com32/lib/sys/line_input.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.
 *
 * ----------------------------------------------------------------------- */

/*
 * line_input.c
 *
 * Line-oriented input discupline
 */

#include "file.h"
#include <errno.h>
#include <syslinux/idle.h>

ssize_t __line_input(struct file_info * fp, char *buf, size_t bufsize,
		     ssize_t(*get_char) (struct file_info *, void *, size_t))
{
    size_t n = 0;
    char ch;
    int rv;
    ssize_t(*const Write) (struct file_info *, const void *, size_t) =
	fp->oop->write;

    for (;;) {
	rv = get_char(fp, &ch, 1);

	if (rv != 1) {
	    syslinux_idle();
	    continue;
	}

	switch (ch) {
	case '\n':		/* Ignore incoming linefeed */
	    break;

	case '\r':
	    *buf = '\n';
	    Write(fp, "\n", 1);
	    return n + 1;

	case '\b':
	    if (n > 0) {
		n--;
		buf--;
		Write(fp, "\b \b", 3);
	    }
	    break;

	case '\x15':		/* Ctrl-U */
	    while (n) {
		n--;
		buf--;
		Write(fp, "\b \b", 3);
	    }
	    break;

	default:
	    if (n < bufsize - 1) {
		*buf = ch;
		Write(fp, buf, 1);
		n++;
		buf++;
	    }
	    break;
	}
    }
}