/*-
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Paul Borman at Krystal Technologies.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)utf2.c	8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */

#include <rune.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

rune_t	_UTF2_sgetrune(const char *, size_t, char const **);
int	_UTF2_sputrune(rune_t, char *, size_t, char **);

static int _utf_count[16] = {
	1, 1, 1, 1, 1, 1, 1, 1,
	0, 0, 0, 0, 2, 2, 3, 0,
};

int
_UTF2_init(rl)
	_RuneLocale *rl;
{
	rl->sgetrune = _UTF2_sgetrune;
	rl->sputrune = _UTF2_sputrune;
	_CurrentRuneLocale = rl;
	__mb_cur_max = 3;
	return (0);
}

rune_t
_UTF2_sgetrune(string, n, result)
	const char *string;
	size_t n;
	char const **result;
{
	int c;

	if (n < 1 || (c = _utf_count[(*string >> 4) & 0xf]) > n) {
		if (result)
			*result = string;
		return (_INVALID_RUNE);
	}
	switch (c) {
	case 1:
		if (result)
			*result = string + 1;
		return (*string & 0xff);
	case 2:
		if ((string[1] & 0xC0) != 0x80)
			goto encoding_error;
		if (result)
			*result = string + 2;
		return (((string[0] & 0x1F) << 6) | (string[1] & 0x3F));
	case 3:
		if ((string[1] & 0xC0) != 0x80 || (string[2] & 0xC0) != 0x80)
			goto encoding_error;
		if (result)
			*result = string + 3;
		return (((string[0] & 0x1F) << 12) | ((string[1] & 0x3F) << 6)
		    | (string[2] & 0x3F));
	default:
encoding_error:	if (result)
			*result = string + 1;
		return (_INVALID_RUNE);
	}
}

int
_UTF2_sputrune(c, string, n, result)
	rune_t c;
	char *string, **result;
	size_t n;
{
	if (c & 0xF800) {
		if (n >= 3) {
			if (string) {
				string[0] = 0xE0 | ((c >> 12) & 0x0F);
				string[1] = 0x80 | ((c >> 6) & 0x3F);
				string[2] = 0x80 | ((c) & 0x3F);
			}
			if (result)
				*result = string + 3;
		} else
			if (result)
				*result = NULL;

		return (3);
	} else
		if (c & 0x0780) {
			if (n >= 2) {
				if (string) {
					string[0] = 0xC0 | ((c >> 6) & 0x1F);
					string[1] = 0x80 | ((c) & 0x3F);
				}
				if (result)
					*result = string + 2;
			} else
				if (result)
					*result = NULL;
			return (2);
		} else {
			if (n >= 1) {
				if (string)
					string[0] = c;
				if (result)
					*result = string + 1;
			} else
				if (result)
					*result = NULL;
			return (1);
		}
}