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awaitkey.c revision 1.1 
      1 /*	$NetBSD: awaitkey.c,v 1.1 2013/01/21 11:58:12 tsutsui Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 Izumi Tsutsui.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include <lib/libkern/libkern.h>
     28 #include <luna68k/stand/boot/samachdep.h>
     29 
     30 static void print_countdown(const char *, int);
     31 
     32 #define FMTLEN	40
     33 
     34 static void
     35 print_countdown(const char *pfmt, int n)
     36 {
     37 	int len, i;
     38 	char fmtbuf[FMTLEN];
     39 
     40 	len = snprintf(fmtbuf, FMTLEN, pfmt, n);
     41 	printf("%s", fmtbuf);
     42 	for (i = 0; i < len; i++)
     43 		putchar('\b');
     44 }
     45 
     46 /*
     47  * awaitkey(const char *pfmt, int timeout, bool tell)
     48  *
     49  * Wait timeout seconds until any input from stdin.
     50  * print countdown message using "pfmt" if tell is true.
     51  * Requires tgetchar(), which returns 0 if there is no input.
     52  */
     53 char
     54 awaitkey(const char *pfmt, int timeout, bool tell)
     55 {
     56 	uint32_t otick;
     57 	char c = 0;
     58 
     59 	if (timeout <= 0)
     60 		goto out;
     61 
     62 	if (tell)
     63 		print_countdown(pfmt, timeout);
     64 
     65 	otick = tick;
     66 
     67 	for (;;) {
     68 		c = tgetchar();
     69 		if (c != 0)
     70 			break;
     71 		if (tick - otick >= hz) {
     72 			otick = tick;
     73 			if (--timeout == 0)
     74 				break;
     75 			if (tell)
     76 				print_countdown(pfmt, timeout);
     77 		}
     78 	}
     79 
     80  out:
     81 	if (tell) {
     82 		printf(pfmt, 0);
     83 		printf("\n");
     84 	}
     85 	return c;
     86 }
     87