LXR linux/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 */
  18static 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 */
  31int 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 */
  64int 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
 101static 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
 121int 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;
 237out:
 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 */
 246static 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. */
 266static 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
 289int 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 */
 323int 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 */
 365int 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}
 440