Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 1 | /* Copyright 1998,2001-2003,2007-2009 Alain Knaff. |
| 2 | * This file is part of mtools. |
| 3 | * |
| 4 | * Mtools is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * Mtools is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with Mtools. If not, see <http://www.gnu.org/licenses/>. |
| 16 | */ |
| 17 | #include "sysincludes.h" |
| 18 | #include "vfat.h" |
| 19 | #include "dirCache.h" |
| 20 | #include "dirCacheP.h" |
| 21 | #include <assert.h> |
| 22 | |
| 23 | |
| 24 | #define BITS_PER_INT (sizeof(unsigned int) * 8) |
| 25 | |
| 26 | |
| 27 | static __inline__ uint32_t rol(uint32_t arg, int shift) |
| 28 | { |
| 29 | arg &= 0xffffffff; /* for 64 bit machines */ |
| 30 | return (arg << shift) | (arg >> (32 - shift)); |
| 31 | } |
| 32 | |
| 33 | |
| 34 | static uint32_t calcHash(wchar_t *name) |
| 35 | { |
| 36 | uint32_t hash; |
| 37 | unsigned int i; |
| 38 | wint_t c; |
| 39 | |
| 40 | hash = 0; |
| 41 | i = 0; |
| 42 | while(*name) { |
| 43 | /* rotate it */ |
| 44 | hash = rol(hash,5); /* a shift of 5 makes sure we spread quickly |
| 45 | * over the whole width, moreover, 5 is |
| 46 | * prime with 32, which makes sure that |
| 47 | * successive letters cannot cover each |
| 48 | * other easily */ |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 49 | c = towupper((wint_t)*name); |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 50 | hash ^= (c * (c+2)) ^ (i * (i+2)); |
| 51 | hash &= 0xffffffff; |
| 52 | i++; |
| 53 | name++; |
| 54 | } |
| 55 | hash = hash * (hash + 2); |
| 56 | /* the following two xors make sure all info is spread evenly over all |
| 57 | * bytes. Important if we only keep the low order bits later on */ |
| 58 | hash ^= (hash & 0xfff) << 12; |
| 59 | hash ^= (hash & 0xff000) << 24; |
| 60 | return hash; |
| 61 | } |
| 62 | |
| 63 | static unsigned int addBit(unsigned int *bitmap, |
| 64 | unsigned int hash, int checkOnly) |
| 65 | { |
| 66 | unsigned int bit; |
| 67 | int entry; |
| 68 | |
| 69 | bit = 1u << (hash % BITS_PER_INT); |
| 70 | entry = (hash / BITS_PER_INT) % DC_BITMAP_SIZE; |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 71 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 72 | if(checkOnly) |
| 73 | return bitmap[entry] & bit; |
| 74 | else { |
| 75 | bitmap[entry] |= bit; |
| 76 | return 1; |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | static int _addHash(dirCache_t *cache, unsigned int hash, int checkOnly) |
| 81 | { |
| 82 | return |
| 83 | addBit(cache->bm0, hash, checkOnly) && |
| 84 | addBit(cache->bm1, rol(hash,12), checkOnly) && |
| 85 | addBit(cache->bm2, rol(hash,24), checkOnly); |
| 86 | } |
| 87 | |
| 88 | |
| 89 | static void addNameToHash(dirCache_t *cache, wchar_t *name) |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 90 | { |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 91 | _addHash(cache, calcHash(name), 0); |
| 92 | } |
| 93 | |
| 94 | static void hashDce(dirCache_t *cache, dirCacheEntry_t *dce) |
| 95 | { |
| 96 | if(dce->beginSlot != cache->nrHashed) |
| 97 | return; |
| 98 | cache->nrHashed = dce->endSlot; |
| 99 | if(dce->longName) |
| 100 | addNameToHash(cache, dce->longName); |
| 101 | addNameToHash(cache, dce->shortName); |
| 102 | } |
| 103 | |
| 104 | int isHashed(dirCache_t *cache, wchar_t *name) |
| 105 | { |
| 106 | int ret; |
| 107 | |
| 108 | ret = _addHash(cache, calcHash(name), 1); |
| 109 | return ret; |
| 110 | } |
| 111 | |
| 112 | int growDirCache(dirCache_t *cache, unsigned int slot) |
| 113 | { |
| 114 | if((int) slot < 0) { |
| 115 | fprintf(stderr, "Bad slot %d\n", slot); |
| 116 | exit(1); |
| 117 | } |
| 118 | |
| 119 | if( cache->nr_entries <= slot) { |
| 120 | unsigned int i; |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 121 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 122 | cache->entries = realloc(cache->entries, |
| 123 | (slot+1) * 2 * |
| 124 | sizeof(dirCacheEntry_t *)); |
| 125 | if(!cache->entries) |
| 126 | return -1; |
| 127 | for(i= cache->nr_entries; i < (slot+1) * 2; i++) { |
| 128 | cache->entries[i] = 0; |
| 129 | } |
| 130 | cache->nr_entries = (slot+1) * 2; |
| 131 | } |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | dirCache_t *allocDirCache(Stream_t *Stream, unsigned int slot) |
| 136 | { |
| 137 | dirCache_t **dcp; |
| 138 | |
| 139 | if((int)slot < 0) { |
| 140 | fprintf(stderr, "Bad slot %d\n", slot); |
| 141 | exit(1); |
| 142 | } |
| 143 | |
| 144 | dcp = getDirCacheP(Stream); |
| 145 | if(!*dcp) { |
| 146 | *dcp = New(dirCache_t); |
| 147 | if(!*dcp) |
| 148 | return 0; |
| 149 | (*dcp)->entries = NewArray((slot+1)*2+5, dirCacheEntry_t *); |
| 150 | if(!(*dcp)->entries) { |
| 151 | free(*dcp); |
| 152 | return 0; |
| 153 | } |
| 154 | (*dcp)->nr_entries = (slot+1) * 2; |
| 155 | memset( (*dcp)->bm0, 0, sizeof((*dcp)->bm0)); |
| 156 | memset( (*dcp)->bm1, 0, sizeof((*dcp)->bm1)); |
| 157 | memset( (*dcp)->bm2, 0, sizeof((*dcp)->bm1)); |
| 158 | (*dcp)->nrHashed = 0; |
| 159 | } else |
| 160 | if(growDirCache(*dcp, slot) < 0) |
| 161 | return 0; |
| 162 | return *dcp; |
| 163 | } |
| 164 | |
| 165 | /* Free a range of entries. The range being cleared is always aligned |
| 166 | * on the begin of an entry. Entries which are cleared entirely are |
| 167 | * free'd. Entries which are cleared half-way (can only happen at end) |
| 168 | * are "shortened" by moving its beginSlot |
| 169 | * If this was a range representing space after end-mark, return beginning |
| 170 | * of range if it had been shortened in its lifetime (which means that end |
| 171 | * mark must have moved => may need to be rewritten) |
| 172 | */ |
| 173 | static int freeDirCacheRange(dirCache_t *cache, |
| 174 | unsigned int beginSlot, |
| 175 | unsigned int endSlot) |
| 176 | { |
| 177 | dirCacheEntry_t *entry; |
| 178 | unsigned int clearBegin; |
| 179 | unsigned int clearEnd; |
| 180 | unsigned int i; |
| 181 | |
| 182 | if(endSlot < beginSlot) { |
| 183 | fprintf(stderr, "Bad slots %d %d in free range\n", |
| 184 | beginSlot, endSlot); |
| 185 | exit(1); |
| 186 | } |
| 187 | |
| 188 | while(beginSlot < endSlot) { |
| 189 | entry = cache->entries[beginSlot]; |
| 190 | if(!entry) { |
| 191 | beginSlot++; |
| 192 | continue; |
| 193 | } |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 194 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 195 | /* Due to the way this is called, we _always_ de-allocate |
| 196 | * starting from beginning... */ |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 197 | #ifdef HAVE_ASSERT_H |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 198 | assert(entry->beginSlot == beginSlot); |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 199 | #endif |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 200 | clearEnd = entry->endSlot; |
| 201 | if(clearEnd > endSlot) |
| 202 | clearEnd = endSlot; |
| 203 | clearBegin = beginSlot; |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 204 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 205 | for(i = clearBegin; i <clearEnd; i++) |
| 206 | cache->entries[i] = 0; |
| 207 | |
| 208 | entry->beginSlot = clearEnd; |
| 209 | |
| 210 | if(entry->beginSlot == entry->endSlot) { |
| 211 | int needWriteEnd = 0; |
| 212 | if(entry->endMarkPos != -1 && |
| 213 | entry->endMarkPos < (int) beginSlot) |
| 214 | needWriteEnd = 1; |
| 215 | |
| 216 | if(entry->longName) |
| 217 | free(entry->longName); |
| 218 | if(entry->shortName) |
| 219 | free(entry->shortName); |
| 220 | free(entry); |
| 221 | if(needWriteEnd) { |
| 222 | return (int) beginSlot; |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | beginSlot = clearEnd; |
| 227 | } |
| 228 | return -1; |
| 229 | } |
| 230 | |
| 231 | static dirCacheEntry_t *allocDirCacheEntry(dirCache_t *cache, |
| 232 | unsigned int beginSlot, |
| 233 | unsigned int endSlot, |
| 234 | dirCacheEntryType_t type) |
| 235 | { |
| 236 | dirCacheEntry_t *entry; |
| 237 | unsigned int i; |
| 238 | |
| 239 | if(growDirCache(cache, endSlot) < 0) |
| 240 | return 0; |
| 241 | |
| 242 | entry = New(dirCacheEntry_t); |
| 243 | if(!entry) |
| 244 | return 0; |
| 245 | entry->type = type; |
| 246 | entry->longName = 0; |
| 247 | entry->shortName = 0; |
| 248 | entry->beginSlot = beginSlot; |
| 249 | entry->endSlot = endSlot; |
| 250 | entry->endMarkPos = -1; |
| 251 | |
| 252 | freeDirCacheRange(cache, beginSlot, endSlot); |
| 253 | for(i=beginSlot; i<endSlot; i++) { |
| 254 | cache->entries[i] = entry; |
| 255 | } |
| 256 | return entry; |
| 257 | } |
| 258 | |
| 259 | dirCacheEntry_t *addUsedEntry(dirCache_t *cache, |
| 260 | unsigned int beginSlot, |
| 261 | unsigned int endSlot, |
| 262 | wchar_t *longName, wchar_t *shortName, |
| 263 | struct directory *dir) |
| 264 | { |
| 265 | dirCacheEntry_t *entry; |
| 266 | |
| 267 | if(endSlot < beginSlot) { |
| 268 | fprintf(stderr, |
| 269 | "Bad slots %d %d in add used entry\n", |
| 270 | beginSlot, endSlot); |
| 271 | exit(1); |
| 272 | } |
| 273 | |
| 274 | |
| 275 | entry = allocDirCacheEntry(cache, beginSlot, endSlot, DCET_USED); |
| 276 | if(!entry) |
| 277 | return 0; |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 278 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 279 | entry->beginSlot = beginSlot; |
| 280 | entry->endSlot = endSlot; |
| 281 | if(longName) |
| 282 | entry->longName = wcsdup(longName); |
| 283 | entry->shortName = wcsdup(shortName); |
| 284 | entry->dir = *dir; |
| 285 | hashDce(cache, entry); |
| 286 | return entry; |
| 287 | } |
| 288 | |
| 289 | /* Try to merge free slot at position "slot" with slot at previous position |
| 290 | * After successful merge, both will point to a same DCE (the one which used |
| 291 | * to be previous) |
| 292 | * Only does something if both of these slots are actually free |
| 293 | */ |
| 294 | static void mergeFreeSlots(dirCache_t *cache, unsigned int slot) |
| 295 | { |
| 296 | dirCacheEntry_t *previous, *next; |
| 297 | unsigned int i; |
| 298 | |
| 299 | if(slot == 0) |
| 300 | return; |
| 301 | previous = cache->entries[slot-1]; |
| 302 | next = cache->entries[slot]; |
| 303 | if(next && next->type == DCET_FREE && |
| 304 | previous && previous->type == DCET_FREE) { |
| 305 | for(i=next->beginSlot; i < next->endSlot; i++) |
| 306 | cache->entries[i] = previous; |
| 307 | previous->endSlot = next->endSlot; |
| 308 | previous->endMarkPos = next->endMarkPos; |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 309 | free(next); |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 310 | } |
| 311 | } |
| 312 | |
| 313 | /* Create a free range extending from beginSlot to endSlot, and try to merge |
| 314 | * it with any neighboring free ranges */ |
| 315 | dirCacheEntry_t *addFreeEndEntry(dirCache_t *cache, |
| 316 | unsigned int beginSlot, |
| 317 | unsigned int endSlot, |
| 318 | int isAtEnd) |
| 319 | { |
| 320 | dirCacheEntry_t *entry; |
| 321 | |
| 322 | if(beginSlot < cache->nrHashed) |
| 323 | cache->nrHashed = beginSlot; |
| 324 | |
| 325 | if(endSlot < beginSlot) { |
| 326 | fprintf(stderr, "Bad slots %d %d in add free entry\n", |
| 327 | beginSlot, endSlot); |
| 328 | exit(1); |
| 329 | } |
| 330 | |
| 331 | if(endSlot == beginSlot) |
| 332 | return 0; |
| 333 | entry = allocDirCacheEntry(cache, beginSlot, endSlot, DCET_FREE); |
| 334 | if(isAtEnd) |
| 335 | entry->endMarkPos = (int) beginSlot; |
| 336 | mergeFreeSlots(cache, beginSlot); |
| 337 | mergeFreeSlots(cache, endSlot); |
| 338 | return cache->entries[beginSlot]; |
| 339 | } |
| 340 | |
| 341 | dirCacheEntry_t *addFreeEntry(dirCache_t *cache, |
| 342 | unsigned int beginSlot, |
| 343 | unsigned int endSlot) |
| 344 | { |
| 345 | return addFreeEndEntry(cache, beginSlot, endSlot, 0); |
| 346 | } |
| 347 | |
| 348 | dirCacheEntry_t *addEndEntry(dirCache_t *cache, unsigned int pos) |
| 349 | { |
| 350 | return allocDirCacheEntry(cache, pos, pos+1u, DCET_END); |
| 351 | } |
| 352 | |
| 353 | dirCacheEntry_t *lookupInDircache(dirCache_t *cache, unsigned int pos) |
| 354 | { |
| 355 | if(growDirCache(cache, pos+1) < 0) |
| 356 | return 0; |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 357 | return cache->entries[pos]; |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 358 | } |
| 359 | |
| 360 | void freeDirCache(Stream_t *Stream) |
| 361 | { |
| 362 | dirCache_t *cache, **dcp; |
| 363 | |
| 364 | dcp = getDirCacheP(Stream); |
| 365 | cache = *dcp; |
| 366 | if(cache) { |
| 367 | int n; |
| 368 | n=freeDirCacheRange(cache, 0, cache->nr_entries); |
| 369 | if(n >= 0) |
| 370 | low_level_dir_write_end(Stream, n); |
| 371 | free(cache); |
| 372 | *dcp = 0; |
| 373 | } |
| 374 | } |