// 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)
{
        struct nls_table *nls;
        unsigned char len = 0;

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

        if (!nls) {
                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;
}