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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. #include <stdio.h>
  45.  
  46. #include <errno.h>
  47. #include <unistd.h>
  48. #include <string.h>
  49.  
  50. #include "input.h"
  51. #include "tetris.h"
  52.  
  53. #include <async.h>
  54. #include "../console/console.h"
  55.  
  56. /* return true iff the given timeval is positive */
  57. #define TV_POS(tv) \
  58.     ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0))
  59.  
  60. /* subtract timeval `sub' from `res' */
  61. #define TV_SUB(res, sub) \
  62.     (res)->tv_sec -= (sub)->tv_sec; \
  63.     (res)->tv_usec -= (sub)->tv_usec; \
  64.     if ((res)->tv_usec < 0) { \
  65.         (res)->tv_usec += 1000000; \
  66.         (res)->tv_sec--; \
  67.     }
  68.  
  69. /* We will use a hack here - if lastchar is non-zero, it is
  70.  * the last character read. We will somehow simulate the select
  71.  * semantics.
  72.  */
  73. static aid_t getchar_inprog = 0;
  74. static char lastchar = '\0';
  75.  
  76. /*
  77.  * Do a `read wait': select for reading from stdin, with timeout *tvp.
  78.  * On return, modify *tvp to reflect the amount of time spent waiting.
  79.  * It will be positive only if input appeared before the time ran out;
  80.  * otherwise it will be zero or perhaps negative.
  81.  *
  82.  * If tvp is nil, wait forever, but return if select is interrupted.
  83.  *
  84.  * Return 0 => no input, 1 => can read() from stdin
  85.  *
  86.  */
  87. int
  88. rwait(struct timeval *tvp)
  89. {
  90.     struct timeval starttv, endtv, *s;
  91.     static ipc_call_t charcall;
  92.     ipcarg_t rc;
  93.  
  94.     /*
  95.      * Someday, select() will do this for us.
  96.      * Just in case that day is now, and no one has
  97.      * changed this, we use a temporary.
  98.      */
  99.     if (tvp) {
  100.         (void) gettimeofday(&starttv, NULL);
  101.         endtv = *tvp;
  102.         s = &endtv;
  103.     } else
  104.         s = NULL;
  105. again:
  106.     if (!lastchar) {
  107.         if (!getchar_inprog)
  108.             getchar_inprog = async_send_2(1,CONSOLE_GETCHAR,0,0,&charcall);
  109.         if (!s)
  110.             async_wait_for(getchar_inprog, &rc);
  111.         else if (async_wait_timeout(getchar_inprog, &rc, s->tv_usec) == ETIMEOUT) {
  112.             tvp->tv_sec = 0;
  113.             tvp->tv_usec = 0;
  114.             return (0);
  115.         }
  116.         getchar_inprog = 0;
  117.         if (rc) {
  118.             stop("end of file, help");
  119.         }
  120.         lastchar = IPC_GET_ARG1(charcall);
  121.     }
  122.     if (tvp) {
  123.         /* since there is input, we may not have timed out */
  124.         (void) gettimeofday(&endtv, NULL);
  125.         TV_SUB(&endtv, &starttv);
  126.         TV_SUB(tvp, &endtv);    /* adjust *tvp by elapsed time */
  127.     }
  128.     return (1);
  129. }
  130.  
  131. /*
  132.  * `sleep' for the current turn time (using select).
  133.  * Eat any input that might be available.
  134.  */
  135. void
  136. tsleep(void)
  137. {
  138.     struct timeval tv;
  139.     char c;
  140.  
  141.     tv.tv_sec = 0;
  142.     tv.tv_usec = fallrate;
  143.     while (TV_POS(&tv))
  144.         if (rwait(&tv)) {
  145.             lastchar = '\0';
  146.         } else
  147.             break;
  148. }
  149.  
  150. /*
  151.  * getchar with timeout.
  152.  */
  153. int
  154. tgetchar(void)
  155. {
  156.     static struct timeval timeleft;
  157.     char c;
  158.  
  159.     /*
  160.      * Reset timeleft to fallrate whenever it is not positive.
  161.      * In any case, wait to see if there is any input.  If so,
  162.      * take it, and update timeleft so that the next call to
  163.      * tgetchar() will not wait as long.  If there is no input,
  164.      * make timeleft zero or negative, and return -1.
  165.      *
  166.      * Most of the hard work is done by rwait().
  167.      */
  168.     if (!TV_POS(&timeleft)) {
  169.         faster();   /* go faster */
  170.         timeleft.tv_sec = 0;
  171.         timeleft.tv_usec = fallrate;
  172.     }
  173.     if (!rwait(&timeleft))
  174.         return (-1);
  175.     c = lastchar;
  176.     lastchar = '\0';
  177.     return ((int)(unsigned char)c);
  178. }
  179.