* Copyright (c) 2007 The NetBSD Foundation, Inc.

/* $NetBSD: unicode.c,v 1.3 2015/06/21 14:09:47 maxv Exp $ */

/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Dieter Baron.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: unicode.c,v 1.3 2015/06/21 14:09:47 maxv Exp $");

#include <sys/null.h>

#include "unicode.h"

size_t
utf8_to_utf16(uint16_t *dst, size_t dst_len,
const char *src, size_t src_len,
int flags, int *errp)
{
const unsigned char *s;
size_t spos, dpos;
int error;
uint16_t c;

#define IS_CONT(c) (((c)&0xc0) == 0x80)

error = 0;
s = (const unsigned char *)src;
spos = dpos = 0;
while (spos < src_len) {
if (s[spos] < 0x80) {
c = s[spos++];
} else if ((flags & UNICODE_UTF8_LATIN1_FALLBACK)
&& (spos >= src_len || !IS_CONT(s[spos+1]))
&& s[spos]>=0xa0) {
/* not valid UTF-8, assume ISO 8859-1 */
c = s[spos++];
} else if (s[spos] < 0xc0 || s[spos] >= 0xf5) {
/* continuation byte without lead byte
* or lead byte for codepoint above 0x10ffff */
error++;
spos++;
continue;
} else if (s[spos] < 0xe0) {
if (spos >= src_len || !IS_CONT(s[spos+1])) {
spos++;
error++;
continue;
}
c = ((s[spos] & 0x3f) << 6) | (s[spos+1] & 0x3f);
spos += 2;
if (c < 0x80) {
/* overlong encoding */
error++;
continue;
}
} else if (s[spos] < 0xf0) {
if (spos >= src_len-2 ||
!IS_CONT(s[spos+1]) || !IS_CONT(s[spos+2])) {
spos++;
error++;
continue;
}
c = ((s[spos] & 0x0f) << 12) | ((s[spos+1] & 0x3f) << 6)
| (s[spos+2] & 0x3f);
spos += 3;
if (c < 0x800 || (c & 0xdf00) == 0xd800 ) {
/* overlong encoding or encoded surrogate */
error++;
continue;
}
} else {
uint32_t cc;
/* UTF-16 surrogate pair */

if (spos >= src_len-3 || !IS_CONT(s[spos+1])
|| !IS_CONT(s[spos+2]) || !IS_CONT(s[spos+3])) {
spos++;
error++;
continue;
}
cc = ((s[spos] & 0x03) << 18) | ((s[spos+1] & 0x3f) << 12)
| ((s[spos+2] & 0x3f) << 6) | (s[spos+3] & 0x3f);
spos += 4;
if (cc < 0x10000) {
/* overlong encoding */
error++;
continue;
}
if (dst && dpos < dst_len)
dst[dpos] = (0xd800 | ((cc-0x10000)>>10));
dpos++;
c = 0xdc00 | ((cc-0x10000) & 0x3ffff);
}

if (dst && dpos < dst_len)
dst[dpos] = c;
dpos++;
}

if (errp)
*errp = error;
return dpos;
#undef IS_CONT
}

size_t
utf16_to_utf8(char *dst, size_t dst_len,
const uint16_t *src, size_t src_len,
int flags, int *errp)
{
uint8_t spos, dpos;
int error;

#define CHECK_LENGTH(l) (dpos > dst_len-(l) ? dst=NULL : NULL)
#define ADD_BYTE(b) (dst ? dst[dpos] = (b) : 0, dpos++)

error = 0;
dpos = 0;
for (spos = 0; spos < src_len; spos++) {
if (src[spos] < 0x80) {
CHECK_LENGTH(1);
ADD_BYTE(src[spos]);
} else if (src[spos] < 0x800) {
CHECK_LENGTH(2);
ADD_BYTE(0xc0 | (src[spos]>>6));
ADD_BYTE(0x80 | (src[spos] & 0x3f));
} else if ((src[spos] & 0xdc00) == 0xd800) {
uint32_t c;
/* first surrogate */
if (spos == src_len - 1 || (src[spos] & 0xdc00) != 0xdc00) {
/* no second surrogate present */
error++;
continue;
}
spos++;
CHECK_LENGTH(4);
c = (((src[spos]&0x3ff) << 10) | (src[spos+1]&0x3ff)) + 0x10000;
ADD_BYTE(0xf0 | (c>>18));
ADD_BYTE(0x80 | ((c>>12) & 0x3f));
ADD_BYTE(0x80 | ((c>>6) & 0x3f));
ADD_BYTE(0x80 | (c & 0x3f));
} else if ((src[spos] & 0xdc00) == 0xdc00) {
/* second surrogate without preceding first surrogate */
error++;
} else {
CHECK_LENGTH(3);
ADD_BYTE(0xe0 | src[spos]>>12);
ADD_BYTE(0x80 | ((src[spos]>>6) & 0x3f));
ADD_BYTE(0x80 | (src[spos] & 0x3f));
}
}

if (errp)
*errp = error;
return dpos;
#undef ADD_BYTE
#undef CHECK_LENGTH
}