/* $FreeBSD: release/9.1.0/sys/fs/msdosfs/msdosfs_conv.c 230196 2012-01-16 05:15:13Z kevlo $ */
/*	$NetBSD: msdosfs_conv.c,v 1.25 1997/11/17 15:36:40 ws Exp $	*/

/*-
 * Copyright (C) 1995, 1997 Wolfgang Solfrank.
 * Copyright (C) 1995, 1997 TooLs GmbH.
 * All rights reserved.
 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
 *
 * 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 TooLs GmbH.
 * 4. The name of TooLs GmbH may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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.
 */
/*-
 * Written by Paul Popelka (paulp@uts.amdahl.com)
 *
 * You can do anything you want with this software, just don't say you wrote
 * it, and don't remove this notice.
 *
 * This software is provided "as is".
 *
 * The author supplies this software to be publicly redistributed on the
 * understanding that the author is not responsible for the correct
 * functioning of this software in any circumstances and is not liable for
 * any damages caused by this software.
 *
 * October 1992
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dirent.h>
#include <sys/iconv.h>
#include <sys/mount.h>

#include <fs/msdosfs/bpb.h>
#include <fs/msdosfs/direntry.h>
#include <fs/msdosfs/msdosfsmount.h>

extern struct iconv_functions *msdosfs_iconv;

static int mbsadjpos(const char **, size_t, size_t, int, int, void *handle);
static u_char * dos2unixchr(u_char *, const u_char **, size_t *, int, struct msdosfsmount *);
static u_int16_t unix2doschr(const u_char **, size_t *, struct msdosfsmount *);
static u_char * win2unixchr(u_char *, u_int16_t, struct msdosfsmount *);
static u_int16_t unix2winchr(const u_char **, size_t *, int, struct msdosfsmount *);

/*
 * 0 - character disallowed in long file name.
 * 1 - character should be replaced by '_' in DOS file name, 
 *     and generation number inserted.
 * 2 - character ('.' and ' ') should be skipped in DOS file name,
 *     and generation number inserted.
 */
static u_char
unix2dos[256] = {
/* iso8859-1 -> cp850 */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 00-07 */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 08-0f */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 10-17 */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 18-1f */
	2,    0x21, 0,    0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
	0x28, 0x29, 0,    1,    1,    0x2d, 2,    0,	/* 28-2f */
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
	0x38, 0x39, 0,    1,    0,    1,    0,    0,	/* 38-3f */
	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
	0x58, 0x59, 0x5a, 1,    0,    1,    0x5e, 0x5f,	/* 58-5f */
	0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 60-67 */
	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 68-6f */
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 70-77 */
	0x58, 0x59, 0x5a, 0x7b, 0,    0x7d, 0x7e, 0,	/* 78-7f */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 80-87 */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 88-8f */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 90-97 */
	0,    0,    0,    0,    0,    0,    0,    0,	/* 98-9f */
	0,    0xad, 0xbd, 0x9c, 0xcf, 0xbe, 0xdd, 0xf5,	/* a0-a7 */
	0xf9, 0xb8, 0xa6, 0xae, 0xaa, 0xf0, 0xa9, 0xee,	/* a8-af */
	0xf8, 0xf1, 0xfd, 0xfc, 0xef, 0xe6, 0xf4, 0xfa,	/* b0-b7 */
	0xf7, 0xfb, 0xa7, 0xaf, 0xac, 0xab, 0xf3, 0xa8,	/* b8-bf */
	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* c0-c7 */
	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* c8-cf */
	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0x9e,	/* d0-d7 */
	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0xe1,	/* d8-df */
	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* e0-e7 */
	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* e8-ef */
	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0xf6,	/* f0-f7 */
	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0x98,	/* f8-ff */
};

static u_char
dos2unix[256] = {
/* cp850 -> iso8859-1 */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 00-07 */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 08-0f */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 10-17 */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 18-1f */
	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,	/* 28-2f */
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,	/* 38-3f */
	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,	/* 58-5f */
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,	/* 60-67 */
	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,	/* 68-6f */
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,	/* 70-77 */
	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,	/* 78-7f */
	0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0, 0xe5, 0xe7,	/* 80-87 */
	0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5,	/* 88-8f */
	0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2, 0xfb, 0xf9,	/* 90-97 */
	0xff, 0xd6, 0xdc, 0xf8, 0xa3, 0xd8, 0xd7, 0x3f,	/* 98-9f */
	0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xaa, 0xba,	/* a0-a7 */
	0xbf, 0xae, 0xac, 0xbd, 0xbc, 0xa1, 0xab, 0xbb,	/* a8-af */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xc1, 0xc2, 0xc0,	/* b0-b7 */
	0xa9, 0x3f, 0x3f, 0x3f, 0x3f, 0xa2, 0xa5, 0x3f,	/* b8-bf */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xe3, 0xc3,	/* c0-c7 */
	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xa4,	/* c8-cf */
	0xf0, 0xd0, 0xca, 0xcb, 0xc8, 0x3f, 0xcd, 0xce,	/* d0-d7 */
	0xcf, 0x3f, 0x3f, 0x3f, 0x3f, 0xa6, 0xcc, 0x3f,	/* d8-df */
	0xd3, 0xdf, 0xd4, 0xd2, 0xf5, 0xd5, 0xb5, 0xfe,	/* e0-e7 */
	0xde, 0xda, 0xdb, 0xd9, 0xfd, 0xdd, 0xaf, 0x3f,	/* e8-ef */
	0xad, 0xb1, 0x3f, 0xbe, 0xb6, 0xa7, 0xf7, 0xb8,	/* f0-f7 */
	0xb0, 0xa8, 0xb7, 0xb9, 0xb3, 0xb2, 0x3f, 0x3f,	/* f8-ff */
};

static u_char
u2l[256] = {
/* tolower */
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 00-07 */
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 08-0f */
	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 10-17 */
	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 18-1f */
	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 20-27 */
	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 28-2f */
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 30-37 */
	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 38-3f */
	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 40-47 */
	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 48-4f */
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 50-57 */
	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 58-5f */
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 60-67 */
	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 68-6f */
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 70-77 */
	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 78-7f */
	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 80-87 */
	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 88-8f */
	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 90-97 */
	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 98-9f */
	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* a0-a7 */
	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* a8-af */
	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* b0-b7 */
	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* b8-bf */
	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* c0-c7 */
	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* c8-cf */
	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xd7, /* d0-d7 */
	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xdf, /* d8-df */
	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* e0-e7 */
	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* e8-ef */
	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* f0-f7 */
	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* f8-ff */
};

static u_char
l2u[256] = {
/* toupper */
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 00-07 */
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 08-0f */
	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 10-17 */
	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 18-1f */
	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 20-27 */
	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 28-2f */
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 30-37 */
	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 38-3f */
	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 40-47 */
	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 48-4f */
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 50-57 */
	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 58-5f */
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 60-67 */
	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 68-6f */
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 70-77 */
	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 78-7f */
	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 80-87 */
	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 88-8f */
	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 90-97 */
	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 98-9f */
	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* a0-a7 */
	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* a8-af */
	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* b0-b7 */
	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* b8-bf */
	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* c0-c7 */
	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* c8-cf */
	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xd7, /* d0-d7 */
	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xdf, /* d8-df */
	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* e0-e7 */
	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* e8-ef */
	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* f0-f7 */
	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* f8-ff */
};

/*
 * DOS filenames are made of 2 parts, the name part and the extension part.
 * The name part is 8 characters long and the extension part is 3
 * characters long.  They may contain trailing blanks if the name or
 * extension are not long enough to fill their respective fields.
 */

/*
 * Convert a DOS filename to a unix filename. And, return the number of
 * characters in the resulting unix filename excluding the terminating
 * null.
 */
int
dos2unixfn(dn, un, lower, pmp)
	u_char dn[11];
	u_char *un;
	int lower;
	struct msdosfsmount *pmp;
{
	size_t i;
	int thislong = 0;
	u_char *c, tmpbuf[5];

	/*
	 * If first char of the filename is SLOT_E5 (0x05), then the real
	 * first char of the filename should be 0xe5. But, they couldn't
	 * just have a 0xe5 mean 0xe5 because that is used to mean a freed
	 * directory slot. Another dos quirk.
	 */
	if (*dn == SLOT_E5)
		*dn = 0xe5;

	/*
	 * Copy the name portion into the unix filename string.
	 */
	for (i = 8; i > 0 && *dn != ' ';) {
		c = dos2unixchr(tmpbuf, (const u_char **)&dn, &i,
		    lower & LCASE_BASE, pmp);
		while (*c != '\0') {
			*un++ = *c++;
			thislong++;
		}
	}
	dn += i;

	/*
	 * Now, if there is an extension then put in a period and copy in
	 * the extension.
	 */
	if (*dn != ' ') {
		*un++ = '.';
		thislong++;
		for (i = 3; i > 0 && *dn != ' ';) {
			c = dos2unixchr(tmpbuf, (const u_char **)&dn, &i,
			    lower & LCASE_EXT, pmp);
			while (*c != '\0') {
				*un++ = *c++;
				thislong++;
			}
		}
	}
	*un++ = 0;

	return (thislong);
}

/*
 * Convert a unix filename to a DOS filename according to Win95 rules.
 * If applicable and gen is not 0, it is inserted into the converted
 * filename as a generation number.
 * Returns
 *	0 if name couldn't be converted
 *	1 if the converted name is the same as the original
 *	  (no long filename entry necessary for Win95)
 *	2 if conversion was successful
 *	3 if conversion was successful and generation number was inserted
 */
int
unix2dosfn(un, dn, unlen, gen, pmp)
	const u_char *un;
	u_char dn[12];
	size_t unlen;
	u_int gen;
	struct msdosfsmount *pmp;
{
	ssize_t i, j;
	int l;
	int conv = 1;
	const u_char *cp, *dp, *dp1;
	u_char gentext[6], *wcp;
	u_int16_t c;

	/*
	 * Fill the dos filename string with blanks. These are DOS's pad
	 * characters.
	 */
	for (i = 0; i < 11; i++)
		dn[i] = ' ';
	dn[11] = 0;

	/*
	 * The filenames "." and ".." are handled specially, since they
	 * don't follow dos filename rules.
	 */
	if (un[0] == '.' && unlen == 1) {
		dn[0] = '.';
		return gen <= 1;
	}
	if (un[0] == '.' && un[1] == '.' && unlen == 2) {
		dn[0] = '.';
		dn[1] = '.';
		return gen <= 1;
	}

	/*
	 * Filenames with only blanks and dots are not allowed!
	 */
	for (cp = un, i = unlen; --i >= 0; cp++)
		if (*cp != ' ' && *cp != '.')
			break;
	if (i < 0)
		return 0;


	/*
	 * Filenames with some characters are not allowed!
	 */
	for (cp = un, i = unlen; i > 0;)
		if (unix2doschr(&cp, (size_t *)&i, pmp) == 0)
			return 0;

	/*
	 * Now find the extension
	 * Note: dot as first char doesn't start extension
	 *	 and trailing dots and blanks are ignored
	 * Note(2003/7): It seems recent Windows has
	 *	 defferent rule than this code, that Windows
	 *	 ignores all dots before extension, and use all
	 * 	 chars as filename except for dots.
	 */
	dp = dp1 = 0;
	for (cp = un + 1, i = unlen - 1; --i >= 0;) {
		switch (*cp++) {
		case '.':
			if (!dp1)
				dp1 = cp;
			break;
		case ' ':
			break;
		default:
			if (dp1)
				dp = dp1;
			dp1 = 0;
			break;
		}
	}

	/*
	 * Now convert it (this part is for extension).
	 * As Windows XP do, if it's not ascii char,
	 * this function should return 2 or 3, so that checkng out Unicode name.
	 */
	if (dp) {
		if (dp1)
			l = dp1 - dp;
		else
			l = unlen - (dp - un);
		for (cp = dp, i = l, j = 8; i > 0 && j < 11; j++) {
			c = unix2doschr(&cp, (size_t *)&i, pmp);
			if (c & 0xff00) {
				dn[j] = c >> 8;
				if (++j < 11) {
					dn[j] = c;
					if (conv != 3)
						conv = 2;
					continue;
				} else {
					conv = 3;
					dn[j-1] = ' ';
					break;
				}
			} else {
				dn[j] = c;
			}
			if (((dn[j] & 0x80) || *(cp - 1) != dn[j]) && conv != 3)
				conv = 2;
			if (dn[j] == 1) {
				conv = 3;
				dn[j] = '_';
			}
			if (dn[j] == 2) {
				conv = 3;
				dn[j--] = ' ';
			}
		}
		if (i > 0)
			conv = 3;
		dp--;
	} else {
		for (dp = cp; *--dp == ' ' || *dp == '.';);
		dp++;
	}

	/*
	 * Now convert the rest of the name
	 */
	for (i = dp - un, j = 0; un < dp && j < 8; j++) {
		c = unix2doschr(&un, &i, pmp);
		if (c & 0xff00) {
			dn[j] = c >> 8;
			if (++j < 8) {
				dn[j] = c;
				if (conv != 3)
					conv = 2;
				continue;
			} else {
				conv = 3;
				dn[j-1] = ' ';
				break;
			}
		} else {
			dn[j] = c;
		}
		if (((dn[j] & 0x80) || *(un - 1) != dn[j]) && conv != 3)
			conv = 2;
		if (dn[j] == 1) {
			conv = 3;
			dn[j] = '_';
		}
		if (dn[j] == 2) {
			conv = 3;
			dn[j--] = ' ';
		}
	}
	if (un < dp)
		conv = 3;
	/*
	 * If we didn't have any chars in filename,
	 * generate a default
	 */
	if (!j)
		dn[0] = '_';

	/*
	 * If there wasn't any char dropped,
	 * there is no place for generation numbers
	 */
	if (conv != 3) {
		if (gen > 1)
			conv = 0;
		goto done;
	}

	/*
	 * Now insert the generation number into the filename part
	 */
	if (gen == 0)
		goto done;
	for (wcp = gentext + sizeof(gentext); wcp > gentext && gen; gen /= 10)
		*--wcp = gen % 10 + '0';
	if (gen) {
		conv = 0;
		goto done;
	}
	for (i = 8; dn[--i] == ' ';);
	i++;
	if (gentext + sizeof(gentext) - wcp + 1 > 8 - i)
		i = 8 - (gentext + sizeof(gentext) - wcp + 1);
	/*
	 * Correct posision to where insert the generation number
	 */
	cp = dn;
	i -= mbsadjpos((const char**)&cp, i, unlen, 1, pmp->pm_flags, pmp->pm_d2u);

	dn[i++] = '~';
	while (wcp < gentext + sizeof(gentext))
		dn[i++] = *wcp++;

	/*
	 * Tail of the filename should be space
	 */
	while (i < 8)
		dn[i++] = ' ';
	conv = 3;

done:
	/*
	 * The first character cannot be E5,
	 * because that means a deleted entry
	 */
	if (dn[0] == 0xe5)
		dn[0] = SLOT_E5;

	return conv;
}

/*
 * Create a Win95 long name directory entry
 * Note: assumes that the filename is valid,
 *	 i.e. doesn't consist solely of blanks and dots
 */
int
unix2winfn(un, unlen, wep, cnt, chksum, pmp)
	const u_char *un;
	size_t unlen;
	struct winentry *wep;
	int cnt;
	int chksum;
	struct msdosfsmount *pmp;
{
	u_int8_t *wcp;
	int i, end;
	u_int16_t code;

	/*
	 * Drop trailing blanks and dots
	 */
	unlen = winLenFixup(un, unlen);

	/*
	 * Cut *un for this slot
	 */
	unlen = mbsadjpos((const char **)&un, unlen, (cnt - 1) * WIN_CHARS, 2,
			  pmp->pm_flags, pmp->pm_u2w);

	/*
	 * Initialize winentry to some useful default
	 */
	for (wcp = (u_int8_t *)wep, i = sizeof(*wep); --i >= 0; *wcp++ = 0xff);
	wep->weCnt = cnt;
	wep->weAttributes = ATTR_WIN95;
	wep->weReserved1 = 0;
	wep->weChksum = chksum;
	wep->weReserved2 = 0;

	/*
	 * Now convert the filename parts
	 */
	end = 0;
	for (wcp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0 && !end;) {
		code = unix2winchr(&un, &unlen, 0, pmp);
		*wcp++ = code;
		*wcp++ = code >> 8;
		if (!code)
			end = WIN_LAST;
	}
	for (wcp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0 && !end;) {
		code = unix2winchr(&un, &unlen, 0, pmp);
		*wcp++ = code;
		*wcp++ = code >> 8;
		if (!code)
			end = WIN_LAST;
	}
	for (wcp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0 && !end;) {
		code = unix2winchr(&un, &unlen, 0, pmp);
		*wcp++ = code;
		*wcp++ = code >> 8;
		if (!code)
			end = WIN_LAST;
	}
	if (*un == '\0')
		end = WIN_LAST;
	wep->weCnt |= end;
	return !end;
}

/*
 * Compare our filename to the one in the Win95 entry
 * Returns the checksum or -1 if no match
 */
int
winChkName(nbp, un, unlen, chksum, pmp)
	struct mbnambuf *nbp;
	const u_char *un;
	size_t unlen;
	int chksum;
	struct msdosfsmount *pmp;
{
	size_t len;
	u_int16_t c1, c2;
	u_char *np;
	struct dirent dirbuf;

	/*
	 * We already have winentry in *nbp.
	 */
	if (!mbnambuf_flush(nbp, &dirbuf) || dirbuf.d_namlen == 0)
		return -1;

#ifdef MSDOSFS_DEBUG
	printf("winChkName(): un=%s:%d,d_name=%s:%d\n", un, unlen,
							dirbuf.d_name,
							dirbuf.d_namlen);
#endif

	/*
	 * Compare the name parts
	 */
	len = dirbuf.d_namlen;
	if (unlen != len)
		return -2;

	for (np = dirbuf.d_name; unlen > 0 && len > 0;) {
		/*
		 * Comparison must be case insensitive, because FAT disallows
		 * to look up or create files in case sensitive even when
		 * it's a long file name.
		 */
		c1 = unix2winchr((const u_char **)&np, &len, LCASE_BASE, pmp);
		c2 = unix2winchr(&un, &unlen, LCASE_BASE, pmp);
		if (c1 != c2)
			return -2;
	}
	return chksum;
}

/*
 * Convert Win95 filename to dirbuf.
 * Returns the checksum or -1 if impossible
 */
int
win2unixfn(nbp, wep, chksum, pmp)
	struct mbnambuf *nbp;
	struct winentry *wep;
	int chksum;
	struct msdosfsmount *pmp;
{
	u_char *c, tmpbuf[5];
	u_int8_t *cp;
	u_int8_t *np, name[WIN_CHARS * 3 + 1];
	u_int16_t code;
	int i;

	if ((wep->weCnt&WIN_CNT) > howmany(WIN_MAXLEN, WIN_CHARS)
	    || !(wep->weCnt&WIN_CNT))
		return -1;

	/*
	 * First compare checksums
	 */
	if (wep->weCnt&WIN_LAST) {
		chksum = wep->weChksum;
	} else if (chksum != wep->weChksum)
		chksum = -1;
	if (chksum == -1)
		return -1;

	/*
	 * Convert the name parts
	 */
	np = name;
	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
		code = (cp[1] << 8) | cp[0];
		switch (code) {
		case 0:
			*np = '\0';
			mbnambuf_write(nbp, name, (wep->weCnt & WIN_CNT) - 1);
			return chksum;
		case '/':
			*np = '\0';
			return -1;
		default:
			c = win2unixchr(tmpbuf, code, pmp);
			while (*c != '\0')
				*np++ = *c++;
			break;
		}
		cp += 2;
	}
	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
		code = (cp[1] << 8) | cp[0];
		switch (code) {
		case 0:
			*np = '\0';
			mbnambuf_write(nbp, name, (wep->weCnt & WIN_CNT) - 1);
			return chksum;
		case '/':
			*np = '\0';
			return -1;
		default:
			c = win2unixchr(tmpbuf, code, pmp);
			while (*c != '\0')
				*np++ = *c++;
			break;
		}
		cp += 2;
	}
	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
		code = (cp[1] << 8) | cp[0];
		switch (code) {
		case 0:
			*np = '\0';
			mbnambuf_write(nbp, name, (wep->weCnt & WIN_CNT) - 1);
			return chksum;
		case '/':
			*np = '\0';
			return -1;
		default:
			c = win2unixchr(tmpbuf, code, pmp);
			while (*c != '\0')
				*np++ = *c++;
			break;
		}
		cp += 2;
	}
	*np = '\0';
	mbnambuf_write(nbp, name, (wep->weCnt & WIN_CNT) - 1);
	return chksum;
}

/*
 * Compute the unrolled checksum of a DOS filename for Win95 LFN use.
 */
u_int8_t
winChksum(u_int8_t *name)
{
	int i;
	u_int8_t s;

	for (s = 0, i = 11; --i >= 0; s += *name++)
		s = (s << 7)|(s >> 1);
	return (s);
}

/*
 * Determine the number of slots necessary for Win95 names
 */
int
winSlotCnt(un, unlen, pmp)
	const u_char *un;
	size_t unlen;
	struct msdosfsmount *pmp;
{
	size_t wlen;
	char wn[WIN_MAXLEN * 2 + 1], *wnp;

	unlen = winLenFixup(un, unlen);

	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
		wlen = WIN_MAXLEN * 2;
		wnp = wn;
		msdosfs_iconv->conv(pmp->pm_u2w, (const char **)&un, &unlen, &wnp, &wlen);
		if (unlen > 0)
			return 0;
		return howmany(WIN_MAXLEN - wlen/2, WIN_CHARS);
	}

	if (unlen > WIN_MAXLEN)
		return 0;
	return howmany(unlen, WIN_CHARS);
}

/*
 * Determine the number of bytes neccesary for Win95 names
 */
size_t
winLenFixup(un, unlen)
	const u_char* un;
	size_t unlen;
{
	for (un += unlen; unlen > 0; unlen--)
		if (*--un != ' ' && *un != '.')
			break;
	return unlen;
}

/*
 * Store an area with multi byte string instr, and reterns left
 * byte of instr and moves pointer forward. The area's size is
 * inlen or outlen.
 */
static int
mbsadjpos(const char **instr, size_t inlen, size_t outlen, int weight, int flag, void *handle)
{
	char *outp, outstr[outlen * weight + 1];

	if (flag & MSDOSFSMNT_KICONV && msdosfs_iconv) {
		outp = outstr;
		outlen *= weight;
		msdosfs_iconv->conv(handle, instr, &inlen, &outp, &outlen);
		return (inlen);
	}

	(*instr) += min(inlen, outlen);
	return (inlen - min(inlen, outlen));
}

/*
 * Convert DOS char to Local char
 */
static u_char *
dos2unixchr(u_char *outbuf, const u_char **instr, size_t *ilen, int lower, struct msdosfsmount *pmp)
{
	u_char c, *outp;
	size_t len, olen;

	outp = outbuf;
	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
		olen = len = 4;

		if (lower & (LCASE_BASE | LCASE_EXT))
			msdosfs_iconv->convchr_case(pmp->pm_d2u, (const char **)instr,
						  ilen, (char **)&outp, &olen, KICONV_LOWER);
		else
			msdosfs_iconv->convchr(pmp->pm_d2u, (const char **)instr,
					     ilen, (char **)&outp, &olen);
		len -= olen;

		/*
		 * return '?' if failed to convert
		 */
		if (len == 0) {
			(*ilen)--;
			(*instr)++;
			*outp++ = '?';
		}
	} else {
		(*ilen)--;
		c = *(*instr)++;
		c = dos2unix[c];
		if (lower & (LCASE_BASE | LCASE_EXT))
			c = u2l[c];
		*outp++ = c;
		outbuf[1] = '\0';
	}

	*outp = '\0';
	outp = outbuf;
	return (outp);
}

/*
 * Convert Local char to DOS char
 */
static u_int16_t
unix2doschr(const u_char **instr, size_t *ilen, struct msdosfsmount *pmp)
{
	u_char c;
	char *up, *outp, unicode[3], outbuf[3];
	u_int16_t wc;
	size_t len, ucslen, unixlen, olen;

	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
		/*
		 * to hide an invisible character, using a unicode filter
		 */
		ucslen = 2;
		len = *ilen;
		up = unicode;
		msdosfs_iconv->convchr(pmp->pm_u2w, (const char **)instr,
				     ilen, &up, &ucslen);
		unixlen = len - *ilen;

		/*
		 * cannot be converted
		 */
		if (unixlen == 0) {
			(*ilen)--;
			(*instr)++;
			return (0);
		}

		/*
		 * return magic number for ascii char
		 */
		if (unixlen == 1) {
			c = *(*instr -1);
			if (! (c & 0x80)) {
				c = unix2dos[c];
				if (c <= 2)
					return (c);
			}
		}

		/*
		 * now convert using libiconv
		 */
		*instr -= unixlen;
		*ilen = len;

		olen = len = 2;
		outp = outbuf;
		msdosfs_iconv->convchr_case(pmp->pm_u2d, (const char **)instr,
					  ilen, &outp, &olen, KICONV_FROM_UPPER);
		len -= olen;

		/*
		 * cannot be converted, but has unicode char, should return magic number
		 */
		if (len == 0) {
			(*ilen) -= unixlen;
			(*instr) += unixlen;
			return (1);
		}

		wc = 0;
		while(len--)
			wc |= (*(outp - len - 1) & 0xff) << (len << 3);
		return (wc);
	}

	(*ilen)--;
	c = *(*instr)++;
	c = l2u[c];
	c = unix2dos[c];
	return ((u_int16_t)c);
}

/*
 * Convert Windows char to Local char
 */
static u_char *
win2unixchr(u_char *outbuf, u_int16_t wc, struct msdosfsmount *pmp)
{
	u_char *inp, *outp, inbuf[3];
	size_t ilen, olen, len;

	outp = outbuf;
	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
		inbuf[0] = (u_char)(wc>>8);
		inbuf[1] = (u_char)wc;
		inbuf[2] = '\0';

		ilen = 2;
		olen = len = 4;
		inp = inbuf;
		msdosfs_iconv->convchr(pmp->pm_w2u, (const char **)&inp, &ilen,
				     (char **)&outp, &olen);
		len -= olen;

		/*
		 * return '?' if failed to convert
		 */
		if (len == 0)
			*outp++ = '?';
	} else {
		*outp++ = (wc & 0xff00) ? '?' : (u_char)(wc & 0xff);
	}

	*outp = '\0';
	outp = outbuf;
	return (outp);
}

/*
 * Convert Local char to Windows char
 */
static u_int16_t
unix2winchr(const u_char **instr, size_t *ilen, int lower, struct msdosfsmount *pmp)
{
	u_char *outp, outbuf[3];
	u_int16_t wc;
	size_t olen;

	if (*ilen == 0)
		return (0);

	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
		outp = outbuf;
		olen = 2;
		if (lower & (LCASE_BASE | LCASE_EXT))
			msdosfs_iconv->convchr_case(pmp->pm_u2w, (const char **)instr,
						  ilen, (char **)&outp, &olen,
						  KICONV_FROM_LOWER);
		else
			msdosfs_iconv->convchr(pmp->pm_u2w, (const char **)instr,
					     ilen, (char **)&outp, &olen);

		/*
		 * return '0' if end of filename
		 */
		if (olen == 2)
			return (0);

		wc = (outbuf[0]<<8) | outbuf[1];

		return (wc);
	}

	(*ilen)--;
	wc = (*instr)[0];
	if (lower & (LCASE_BASE | LCASE_EXT))
		wc = u2l[wc];
	(*instr)++;
	return (wc);
}

/*
 * Initialize the temporary concatenation buffer.
 */
void
mbnambuf_init(struct mbnambuf *nbp)
{

	nbp->nb_len = 0;
	nbp->nb_last_id = -1;
	nbp->nb_buf[sizeof(nbp->nb_buf) - 1] = '\0';
}

/*
 * Fill out our concatenation buffer with the given substring, at the offset
 * specified by its id.  Since this function must be called with ids in
 * descending order, we take advantage of the fact that ASCII substrings are
 * exactly WIN_CHARS in length.  For non-ASCII substrings, we shift all
 * previous (i.e. higher id) substrings upwards to make room for this one.
 * This only penalizes portions of substrings that contain more than
 * WIN_CHARS bytes when they are first encountered.
 */
void
mbnambuf_write(struct mbnambuf *nbp, char *name, int id)
{
	char *slot;
	size_t count, newlen;

	if (nbp->nb_len != 0 && id != nbp->nb_last_id - 1) {
#ifdef MSDOSFS_DEBUG
		printf("msdosfs: non-decreasing id: id %d, last id %d\n",
		    id, nbp->nb_last_id);
#endif
		return;
	}

	/* Will store this substring in a WIN_CHARS-aligned slot. */
	slot = &nbp->nb_buf[id * WIN_CHARS];
	count = strlen(name);
	newlen = nbp->nb_len + count;
	if (newlen > WIN_MAXLEN || newlen > MAXNAMLEN) {
#ifdef MSDOSFS_DEBUG
		printf("msdosfs: file name length %zu too large\n", newlen);
#endif
		return;
	}

	/* Shift suffix upwards by the amount length exceeds WIN_CHARS. */
	if (count > WIN_CHARS && nbp->nb_len != 0)
		bcopy(slot + WIN_CHARS, slot + count, nbp->nb_len);

	/* Copy in the substring to its slot and update length so far. */
	bcopy(name, slot, count);
	nbp->nb_len = newlen;
	nbp->nb_last_id = id;
}

/*
 * Take the completed string and use it to setup the struct dirent.
 * Be sure to always nul-terminate the d_name and then copy the string
 * from our buffer.  Note that this function assumes the full string has
 * been reassembled in the buffer.  If it's called before all substrings
 * have been written via mbnambuf_write(), the result will be incorrect.
 */
char *
mbnambuf_flush(struct mbnambuf *nbp, struct dirent *dp)
{

	if (nbp->nb_len > sizeof(dp->d_name) - 1) {
		mbnambuf_init(nbp);
		return (NULL);
	}
	bcopy(&nbp->nb_buf[0], dp->d_name, nbp->nb_len);
	dp->d_name[nbp->nb_len] = '\0';
	dp->d_namlen = nbp->nb_len;

	mbnambuf_init(nbp);
	return (dp->d_name);
}
