/* $OpenBSD: lib_getch.c,v 1.12 2023/10/17 09:52:08 nicm Exp $ */

/****************************************************************************
 * Copyright 2018-2022,2023 Thomas E. Dickey                                *
 * Copyright 1998-2015,2016 Free Software Foundation, Inc.                  *
 *                                                                          *
 * Permission is hereby granted, free of charge, to any person obtaining a  *
 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
 * without limitation the rights to use, copy, modify, merge, publish,      *
 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
 *                                                                          *
 * Except as contained in this notice, the name(s) of the above copyright   *
 * holders shall not be used in advertising or otherwise to promote the     *
 * sale, use or other dealings in this Software without prior written       *
 * authorization.                                                           *
 ****************************************************************************/

/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 *     and: Thomas E. Dickey                        1996-on                 *
 *     and: Juergen Pfeifer                         2009                    *
 ****************************************************************************/

/*
**      lib_getch.c
**
**      The routine getch().
**
*/

#define NEED_KEY_EVENT
#include <curses.priv.h>

MODULE_ID("$Id: lib_getch.c,v 1.12 2023/10/17 09:52:08 nicm Exp $")

#include <fifo_defs.h>

#if USE_REENTRANT
#define GetEscdelay(sp) *_nc_ptr_Escdelay(sp)
NCURSES_EXPORT(int)
NCURSES_PUBLIC_VAR(ESCDELAY) (void)
{
    return *(_nc_ptr_Escdelay(CURRENT_SCREEN));
}

NCURSES_EXPORT(int *)
_nc_ptr_Escdelay(SCREEN *sp)
{
    return ptrEscdelay(sp);
}
#else
#define GetEscdelay(sp) ESCDELAY
NCURSES_EXPORT_VAR(int) ESCDELAY = 1000;
#endif

#if NCURSES_EXT_FUNCS
NCURSES_EXPORT(int)
NCURSES_SP_NAME(set_escdelay) (NCURSES_SP_DCLx int value)
{
    int code = OK;
    if (value < 0) {
        code = ERR;
    } else {
#if USE_REENTRANT
        if (SP_PARM) {
            SET_ESCDELAY(value);
        } else {
            code = ERR;
        }
#else
        (void) SP_PARM;
        ESCDELAY = value;
#endif
    }
    return code;
}

#if NCURSES_SP_FUNCS
NCURSES_EXPORT(int)
set_escdelay(int value)
{
    int code;
    if (value < 0) {
        code = ERR;
    } else {
#if USE_REENTRANT
        code = NCURSES_SP_NAME(set_escdelay) (CURRENT_SCREEN, value);
#else
        ESCDELAY = value;
        code = OK;
#endif
    }
    return code;
}
#endif
#endif /* NCURSES_EXT_FUNCS */

#if NCURSES_EXT_FUNCS
NCURSES_EXPORT(int)
NCURSES_SP_NAME(get_escdelay) (NCURSES_SP_DCL0)
{
#if !USE_REENTRANT
    (void) SP_PARM;
#endif
    return GetEscdelay(SP_PARM);
}

#if NCURSES_SP_FUNCS
NCURSES_EXPORT(int)
get_escdelay(void)
{
    return NCURSES_SP_NAME(get_escdelay) (CURRENT_SCREEN);
}
#endif
#endif /* NCURSES_EXT_FUNCS */

static int
_nc_use_meta(WINDOW *win)
{
    SCREEN *sp = _nc_screen_of(win);
    return (sp ? sp->_use_meta : 0);
}

#ifdef USE_TERM_DRIVER
# if defined(_NC_WINDOWS) && !defined(EXP_WIN32_DRIVER)
static HANDLE
_nc_get_handle(int fd)
{
    intptr_t value = _get_osfhandle(fd);
    return (HANDLE) value;
}
# endif
#endif

/*
 * Check for mouse activity, returning nonzero if we find any.
 */
static int
check_mouse_activity(SCREEN *sp, int delay EVENTLIST_2nd(_nc_eventlist * evl))
{
    int rc;

#ifdef USE_TERM_DRIVER
    TERMINAL_CONTROL_BLOCK *TCB = TCBOf(sp);
    rc = TCBOf(sp)->drv->td_testmouse(TCBOf(sp), delay EVENTLIST_2nd(evl));
# if defined(EXP_WIN32_DRIVER)
    /* if we emulate terminfo on console, we have to use the console routine */
    if (IsTermInfoOnConsole(sp)) {
        rc = _nc_console_testmouse(sp,
                                   _nc_console_handle(sp->_ifd),
                                   delay EVENTLIST_2nd(evl));
    } else
# elif defined(_NC_WINDOWS)
    /* if we emulate terminfo on console, we have to use the console routine */
    if (IsTermInfoOnConsole(sp)) {
        HANDLE fd = _nc_get_handle(sp->_ifd);
        rc = _nc_mingw_testmouse(sp, fd, delay EVENTLIST_2nd(evl));
    } else
# endif
        rc = TCB->drv->td_testmouse(TCB, delay EVENTLIST_2nd(evl));
#else /* !USE_TERM_DRIVER */
# if USE_SYSMOUSE
    if ((sp->_mouse_type == M_SYSMOUSE)
        && (sp->_sysmouse_head < sp->_sysmouse_tail)) {
        rc = TW_MOUSE;
    } else
# endif
    {
# if defined(EXP_WIN32_DRIVER)
        rc = _nc_console_testmouse(sp,
                                   _nc_console_handle(sp->_ifd),
                                   delay
                                   EVENTLIST_2nd(evl));
# else
        rc = _nc_timed_wait(sp,
                            TWAIT_MASK,
                            delay,
                            (int *) 0
                            EVENTLIST_2nd(evl));
# endif
# if USE_SYSMOUSE
        if ((sp->_mouse_type == M_SYSMOUSE)
            && (sp->_sysmouse_head < sp->_sysmouse_tail)
            && (rc == 0)
            && (errno == EINTR)) {
            rc |= TW_MOUSE;
        }
# endif
    }
#endif /* USE_TERM_DRIVER */
    return rc;
}

static NCURSES_INLINE int
fifo_peek(SCREEN *sp)
{
    int ch = (peek >= 0) ? sp->_fifo[peek] : ERR;
    TR(TRACE_IEVENT, ("peeking at %d", peek));

    p_inc();
    return ch;
}

static NCURSES_INLINE int
fifo_pull(SCREEN *sp)
{
    int ch = (head >= 0) ? sp->_fifo[head] : ERR;

    TR(TRACE_IEVENT, ("pulling %s from %d", _nc_tracechar(sp, ch), head));

    if (peek == head) {
        h_inc();
        peek = head;
    } else {
        h_inc();
    }

#ifdef TRACE
    if (USE_TRACEF(TRACE_IEVENT)) {
        _nc_fifo_dump(sp);
        _nc_unlock_global(tracef);
    }
#endif
    return ch;
}

static NCURSES_INLINE int
fifo_push(SCREEN *sp EVENTLIST_2nd(_nc_eventlist * evl))
{
    int n;
    int ch = 0;
    int mask = 0;

    (void) mask;
    if (tail < 0)
        return ERR;

#ifdef NCURSES_WGETCH_EVENTS
    if (evl
#if USE_GPM_SUPPORT || USE_EMX_MOUSE || USE_SYSMOUSE
        || (sp->_mouse_fd >= 0)
#endif
        ) {
        mask = check_mouse_activity(sp, -1 EVENTLIST_2nd(evl));
    } else
        mask = 0;

    if (mask & TW_EVENT) {
        T(("fifo_push: ungetch KEY_EVENT"));
        safe_ungetch(sp, KEY_EVENT);
        return KEY_EVENT;
    }
#elif USE_GPM_SUPPORT || USE_EMX_MOUSE || USE_SYSMOUSE
    if (sp->_mouse_fd >= 0) {
        mask = check_mouse_activity(sp, -1 EVENTLIST_2nd(evl));
    }
#endif

#if USE_GPM_SUPPORT || USE_EMX_MOUSE
    if ((sp->_mouse_fd >= 0) && (mask & TW_MOUSE)) {
        sp->_mouse_event(sp);
        ch = KEY_MOUSE;
        n = 1;
    } else
#endif
#if USE_SYSMOUSE
        if ((sp->_mouse_type == M_SYSMOUSE)
            && (sp->_sysmouse_head < sp->_sysmouse_tail)) {
        sp->_mouse_event(sp);
        ch = KEY_MOUSE;
        n = 1;
    } else if ((sp->_mouse_type == M_SYSMOUSE)
               && (mask <= 0) && errno == EINTR) {
        sp->_mouse_event(sp);
        ch = KEY_MOUSE;
        n = 1;
    } else
#endif
#ifdef USE_TERM_DRIVER
        if ((sp->_mouse_type == M_TERM_DRIVER)
            && (sp->_drv_mouse_head < sp->_drv_mouse_tail)) {
        sp->_mouse_event(sp);
        ch = KEY_MOUSE;
        n = 1;
    } else
#endif
#if USE_KLIBC_KBD
    if (NC_ISATTY(sp->_ifd) && IsCbreak(sp)) {
        ch = _read_kbd(0, 1, !IsRaw(sp));
        n = (ch == -1) ? -1 : 1;
        sp->_extended_key = (ch == 0);
    } else
#endif
    {                           /* Can block... */
#if defined(USE_TERM_DRIVER)
        int buf;
# if defined(EXP_WIN32_DRIVER)
        if (NC_ISATTY(sp->_ifd) && IsTermInfoOnConsole(sp) && IsCbreak(sp)) {
            _nc_set_read_thread(TRUE);
            n = _nc_console_read(sp,
                                 _nc_console_handle(sp->_ifd),
                                 &buf);
            _nc_set_read_thread(FALSE);
        } else
# elif defined(_NC_WINDOWS)
        if (NC_ISATTY(sp->_ifd) && IsTermInfoOnConsole(sp) && IsCbreak(sp))
            n = _nc_mingw_console_read(sp,
                                       _nc_get_handle(sp->_ifd),
                                       &buf);
        else
# endif /* EXP_WIN32_DRIVER */
            n = CallDriver_1(sp, td_read, &buf);
        ch = buf;
#else /* !USE_TERM_DRIVER */
#if defined(EXP_WIN32_DRIVER)
        int buf;
#endif
        unsigned char c2 = 0;

        _nc_set_read_thread(TRUE);
#if defined(EXP_WIN32_DRIVER)
        n = _nc_console_read(sp,
                             _nc_console_handle(sp->_ifd),
                             &buf);
        c2 = buf;
#else
        n = (int) read(sp->_ifd, &c2, (size_t) 1);
#endif
        _nc_set_read_thread(FALSE);
        ch = c2;
#endif /* USE_TERM_DRIVER */
    }

    if ((n == -1) || (n == 0)) {
        TR(TRACE_IEVENT, ("read(%d,&ch,1)=%d, errno=%d", sp->_ifd, n, errno));
        ch = ERR;
    }
    TR(TRACE_IEVENT, ("read %d characters", n));

    sp->_fifo[tail] = ch;
    sp->_fifohold = 0;
    if (head == -1)
        head = peek = tail;
    t_inc();
    TR(TRACE_IEVENT, ("pushed %s at %d", _nc_tracechar(sp, ch), tail));
#ifdef TRACE
    if (USE_TRACEF(TRACE_IEVENT)) {
        _nc_fifo_dump(sp);
        _nc_unlock_global(tracef);
    }
#endif
    return ch;
}

static NCURSES_INLINE void
fifo_clear(SCREEN *sp)
{
    memset(sp->_fifo, 0, sizeof(sp->_fifo));
    head = -1;
    tail = peek = 0;
}

static int kgetch(SCREEN *, bool EVENTLIST_2nd(_nc_eventlist *));

static void
recur_wrefresh(WINDOW *win)
{
#ifdef USE_PTHREADS
    SCREEN *sp = _nc_screen_of(win);
    bool same_sp;

    if (_nc_use_pthreads) {
        _nc_lock_global(curses);
        same_sp = (sp == CURRENT_SCREEN);
        _nc_unlock_global(curses);
    } else {
        same_sp = (sp == CURRENT_SCREEN);
    }

    if (_nc_use_pthreads && !same_sp) {
        SCREEN *save_SP;

        /* temporarily switch to the window's screen to check/refresh */
        _nc_lock_global(curses);
        save_SP = CURRENT_SCREEN;
        _nc_set_screen(sp);
        recur_wrefresh(win);
        _nc_set_screen(save_SP);
        _nc_unlock_global(curses);
    } else
#endif
        if ((is_wintouched(win) || (win->_flags & _HASMOVED))
            && !IS_PAD(win)) {
        wrefresh(win);
    }
}

static int
recur_wgetnstr(WINDOW *win, char *buf)
{
    SCREEN *sp = _nc_screen_of(win);
    int rc;

    if (sp != 0) {
#ifdef USE_PTHREADS
        if (_nc_use_pthreads && sp != CURRENT_SCREEN) {
            SCREEN *save_SP;

            /* temporarily switch to the window's screen to get cooked input */
            _nc_lock_global(curses);
            save_SP = CURRENT_SCREEN;
            _nc_set_screen(sp);
            rc = recur_wgetnstr(win, buf);
            _nc_set_screen(save_SP);
            _nc_unlock_global(curses);
        } else
#endif
        {
            sp->_called_wgetch = TRUE;
            rc = wgetnstr(win, buf, MAXCOLUMNS);
            sp->_called_wgetch = FALSE;
        }
    } else {
        rc = ERR;
    }
    return rc;
}

NCURSES_EXPORT(int)
_nc_wgetch(WINDOW *win,
           int *result,
           int use_meta
           EVENTLIST_2nd(_nc_eventlist * evl))
{
    SCREEN *sp;
    int ch;
    int rc = 0;
#ifdef NCURSES_WGETCH_EVENTS
    int event_delay = -1;
#endif

    T((T_CALLED("_nc_wgetch(%p)"), (void *) win));

    *result = 0;

    sp = _nc_screen_of(win);
    if (win == 0 || sp == 0) {
        returnCode(ERR);
    }

    if (cooked_key_in_fifo()) {
        recur_wrefresh(win);
        *result = fifo_pull(sp);
        returnCode(*result >= KEY_MIN ? KEY_CODE_YES : OK);
    }
#ifdef NCURSES_WGETCH_EVENTS
    if (evl && (evl->count == 0))
        evl = NULL;
    event_delay = _nc_eventlist_timeout(evl);
#endif

    /*
     * Handle cooked mode.  Grab a string from the screen,
     * stuff its contents in the FIFO queue, and pop off
     * the first character to return it.
     */
    if (head == -1 &&
        !sp->_notty &&
        !IsRaw(sp) &&
        !IsCbreak(sp) &&
        !sp->_called_wgetch) {
        char buf[MAXCOLUMNS], *bufp;

        TR(TRACE_IEVENT, ("filling queue in cooked mode"));

        /* ungetch in reverse order */
#ifdef NCURSES_WGETCH_EVENTS
        rc = recur_wgetnstr(win, buf);
        if (rc != KEY_EVENT && rc != ERR)
            safe_ungetch(sp, '\n');
#else
        if (recur_wgetnstr(win, buf) != ERR)
            safe_ungetch(sp, '\n');
#endif
        for (bufp = buf + strlen(buf); bufp > buf; bufp--)
            safe_ungetch(sp, bufp[-1]);

#ifdef NCURSES_WGETCH_EVENTS
        /* Return it first */
        if (rc == KEY_EVENT) {
            *result = rc;
        } else
#endif
            *result = fifo_pull(sp);
        returnCode(*result >= KEY_MIN ? KEY_CODE_YES : OK);
    }

    if (win->_use_keypad != sp->_keypad_on)
        _nc_keypad(sp, win->_use_keypad);

    recur_wrefresh(win);

    if (win->_notimeout || (win->_delay >= 0) || (IsCbreak(sp) > 1)) {
        if (head == -1) {       /* fifo is empty */
            int delay;

            TR(TRACE_IEVENT, ("timed delay in wgetch()"));
            if (IsCbreak(sp) > 1)
                delay = (IsCbreak(sp) - 1) * 100;
            else
                delay = win->_delay;

#ifdef NCURSES_WGETCH_EVENTS
            if (event_delay >= 0 && delay > event_delay)
                delay = event_delay;
#endif

            TR(TRACE_IEVENT, ("delay is %d milliseconds", delay));

            rc = check_mouse_activity(sp, delay EVENTLIST_2nd(evl));

#ifdef NCURSES_WGETCH_EVENTS
            if (rc & TW_EVENT) {
                *result = KEY_EVENT;
                returnCode(KEY_CODE_YES);
            }
#endif
            if (!rc) {
                goto check_sigwinch;
            }
        }
        /* else go on to read data available */
    }

    if (win->_use_keypad) {
        /*
         * This is tricky.  We only want to get special-key
         * events one at a time.  But we want to accumulate
         * mouse events until either (a) the mouse logic tells
         * us it has picked up a complete gesture, or (b)
         * there's a detectable time lapse after one.
         *
         * Note: if the mouse code starts failing to compose
         * press/release events into clicks, you should probably
         * increase the wait with mouseinterval().
         */
        int runcount = 0;

        do {
            ch = kgetch(sp, win->_notimeout EVENTLIST_2nd(evl));
            if (ch == KEY_MOUSE) {
                ++runcount;
                if (sp->_mouse_inline(sp))
                    break;
            }
            if (sp->_maxclick < 0)
                break;
        } while
            (ch == KEY_MOUSE
             && (((rc = check_mouse_activity(sp, sp->_maxclick
                                             EVENTLIST_2nd(evl))) != 0
                  && !(rc & TW_EVENT))
                 || !sp->_mouse_parse(sp, runcount)));
#ifdef NCURSES_WGETCH_EVENTS
        if ((rc & TW_EVENT) && !(ch == KEY_EVENT)) {
            safe_ungetch(sp, ch);
            ch = KEY_EVENT;
        }
#endif
        if (runcount > 0 && ch != KEY_MOUSE) {
#ifdef NCURSES_WGETCH_EVENTS
            /* mouse event sequence ended by an event, report event */
            if (ch == KEY_EVENT) {
                safe_ungetch(sp, KEY_MOUSE);    /* FIXME This interrupts a gesture... */
            } else
#endif
            {
                /* mouse event sequence ended by keystroke, store keystroke */
                safe_ungetch(sp, ch);
                ch = KEY_MOUSE;
            }
        }
    } else {
        if (head == -1)
            fifo_push(sp EVENTLIST_2nd(evl));
        ch = fifo_pull(sp);
    }

    if (ch == ERR) {
      check_sigwinch:
#if USE_SIZECHANGE
        if (_nc_handle_sigwinch(sp)) {
            _nc_update_screensize(sp);
            /* resizeterm can push KEY_RESIZE */
            if (cooked_key_in_fifo()) {
                *result = fifo_pull(sp);
                /*
                 * Get the ERR from queue -- it is from WINCH,
                 * so we should take it out, the "error" is handled.
                 */
                if (fifo_peek(sp) == -1)
                    fifo_pull(sp);
                returnCode(*result >= KEY_MIN ? KEY_CODE_YES : OK);
            }
        }
#endif
        returnCode(ERR);
    }

    /*
     * If echo() is in effect, display the printable version of the
     * key on the screen.  Carriage return and backspace are treated
     * specially by Solaris curses:
     *
     * If carriage return is defined as a function key in the
     * terminfo, e.g., kent, then Solaris may return either ^J (or ^M
     * if nonl() is set) or KEY_ENTER depending on the echo() mode.
     * We echo before translating carriage return based on nonl(),
     * since the visual result simply moves the cursor to column 0.
     *
     * Backspace is a different matter.  Solaris curses does not
     * translate it to KEY_BACKSPACE if kbs=^H.  This does not depend
     * on the stty modes, but appears to be a hardcoded special case.
     * This is a difference from ncurses, which uses the terminfo entry.
     * However, we provide the same visual result as Solaris, moving the
     * cursor to the left.
     */
    if (IsEcho(sp) && !IS_PAD(win)) {
        chtype backup = (chtype) ((ch == KEY_BACKSPACE) ? '\b' : ch);
        if (backup < KEY_MIN)
            wechochar(win, backup);
    }

    /*
     * Simulate ICRNL mode
     */
    if ((ch == '\r') && IsNl(sp))
        ch = '\n';

    /* Strip 8th-bit if so desired.  We do this only for characters that
     * are in the range 128-255, to provide compatibility with terminals
     * that display only 7-bit characters.  Note that 'ch' may be a
     * function key at this point, so we mustn't strip _those_.
     */
    if (!use_meta)
        if ((ch < KEY_MIN) && (ch & 0x80))
            ch &= 0x7f;

    T(("wgetch returning : %s", _nc_tracechar(sp, ch)));

    *result = ch;
    returnCode(ch >= KEY_MIN ? KEY_CODE_YES : OK);
}

#ifdef NCURSES_WGETCH_EVENTS
NCURSES_EXPORT(int)
wgetch_events(WINDOW *win, _nc_eventlist * evl)
{
    int code;
    int value;

    T((T_CALLED("wgetch_events(%p,%p)"), (void *) win, (void *) evl));
    code = _nc_wgetch(win,
                      &value,
                      _nc_use_meta(win)
                      EVENTLIST_2nd(evl));
    if (code != ERR)
        code = value;
    returnCode(code);
}
#endif

NCURSES_EXPORT(int)
wgetch(WINDOW *win)
{
    int code;
    int value;

    T((T_CALLED("wgetch(%p)"), (void *) win));
    code = _nc_wgetch(win,
                      &value,
                      _nc_use_meta(win)
                      EVENTLIST_2nd((_nc_eventlist *) 0));
    if (code != ERR)
        code = value;
    returnCode(code);
}

/*
**      int
**      kgetch()
**
**      Get an input character, but take care of keypad sequences, returning
**      an appropriate code when one matches the input.  After each character
**      is received, set an alarm call based on ESCDELAY.  If no more of the
**      sequence is received by the time the alarm goes off, pass through
**      the sequence gotten so far.
**
**      This function must be called when there are no cooked keys in queue.
**      (that is head==-1 || peek==head)
**
*/

static int
kgetch(SCREEN *sp, bool forever EVENTLIST_2nd(_nc_eventlist * evl))
{
    TRIES *ptr;
    int ch = 0;
    int timeleft = forever ? 9999999 : GetEscdelay(sp);

    TR(TRACE_IEVENT, ("kgetch() called"));

    ptr = sp->_keytry;

    for (;;) {
        if (cooked_key_in_fifo() && sp->_fifo[head] >= KEY_MIN) {
            break;
        } else if (!raw_key_in_fifo()) {
            ch = fifo_push(sp EVENTLIST_2nd(evl));
            if (ch == ERR) {
                peek = head;    /* the keys stay uninterpreted */
                return ERR;
            }
#ifdef NCURSES_WGETCH_EVENTS
            else if (ch == KEY_EVENT) {
                peek = head;    /* the keys stay uninterpreted */
                return fifo_pull(sp);   /* Remove KEY_EVENT from the queue */
            }
#endif
        }

        ch = fifo_peek(sp);
        if (ch >= KEY_MIN) {
            /* If not first in queue, somebody put this key there on purpose in
             * emergency.  Consider it higher priority than the unfinished
             * keysequence we are parsing.
             */
            peek = head;
            /* assume the key is the last in fifo */
            t_dec();            /* remove the key */
            return ch;
        }

        TR(TRACE_IEVENT, ("ch: %s", _nc_tracechar(sp, (unsigned char) ch)));
        while ((ptr != NULL) && (ptr->ch != (unsigned char) ch))
            ptr = ptr->sibling;

        if (ptr == NULL) {
            TR(TRACE_IEVENT, ("ptr is null"));
            break;
        }
        TR(TRACE_IEVENT, ("ptr=%p, ch=%d, value=%d",
                          (void *) ptr, ptr->ch, ptr->value));

        if (ptr->value != 0) {  /* sequence terminated */
            TR(TRACE_IEVENT, ("end of sequence"));
            if (peek == tail) {
                fifo_clear(sp);
            } else {
                head = peek;
            }
            return (ptr->value);
        }

        ptr = ptr->child;

        if (!raw_key_in_fifo()) {
            int rc;

            TR(TRACE_IEVENT, ("waiting for rest of sequence"));
            rc = check_mouse_activity(sp, timeleft EVENTLIST_2nd(evl));
#ifdef NCURSES_WGETCH_EVENTS
            if (rc & TW_EVENT) {
                TR(TRACE_IEVENT, ("interrupted by a user event"));
                /* FIXME Should have preserved remainder timeleft for reuse... */
                peek = head;    /* Restart interpreting later */
                return KEY_EVENT;
            }
#endif
            if (!rc) {
                TR(TRACE_IEVENT, ("ran out of time"));
                break;
            }
        }
    }
    ch = fifo_pull(sp);
    peek = head;
    return ch;
}