winio.c

/* $Id$ */
/**************************************************************************
 *   winio.c                                                              *
 *                                                                        *
 *   Copyright (C) 1999-2004 Chris Allegretta                             *
 *   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 2, 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., 675 Mass Ave, Cambridge, MA 02139, USA.            *
 *                                                                        *
 **************************************************************************/

#include "config.h"

#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <assert.h>
#include "proto.h"
#include "nano.h"

static int statblank = 0;	/* Number of keystrokes left after
				   we call statusbar(), before we
				   actually blank the statusbar */

/* 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 Hurd console (a.k.a. the Mach
 * console), xterm, rxvt, and Eterm.  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 Hurd 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 Hurd console; the former is
 *   omitted.  (Same as above.)
 * - F13 on FreeBSD console == End on Hurd console; the former is
 *   omitted.  (Same as above.)
 *
 * Note that Center (5) on the numeric keypad with NumLock off can also
 * be the Begin key. */

#ifndef NANO_SMALL
/* Reset all the input routines that rely on character sequences. */
void reset_kbinput(void)
{
    get_translated_kbinput(0, NULL, TRUE);
    get_ascii_kbinput(0, 0, TRUE);
    get_untranslated_kbinput(0, 0, FALSE, TRUE);
}
#endif

/* Read in a single input character.  If it's ignored, swallow it and go
 * on.  Otherwise, try to translate it from ASCII, extended keypad
 * values, and/or escape sequences.  Set meta_key to TRUE when we get a
 * meta sequence.  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-F14), and the numeric keypad with NumLock off.
 * Assume nodelay(win) is FALSE. */
int get_kbinput(WINDOW *win, int *meta_key)
{
    int kbinput, es, retval = ERR;

#ifndef NANO_SMALL
    allow_pending_sigwinch(TRUE);
#endif

    *meta_key = FALSE;

    while (retval == ERR) {
	/* Read a character using blocking input, since using
	 * non-blocking input will eat up all unused CPU.  Then pass it
	 * to get_translated_kbinput().  Continue until we get a
	 * complete sequence. */
	kbinput = wgetch(win);
	retval = get_translated_kbinput(kbinput, &es
#ifndef NANO_SMALL
		, FALSE
#endif
		);

	/* If we got an escape sequence, read it in, including the
	 * initial non-escape, as verbatim input. */
	if (es) {
	    int *escape_seq = NULL;
	    size_t es_len;

	    /* First, assume that we got a meta sequence.  Set meta_key
	     * to TRUE and save the character we got as the result.  We
	     * do this so that if the keyboard buffer is full when we
	     * send back the character we got below (in which case we'll
	     * lose that character), it'll still be properly interpreted
	     * as a meta sequence. */
	    *meta_key = TRUE;
	    retval = tolower(kbinput);

	    /* Next, send back the character we got and read in the
	     * complete escape sequence. */
	    ungetch(kbinput);
	    escape_seq = get_verbatim_kbinput(win, escape_seq, &es_len,
		FALSE);

	    /* If the escape sequence is more than one character
	     * long, set meta_key to FALSE, translate the escape
	     * sequence into the corresponding key value, and save
	     * that as the result. */
	    if (es_len > 1) {
		int ignore_seq;

		*meta_key = FALSE;
		retval = get_escape_seq_kbinput(escape_seq, es_len,
			&ignore_seq);

		if (retval == ERR && !ignore_seq) {
		    /* This escape sequence is unrecognized.  Send it
		     * back. */
		    for (; es_len > 1; es_len--)
			ungetch(escape_seq[es_len - 1]);
		    retval = escape_seq[0];
		}
	    }
	    free(escape_seq);
	}
    }

#ifdef DEBUG
    fprintf(stderr, "get_kbinput(): kbinput = %d, meta_key = %d\n", kbinput, *meta_key);
#endif

#ifndef NANO_SMALL
    allow_pending_sigwinch(FALSE);
#endif

    return retval;
}

/* Translate acceptable ASCII, extended keypad values, and escape
 * sequences into their corresponding key values.  Set es to TRUE when
 * we get an escape sequence.  Assume nodelay(win) is FALSE. */
int get_translated_kbinput(int kbinput, int *es
#ifndef NANO_SMALL
	, int reset
#endif
	)
{
    static size_t escapes = 0, ascii_digits = 0;
    int retval = ERR;

#ifndef NANO_SMALL
    if (reset) {
	escapes = 0;
	ascii_digits = 0;
	return ERR;
    }
#endif

    *es = FALSE;

    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. */
		    break;
		default:
		    /* More than two escapes: reset the escape counter
		     * and wait for more input. */
		    escapes = 0;
	    }
	    break;
#if !defined(NANO_SMALL) && defined(KEY_RESIZE)
	/* Since we don't change the default SIGWINCH handler when
	 * NANO_SMALL is defined, KEY_RESIZE is never generated.  Also,
	 * Slang and SunOS 5.7-5.9 don't support KEY_RESIZE. */
	case KEY_RESIZE:
	    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:
	    break;
#endif
	default:
	    switch (escapes) {
		case 0:
		    switch (kbinput) {
			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 and 11 don'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. */
			    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. */
			    break;
#endif
#ifdef KEY_END
			/* HP-UX 10 and 11 don't support KEY_END. */
			case KEY_END:
			    retval = NANO_END_KEY;
			    break;
#endif
#ifdef KEY_SUSPEND
			/* Slang doesn't support KEY_SUSPEND. */
			case KEY_SUSPEND:
			    retval = NANO_SUSPEND_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
			default:
			    retval = kbinput;
			    break;
		    }
		    break;
		case 1:
		    /* One escape followed by a non-escape: escape
		     * sequence mode.  Reset the escape counter and set
		     * es to TRUE. */
		    escapes = 0;
		    *es = TRUE;
		    break;
		case 2:
		    switch (kbinput) {
			case '0':
			case '1':
			case '2':
			case '3':
			case '4':
			case '5':
			case '6':
			case '7':
			case '8':
			case '9':
			    /* Two escapes followed by one or more
			     * digits: ASCII character sequence mode.
			     * If the digit sequence's range is limited
			     * to 2XX (the first digit is in the '0' to
			     * '2' range and it's the first digit, or if
			     * it's in the full digit range and it's not
			     * the first digit), increment the ASCII
			     * digit counter and interpret the digit.
			     * If the digit sequence's range is not
			     * limited to 2XX, fall through. */
			    if (kbinput <= '2' || ascii_digits > 0) {
				ascii_digits++;
				kbinput = get_ascii_kbinput(kbinput,
					ascii_digits
#ifndef NANO_SMALL
					, FALSE
#endif
					);

				if (kbinput != ERR) {
				    /* If we've read in a complete ASCII
				     * digit sequence, reset the ASCII
				     * digit counter and the escape
				     * counter and save the corresponding
				     * ASCII character as the result. */
				    ascii_digits = 0;
				    escapes = 0;
				    retval = kbinput;
				}
			    }
			    break;
			default:
			    /* Reset the escape counter. */
			    escapes = 0;
			    if (ascii_digits == 0)
				/* Two escapes followed by a non-digit
				 * or a digit that would create an ASCII
				 * digit sequence greater than 2XX, and
				 * we're not in the middle of an ASCII
				 * character sequence: 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 were in the middle of an ASCII
				 * character sequence, reset the ASCII
				 * digit counter and save the character
				 * we got as the result. */
				ascii_digits = 0;
				retval = kbinput;
			    }
		    }
	    }
    }

#ifdef DEBUG
    fprintf(stderr, "get_translated_kbinput(): kbinput = %d, es = %d, escapes = %d, ascii_digits = %d, retval = %d\n", kbinput, *es, escapes, ascii_digits, retval);
#endif

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

/* Translate an ASCII character sequence: turn a three-digit decimal
 * ASCII code from 000-255 into its corresponding ASCII character. */
int get_ascii_kbinput(int kbinput, size_t ascii_digits
#ifndef NANO_SMALL
	, int reset
#endif
	)
{
    static int ascii_kbinput = 0;
    int retval = ERR;

#ifndef NANO_SMALL
    if (reset) {
	ascii_kbinput = 0;
	return ERR;
    }
#endif

    switch (ascii_digits) {
	case 1:
	    /* Read in the first of the three ASCII digits. */
	    switch (kbinput) {
		/* Add the digit we got to the 100's position of the
		 * ASCII character sequence holder. */
		case '0':
		case '1':
		case '2':
		    ascii_kbinput += (kbinput - '0') * 100;
		    break;
		default:
		    retval = kbinput;
    	    }
	    break;
	case 2:
	    /* Read in the second of the three ASCII digits. */
	    switch (kbinput) {
		/* Add the digit we got to the 10's position of the
		 * ASCII character sequence holder. */
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		    ascii_kbinput += (kbinput - '0') * 10;
		    break;
		case '6':
		case '7':
		case '8':
		case '9':
		    if (ascii_kbinput < 200) {
			ascii_kbinput += (kbinput - '0') * 10;
			break;
		    }
		default:
		    retval = kbinput;
	    }
	    break;
	case 3:
	    /* Read in the third of the three ASCII digits. */
	    switch (kbinput) {
		/* Add the digit we got to the 1's position of the ASCII
		 * character sequence holder, and save the corresponding
		 * ASCII character as the result. */
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		    ascii_kbinput += (kbinput - '0');
		    retval = ascii_kbinput;
		    break;
		case '6':
		case '7':
		case '8':
		case '9':
		    if (ascii_kbinput < 250) {
			ascii_kbinput += (kbinput - '0');
			retval = ascii_kbinput;
			break;
		    }
		default:
		    retval = kbinput;
	    }
	    break;
    }

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

    /* If the result is an ASCII character, reset the ASCII character
     * sequence holder. */
    if (retval != ERR)
	ascii_kbinput = 0;

    return retval;
}

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

    /* We don't handle Ctrl-2 here, since Esc Esc 2 could be the first
     * part of an ASCII character sequence. */

     /* Ctrl-2 (Ctrl-Space) == Ctrl-@ == Ctrl-` */
    if (kbinput == ' ' || kbinput == '@' || kbinput == '`')
	retval = NANO_CONTROL_SPACE;
    /* Ctrl-3 (Ctrl-[, Esc) to Ctrl-7 (Ctrl-_) */
    else if (kbinput >= '3' && kbinput <= '7')
	retval = kbinput - 24;
    /* Ctrl-8 (Ctrl-?) */
    else if (kbinput == '8' || kbinput == '?')
	retval = NANO_CONTROL_8;
    /* Ctrl-A to Ctrl-_ */
    else if (kbinput >= 'A' && kbinput <= '_')
	retval = kbinput - 64;
    /* Ctrl-a to Ctrl-~ */
    else if (kbinput >= 'a' && kbinput <= '~')
	retval = kbinput - 96;
    else
	retval = kbinput;

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

    return retval;
}

/* Translate escape sequences, most of which correspond to extended
 * keypad values, nto their corresponding key values.  These sequences
 * are generated when the keypad doesn't support the needed keys.  If
 * the escape sequence is recognized but we want to ignore it, return
 * ERR and set ignore_seq to TRUE; if it's unrecognized, return ERR and
 * set ignore_seq to FALSE.  Assume that Escape has already been read
 * in. */
int get_escape_seq_kbinput(int *escape_seq, size_t es_len, int
	*ignore_seq)
{
    int retval = ERR;

    *ignore_seq = FALSE;

    if (es_len > 1) {
	switch (escape_seq[0]) {
	    case 'O':
		switch (escape_seq[1]) {
		    case '2':
			if (es_len >= 3) {
			    switch (escape_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;
			    }
			}
			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(escape_seq[1]);
			break;
		    case 'E': /* Esc O E == Center (5) on numeric keypad
			       * with NumLock off on xterm. */
			*ignore_seq = TRUE;
			break;
		    case 'F': /* Esc O F == End on xterm. */
			retval = NANO_END_KEY;
			break;
		    case 'H': /* Esc O H == Home on xterm. */
			retval = NANO_HOME_KEY;
			break;
		    case 'M': /* Esc O M == Enter on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * Eterm. */
			retval = NANO_ENTER_KEY;
			break;
		    case 'P': /* Esc O P == F1 on VT100/VT220/VT320/Hurd
			       * console. */
			retval = KEY_F(1);
			break;
		    case 'Q': /* Esc O Q == F2 on VT100/VT220/VT320/Hurd
			       * console. */
			retval = KEY_F(2);
			break;
		    case 'R': /* Esc O R == F3 on VT100/VT220/VT320/Hurd
			       * console. */
			retval = KEY_F(3);
			break;
		    case 'S': /* Esc O S == F4 on VT100/VT220/VT320/Hurd
			       * console. */
			retval = KEY_F(4);
			break;
		    case 'T': /* Esc O T == F5 on Hurd console. */
			retval = KEY_F(5);
			break;
		    case 'U': /* Esc O U == F6 on Hurd console. */
			retval = KEY_F(6);
			break;
		    case 'V': /* Esc O V == F7 on Hurd console. */
			retval = KEY_F(7);
			break;
		    case 'W': /* Esc O W == F8 on Hurd console. */
			retval = KEY_F(8);
			break;
		    case 'X': /* Esc O X == F9 on Hurd console. */
			retval = KEY_F(9);
			break;
		    case 'Y': /* Esc O Y == F10 on Hurd 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(escape_seq[1]);
			break;
		    case 'j': /* Esc O j == '*' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt. */
			retval = '*';
			break;
		    case 'k': /* Esc O k == '+' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt. */
			retval = '+';
			break;
		    case 'l': /* Esc O l == ',' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt. */
			retval = '+';
			break;
		    case 'm': /* Esc O m == '-' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt. */
			retval = '-';
			break;
		    case 'n': /* Esc O n == Delete (.) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * xterm/rxvt. */
			retval = NANO_DELETE_KEY;
			break;
		    case 'o': /* Esc O o == '/' on numeric keypad with
			       * NumLock off on VT100/VT220/VT320/xterm/
			       * rxvt. */
			retval = '/';
			break;
		    case 'p': /* Esc O p == Insert (0) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_INSERTFILE_KEY;
			break;
		    case 'q': /* Esc O q == End (1) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_END_KEY;
			break;
		    case 'r': /* Esc O r == Down (2) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_NEXTLINE_KEY;
			break;
		    case 's': /* Esc O s == PageDown (3) on numeric
			       * keypad with NumLock off on VT100/VT220/
			       * VT320/rxvt. */
			retval = NANO_NEXTPAGE_KEY;
			break;
		    case 't': /* Esc O t == Left (4) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_BACK_KEY;
			break;
		    case 'u': /* Esc O u == Center (5) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt/Eterm. */
			*ignore_seq = TRUE;
			break;
		    case 'v': /* Esc O v == Right (6) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_FORWARD_KEY;
			break;
		    case 'w': /* Esc O w == Home (7) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_HOME_KEY;
			break;
		    case 'x': /* Esc O x == Up (8) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_PREVLINE_KEY;
			break;
		    case 'y': /* Esc O y == PageUp (9) on numeric keypad
			       * with NumLock off on VT100/VT220/VT320/
			       * rxvt. */
			retval = NANO_PREVPAGE_KEY;
			break;
		}
		break;
	    case 'o':
		switch (escape_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(escape_seq[1]);
			break;
		}
		break;
	    case '[':
		switch (escape_seq[1]) {
		    case '1':
			if (es_len >= 3) {
			    switch (escape_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 (es_len >= 4) {
	switch (escape_seq[3]) {
	    case '2':
		if (es_len >= 5) {
		    switch (escape_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(escape_seq[4]);
			    break;
		    }
		}
		break;
	    case '5':
		if (es_len >= 5) {
		    switch (escape_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(escape_seq[4]);
			    break;
		    }
		}
		break;
	}
    }
				    break;
				default: /* Esc [ 1 ~ == Home on
					  * VT320/Linux console. */
				    retval = NANO_HOME_KEY;
				    break;
			    }
			}
			break;
		    case '2':
			if (es_len >= 3) {
			    switch (escape_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;
				default: /* Esc [ 2 ~ == Insert on
					  * VT220/VT320/Linux console/
					  * xterm. */
				    retval = NANO_INSERTFILE_KEY;
				    break;
			    }
			}
			break;
		    case '3': /* Esc [ 3 ~ == Delete on VT220/VT320/
			       * Linux console/xterm. */
			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; Esc [ 5 ^ ==
			       * PageUp on Eterm. */
			retval = NANO_PREVPAGE_KEY;
			break;
		    case '6': /* Esc [ 6 ~ == PageDown on VT220/VT320/
			       * Linux console/xterm; 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 Hurd console. */
			retval = NANO_DELETE_KEY;
			break;
		    case '@': /* Esc [ @ == Insert on Hurd console. */
			retval = NANO_INSERTFILE_KEY;
			break;
		    case 'A': /* Esc [ A == Up on ANSI/VT220/Linux
			       * console/FreeBSD console/Hurd console/
			       * rxvt/Eterm. */
		    case 'B': /* Esc [ B == Down on ANSI/VT220/Linux
			       * console/FreeBSD console/Hurd console/
			       * rxvt/Eterm. */
		    case 'C': /* Esc [ C == Right on ANSI/VT220/Linux
			       * console/FreeBSD console/Hurd console/
			       * rxvt/Eterm. */
		    case 'D': /* Esc [ D == Left on ANSI/VT220/Linux
			       * console/FreeBSD console/Hurd console/
			       * rxvt/Eterm. */
			retval = get_escape_seq_abcd(escape_seq[1]);
			break;
		    case 'E': /* Esc [ E == Center (5) on numeric keypad
			       * with NumLock off on FreeBSD console. */
			*ignore_seq = TRUE;
			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/Hurd 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 (es_len >= 3) {
			    switch (escape_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 Hurd console. */
			retval = NANO_NEXTPAGE_KEY;
			break;
		    case 'V': /* Esc [ V == PageUp on Hurd 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 Hurd 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(escape_seq[1]);
			break;
		    case '[':
			if (es_len >= 3) {
			    switch (escape_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, ignore_seq = %d\n", retval, *ignore_seq);
#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;
    }
}

/* Read in a string of input characters (e.g. an escape sequence)
 * verbatim.  Store the string in v_kbinput and return the length
 * of the string in v_len.  Assume nodelay(win) is FALSE. */
int *get_verbatim_kbinput(WINDOW *win, int *v_kbinput, size_t
	*v_len, int allow_ascii)
{
    int kbinput;
    size_t i = 0, v_newlen = 0;

#ifndef NANO_SMALL
    allow_pending_sigwinch(TRUE);
#endif

    *v_len = 0;
    v_kbinput = (int *)nmalloc(sizeof(int));

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

    /* Read the first character using blocking input, since using
     * non-blocking input will eat up all unused CPU.  Then increment
     * v_len and save the character in v_kbinput. */
    kbinput = wgetch(win);
    (*v_len)++;
    v_kbinput[0] = kbinput;
#ifdef DEBUG
    fprintf(stderr, "get_verbatim_kbinput(): kbinput = %d, v_len = %d\n", kbinput, *v_len);
#endif

    /* Read any following characters using non-blocking input, until
     * there aren't any left to be read, and save the complete string of
     * characters in v_kbinput, incrementing v_len accordingly.  We read
     * them all at once in order to minimize the chance that there might
     * be a delay greater than nodelay() provides for between them, in
     * which case we'll stop before all of them are read. */
    nodelay(win, TRUE);
    while ((kbinput = wgetch(win)) != ERR) {
	(*v_len)++;
	v_kbinput = (int *)nrealloc(v_kbinput, *v_len * sizeof(int));
	v_kbinput[*v_len - 1] = kbinput;
#ifdef DEBUG
	fprintf(stderr, "get_verbatim_kbinput(): kbinput = %d, v_len = %d\n", kbinput, *v_len);
#endif
    }
    nodelay(win, FALSE);

    /* Pass the string of characters to get_untranslated_kbinput(), one
     * by one, so it can handle them as ASCII character sequences and/or
     * escape sequences.  Filter out ERR's from v_kbinput in the
     * process; they shouldn't occur in the string of characters unless
     * we're reading an incomplete sequence, in which case we only want
     * to keep the complete sequence. */
    for (; i < *v_len; i++) {
	v_kbinput[v_newlen] = get_untranslated_kbinput(v_kbinput[i], i,
		allow_ascii
#ifndef NANO_SMALL
		, FALSE
#endif
		);
	if (v_kbinput[i] != ERR && v_kbinput[v_newlen] != ERR)
	    v_newlen++;
    }

    if (v_newlen == 0) {
	/* If there were no characters after the ERR's were filtered
	 * out, set v_len and reallocate v_kbinput to account for
	 * one character, and set that character to ERR. */
	*v_len = 1;
	v_kbinput = (int *)nrealloc(v_kbinput, sizeof(int));
	v_kbinput[0] = ERR;
    } else if (v_newlen != *v_len) {
	/* If there were fewer characters after the ERR's were filtered
	 * out, set v_len and reallocate v_kbinput to account for
	 * the new number of characters. */
	*v_len = v_newlen;
	v_kbinput = (int *)nrealloc(v_kbinput, *v_len * sizeof(int));
    }

    /* If allow_ascii is TRUE and v_kbinput[0] is ERR, we need to
     * complete an ASCII character sequence.  Keep reading in characters
     * using blocking input until we get a complete sequence. */
    if (allow_ascii && v_kbinput[0] == ERR) {
	while (v_kbinput[0] == ERR) {
	    kbinput = wgetch(win);
	    v_kbinput[0] = get_untranslated_kbinput(kbinput, i,
		allow_ascii
#ifndef NANO_SMALL
		, FALSE
#endif
		);
	    i++;
	}
    }

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

#ifndef NANO_SMALL
    allow_pending_sigwinch(FALSE);
#endif

    return v_kbinput;
}

int get_untranslated_kbinput(int kbinput, size_t position, int
	allow_ascii
#ifndef NANO_SMALL
	, int reset
#endif
	)
{
    static size_t ascii_digits = 0;
    int retval;

#ifndef NANO_SMALL
    if (reset) {
	ascii_digits = 0;
	return ERR;
    }
#endif

    if (allow_ascii) {
	/* position is equal to the number of ASCII digits we've read so
	 * far, and kbinput is a digit from '0' to '9': ASCII character
	 * sequence mode.  If the digit sequence's range is limited to
	 * 2XX (the first digit is in the '0' to '2' range and it's the
	 * first digit, or if it's in the full digit range and it's not
	 * the first digit), increment the ASCII digit counter and
	 * interpret the digit.  If the digit sequence's range is not
	 * limited to 2XX, fall through. */
	if (position == ascii_digits && kbinput >= '0' && kbinput <= '9') {
	    if (kbinput <= '2' || ascii_digits > 0) {
		ascii_digits++;
		kbinput = get_ascii_kbinput(kbinput, ascii_digits
#ifndef NANO_SMALL
			, FALSE
#endif
			);
		if (kbinput != ERR)
		    /* If we've read in a complete ASCII digit sequence,
		     * reset the ASCII digit counter. */
		    ascii_digits = 0;
	    }
	} else if (ascii_digits > 0)
	    /* position is not equal to the number of ASCII digits we've
	     * read or kbinput is a non-digit, and we're in the middle
	     * of an ASCII character sequence.  Reset the ASCII digit
	     * counter. */
	    ascii_digits = 0;
    }

    /* Save the corresponding ASCII character as the result if we've
     * read in a complete ASCII digit sequence, or the passed-in
     * character if we haven't. */
     retval = kbinput;

#ifdef DEBUG
    fprintf(stderr, "get_untranslated_kbinput(): kbinput = %d, position = %d, ascii_digits = %d\n", kbinput, position, ascii_digits);
#endif

    return retval;
}

#ifndef DISABLE_MOUSE
/* Check for a mouse event, and if one's taken place, save the
 * coordinates where it took place in mouse_x and mouse_y.  After that,
 * if allow_shortcuts is zero, return 0.  Otherwise, if the mouse event
 * took place on the shortcut list on the bottom two lines of the screen
 * (assuming that the shortcut list is visible), figure out which
 * shortcut was clicked and ungetch() the equivalent keystroke(s).
 * Return 0 if no keystrokes were ungetch()ed, or 1 if at least one was.
 * Assume that KEY_MOUSE has already been read in. */
int get_mouseinput(int *mouse_x, int *mouse_y, int allow_shortcuts)
{
    MEVENT mevent;

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

    /* First, get the actual mouse event. */
    if (getmouse(&mevent) == ERR)
	return 0;

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

    /* If we're not allowing shortcuts' we're done now. */
    if (!allow_shortcuts)
	return 0;

    /* Otherwise, if the current shortcut list is being displayed on the
     * last two lines of the screen and the mouse event took place
     * inside it, we need to figure out which shortcut was clicked and
     * ungetch() the equivalent keystroke(s) for it. */
    if (!ISSET(NO_HELP) && wenclose(bottomwin, *mouse_y, *mouse_x)) {
	int i, j;
	int currslen;
	    /* The number of shortcuts in the current shortcut list. */
	const shortcut *s = currshortcut;
	    /* The actual shortcut we clicked on, starting at the first
	     * one in the current shortcut list. */

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

	/* Calculate the width of each shortcut in the list (it's the
	 * same for all of them). */
	if (currslen < 2)
	    i = COLS / 6;
	else
	    i = COLS / ((currslen / 2) + (currslen % 2));

	/* Calculate the y-coordinates relative to the beginning of
	 * bottomwin, i.e, the bottom three lines of the screen. */
	j = *mouse_y - (editwinrows + 3);

	/* If we're on the statusbar, beyond the end of the shortcut
	 * list, or beyond the end of a shortcut on the right side of
	 * the screen, don't do anything. */
	if (j < 0 || (*mouse_x / i) >= currslen)
	    return 0;
	j = (*mouse_x / i) * 2 + j;
	if (j >= currslen)
	    return 0;

	/* Go through the shortcut list to determine which shortcut was
	 * clicked. */
	for (; j > 0; j--)
	    s = s->next;

	/* And ungetch() the equivalent control key.  If it's a meta key
	 * sequence, we need to ungetch() Escape too.  Assume that the
	 * shortcut has an equivalent control key, meta key sequence, or
	 * both. */
	if (s->ctrlval != NANO_NO_KEY)
	    ungetch(s->ctrlval);
	else if (s->ctrlval != NANO_NO_KEY) {
	    ungetch(s->metaval);
	    ungetch(NANO_CONTROL_3);
	}

	return 1;
    }
    return 0;
}
#endif

/* Return the placewewant associated with current_x.  That is, xplustabs
 * is the zero-based column position of the cursor.  Value is no smaller
 * than current_x. */
size_t xplustabs(void)
{
    return strnlenpt(current->data, current_x);
}

/* actual_x() gives the index in str of the character displayed at
 * column xplus.  That is, actual_x() is the largest value such that
 * strnlenpt(str, actual_x(str, xplus)) <= xplus. */
size_t actual_x(const char *str, size_t xplus)
{
    size_t i = 0;
	/* the position in str, returned */
    size_t length = 0;
	/* the screen display width to str[i] */

    assert(str != NULL);

    for (; length < xplus && *str != '\0'; i++, str++) {
	if (*str == '\t')
	    length += tabsize - (length % tabsize);
	else if (is_cntrl_char((int)*str))
	    length += 2;
	else
	    length++;
    }
    assert(length == strnlenpt(str - i, i));
    assert(i <= strlen(str - i));

    if (length > xplus)
	i--;

    return i;
}

/* A strlen() with tabs factored in, similar to xplustabs().  How many
 * columns wide are the first size characters of buf? */
size_t strnlenpt(const char *buf, size_t size)
{
    size_t length = 0;

    assert(buf != NULL);
    for (; *buf != '\0' && size != 0; size--, buf++) {
	if (*buf == '\t')
	    length += tabsize - (length % tabsize);
	else if (is_cntrl_char((int)*buf))
	    length += 2;
	else
	    length++;
    }
    return length;
}

/* How many columns wide is buf? */
size_t strlenpt(const char *buf)
{
    return strnlenpt(buf, (size_t)-1);
}

void blank_titlebar(void)
{
    mvwaddstr(topwin, 0, 0, hblank);
}

void blank_edit(void)
{
    size_t i;
    for (i = 0; i < editwinrows; i++)
	mvwaddstr(edit, i, 0, hblank);
}

void blank_statusbar(void)
{
    mvwaddstr(bottomwin, 0, 0, hblank);
}

void check_statblank(void)
{
    if (statblank > 1)
	statblank--;
    else if (statblank == 1 && !ISSET(CONSTUPDATE)) {
	statblank = 0;
	blank_statusbar();
	wnoutrefresh(bottomwin);
	reset_cursor();
	wrefresh(edit);
    }
}

void blank_bottombars(void)
{
    if (!ISSET(NO_HELP)) {
	mvwaddstr(bottomwin, 1, 0, hblank);
	mvwaddstr(bottomwin, 2, 0, hblank);
    }
}

/* 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. */
char *display_string(const char *buf, size_t start_col, size_t len)
{
    size_t start_index;
	/* Index in buf of first character shown in return value. */
    size_t column;
	/* Screen column start_index corresponds to. */
    size_t end_index;
	/* Index in buf of last character shown in return value. */
    size_t alloc_len;
	/* The length of memory allocated for converted. */
    char *converted;
	/* The string we return. */
    size_t index;
	/* Current position in converted. */

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

    start_index = actual_x(buf, start_col);
    column = strnlenpt(buf, start_index);
    assert(column <= start_col);
    end_index = actual_x(buf, start_col + len - 1);
    alloc_len = strnlenpt(buf, end_index + 1) - column;
    if (len > alloc_len + column - start_col)
	len = alloc_len + column - start_col;
    converted = charalloc(alloc_len + 1);
    buf += start_index;
    index = 0;

    for (; index < alloc_len; buf++) {
	if (*buf == '\t') {
	    converted[index++] =
#if !defined(NANO_SMALL) && defined(ENABLE_NANORC)
		ISSET(WHITESPACE_DISPLAY) ? whitespace[0] :
#endif
		' '; 
	    while ((column + index) % tabsize)
		converted[index++] = ' ';
	} else if (is_cntrl_char(*buf)) {
	    converted[index++] = '^';
	    if (*buf == '\n')
		/* Treat newlines embedded in a line as encoded nulls;
		 * the line in question should be run through unsunder()
		 * before reaching here. */
		converted[index++] = '@';
	    else if (*buf == NANO_CONTROL_8)
		converted[index++] = '?';
	    else
		converted[index++] = *buf + 64;
	} else if (*buf == ' ')
	    converted[index++] =
#if !defined(NANO_SMALL) && defined(ENABLE_NANORC)
		ISSET(WHITESPACE_DISPLAY) ? whitespace[1] :
#endif
		' ';
	else
	    converted[index++] = *buf;
    }
    assert(len <= alloc_len + column - start_col);
    charmove(converted, converted + start_col - column, len);
    null_at(&converted, len);

    return charealloc(converted, len + 1);
}

/* Repaint the statusbar when getting a character in nanogetstr().  buf
 * should be no longer than max(0, COLS - 4).
 *
 * Note that we must turn on A_REVERSE here, since do_help() turns it
 * off! */
void nanoget_repaint(const char *buf, const char *inputbuf, size_t x)
{
    size_t x_real = strnlenpt(inputbuf, x);
    int wid = COLS - strlen(buf) - 2;

    assert(0 <= x && x <= strlen(inputbuf));

    wattron(bottomwin, A_REVERSE);
    blank_statusbar();

    mvwaddstr(bottomwin, 0, 0, buf);
    waddch(bottomwin, ':');

    if (COLS > 1)
	waddch(bottomwin, x_real < wid ? ' ' : '$');
    if (COLS > 2) {
	size_t page_start = x_real - x_real % wid;
	char *expanded = display_string(inputbuf, page_start, wid);

	assert(wid > 0);
	assert(strlen(expanded) <= wid);
	waddstr(bottomwin, expanded);
	free(expanded);
	wmove(bottomwin, 0, COLS - wid + x_real - page_start);
    } else
	wmove(bottomwin, 0, COLS - 1);
    wattroff(bottomwin, A_REVERSE);
}

/* Get the input from the keyboard; this should only be called from
 * statusq(). */
int nanogetstr(int allowtabs, const char *buf, const char *def,
#ifndef NANO_SMALL
		historyheadtype *history_list,
#endif
		const shortcut *s
#ifndef DISABLE_TABCOMP
		, int *list
#endif
		)
{
    int kbinput;
    int meta_key;
    static int x = -1;
	/* the cursor position in 'answer' */
    int xend;
	/* length of 'answer', the status bar text */
    int tabbed = 0;
	/* used by input_tab() */
    const shortcut *t;

#ifndef NANO_SMALL
   /* for history */
    char *history = NULL;
    char *currentbuf = NULL;
    char *complete = NULL;
    int last_kbinput = 0;

    /* This variable is used in the search history code.  use_cb == 0 
       means that we're using the existing history and ignoring
       currentbuf.  use_cb == 1 means that the entry in answer should be
       moved to currentbuf or restored from currentbuf to answer. 
       use_cb == 2 means that the entry in currentbuf should be moved to
       answer or restored from answer to currentbuf. */
    int use_cb = 0;
#endif
    xend = strlen(def);

    /* Only put x at the end of the string if it's uninitialized or if
       it would be past the end of the string as it is.  Otherwise,
       leave it alone.  This is so the cursor position stays at the same
       place if a prompt-changing toggle is pressed. */
    if (x == -1 || x > xend || resetstatuspos)
	x = xend;

    answer = charealloc(answer, xend + 1);
    if (xend > 0)
	strcpy(answer, def);
    else
	answer[0] = '\0';

#if !defined(DISABLE_HELP) || !defined(DISABLE_MOUSE)
    currshortcut = s;
#endif

    /* Get the input! */

    nanoget_repaint(buf, answer, x);

    /* Make sure any editor screen updates are displayed before getting
       input */
    wrefresh(edit);

    /* If we're using restricted mode, we aren't allowed to change the
     * name of a file once it has one because that would allow writing
     * to files not specified on the command line.  In this case,
     * disable all keys that would change the text if the filename isn't
     * blank and we're at the "Write File" prompt. */
    while ((kbinput = get_kbinput(bottomwin, &meta_key)) != NANO_ENTER_KEY) {
	for (t = s; t != NULL; t = t->next) {
#ifdef DEBUG
	    fprintf(stderr, "Aha! \'%c\' (%d)\n", kbinput, kbinput);
#endif

	    /* Temporary hack to interpret NANO_HELP_FKEY correctly. */
	    if (kbinput == t->funcval)
		kbinput = t->ctrlval;

	    if (kbinput == t->ctrlval && is_cntrl_char(kbinput)) {

#ifndef DISABLE_HELP
		/* Have to do this here, it would be too late to do it
		   in statusq() */
		if (kbinput == NANO_HELP_KEY) {
		    do_help();
		    break;
		}
#endif
#ifndef NANO_SMALL
		/* Have to handle these here too, for the time being */
		if (kbinput == NANO_PREVLINE_KEY || kbinput == NANO_NEXTLINE_KEY)
		    break;
#endif

		return t->ctrlval;
	    }
	}
	assert(0 <= x && x <= xend && xend == strlen(answer));

	if (kbinput != '\t')
	    tabbed = 0;

	switch (kbinput) {
#ifndef DISABLE_MOUSE
	case KEY_MOUSE:
	    do_mouse();
	    break;
#endif
	case NANO_HOME_KEY:
#ifndef NANO_SMALL
	    if (ISSET(SMART_HOME)) {
		int old_x = x;

		for (x = 0; isblank(answer[x]) && x < xend; x++)
		    ;

		if (x == old_x || x == xend)
		    x = 0;
	    } else
#endif
		x = 0;
	    break;
	case NANO_END_KEY:
	    x = xend;
	    break;
	case NANO_FORWARD_KEY:
	    if (x < xend)
		x++;
	    break;
	case NANO_DELETE_KEY:
	    /* If we're using restricted mode, the filename isn't blank,
	     * and we're at the "Write File" prompt, disable Delete. */
	    if (!ISSET(RESTRICTED) || filename[0] == '\0' || s != writefile_list) {
		if (x < xend) {
		    charmove(answer + x, answer + x + 1, xend - x);
		    xend--;
		}
	    }
	    break;
	case NANO_CUT_KEY:
	case NANO_UNCUT_KEY:
	    /* If we're using restricted mode, the filename isn't blank,
	     * and we're at the "Write File" prompt, disable Cut and
	     * UnCut. */
	    if (!ISSET(RESTRICTED) || filename[0] == '\0' || s != writefile_list) {
		null_at(&answer, 0);
		xend = 0;
		x = 0;
	    }
	    break;
	case NANO_BACKSPACE_KEY:
	    /* If we're using restricted mode, the filename isn't blank,
	     * and we're at the "Write File" prompt, disable
	     * Backspace. */
	    if (!ISSET(RESTRICTED) || filename[0] == '\0' || s != writefile_list) {
		if (x > 0) {
		    charmove(answer + x - 1, answer + x, xend - x + 1);
		    x--;
		    xend--;
		}
	    }
	    break;
	case NANO_TAB_KEY:
#ifndef NANO_SMALL
	    /* tab history completion */
	    if (history_list != NULL) {
		if (!complete || last_kbinput != NANO_TAB_KEY) {
		    history_list->current = (historytype *)history_list;
		    history_list->len = strlen(answer);
		}

		if (history_list->len > 0) {
		    complete = get_history_completion(history_list, answer);
		    xend = strlen(complete);
		    x = xend;
		    answer = mallocstrcpy(answer, complete);
		}
	    }
#ifndef DISABLE_TABCOMP
	    else
#endif
#endif
#ifndef DISABLE_TABCOMP
	    if (allowtabs) {
		int shift = 0;

		answer = input_tab(answer, x, &tabbed, &shift, list);
		xend = strlen(answer);
		x += shift;
		if (x > xend)
		    x = xend;
	    }
#endif
	    break;
	case NANO_BACK_KEY:
	    if (x > 0)
		x--;
	    break;
	case NANO_PREVLINE_KEY:
#ifndef NANO_SMALL
	    if (history_list != NULL) {

		/* if currentbuf is NULL, or if use_cb is 1, currentbuf
		   isn't NULL, and currentbuf is different from answer,
		   it means that we're scrolling up at the top of the
		   search history, and we need to save the current
		   answer in currentbuf; do this and reset use_cb to
		   0 */
		if (currentbuf == NULL || (use_cb == 1 && strcmp(currentbuf, answer))) {
		    currentbuf = mallocstrcpy(currentbuf, answer);
		    use_cb = 0;
		}

		/* if currentbuf isn't NULL, use_cb is 2, and currentbuf 
		   is different from answer, it means that we're
		   scrolling up at the bottom of the search history, and
		   we need to make the string in currentbuf the current
		   answer; do this, blow away currentbuf since we don't
		   need it anymore, and reset use_cb to 0 */
		if (currentbuf != NULL && use_cb == 2 && strcmp(currentbuf, answer)) {
		    answer = mallocstrcpy(answer, currentbuf);
		    free(currentbuf);
		    currentbuf = NULL;
		    xend = strlen(answer);
		    use_cb = 0;

		/* else get older search from the history list and save
		   it in answer; if there is no older search, blank out 
		   answer */
		} else if ((history = get_history_older(history_list)) != NULL) {
		    answer = mallocstrcpy(answer, history);
		    xend = strlen(history);
		} else {
		    answer = mallocstrcpy(answer, "");
		    xend = 0;
		}
		x = xend;
	    }
#endif
	    break;
	case NANO_NEXTLINE_KEY:
#ifndef NANO_SMALL
	    if (history_list != NULL) {

		/* get newer search from the history list and save it 
		   in answer */
		if ((history = get_history_newer(history_list)) != NULL) {
		    answer = mallocstrcpy(answer, history);
		    xend = strlen(history);

		/* if there is no newer search, we're here */
		
		/* if currentbuf isn't NULL and use_cb isn't 2, it means 
		   that we're scrolling down at the bottom of the search
		   history and we need to make the string in currentbuf
		   the current answer; do this, blow away currentbuf
		   since we don't need it anymore, and set use_cb to
		   1 */
		} else if (currentbuf != NULL && use_cb != 2) {
		    answer = mallocstrcpy(answer, currentbuf);
		    free(currentbuf);
		    currentbuf = NULL;
		    xend = strlen(answer);
		    use_cb = 1;

		/* otherwise, if currentbuf is NULL and use_cb isn't 2, 
		   it means that we're scrolling down at the bottom of
		   the search history and the current answer (if it's
		   not blank) needs to be saved in currentbuf; do this,
		   blank out answer (if necessary), and set use_cb to
		   2 */
		} else if (use_cb != 2) {
		    if (answer[0] != '\0') {
			currentbuf = mallocstrcpy(currentbuf, answer);
			answer = mallocstrcpy(answer, "");
		    }
		    xend = 0;
		    use_cb = 2;
		}
		x = xend;
	    }
#endif
	    break;
	    default:

		for (t = s; t != NULL; t = t->next) {
#ifdef DEBUG
		    fprintf(stderr, "Aha! \'%c\' (%d)\n", kbinput,
			    kbinput);
#endif
		    if (meta_key == TRUE && (kbinput == t->metaval || kbinput == t->miscval))
			/* We hit a meta key.  Do like above.  We don't
			 * just ungetch() the letter and let it get
			 * caught above cause that screws the
			 * keypad... */
			return kbinput;
		}

	    /* If we're using restricted mode, the filename isn't blank,
	     * and we're at the "Write File" prompt, act as though the
	     * unhandled character we got is a control character and
	     * throw it away. */
	    if (is_cntrl_char(kbinput) || (ISSET(RESTRICTED) && filename[0] != '\0' && s == writefile_list))
		break;
	    answer = charealloc(answer, xend + 2);
	    charmove(answer + x + 1, answer + x, xend - x + 1);
	    xend++;
	    answer[x] = kbinput;
	    x++;

#ifdef DEBUG
	    fprintf(stderr, "input \'%c\' (%d)\n", kbinput, kbinput);
#endif
	} /* switch (kbinput) */
#ifndef NANO_SMALL
	last_kbinput = kbinput;
#endif
	nanoget_repaint(buf, answer, x);
	wrefresh(bottomwin);
    } /* while (kbinput ...) */

    /* We finished putting in an answer; reset x */
    x = -1;

    /* Just check for a blank answer here */
    if (answer[0] == '\0')
	return -2;
    else
	return 0;
}

void titlebar(const char *path)
{
    size_t space;
	/* The space we have available for display. */
    size_t verlen = strlen(VERMSG) + 1;
	/* The length of the version message. */
    const char *prefix;
	/* "File:", "Dir:", or "New Buffer".  Goes before filename. */
    size_t prefixlen;
	/* strlen(prefix) + 1. */
    const char *state;
	/* "Modified", "View", or spaces the length of "Modified".
	 * Tells the state of this buffer. */
    size_t statelen = 0;
	/* strlen(state) + 1. */
    char *exppath = NULL;
	/* The file name, expanded for display. */
    size_t explen = 0;
	/* strlen(exppath) + 1. */
    int newbuffer = FALSE;
	/* Do we say "New Buffer"? */
    int dots = FALSE;
	/* Do we put an ellipsis before the path? */

    assert(path != NULL || filename != NULL);
    assert(COLS >= 0);

    wattron(topwin, A_REVERSE);

    blank_titlebar();

    if (COLS <= 5 || COLS - 5 < verlen)
	space = 0;
    else {
	space = COLS - 5 - verlen;
	/* Reserve 2/3 of the screen plus one column for after the
	 * version message. */
	if (space < COLS - (COLS / 3) + 1)
	    space = COLS - (COLS / 3) + 1;
    }

    if (COLS > 4) {
	/* The version message should only take up 1/3 of the screen
	 * minus one column. */
	mvwaddnstr(topwin, 0, 2, VERMSG, (COLS / 3) - 3);
	waddstr(topwin, "  ");
    }

    if (ISSET(MODIFIED))
	state = _("Modified");
    else if (path == NULL && ISSET(VIEW_MODE))
	state = _("View");
    else {
	if (space > 0)
	    statelen = strnlen(_("Modified"), space - 1) + 1;
	state = &hblank[COLS - statelen];
    }
    statelen = strnlen(state, COLS);
    /* We need a space before state. */
    if ((ISSET(MODIFIED) || ISSET(VIEW_MODE)) && statelen < COLS)
	statelen++;

    assert(space >= 0);
    if (space == 0 || statelen >= space)
	goto the_end;

#ifndef DISABLE_BROWSER
    if (path != NULL)
	prefix = _("DIR:");
    else
#endif
    if (filename[0] == '\0') {
	prefix = _("New Buffer");
	newbuffer = TRUE;
    } else
	prefix = _("File:");
    assert(statelen < space);
    prefixlen = strnlen(prefix, space - statelen);
    /* If newbuffer is FALSE, we need a space after prefix. */
    if (!newbuffer && prefixlen + statelen < space)
	prefixlen++;

    if (path == NULL)
	path = filename;
    space -= prefixlen + statelen;
	/* space is now the room we have for the file name. */
    if (!newbuffer) {
	size_t lenpt = strlenpt(path), start_col;

	if (lenpt > space)
	    start_col = actual_x(path, lenpt - space);
	else
	    start_col = 0;
	exppath = display_string(path, start_col, space);
	dots = (lenpt > space);
	explen = strlen(exppath);
    }

    if (!dots) {
	/* There is room for the whole filename, so we center it. */
	waddnstr(topwin, hblank, (space - explen) / 3);
	waddnstr(topwin, prefix, prefixlen);
	if (!newbuffer) {
	    assert(strlen(prefix) + 1 == prefixlen);
	    waddch(topwin, ' ');
	    waddstr(topwin, exppath);
	}
    } else {
	/* We will say something like "File: ...ename". */
	waddnstr(topwin, prefix, prefixlen);
	if (space <= 0 || newbuffer)
	    goto the_end;
	waddch(topwin, ' ');
	waddnstr(topwin, "...", space);
	if (space <= 3)
	    goto the_end;
	space -= 3;
	assert(explen = space + 3);
	waddnstr(topwin, exppath + 3, space);
    }

  the_end:

    free(exppath);

    if (COLS <= 1 || statelen >= COLS - 1)
	mvwaddnstr(topwin, 0, 0, state, COLS);
    else {
	assert(COLS - statelen - 2 >= 0);
	mvwaddch(topwin, 0, COLS - statelen - 2, ' ');
	mvwaddnstr(topwin, 0, COLS - statelen - 1, state, statelen);
    }

    wattroff(topwin, A_REVERSE);

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

/* If modified is not already set, set it and update titlebar. */
void set_modified(void)
{
    if (!ISSET(MODIFIED)) {
	SET(MODIFIED);
	titlebar(NULL);
    }
}

void statusbar(const char *msg, ...)
{
    va_list ap;

    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 (curses_ended) {
	vfprintf(stderr, msg, ap);
	va_end(ap);
	return;
    }

    /* Blank out the line. */
    blank_statusbar();

    if (COLS >= 4) {
	char *bar;
	char *foo;
	size_t start_x = 0, foo_len;
#if !defined(NANO_SMALL) && defined(ENABLE_NANORC)
	int old_whitespace = ISSET(WHITESPACE_DISPLAY);
	UNSET(WHITESPACE_DISPLAY);
#endif
	bar = charalloc(COLS - 3);
	vsnprintf(bar, COLS - 3, msg, ap);
	va_end(ap);
	foo = display_string(bar, 0, COLS - 4);
#if !defined(NANO_SMALL) && defined(ENABLE_NANORC)
	if (old_whitespace)
	    SET(WHITESPACE_DISPLAY);
#endif
	free(bar);
	foo_len = strlen(foo);
	start_x = (COLS - foo_len - 4) / 2;

	wmove(bottomwin, 0, start_x);
	wattron(bottomwin, A_REVERSE);

	waddstr(bottomwin, "[ ");
	waddstr(bottomwin, foo);
	free(foo);
	waddstr(bottomwin, " ]");
	wattroff(bottomwin, A_REVERSE);
	wnoutrefresh(bottomwin);
	reset_cursor();
	wrefresh(edit);
	    /* Leave the cursor at its position in the edit window, not
	     * in the statusbar. */
    }

    SET(DISABLE_CURPOS);
    statblank = 26;
}

void bottombars(const shortcut *s)
{
    size_t i, colwidth, slen;
    char *keystr;

    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.  We need at least
     * 3 to display anything properly.*/
    colwidth = COLS / ((slen / 2) + (slen % 2));
    keystr = charalloc(colwidth);

    blank_bottombars();

    for (i = 0; i < slen; i++, s = s->next) {
	wmove(bottomwin, 1 + i % 2, (i / 2) * colwidth);

	/* Yucky sentinel values we can't handle a better way. */
#ifndef NANO_SMALL
	if (s->ctrlval == NANO_HISTORY_KEY)
	    strncpy(keystr, _("Up"), colwidth);
	else
#endif
	if (s->ctrlval == NANO_CONTROL_SPACE)
	    strncpy(keystr, "^ ", colwidth);
	else if (s->ctrlval == NANO_CONTROL_8)
	    strncpy(keystr, "^?", colwidth);
	/* Normal values.  Assume that the shortcut has an equivalent
	 * control key, meta key sequence, or both. */
	else if (s->ctrlval != NANO_NO_KEY)
	    snprintf(keystr, colwidth, "^%c", s->ctrlval + 64);
	else if (s->metaval != NANO_NO_KEY)
	    snprintf(keystr, colwidth, "M-%c", toupper(s->metaval));

	onekey(keystr, s->desc, colwidth);
    }

    free(keystr);

    wnoutrefresh(bottomwin);
    reset_cursor();
    wrefresh(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)
{
    assert(keystroke != NULL && desc != NULL && len >= 0);
    wattron(bottomwin, A_REVERSE);
    waddnstr(bottomwin, keystroke, len);
    wattroff(bottomwin, A_REVERSE);
    len -= strlen(keystroke) + 1;
    if (len > 0) {
	waddch(bottomwin, ' ');
	waddnstr(bottomwin, desc, len);
    }
}

/* And so start the display update routines. */

#ifndef NDEBUG
int check_linenumbers(const filestruct *fileptr)
{
    int check_line = 0;
    const filestruct *filetmp;

    for (filetmp = edittop; filetmp != fileptr; filetmp = filetmp->next)
	check_line++;
    return check_line;
}
#endif

/* nano scrolls horizontally within a line in chunks.  This function
 * returns the column number of the first character displayed in the
 * window when the cursor is at the given column.  Note that
 * 0 <= column - get_page_start(column) < COLS. */
size_t get_page_start(size_t column)
{
    assert(COLS > 0);
    if (column == 0 || column < COLS - 1)
	return 0;
    else if (COLS > 9)
	return column - 7 - (column - 7) % (COLS - 8);
    else if (COLS > 2)
	return column - (COLS - 2);
    else
	return column - (COLS - 1);
		/* The parentheses are necessary to avoid overflow. */
}

/* Resets current_y, based on the position of current, and puts the
 * cursor at (current_y, current_x). */
void reset_cursor(void)
{
    /* Yuck.  This condition can be true after open_file() when opening
     * the first file. */
    if (edittop == NULL)
	return;

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

	wmove(edit, current_y, x - get_page_start(x));
     }
}

/* edit_add() takes care of the job of actually painting a line into the
 * edit window.  fileptr is the line to be painted, at row yval 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_add(const filestruct *fileptr, const char *converted, int
	yval, size_t start)
{
#if defined(ENABLE_COLOR) || !defined(NANO_SMALL)
    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(fileptr != NULL && converted != NULL);
    assert(strlen(converted) <= COLS);

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

#ifdef ENABLE_COLOR
    if (colorstrings != NULL && ISSET(COLOR_SYNTAX)) {
	const colortype *tmpcolor = 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. */
	    regmatch_t startmatch;	/* match position for start_regexp */
	    regmatch_t endmatch;	/* match position for end_regexp */

	    if (tmpcolor->bright)
		wattron(edit, A_BOLD);
	    wattron(edit, COLOR_PAIR(tmpcolor->pairnum));
	    /* Two notes about regexec().  Return value 0 means 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
		 * 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 0.  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;
		    if (startmatch.rm_so == startmatch.rm_eo) {
			startmatch.rm_eo++;
			statusbar(_("Refusing 0 length regex match"));
		    } else if (startmatch.rm_so < endpos &&
				startmatch.rm_eo > startpos) {
			if (startmatch.rm_so <= startpos)
			    x_start = 0;
			else
			    x_start = strnlenpt(fileptr->data,
				startmatch.rm_so) - start;
			paintlen = strnlenpt(fileptr->data,
				startmatch.rm_eo) - start - x_start;
			if (paintlen > COLS - x_start)
			    paintlen = COLS - x_start;

			assert(0 <= x_start && 0 < paintlen &&
				x_start + paintlen <= COLS);
			mvwaddnstr(edit, yval, x_start,
				converted + x_start, paintlen);
		    }
		    k = startmatch.rm_eo;
		}
	    } else {
		/* This is a multi-line regexp.  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;
		}
		/* 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))
		    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. */
		paintlen = end_line != fileptr ? COLS :
			strnlenpt(fileptr->data, endmatch.rm_eo) - start;
		if (paintlen > COLS)
		    paintlen = COLS;

		assert(0 < paintlen && paintlen <= COLS);
		mvwaddnstr(edit, yval, 0, converted, paintlen);

		/* We have already painted the whole line. */
		if (paintlen == COLS)
		    goto skip_step_two;

  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;

		    if (startmatch.rm_so <= startpos)
			x_start = 0;
		    else
			x_start = strnlenpt(fileptr->data,
				startmatch.rm_so) - 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 = strnlenpt(fileptr->data,
				endmatch.rm_eo) - start - x_start;
			    if (x_start + paintlen > COLS)
				paintlen = COLS - x_start;

			    assert(0 <= x_start && 0 < paintlen &&
				x_start + paintlen <= COLS);
			    mvwaddnstr(edit, yval, x_start,
				converted + x_start, 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, yval, x_start,
				converted + x_start, COLS - x_start);
			    /* We painted to the end of the line, so
			     * don't bother checking any more starts. */
			    break;
			}
		    }
		    start_col = startmatch.rm_so + 1;
		} /* while start_col < endpos */
	    } /* if (tmp_color->end != NULL) */

  skip_step_two:
	    wattroff(edit, A_BOLD);
	    wattroff(edit, COLOR_PAIR(tmpcolor->pairnum));
	} /* for tmpcolor in colorstrings */
    }
#endif				/* ENABLE_COLOR */

#ifndef NANO_SMALL
    if (ISSET(MARK_ISSET)
	    && (fileptr->lineno <= mark_beginbuf->lineno
		|| fileptr->lineno <= current->lineno)
	    && (fileptr->lineno >= mark_beginbuf->lineno
		|| fileptr->lineno >= current->lineno)) {
	/* fileptr is at least partially selected. */

	const filestruct *top;
	    /* Either current or mark_beginbuf, whichever is first. */
	size_t top_x;
	    /* current_x or mark_beginx, corresponding to top. */
	const filestruct *bot;
	size_t bot_x;
	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. */

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

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

	    wattron(edit, A_REVERSE);
	    mvwaddnstr(edit, yval, x_start, converted + x_start, paintlen);
	    wattroff(edit, A_REVERSE);
	}
    }
#endif /* !NANO_SMALL */
}

/* Just update one line in the edit buffer.  Basically a wrapper for
 * edit_add().
 *
 * If fileptr != current, then index is considered 0.  The line will be
 * displayed starting with fileptr->data[index].  Likely args are
 * current_x or 0. */
void update_line(const filestruct *fileptr, size_t index)
{
    int line;
	/* line in the edit window for CURSES calls */
    char *converted;
	/* fileptr->data converted to have tabs and control characters
	 * expanded. */
    size_t page_start;

    assert(fileptr != NULL);

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

    /* We assume the line numbers are valid.  Is that really true? */
    assert(line < 0 || line == check_linenumbers(fileptr));

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

    /* First, blank out the line (at a minimum) */
    mvwaddstr(edit, line, 0, hblank);

    /* Next, convert variables that index the line to their equivalent
     * positions in the expanded line. */
    index = (fileptr == current) ? strnlenpt(fileptr->data, index) : 0;
    page_start = get_page_start(index);

    /* Expand the line, replacing Tab by spaces, and control characters
     * by their display form. */
    converted = display_string(fileptr->data, page_start, COLS);

    /* Now, paint the line */
    edit_add(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 a nonzero value if we need an update after moving
 * horizontally.  We need one if the mark is on or if old_pww and
 * placewewant are on different pages. */
int need_horizontal_update(int old_pww)
{
    return
#ifndef NANO_SMALL
	ISSET(MARK_ISSET) ||
#endif
	get_page_start(old_pww) != get_page_start(placewewant);
}

/* Return a nonzero value if we need an update after moving vertically.
 * We need one if the mark is on or if old_pww and placewewant
 * are on different pages. */
int need_vertical_update(int old_pww)
{
    return
#ifndef NANO_SMALL
	ISSET(MARK_ISSET) ||
#endif
	get_page_start(old_pww) != get_page_start(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 or DOWN,
 * and nlines is the number of lines to scroll.  Don't redraw the old
 * topmost or bottommost line (where we assume current is) before
 * scrolling or draw the new topmost or bottommost line after scrolling
 * (where we assume current will be), since we don't know where we are
 * on the page or whether we'll stay there. */
void edit_scroll(updown direction, int nlines)
{
    filestruct *foo;
    int i, scroll_rows = 0;

    /* Scrolling less than one line or more than editwinrows lines is
     * redundant, so don't allow it. */
    if (nlines < 1 || nlines > editwinrows)
	return;

    /* Move the top line of the edit window up or down (depending on the
     * value of direction) nlines lines.  If there are fewer lines of
     * text than that left, move it to the top or bottom line of the
     * file (depending on the value of direction).  Keep track of
     * how many lines we moved in scroll_rows. */
    for (i = nlines; i > 0; i--) {
	if (direction == UP) {
	    if (edittop->prev == NULL)
		break;
	    edittop = edittop->prev;
	    scroll_rows--;
	} else {
	    if (edittop->next == NULL)
		break;
	    edittop = edittop->next;
	    scroll_rows++;
	}
    }

    /* Scroll the text on the screen up or down scroll_rows lines,
     * depending on the value of direction. */
    scrollok(edit, TRUE);
    wscrl(edit, scroll_rows);
    scrollok(edit, FALSE);

    foo = edittop;
    if (direction != UP) {
	int slines = editwinrows - nlines;
	for (; slines > 0 && foo != NULL; slines--)
	    foo = foo->next;
    }

    /* And draw new lines on the blank top or bottom lines of the edit
     * window, depending on the value of direction.  Don't draw the new
     * topmost or new bottommost line. */
    while (scroll_rows != 0 && foo != NULL) {
	if (foo->next != NULL)
	    update_line(foo, 0);
	if (direction == UP)
	    scroll_rows++;
	else
	    scroll_rows--;
	foo = foo->next;
    }
}

/* Update any lines between old_current and current that need to be
 * updated. */
void edit_redraw(const filestruct *old_current, int old_pww)
{
    int do_refresh = need_vertical_update(0) ||
	need_vertical_update(old_pww);
    const filestruct *foo;

    /* If either old_current or current is offscreen, refresh the screen
     * and get out. */
    if (old_current->lineno < edittop->lineno || old_current->lineno >=
	edittop->lineno + editwinrows || current->lineno <
	edittop->lineno || current->lineno >= edittop->lineno +
	editwinrows) {
	edit_refresh();
	return;
    }

    /* Update old_current and current if we're not on the first page
     * and/or 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 != current) {
	if (do_refresh)
	    update_line(foo, 0);
#ifndef NANO_SMALL
	if (!ISSET(MARK_ISSET))
#endif
	    break;
	if (foo->lineno > current->lineno)
	    foo = foo->prev;
	else
	    foo = foo->next;
    }
    if (do_refresh)
	update_line(current, current_x);
}

/* Refresh the screen without changing the position of lines. */
void edit_refresh(void)
{
    /* Neither of these conditions should occur, but they do.  edittop
     * is NULL when you open an existing file on the command line, and
     * ENABLE_COLOR is defined.  Yuck. */
    if (current == NULL)
	return;
    if (edittop == NULL)
	edittop = current;

    if (current->lineno < edittop->lineno ||
	    current->lineno >= edittop->lineno + editwinrows)
	/* Note that edit_update() changes edittop so that
	 * current->lineno = edittop->lineno + editwinrows / 2.  Thus
	 * when it then calls edit_refresh(), there is no danger of
	 * getting an infinite loop. */
	edit_update(current, CENTER);
    else {
	int nlines = 0;
	const filestruct *foo = edittop;

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

	while (nlines < editwinrows) {
	    update_line(foo, foo == current ? current_x : 0);
	    nlines++;
	    if (foo->next == NULL)
		break;
	    foo = foo->next;
	}
	while (nlines < editwinrows) {
	    mvwaddstr(edit, nlines, 0, hblank);
	    nlines++;
	}
	reset_cursor();

	/* What the hell are we expecting to update the screen if this
	 * isn't here?  Luck? */
	wrefresh(edit);
    }
}

/* Nice generic routine to update the edit buffer, given a pointer to the
 * file struct =) */
void edit_update(filestruct *fileptr, topmidnone location)
{
    if (fileptr == NULL)
	return;

    if (location != TOP) {
	int goal = (location == NONE) ? current_y : editwinrows / 2;

	for (; goal > 0 && fileptr->prev != NULL; goal--)
	    fileptr = fileptr->prev;
    }
    edittop = fileptr;
    edit_refresh();
}

/* Ask a question on the statusbar.  Answer will be stored in answer
 * global.  Returns -1 on aborted enter, -2 on a blank string, and 0
 * otherwise, the valid shortcut key caught.  Def is any editable text we
 * want to put up by default.
 *
 * New arg tabs tells whether or not to allow tab completion. */
int statusq(int allowtabs, const shortcut *s, const char *def,
#ifndef NANO_SMALL
		historyheadtype *which_history,
#endif
		const char *msg, ...)
{
    va_list ap;
    char *foo = charalloc(COLS - 3);
    int ret;
#ifndef DISABLE_TABCOMP
    int list = 0;
#endif

    bottombars(s);

    va_start(ap, msg);
    vsnprintf(foo, COLS - 4, msg, ap);
    va_end(ap);
    foo[COLS - 4] = '\0';

    ret = nanogetstr(allowtabs, foo, def,
#ifndef NANO_SMALL
		which_history,
#endif
		s
#ifndef DISABLE_TABCOMP
		, &list
#endif
		);
    free(foo);
    resetstatuspos = 0;

    switch (ret) {
    case NANO_FIRSTLINE_KEY:
    case NANO_FIRSTLINE_FKEY:
	do_first_line();
	resetstatuspos = 1;
	break;
    case NANO_LASTLINE_KEY:
    case NANO_LASTLINE_FKEY:
	do_last_line();
	resetstatuspos = 1;
	break;
#ifndef DISABLE_JUSTIFY
    case NANO_PARABEGIN_KEY:
	do_para_begin();
	resetstatuspos = 1;
	break;
    case NANO_PARAEND_KEY:
	do_para_end();
	resetstatuspos = 1;
	break;
    case NANO_FULLJUSTIFY_KEY:
	if (!ISSET(VIEW_MODE))
	    do_full_justify();
	resetstatuspos = 1;
	break;
#endif
    case NANO_CANCEL_KEY:
	ret = -1;
	resetstatuspos = 1;
	break;
    }
    blank_statusbar();

#ifdef DEBUG
    fprintf(stderr, "I got \"%s\"\n", answer);
#endif

#ifndef DISABLE_TABCOMP
	/* if we've done tab completion, there might be a list of
	   filename matches on the edit window at this point; make sure
	   they're cleared off. */
	if (list)
	    edit_refresh();
#endif

    return ret;
}

/* Ask a simple yes/no question on the statusbar.  Returns 1 for Y, 0
 * for N, 2 for All (if all is nonzero when passed in) and -1 for abort
 * (^C). */
int do_yesno(int all, const char *msg)
{
    int ok = -2, width = 16;
    const char *yesstr;		/* String of yes characters accepted. */
    const char *nostr;		/* Same for no. */
    const char *allstr;		/* And all, surprise! */

    /* Yes, no and all are strings of any length.  Each string consists
     * of all characters accepted as a valid character for that value.
     * The first value will be the one displayed in the shortcuts. */
    yesstr = _("Yy");
    nostr = _("Nn");
    allstr = _("Aa");

    if (!ISSET(NO_HELP)) {
	char shortstr[3];		/* Temp string for Y, N, A. */

	if (COLS < 32)
	    width = COLS / 2;

	/* Write the bottom of the screen. */
	blank_bottombars();

	sprintf(shortstr, " %c", yesstr[0]);
	wmove(bottomwin, 1, 0);
	onekey(shortstr, _("Yes"), width);

	if (all) {
	    wmove(bottomwin, 1, width);
	    shortstr[1] = allstr[0];
	    onekey(shortstr, _("All"), width);
	}

	wmove(bottomwin, 2, 0);
	shortstr[1] = nostr[0];
	onekey(shortstr, _("No"), width);

	wmove(bottomwin, 2, 16);
	onekey("^C", _("Cancel"), width);
    }

    wattron(bottomwin, A_REVERSE);

    blank_statusbar();
    mvwaddnstr(bottomwin, 0, 0, msg, COLS - 1);

    wattroff(bottomwin, A_REVERSE);

    wrefresh(bottomwin);

    do {
	int kbinput;
	int meta_key;
#ifndef DISABLE_MOUSE
	int mouse_x, mouse_y;
#endif

	kbinput = get_kbinput(edit, &meta_key);

	if (kbinput == NANO_CANCEL_KEY)
	    ok = -1;
#ifndef DISABLE_MOUSE
	/* Look ma!  We get to duplicate lots of code from
	 * do_mouse()!! */
	else if (kbinput == KEY_MOUSE) {
	    kbinput = get_mouseinput(&mouse_x, &mouse_y, 0);

	    if (mouse_x != -1 && mouse_y != -1 && !ISSET(NO_HELP) &&
		wenclose(bottomwin, mouse_y, mouse_x) && mouse_x <
		(width * 2) && mouse_y >= editwinrows + 3) {

		int x = mouse_x / width;
		    /* Did we click in the first column of shortcuts, or
		     * the second? */
		int y = mouse_y - editwinrows - 3;
		    /* Did we click in the first row of shortcuts? */

		assert(0 <= x && x <= 1 && 0 <= y && y <= 1);

		/* x = 0 means they clicked Yes or No.
		 * y = 0 means Yes or All. */
		ok = -2 * x * y + x - y + 1;

		if (ok == 2 && !all)
		    ok = -2;
	    }
	}
#endif
	/* Look for the kbinput in the yes, no and (optionally) all
	 * str. */
	else if (strchr(yesstr, kbinput) != NULL)
	    ok = 1;
	else if (strchr(nostr, kbinput) != NULL)
	    ok = 0;
	else if (all && strchr(allstr, kbinput) != NULL)
	    ok = 2;
    } while (ok == -2);

    return ok;
}

int total_refresh(void)
{
    clearok(topwin, TRUE);
    clearok(edit, TRUE);
    clearok(bottomwin, TRUE);
    wnoutrefresh(topwin);
    wnoutrefresh(edit);
    wnoutrefresh(bottomwin);
    doupdate();
    clearok(topwin, FALSE);
    clearok(edit, FALSE);
    clearok(bottomwin, FALSE);
    edit_refresh();
    titlebar(NULL);
    return 1;
}

void display_main_list(void)
{
    bottombars(main_list);
}

/* If constant is FALSE, the user typed ^C so we unconditionally display
 * the cursor position.  Otherwise, we display it only if the character
 * position changed, and DISABLE_CURPOS is not set.
 *
 * If constant is TRUE and DISABLE_CURPOS is set, we unset it and update
 * old_i and old_totsize.  That way, we leave the current statusbar
 * alone, but next time we will display. */
int do_cursorpos(int constant)
{
    const filestruct *fileptr;
    unsigned long i = 0;
    static unsigned long old_i = 0;
    static long old_totsize = -1;

    assert(current != NULL && fileage != NULL && totlines != 0);

    if (old_totsize == -1)
	old_totsize = totsize;

    for (fileptr = fileage; fileptr != current; fileptr = fileptr->next) {
	assert(fileptr != NULL);
	i += strlen(fileptr->data) + 1;
    }
    i += current_x;

    if (constant && ISSET(DISABLE_CURPOS)) {
	UNSET(DISABLE_CURPOS);
	old_i = i;
	old_totsize = totsize;
	return 0;
    }

    /* If constant is FALSE, display the position on the statusbar
     * unconditionally; otherwise, only display the position when the
     * character values have changed. */
    if (!constant || old_i != i || old_totsize != totsize) {
	unsigned long xpt = xplustabs() + 1;
	unsigned long cur_len = strlenpt(current->data) + 1;
	int linepct = 100 * current->lineno / totlines;
	int colpct = 100 * xpt / cur_len;
	int bytepct = totsize == 0 ? 0 : 100 * i / totsize;

	statusbar(
	    _("line %ld/%ld (%d%%), col %lu/%lu (%d%%), char %lu/%ld (%d%%)"),
		    current->lineno, totlines, linepct,
		    xpt, cur_len, colpct,
		    i, totsize, bytepct);
	UNSET(DISABLE_CURPOS);
    }

    old_i = i;
    old_totsize = totsize;

    reset_cursor();
    return 0;
}

int do_cursorpos_void(void)
{
    return do_cursorpos(0);
}

/* Calculate the next line of help_text, starting at ptr. */
int line_len(const char *ptr)
{
    int j = 0;

    while (*ptr != '\n' && *ptr != '\0' && j < COLS - 5) {
	ptr++;
	j++;
    }
    if (j == COLS - 5) {
	/* Don't wrap at the first of two spaces following a period. */
	if (*ptr == ' ' && *(ptr + 1) == ' ')
	    j++;
	/* Don't print half a word if we've run out of space. */
	while (*ptr != ' ' && j > 0) {
	    ptr--;
	    j--;
	}
	/* Word longer than COLS - 5 chars just gets broken. */
	if (j == 0)
	    j = COLS - 5;
    }
    assert(j >= 0 && j <= COLS - 4 && (j > 0 || *ptr == '\n'));
    return j;
}

#ifndef DISABLE_HELP
/* Our shortcut-list-compliant help function, which is better than
 * nothing, and dynamic! */
int do_help(void)
{
    int line = 0;
	/* The line number in help_text of the first displayed help line.
	 * This variable is zero-based. */
    int no_more = 0;
	/* no_more means the end of the help text is shown, so don't go down
	 * any more. */
    int kbinput = ERR, meta_key;

    int old_no_help = ISSET(NO_HELP);
#ifndef DISABLE_MOUSE
    const shortcut *oldshortcut = currshortcut;
	/* We will set currshortcut to allow clicking on the help
	   screen shortcut list. */
#endif

    curs_set(0);
    blank_edit();
    wattroff(bottomwin, A_REVERSE);
    blank_statusbar();

    /* Set help_text as the string to display. */
    help_init();
    assert(help_text != NULL);

#ifndef DISABLE_MOUSE
    /* Set currshortcut to allow clicking on the help screen shortcut
     * list, AFTER help_init(). */
    currshortcut = help_list;
#endif

    if (ISSET(NO_HELP)) {
	/* Well, if we're going to do this, we should at least do it the
	 * right way. */
	UNSET(NO_HELP);
	window_init();
    }
    bottombars(help_list);

    do {
	int i;
	int old_line = line;
	    /* We redisplay the help only if it moved. */
	const char *ptr = help_text;

	switch (kbinput) {
#ifndef DISABLE_MOUSE
	    case KEY_MOUSE:
		do_mouse();
		break;
#endif
	    case NANO_NEXTPAGE_KEY:
	    case NANO_NEXTPAGE_FKEY:
		if (!no_more)
		    line += editwinrows - 2;
		break;
	    case NANO_PREVPAGE_KEY:
	    case NANO_PREVPAGE_FKEY:
		if (line > 0) {
		    line -= editwinrows - 2;
		    if (line < 0)
			line = 0;
		}
		break;
	    case NANO_PREVLINE_KEY:
		if (line > 0)
		    line--;
		break;
	    case NANO_NEXTLINE_KEY:
		if (!no_more)
		    line++;
		break;
	}

	if (line == old_line && kbinput != ERR)
	    goto skip_redisplay;

	blank_edit();

	assert(COLS > 5);

	/* Calculate where in the text we should be, based on the
	 * page. */
	for (i = 0; i < line; i++) {
	    ptr += line_len(ptr);
	    if (*ptr == '\n')
		ptr++;
	}

	for (i = 0; i < editwinrows && *ptr != '\0'; i++) {
	    int j = line_len(ptr);

	    mvwaddnstr(edit, i, 0, ptr, j);
	    ptr += j;
	    if (*ptr == '\n')
		ptr++;
	}
	no_more = (*ptr == '\0');

  skip_redisplay:
	kbinput = get_kbinput(edit, &meta_key);
    } while (kbinput != NANO_EXIT_KEY && kbinput != NANO_EXIT_FKEY);

#ifndef DISABLE_MOUSE
    currshortcut = oldshortcut;
#endif

    if (old_no_help) {
	blank_bottombars();
	wrefresh(bottomwin);
	SET(NO_HELP);
	window_init();
    } else
	bottombars(currshortcut);

    curs_set(1);
    edit_refresh();

    /* The help_init() at the beginning allocated help_text, which has
     * now been written to the screen. */
    free(help_text);
    help_text = NULL;

    return 1;
}
#endif /* !DISABLE_HELP */

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

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

    reset_cursor();

    if (highlight_flag)
	wattron(edit, A_REVERSE);

#ifdef HAVE_REGEX_H
    /* This is so we can show zero-length regexes. */
    if (word_len == 0)
	waddstr(edit, " ");
    else
#endif
	waddnstr(edit, word, y - 1);

    if (word_len > y)
	waddch(edit, '$');
    else if (word_len == y)
	waddch(edit, word[word_len - 1]);

    if (highlight_flag)
	wattroff(edit, A_REVERSE);
}

#ifdef DEBUG
/* Dump the passed-in file structure to stderr. */
void dump_buffer(const filestruct *inptr)
{
    if (inptr == fileage)
	fprintf(stderr, "Dumping file buffer to stderr...\n");
    else if (inptr == cutbuffer)
	fprintf(stderr, "Dumping cutbuffer to stderr...\n");
    else
	fprintf(stderr, "Dumping a buffer to stderr...\n");

    while (inptr != NULL) {
	fprintf(stderr, "(%d) %s\n", inptr->lineno, inptr->data);
	inptr = inptr->next;
    }
}

/* Dump the file structure to stderr in reverse. */
void dump_buffer_reverse(void)
{
    const filestruct *fileptr = filebot;

    while (fileptr != NULL) {
	fprintf(stderr, "(%d) %s\n", fileptr->lineno, fileptr->data);
	fileptr = fileptr->prev;
    }
}
#endif /* DEBUG */

#ifdef NANO_EXTRA
#define CREDIT_LEN 53
#define XLCREDIT_LEN 8

/* Easter egg: Display credits.  Assume nodelay(edit) is FALSE. */
void do_credits(void)
{
    int 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",
	"Ken Tyler",
	"Sven Guckes",
	"Florian König",
	"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) 1999-2004 Chris Allegretta",
	"",
	"",
	"",
	"",
	"http://www.nano-editor.org/"
    };

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

    curs_set(0);
    nodelay(edit, TRUE);
    scrollok(edit, TRUE);
    blank_titlebar();
    blank_edit();
    blank_statusbar();
    blank_bottombars();
    wrefresh(topwin);
    wrefresh(edit);
    wrefresh(bottomwin);

    for (crpos = 0; crpos < CREDIT_LEN + editwinrows / 2; crpos++) {
	if (wgetch(edit) != ERR)
	    break;
	if (crpos < CREDIT_LEN) {
	    const char *what = credits[crpos];
	    size_t start_x;

	    if (what == NULL) {
		assert(0 <= xlpos && xlpos < XLCREDIT_LEN);
		what = _(xlcredits[xlpos]);
		xlpos++;
	    }
	    start_x = COLS / 2 - strlen(what) / 2 - 1;
	    mvwaddstr(edit, editwinrows - 1 - editwinrows % 2, start_x, what);
	}
	napms(700);
	scroll(edit);
	wrefresh(edit);
	if (wgetch(edit) != ERR)
	    break;
	napms(700);
	scroll(edit);
	wrefresh(edit);
    }

    scrollok(edit, FALSE);
    nodelay(edit, FALSE);
    curs_set(1);
    display_main_list();
    total_refresh();
}
#endif