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79 lines
1.3 KiB
C
79 lines
1.3 KiB
C
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/*
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* lib/getkey.c - Get single characters from standard input
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*
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* Written 2011 by Werner Almesberger
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* Copyright 2011 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <termios.h>
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#include <errno.h>
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static struct termios old_term;
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static void restore_term(void)
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{
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if (tcsetattr(0, TCSAFLUSH, &old_term) < 0)
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perror("tcsetattr");
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}
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void get_key_init(void)
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{
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static int initialized = 0;
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struct termios term;
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if (initialized)
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return;
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initialized = 1;
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if (tcgetattr(0, &old_term) < 0) {
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perror("tcgetattr");
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exit(1);
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}
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term = old_term;
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cfmakeraw(&term);
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if (tcsetattr(0, TCSAFLUSH, &term) < 0) {
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perror("tcsetattr");
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exit(1);
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}
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atexit(restore_term);
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if (fcntl(0, F_SETFL, O_NONBLOCK) < 0) {
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perror("fcntl");
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exit(1);
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}
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}
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char get_key(void)
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{
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ssize_t got;
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char ch;
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get_key_init();
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got = read(0, &ch, 1);
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if (got == 1)
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return ch;
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if (got >= 0) {
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fprintf(stderr, "unexpected read() return value %d\n",
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(int) got);
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exit(1);
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}
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if (errno == EAGAIN)
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return 0;
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perror("read");
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exit(1);
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}
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