source: bootcd/isolinux/syslinux-6.03/com32/lib/sys/rawcon_read.c

/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
 *
 *   Permission is hereby granted, free of charge, to any person
 *   obtaining a copy of this software and associated documentation
 *   files (the "Software"), to deal in the Software without
 *   restriction, including without limitation the rights to use,
 *   copy, modify, merge, publish, distribute, sublicense, and/or
 *   sell copies of the Software, and to permit persons to whom
 *   the Software is furnished to do so, subject to the following
 *   conditions:
 *
 *   The above copyright notice and this permission notice shall
 *   be included in all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *   OTHER DEALINGS IN THE SOFTWARE.
 *
 * ----------------------------------------------------------------------- */

/*
 * rawcon_read.c
 *
 * Character-oriented reading from the console without echo;
 * this is a NONBLOCKING device.
 */

#include <errno.h>
#include <string.h>
#include <com32.h>
#include <core.h>
#include <minmax.h>
#include "file.h"

/* Global, since it's used by stdcon_read */
ssize_t __rawcon_read(struct file_info *fp, void *buf, size_t count)
{
    char *bufp = buf;
    size_t n = 0;
    static char hi = 0;
    static bool hi_key = false;

    (void)fp;

    while (n < count) {
        if (hi_key) {
            *bufp++ = hi;
            n++;
            hi_key = false;
            continue;
        }

        /* Poll */
        if (!pollchar())
            break;

        /* We have data, go get it */
        *bufp = getchar(&hi);
        if (!*bufp)
                hi_key = true;

        bufp++;
        n++;
    }

    return n;
}

const struct input_dev dev_rawcon_r = {
    .dev_magic = __DEV_MAGIC,
    .flags = __DEV_TTY | __DEV_INPUT,
    .fileflags = O_RDONLY,
    .read = __rawcon_read,
    .close = NULL,
    .open = NULL,
};