source: bootcd/isolinux/syslinux-6.03/gpxe/src/hci/mucurses/kb.c

#include <curses.h>
#include <stddef.h>
#include <unistd.h>
#include "mucurses.h"

/** @file
 *
 * MuCurses keyboard input handling functions
 */

#define INPUT_DELAY             200 // half-blocking delay timer resolution (ms)
#define INPUT_DELAY_TIMEOUT     1000 // half-blocking delay timeout

int m_delay; /* 
                < 0 : blocking read
                0   : non-blocking read
                > 0 : timed blocking read
             */
bool m_echo;
bool m_cbreak;

static int _wgetc ( WINDOW *win ) {
        int timer, c;

        if ( win == NULL )
                return ERR;

        timer = INPUT_DELAY_TIMEOUT;
        while ( ! win->scr->peek( win->scr ) ) {
                if ( m_delay == 0 ) // non-blocking read
                        return ERR;
                if ( timer > 0 ) {  // time-limited blocking read
                        if ( m_delay > 0 )
                                timer -= INPUT_DELAY;
                        mdelay( INPUT_DELAY );
                } else { return ERR; } // non-blocking read
        }

        c = win->scr->getc( win->scr );

        if ( m_echo && ( c >= 32 && c <= 126 ) ) // printable ASCII characters
                _wputch( win, (chtype) ( c | win->attrs ), WRAP );

        return c;
}

/**
 * Pop a character from the FIFO into a window
 *
 * @v *win      window in which to echo input
 * @ret c       char from input stream
 */
int wgetch ( WINDOW *win ) {
        int c;

        c = _wgetc( win );

        if ( m_echo ) {
                if ( c >= KEY_MIN ) {
                        switch(c) {
                        case KEY_LEFT :
                        case KEY_BACKSPACE :
                                _wcursback( win );
                                wdelch( win );
                                break;
                        default :
                                beep();
                                break;
                        }
                } else {
                        _wputch( win, (chtype)( c | win->attrs ), WRAP );
                }
        }

        return c;
}

/**
 * Read at most n characters from the FIFO into a window
 *
 * @v *win      window in which to echo input
 * @v *str      pointer to string in which to store result
 * @v n         maximum number of characters to read into string (inc. NUL)
 * @ret rc      return status code
 */
int wgetnstr ( WINDOW *win, char *str, int n ) {
        char *_str;
        int c;

        if ( n == 0 ) {
                str = '\0';
                return OK;
        }

        _str = str;

        while ( ( c = _wgetc( win ) ) != ERR ) {
                /* termination enforcement - don't let us go past the
                   end of the allocated buffer... */
                if ( n == 0 && ( c >= 32 && c <= 126 ) ) {
                        _wcursback( win );
                        wdelch( win );
                } else {
                        if ( c >= KEY_MIN ) {
                                switch(c) {
                                case KEY_LEFT :
                                case KEY_BACKSPACE :
                                        _wcursback( win );
                                        wdelch( win );
                                        break;
                                case KEY_ENTER :
                                        *_str = '\0';
                                        return OK;
                                default :
                                        beep();
                                        break;
                                }
                        }
                        if ( c >= 32 && c <= 126 ) {
                                *(_str++) = c; n--;
                        }
                }
        }

        return ERR;
}


/**
 *
 */
int echo ( void ) {
        m_echo = TRUE;
        return OK;
}

/**
 *
 */
int noecho ( void ) {
        m_echo = FALSE;
        return OK;
}