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/*  $OpenBSD: input.c,v 1.12 2005/04/13 02:33:08 deraadt Exp $  */

/*    $NetBSD: input.c,v 1.3 1996/02/06 22:47:33 jtc Exp $    */

/*-

 * Copyright (c) 1992, 1993

 *  The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Chris Torek and Darren F. Provine.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 *  @(#)input.c 8.1 (Berkeley) 5/31/93

 */

/** @addtogroup tetris

 * @{

 */

/** @file

 */

/*

 * Tetris input.

 */

#include <sys/types.h>

#include <sys/time.h>

#include <stdio.h>

#include <errno.h>

#include <unistd.h>

#include <string.h>

#include "input.h"

#include "tetris.h"

#include <async.h>

#include "../console/console.h"

/* return true iff the given timeval is positive */

#define TV_POS(tv) \

    ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0))

/* subtract timeval `sub' from `res' */

#define TV_SUB(res, sub) \

    (res)->tv_sec -= (sub)->tv_sec; \

    (res)->tv_usec -= (sub)->tv_usec; \

    if ((res)->tv_usec < 0) { \

        (res)->tv_usec += 1000000; \

        (res)->tv_sec--; \

    }

/* We will use a hack here - if lastchar is non-zero, it is

 * the last character read. We will somehow simulate the select

 * semantics.

 */

static aid_t getchar_inprog = 0;

static char lastchar = '\0';

/*

 * Do a `read wait': select for reading from stdin, with timeout *tvp.

 * On return, modify *tvp to reflect the amount of time spent waiting.

 * It will be positive only if input appeared before the time ran out;

 * otherwise it will be zero or perhaps negative.

 *

 * If tvp is nil, wait forever, but return if select is interrupted.

 *

 * Return 0 => no input, 1 => can read() from stdin

 *

 */

int

rwait(struct timeval *tvp)

{

    struct timeval starttv, endtv, *s;

    static ipc_call_t charcall;

    ipcarg_t rc;

    /*

     * Someday, select() will do this for us.

     * Just in case that day is now, and no one has

     * changed this, we use a temporary.

     */

    if (tvp) {

        (void) gettimeofday(&starttv, NULL);

        endtv = *tvp;

        s = &endtv;

    } else

        s = NULL;

    if (!lastchar) {

        if (!getchar_inprog)

            getchar_inprog = async_send_2(1,CONSOLE_GETCHAR,0,0,&charcall);

        if (!s)

            async_wait_for(getchar_inprog, &rc);

        else if (async_wait_timeout(getchar_inprog, &rc, s->tv_usec) == ETIMEOUT) {

            tvp->tv_sec = 0;

            tvp->tv_usec = 0;

            return (0);

        }

        getchar_inprog = 0;

        if (rc) {

            stop("end of file, help");

        }

        lastchar = IPC_GET_ARG1(charcall);

    }

    if (tvp) {

        /* since there is input, we may not have timed out */

        (void) gettimeofday(&endtv, NULL);

        TV_SUB(&endtv, &starttv);

        TV_SUB(tvp, &endtv);    /* adjust *tvp by elapsed time */

    }

    return (1);

}

/*

 * `sleep' for the current turn time (using select).

 * Eat any input that might be available.

 */

void

tsleep(void)

{

    struct timeval tv;

    tv.tv_sec = 0;

    tv.tv_usec = fallrate;

    while (TV_POS(&tv))

        if (rwait(&tv)) {

            lastchar = '\0';

        } else

            break;

}

/*

 * getchar with timeout.

 */

int

tgetchar(void)

{

    static struct timeval timeleft;

    char c;

    /*

     * Reset timeleft to fallrate whenever it is not positive.

     * In any case, wait to see if there is any input.  If so,

     * take it, and update timeleft so that the next call to

     * tgetchar() will not wait as long.  If there is no input,

     * make timeleft zero or negative, and return -1.

     *

     * Most of the hard work is done by rwait().

     */

    if (!TV_POS(&timeleft)) {

        faster();   /* go faster */

        timeleft.tv_sec = 0;

        timeleft.tv_usec = fallrate;

    }

    if (!rwait(&timeleft))

        return (-1);

    c = lastchar;

    lastchar = '\0';

    return ((int)(unsigned char)c);

}

/** @}

 */