linux-imx

/*

 * unicode.c

 *

 * PURPOSE

 *  Routines for converting between UTF-8 and OSTA Compressed Unicode.

 *      Also handles filename mangling

 *

 * DESCRIPTION

 *  OSTA Compressed Unicode is explained in the OSTA UDF specification.

 *      http://www.osta.org/

 *  UTF-8 is explained in the IETF RFC XXXX.

 *      ftp://ftp.internic.net/rfc/rfcxxxx.txt

 *

 * COPYRIGHT

 *  This file is distributed under the terms of the GNU General Public

 *  License (GPL). Copies of the GPL can be obtained from:

 *      ftp://prep.ai.mit.edu/pub/gnu/GPL

 *  Each contributing author retains all rights to their own work.

 */

​

#include "udfdecl.h"

​

#include <linux/kernel.h>

#include <linux/string.h>   /* for memset */

#include <linux/nls.h>

#include <linux/crc-itu-t.h>

#include <linux/slab.h>

​

#include "udf_sb.h"

​

#define PLANE_SIZE 0x10000

#define UNICODE_MAX 0x10ffff

#define SURROGATE_MASK 0xfffff800

#define SURROGATE_PAIR 0x0000d800

#define SURROGATE_LOW  0x00000400

#define SURROGATE_CHAR_BITS 10

#define SURROGATE_CHAR_MASK ((1 << SURROGATE_CHAR_BITS) - 1)

​

#define ILLEGAL_CHAR_MARK   '_'

#define EXT_MARK        '.'

#define CRC_MARK        '#'

#define EXT_SIZE        5

/* Number of chars we need to store generated CRC to make filename unique */

#define CRC_LEN         5

​

static unicode_t get_utf16_char(const uint8_t *str_i, int str_i_max_len,

                int str_i_idx, int u_ch, unicode_t *ret)

{

    unicode_t c;

    int start_idx = str_i_idx;

​

    /* Expand OSTA compressed Unicode to Unicode */

    c = str_i[str_i_idx++];

    if (u_ch > 1)

        c = (c << 8) | str_i[str_i_idx++];

    if ((c & SURROGATE_MASK) == SURROGATE_PAIR) {

        unicode_t next;

​

        /* Trailing surrogate char */

        if (str_i_idx >= str_i_max_len) {

            c = UNICODE_MAX + 1;

            goto out;

        }

​

        /* Low surrogate must follow the high one... */

        if (c & SURROGATE_LOW) {

            c = UNICODE_MAX + 1;

            goto out;

        }

​

        WARN_ON_ONCE(u_ch != 2);

        next = str_i[str_i_idx++] << 8;

        next |= str_i[str_i_idx++];

        if ((next & SURROGATE_MASK) != SURROGATE_PAIR ||

            !(next & SURROGATE_LOW)) {

            c = UNICODE_MAX + 1;

            goto out;

        }

​

        c = PLANE_SIZE +

            ((c & SURROGATE_CHAR_MASK) << SURROGATE_CHAR_BITS) +

            (next & SURROGATE_CHAR_MASK);

    }

out:

    *ret = c;

    return str_i_idx - start_idx;

}

​

​

static int udf_name_conv_char(uint8_t *str_o, int str_o_max_len,

                  int *str_o_idx,

                  const uint8_t *str_i, int str_i_max_len,