1 /* $NetBSD: input.c,v 1.4 1999/01/03 02:00:17 hubertf Exp $ */ 2 3 /*- 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek and Darren F. Provine. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)input.c 8.1 (Berkeley) 5/31/93 39 */ 40 41 /* 42 * Tetris input. 43 */ 44 45 #include <sys/types.h> 46 #include <sys/time.h> 47 48 #include <errno.h> 49 #include <unistd.h> 50 51 #include "input.h" 52 #include "tetris.h" 53 54 /* return true iff the given timeval is positive */ 55 #define TV_POS(tv) \ 56 ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0)) 57 58 /* subtract timeval `sub' from `res' */ 59 #define TV_SUB(res, sub) \ 60 (res)->tv_sec -= (sub)->tv_sec; \ 61 (res)->tv_usec -= (sub)->tv_usec; \ 62 if ((res)->tv_usec < 0) { \ 63 (res)->tv_usec += 1000000; \ 64 (res)->tv_sec--; \ 65 } 66 67 /* 68 * Do a `read wait': select for reading from stdin, with timeout *tvp. 69 * On return, modify *tvp to reflect the amount of time spent waiting. 70 * It will be positive only if input appeared before the time ran out; 71 * otherwise it will be zero or perhaps negative. 72 * 73 * If tvp is nil, wait forever, but return if select is interrupted. 74 * 75 * Return 0 => no input, 1 => can read() from stdin 76 */ 77 int 78 rwait(tvp) 79 register struct timeval *tvp; 80 { 81 int i; 82 struct timeval starttv, endtv, *s; 83 #define NILTZ ((struct timezone *)0) 84 85 /* 86 * Someday, select() will do this for us. 87 * Just in case that day is now, and no one has 88 * changed this, we use a temporary. 89 */ 90 if (tvp) { 91 (void) gettimeofday(&starttv, NILTZ); 92 endtv = *tvp; 93 s = &endtv; 94 } else 95 s = 0; 96 again: 97 i = 1; 98 switch (select(1, (fd_set *)&i, (fd_set *)0, (fd_set *)0, s)) { 99 100 case -1: 101 if (tvp == 0) 102 return (-1); 103 if (errno == EINTR) 104 goto again; 105 stop("select failed, help"); 106 /* NOTREACHED */ 107 108 case 0: /* timed out */ 109 tvp->tv_sec = 0; 110 tvp->tv_usec = 0; 111 return (0); 112 } 113 if (tvp) { 114 /* since there is input, we may not have timed out */ 115 (void) gettimeofday(&endtv, NILTZ); 116 TV_SUB(&endtv, &starttv); 117 TV_SUB(tvp, &endtv); /* adjust *tvp by elapsed time */ 118 } 119 return (1); 120 } 121 122 /* 123 * `sleep' for the current turn time (using select). 124 * Eat any input that might be available. 125 */ 126 void 127 tsleep() 128 { 129 struct timeval tv; 130 char c; 131 132 tv.tv_sec = 0; 133 tv.tv_usec = fallrate; 134 while (TV_POS(&tv)) 135 if (rwait(&tv) && read(0, &c, 1) != 1) 136 break; 137 } 138 139 /* 140 * getchar with timeout. 141 */ 142 int 143 tgetchar() 144 { 145 static struct timeval timeleft; 146 char c; 147 148 /* 149 * Reset timeleft to fallrate whenever it is not positive. 150 * In any case, wait to see if there is any input. If so, 151 * take it, and update timeleft so that the next call to 152 * tgetchar() will not wait as long. If there is no input, 153 * make timeleft zero or negative, and return -1. 154 * 155 * Most of the hard work is done by rwait(). 156 */ 157 if (!TV_POS(&timeleft)) { 158 faster(); /* go faster */ 159 timeleft.tv_sec = 0; 160 timeleft.tv_usec = fallrate; 161 } 162 if (!rwait(&timeleft)) 163 return (-1); 164 if (read(0, &c, 1) != 1) 165 stop("end of file, help"); 166 return ((int)(unsigned char)c); 167 } 168