fs/hfsplus/unicode.c

   1 /*
   2  *  linux/fs/hfsplus/unicode.c
   3  *
   4  * Copyright (C) 2001
   5  * Brad Boyer (flar@allandria.com)
   6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7  *
   8  * Handler routines for unicode strings
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/nls.h>
  13 #include "hfsplus_fs.h"
  14 #include "hfsplus_raw.h"
  15
  16 /* Fold the case of a unicode char, given the 16 bit value */
  17 /* Returns folded char, or 0 if ignorable */
  18 static inline u16 case_fold(u16 c)
  19 {
  20         u16 tmp;
  21
  22         tmp = hfsplus_case_fold_table[c >> 8];
  23         if (tmp)
  24                 tmp = hfsplus_case_fold_table[tmp + (c & 0xff)];
  25         else
  26                 tmp = c;
  27         return tmp;
  28 }
  29
  30 /* Compare unicode strings, return values like normal strcmp */
  31 int hfsplus_strcasecmp(const struct hfsplus_unistr *s1,
  32                        const struct hfsplus_unistr *s2)
  33 {
  34         u16 len1, len2, c1, c2;
  35         const hfsplus_unichr *p1, *p2;
  36
  37         len1 = be16_to_cpu(s1->length);
  38         len2 = be16_to_cpu(s2->length);
  39         p1 = s1->unicode;
  40         p2 = s2->unicode;
  41
  42         while (1) {
  43                 c1 = c2 = 0;
  44
  45                 while (len1 && !c1) {
  46                         c1 = case_fold(be16_to_cpu(*p1));
  47                         p1++;
  48                         len1--;
  49                 }
  50                 while (len2 && !c2) {
  51                         c2 = case_fold(be16_to_cpu(*p2));
  52                         p2++;
  53                         len2--;
  54                 }
  55
  56                 if (c1 != c2)
  57                         return (c1 < c2) ? -1 : 1;
  58                 if (!c1 && !c2)
  59                         return 0;
  60         }
  61 }
  62
  63 /* Compare names as a sequence of 16-bit unsigned integers */
  64 int hfsplus_strcmp(const struct hfsplus_unistr *s1,
  65                    const struct hfsplus_unistr *s2)
  66 {
  67         u16 len1, len2, c1, c2;
  68         const hfsplus_unichr *p1, *p2;
  69         int len;
  70
  71         len1 = be16_to_cpu(s1->length);
  72         len2 = be16_to_cpu(s2->length);
  73         p1 = s1->unicode;
  74         p2 = s2->unicode;
  75
  76         for (len = min(len1, len2); len > 0; len--) {
  77                 c1 = be16_to_cpu(*p1);
  78                 c2 = be16_to_cpu(*p2);
  79                 if (c1 != c2)
  80                         return c1 < c2 ? -1 : 1;
  81                 p1++;
  82                 p2++;
  83         }
  84
  85         return len1 < len2 ? -1 :
  86                len1 > len2 ? 1 : 0;
  87 }
  88
  89
  90 #define Hangul_SBase    0xac00
  91 #define Hangul_LBase    0x1100
  92 #define Hangul_VBase    0x1161
  93 #define Hangul_TBase    0x11a7
  94 #define Hangul_SCount   11172
  95 #define Hangul_LCount   19
  96 #define Hangul_VCount   21
  97 #define Hangul_TCount   28
  98 #define Hangul_NCount   (Hangul_VCount * Hangul_TCount)
  99
 100
 101 static u16 *hfsplus_compose_lookup(u16 *p, u16 cc)
 102 {
 103         int i, s, e;
 104
 105         s = 1;
 106         e = p[1];
 107         if (!e || cc < p[s * 2] || cc > p[e * 2])
 108                 return NULL;
 109         do {
 110                 i = (s + e) / 2;
 111                 if (cc > p[i * 2])
 112                         s = i + 1;
 113                 else if (cc < p[i * 2])
 114                         e = i - 1;
 115                 else
 116                         return hfsplus_compose_table + p[i * 2 + 1];
 117         } while (s <= e);
 118         return NULL;
 119 }
 120
 121 int hfsplus_uni2asc(struct super_block *sb, const struct hfsplus_unistr *ustr, char *astr, int *len_p)
 122 {
 123         const hfsplus_unichr *ip;
 124         struct nls_table *nls = HFSPLUS_SB(sb).nls;
 125         u8 *op;
 126         u16 cc, c0, c1;
 127         u16 *ce1, *ce2;
 128         int i, len, ustrlen, res, compose;
 129
 130         op = astr;
 131         ip = ustr->unicode;
 132         ustrlen = be16_to_cpu(ustr->length);
 133         len = *len_p;
 134         ce1 = NULL;
 135         compose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
 136
 137         while (ustrlen > 0) {
 138                 c0 = be16_to_cpu(*ip++);
 139                 ustrlen--;
 140                 /* search for single decomposed char */
 141                 if (likely(compose))
 142                         ce1 = hfsplus_compose_lookup(hfsplus_compose_table, c0);
 143                 if (ce1 && (cc = ce1[0])) {
 144                         /* start of a possibly decomposed Hangul char */
 145                         if (cc != 0xffff)
 146                                 goto done;
 147                         if (!ustrlen)
 148                                 goto same;
 149                         c1 = be16_to_cpu(*ip) - Hangul_VBase;
 150                         if (c1 < Hangul_VCount) {
 151                                 /* compose the Hangul char */
 152                                 cc = (c0 - Hangul_LBase) * Hangul_VCount;
 153                                 cc = (cc + c1) * Hangul_TCount;
 154                                 cc += Hangul_SBase;
 155                                 ip++;
 156                                 ustrlen--;
 157                                 if (!ustrlen)
 158                                         goto done;
 159                                 c1 = be16_to_cpu(*ip) - Hangul_TBase;
 160                                 if (c1 > 0 && c1 < Hangul_TCount) {
 161                                         cc += c1;
 162                                         ip++;
 163                                         ustrlen--;
 164                                 }
 165                                 goto done;
 166                         }
 167                 }
 168                 while (1) {
 169                         /* main loop for common case of not composed chars */
 170                         if (!ustrlen)
 171                                 goto same;
 172                         c1 = be16_to_cpu(*ip);
 173                         if (likely(compose))
 174                                 ce1 = hfsplus_compose_lookup(hfsplus_compose_table, c1);
 175                         if (ce1)
 176                                 break;
 177                         switch (c0) {
 178                         case 0:
 179                                 c0 = 0x2400;
 180                                 break;
 181                         case '/':
 182                                 c0 = ':';
 183                                 break;
 184                         }
 185                         res = nls->uni2char(c0, op, len);
 186                         if (res < 0) {
 187                                 if (res == -ENAMETOOLONG)
 188                                         goto out;
 189                                 *op = '?';
 190                                 res = 1;
 191                         }
 192                         op += res;
 193                         len -= res;
 194                         c0 = c1;
 195                         ip++;
 196                         ustrlen--;
 197                 }
 198                 ce2 = hfsplus_compose_lookup(ce1, c0);
 199                 if (ce2) {
 200                         i = 1;
 201                         while (i < ustrlen) {
 202                                 ce1 = hfsplus_compose_lookup(ce2, be16_to_cpu(ip[i]));
 203                                 if (!ce1)
 204                                         break;
 205                                 i++;
 206                                 ce2 = ce1;
 207                         }
 208                         if ((cc = ce2[0])) {
 209                                 ip += i;
 210                                 ustrlen -= i;
 211                                 goto done;
 212                         }
 213                 }
 214         same:
 215                 switch (c0) {
 216                 case 0:
 217                         cc = 0x2400;
 218                         break;
 219                 case '/':
 220                         cc = ':';
 221                         break;
 222                 default:
 223                         cc = c0;
 224                 }
 225         done:
 226                 res = nls->uni2char(cc, op, len);
 227                 if (res < 0) {
 228                         if (res == -ENAMETOOLONG)
 229                                 goto out;
 230                         *op = '?';
 231                         res = 1;
 232                 }
 233                 op += res;
 234                 len -= res;
 235         }
 236         res = 0;
 237 out:
 238         *len_p = (char *)op - astr;
 239         return res;
 240 }
 241
 242 /*
 243  * Convert one or more ASCII characters into a single unicode character.
 244  * Returns the number of ASCII characters corresponding to the unicode char.
 245  */
 246 static inline int asc2unichar(struct super_block *sb, const char *astr, int len,
 247                               wchar_t *uc)
 248 {
 249         int size = HFSPLUS_SB(sb).nls->char2uni(astr, len, uc);
 250         if (size <= 0) {
 251                 *uc = '?';
 252                 size = 1;
 253         }
 254         switch (*uc) {
 255         case 0x2400:
 256                 *uc = 0;
 257                 break;
 258         case ':':
 259                 *uc = '/';
 260                 break;
 261         }
 262         return size;
 263 }
 264
 265 /* Decomposes a single unicode character. */
 266 static inline u16 *decompose_unichar(wchar_t uc, int *size)
 267 {
 268         int off;
 269
 270         off = hfsplus_decompose_table[(uc >> 12) & 0xf];
 271         if (off == 0 || off == 0xffff)
 272                 return NULL;
 273
 274         off = hfsplus_decompose_table[off + ((uc >> 8) & 0xf)];
 275         if (!off)
 276                 return NULL;
 277
 278         off = hfsplus_decompose_table[off + ((uc >> 4) & 0xf)];
 279         if (!off)
 280                 return NULL;
 281
 282         off = hfsplus_decompose_table[off + (uc & 0xf)];
 283         *size = off & 3;
 284         if (*size == 0)
 285                 return NULL;
 286         return hfsplus_decompose_table + (off / 4);
 287 }
 288
 289 int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr,
 290                     const char *astr, int len)
 291 {
 292         int size, dsize, decompose;
 293         u16 *dstr, outlen = 0;
 294         wchar_t c;
 295
 296         decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
 297         while (outlen < HFSPLUS_MAX_STRLEN && len > 0) {
 298                 size = asc2unichar(sb, astr, len, &c);
 299
 300                 if (decompose && (dstr = decompose_unichar(c, &dsize))) {
 301                         if (outlen + dsize > HFSPLUS_MAX_STRLEN)
 302                                 break;
 303                         do {
 304                                 ustr->unicode[outlen++] = cpu_to_be16(*dstr++);
 305                         } while (--dsize > 0);
 306                 } else
 307                         ustr->unicode[outlen++] = cpu_to_be16(c);
 308
 309                 astr += size;
 310                 len -= size;
 311         }
 312         ustr->length = cpu_to_be16(outlen);
 313         if (len > 0)
 314                 return -ENAMETOOLONG;
 315         return 0;
 316 }
 317
 318 /*
 319  * Hash a string to an integer as appropriate for the HFS+ filesystem.
 320  * Composed unicode characters are decomposed and case-folding is performed
 321  * if the appropriate bits are (un)set on the superblock.
 322  */
 323 int hfsplus_hash_dentry(struct dentry *dentry, struct qstr *str)
 324 {
 325         struct super_block *sb = dentry->d_sb;
 326         const char *astr;
 327         const u16 *dstr;
 328         int casefold, decompose, size, dsize, len;
 329         unsigned long hash;
 330         wchar_t c;
 331         u16 c2;
 332
 333         casefold = (HFSPLUS_SB(sb).flags & HFSPLUS_SB_CASEFOLD);
 334         decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
 335         hash = init_name_hash();
 336         astr = str->name;
 337         len = str->len;
 338         while (len > 0) {
 339                 size = asc2unichar(sb, astr, len, &c);
 340                 astr += size;
 341                 len -= size;
 342
 343                 if (decompose && (dstr = decompose_unichar(c, &dsize))) {
 344                         do {
 345                                 c2 = *dstr++;
 346                                 if (!casefold || (c2 = case_fold(c2)))
 347                                         hash = partial_name_hash(c2, hash);
 348                         } while (--dsize > 0);
 349                 } else {
 350                         c2 = c;
 351                         if (!casefold || (c2 = case_fold(c2)))
 352                                 hash = partial_name_hash(c2, hash);
 353                 }
 354         }
 355         str->hash = end_name_hash(hash);
 356
 357         return 0;
 358 }
 359
 360 /*
 361  * Compare strings with HFS+ filename ordering.
 362  * Composed unicode characters are decomposed and case-folding is performed
 363  * if the appropriate bits are (un)set on the superblock.
 364  */
 365 int hfsplus_compare_dentry(struct dentry *dentry, struct qstr *s1, struct qstr *s2)
 366 {
 367         struct super_block *sb = dentry->d_sb;
 368         int casefold, decompose, size;
 369         int dsize1, dsize2, len1, len2;
 370         const u16 *dstr1, *dstr2;
 371         const char *astr1, *astr2;
 372         u16 c1, c2;
 373         wchar_t c;
 374
 375         casefold = (HFSPLUS_SB(sb).flags & HFSPLUS_SB_CASEFOLD);
 376         decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
 377         astr1 = s1->name;
 378         len1 = s1->len;
 379         astr2 = s2->name;
 380         len2 = s2->len;
 381         dsize1 = dsize2 = 0;
 382         dstr1 = dstr2 = NULL;
 383
 384         while (len1 > 0 && len2 > 0) {
 385                 if (!dsize1) {
 386                         size = asc2unichar(sb, astr1, len1, &c);
 387                         astr1 += size;
 388                         len1 -= size;
 389
 390                         if (!decompose || !(dstr1 = decompose_unichar(c, &dsize1))) {
 391                                 c1 = c;
 392                                 dstr1 = &c1;
 393                                 dsize1 = 1;
 394                         }
 395                 }
 396
 397                 if (!dsize2) {
 398                         size = asc2unichar(sb, astr2, len2, &c);
 399                         astr2 += size;
 400                         len2 -= size;
 401
 402                         if (!decompose || !(dstr2 = decompose_unichar(c, &dsize2))) {
 403                                 c2 = c;
 404                                 dstr2 = &c2;
 405                                 dsize2 = 1;
 406                         }
 407                 }
 408
 409                 c1 = *dstr1;
 410                 c2 = *dstr2;
 411                 if (casefold) {
 412                         if  (!(c1 = case_fold(c1))) {
 413                                 dstr1++;
 414                                 dsize1--;
 415                                 continue;
 416                         }
 417                         if (!(c2 = case_fold(c2))) {
 418                                 dstr2++;
 419                                 dsize2--;
 420                                 continue;
 421                         }
 422                 }
 423                 if (c1 < c2)
 424                         return -1;
 425                 else if (c1 > c2)
 426                         return 1;
 427
 428                 dstr1++;
 429                 dsize1--;
 430                 dstr2++;
 431                 dsize2--;
 432         }
 433
 434         if (len1 < len2)
 435                 return -1;
 436         if (len1 > len2)
 437                 return 1;
 438         return 0;
 439 }