1 /* $OpenBSD: input.c,v 1.18 2016/08/27 02:02:44 guenther 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/time.h> 43 #include <errno.h> 44 #include <poll.h> 45 #include <unistd.h> 46 47 #include "input.h" 48 #include "tetris.h" 49 50 /* return true iff the given timeval is positive */ 51 #define TV_POS(tv) \ 52 ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0)) 53 54 /* subtract timeval `sub' from `res' */ 55 #define TV_SUB(res, sub) \ 56 (res)->tv_sec -= (sub)->tv_sec; \ 57 (res)->tv_usec -= (sub)->tv_usec; \ 58 if ((res)->tv_usec < 0) { \ 59 (res)->tv_usec += 1000000; \ 60 (res)->tv_sec--; \ 61 } 62 63 /* 64 * Do a `read wait': poll for reading from stdin, with timeout *tvp. 65 * On return, modify *tvp to reflect the amount of time spent waiting. 66 * It will be positive only if input appeared before the time ran out; 67 * otherwise it will be zero or perhaps negative. 68 * 69 * If tvp is nil, wait forever, but return if poll is interrupted. 70 * 71 * Return 0 => no input, 1 => can read() from stdin 72 */ 73 int 74 rwait(struct timeval *tvp) 75 { 76 int timo = INFTIM; 77 struct timeval starttv, endtv; 78 struct pollfd pfd[1]; 79 80 #define NILTZ ((struct timezone *)0) 81 82 if (tvp) { 83 (void) gettimeofday(&starttv, NILTZ); 84 endtv = *tvp; 85 timo = endtv.tv_sec * 1000 + endtv.tv_usec / 1000; 86 } 87 again: 88 pfd[0].fd = STDIN_FILENO; 89 pfd[0].events = POLLIN; 90 switch (poll(pfd, 1, timo)) { 91 case -1: 92 if (tvp == 0) 93 return (-1); 94 if (errno == EINTR) 95 goto again; 96 stop("poll failed, help"); 97 98 case 0: /* timed out */ 99 tvp->tv_sec = 0; 100 tvp->tv_usec = 0; 101 return (0); 102 } 103 if (tvp) { 104 /* since there is input, we may not have timed out */ 105 (void) gettimeofday(&endtv, NILTZ); 106 TV_SUB(&endtv, &starttv); 107 TV_SUB(tvp, &endtv); /* adjust *tvp by elapsed time */ 108 } 109 return (1); 110 } 111 112 /* 113 * `sleep' for the current turn time (using poll). 114 * Eat any input that might be available. 115 */ 116 void 117 tsleep(void) 118 { 119 struct timeval tv; 120 char c; 121 122 tv.tv_sec = 0; 123 tv.tv_usec = fallrate; 124 while (TV_POS(&tv)) 125 if (rwait(&tv) && read(STDIN_FILENO, &c, 1) != 1) 126 break; 127 } 128 129 /* 130 * getchar with timeout. 131 */ 132 int 133 tgetchar(void) 134 { 135 static struct timeval timeleft; 136 char c; 137 138 /* 139 * Reset timeleft to fallrate whenever it is not positive. 140 * In any case, wait to see if there is any input. If so, 141 * take it, and update timeleft so that the next call to 142 * tgetchar() will not wait as long. If there is no input, 143 * make timeleft zero or negative, and return -1. 144 * 145 * Most of the hard work is done by rwait(). 146 */ 147 if (!TV_POS(&timeleft)) { 148 faster(); /* go faster */ 149 timeleft.tv_sec = 0; 150 timeleft.tv_usec = fallrate; 151 } 152 if (!rwait(&timeleft)) 153 return (-1); 154 if (read(STDIN_FILENO, &c, 1) != 1) 155 stop("end of file, help"); 156 return ((int)(unsigned char)c); 157 } 158