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  1. /*  $OpenBSD: input.c,v 1.12 2005/04/13 02:33:08 deraadt Exp $  */
  2. /*    $NetBSD: input.c,v 1.3 1996/02/06 22:47:33 jtc Exp $    */
  3.  
  4. /*-
  5.  * Copyright (c) 1992, 1993
  6.  *  The Regents of the University of California.  All rights reserved.
  7.  *
  8.  * This code is derived from software contributed to Berkeley by
  9.  * Chris Torek and Darren F. Provine.
  10.  *
  11.  * Redistribution and use in source and binary forms, with or without
  12.  * modification, are permitted provided that the following conditions
  13.  * are met:
  14.  * 1. Redistributions of source code must retain the above copyright
  15.  *    notice, this list of conditions and the following disclaimer.
  16.  * 2. Redistributions in binary form must reproduce the above copyright
  17.  *    notice, this list of conditions and the following disclaimer in the
  18.  *    documentation and/or other materials provided with the distribution.
  19.  * 3. Neither the name of the University nor the names of its contributors
  20.  *    may be used to endorse or promote products derived from this software
  21.  *    without specific prior written permission.
  22.  *
  23.  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24.  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26.  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27.  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28.  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29.  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30.  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31.  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32.  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33.  * SUCH DAMAGE.
  34.  *
  35.  *  @(#)input.c 8.1 (Berkeley) 5/31/93
  36.  */
  37.  
  38. /*
  39.  * Tetris input.
  40.  */
  41.  
  42. #include <sys/types.h>
  43. #include <sys/time.h>
  44.  
  45. #include <errno.h>
  46. #include <unistd.h>
  47. #include <string.h>
  48.  
  49. #include "input.h"
  50. #include "tetris.h"
  51.  
  52. #include <async.h>
  53. #include "../console/console.h"
  54.  
  55. /* return true iff the given timeval is positive */
  56. #define TV_POS(tv) \
  57.     ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0))
  58.  
  59. /* subtract timeval `sub' from `res' */
  60. #define TV_SUB(res, sub) \
  61.     (res)->tv_sec -= (sub)->tv_sec; \
  62.     (res)->tv_usec -= (sub)->tv_usec; \
  63.     if ((res)->tv_usec < 0) { \
  64.         (res)->tv_usec += 1000000; \
  65.         (res)->tv_sec--; \
  66.     }
  67.  
  68. /* We will use a hack here - if lastchar is non-zero, it is
  69.  * the last character read. We will somehow simulate the select
  70.  * semantics.
  71.  */
  72. static aid_t getchar_inprog = 0;
  73. static char lastchar = '\0';
  74.  
  75. /*
  76.  * Do a `read wait': select for reading from stdin, with timeout *tvp.
  77.  * On return, modify *tvp to reflect the amount of time spent waiting.
  78.  * It will be positive only if input appeared before the time ran out;
  79.  * otherwise it will be zero or perhaps negative.
  80.  *
  81.  * If tvp is nil, wait forever, but return if select is interrupted.
  82.  *
  83.  * Return 0 => no input, 1 => can read() from stdin
  84.  *
  85.  */
  86. int
  87. rwait(struct timeval *tvp)
  88. {
  89.     struct timeval starttv, endtv, *s;
  90.     static ipc_call_t charcall;
  91.     int rc;
  92.  
  93. #define NILTZ ((struct timezone *)0)
  94.  
  95.     /*
  96.      * Someday, select() will do this for us.
  97.      * Just in case that day is now, and no one has
  98.      * changed this, we use a temporary.
  99.      */
  100.     if (tvp) {
  101.         (void) gettimeofday(&starttv, NILTZ);
  102.         endtv = *tvp;
  103.         s = &endtv;
  104.     } else
  105.         s = NULL;
  106. again:
  107.     if (!lastchar) {
  108.         if (!getchar_inprog)
  109.             getchar_inprog = async_send_2(1,CONSOLE_GETCHAR,0,0,&charcall);
  110.         if (async_wait_timeout(getchar_inprog, &rc, s->tv_usec) == ETIMEOUT) {
  111.             tvp->tv_sec = 0;
  112.             tvp->tv_usec = 0;
  113.             return (0);
  114.         }
  115.         getchar_inprog = 0;
  116.         if (rc) {
  117.             stop("end of file, help");
  118.         }
  119.         lastchar = IPC_GET_ARG1(charcall);
  120.     }
  121.     if (tvp) {
  122.         /* since there is input, we may not have timed out */
  123.         (void) gettimeofday(&endtv, NILTZ);
  124.         TV_SUB(&endtv, &starttv);
  125.         TV_SUB(tvp, &endtv);    /* adjust *tvp by elapsed time */
  126.     }
  127.     return (1);
  128. }
  129.  
  130. /*
  131.  * `sleep' for the current turn time (using select).
  132.  * Eat any input that might be available.
  133.  */
  134. void
  135. tsleep(void)
  136. {
  137.     struct timeval tv;
  138.     char c;
  139.  
  140.     tv.tv_sec = 0;
  141.     tv.tv_usec = fallrate;
  142.     while (TV_POS(&tv))
  143.         if (rwait(&tv)) {
  144.             lastchar = '\0';
  145.         } else
  146.             break;
  147. }
  148.  
  149. /*
  150.  * getchar with timeout.
  151.  */
  152. int
  153. tgetchar(void)
  154. {
  155.     static struct timeval timeleft;
  156.     char c;
  157.  
  158.     /*
  159.      * Reset timeleft to fallrate whenever it is not positive.
  160.      * In any case, wait to see if there is any input.  If so,
  161.      * take it, and update timeleft so that the next call to
  162.      * tgetchar() will not wait as long.  If there is no input,
  163.      * make timeleft zero or negative, and return -1.
  164.      *
  165.      * Most of the hard work is done by rwait().
  166.      */
  167.     if (!TV_POS(&timeleft)) {
  168.         faster();   /* go faster */
  169.         timeleft.tv_sec = 0;
  170.         timeleft.tv_usec = fallrate;
  171.     }
  172.     if (!rwait(&timeleft))
  173.         return (-1);
  174.     c = lastchar;
  175.     lastchar = '\0';
  176.     return ((int)(unsigned char)c);
  177. }
  178.