1 /* $NetBSD: input.c,v 1.10 2006/03/19 00:50:28 christos 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 if (tvp) { 104 tvp->tv_sec = 0; 105 tvp->tv_usec = 0; 106 } 107 return (0); 108 } 109 if (tvp) { 110 /* since there is input, we may not have timed out */ 111 (void) gettimeofday(&endtv, NILTZ); 112 TV_SUB(&endtv, &starttv); 113 TV_SUB(tvp, &endtv); /* adjust *tvp by elapsed time */ 114 } 115 return (1); 116 } 117 118 /* 119 * `sleep' for the current turn time. 120 * Eat any input that might be available. 121 */ 122 void 123 tsleep() 124 { 125 struct timeval tv; 126 char c; 127 128 tv.tv_sec = 0; 129 tv.tv_usec = fallrate; 130 while (TV_POS(&tv)) 131 if (rwait(&tv) && read(0, &c, 1) != 1) 132 break; 133 } 134 135 /* 136 * getchar with timeout. 137 */ 138 int 139 tgetchar() 140 { 141 static struct timeval timeleft; 142 char c; 143 144 /* 145 * Reset timeleft to fallrate whenever it is not positive. 146 * In any case, wait to see if there is any input. If so, 147 * take it, and update timeleft so that the next call to 148 * tgetchar() will not wait as long. If there is no input, 149 * make timeleft zero or negative, and return -1. 150 * 151 * Most of the hard work is done by rwait(). 152 */ 153 if (!TV_POS(&timeleft)) { 154 faster(); /* go faster */ 155 timeleft.tv_sec = 0; 156 timeleft.tv_usec = fallrate; 157 } 158 if (!rwait(&timeleft)) 159 return (-1); 160 if (read(0, &c, 1) != 1) 161 stop("end of file, help"); 162 return ((int)(unsigned char)c); 163 } 164