Kbhit.h

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/*****************************************************************************
_kbhit() and _getch() for Linux/UNIX
Chris Giese <geezer@execpc.com> http://my.execpc.com/~geezer
Release date: ?
This code is public domain (no copyright).
You can do whatever you want with it.
*****************************************************************************/
/*
 *  Modified work: Copyright (c) 2016, SLikeSoft UG (haftungsbeschränkt)
 *
 *  This source code was modified by SLikeSoft. Modifications in this file are put under the public domain.
 *  Alternatively you are permitted to license the modifications under the MIT license, if you so desire. The
 *  license can be found in the license.txt file in the root directory of this source tree.
 */

#if defined(_WIN32)
#include <conio.h> /* _kbhit(), _getch() */

#else
#include <sys/time.h> /* struct timeval, select() */
/* ICANON, ECHO, TCSANOW, struct termios */
#include <termios.h> /* tcgetattr(), tcsetattr() */
#include <stdlib.h> /* atexit(), exit() */
#include <unistd.h> /* read() */
#include <stdio.h> /* printf() */
#include <string.h> /* memcpy */

static struct termios g_old_kbd_mode;
/*****************************************************************************
*****************************************************************************/
static void cooked(void)
{
    tcsetattr(0, TCSANOW, &g_old_kbd_mode);
}
/*****************************************************************************
*****************************************************************************/
static void raw(void)
{
    static char init;

    struct termios new_kbd_mode;

    if(init)
        return;
/* put keyboard (stdin, actually) in raw, unbuffered mode */
    tcgetattr(0, &g_old_kbd_mode);
    memcpy(&new_kbd_mode, &g_old_kbd_mode, sizeof(struct termios));
    new_kbd_mode.c_lflag &= ~(ICANON /*| ECHO */ );
    new_kbd_mode.c_cc[VTIME] = 0;
    new_kbd_mode.c_cc[VMIN] = 1;
    tcsetattr(0, TCSANOW, &new_kbd_mode);
/* when we exit, go back to normal, "cooked" mode */
    atexit(cooked);

    init = 1;
}
/*****************************************************************************
*****************************************************************************/
static int _kbhit(void)
{
    struct timeval timeout;
    fd_set read_handles;
    int status;

    raw();
/* check stdin (fd 0) for activity */
    FD_ZERO(&read_handles);
    FD_SET(0, &read_handles);
    timeout.tv_sec = timeout.tv_usec = 0;
    status = select(0 + 1, &read_handles, NULL, NULL, &timeout);
    if(status < 0)
    {
        printf("select() failed in _kbhit()\n");
        exit(1);
    }
    return status;
}
/*****************************************************************************
*****************************************************************************/
static int _getch(void)
{
    unsigned char temp;

    raw();
/* stdin = fd 0 */
    if(read(0, &temp, 1) != 1)
        return 0;
    return temp;
}
#endif