fs/nls/nls_base.c

   1 /*
   2  * linux/fs/nls/nls_base.c
   3  *
   4  * Native language support--charsets and unicode translations.
   5  * By Gordon Chaffee 1996, 1997
   6  *
   7  * Unicode based case conversion 1999 by Wolfram Pienkoss
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/string.h>
  13 #include <linux/nls.h>
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/kmod.h>
  17 #include <linux/spinlock.h>
  18 #include <asm/byteorder.h>
  19
  20 static struct nls_table default_table;
  21 static struct nls_table *tables = &default_table;
  22 static DEFINE_SPINLOCK(nls_lock);
  23
  24 /*
  25  * Sample implementation from Unicode home page.
  26  * http://www.stonehand.com/unicode/standard/fss-utf.html
  27  */
  28 struct utf8_table {
  29         int     cmask;
  30         int     cval;
  31         int     shift;
  32         long    lmask;
  33         long    lval;
  34 };
  35
  36 static const struct utf8_table utf8_table[] =
  37 {
  38     {0x80,  0x00,   0*6,    0x7F,           0,         /* 1 byte sequence */},
  39     {0xE0,  0xC0,   1*6,    0x7FF,          0x80,      /* 2 byte sequence */},
  40     {0xF0,  0xE0,   2*6,    0xFFFF,         0x800,     /* 3 byte sequence */},
  41     {0xF8,  0xF0,   3*6,    0x1FFFFF,       0x10000,   /* 4 byte sequence */},
  42     {0xFC,  0xF8,   4*6,    0x3FFFFFF,      0x200000,  /* 5 byte sequence */},
  43     {0xFE,  0xFC,   5*6,    0x7FFFFFFF,     0x4000000, /* 6 byte sequence */},
  44     {0,                                                /* end of table    */}
  45 };
  46
  47 #define UNICODE_MAX     0x0010ffff
  48 #define PLANE_SIZE      0x00010000
  49
  50 #define SURROGATE_MASK  0xfffff800
  51 #define SURROGATE_PAIR  0x0000d800
  52 #define SURROGATE_LOW   0x00000400
  53 #define SURROGATE_BITS  0x000003ff
  54
  55 int utf8_to_utf32(const u8 *s, int inlen, unicode_t *pu)
  56 {
  57         unsigned long l;
  58         int c0, c, nc;
  59         const struct utf8_table *t;
  60
  61         nc = 0;
  62         c0 = *s;
  63         l = c0;
  64         for (t = utf8_table; t->cmask; t++) {
  65                 nc++;
  66                 if ((c0 & t->cmask) == t->cval) {
  67                         l &= t->lmask;
  68                         if (l < t->lval || l > UNICODE_MAX ||
  69                                         (l & SURROGATE_MASK) == SURROGATE_PAIR)
  70                                 return -1;
  71                         *pu = (unicode_t) l;
  72                         return nc;
  73                 }
  74                 if (inlen <= nc)
  75                         return -1;
  76                 s++;
  77                 c = (*s ^ 0x80) & 0xFF;
  78                 if (c & 0xC0)
  79                         return -1;
  80                 l = (l << 6) | c;
  81         }
  82         return -1;
  83 }
  84 EXPORT_SYMBOL(utf8_to_utf32);
  85
  86 int utf32_to_utf8(unicode_t u, u8 *s, int maxout)
  87 {
  88         unsigned long l;
  89         int c, nc;
  90         const struct utf8_table *t;
  91
  92         if (!s)
  93                 return 0;
  94
  95         l = u;
  96         if (l > UNICODE_MAX || (l & SURROGATE_MASK) == SURROGATE_PAIR)
  97                 return -1;
  98
  99         nc = 0;
 100         for (t = utf8_table; t->cmask && maxout; t++, maxout--) {
 101                 nc++;
 102                 if (l <= t->lmask) {
 103                         c = t->shift;
 104                         *s = (u8) (t->cval | (l >> c));
 105                         while (c > 0) {
 106                                 c -= 6;
 107                                 s++;
 108                                 *s = (u8) (0x80 | ((l >> c) & 0x3F));
 109                         }
 110                         return nc;
 111                 }
 112         }
 113         return -1;
 114 }
 115 EXPORT_SYMBOL(utf32_to_utf8);
 116
 117 static inline void put_utf16(wchar_t *s, unsigned c, enum utf16_endian endian)
 118 {
 119         switch (endian) {
 120         default:
 121                 *s = (wchar_t) c;
 122                 break;
 123         case UTF16_LITTLE_ENDIAN:
 124                 *s = __cpu_to_le16(c);
 125                 break;
 126         case UTF16_BIG_ENDIAN:
 127                 *s = __cpu_to_be16(c);
 128                 break;
 129         }
 130 }
 131
 132 int utf8s_to_utf16s(const u8 *s, int inlen, enum utf16_endian endian,
 133                 wchar_t *pwcs, int maxout)
 134 {
 135         u16 *op;
 136         int size;
 137         unicode_t u;
 138
 139         op = pwcs;
 140         while (inlen > 0 && maxout > 0 && *s) {
 141                 if (*s & 0x80) {
 142                         size = utf8_to_utf32(s, inlen, &u);
 143                         if (size < 0)
 144                                 return -EINVAL;
 145                         s += size;
 146                         inlen -= size;
 147
 148                         if (u >= PLANE_SIZE) {
 149                                 if (maxout < 2)
 150                                         break;
 151                                 u -= PLANE_SIZE;
 152                                 put_utf16(op++, SURROGATE_PAIR |
 153                                                 ((u >> 10) & SURROGATE_BITS),
 154                                                 endian);
 155                                 put_utf16(op++, SURROGATE_PAIR |
 156                                                 SURROGATE_LOW |
 157                                                 (u & SURROGATE_BITS),
 158                                                 endian);
 159                                 maxout -= 2;
 160                         } else {
 161                                 put_utf16(op++, u, endian);
 162                                 maxout--;
 163                         }
 164                 } else {
 165                         put_utf16(op++, *s++, endian);
 166                         inlen--;
 167                         maxout--;
 168                 }
 169         }
 170         return op - pwcs;
 171 }
 172 EXPORT_SYMBOL(utf8s_to_utf16s);
 173
 174 static inline unsigned long get_utf16(unsigned c, enum utf16_endian endian)
 175 {
 176         switch (endian) {
 177         default:
 178                 return c;
 179         case UTF16_LITTLE_ENDIAN:
 180                 return __le16_to_cpu(c);
 181         case UTF16_BIG_ENDIAN:
 182                 return __be16_to_cpu(c);
 183         }
 184 }
 185
 186 int utf16s_to_utf8s(const wchar_t *pwcs, int inlen, enum utf16_endian endian,
 187                 u8 *s, int maxout)
 188 {
 189         u8 *op;
 190         int size;
 191         unsigned long u, v;
 192
 193         op = s;
 194         while (inlen > 0 && maxout > 0) {
 195                 u = get_utf16(*pwcs, endian);
 196                 if (!u)
 197                         break;
 198                 pwcs++;
 199                 inlen--;
 200                 if (u > 0x7f) {
 201                         if ((u & SURROGATE_MASK) == SURROGATE_PAIR) {
 202                                 if (u & SURROGATE_LOW) {
 203                                         /* Ignore character and move on */
 204                                         continue;
 205                                 }
 206                                 if (inlen <= 0)
 207                                         break;
 208                                 v = get_utf16(*pwcs, endian);
 209                                 if ((v & SURROGATE_MASK) != SURROGATE_PAIR ||
 210                                                 !(v & SURROGATE_LOW)) {
 211                                         /* Ignore character and move on */
 212                                         continue;
 213                                 }
 214                                 u = PLANE_SIZE + ((u & SURROGATE_BITS) << 10)
 215                                                 + (v & SURROGATE_BITS);
 216                                 pwcs++;
 217                                 inlen--;
 218                         }
 219                         size = utf32_to_utf8(u, op, maxout);
 220                         if (size == -1) {
 221                                 /* Ignore character and move on */
 222                         } else {
 223                                 op += size;
 224                                 maxout -= size;
 225                         }
 226                 } else {
 227                         *op++ = (u8) u;
 228                         maxout--;
 229                 }
 230         }
 231         return op - s;
 232 }
 233 EXPORT_SYMBOL(utf16s_to_utf8s);
 234
 235 int __register_nls(struct nls_table *nls, struct module *owner)
 236 {
 237         struct nls_table ** tmp = &tables;
 238
 239         if (nls->next)
 240                 return -EBUSY;
 241
 242         nls->owner = owner;
 243         spin_lock(&nls_lock);
 244         while (*tmp) {
 245                 if (nls == *tmp) {
 246                         spin_unlock(&nls_lock);
 247                         return -EBUSY;
 248                 }
 249                 tmp = &(*tmp)->next;
 250         }
 251         nls->next = tables;
 252         tables = nls;
 253         spin_unlock(&nls_lock);
 254         return 0;
 255 }
 256 EXPORT_SYMBOL(__register_nls);
 257
 258 int unregister_nls(struct nls_table * nls)
 259 {
 260         struct nls_table ** tmp = &tables;
 261
 262         spin_lock(&nls_lock);
 263         while (*tmp) {
 264                 if (nls == *tmp) {
 265                         *tmp = nls->next;
 266                         spin_unlock(&nls_lock);
 267                         return 0;
 268                 }
 269                 tmp = &(*tmp)->next;
 270         }
 271         spin_unlock(&nls_lock);
 272         return -EINVAL;
 273 }
 274
 275 static struct nls_table *find_nls(const char *charset)
 276 {
 277         struct nls_table *nls;
 278         spin_lock(&nls_lock);
 279         for (nls = tables; nls; nls = nls->next) {
 280                 if (!strcmp(nls->charset, charset))
 281                         break;
 282                 if (nls->alias && !strcmp(nls->alias, charset))
 283                         break;
 284         }
 285         if (nls && !try_module_get(nls->owner))
 286                 nls = NULL;
 287         spin_unlock(&nls_lock);
 288         return nls;
 289 }
 290
 291 struct nls_table *load_nls(const char *charset)
 292 {
 293         return try_then_request_module(find_nls(charset), "nls_%s", charset);
 294 }
 295
 296 void unload_nls(struct nls_table *nls)
 297 {
 298         if (nls)
 299                 module_put(nls->owner);
 300 }
 301
 302 static const wchar_t charset2uni[256] = {
 303         /* 0x00*/
 304         0x0000, 0x0001, 0x0002, 0x0003,
 305         0x0004, 0x0005, 0x0006, 0x0007,
 306         0x0008, 0x0009, 0x000a, 0x000b,
 307         0x000c, 0x000d, 0x000e, 0x000f,
 308         /* 0x10*/
 309         0x0010, 0x0011, 0x0012, 0x0013,
 310         0x0014, 0x0015, 0x0016, 0x0017,
 311         0x0018, 0x0019, 0x001a, 0x001b,
 312         0x001c, 0x001d, 0x001e, 0x001f,
 313         /* 0x20*/
 314         0x0020, 0x0021, 0x0022, 0x0023,
 315         0x0024, 0x0025, 0x0026, 0x0027,
 316         0x0028, 0x0029, 0x002a, 0x002b,
 317         0x002c, 0x002d, 0x002e, 0x002f,
 318         /* 0x30*/
 319         0x0030, 0x0031, 0x0032, 0x0033,
 320         0x0034, 0x0035, 0x0036, 0x0037,
 321         0x0038, 0x0039, 0x003a, 0x003b,
 322         0x003c, 0x003d, 0x003e, 0x003f,
 323         /* 0x40*/
 324         0x0040, 0x0041, 0x0042, 0x0043,
 325         0x0044, 0x0045, 0x0046, 0x0047,
 326         0x0048, 0x0049, 0x004a, 0x004b,
 327         0x004c, 0x004d, 0x004e, 0x004f,
 328         /* 0x50*/
 329         0x0050, 0x0051, 0x0052, 0x0053,
 330         0x0054, 0x0055, 0x0056, 0x0057,
 331         0x0058, 0x0059, 0x005a, 0x005b,
 332         0x005c, 0x005d, 0x005e, 0x005f,
 333         /* 0x60*/
 334         0x0060, 0x0061, 0x0062, 0x0063,
 335         0x0064, 0x0065, 0x0066, 0x0067,
 336         0x0068, 0x0069, 0x006a, 0x006b,
 337         0x006c, 0x006d, 0x006e, 0x006f,
 338         /* 0x70*/
 339         0x0070, 0x0071, 0x0072, 0x0073,
 340         0x0074, 0x0075, 0x0076, 0x0077,
 341         0x0078, 0x0079, 0x007a, 0x007b,
 342         0x007c, 0x007d, 0x007e, 0x007f,
 343         /* 0x80*/
 344         0x0080, 0x0081, 0x0082, 0x0083,
 345         0x0084, 0x0085, 0x0086, 0x0087,
 346         0x0088, 0x0089, 0x008a, 0x008b,
 347         0x008c, 0x008d, 0x008e, 0x008f,
 348         /* 0x90*/
 349         0x0090, 0x0091, 0x0092, 0x0093,
 350         0x0094, 0x0095, 0x0096, 0x0097,
 351         0x0098, 0x0099, 0x009a, 0x009b,
 352         0x009c, 0x009d, 0x009e, 0x009f,
 353         /* 0xa0*/
 354         0x00a0, 0x00a1, 0x00a2, 0x00a3,
 355         0x00a4, 0x00a5, 0x00a6, 0x00a7,
 356         0x00a8, 0x00a9, 0x00aa, 0x00ab,
 357         0x00ac, 0x00ad, 0x00ae, 0x00af,
 358         /* 0xb0*/
 359         0x00b0, 0x00b1, 0x00b2, 0x00b3,
 360         0x00b4, 0x00b5, 0x00b6, 0x00b7,
 361         0x00b8, 0x00b9, 0x00ba, 0x00bb,
 362         0x00bc, 0x00bd, 0x00be, 0x00bf,
 363         /* 0xc0*/
 364         0x00c0, 0x00c1, 0x00c2, 0x00c3,
 365         0x00c4, 0x00c5, 0x00c6, 0x00c7,
 366         0x00c8, 0x00c9, 0x00ca, 0x00cb,
 367         0x00cc, 0x00cd, 0x00ce, 0x00cf,
 368         /* 0xd0*/
 369         0x00d0, 0x00d1, 0x00d2, 0x00d3,
 370         0x00d4, 0x00d5, 0x00d6, 0x00d7,
 371         0x00d8, 0x00d9, 0x00da, 0x00db,
 372         0x00dc, 0x00dd, 0x00de, 0x00df,
 373         /* 0xe0*/
 374         0x00e0, 0x00e1, 0x00e2, 0x00e3,
 375         0x00e4, 0x00e5, 0x00e6, 0x00e7,
 376         0x00e8, 0x00e9, 0x00ea, 0x00eb,
 377         0x00ec, 0x00ed, 0x00ee, 0x00ef,
 378         /* 0xf0*/
 379         0x00f0, 0x00f1, 0x00f2, 0x00f3,
 380         0x00f4, 0x00f5, 0x00f6, 0x00f7,
 381         0x00f8, 0x00f9, 0x00fa, 0x00fb,
 382         0x00fc, 0x00fd, 0x00fe, 0x00ff,
 383 };
 384
 385 static const unsigned char page00[256] = {
 386         0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 387         0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 388         0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
 389         0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 0x18-0x1f */
 390         0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 0x20-0x27 */
 391         0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 0x28-0x2f */
 392         0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 0x30-0x37 */
 393         0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 0x38-0x3f */
 394         0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, /* 0x40-0x47 */
 395         0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, /* 0x48-0x4f */
 396         0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, /* 0x50-0x57 */
 397         0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 0x58-0x5f */
 398         0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 0x60-0x67 */
 399         0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 0x68-0x6f */
 400         0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 0x70-0x77 */
 401         0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
 402
 403         0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 0x80-0x87 */
 404         0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 0x88-0x8f */
 405         0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 0x90-0x97 */
 406         0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 0x98-0x9f */
 407         0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* 0xa0-0xa7 */
 408         0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* 0xa8-0xaf */
 409         0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* 0xb0-0xb7 */
 410         0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* 0xb8-0xbf */
 411         0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, /* 0xc0-0xc7 */
 412         0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, /* 0xc8-0xcf */
 413         0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, /* 0xd0-0xd7 */
 414         0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, /* 0xd8-0xdf */
 415         0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* 0xe0-0xe7 */
 416         0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* 0xe8-0xef */
 417         0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* 0xf0-0xf7 */
 418         0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
 419 };
 420
 421 static const unsigned char *const page_uni2charset[256] = {
 422         page00
 423 };
 424
 425 static const unsigned char charset2lower[256] = {
 426         0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 427         0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 428         0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
 429         0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 0x18-0x1f */
 430         0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 0x20-0x27 */
 431         0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 0x28-0x2f */
 432         0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 0x30-0x37 */
 433         0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 0x38-0x3f */
 434         0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 0x40-0x47 */
 435         0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 0x48-0x4f */
 436         0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 0x50-0x57 */
 437         0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 0x58-0x5f */
 438         0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 0x60-0x67 */
 439         0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 0x68-0x6f */
 440         0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 0x70-0x77 */
 441         0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
 442
 443         0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 0x80-0x87 */
 444         0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 0x88-0x8f */
 445         0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 0x90-0x97 */
 446         0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 0x98-0x9f */
 447         0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* 0xa0-0xa7 */
 448         0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* 0xa8-0xaf */
 449         0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* 0xb0-0xb7 */
 450         0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* 0xb8-0xbf */
 451         0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, /* 0xc0-0xc7 */
 452         0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, /* 0xc8-0xcf */
 453         0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, /* 0xd0-0xd7 */
 454         0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, /* 0xd8-0xdf */
 455         0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* 0xe0-0xe7 */
 456         0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* 0xe8-0xef */
 457         0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* 0xf0-0xf7 */
 458         0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
 459 };
 460
 461 static const unsigned char charset2upper[256] = {
 462         0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 463         0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 464         0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
 465         0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 0x18-0x1f */
 466         0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 0x20-0x27 */
 467         0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 0x28-0x2f */
 468         0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 0x30-0x37 */
 469         0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 0x38-0x3f */
 470         0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, /* 0x40-0x47 */
 471         0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, /* 0x48-0x4f */
 472         0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, /* 0x50-0x57 */
 473         0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 0x58-0x5f */
 474         0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, /* 0x60-0x67 */
 475         0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, /* 0x68-0x6f */
 476         0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, /* 0x70-0x77 */
 477         0x58, 0x59, 0x5a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
 478
 479         0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 0x80-0x87 */
 480         0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 0x88-0x8f */
 481         0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 0x90-0x97 */
 482         0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 0x98-0x9f */
 483         0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* 0xa0-0xa7 */
 484         0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* 0xa8-0xaf */
 485         0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* 0xb0-0xb7 */
 486         0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* 0xb8-0xbf */
 487         0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, /* 0xc0-0xc7 */
 488         0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, /* 0xc8-0xcf */
 489         0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, /* 0xd0-0xd7 */
 490         0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, /* 0xd8-0xdf */
 491         0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* 0xe0-0xe7 */
 492         0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* 0xe8-0xef */
 493         0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* 0xf0-0xf7 */
 494         0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
 495 };
 496
 497
 498 static int uni2char(wchar_t uni, unsigned char *out, int boundlen)
 499 {
 500         const unsigned char *uni2charset;
 501         unsigned char cl = uni & 0x00ff;
 502         unsigned char ch = (uni & 0xff00) >> 8;
 503
 504         if (boundlen <= 0)
 505                 return -ENAMETOOLONG;
 506
 507         uni2charset = page_uni2charset[ch];
 508         if (uni2charset && uni2charset[cl])
 509                 out[0] = uni2charset[cl];
 510         else
 511                 return -EINVAL;
 512         return 1;
 513 }
 514
 515 static int char2uni(const unsigned char *rawstring, int boundlen, wchar_t *uni)
 516 {
 517         *uni = charset2uni[*rawstring];
 518         if (*uni == 0x0000)
 519                 return -EINVAL;
 520         return 1;
 521 }
 522
 523 static struct nls_table default_table = {
 524         .charset        = "default",
 525         .uni2char       = uni2char,
 526         .char2uni       = char2uni,
 527         .charset2lower  = charset2lower,
 528         .charset2upper  = charset2upper,
 529 };
 530
 531 /* Returns a simple default translation table */
 532 struct nls_table *load_nls_default(void)
 533 {
 534         struct nls_table *default_nls;
 535
 536         default_nls = load_nls(CONFIG_NLS_DEFAULT);
 537         if (default_nls != NULL)
 538                 return default_nls;
 539         else
 540                 return &default_table;
 541 }
 542
 543 EXPORT_SYMBOL(unregister_nls);
 544 EXPORT_SYMBOL(unload_nls);
 545 EXPORT_SYMBOL(load_nls);
 546 EXPORT_SYMBOL(load_nls_default);
 547
 548 MODULE_LICENSE("Dual BSD/GPL");