168 lines
4.6 KiB
C
168 lines
4.6 KiB
C
/* $NetBSD: input.c,v 1.5 2002/06/02 22:17:38 wiz Exp $ */
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/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek and Darren F. Provine.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)input.c 8.1 (Berkeley) 5/31/93
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*/
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/*
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* Tetris input.
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*/
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#include <sys/types.h>
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#include <sys/time.h>
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#include <errno.h>
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#include <unistd.h>
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#include "input.h"
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#include "tetris.h"
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/* return true iff the given timeval is positive */
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#define TV_POS(tv) \
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((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0))
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/* subtract timeval `sub' from `res' */
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#define TV_SUB(res, sub) \
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(res)->tv_sec -= (sub)->tv_sec; \
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(res)->tv_usec -= (sub)->tv_usec; \
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if ((res)->tv_usec < 0) { \
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(res)->tv_usec += 1000000; \
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(res)->tv_sec--; \
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}
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/*
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* Do a `read wait': select for reading from stdin, with timeout *tvp.
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* On return, modify *tvp to reflect the amount of time spent waiting.
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* It will be positive only if input appeared before the time ran out;
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* otherwise it will be zero or perhaps negative.
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*
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* If tvp is nil, wait forever, but return if select is interrupted.
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*
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* Return 0 => no input, 1 => can read() from stdin
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*/
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int
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rwait(tvp)
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struct timeval *tvp;
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{
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int i;
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struct timeval starttv, endtv, *s;
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#define NILTZ ((struct timezone *)0)
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/*
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* Someday, select() will do this for us.
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* Just in case that day is now, and no one has
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* changed this, we use a temporary.
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*/
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if (tvp) {
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(void) gettimeofday(&starttv, NILTZ);
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endtv = *tvp;
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s = &endtv;
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} else
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s = 0;
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again:
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i = 1;
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switch (select(1, (fd_set *)&i, (fd_set *)0, (fd_set *)0, s)) {
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case -1:
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if (tvp == 0)
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return (-1);
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if (errno == EINTR)
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goto again;
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stop("select failed, help");
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/* NOTREACHED */
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case 0: /* timed out */
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tvp->tv_sec = 0;
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tvp->tv_usec = 0;
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return (0);
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}
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if (tvp) {
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/* since there is input, we may not have timed out */
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(void) gettimeofday(&endtv, NILTZ);
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TV_SUB(&endtv, &starttv);
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TV_SUB(tvp, &endtv); /* adjust *tvp by elapsed time */
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}
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return (1);
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}
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/*
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* `sleep' for the current turn time (using select).
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* Eat any input that might be available.
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*/
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void
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tsleep()
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{
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struct timeval tv;
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char c;
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tv.tv_sec = 0;
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tv.tv_usec = fallrate;
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while (TV_POS(&tv))
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if (rwait(&tv) && read(0, &c, 1) != 1)
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break;
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}
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/*
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* getchar with timeout.
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*/
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int
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tgetchar()
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{
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static struct timeval timeleft;
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char c;
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/*
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* Reset timeleft to fallrate whenever it is not positive.
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* In any case, wait to see if there is any input. If so,
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* take it, and update timeleft so that the next call to
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* tgetchar() will not wait as long. If there is no input,
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* make timeleft zero or negative, and return -1.
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*
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* Most of the hard work is done by rwait().
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*/
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if (!TV_POS(&timeleft)) {
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faster(); /* go faster */
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timeleft.tv_sec = 0;
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timeleft.tv_usec = fallrate;
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}
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if (!rwait(&timeleft))
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return (-1);
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if (read(0, &c, 1) != 1)
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stop("end of file, help");
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return ((int)(unsigned char)c);
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}
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