table[n].b);
+	    }
+	}
+    }
+
+    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);
+}
+
+NCURSES_EXPORT(void)
+_nc_screen_init(void)
+{
+    _nc_screen_resume();
+}
+
+/* wrap up screen handling */
+NCURSES_EXPORT(void)
+_nc_screen_wrap(void)
+{
+    UpdateAttrs(normal);
+#if NCURSES_EXT_FUNCS
+    if (SP->_coloron
+	&& !SP->_default_color) {
+	static const NCURSES_CH_T blank = NewChar(BLANK_TEXT);
+	SP->_default_color = TRUE;
+	_nc_do_color(-1, 0, FALSE, _nc_outch);
+	SP->_default_color = FALSE;
+
+	mvcur(SP->_cursrow, SP->_curscol, screen_lines - 1, 0);
+
+	ClrToEOL(blank, TRUE);
+    }
+#endif
+    if (SP->_color_defs) {
+	_nc_reset_colors();
+    }
+}
+
+#if USE_XMC_SUPPORT
+NCURSES_EXPORT(void)
+_nc_do_xmc_glitch(attr_t previous)
+{
+    attr_t chg = XMC_CHANGES(previous ^ AttrOf(SCREEN_ATTRS(SP)));
+
+    while (chg != 0) {
+	if (chg & 1) {
+	    SP->_curscol += magic_cookie_glitch;
+	    if (SP->_curscol >= SP->_columns)
+		wrap_cursor();
+	    TR(TRACE_UPDATE, ("bumped to %d,%d after cookie", SP->_cursrow, SP->_curscol));
+	}
+	chg >>= 1;
+    }
+}
+#endif /* USE_XMC_SUPPORT */