// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/isofs/joliet.c
 *
 *  (C) 1996 Gordon Chaffee
 *
 *  Joliet: Microsoft's Unicode extensions to iso9660
 */

#include <linux/types.h>
#include <linux/nls.h>
#include "isofs.h"

/*
 * Convert Unicode 16 to UTF-8 or ASCII.
 */
static int
uni16_to_x8(unsigned char *ascii, __be16 *uni, int len, struct nls_table *nls)
{
	__be16 *ip, ch;
	unsigned char *op;

	ip = uni;
	op = ascii;

	while ((ch = get_unaligned(ip)) && len) {
		int llen;
		llen = nls->uni2char(be16_to_cpu(ch), op, NLS_MAX_CHARSET_SIZE);
		if (llen > 0)
			op += llen;
		else
			*op++ = '?';
		ip++;

		len--;
	}
	*op = 0;
	return (op - ascii);
}

int
get_joliet_filename(struct iso_directory_record * de, unsigned char *outname, struct inode * inode)
{
	unsigned char utf8;
	struct nls_table *nls;
	unsigned char len = 0;

	utf8 = ISOFS_SB(inode->i_sb)->s_utf8;
	nls = ISOFS_SB(inode->i_sb)->s_nls_iocharset;

	if (utf8) {
		len = utf16s_to_utf8s((const wchar_t *) de->name,
				de->name_len[0] >> 1, UTF16_BIG_ENDIAN,
				outname, PAGE_SIZE);
	} else {
		len = uni16_to_x8(outname, (__be16 *) de->name,
				de->name_len[0] >> 1, nls);
	}
	if ((len > 2) && (outname[len-2] == ';') && (outname[len-1] == '1'))
		len -= 2;

	/*
	 * Windows doesn't like periods at the end of a name,
	 * so neither do we
	 */
	while (len >= 2 && (outname[len-1] == '.'))
		len--;

	return len;
}