/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1995-1998 by Sun Microsystems, Inc.
 * All rights reserved.
 */

/* LINTLIBRARY */

/*
 * unctrl.c
 *
 * XCurses Library
 *
 * Copyright 1990, 1995 by Mortice Kern Systems Inc.  All rights reserved.
 *
 */

#if M_RCSID
#ifndef lint
static char rcsID[] =
"$Header: /team/ps/sun_xcurses/archive/local_changes/xcurses/src/lib/"
"libxcurses/src/libc/xcurses/rcs/unctrl.c 1.3 1998/05/29 15:58:55 "
"cbates Exp $";
#endif
#endif

#include <private.h>
#include <limits.h>
#include <ctype.h>

static const char *carat[] = {
        "^?",
        "^@",
        "^A",
        "^B",
        "^C",
        "^D",
        "^E",
        "^F",
        "^G",
        "^H",
        "^I",
        "^J",
        "^K",
        "^L",
        "^M",
        "^N",
        "^O",
        "^P",
        "^Q",
        "^R",
        "^S",
        "^T",
        "^U",
        "^V",
        "^W",
        "^X",
        "^Y",
        "^Z",
        "^[",
        "^\\",
        "^]",
        "^^",
        "^_"
};

char *
unctrl(chtype ch)
{
        char    *str;
        int     c, msb;
        static char     chr[5];


        /* Map wide character to a wide string. */
        c = (int)(ch & A_CHARTEXT);
        msb = 1 << (CHAR_BIT-1);

        if (c & ~((1 << CHAR_BIT) - 1)) {
                /* Only know about single-byte characters I guess ... */
                return (NULL);
        }
        if (iscntrl(c)) {
                /* ASCII DEL */
                if (c == 127)
                        return ((char *)carat[0]);

                /* ASCII control codes. */
                if (0 <= c && c < 32)
                        return ((char *)carat[c+1]);

                /* Something we don't know what to do with. */
                return (NULL);
        } else if (c & msb) {
                /* Meta key notation if high bit is set on character. */
                c &= ~msb;

                chr[0] = 'M';
                chr[1] = '-';

                if (iscntrl(c)) {
                        str = (char *) unctrl(c);
                        chr[2] = *str++;
                        chr[3] = *str;
                        chr[4] = '\0';
                } else {
                        chr[2] = (char)c;
                        chr[3] = '\0';
                }
        } else {
                /* Return byte as is. */
                chr[0] = (char)c;
                chr[1] = '\0';
        }

        return (chr);
}