1 /*- 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek and Darren F. Provine. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)input.c 8.1 (Berkeley) 5/31/93 37 */ 38 39 /* 40 * Tetris input. 41 */ 42 43 #include <sys/types.h> 44 #include <sys/time.h> 45 46 #include <errno.h> 47 #include <unistd.h> 48 49 #include "input.h" 50 #include "tetris.h" 51 52 /* return true iff the given timeval is positive */ 53 #define TV_POS(tv) \ 54 ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0)) 55 56 /* subtract timeval `sub' from `res' */ 57 #define TV_SUB(res, sub) \ 58 (res)->tv_sec -= (sub)->tv_sec; \ 59 (res)->tv_usec -= (sub)->tv_usec; \ 60 if ((res)->tv_usec < 0) { \ 61 (res)->tv_usec += 1000000; \ 62 (res)->tv_sec--; \ 63 } 64 65 /* 66 * Do a `read wait': select for reading from stdin, with timeout *tvp. 67 * On return, modify *tvp to reflect the amount of time spent waiting. 68 * It will be positive only if input appeared before the time ran out; 69 * otherwise it will be zero or perhaps negative. 70 * 71 * If tvp is nil, wait forever, but return if select is interrupted. 72 * 73 * Return 0 => no input, 1 => can read() from stdin 74 */ 75 int 76 rwait(tvp) 77 register struct timeval *tvp; 78 { 79 int i; 80 struct timeval starttv, endtv, *s; 81 extern int errno; 82 #define NILTZ ((struct timezone *)0) 83 84 /* 85 * Someday, select() will do this for us. 86 * Just in case that day is now, and no one has 87 * changed this, we use a temporary. 88 */ 89 if (tvp) { 90 (void) gettimeofday(&starttv, NILTZ); 91 endtv = *tvp; 92 s = &endtv; 93 } else 94 s = 0; 95 again: 96 i = 1; 97 switch (select(1, (fd_set *)&i, (fd_set *)0, (fd_set *)0, s)) { 98 99 case -1: 100 if (tvp == 0) 101 return (-1); 102 if (errno == EINTR) 103 goto again; 104 stop("select failed, help"); 105 /* NOTREACHED */ 106 107 case 0: /* timed out */ 108 tvp->tv_sec = 0; 109 tvp->tv_usec = 0; 110 return (0); 111 } 112 if (tvp) { 113 /* since there is input, we may not have timed out */ 114 (void) gettimeofday(&endtv, NILTZ); 115 TV_SUB(&endtv, &starttv); 116 TV_SUB(tvp, &endtv); /* adjust *tvp by elapsed time */ 117 } 118 return (1); 119 } 120 121 /* 122 * `sleep' for the current turn time (using select). 123 * Eat any input that might be available. 124 */ 125 void 126 tsleep() 127 { 128 struct timeval tv; 129 char c; 130 131 tv.tv_sec = 0; 132 tv.tv_usec = fallrate; 133 while (TV_POS(&tv)) 134 if (rwait(&tv) && read(0, &c, 1) != 1) 135 break; 136 } 137 138 /* 139 * Eat up any input (used at end of game). 140 */ 141 void 142 eat_input() 143 { 144 struct timeval tv; 145 char c; 146 147 do { 148 tv.tv_sec = tv.tv_usec = 0; 149 } while (rwait(&tv) && read(0, &c, 1) == 1); 150 } 151 152 /* 153 * getchar with timeout. 154 */ 155 int 156 tgetchar() 157 { 158 static struct timeval timeleft; 159 char c; 160 161 /* 162 * Reset timeleft to fallrate whenever it is not positive. 163 * In any case, wait to see if there is any input. If so, 164 * take it, and update timeleft so that the next call to 165 * tgetchar() will not wait as long. If there is no input, 166 * make timeleft zero or negative, and return -1. 167 * 168 * Most of the hard work is done by rwait(). 169 */ 170 if (!TV_POS(&timeleft)) { 171 faster(); /* go faster */ 172 timeleft.tv_sec = 0; 173 timeleft.tv_usec = fallrate; 174 } 175 if (!rwait(&timeleft)) 176 return (-1); 177 if (read(0, &c, 1) != 1) 178 stop("end of file, help"); 179 return ((int)(unsigned char)c); 180 } 181