winio.c

/* $Id$ */
/**************************************************************************
 *   winio.c                                                              *
 *                                                                        *
 *   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007   *
 *   Free Software Foundation, Inc.                                       *
 *   This program is free software; you can redistribute it and/or modify *
 *   it under the terms of the GNU General Public License as published by *
 *   the Free Software Foundation; either version 3, or (at your option)  *
 *   any later version.                                                   *
 *                                                                        *
 *   This program is distributed in the hope that it will be useful, but  *
 *   WITHOUT ANY WARRANTY; without even the implied warranty of           *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU    *
 *   General Public License for more details.                             *
 *                                                                        *
 *   You should have received a copy of the GNU General Public License    *
 *   along with this program; if not, write to the Free Software          *
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA            *
 *   02110-1301, USA.                                                     *
 *                                                                        *
 **************************************************************************/

#include "proto.h"

#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>

static int *key_buffer = NULL;
	/* The keystroke buffer, containing all the keystrokes we
	 * haven't handled yet at a given point. */
static size_t key_buffer_len = 0;
	/* The length of the keystroke buffer. */
static int statusblank = 0;
	/* The number of keystrokes left after we call statusbar(),
	 * before we actually blank the statusbar. */
static bool disable_cursorpos = FALSE;
	/* Should we temporarily disable constant cursor position
	 * display? */

/* Control character compatibility:
 *
 * - NANO_BACKSPACE_KEY is Ctrl-H, which is Backspace under ASCII, ANSI,
 *   VT100, and VT220.
 * - NANO_TAB_KEY is Ctrl-I, which is Tab under ASCII, ANSI, VT100,
 *   VT220, and VT320.
 * - NANO_ENTER_KEY is Ctrl-M, which is Enter under ASCII, ANSI, VT100,
 *   VT220, and VT320.
 * - NANO_XON_KEY is Ctrl-Q, which is XON under ASCII, ANSI, VT100,
 *   VT220, and VT320.
 * - NANO_XOFF_KEY is Ctrl-S, which is XOFF under ASCII, ANSI, VT100,
 *   VT220, and VT320.
 * - NANO_CONTROL_8 is Ctrl-8 (Ctrl-?), which is Delete under ASCII,
 *   ANSI, VT100, and VT220, and which is Backspace under VT320.
 *
 * Note: VT220 and VT320 also generate Esc [ 3 ~ for Delete.  By
 * default, xterm assumes it's running on a VT320 and generates Ctrl-8
 * (Ctrl-?) for Backspace and Esc [ 3 ~ for Delete.  This causes
 * problems for VT100-derived terminals such as the FreeBSD console,
 * which expect Ctrl-H for Backspace and Ctrl-8 (Ctrl-?) for Delete, and
 * on which the VT320 sequences are translated by the keypad to KEY_DC
 * and [nothing].  We work around this conflict via the REBIND_DELETE
 * flag: if it's not set, we assume VT320 compatibility, and if it is,
 * we assume VT100 compatibility.  Thanks to Lee Nelson and Wouter van
 * Hemel for helping work this conflict out.
 *
 * Escape sequence compatibility:
 *
 * We support escape sequences for ANSI, VT100, VT220, VT320, the Linux
 * console, the FreeBSD console, the Mach console, xterm, rxvt, Eterm,
 * and Terminal.  Among these, there are several conflicts and
 * omissions, outlined as follows:
 *
 * - Tab on ANSI == PageUp on FreeBSD console; the former is omitted.
 *   (Ctrl-I is also Tab on ANSI, which we already support.)
 * - PageDown on FreeBSD console == Center (5) on numeric keypad with
 *   NumLock off on Linux console; the latter is omitted.  (The editing
 *   keypad key is more important to have working than the numeric
 *   keypad key, because the latter has no value when NumLock is off.)
 * - F1 on FreeBSD console == the mouse key on xterm/rxvt/Eterm; the
 *   latter is omitted.  (Mouse input will only work properly if the
 *   extended keypad value KEY_MOUSE is generated on mouse events
 *   instead of the escape sequence.)
 * - F9 on FreeBSD console == PageDown on Mach console; the former is
 *   omitted.  (The editing keypad is more important to have working
 *   than the function keys, because the functions of the former are not
 *   arbitrary and the functions of the latter are.)
 * - F10 on FreeBSD console == PageUp on Mach console; the former is
 *   omitted.  (Same as above.)
 * - F13 on FreeBSD console == End on Mach console; the former is
 *   omitted.  (Same as above.)
 * - F15 on FreeBSD console == Shift-Up on rxvt/Eterm; the former is
 *   omitted.  (The arrow keys, with or without modifiers, are more
 *   important to have working than the function keys, because the
 *   functions of the former are not arbitrary and the functions of the
 *   latter are.)
 * - F16 on FreeBSD console == Shift-Down on rxvt/Eterm; the former is
 *   omitted.  (Same as above.) */

/* Read in a sequence of keystrokes from win and save them in the
 * keystroke buffer.  This should only be called when the keystroke
 * buffer is empty. */
void get_key_buffer(WINDOW *win)
{
    int input;
    size_t errcount;

    /* If the keystroke buffer isn't empty, get out. */
    if (key_buffer != NULL)
	return;

    /* Read in the first character using blocking input. */
#ifndef NANO_TINY
    allow_pending_sigwinch(TRUE);
#endif

    /* Just before reading in the first character, display any pending
     * screen updates. */
    doupdate();

    errcount = 0;
    while ((input = wgetch(win)) == ERR) {
	errcount++;

	/* If we've failed to get a character MAX_BUF_SIZE times in a
	 * row, assume that the input source we were using is gone and
	 * die gracefully.  We could check if errno is set to EIO
	 * ("Input/output error") and die gracefully in that case, but
	 * it's not always set properly.  Argh. */
	if (errcount == MAX_BUF_SIZE)
	    handle_hupterm(0);
    }

#ifndef NANO_TINY
    allow_pending_sigwinch(FALSE);
#endif

    /* Increment the length of the keystroke buffer, and save the value
     * of the keystroke at the end of it. */
    key_buffer_len++;
    key_buffer = (int *)nmalloc(sizeof(int));
    key_buffer[0] = input;

    /* Read in the remaining characters using non-blocking input. */
    nodelay(win, TRUE);

    while (TRUE) {
#ifndef NANO_TINY
	allow_pending_sigwinch(TRUE);
#endif

	input = wgetch(win);

	/* If there aren't any more characters, stop reading. */
	if (input == ERR)
	    break;

	/* Otherwise, increment the length of the keystroke buffer, and
	 * save the value of the keystroke at the end of it. */
	key_buffer_len++;
	key_buffer = (int *)nrealloc(key_buffer, key_buffer_len *
		sizeof(int));
	key_buffer[key_buffer_len - 1] = input;

#ifndef NANO_TINY
	allow_pending_sigwinch(FALSE);
#endif
    }

    /* Switch back to non-blocking input. */
    nodelay(win, FALSE);

#ifdef DEBUG
    fprintf(stderr, "get_key_buffer(): key_buffer_len = %lu\n", (unsigned long)key_buffer_len);
#endif
}

/* Return the length of the keystroke buffer. */
size_t get_key_buffer_len(void)
{
    return key_buffer_len;
}

/* Add the keystrokes in input to the keystroke buffer. */
void unget_input(int *input, size_t input_len)
{
#ifndef NANO_TINY
    allow_pending_sigwinch(TRUE);
    allow_pending_sigwinch(FALSE);
#endif

    /* If input is empty, get out. */
    if (input_len == 0)
	return;

    /* If adding input would put the keystroke buffer beyond maximum
     * capacity, only add enough of input to put it at maximum
     * capacity. */
    if (key_buffer_len + input_len < key_buffer_len)
	input_len = (size_t)-1 - key_buffer_len;

    /* Add the length of input to the length of the keystroke buffer,
     * and reallocate the keystroke buffer so that it has enough room
     * for input. */
    key_buffer_len += input_len;
    key_buffer = (int *)nrealloc(key_buffer, key_buffer_len *
	sizeof(int));

    /* If the keystroke buffer wasn't empty before, move its beginning
     * forward far enough so that we can add input to its beginning. */
    if (key_buffer_len > input_len)
	memmove(key_buffer + input_len, key_buffer,
		(key_buffer_len - input_len) * sizeof(int));

    /* Copy input to the beginning of the keystroke buffer. */
    memcpy(key_buffer, input, input_len * sizeof(int));
}

/* Put back the character stored in kbinput, putting it in byte range
 * beforehand.  If meta_key is TRUE, put back the Escape character after
 * putting back kbinput.  If func_key is TRUE, put back the function key
 * (a value outside byte range) without putting it in byte range. */
void unget_kbinput(int kbinput, bool meta_key, bool func_key)
{
    if (!func_key)
	kbinput = (char)kbinput;

    unget_input(&kbinput, 1);

    if (meta_key) {
	kbinput = NANO_CONTROL_3;
	unget_input(&kbinput, 1);
    }
}

/* Try to read input_len characters from the keystroke buffer.  If the
 * keystroke buffer is empty and win isn't NULL, try to read in more
 * characters from win and add them to the keystroke buffer before doing
 * anything else.  If the keystroke buffer is empty and win is NULL,
 * return NULL. */
int *get_input(WINDOW *win, size_t input_len)
{
    int *input;

#ifndef NANO_TINY
    allow_pending_sigwinch(TRUE);
    allow_pending_sigwinch(FALSE);
#endif

    if (key_buffer_len == 0) {
	if (win != NULL) {
	    get_key_buffer(win);

	    if (key_buffer_len == 0)
		return NULL;
	} else
	    return NULL;
    }

    /* If input_len is greater than the length of the keystroke buffer,
     * only read the number of characters in the keystroke buffer. */
    if (input_len > key_buffer_len)
	input_len = key_buffer_len;

    /* Subtract input_len from the length of the keystroke buffer, and
     * allocate input so that it has enough room for input_len
     * keystrokes. */
    key_buffer_len -= input_len;
    input = (int *)nmalloc(input_len * sizeof(int));

    /* Copy input_len keystrokes from the beginning of the keystroke
     * buffer into input. */
    memcpy(input, key_buffer, input_len * sizeof(int));

    /* If the keystroke buffer is empty, mark it as such. */
    if (key_buffer_len == 0) {
	free(key_buffer);
	key_buffer = NULL;
    /* If the keystroke buffer isn't empty, move its beginning forward
     * far enough so that the keystrokes in input are no longer at its
     * beginning. */
    } else {
	memmove(key_buffer, key_buffer + input_len, key_buffer_len *
		sizeof(int));
	key_buffer = (int *)nrealloc(key_buffer, key_buffer_len *
		sizeof(int));
    }

    return input;
}

/* Read in a single character.  If it's ignored, swallow it and go on.
 * Otherwise, try to translate it from ASCII, meta key sequences, escape
 * sequences, and/or extended keypad values.  Set meta_key to TRUE when
 * we get a meta key sequence, and set func_key to TRUE when we get an
 * extended keypad value.  Supported extended keypad values consist of
 * [arrow key], Ctrl-[arrow key], Shift-[arrow key], Enter, Backspace,
 * the editing keypad (Insert, Delete, Home, End, PageUp, and PageDown),
 * the function keypad (F1-F16), and the numeric keypad with NumLock
 * off.  Assume nodelay(win) is FALSE. */
int get_kbinput(WINDOW *win, bool *meta_key, bool *func_key)
{
    int kbinput;

    /* Read in a character and interpret it.  Continue doing this until
     * we get a recognized value or sequence. */
    while ((kbinput = parse_kbinput(win, meta_key, func_key)) == ERR);

    /* If we read from the edit window, blank the statusbar if we need
     * to. */
    if (win == edit)
	check_statusblank();

    return kbinput;
}

/* Translate ASCII characters, extended keypad values, and escape
 * sequences into their corresponding key values.  Set meta_key to TRUE
 * when we get a meta key sequence, and set func_key to TRUE when we get
 * a function key.  Assume nodelay(win) is FALSE. */
int parse_kbinput(WINDOW *win, bool *meta_key, bool *func_key)
{
    static int escapes = 0, byte_digits = 0;
    int *kbinput, retval = ERR;

    *meta_key = FALSE;
    *func_key = FALSE;

    /* Read in a character. */
    while ((kbinput = get_input(win, 1)) == NULL);

    switch (*kbinput) {
	case ERR:
	    break;
	case NANO_CONTROL_3:
	    /* Increment the escape counter. */
	    escapes++;
	    switch (escapes) {
		case 1:
		    /* One escape: wait for more input. */
		case 2:
		    /* Two escapes: wait for more input. */
		case 3:
		    /* Three escapes: wait for more input. */
		    break;
		default:
		    /* More than three escapes: limit the escape counter
		     * to no more than two, and wait for more input. */
		    escapes %= 3;
	    }
	    break;
	default:
	    switch (escapes) {
		case 0:
		    /* One non-escape: normal input mode.  Save the
		     * non-escape character as the result. */
		    retval = *kbinput;
		    break;
		case 1:
		    /* Reset the escape counter. */
		    escapes = 0;
		    if (get_key_buffer_len() == 0) {
			/* One escape followed by a non-escape, and
			 * there aren't any other keystrokes waiting:
			 * meta key sequence mode.  Set meta_key to
			 * TRUE, and save the lowercase version of the
			 * non-escape character as the result. */
			*meta_key = TRUE;
			retval = tolower(*kbinput);
		    } else
			/* One escape followed by a non-escape, and
			 * there are other keystrokes waiting: escape
			 * sequence mode.  Interpret the escape
			 * sequence. */
			retval = parse_escape_seq_kbinput(win,
				*kbinput);
		    break;
		case 2:
		    if (get_key_buffer_len() == 0) {
			if (('0' <= *kbinput && *kbinput <= '2' &&
				byte_digits == 0) || ('0' <= *kbinput &&
				*kbinput <= '9' && byte_digits > 0)) {
			    /* Two escapes followed by one or more
			     * decimal digits, and there aren't any
			     * other keystrokes waiting: byte sequence
			     * mode.  If the byte sequence's range is
			     * limited to 2XX (the first digit is in the
			     * '0' to '2' range and it's the first
			     * digit, or it's in the '0' to '9' range
			     * and it's not the first digit), increment
			     * the byte sequence counter and interpret
			     * the digit.  If the byte sequence's range
			     * is not limited to 2XX, fall through. */
			    int byte;

			    byte_digits++;
			    byte = get_byte_kbinput(*kbinput);

			    if (byte != ERR) {
				char *byte_mb;
				int byte_mb_len, *seq, i;

				/* If we've read in a complete byte
				 * sequence, reset the escape counter
				 * and the byte sequence counter, and
				 * put back the corresponding byte
				 * value. */
				escapes = 0;
				byte_digits = 0;

				/* Put back the multibyte equivalent of
				 * the byte value. */
				byte_mb = make_mbchar((long)byte,
					&byte_mb_len);

				seq = (int *)nmalloc(byte_mb_len *
					sizeof(int));

				for (i = 0; i < byte_mb_len; i++)
				    seq[i] = (unsigned char)byte_mb[i];

				unget_input(seq, byte_mb_len);

				free(byte_mb);
				free(seq);
			    }
			} else {
			    /* Reset the escape counter. */
			    escapes = 0;
			    if (byte_digits == 0)
				/* Two escapes followed by a non-decimal
				 * digit or a decimal digit that would
				 * create a byte sequence greater than
				 * 2XX, we're not in the middle of a
				 * byte sequence, and there aren't any
				 * other keystrokes waiting: control
				 * character sequence mode.  Interpret
				 * the control sequence and save the
				 * corresponding control character as
				 * the result. */
				retval = get_control_kbinput(*kbinput);
			    else {
				/* If we're in the middle of a byte
				 * sequence, reset the byte sequence
				 * counter and save the character we got
				 * as the result. */
				byte_digits = 0;
				retval = *kbinput;
			    }
			}
		    } else {
			/* Two escapes followed by a non-escape, and
			 * there are other keystrokes waiting: combined
			 * meta and escape sequence mode.  Reset the
			 * escape counter, set meta_key to TRUE, and
			 * interpret the escape sequence. */
			escapes = 0;
			*meta_key = TRUE;
			retval = parse_escape_seq_kbinput(win,
				*kbinput);
		    }
		    break;
		case 3:
		    /* Reset the escape counter. */
		    escapes = 0;
		    if (get_key_buffer_len() == 0)
			/* Three escapes followed by a non-escape, and
			 * there aren't any other keystrokes waiting:
			 * normal input mode.  Save the non-escape
			 * character as the result. */
			retval = *kbinput;
		    else
			/* Three escapes followed by a non-escape, and
			 * there are other keystrokes waiting: combined
			 * control character and escape sequence mode.
			 * Interpret the escape sequence, and interpret
			 * the result as a control sequence. */
			retval = get_control_kbinput(
				parse_escape_seq_kbinput(win,
				*kbinput));
		    break;
	    }
    }

    if (retval != ERR) {
	switch (retval) {
	    case NANO_CONTROL_8:
		retval = ISSET(REBIND_DELETE) ? NANO_DELETE_KEY :
			NANO_BACKSPACE_KEY;
		break;
	    case KEY_DOWN:
		retval = NANO_NEXTLINE_KEY;
		break;
	    case KEY_UP:
		retval = NANO_PREVLINE_KEY;
		break;
	    case KEY_LEFT:
		retval = NANO_BACK_KEY;
		break;
	    case KEY_RIGHT:
		retval = NANO_FORWARD_KEY;
		break;
#ifdef KEY_HOME
	    /* HP-UX 10-11 doesn't support KEY_HOME. */
	    case KEY_HOME:
		retval = NANO_HOME_KEY;
		break;
#endif
	    case KEY_BACKSPACE:
		retval = NANO_BACKSPACE_KEY;
		break;
	    case KEY_DC:
		retval = ISSET(REBIND_DELETE) ? NANO_BACKSPACE_KEY :
			NANO_DELETE_KEY;
		break;
	    case KEY_IC:
		retval = NANO_INSERTFILE_KEY;
		break;
	    case KEY_NPAGE:
		retval = NANO_NEXTPAGE_KEY;
		break;
	    case KEY_PPAGE:
		retval = NANO_PREVPAGE_KEY;
		break;
	    case KEY_ENTER:
		retval = NANO_ENTER_KEY;
		break;
	    case KEY_A1:	/* Home (7) on numeric keypad with
				 * NumLock off. */
		retval = NANO_HOME_KEY;
		break;
	    case KEY_A3:	/* PageUp (9) on numeric keypad with
				 * NumLock off. */
		retval = NANO_PREVPAGE_KEY;
		break;
	    case KEY_B2:	/* Center (5) on numeric keypad with
				 * NumLock off. */
		retval = ERR;
		break;
	    case KEY_C1:	/* End (1) on numeric keypad with
				 * NumLock off. */
		retval = NANO_END_KEY;
		break;
	    case KEY_C3:	/* PageDown (4) on numeric keypad with
				 * NumLock off. */
		retval = NANO_NEXTPAGE_KEY;
		break;
#ifdef KEY_BEG
	    /* Slang doesn't support KEY_BEG. */
	    case KEY_BEG:	/* Center (5) on numeric keypad with
				 * NumLock off. */
		retval = ERR;
		break;
#endif
#ifdef KEY_CANCEL
	    /* Slang doesn't support KEY_CANCEL. */
	    case KEY_CANCEL:
		retval = NANO_CANCEL_KEY;
		break;
#endif
#ifdef KEY_END
	    /* HP-UX 10-11 doesn't support KEY_END. */
	    case KEY_END:
		retval = NANO_END_KEY;
		break;
#endif
#ifdef KEY_SBEG
	    /* Slang doesn't support KEY_SBEG. */
	    case KEY_SBEG:	/* Center (5) on numeric keypad with
				 * NumLock off. */
		retval = ERR;
		break;
#endif
#ifdef KEY_SCANCEL
	    /* Slang doesn't support KEY_SCANCEL. */
	    case KEY_SCANCEL:
		retval = NANO_CANCEL_KEY;
		break;
#endif
#ifdef KEY_SDC
	    /* Slang doesn't support KEY_SDC. */
	    case KEY_SDC:
		retval = ISSET(REBIND_DELETE) ? NANO_BACKSPACE_KEY :
			NANO_DELETE_KEY;
		break;
#endif
#ifdef KEY_SEND
	    /* HP-UX 10-11 and Slang don't support KEY_SEND. */
	    case KEY_SEND:
		retval = NANO_END_KEY;
		break;
#endif
#ifdef KEY_SHOME
	    /* HP-UX 10-11 and Slang don't support KEY_SHOME. */
	    case KEY_SHOME:
		retval = NANO_HOME_KEY;
		break;
#endif
#ifdef KEY_SIC
	    /* Slang doesn't support KEY_SIC. */
	    case KEY_SIC:
		retval = NANO_INSERTFILE_KEY;
		break;
#endif
#ifdef KEY_SDOWN
	    /* ncurses and Slang don't support KEY_SDOWN. */
	    case KEY_SDOWN:
		retval = NANO_NEXTLINE_KEY;
		break;
#endif
#ifdef KEY_SUP
	    /* ncurses and Slang don't support KEY_SUP. */
	    case KEY_SUP:
		retval = NANO_PREVLINE_KEY;
		break;
#endif
#ifdef KEY_SLEFT
	    /* Slang doesn't support KEY_SLEFT. */
	    case KEY_SLEFT:
		retval = NANO_BACK_KEY;
		break;
#endif
#ifdef KEY_SRIGHT
	    /* Slang doesn't support KEY_SRIGHT. */
	    case KEY_SRIGHT:
		retval = NANO_FORWARD_KEY;
		break;
#endif
#ifdef KEY_SSUSPEND
	    /* Slang doesn't support KEY_SSUSPEND. */
	    case KEY_SSUSPEND:
		retval = NANO_SUSPEND_KEY;
		break;
#endif
#ifdef KEY_SUSPEND
	    /* Slang doesn't support KEY_SUSPEND. */
	    case KEY_SUSPEND:
		retval = NANO_SUSPEND_KEY;
		break;
#endif
#ifdef PDCURSES
	    case KEY_SHIFT_L:
	    case KEY_SHIFT_R:
	    case KEY_CONTROL_L:
	    case KEY_CONTROL_R:
	    case KEY_ALT_L:
	    case KEY_ALT_R:
		retval = ERR;
		break;
#endif
#if !defined(NANO_TINY) && defined(KEY_RESIZE)
	    /* Since we don't change the default SIGWINCH handler when
	     * NANO_TINY is defined, KEY_RESIZE is never generated.
	     * Also, Slang and SunOS 5.7-5.9 don't support
	     * KEY_RESIZE. */
	    case KEY_RESIZE:
		retval = ERR;
		break;
#endif
	}

	/* If our result is an extended keypad value (i.e. a value
	 * outside of byte range), set func_key to TRUE. */
	if (retval != ERR)
	    *func_key = !is_byte(retval);
    }

#ifdef DEBUG
    fprintf(stderr, "parse_kbinput(): kbinput = %d, meta_key = %s, func_key = %s, escapes = %d, byte_digits = %d, retval = %d\n", *kbinput, *meta_key ? "TRUE" : "FALSE", *func_key ? "TRUE" : "FALSE", escapes, byte_digits, retval);
#endif

    free(kbinput);

    /* Return the result. */
    return retval;
}

/* Translate escape sequences, most of which correspond to extended
 * keypad values, into their corresponding key values.  These sequences
 * are generated when the keypad doesn't support the needed keys.
 * Assume that Escape has already been read in. */
int get_escape_seq_kbinput(const int *seq, size_t seq_len)
{
    int retval = ERR;

    if (seq_len > 1) {
	switch (seq[0]) {
	    case 'O':
		switch (seq[1]) {
		    case '1':
			if (seq_len >= 3) {
			    switch (seq[2]) {
				case ';':
    if (seq_len >= 4) {
	switch (seq[3]) {
	    case '2':
		if (seq_len >= 5) {
		    switch (seq[4]) {
			case 'A': /* Esc O 1 ; 2 A == Shift-Up on
				   * Terminal. */
			case 'B': /* Esc O 1 ; 2 B == Shift-Down on
				   * Terminal. */
			case 'C': /* Esc O 1 ; 2 C == Shift-Right on
				   * Terminal. */
			case 'D': /* Esc O 1 ; 2 D == Shift-Left on
				   * Terminal. */
			    retval = get_escape_seq_abcd(seq[4]);
			    break;
			case 'P': /* Esc O 1 ; 2 P == F13 on
				   * Terminal. */
			    retval = KEY_F(13);
			    break;
			case 'Q': /* Esc O 1 ; 2 Q == F14 on
				   * Terminal. */
			    retval = KEY_F(14);
			    break;
			case 'R': /* Esc O 1 ; 2 R == F15 on
				   * Terminal. */
			    retval = KEY_F(15);
			    break;
			case 'S': /* Esc O 1 ; 2 S == F16 on
				   * Terminal. */
			    retval = KEY_F(16);
			    break;
		    }
		}
		break;
	    case '5':
		if (seq_len >= 5) {
		    switch (seq[4]) {
			case 'A': /* Esc O 1 ; 5 A == Ctrl-Up on
				   * Terminal. */
			case 'B': /* Esc O 1 ; 5 B == Ctrl-Down on
				   * Terminal. */
			case 'C': /* Esc O 1 ; 5 C == Ctrl-Right on
				   * Terminal. */
			case 'D': /* Esc O 1 ; 5 D == Ctrl-Left on
				   * Terminal. */
			    retval = get_escape_seq_abcd(seq[4]);
			    break;
		    }
		}
		break;
	}
    }
				    break;
			    }
			}
			break;
		    case '2':
			if (seq_len >= 3) {
			    switch (seq[2]) {
				case 'P': /* Esc O 2 P == F13 on
					   * xterm. */
				    retval = KEY_F(13);
				    break;
				case 'Q': /* Esc O 2 Q == F14 on
					   * xterm. */
				    retval = KEY_F(14);
				    break;
				case 'R': /* Esc O 2 R == F15 on
					   * xterm. */
				    retval = KEY_F(15);
				    break;
				case 'S': /* Esc O 2 S == F16 on
					   * xterm. */
				    retval = KEY_F(16);
				    break;
			    }
			}
			break;
		    case 'A': /* Esc O A == Up on VT100/VT320/xterm. */
		    case 'B': /* Esc O B == Down on
			       * VT100/VT320/xterm. */
		    case 'C': /* Esc O C == Right on
			       * VT100/VT320/xterm. */
		    case 'D': /* Esc O D == Left on
			       * VT100/VT320/xterm. */
			retval = get_escape_seq_abcd(seq[1]);
			break;
		    case 'E': /* Esc O E == Center (5) on numeric keypad
			       * with NumLock off on xterm. */
			retval = KEY_B2;
			break;
		    case 'F': /* Esc O F == End on xterm/Terminal. */
			retval = NANO_END_KEY;
			break;
		    case 'H': /* Esc O H == Home on xterm/Terminal. */
			retval = NANO_HOME_KEY;
			break;
		    case 'M': /* Esc O M == Enter on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt/Eterm. */
			retval = NANO_ENTER_KEY;
			break;
		    case 'P': /* Esc O P == F1 on VT100/VT220/VT320/Mach
			       * console. */
			retval = KEY_F(1);
			break;
		    case 'Q': /* Esc O Q == F2 on VT100/VT220/VT320/Mach
			       * console. */
			retval = KEY_F(2);
			break;
		    case 'R': /* Esc O R == F3 on VT100/VT220/VT320/Mach
			       * console. */
			retval = KEY_F(3);
			break;
		    case 'S': /* Esc O S == F4 on VT100/VT220/VT320/Mach
			       * console. */
			retval = KEY_F(4);
			break;
		    case 'T': /* Esc O T == F5 on Mach console. */
			retval = KEY_F(5);
			break;
		    case 'U': /* Esc O U == F6 on Mach console. */
			retval = KEY_F(6);
			break;
		    case 'V': /* Esc O V == F7 on Mach console. */
			retval = KEY_F(7);
			break;
		    case 'W': /* Esc O W == F8 on Mach console. */
			retval = KEY_F(8);
			break;
		    case 'X': /* Esc O X == F9 on Mach console. */
			retval = KEY_F(9);
			break;
		    case 'Y': /* Esc O Y == F10 on Mach console. */
			retval = KEY_F(10);
			break;
		    case 'a': /* Esc O a == Ctrl-Up on rxvt. */
		    case 'b': /* Esc O b == Ctrl-Down on rxvt. */
		    case 'c': /* Esc O c == Ctrl-Right on rxvt. */
		    case 'd': /* Esc O d == Ctrl-Left on rxvt. */
			retval = get_escape_seq_abcd(seq[1]);
			break;
		    case 'j': /* Esc O j == '*' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt/Eterm/Terminal. */
			retval = '*';
			break;
		    case 'k': /* Esc O k == '+' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt/Eterm/Terminal. */
			retval = '+';
			break;
		    case 'l': /* Esc O l == ',' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt/Eterm/Terminal. */
			retval = ',';
			break;
		    case 'm': /* Esc O m == '-' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt/Eterm/Terminal. */
			retval = '-';
			break;
		    case 'n': /* Esc O n == Delete (.) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * xterm/rxvt/Eterm/Terminal. */
			retval = NANO_DELETE_KEY;
			break;
		    case 'o': /* Esc O o == '/' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt/Eterm/Terminal. */
			retval = '/';
			break;
		    case 'p': /* Esc O p == Insert (0) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_INSERTFILE_KEY;
			break;
		    case 'q': /* Esc O q == End (1) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_END_KEY;
			break;
		    case 'r': /* Esc O r == Down (2) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_NEXTLINE_KEY;
			break;
		    case 's': /* Esc O s == PageDown (3) on numeric
			       * keypad with NumLock off on VT100/VT220/
			       * VT320/rxvt/Eterm/Terminal. */
			retval = NANO_NEXTPAGE_KEY;
			break;
		    case 't': /* Esc O t == Left (4) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_BACK_KEY;
			break;
		    case 'u': /* Esc O u == Center (5) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm. */
			retval = KEY_B2;
			break;
		    case 'v': /* Esc O v == Right (6) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_FORWARD_KEY;
			break;
		    case 'w': /* Esc O w == Home (7) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_HOME_KEY;
			break;
		    case 'x': /* Esc O x == Up (8) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_PREVLINE_KEY;
			break;
		    case 'y': /* Esc O y == PageUp (9) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm/Terminal. */
			retval = NANO_PREVPAGE_KEY;
			break;
		}
		break;
	    case 'o':
		switch (seq[1]) {
		    case 'a': /* Esc o a == Ctrl-Up on Eterm. */
		    case 'b': /* Esc o b == Ctrl-Down on Eterm. */
		    case 'c': /* Esc o c == Ctrl-Right on Eterm. */
		    case 'd': /* Esc o d == Ctrl-Left on Eterm. */
			retval = get_escape_seq_abcd(seq[1]);
			break;
		}
		break;
	    case '[':
		switch (seq[1]) {
		    case '1':
			if (seq_len >= 3) {
			    switch (seq[2]) {
				case '1': /* Esc [ 1 1 ~ == F1 on rxvt/
					   * Eterm. */
				    retval = KEY_F(1);
				    break;
				case '2': /* Esc [ 1 2 ~ == F2 on rxvt/
					   * Eterm. */
				    retval = KEY_F(2);
				    break;
				case '3': /* Esc [ 1 3 ~ == F3 on rxvt/
					   * Eterm. */
				    retval = KEY_F(3);
				    break;
				case '4': /* Esc [ 1 4 ~ == F4 on rxvt/
					   * Eterm. */
				    retval = KEY_F(4);
				    break;
				case '5': /* Esc [ 1 5 ~ == F5 on xterm/
					   * rxvt/Eterm. */
				    retval = KEY_F(5);
				    break;
				case '7': /* Esc [ 1 7 ~ == F6 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(6);
				    break;
				case '8': /* Esc [ 1 8 ~ == F7 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(7);
				    break;
				case '9': /* Esc [ 1 9 ~ == F8 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(8);
				    break;
				case ';':
    if (seq_len >= 4) {
	switch (seq[3]) {
	    case '2':
		if (seq_len >= 5) {
		    switch (seq[4]) {
			case 'A': /* Esc [ 1 ; 2 A == Shift-Up on
				   * xterm. */
			case 'B': /* Esc [ 1 ; 2 B == Shift-Down on
				   * xterm. */
			case 'C': /* Esc [ 1 ; 2 C == Shift-Right on
				   * xterm. */
			case 'D': /* Esc [ 1 ; 2 D == Shift-Left on
				   * xterm. */
			    retval = get_escape_seq_abcd(seq[4]);
			    break;
		    }
		}
		break;
	    case '5':
		if (seq_len >= 5) {
		    switch (seq[4]) {
			case 'A': /* Esc [ 1 ; 5 A == Ctrl-Up on
				   * xterm. */
			case 'B': /* Esc [ 1 ; 5 B == Ctrl-Down on
				   * xterm. */
			case 'C': /* Esc [ 1 ; 5 C == Ctrl-Right on
				   * xterm. */
			case 'D': /* Esc [ 1 ; 5 D == Ctrl-Left on
				   * xterm. */
			    retval = get_escape_seq_abcd(seq[4]);
			    break;
		    }
		}
		break;
	}
    }
				    break;
				default: /* Esc [ 1 ~ == Home on
					  * VT320/Linux console. */
				    retval = NANO_HOME_KEY;
				    break;
			    }
			}
			break;
		    case '2':
			if (seq_len >= 3) {
			    switch (seq[2]) {
				case '0': /* Esc [ 2 0 ~ == F9 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(9);
				    break;
				case '1': /* Esc [ 2 1 ~ == F10 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(10);
				    break;
				case '3': /* Esc [ 2 3 ~ == F11 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(11);
				    break;
				case '4': /* Esc [ 2 4 ~ == F12 on
					   * VT220/VT320/Linux console/
					   * xterm/rxvt/Eterm. */
				    retval = KEY_F(12);
				    break;
				case '5': /* Esc [ 2 5 ~ == F13 on
					   * VT220/VT320/Linux console/
					   * rxvt/Eterm. */
				    retval = KEY_F(13);
				    break;
				case '6': /* Esc [ 2 6 ~ == F14 on
					   * VT220/VT320/Linux console/
					   * rxvt/Eterm. */
				    retval = KEY_F(14);
				    break;
				case '8': /* Esc [ 2 8 ~ == F15 on
					   * VT220/VT320/Linux console/
					   * rxvt/Eterm. */
				    retval = KEY_F(15);
				    break;
				case '9': /* Esc [ 2 9 ~ == F16 on
					   * VT220/VT320/Linux console/
					   * rxvt/Eterm. */
				    retval = KEY_F(16);
				    break;
				default: /* Esc [ 2 ~ == Insert on
					  * VT220/VT320/Linux console/
					  * xterm/Terminal. */
				    retval = NANO_INSERTFILE_KEY;
				    break;
			    }
			}
			break;
		    case '3': /* Esc [ 3 ~ == Delete on VT220/VT320/
			       * Linux console/xterm/Terminal. */
			retval = NANO_DELETE_KEY;
			break;
		    case '4': /* Esc [ 4 ~ == End on VT220/VT320/Linux
			       * console/xterm. */
			retval = NANO_END_KEY;
			break;
		    case '5': /* Esc [ 5 ~ == PageUp on VT220/VT320/
			       * Linux console/xterm/Terminal;
			       * Esc [ 5 ^ == PageUp on Eterm. */
			retval = NANO_PREVPAGE_KEY;
			break;
		    case '6': /* Esc [ 6 ~ == PageDown on VT220/VT320/
			       * Linux console/xterm/Terminal;
			        * Esc [ 6 ^ == PageDown on Eterm. */
			retval = NANO_NEXTPAGE_KEY;
			break;
		    case '7': /* Esc [ 7 ~ == Home on rxvt. */
			retval = NANO_HOME_KEY;
			break;
		    case '8': /* Esc [ 8 ~ == End on rxvt. */
			retval = NANO_END_KEY;
			break;
		    case '9': /* Esc [ 9 == Delete on Mach console. */
			retval = NANO_DELETE_KEY;
			break;
		    case '@': /* Esc [ @ == Insert on Mach console. */
			retval = NANO_INSERTFILE_KEY;
			break;
		    case 'A': /* Esc [ A == Up on ANSI/VT220/Linux
			       * console/FreeBSD console/Mach console/
			       * rxvt/Eterm/Terminal. */
		    case 'B': /* Esc [ B == Down on ANSI/VT220/Linux
			       * console/FreeBSD console/Mach console/
			       * rxvt/Eterm/Terminal. */
		    case 'C': /* Esc [ C == Right on ANSI/VT220/Linux
			       * console/FreeBSD console/Mach console/
			       * rxvt/Eterm/Terminal. */
		    case 'D': /* Esc [ D == Left on ANSI/VT220/Linux
			       * console/FreeBSD console/Mach console/
			       * rxvt/Eterm/Terminal. */
			retval = get_escape_seq_abcd(seq[1]);
			break;
		    case 'E': /* Esc [ E == Center (5) on numeric keypad
			       * with NumLock off on FreeBSD console/
			       * Terminal. */
			retval = KEY_B2;
			break;
		    case 'F': /* Esc [ F == End on FreeBSD
			       * console/Eterm. */
			retval = NANO_END_KEY;
			break;
		    case 'G': /* Esc [ G == PageDown on FreeBSD
			       * console. */
			retval = NANO_NEXTPAGE_KEY;
			break;
		    case 'H': /* Esc [ H == Home on ANSI/VT220/FreeBSD
			       * console/Mach console/Eterm. */
			retval = NANO_HOME_KEY;
			break;
		    case 'I': /* Esc [ I == PageUp on FreeBSD
			       * console. */
			retval = NANO_PREVPAGE_KEY;
			break;
		    case 'L': /* Esc [ L == Insert on ANSI/FreeBSD
			       * console. */
			retval = NANO_INSERTFILE_KEY;
			break;
		    case 'M': /* Esc [ M == F1 on FreeBSD console. */
			retval = KEY_F(1);
			break;
		    case 'N': /* Esc [ N == F2 on FreeBSD console. */
			retval = KEY_F(2);
			break;
		    case 'O':
			if (seq_len >= 3) {
			    switch (seq[2]) {
				case 'P': /* Esc [ O P == F1 on
					   * xterm. */
				    retval = KEY_F(1);
				    break;
				case 'Q': /* Esc [ O Q == F2 on
					   * xterm. */
				    retval = KEY_F(2);
				    break;
				case 'R': /* Esc [ O R == F3 on
					   * xterm. */
				    retval = KEY_F(3);
				    break;
				case 'S': /* Esc [ O S == F4 on
					   * xterm. */
				    retval = KEY_F(4);
				    break;
			    }
			} else
			    /* Esc [ O == F3 on FreeBSD console. */
			    retval = KEY_F(3);
			break;
		    case 'P': /* Esc [ P == F4 on FreeBSD console. */
			retval = KEY_F(4);
			break;
		    case 'Q': /* Esc [ Q == F5 on FreeBSD console. */
			retval = KEY_F(5);
			break;
		    case 'R': /* Esc [ R == F6 on FreeBSD console. */
			retval = KEY_F(6);
			break;
		    case 'S': /* Esc [ S == F7 on FreeBSD console. */
			retval = KEY_F(7);
			break;
		    case 'T': /* Esc [ T == F8 on FreeBSD console. */
			retval = KEY_F(8);
			break;
		    case 'U': /* Esc [ U == PageDown on Mach console. */
			retval = NANO_NEXTPAGE_KEY;
			break;
		    case 'V': /* Esc [ V == PageUp on Mach console. */
			retval = NANO_PREVPAGE_KEY;
			break;
		    case 'W': /* Esc [ W == F11 on FreeBSD console. */
			retval = KEY_F(11);
			break;
		    case 'X': /* Esc [ X == F12 on FreeBSD console. */
			retval = KEY_F(12);
			break;
		    case 'Y': /* Esc [ Y == End on Mach console. */
			retval = NANO_END_KEY;
			break;
		    case 'Z': /* Esc [ Z == F14 on FreeBSD console. */
			retval = KEY_F(14);
			break;
		    case 'a': /* Esc [ a == Shift-Up on rxvt/Eterm. */
		    case 'b': /* Esc [ b == Shift-Down on rxvt/Eterm. */
		    case 'c': /* Esc [ c == Shift-Right on rxvt/
			       * Eterm. */
		    case 'd': /* Esc [ d == Shift-Left on rxvt/Eterm. */
			retval = get_escape_seq_abcd(seq[1]);
			break;
		    case '[':
			if (seq_len >= 3) {
			    switch (seq[2]) {
				case 'A': /* Esc [ [ A == F1 on Linux
					   * console. */
				    retval = KEY_F(1);
				    break;
				case 'B': /* Esc [ [ B == F2 on Linux
					   * console. */
				    retval = KEY_F(2);
				    break;
				case 'C': /* Esc [ [ C == F3 on Linux
					   * console. */
				    retval = KEY_F(3);
				    break;
				case 'D': /* Esc [ [ D == F4 on Linux
					   * console. */
				    retval = KEY_F(4);
				    break;
				case 'E': /* Esc [ [ E == F5 on Linux
					   * console. */
				    retval = KEY_F(5);
				    break;
			    }
			}
			break;
		}
		break;
	}
    }

#ifdef DEBUG
    fprintf(stderr, "get_escape_seq_kbinput(): retval = %d\n", retval);
#endif

    return retval;
}

/* Return the equivalent arrow key value for the case-insensitive
 * letters A (up), B (down), C (right), and D (left).  These are common
 * to many escape sequences. */
int get_escape_seq_abcd(int kbinput)
{
    switch (tolower(kbinput)) {
	case 'a':
	    return NANO_PREVLINE_KEY;
	case 'b':
	    return NANO_NEXTLINE_KEY;
	case 'c':
	    return NANO_FORWARD_KEY;
	case 'd':
	    return NANO_BACK_KEY;
	default:
	    return ERR;
    }
}

/* Interpret the escape sequence in the keystroke buffer, the first
 * character of which is kbinput.  Assume that the keystroke buffer
 * isn't empty, and that the initial escape has already been read in. */
int parse_escape_seq_kbinput(WINDOW *win, int kbinput)
{
    int retval, *seq;
    size_t seq_len;

    /* Put back the non-escape character, get the complete escape
     * sequence, translate the sequence into its corresponding key
     * value, and save that as the result. */
    unget_input(&kbinput, 1);
    seq_len = get_key_buffer_len();
    seq = get_input(NULL, seq_len);
    retval = get_escape_seq_kbinput(seq, seq_len);

    free(seq);

    /* If we got an unrecognized escape sequence, throw it out. */
    if (retval == ERR) {
	if (win == edit) {
	    statusbar(_("Unknown Command"));
	    beep();
	}
    }

#ifdef DEBUG
    fprintf(stderr, "parse_escape_seq_kbinput(): kbinput = %d, seq_len = %lu, retval = %d\n", kbinput, (unsigned long)seq_len, retval);
#endif

    return retval;
}

/* Translate a byte sequence: turn a three-digit decimal number (from
 * 000 to 255) into its corresponding byte value. */
int get_byte_kbinput(int kbinput)
{
    static int byte_digits = 0, byte = 0;
    int retval = ERR;

    /* Increment the byte digit counter. */
    byte_digits++;

    switch (byte_digits) {
	case 1:
	    /* First digit: This must be from zero to two.  Put it in
	     * the 100's position of the byte sequence holder. */
	    if ('0' <= kbinput && kbinput <= '2')
		byte = (kbinput - '0') * 100;
	    else
		/* This isn't the start of a byte sequence.  Return this
		 * character as the result. */
		retval = kbinput;
	    break;
	case 2:
	    /* Second digit: This must be from zero to five if the first
	     * was two, and may be any decimal value if the first was
	     * zero or one.  Put it in the 10's position of the byte
	     * sequence holder. */
	    if (('0' <= kbinput && kbinput <= '5') || (byte < 200 &&
		'6' <= kbinput && kbinput <= '9'))
		byte += (kbinput - '0') * 10;
	    else
		/* This isn't the second digit of a byte sequence.
		 * Return this character as the result. */
		retval = kbinput;
	    break;
	case 3:
	    /* Third digit: This must be from zero to five if the first
	     * was two and the second was between zero and five, and may
	     * be any decimal value if the first was zero or one and the
	     * second was between six and nine.  Put it in the 1's
	     * position of the byte sequence holder. */
	    if (('0' <= kbinput && kbinput <= '5') || (byte < 250 &&
		'6' <= kbinput && kbinput <= '9')) {
		byte += kbinput - '0';
		/* If this character is a valid decimal value, then the
		 * byte sequence is complete. */
		retval = byte;
	    } else
		/* This isn't the third digit of a byte sequence.
		 * Return this character as the result. */
		retval = kbinput;
	    break;
	default:
	    /* If there are more than three digits, return this
	     * character as the result.  (Maybe we should produce an
	     * error instead?) */
	    retval = kbinput;
	    break;
    }

    /* If we have a result, reset the byte digit counter and the byte
     * sequence holder. */
    if (retval != ERR) {
	byte_digits = 0;
	byte = 0;
    }

#ifdef DEBUG
    fprintf(stderr, "get_byte_kbinput(): kbinput = %d, byte_digits = %d, byte = %d, retval = %d\n", kbinput, byte_digits, byte, retval);
#endif

    return retval;
}

#ifdef ENABLE_UTF8
/* If the character in kbinput is a valid hexadecimal digit, multiply it
 * by factor and add the result to uni. */
long add_unicode_digit(int kbinput, long factor, long *uni)
{
    long retval = ERR;

    if ('0' <= kbinput && kbinput <= '9')
	*uni += (kbinput - '0') * factor;
    else if ('a' <= tolower(kbinput) && tolower(kbinput) <= 'f')
	*uni += (tolower(kbinput) - 'a' + 10) * factor;
    else
	/* If this character isn't a valid hexadecimal value, save it as
	 * the result. */
	retval = kbinput;

    return retval;
}

/* Translate a Unicode sequence: turn a six-digit hexadecimal number
 * (from 000000 to 10FFFF, case-insensitive) into its corresponding
 * multibyte value. */
long get_unicode_kbinput(int kbinput)
{
    static int uni_digits = 0;
    static long uni = 0;
    long retval = ERR;

    /* Increment the Unicode digit counter. */
    uni_digits++;

    switch (uni_digits) {
	case 1:
	    /* First digit: This must be zero or one.  Put it in the
	     * 0x100000's position of the Unicode sequence holder. */
	    if ('0' <= kbinput && kbinput <= '1')
		uni = (kbinput - '0') * 0x100000;
	    else
		/* This isn't the first digit of a Unicode sequence.
		 * Return this character as the result. */
		retval = kbinput;
	    break;
	case 2:
	    /* Second digit: This must be zero if the first was one, and
	     * may be any hexadecimal value if the first was zero.  Put
	     * it in the 0x10000's position of the Unicode sequence
	     * holder. */
	    if (uni == 0 || '0' == kbinput)
		retval = add_unicode_digit(kbinput, 0x10000, &uni);
	    else
		/* This isn't the second digit of a Unicode sequence.
		 * Return this character as the result. */
		retval = kbinput;
	    break;
	case 3:
	    /* Third digit: This may be any hexadecimal value.  Put it
	     * in the 0x1000's position of the Unicode sequence
	     * holder. */
	    retval = add_unicode_digit(kbinput, 0x1000, &uni);
	    break;
	case 4:
	    /* Fourth digit: This may be any hexadecimal value.  Put it
	     * in the 0x100's position of the Unicode sequence
	     * holder. */
	    retval = add_unicode_digit(kbinput, 0x100, &uni);
	    break;
	case 5:
	    /* Fifth digit: This may be any hexadecimal value.  Put it
	     * in the 0x10's position of the Unicode sequence holder. */
	    retval = add_unicode_digit(kbinput, 0x10, &uni);
	    break;
	case 6:
	    /* Sixth digit: This may be any hexadecimal value.  Put it
	     * in the 0x1's position of the Unicode sequence holder. */
	    retval = add_unicode_digit(kbinput, 0x1, &uni);
	    /* If this character is a valid hexadecimal value, then the
	     * Unicode sequence is complete. */
	    if (retval == ERR)
		retval = uni;
	    break;
	default:
	    /* If there are more than six digits, return this character
	     * as the result.  (Maybe we should produce an error
	     * instead?) */
	    retval = kbinput;
	    break;
    }

    /* If we have a result, reset the Unicode digit counter and the
     * Unicode sequence holder. */
    if (retval != ERR) {
	uni_digits = 0;
	uni = 0;
    }

#ifdef DEBUG
    fprintf(stderr, "get_unicode_kbinput(): kbinput = %d, uni_digits = %d, uni = %ld, retval = %ld\n", kbinput, uni_digits, uni, retval);
#endif

    return retval;
}
#endif /* ENABLE_UTF8 */

/* Translate a control character sequence: turn an ASCII non-control
 * character into its corresponding control character. */
int get_control_kbinput(int kbinput)
{
    int retval;

     /* Ctrl-Space (Ctrl-2, Ctrl-@, Ctrl-`) */
    if (kbinput == ' ' || kbinput == '2')
	retval = NANO_CONTROL_SPACE;
    /* Ctrl-/ (Ctrl-7, Ctrl-_) */
    else if (kbinput == '/')
	retval = NANO_CONTROL_7;
    /* Ctrl-3 (Ctrl-[, Esc) to Ctrl-7 (Ctrl-/, Ctrl-_) */
    else if ('3' <= kbinput && kbinput <= '7')
	retval = kbinput - 24;
    /* Ctrl-8 (Ctrl-?) */
    else if (kbinput == '8' || kbinput == '?')
	retval = NANO_CONTROL_8;
    /* Ctrl-@ (Ctrl-Space, Ctrl-2, Ctrl-`) to Ctrl-_ (Ctrl-/, Ctrl-7) */
    else if ('@' <= kbinput && kbinput <= '_')
	retval = kbinput - '@';
    /* Ctrl-` (Ctrl-2, Ctrl-Space, Ctrl-@) to Ctrl-~ (Ctrl-6, Ctrl-^) */
    else if ('`' <= kbinput && kbinput <= '~')
	retval = kbinput - '`';
    else
	retval = kbinput;

#ifdef DEBUG
    fprintf(stderr, "get_control_kbinput(): kbinput = %d, retval = %d\n", kbinput, retval);
#endif

    return retval;
}

/* Put the output-formatted characters in output back into the keystroke
 * buffer, so that they can be parsed and displayed as output again. */
void unparse_kbinput(char *output, size_t output_len)
{
    int *input;
    size_t i;

    if (output_len == 0)
	return;

    input = (int *)nmalloc(output_len * sizeof(int));

    for (i = 0; i < output_len; i++)
	input[i] = (int)output[i];

    unget_input(input, output_len);

    free(input);
}

/* Read in a stream of characters verbatim, and return the length of the
 * string in kbinput_len.  Assume nodelay(win) is FALSE. */
int *get_verbatim_kbinput(WINDOW *win, size_t *kbinput_len)
{
    int *retval;

    /* Turn off flow control characters if necessary so that we can type
     * them in verbatim, and turn the keypad off if necessary so that we
     * don't get extended keypad values. */
    if (ISSET(PRESERVE))
	disable_flow_control();
    if (!ISSET(REBIND_KEYPAD))
	keypad(win, FALSE);

    /* Read in a stream of characters and interpret it if possible. */
    retval = parse_verbatim_kbinput(win, kbinput_len);

    /* Turn flow control characters back on if necessary and turn the
     * keypad back on if necessary now that we're done. */
    if (ISSET(PRESERVE))
	enable_flow_control();
    if (!ISSET(REBIND_KEYPAD))
	keypad(win, TRUE);

    return retval;
}

/* Read in a stream of all available characters, and return the length
 * of the string in kbinput_len.  Translate the first few characters of
 * the input into the corresponding multibyte value if possible.  After
 * that, leave the input as-is. */
int *parse_verbatim_kbinput(WINDOW *win, size_t *kbinput_len)
{
    int *kbinput, *retval;

    /* Read in the first keystroke. */
    while ((kbinput = get_input(win, 1)) == NULL);

#ifdef ENABLE_UTF8
    if (using_utf8()) {
	/* Check whether the first keystroke is a valid hexadecimal
	 * digit. */
	long uni = get_unicode_kbinput(*kbinput);

	/* If the first keystroke isn't a valid hexadecimal digit, put
	 * back the first keystroke. */
	if (uni != ERR)
	    unget_input(kbinput, 1);

	/* Otherwise, read in keystrokes until we have a complete
	 * Unicode sequence, and put back the corresponding Unicode
	 * value. */
	else {
	    char *uni_mb;
	    int uni_mb_len, *seq, i;

	    if (win == edit)
		/* TRANSLATORS: This is displayed during the input of a
		 * six-digit hexadecimal Unicode character code. */
		statusbar(_("Unicode Input"));

	    while (uni == ERR) {
		while ((kbinput = get_input(win, 1)) == NULL);

		uni = get_unicode_kbinput(*kbinput);
	    }

	    /* Put back the multibyte equivalent of the Unicode
	     * value. */
	    uni_mb = make_mbchar(uni, &uni_mb_len);

	    seq = (int *)nmalloc(uni_mb_len * sizeof(int));

	    for (i = 0; i < uni_mb_len; i++)
		seq[i] = (unsigned char)uni_mb[i];

	    unget_input(seq, uni_mb_len);

	    free(seq);
	    free(uni_mb);
	}
    } else
#endif /* ENABLE_UTF8 */

	/* Put back the first keystroke. */
	unget_input(kbinput, 1);

    free(kbinput);

    /* Get the complete sequence, and save the characters in it as the
     * result. */
    *kbinput_len = get_key_buffer_len();
    retval = get_input(NULL, *kbinput_len);

    return retval;
}

#ifndef DISABLE_MOUSE
/* Handle any mouse event that may have occurred.  We currently handle
 * releases/clicks of the first mouse button.  If allow_shortcuts is
 * TRUE, releasing/clicking on a visible shortcut will put back the
 * keystroke associated with that shortcut.  If NCURSES_MOUSE_VERSION is
 * at least 2, we also currently handle presses of the fourth mouse
 * button (upward rolls of the mouse wheel) by putting back the
 * keystrokes to move up, and presses of the fifth mouse button
 * (downward rolls of the mouse wheel) by putting back the keystrokes to
 * move down.  We also store the coordinates of a mouse event that needs
 * to be handled in mouse_x and mouse_y, relative to the entire screen.
 * Return -1 on error, 0 if the mouse event needs to be handled, 1 if
 * it's been handled by putting back keystrokes that need to be handled.
 * or 2 if it's been ignored.  Assume that KEY_MOUSE has already been
 * read in. */
int get_mouseinput(int *mouse_x, int *mouse_y, bool allow_shortcuts)
{
    MEVENT mevent;
    bool in_bottomwin;

    *mouse_x = -1;
    *mouse_y = -1;

    /* First, get the actual mouse event. */
    if (getmouse(&mevent) == ERR)
	return -1;

    /* Save the screen coordinates where the mouse event took place. */
    *mouse_x = mevent.x;
    *mouse_y = mevent.y;

    in_bottomwin = wenclose(bottomwin, *mouse_y, *mouse_x);

    /* Handle releases/clicks of the first mouse button. */
    if (mevent.bstate & (BUTTON1_RELEASED | BUTTON1_CLICKED)) {
	/* If we're allowing shortcuts, the current shortcut list is
	 * being displayed on the last two lines of the screen, and the
	 * first mouse button was released on/clicked inside it, we need
	 * to figure out which shortcut was released on/clicked and put
	 * back the equivalent keystroke(s) for it. */
	if (allow_shortcuts && !ISSET(NO_HELP) && in_bottomwin) {
	    int i;
		/* The width of all the shortcuts, except for the last
		 * two, in the shortcut list in bottomwin. */
	    int j;
		/* The y-coordinate relative to the beginning of the
		 * shortcut list in bottomwin. */
	    size_t currslen;
		/* The number of shortcuts in the current shortcut
		 * list. */
	    const shortcut *s;
		/* The actual shortcut we released on, starting at the
		 * first one in the current shortcut list. */

	    /* Translate the mouse event coordinates so that they're
	     * relative to bottomwin. */
	    wmouse_trafo(bottomwin, mouse_y, mouse_x, FALSE);

	    /* Handle releases/clicks of the first mouse button on the
	     * statusbar elsewhere. */
	    if (*mouse_y == 0) {
		/* Restore the untranslated mouse event coordinates, so
		 * that they're relative to the entire screen again. */
		*mouse_x = mevent.x;
		*mouse_y = mevent.y;

		return 0;
	    }

	    /* Calculate the y-coordinate relative to the beginning of
	     * the shortcut list in bottomwin. */
	    j = *mouse_y - 1;

	    /* Get the shortcut lists' length. */
	    if (currshortcut == main_list)
		currslen = MAIN_VISIBLE;
	    else {
		currslen = length_of_list(currshortcut);

		/* We don't show any more shortcuts than the main list
		 * does. */
		if (currslen > MAIN_VISIBLE)
		    currslen = MAIN_VISIBLE;
	    }

	    /* Calculate the width of all of the shortcuts in the list
	     * except for the last two, which are longer by (COLS % i)
	     * columns so as to not waste space. */
	    if (currslen < 2)
		i = COLS / (MAIN_VISIBLE / 2);
	    else
		i = COLS / ((currslen / 2) + (currslen % 2));

	    /* Calculate the x-coordinate relative to the beginning of
	     * the shortcut list in bottomwin, and add it to j.  j
	     * should now be the index in the shortcut list of the
	     * shortcut we released/clicked on. */
	    j = (*mouse_x / i) * 2 + j;

	    /* Adjust j if we released on the last two shortcuts. */
	    if ((j >= currslen) && (*mouse_x % i < COLS % i))
		j -= 2;

	    /* Ignore releases/clicks of the first mouse button beyond
	     * the last shortcut. */
	    if (j >= currslen)
		return 2;

	    /* Go through the shortcut list to determine which shortcut
	     * we released/clicked on. */
	    s = currshortcut;

	    for (; j > 0; j--)
		s = s->next;

	    /* And put back the equivalent key.  Assume that each
	     * shortcut has, at the very least, an equivalent control
	     * key, an equivalent primary meta key sequence, or both. */
	    if (s->ctrlval != NANO_NO_KEY) {
		unget_kbinput(s->ctrlval, FALSE, FALSE);
		return 1;
	    } else if (s->metaval != NANO_NO_KEY) {
		unget_kbinput(s->metaval, TRUE, FALSE);
		return 1;
	    }
	} else
	    /* Handle releases/clicks of the first mouse button that
	     * aren't on the current shortcut list elsewhere. */
	    return 0;
    }
#if NCURSES_MOUSE_VERSION >= 2
    /* Handle presses of the fourth mouse button (upward rolls of the
     * mouse wheel) and presses of the fifth mouse button (downward
     * rolls of the mouse wheel) . */
    else if (mevent.bstate & (BUTTON4_PRESSED | BUTTON5_PRESSED)) {
	bool in_edit = wenclose(edit, mouse_y, mouse_x);

	if (in_bottomwin)
	    /* Translate the mouse event coordinates so that they're
	     * relative to bottomwin. */
	    wmouse_trafo(bottomwin, mouse_y, mouse_x, FALSE);

	if (in_edit || (in_bottomwin && *mouse_y == 0)) {
	    /* One upward roll of the mouse wheel is equivalent to
	     * moving up three lines, and one downward roll of the mouse
	     * wheel is equivalent to moving down three lines. */
	    for (i = 0; i < 3; i++)
		unget_kbinput((mevent.bstate & BUTTON4_PRESSED) ?
			NANO_PREVLINE_KEY : NANO_NEXTLINE_KEY, FALSE,
			FALSE);

	    return 1;
	} else
	    /* Ignore presses of the fourth mouse button and presses of
	     * the fifth mouse buttons that aren't on the edit window or
	     * the statusbar. */
	    return 2;
    }
#endif

    /* Ignore all other mouse events. */
    return 2;
}
#endif /* !DISABLE_MOUSE */

/* Return the shortcut corresponding to the values of kbinput (the key
 * itself), meta_key (whether the key is a meta sequence), and func_key
 * (whether the key is a function key), if any.  The shortcut will be
 * the first one in the list (control key, meta key sequence, function
 * key, other meta key sequence) for the corresponding function.  For
 * example, passing in a meta key sequence that corresponds to a
 * function with a control key, a function key, and a meta key sequence
 * will return the control key corresponding to that function. */
const shortcut *get_shortcut(const shortcut *s_list, int *kbinput, bool
	*meta_key, bool *func_key)
{
    const shortcut *s = s_list;
    size_t slen = length_of_list(s_list);

#ifdef DEBUG
    fprintf(stderr, "get_shortcut(): kbinput = %d, meta_key = %s, func_key = %s\n", *kbinput, *meta_key ? "TRUE" : "FALSE", *func_key ? "TRUE" : "FALSE");
#endif

    /* Check for shortcuts. */
    for (; slen > 0; slen--) {
	/* We've found a shortcut if:
	 *
	 * 1. The key exists.
	 * 2. The key is a control key in the shortcut list.
	 * 3. meta_key is TRUE and the key is the primary or
	 *    miscellaneous meta sequence in the shortcut list.
	 * 4. func_key is TRUE and the key is a function key in the
	 *    shortcut list. */

	if (*kbinput != NANO_NO_KEY && (*kbinput == s->ctrlval ||
		(*meta_key && (*kbinput == s->metaval || *kbinput ==
		s->miscval)) || (*func_key && *kbinput ==
		s->funcval))) {
	    break;
	}

	s = s->next;
    }

    /* Translate the shortcut to either its control key or its meta key
     * equivalent.  Assume that the shortcut has an equivalent control
     * key, an equivalent primary meta key sequence, or both. */
    if (slen > 0) {
	if (s->ctrlval != NANO_NO_KEY) {
	    *meta_key = FALSE;
	    *func_key = FALSE;
	    *kbinput = s->ctrlval;
	    return s;
	} else if (s->metaval != NANO_NO_KEY) {
	    *meta_key = TRUE;
	    *func_key = FALSE;
	    *kbinput = s->metaval;
	    return s;
	}
    }

    return NULL;
}

#ifndef NANO_TINY
/* Return the global toggle corresponding to the values of kbinput (the
 * key itself) and meta_key (whether the key is a meta sequence), if
 * any. */
const toggle *get_toggle(int kbinput, bool meta_key)
{
    const toggle *t = toggles;

#ifdef DEBUG
    fprintf(stderr, "get_toggle(): kbinput = %d, meta_key = %s\n", kbinput, meta_key ? "TRUE" : "FALSE");
#endif

    /* Check for toggles. */
    for (; t != NULL; t = t->next) {
	/* We've found a toggle if the key exists, meta_key is TRUE, and
	 * the key is in the meta key toggle list. */
	if (t->val != TOGGLE_NO_KEY && meta_key && kbinput == t->val)
	    break;
    }

    return t;
}
#endif /* !NANO_TINY */

/* Move to (x, y) in win, and display a line of n spaces with the
 * current attributes. */
void blank_line(WINDOW *win, int y, int x, int n)
{
    wmove(win, y, x);

    for (; n > 0; n--)
	waddch(win, ' ');
}

/* Blank the first line of the top portion of the window. */
void blank_titlebar(void)
{
    blank_line(topwin, 0, 0, COLS);
}

/* If the MORE_SPACE flag isn't set, blank the second line of the top
 * portion of the window. */
void blank_topbar(void)
{
    if (!ISSET(MORE_SPACE))
	blank_line(topwin, 1, 0, COLS);
}

/* Blank all the lines of the middle portion of the window, i.e. the
 * edit window. */
void blank_edit(void)
{
    int i;

    for (i = 0; i < editwinrows; i++)
	blank_line(edit, i, 0, COLS);
}

/* Blank the first line of the bottom portion of the window. */
void blank_statusbar(void)
{
    blank_line(bottomwin, 0, 0, COLS);
}

/* If the NO_HELP flag isn't set, blank the last two lines of the bottom
 * portion of the window. */
void blank_bottombars(void)
{
    if (!ISSET(NO_HELP)) {
	blank_line(bottomwin, 1, 0, COLS);
	blank_line(bottomwin, 2, 0, COLS);
    }
}

/* Check if the number of keystrokes needed to blank the statusbar has
 * been pressed.  If so, blank the statusbar, unless constant cursor
 * position display is on. */
void check_statusblank(void)
{
    if (statusblank > 0) {
	statusblank--;

	if (statusblank == 0 && !ISSET(CONST_UPDATE)) {
	    blank_statusbar();
	    wnoutrefresh(bottomwin);
	    reset_cursor();
	    wnoutrefresh(edit);
	}
    }
}

/* Convert buf into a string that can be displayed on screen.  The
 * caller wants to display buf starting with column start_col, and
 * extending for at most len columns.  start_col is zero-based.  len is
 * one-based, so len == 0 means you get "" returned.  The returned
 * string is dynamically allocated, and should be freed.  If dollars is
 * TRUE, the caller might put "$" at the beginning or end of the line if
 * it's too long. */
char *display_string(const char *buf, size_t start_col, size_t len, bool
	dollars)
{
    size_t start_index;
	/* Index in buf of the first character shown. */
    size_t column;
	/* Screen column that start_index corresponds to. */
    size_t alloc_len;
	/* The length of memory allocated for converted. */
    char *converted;
	/* The string we return. */
    size_t index;
	/* Current position in converted. */
    char *buf_mb;
    int buf_mb_len;

    /* If dollars is TRUE, make room for the "$" at the end of the
     * line. */
    if (dollars && len > 0 && strlenpt(buf) > start_col + len)
	len--;

    if (len == 0)
	return mallocstrcpy(NULL, "");

    buf_mb = charalloc(mb_cur_max());

    start_index = actual_x(buf, start_col);
    column = strnlenpt(buf, start_index);

    assert(column <= start_col);

    /* Make sure there's enough room for the initial character, whether
     * it's a multibyte control character, a non-control multibyte
     * character, a tab character, or a null terminator.  Rationale:
     *
     * multibyte control character followed by a null terminator:
     *     1 byte ('^') + mb_cur_max() bytes + 1 byte ('\0')
     * multibyte non-control character followed by a null terminator:
     *     mb_cur_max() bytes + 1 byte ('\0')
     * tab character followed by a null terminator:
     *     mb_cur_max() bytes + (tabsize - 1) bytes + 1 byte ('\0')
     *
     * Since tabsize has a minimum value of 1, it can substitute for 1
     * byte above. */
    alloc_len = (mb_cur_max() + tabsize + 1) * MAX_BUF_SIZE;
    converted = charalloc(alloc_len);

    index = 0;

    if (buf[start_index] != '\0' && buf[start_index] != '\t' &&
	(column < start_col || (dollars && column > 0))) {
	/* We don't display all of buf[start_index] since it starts to
	 * the left of the screen. */
	buf_mb_len = parse_mbchar(buf + start_index, buf_mb, NULL);

	if (is_cntrl_mbchar(buf_mb)) {
	    if (column < start_col) {
		char *ctrl_buf_mb = charalloc(mb_cur_max());
		int ctrl_buf_mb_len, i;

		ctrl_buf_mb = control_mbrep(buf_mb, ctrl_buf_mb,
			&ctrl_buf_mb_len);

		for (i = 0; i < ctrl_buf_mb_len; i++)
		    converted[index++] = ctrl_buf_mb[i];

		start_col += mbwidth(ctrl_buf_mb);

		free(ctrl_buf_mb);

		start_index += buf_mb_len;
	    }
	}
#ifdef ENABLE_UTF8
	else if (using_utf8() && mbwidth(buf_mb) == 2) {
	    if (column >= start_col) {
		converted[index++] = ' ';
		start_col++;
	    }

	    converted[index++] = ' ';
	    start_col++;

	    start_index += buf_mb_len;
	}
#endif
    }

    while (buf[start_index] != '\0') {
	buf_mb_len = parse_mbchar(buf + start_index, buf_mb, NULL);

	/* Make sure there's enough room for the next character, whether
	 * it's a multibyte control character, a non-control multibyte
	 * character, a tab character, or a null terminator. */
	if (index + mb_cur_max() + tabsize + 1 >= alloc_len - 1) {
	    alloc_len += (mb_cur_max() + tabsize + 1) * MAX_BUF_SIZE;
	    converted = charealloc(converted, alloc_len);
	}

	/* If buf contains a tab character, interpret it. */
	if (*buf_mb == '\t') {
#if !defined(NANO_TINY) && defined(ENABLE_NANORC)
	    if (ISSET(WHITESPACE_DISPLAY)) {
		int i;

		for (i = 0; i < whitespace_len[0]; i++)
		    converted[index++] = whitespace[i];
	    } else
#endif
		converted[index++] = ' ';
	    start_col++;
	    while (start_col % tabsize != 0) {
		converted[index++] = ' ';
		start_col++;
	    }
	/* If buf contains a control character, interpret it.  If buf
	 * contains an invalid multibyte control character, display it
	 * as such.*/
	} else if (is_cntrl_mbchar(buf_mb)) {
	    char *ctrl_buf_mb = charalloc(mb_cur_max());
	    int ctrl_buf_mb_len, i;

	    converted[index++] = '^';
	    start_col++;

	    ctrl_buf_mb = control_mbrep(buf_mb, ctrl_buf_mb,
		&ctrl_buf_mb_len);

	    for (i = 0; i < ctrl_buf_mb_len; i++)
		converted[index++] = ctrl_buf_mb[i];

	    start_col += mbwidth(ctrl_buf_mb);

	    free(ctrl_buf_mb);
	/* If buf contains a space character, interpret it. */
	} else if (*buf_mb == ' ') {
#if !defined(NANO_TINY) && defined(ENABLE_NANORC)
	    if (ISSET(WHITESPACE_DISPLAY)) {
		int i;

		for (i = whitespace_len[0]; i < whitespace_len[0] +
			whitespace_len[1]; i++)
		    converted[index++] = whitespace[i];
	    } else
#endif
		converted[index++] = ' ';
	    start_col++;
	/* If buf contains a non-control character, interpret it.  If
	 * buf contains an invalid multibyte non-control character,
	 * display it as such. */
	} else {
	    char *nctrl_buf_mb = charalloc(mb_cur_max());
	    int nctrl_buf_mb_len, i;

	    nctrl_buf_mb = mbrep(buf_mb, nctrl_buf_mb,
		&nctrl_buf_mb_len);

	    for (i = 0; i < nctrl_buf_mb_len; i++)
		converted[index++] = nctrl_buf_mb[i];

	    start_col += mbwidth(nctrl_buf_mb);

	    free(nctrl_buf_mb);
	}

	start_index += buf_mb_len;
    }

    free(buf_mb);

    assert(alloc_len >= index + 1);

    /* Null-terminate converted. */
    converted[index] = '\0';

    /* Make sure converted takes up no more than len columns. */
    index = actual_x(converted, len);
    null_at(&converted, index);

    return converted;
}

/* If path is NULL, we're in normal editing mode, so display the current
 * version of nano, the current filename, and whether the current file
 * has been modified on the titlebar.  If path isn't NULL, we're in the
 * file browser, and path contains the directory to start the file
 * browser in, so display the current version of nano and the contents
 * of path on the titlebar. */
void titlebar(const char *path)
{
    int space = COLS;
	/* The space we have available for display. */
    size_t verlen = strlenpt(PACKAGE_STRING) + 1;
	/* The length of the version message in columns, plus one for
	 * padding. */
    const char *prefix;
	/* "DIR:", "File:", or "New Buffer".  Goes before filename. */
    size_t prefixlen;
	/* The length of the prefix in columns, plus one for padding. */
    const char *state;
	/* "Modified", "View", or "".  Shows the state of this
	 * buffer. */
    size_t statelen = 0;
	/* The length of the state in columns, or the length of
	 * "Modified" if the state is blank and we're not in the file
	 * browser. */
    char *exppath = NULL;
	/* The filename, expanded for display. */
    bool newfie = FALSE;
	/* Do we say "New Buffer"? */
    bool dots = FALSE;
	/* Do we put an ellipsis before the path? */

    assert(path != NULL || openfile->filename != NULL);

    wattron(topwin, reverse_attr);

    blank_titlebar();

    /* space has to be at least 4: two spaces before the version message,
     * at least one character of the version message, and one space
     * after the version message. */
    if (space < 4)
	space = 0;
    else {
	/* Limit verlen to 1/3 the length of the screen in columns,
	 * minus three columns for spaces. */
	if (verlen > (COLS / 3) - 3)
	    verlen = (COLS / 3) - 3;
    }

    if (space >= 4) {
	/* Add a space after the version message, and account for both
	 * it and the two spaces before it. */
	mvwaddnstr(topwin, 0, 2, PACKAGE_STRING,
		actual_x(PACKAGE_STRING, verlen));
	verlen += 3;

	/* Account for the full length of the version message. */
	space -= verlen;
    }

#ifndef DISABLE_BROWSER
    /* Don't display the state if we're in the file browser. */
    if (path != NULL)
	state = "";
    else
#endif
	state = openfile->modified ? _("Modified") : ISSET(VIEW_MODE) ?
		_("View") : "";

    statelen = strlenpt((*state == '\0' && path == NULL) ?
	_("Modified") : state);

    /* If possible, add a space before state. */
    if (space > 0 && statelen < space)
	statelen++;
    else
	goto the_end;

#ifndef DISABLE_BROWSER
    /* path should be a directory if we're in the file browser. */
    if (path != NULL)
	prefix = _("DIR:");
    else
#endif
    if (openfile->filename[0] == '\0') {
	prefix = _("New Buffer");
	newfie = TRUE;
    } else
	prefix = _("File:");

    prefixlen = strnlenpt(prefix, space - statelen) + 1;

    /* If newfie is FALSE, add a space after prefix. */
    if (!newfie && prefixlen + statelen < space)
	prefixlen++;

    /* If we're not in the file browser, set path to the current
     * filename. */
    if (path == NULL)
	path = openfile->filename;

    /* Account for the full lengths of the prefix and the state. */
    if (space >= prefixlen + statelen)
	space -= prefixlen + statelen;
    else
	space = 0;
	/* space is now the room we have for the filename. */

    if (!newfie) {
	size_t lenpt = strlenpt(path), start_col;

	/* Don't set dots to TRUE if we have fewer than eight columns
	 * (i.e. one column for padding, plus seven columns for a
	 * filename). */
	dots = (space >= 8 && lenpt >= space);

	if (dots) {
	    start_col = lenpt - space + 3;
	    space -= 3;
	} else
	    start_col = 0;

	exppath = display_string(path, start_col, space, FALSE);
    }

    /* If dots is TRUE, we will display something like "File:
     * ...ename". */
    if (dots) {
	mvwaddnstr(topwin, 0, verlen - 1, prefix, actual_x(prefix,
		prefixlen));
	if (space <= -3 || newfie)
	    goto the_end;
	waddch(topwin, ' ');
	waddnstr(topwin, "...", space + 3);
	if (space <= 0)
	    goto the_end;
	waddstr(topwin, exppath);
    } else {
	size_t exppathlen = newfie ? 0 : strlenpt(exppath);
	    /* The length of the expanded filename. */

	/* There is room for the whole filename, so we center it. */
	mvwaddnstr(topwin, 0, verlen + ((space - exppathlen) / 3),
		prefix, actual_x(prefix, prefixlen));
	if (!newfie) {
	    waddch(topwin, ' ');
	    waddstr(topwin, exppath);
	}
    }

  the_end:
    free(exppath);

    if (state[0] != '\0') {
	if (statelen >= COLS - 1)
	    mvwaddnstr(topwin, 0, 0, state, actual_x(state, COLS));
	else {
	    assert(COLS - statelen - 1 >= 0);

	    mvwaddnstr(topwin, 0, COLS - statelen - 1, state,
		actual_x(state, statelen));
	}
    }

    wattroff(topwin, reverse_attr);

    wnoutrefresh(topwin);
    reset_cursor();
    wnoutrefresh(edit);
}

/* Mark the current file as modified if it isn't already, and then
 * update the titlebar to display the file's new status. */
void set_modified(void)
{
    if (!openfile->modified) {
	openfile->modified = TRUE;
	titlebar(NULL);
    }
}

/* Display a message on the statusbar, and set disable_cursorpos to
 * TRUE, so that the message won't be immediately overwritten if
 * constant cursor position display is on. */
void statusbar(const char *msg, ...)
{
    va_list ap;
    char *bar, *foo;
    size_t start_x, foo_len;
#if !defined(NANO_TINY) && defined(ENABLE_NANORC)
    bool old_whitespace;
#endif

    va_start(ap, msg);

    /* Curses mode is turned off.  If we use wmove() now, it will muck
     * up the terminal settings.  So we just use vfprintf(). */
    if (isendwin()) {
	vfprintf(stderr, msg, ap);
	va_end(ap);
	return;
    }

    blank_statusbar();

#if !defined(NANO_TINY) && defined(ENABLE_NANORC)
    old_whitespace = ISSET(WHITESPACE_DISPLAY);
    UNSET(WHITESPACE_DISPLAY);
#endif
    bar = charalloc(mb_cur_max() * (COLS - 3));
    vsnprintf(bar, mb_cur_max() * (COLS - 3), msg, ap);
    va_end(ap);
    foo = display_string(bar, 0, COLS - 4, FALSE);
#if !defined(NANO_TINY) && defined(ENABLE_NANORC)
    if (old_whitespace)
	SET(WHITESPACE_DISPLAY);
#endif
    free(bar);
    foo_len = strlenpt(foo);
    start_x = (COLS - foo_len - 4) / 2;

    wmove(bottomwin, 0, start_x);
    wattron(bottomwin, reverse_attr);
    waddstr(bottomwin, "[ ");
    waddstr(bottomwin, foo);
    free(foo);
    waddstr(bottomwin, " ]");
    wattroff(bottomwin, reverse_attr);
    wnoutrefresh(bottomwin);
    reset_cursor();
    wnoutrefresh(edit);
	/* Leave the cursor at its position in the edit window, not in
	 * the statusbar. */

    disable_cursorpos = TRUE;

    /* If we're doing quick statusbar blanking, and constant cursor
     * position display is off, blank the statusbar after only one
     * keystroke.  Otherwise, blank it after twenty-six keystrokes, as
     * Pico does. */
    statusblank =
#ifndef NANO_TINY
	ISSET(QUICK_BLANK) && !ISSET(CONST_UPDATE) ? 1 :
#endif
	26;
}

/* Display the shortcut list in s on the last two rows of the bottom
 * portion of the window. */
void bottombars(const shortcut *s)
{
    size_t i, colwidth, slen;

    if (ISSET(NO_HELP))
	return;

    if (s == main_list) {
	slen = MAIN_VISIBLE;

	assert(slen <= length_of_list(s));
    } else {
	slen = length_of_list(s);

	/* Don't show any more shortcuts than the main list does. */
	if (slen > MAIN_VISIBLE)
	    slen = MAIN_VISIBLE;
    }

    /* There will be this many characters per column, except for the
     * last two, which will be longer by (COLS % colwidth) columns so as
     * to not waste space.  We need at least three columns to display
     * anything properly. */
    colwidth = COLS / ((slen / 2) + (slen % 2));

    blank_bottombars();

    for (i = 0; i < slen; i++, s = s->next) {
	const char *keystr;
	char foo[4] = "";

	/* Yucky sentinel values that we can't handle a better way. */
	if (s->ctrlval == NANO_CONTROL_SPACE)
	    strcpy(foo, "^ ");
	else if (s->ctrlval == NANO_CONTROL_8)
	    strcpy(foo, "^?");
	/* Normal values.  Assume that the shortcut has an equivalent
	 * control key, meta key sequence, or both. */
	else if (s->ctrlval != NANO_NO_KEY)
	    sprintf(foo, "^%c", s->ctrlval + 64);
	else if (s->metaval != NANO_NO_KEY)
	    sprintf(foo, "M-%c", toupper(s->metaval));

	keystr = foo;

	wmove(bottomwin, 1 + i % 2, (i / 2) * colwidth);
	onekey(keystr, s->desc, colwidth + (COLS % colwidth));
    }

    wnoutrefresh(bottomwin);
    reset_cursor();
    wnoutrefresh(edit);
}

/* Write a shortcut key to the help area at the bottom of the window.
 * keystroke is e.g. "^G" and desc is e.g. "Get Help".  We are careful
 * to write at most len characters, even if len is very small and
 * keystroke and desc are long.  Note that waddnstr(,,(size_t)-1) adds
 * the whole string!  We do not bother padding the entry with blanks. */
void onekey(const char *keystroke, const char *desc, size_t len)
{
    size_t keystroke_len = strlenpt(keystroke) + 1;

    assert(keystroke != NULL && desc != NULL);

    wattron(bottomwin, reverse_attr);
    waddnstr(bottomwin, keystroke, actual_x(keystroke, len));
    wattroff(bottomwin, reverse_attr);

    if (len > keystroke_len)
	len -= keystroke_len;
    else
	len = 0;

    if (len > 0) {
	waddch(bottomwin, ' ');
	waddnstr(bottomwin, desc, actual_x(desc, len));
    }
}

/* Reset current_y, based on the position of current, and put the cursor
 * in the edit window at (current_y, current_x). */
void reset_cursor(void)
{
    /* If we haven't opened any files yet, put the cursor in the top
     * left corner of the edit window and get out. */
    if (openfile == NULL) {
	wmove(edit, 0, 0);
	return;
    }

    openfile->current_y = openfile->current->lineno -
	openfile->edittop->lineno;
    if (openfile->current_y < editwinrows) {
	size_t xpt = xplustabs();

	wmove(edit, openfile->current_y, xpt - get_page_start(xpt));
     }
}

/* edit_draw() takes care of the job of actually painting a line into
 * the edit window.  fileptr is the line to be painted, at row line of
 * the window.  converted is the actual string to be written to the
 * window, with tabs and control characters replaced by strings of
 * regular characters.  start is the column number of the first
 * character of this page.  That is, the first character of converted
 * corresponds to character number actual_x(fileptr->data, start) of the
 * line. */
void edit_draw(const filestruct *fileptr, const char *converted, int
	line, size_t start)
{
#if !defined(NANO_TINY) || defined(ENABLE_COLOR)
    size_t startpos = actual_x(fileptr->data, start);
	/* The position in fileptr->data of the leftmost character
	 * that displays at least partially on the window. */
    size_t endpos = actual_x(fileptr->data, start + COLS - 1) + 1;
	/* The position in fileptr->data of the first character that is
	 * completely off the window to the right.
	 *
	 * Note that endpos might be beyond the null terminator of the
	 * string. */
#endif

    assert(openfile != NULL && fileptr != NULL && converted != NULL);
    assert(strlenpt(converted) <= COLS);

    /* Just paint the string in any case (we'll add color or reverse on
     * just the text that needs it). */
    mvwaddstr(edit, line, 0, converted);

#ifdef ENABLE_COLOR
    /* If color syntaxes are available and turned on, we need to display
     * them. */
    if (openfile->colorstrings != NULL && !ISSET(NO_COLOR_SYNTAX)) {
	const colortype *tmpcolor = openfile->colorstrings;

	for (; tmpcolor != NULL; tmpcolor = tmpcolor->next) {
	    int x_start;
		/* Starting column for mvwaddnstr.  Zero-based. */
	    int paintlen;
		/* Number of chars to paint on this line.  There are
		 * COLS characters on a whole line. */
	    size_t index;
		/* Index in converted where we paint. */
	    regmatch_t startmatch;
		/* Match position for start_regex. */
	    regmatch_t endmatch;
		/* Match position for end_regex. */

	    if (tmpcolor->bright)
		wattron(edit, A_BOLD);
	    wattron(edit, COLOR_PAIR(tmpcolor->pairnum));
	    /* Two notes about regexec().  A return value of zero means
	     * that there is a match.  Also, rm_eo is the first
	     * non-matching character after the match. */

	    /* First case, tmpcolor is a single-line expression. */
	    if (tmpcolor->end == NULL) {
		size_t k = 0;

		/* We increment k by rm_eo, to move past the end of the
		 * last match.  Even though two matches may overlap, we
		 * want to ignore them, so that we can highlight e.g. C
		 * strings correctly. */
		while (k < endpos) {
		    /* Note the fifth parameter to regexec().  It says
		     * not to match the beginning-of-line character
		     * unless k is zero.  If regexec() returns
		     * REG_NOMATCH, there are no more matches in the
		     * line. */
		    if (regexec(tmpcolor->start, &fileptr->data[k], 1,
			&startmatch, (k == 0) ? 0 : REG_NOTBOL) ==
			REG_NOMATCH)
			break;
		    /* Translate the match to the beginning of the
		     * line. */
		    startmatch.rm_so += k;
		    startmatch.rm_eo += k;

		    /* Skip over a zero-length regex match. */
		    if (startmatch.rm_so == startmatch.rm_eo)
			startmatch.rm_eo++;
		    else if (startmatch.rm_so < endpos &&
			startmatch.rm_eo > startpos) {
			x_start = (startmatch.rm_so <= startpos) ? 0 :
				strnlenpt(fileptr->data,
				startmatch.rm_so) - start;

			index = actual_x(converted, x_start);

			paintlen = actual_x(converted + index,
				strnlenpt(fileptr->data,
				startmatch.rm_eo) - start - x_start);

			assert(0 <= x_start && 0 <= paintlen);

			mvwaddnstr(edit, line, x_start, converted +
				index, paintlen);
		    }
		    k = startmatch.rm_eo;
		}
	    } else {
		/* This is a multi-line regex.  There are two steps.
		 * First, we have to see if the beginning of the line is
		 * colored by a start on an earlier line, and an end on
		 * this line or later.
		 *
		 * We find the first line before fileptr matching the
		 * start.  If every match on that line is followed by an
		 * end, then go to step two.  Otherwise, find the next
		 * line after start_line matching the end.  If that line
		 * is not before fileptr, then paint the beginning of
		 * this line. */
		const filestruct *start_line = fileptr->prev;
		    /* The first line before fileptr matching start. */
		regoff_t start_col;
		    /* Where it starts in that line. */
		const filestruct *end_line;

		while (start_line != NULL && regexec(tmpcolor->start,
			start_line->data, 1, &startmatch, 0) ==
			REG_NOMATCH) {
		    /* If there is an end on this line, there is no need
		     * to look for starts on earlier lines. */
		    if (regexec(tmpcolor->end, start_line->data, 0,
			NULL, 0) == 0)
			goto step_two;
		    start_line = start_line->prev;
		}

		/* Skip over a zero-length regex match. */
		if (startmatch.rm_so == startmatch.rm_eo)
		    startmatch.rm_eo++;
		else {
		    /* No start found, so skip to the next step. */
		    if (start_line == NULL)
			goto step_two;
		    /* Now start_line is the first line before fileptr
		     * containing a start match.  Is there a start on
		     * this line not followed by an end on this line? */
		    start_col = 0;
		    while (TRUE) {
			start_col += startmatch.rm_so;
			startmatch.rm_eo -= startmatch.rm_so;
			if (regexec(tmpcolor->end, start_line->data +
				start_col + startmatch.rm_eo, 0, NULL,
				(start_col + startmatch.rm_eo == 0) ?
				0 : REG_NOTBOL) == REG_NOMATCH)
			    /* No end found after this start. */
			    break;
			start_col++;
			if (regexec(tmpcolor->start, start_line->data +
				start_col, 1, &startmatch,
				REG_NOTBOL) == REG_NOMATCH)
			    /* No later start on this line. */
			    goto step_two;
		    }
		    /* Indeed, there is a start not followed on this
		     * line by an end. */

		    /* We have already checked that there is no end
		     * before fileptr and after the start.  Is there an
		     * end after the start at all?  We don't paint
		     * unterminated starts. */
		    end_line = fileptr;
		    while (end_line != NULL && regexec(tmpcolor->end,
			end_line->data, 1, &endmatch, 0) == REG_NOMATCH)
			end_line = end_line->next;

		    /* No end found, or it is too early. */
		    if (end_line == NULL || (end_line == fileptr &&
			endmatch.rm_eo <= startpos))
			goto step_two;

		    /* Now paint the start of fileptr.  If the start of
		     * fileptr is on a different line from the end,
		     * paintlen is -1, meaning that everything on the
		     * line gets painted.  Otherwise, paintlen is the
		     * expanded location of the end of the match minus
		     * the expanded location of the beginning of the
		     * page. */
		    if (end_line != fileptr)
			paintlen = -1;
		    else
			paintlen = actual_x(converted,
				strnlenpt(fileptr->data,
				endmatch.rm_eo) - start);

		    mvwaddnstr(edit, line, 0, converted, paintlen);

  step_two:
		    /* Second step, we look for starts on this line. */
		    start_col = 0;

		    while (start_col < endpos) {
			if (regexec(tmpcolor->start, fileptr->data +
				start_col, 1, &startmatch, (start_col ==
				0) ? 0 : REG_NOTBOL) == REG_NOMATCH ||
				start_col + startmatch.rm_so >= endpos)
			    /* No more starts on this line. */
			    break;
			/* Translate the match to be relative to the
			 * beginning of the line. */
			startmatch.rm_so += start_col;
			startmatch.rm_eo += start_col;

			x_start = (startmatch.rm_so <= startpos) ? 0 :
				strnlenpt(fileptr->data,
				startmatch.rm_so) - start;

			index = actual_x(converted, x_start);

			if (regexec(tmpcolor->end, fileptr->data +
				startmatch.rm_eo, 1, &endmatch,
				(startmatch.rm_eo == 0) ? 0 :
				REG_NOTBOL) == 0) {
			    /* Translate the end match to be relative to
			     * the beginning of the line. */
			    endmatch.rm_so += startmatch.rm_eo;
			    endmatch.rm_eo += startmatch.rm_eo;
			    /* There is an end on this line.  But does
			     * it appear on this page, and is the match
			     * more than zero characters long? */
			    if (endmatch.rm_eo > startpos &&
				endmatch.rm_eo > startmatch.rm_so) {
				paintlen = actual_x(converted + index,
					strnlenpt(fileptr->data,
					endmatch.rm_eo) - start -
					x_start);

				assert(0 <= x_start && x_start < COLS);

				mvwaddnstr(edit, line, x_start,
					converted + index, paintlen);
			    }
			} else {
			    /* There is no end on this line.  But we
			     * haven't yet looked for one on later
			     * lines. */
			    end_line = fileptr->next;

			    while (end_line != NULL &&
				regexec(tmpcolor->end, end_line->data,
				0, NULL, 0) == REG_NOMATCH)
				end_line = end_line->next;

			    if (end_line != NULL) {
				assert(0 <= x_start && x_start < COLS);

				mvwaddnstr(edit, line, x_start,
					converted + index, -1);
				/* We painted to the end of the line, so
				 * don't bother checking any more
				 * starts. */
				break;
			    }
			}
			start_col = startmatch.rm_so + 1;
		    }
		}
	    }

	    wattroff(edit, A_BOLD);
	    wattroff(edit, COLOR_PAIR(tmpcolor->pairnum));
	}
    }
#endif /* ENABLE_COLOR */

#ifndef NANO_TINY
    /* If the mark is on, we need to display it. */
    if (openfile->mark_set && (fileptr->lineno <=
	openfile->mark_begin->lineno || fileptr->lineno <=
	openfile->current->lineno) && (fileptr->lineno >=
	openfile->mark_begin->lineno || fileptr->lineno >=
	openfile->current->lineno)) {
	/* fileptr is at least partially selected. */
	const filestruct *top;
	    /* Either current or mark_begin, whichever is first. */
	size_t top_x;
	    /* current_x or mark_begin_x, corresponding to top. */
	const filestruct *bot;
	size_t bot_x;
	int x_start;
	    /* Starting column for mvwaddnstr().  Zero-based. */
	int paintlen;
	    /* Number of characters to paint on this line.  There are
	     * COLS characters on a whole line. */
	size_t index;
	    /* Index in converted where we paint. */

	mark_order(&top, &top_x, &bot, &bot_x, NULL);

	if (top->lineno < fileptr->lineno || top_x < startpos)
	    top_x = startpos;
	if (bot->lineno > fileptr->lineno || bot_x > endpos)
	    bot_x = endpos;

	/* The selected bit of fileptr is on this page. */
	if (top_x < endpos && bot_x > startpos) {
	    assert(startpos <= top_x);

	    /* x_start is the expanded location of the beginning of the
	     * mark minus the beginning of the page. */
	    x_start = strnlenpt(fileptr->data, top_x) - start;

	    /* If the end of the mark is off the page, paintlen is -1,
	     * meaning that everything on the line gets painted.
	     * Otherwise, paintlen is the expanded location of the end
	     * of the mark minus the expanded location of the beginning
	     * of the mark. */
	    if (bot_x >= endpos)
		paintlen = -1;
	    else
		paintlen = strnlenpt(fileptr->data, bot_x) - (x_start +
			start);

	    /* If x_start is before the beginning of the page, shift
	     * paintlen x_start characters to compensate, and put
	     * x_start at the beginning of the page. */
	    if (x_start < 0) {
		paintlen += x_start;
		x_start = 0;
	    }

	    assert(x_start >= 0 && x_start <= strlen(converted));

	    index = actual_x(converted, x_start);

	    if (paintlen > 0)
		paintlen = actual_x(converted + index, paintlen);

	    wattron(edit, reverse_attr);
	    mvwaddnstr(edit, line, x_start, converted + index,
		paintlen);
	    wattroff(edit, reverse_attr);
	}
    }
#endif /* !NANO_TINY */
}

/* Just update one line in the edit buffer.  This is basically a wrapper
 * for edit_draw().  The line will be displayed starting with
 * fileptr->data[index].  Likely arguments are current_x or zero. */
void update_line(const filestruct *fileptr, size_t index)
{
    int line;
	/* The line in the edit window that we want to update. */
    char *converted;
	/* fileptr->data converted to have tabs and control characters
	 * expanded. */
    size_t page_start;

    assert(fileptr != NULL);

    line = fileptr->lineno - openfile->edittop->lineno;

    if (line < 0 || line >= editwinrows)
	return;

    /* First, blank out the line. */
    blank_line(edit, line, 0, COLS);

    /* Next, convert variables that index the line to their equivalent
     * positions in the expanded line. */
    index = strnlenpt(fileptr->data, index);
    page_start = get_page_start(index);

    /* Expand the line, replacing tabs with spaces, and control
     * characters with their displayed forms. */
    converted = display_string(fileptr->data, page_start, COLS, TRUE);

    /* Paint the line. */
    edit_draw(fileptr, converted, line, page_start);
    free(converted);

    if (page_start > 0)
	mvwaddch(edit, line, 0, '$');
    if (strlenpt(fileptr->data) > page_start + COLS)
	mvwaddch(edit, line, COLS - 1, '$');
}

/* Return TRUE if we need an update after moving horizontally, and FALSE
 * otherwise.  We need one if the mark is on or if pww_save and
 * placewewant are on different pages. */
bool need_horizontal_update(size_t pww_save)
{
    return
#ifndef NANO_TINY
	openfile->mark_set ||
#endif
	get_page_start(pww_save) !=
	get_page_start(openfile->placewewant);
}

/* Return TRUE if we need an update after moving vertically, and FALSE
 * otherwise.  We need one if the mark is on or if pww_save and
 * placewewant are on different pages. */
bool need_vertical_update(size_t pww_save)
{
    return
#ifndef NANO_TINY
	openfile->mark_set ||
#endif
	get_page_start(pww_save) !=
	get_page_start(openfile->placewewant);
}

/* Scroll the edit window in the given direction and the given number
 * of lines, and draw new lines on the blank lines left after the
 * scrolling.  direction is the direction to scroll, either UP_DIR or
 * DOWN_DIR, and nlines is the number of lines to scroll.  We change
 * edittop, and assume that current and current_x are up to date.  We
 * also assume that scrollok(edit) is FALSE. */
void edit_scroll(scroll_dir direction, ssize_t nlines)
{
    bool do_redraw = need_vertical_update(0);
    const filestruct *foo;
    ssize_t i;

    /* Don't bother scrolling less than one line. */
    if (nlines < 1)
	return;

    /* Part 1: nlines is the number of lines we're going to scroll the
     * text of the edit window. */

    /* Move the top line of the edit window up or down (depending on the
     * value of direction) nlines lines, or as many lines as we can if
     * there are fewer than nlines lines available. */
    for (i = nlines; i > 0; i--) {
	if (direction == UP_DIR) {
	    if (openfile->edittop == openfile->fileage)
		break;
	    openfile->edittop = openfile->edittop->prev;
	} else {
	    if (openfile->edittop == openfile->filebot)
		break;
	    openfile->edittop = openfile->edittop->next;
	}
    }

    /* Limit nlines to the number of lines we could scroll. */
    nlines -= i;

    /* Don't bother scrolling zero lines or more than the number of
     * lines in the edit window minus one; in both cases, get out, and
     * call edit_refresh() beforehand if we need to. */
    if (nlines == 0 || nlines >= editwinrows) {
	if (do_redraw || nlines >= editwinrows)
	    edit_refresh();
	return;
    }

    /* Scroll the text of the edit window up or down nlines lines,
     * depending on the value of direction. */
    scrollok(edit, TRUE);
    wscrl(edit, (direction == UP_DIR) ? -nlines : nlines);
    scrollok(edit, FALSE);

    /* Part 2: nlines is the number of lines in the scrolled region of
     * the edit window that we need to draw. */

    /* If the top or bottom line of the file is now visible in the edit
     * window, we need to draw the entire edit window. */
    if ((direction == UP_DIR && openfile->edittop ==
	openfile->fileage) || (direction == DOWN_DIR &&
	openfile->edittop->lineno + editwinrows - 1 >=
	openfile->filebot->lineno))
	nlines = editwinrows;

    /* If the scrolled region contains only one line, and the line
     * before it is visible in the edit window, we need to draw it too.
     * If the scrolled region contains more than one line, and the lines
     * before and after the scrolled region are visible in the edit
     * window, we need to draw them too. */
    nlines += (nlines == 1) ? 1 : 2;

    if (nlines > editwinrows)
	nlines = editwinrows;

    /* If we scrolled up, we're on the line before the scrolled
     * region. */
    foo = openfile->edittop;

    /* If we scrolled down, move down to the line before the scrolled
     * region. */
    if (direction == DOWN_DIR) {
	for (i = editwinrows - nlines; i > 0 && foo != NULL; i--)
	    foo = foo->next;
    }

    /* Draw new lines on any blank lines before or inside the scrolled
     * region.  If we scrolled down and we're on the top line, or if we
     * scrolled up and we're on the bottom line, the line won't be
     * blank, so we don't need to draw it unless the mark is on or we're
     * not on the first page. */
    for (i = nlines; i > 0 && foo != NULL; i--) {
	if ((i == nlines && direction == DOWN_DIR) || (i == 1 &&
		direction == UP_DIR)) {
	    if (do_redraw)
		update_line(foo, (foo == openfile->current) ?
			openfile->current_x : 0);
	} else
	    update_line(foo, (foo == openfile->current) ?
		openfile->current_x : 0);
	foo = foo->next;
    }
}

/* Update any lines between old_current and current that need to be
 * updated.  Use this if we've moved without changing any text. */
void edit_redraw(const filestruct *old_current, size_t pww_save)
{
    bool do_redraw = need_vertical_update(0) ||
	need_vertical_update(pww_save);
    const filestruct *foo = NULL;

    /* If either old_current or current is offscreen, scroll the edit
     * window until it's onscreen and get out. */
    if (old_current->lineno < openfile->edittop->lineno ||
	old_current->lineno >= openfile->edittop->lineno +
	editwinrows || openfile->current->lineno <
	openfile->edittop->lineno || openfile->current->lineno >=
	openfile->edittop->lineno + editwinrows) {
	filestruct *old_edittop = openfile->edittop;
	ssize_t nlines;

#ifndef NANO_TINY
	/* If the mark is on, update all the lines between old_current
	 * and either the old first line or old last line (depending on
	 * whether we've scrolled up or down) of the edit window. */
	if (openfile->mark_set) {
	    ssize_t old_lineno;

	    if (old_edittop->lineno < openfile->edittop->lineno)
		old_lineno = old_edittop->lineno;
	    else
		old_lineno = (old_edittop->lineno + editwinrows <=
			openfile->filebot->lineno) ?
			old_edittop->lineno + editwinrows :
			openfile->filebot->lineno;

	    foo = old_current;

	    while (foo->lineno != old_lineno) {
		update_line(foo, 0);

		foo = (foo->lineno > old_lineno) ? foo->prev :
			foo->next;
	    }
	}
#endif /* !NANO_TINY */

	/* Put edittop in range of current, get the difference in lines
	 * between the original edittop and the current edittop, and
	 * then restore the original edittop. */
	edit_update(
#ifndef NANO_TINY
		ISSET(SMOOTH_SCROLL) ? NONE :
#endif
		CENTER);

	nlines = openfile->edittop->lineno - old_edittop->lineno;

	openfile->edittop = old_edittop;

	/* Update old_current if we're not on the same page as
	 * before. */
	if (do_redraw)
	    update_line(old_current, 0);

	/* Scroll the edit window up or down until edittop is in range
	 * of current. */
	if (nlines < 0)
	    edit_scroll(UP_DIR, -nlines);
	else
	    edit_scroll(DOWN_DIR, nlines);

#ifndef NANO_TINY
	/* If the mark is on, update all the lines between the old first
	 * line or old last line of the edit window (depending on
	 * whether we've scrolled up or down) and current. */
	if (openfile->mark_set) {
	    while (foo->lineno != openfile->current->lineno) {
		update_line(foo, 0);

		foo = (foo->lineno > openfile->current->lineno) ?
			foo->prev : foo->next;
	    }
	}
#endif /* !NANO_TINY */

	return;
    }

    /* Update old_current and current if we're not on the same page as
     * before.  If the mark is on, update all the lines between
     * old_current and current too. */
    foo = old_current;

    while (foo != openfile->current) {
	if (do_redraw)
	    update_line(foo, 0);

#ifndef NANO_TINY
	if (!openfile->mark_set)
#endif
	    break;

#ifndef NANO_TINY
	foo = (foo->lineno > openfile->current->lineno) ? foo->prev :
		foo->next;
#endif
    }

    if (do_redraw)
	update_line(openfile->current, openfile->current_x);
}

/* Refresh the screen without changing the position of lines.  Use this
 * if we've moved and changed text. */
void edit_refresh(void)
{
    const filestruct *foo;
    int nlines;

    if (openfile->current->lineno < openfile->edittop->lineno ||
	openfile->current->lineno >= openfile->edittop->lineno +
	editwinrows)
	/* Put the top line of the edit window in range of the current
	 * line. */
	edit_update(
#ifndef NANO_TINY
		ISSET(SMOOTH_SCROLL) ? NONE :
#endif
		CENTER);

    foo = openfile->edittop;

#ifdef DEBUG
    fprintf(stderr, "edit_refresh(): edittop->lineno = %ld\n", (long)openfile->edittop->lineno);
#endif

    for (nlines = 0; nlines < editwinrows && foo != NULL; nlines++) {
	update_line(foo, (foo == openfile->current) ?
		openfile->current_x : 0);
	foo = foo->next;
    }

    for (; nlines < editwinrows; nlines++)
	blank_line(edit, nlines, 0, COLS);

    reset_cursor();
    wnoutrefresh(edit);
}

/* Move edittop to put it in range of current, keeping current in the
 * same place.  location determines how we move it: if it's CENTER, we
 * center current, and if it's NONE, we put current current_y lines
 * below edittop. */
void edit_update(update_type location)
{
    filestruct *foo = openfile->current;
    int goal;

    /* If location is CENTER, we move edittop up (editwinrows / 2)
     * lines.  This puts current at the center of the screen.  If
     * location is NONE, we move edittop up current_y lines if current_y
     * is in range of the screen, 0 lines if current_y is less than 0,
     * or (editwinrows - 1) lines if current_y is greater than
     * (editwinrows - 1).  This puts current at the same place on the
     * screen as before, or at the top or bottom of the screen if
     * edittop is beyond either. */
    if (location == CENTER)
	goal = editwinrows / 2;
    else {
	goal = openfile->current_y;

	/* Limit goal to (editwinrows - 1) lines maximum. */
	if (goal > editwinrows - 1)
	    goal = editwinrows - 1;
    }

    for (; goal > 0 && foo->prev != NULL; goal--)
	foo = foo->prev;

    openfile->edittop = foo;
}

/* Unconditionally redraw the entire screen. */
void total_redraw(void)
{
#ifdef USE_SLANG
    /* Slang curses emulation brain damage, part 4: Slang doesn't define
     * curscr. */
    SLsmg_touch_screen();
    SLsmg_refresh();
#else
    wrefresh(curscr);
#endif
}

/* Unconditionally redraw the entire screen, and then refresh it using
 * the current file. */
void total_refresh(void)
{
    total_redraw();
    titlebar(NULL);
    edit_refresh();
    bottombars(currshortcut);
}

/* Display the main shortcut list on the last two rows of the bottom
 * portion of the window. */
void display_main_list(void)
{
    bottombars(main_list);
}

/* If constant is TRUE, we display the current cursor position only if
 * disable_cursorpos is FALSE.  Otherwise, we display it
 * unconditionally and set disable_cursorpos to FALSE.  If constant is
 * TRUE and disable_cursorpos is TRUE, we also set disable_cursorpos to
 * FALSE, so that we leave the current statusbar alone this time, and
 * display the current cursor position next time. */
void do_cursorpos(bool constant)
{
    filestruct *f;
    char c;
    size_t i, cur_xpt = xplustabs() + 1;
    size_t cur_lenpt = strlenpt(openfile->current->data) + 1;
    int linepct, colpct, charpct;

    assert(openfile->fileage != NULL && openfile->current != NULL);

    f = openfile->current->next;
    c = openfile->current->data[openfile->current_x];

    openfile->current->next = NULL;
    openfile->current->data[openfile->current_x] = '\0';

    i = get_totsize(openfile->fileage, openfile->current);

    openfile->current->data[openfile->current_x] = c;
    openfile->current->next = f;

    if (constant && disable_cursorpos) {
	disable_cursorpos = FALSE;
	return;
    }

    /* Display the current cursor position on the statusbar, and set
     * disable_cursorpos to FALSE. */
    linepct = 100 * openfile->current->lineno /
	openfile->filebot->lineno;
    colpct = 100 * cur_xpt / cur_lenpt;
    charpct = (openfile->totsize == 0) ? 0 : 100 * i /
	openfile->totsize;

    statusbar(
	_("line %ld/%ld (%d%%), col %lu/%lu (%d%%), char %lu/%lu (%d%%)"),
	(long)openfile->current->lineno,
	(long)openfile->filebot->lineno, linepct,
	(unsigned long)cur_xpt, (unsigned long)cur_lenpt, colpct,
	(unsigned long)i, (unsigned long)openfile->totsize, charpct);

    disable_cursorpos = FALSE;
}

/* Unconditionally display the current cursor position. */
void do_cursorpos_void(void)
{
    do_cursorpos(FALSE);
}

/* Highlight the current word being replaced or spell checked.  We
 * expect word to have tabs and control characters expanded. */
void do_replace_highlight(bool highlight, const char *word)
{
    size_t y = xplustabs(), word_len = strlenpt(word);

    y = get_page_start(y) + COLS - y;
	/* Now y is the number of columns that we can display on this
	 * line. */

    assert(y > 0);

    if (word_len > y)
	y--;

    reset_cursor();
    wnoutrefresh(edit);

    if (highlight)
	wattron(edit, reverse_attr);

    /* This is so we can show zero-length matches. */
    if (word_len == 0)
	waddch(edit, ' ');
    else
	waddnstr(edit, word, actual_x(word, y));

    if (word_len > y)
	waddch(edit, '$');

    if (highlight)
	wattroff(edit, reverse_attr);
}

#ifdef NANO_EXTRA
#define CREDIT_LEN 55
#define XLCREDIT_LEN 8

/* Easter egg: Display credits.  Assume nodelay(edit) and scrollok(edit)
 * are FALSE. */
void do_credits(void)
{
    bool old_more_space = ISSET(MORE_SPACE);
    bool old_no_help = ISSET(NO_HELP);
    int kbinput = ERR, crpos = 0, xlpos = 0;
    const char *credits[CREDIT_LEN] = {
	NULL,				/* "The nano text editor" */
	NULL,				/* "version" */
	VERSION,
	"",
	NULL,				/* "Brought to you by:" */
	"Chris Allegretta",
	"Jordi Mallach",
	"Adam Rogoyski",
	"Rob Siemborski",
	"Rocco Corsi",
	"David Lawrence Ramsey",
	"David Benbennick",
	"Mike Frysinger",
	"Ken Tyler",
	"Sven Guckes",
	NULL,				/* credits[15], handled below. */
	"Pauli Virtanen",
	"Daniele Medri",
	"Clement Laforet",
	"Tedi Heriyanto",
	"Bill Soudan",
	"Christian Weisgerber",
	"Erik Andersen",
	"Big Gaute",
	"Joshua Jensen",
	"Ryan Krebs",
	"Albert Chin",
	"",
	NULL,				/* "Special thanks to:" */
	"Plattsburgh State University",
	"Benet Laboratories",
	"Amy Allegretta",
	"Linda Young",
	"Jeremy Robichaud",
	"Richard Kolb II",
	NULL,				/* "The Free Software Foundation" */
	"Linus Torvalds",
	NULL,				/* "For ncurses:" */
	"Thomas Dickey",
	"Pavel Curtis",
	"Zeyd Ben-Halim",
	"Eric S. Raymond",
	NULL,				/* "and anyone else we forgot..." */
	NULL,				/* "Thank you for using nano!" */
	"",
	"",
	"",
	"",
	"(C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007",
	"Free Software Foundation, Inc.",
	"",
	"",
	"",
	"",
	"http://www.nano-editor.org/"
    };

    const char *xlcredits[XLCREDIT_LEN] = {
	N_("The nano text editor"),
	N_("version"),
	N_("Brought to you by:"),
	N_("Special thanks to:"),
	N_("The Free Software Foundation"),
	N_("For ncurses:"),
	N_("and anyone else we forgot..."),
	N_("Thank you for using nano!")
    };

    /* credits[15]: Make sure this name is displayed properly, since we
     * can't dynamically assign it above, using Unicode 00F6 (Latin
     * Small Letter O with Diaresis) if applicable. */
    credits[15] =
#ifdef ENABLE_UTF8
	 using_utf8() ? "Florian K\xC3\xB6nig" :
#endif
	"Florian K\xF6nig";

    if (!old_more_space || !old_no_help) {
	SET(MORE_SPACE);
	SET(NO_HELP);
	window_init();
    }

    curs_set(0);
    nodelay(edit, TRUE);

    blank_titlebar();
    blank_topbar();
    blank_edit();
    blank_statusbar();
    blank_bottombars();

    wrefresh(topwin);
    wrefresh(edit);
    wrefresh(bottomwin);
    napms(700);

    for (crpos = 0; crpos < CREDIT_LEN + editwinrows / 2; crpos++) {
	if ((kbinput = wgetch(edit)) != ERR)
	    break;

	if (crpos < CREDIT_LEN) {
	    const char *what;
	    size_t start_x;

	    if (credits[crpos] == NULL) {
		assert(0 <= xlpos && xlpos < XLCREDIT_LEN);

		what = _(xlcredits[xlpos]);
		xlpos++;
	    } else
		what = credits[crpos];

	    start_x = COLS / 2 - strlenpt(what) / 2 - 1;
	    mvwaddstr(edit, editwinrows - 1 - (editwinrows % 2),
		start_x, what);
	}

	wrefresh(edit);

	if ((kbinput = wgetch(edit)) != ERR)
	    break;
	napms(700);

	scrollok(edit, TRUE);
	wscrl(edit, 1);
	scrollok(edit, FALSE);
	wrefresh(edit);

	if ((kbinput = wgetch(edit)) != ERR)
	    break;
	napms(700);

	scrollok(edit, TRUE);
	wscrl(edit, 1);
	scrollok(edit, FALSE);
	wrefresh(edit);
    }

    if (kbinput != ERR)
	ungetch(kbinput);

    if (!old_more_space || !old_no_help) {
	UNSET(MORE_SPACE);
	UNSET(NO_HELP);
	window_init();
    }

    curs_set(1);
    nodelay(edit, FALSE);

    total_refresh();
}
#endif /* NANO_EXTRA */