1 /* $NetBSD: input.c,v 1.9 2003/08/07 09:37:47 agc 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)input.c 8.1 (Berkeley) 5/31/93 35 */ 36 37 /* 38 * Tetris input. 39 */ 40 41 #include <sys/types.h> 42 #include <sys/time.h> 43 #include <sys/poll.h> 44 45 #include <errno.h> 46 #include <unistd.h> 47 48 #include "input.h" 49 #include "tetris.h" 50 51 /* return true iff the given timeval is positive */ 52 #define TV_POS(tv) \ 53 ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0)) 54 55 /* subtract timeval `sub' from `res' */ 56 #define TV_SUB(res, sub) \ 57 (res)->tv_sec -= (sub)->tv_sec; \ 58 (res)->tv_usec -= (sub)->tv_usec; \ 59 if ((res)->tv_usec < 0) { \ 60 (res)->tv_usec += 1000000; \ 61 (res)->tv_sec--; \ 62 } 63 64 /* 65 * Do a `read wait': poll for reading from stdin, with timeout *tvp. 66 * On return, modify *tvp to reflect the amount of time spent waiting. 67 * It will be positive only if input appeared before the time ran out; 68 * otherwise it will be zero or perhaps negative. 69 * 70 * If tvp is nil, wait forever, but return if poll is interrupted. 71 * 72 * Return 0 => no input, 1 => can read() from stdin 73 */ 74 int 75 rwait(tvp) 76 struct timeval *tvp; 77 { 78 struct pollfd set[1]; 79 struct timeval starttv, endtv; 80 int timeout; 81 #define NILTZ ((struct timezone *)0) 82 83 if (tvp) { 84 (void) gettimeofday(&starttv, NILTZ); 85 endtv = *tvp; 86 timeout = tvp->tv_sec * 1000 + tvp->tv_usec / 1000; 87 } else 88 timeout = INFTIM; 89 again: 90 set[0].fd = STDIN_FILENO; 91 set[0].events = POLLIN; 92 switch (poll(set, 1, timeout)) { 93 94 case -1: 95 if (tvp == 0) 96 return (-1); 97 if (errno == EINTR) 98 goto again; 99 stop("poll failed, help"); 100 /* NOTREACHED */ 101 102 case 0: /* timed out */ 103 tvp->tv_sec = 0; 104 tvp->tv_usec = 0; 105 return (0); 106 } 107 if (tvp) { 108 /* since there is input, we may not have timed out */ 109 (void) gettimeofday(&endtv, NILTZ); 110 TV_SUB(&endtv, &starttv); 111 TV_SUB(tvp, &endtv); /* adjust *tvp by elapsed time */ 112 } 113 return (1); 114 } 115 116 /* 117 * `sleep' for the current turn time. 118 * Eat any input that might be available. 119 */ 120 void 121 tsleep() 122 { 123 struct timeval tv; 124 char c; 125 126 tv.tv_sec = 0; 127 tv.tv_usec = fallrate; 128 while (TV_POS(&tv)) 129 if (rwait(&tv) && read(0, &c, 1) != 1) 130 break; 131 } 132 133 /* 134 * getchar with timeout. 135 */ 136 int 137 tgetchar() 138 { 139 static struct timeval timeleft; 140 char c; 141 142 /* 143 * Reset timeleft to fallrate whenever it is not positive. 144 * In any case, wait to see if there is any input. If so, 145 * take it, and update timeleft so that the next call to 146 * tgetchar() will not wait as long. If there is no input, 147 * make timeleft zero or negative, and return -1. 148 * 149 * Most of the hard work is done by rwait(). 150 */ 151 if (!TV_POS(&timeleft)) { 152 faster(); /* go faster */ 153 timeleft.tv_sec = 0; 154 timeleft.tv_usec = fallrate; 155 } 156 if (!rwait(&timeleft)) 157 return (-1); 158 if (read(0, &c, 1) != 1) 159 stop("end of file, help"); 160 return ((int)(unsigned char)c); 161 } 162