libkern/c++/OSSymbol.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* IOSymbol.cpp created by gvdl on Fri 1998-11-17 */
  23
  24 #include <string.h>
  25 #include <sys/cdefs.h>
  26
  27 __BEGIN_DECLS
  28 #include <kern/lock.h>
  29 __END_DECLS
  30
  31 #include <libkern/c++/OSSymbol.h>
  32 #include <libkern/c++/OSLib.h>
  33 #include <string.h>
  34
  35 #define super OSString
  36
  37 typedef struct { int i, j; } OSSymbolPoolState;
  38
  39 #if OSALLOCDEBUG
  40 extern "C" {
  41     extern int debug_container_malloc_size;
  42 };
  43 #define ACCUMSIZE(s) do { debug_container_malloc_size += (s); } while(0)
  44 #else
  45 #define ACCUMSIZE(s)
  46 #endif
  47
  48 class OSSymbolPool
  49 {
  50 private:
  51     static const unsigned int kInitBucketCount = 16;
  52
  53     typedef struct { unsigned int count; OSSymbol **symbolP; } Bucket;
  54
  55     Bucket *buckets;
  56     unsigned int nBuckets;
  57     unsigned int count;
  58     mutex_t *poolGate;
  59
  60     static inline void hashSymbol(const char *s,
  61                                   unsigned int *hashP,
  62                                   unsigned int *lenP)
  63     {
  64         unsigned int hash = 0;
  65         unsigned int len = 0;
  66
  67         /* Unroll the loop. */
  68         for (;;) {
  69             if (!*s) break; len++; hash ^= *s++;
  70             if (!*s) break; len++; hash ^= *s++ <<  8;
  71             if (!*s) break; len++; hash ^= *s++ << 16;
  72             if (!*s) break; len++; hash ^= *s++ << 24;
  73         }
  74         *lenP = len;
  75         *hashP = hash;
  76     }
  77
  78     static unsigned long log2(unsigned int x);
  79     static unsigned long exp2ml(unsigned int x);
  80
  81     void reconstructSymbols();
  82
  83 public:
  84     static void *operator new(size_t size);
  85     static void operator delete(void *mem, size_t size);
  86
  87     OSSymbolPool() { };
  88     OSSymbolPool(const OSSymbolPool *old);
  89     virtual ~OSSymbolPool();
  90
  91     bool init();
  92
  93     inline void closeGate() { mutex_lock(poolGate); };
  94     inline void openGate()  { mutex_unlock(poolGate); };
  95
  96     OSSymbol *findSymbol(const char *cString, OSSymbol ***replace) const;
  97     OSSymbol *insertSymbol(OSSymbol *sym);
  98     void removeSymbol(OSSymbol *sym);
  99
 100     OSSymbolPoolState initHashState();
 101     OSSymbol *nextHashState(OSSymbolPoolState *stateP);
 102 };
 103
 104 void * OSSymbolPool::operator new(size_t size)
 105 {
 106     void *mem = (void *)kalloc(size);
 107     ACCUMSIZE(size);
 108     assert(mem);
 109     bzero(mem, size);
 110
 111     return mem;
 112 }
 113
 114 void OSSymbolPool::operator delete(void *mem, size_t size)
 115 {
 116     kfree((vm_offset_t)mem, size);
 117     ACCUMSIZE(-size);
 118 }
 119
 120 bool OSSymbolPool::init()
 121 {
 122     count = 0;
 123     nBuckets = exp2ml(1 + log2(kInitBucketCount));
 124     buckets = (Bucket *) kalloc(nBuckets * sizeof(Bucket));
 125     ACCUMSIZE(nBuckets * sizeof(Bucket));
 126     if (!buckets)
 127         return false;
 128
 129     bzero(buckets, nBuckets * sizeof(Bucket));
 130
 131     poolGate = mutex_alloc(0);
 132
 133     return poolGate != 0;
 134 }
 135
 136 OSSymbolPool::OSSymbolPool(const OSSymbolPool *old)
 137 {
 138     count = old->count;
 139     nBuckets = old->nBuckets;
 140     buckets = old->buckets;
 141
 142     poolGate = 0;       // Do not duplicate the poolGate
 143 }
 144
 145 OSSymbolPool::~OSSymbolPool()
 146 {
 147     if (buckets) {
 148         kfree((vm_offset_t)buckets, nBuckets * sizeof(Bucket));
 149         ACCUMSIZE(-(nBuckets * sizeof(Bucket)));
 150     }
 151
 152     if (poolGate)
 153         kfree((vm_offset_t) poolGate, 36 * 4);
 154 }
 155
 156 unsigned long OSSymbolPool::log2(unsigned int x)
 157 {
 158     unsigned long i;
 159
 160     for (i = 0; x > 1 ; i++)
 161         x >>= 1;
 162     return i;
 163 }
 164
 165 unsigned long OSSymbolPool::exp2ml(unsigned int x)
 166 {
 167     return (1 << x) - 1;
 168 }
 169
 170 OSSymbolPoolState OSSymbolPool::initHashState()
 171 {
 172     OSSymbolPoolState newState = { nBuckets, 0 };
 173     return newState;
 174 }
 175
 176 OSSymbol *OSSymbolPool::nextHashState(OSSymbolPoolState *stateP)
 177 {
 178     Bucket *thisBucket = &buckets[stateP->i];
 179
 180     while (!stateP->j) {
 181         if (!stateP->i)
 182             return 0;
 183         stateP->i--;
 184         thisBucket--;
 185         stateP->j = thisBucket->count;
 186     }
 187
 188     stateP->j--;
 189     if (thisBucket->count == 1)
 190         return (OSSymbol *) thisBucket->symbolP;
 191     else
 192         return thisBucket->symbolP[stateP->j];
 193 }
 194
 195 void OSSymbolPool::reconstructSymbols()
 196 {
 197     OSSymbolPool old(this);
 198     OSSymbol *insert;
 199     OSSymbolPoolState state;
 200
 201     nBuckets += nBuckets + 1;
 202     count = 0;
 203     buckets = (Bucket *) kalloc(nBuckets * sizeof(Bucket));
 204     ACCUMSIZE(nBuckets * sizeof(Bucket));
 205     /* @@@ gvdl: Zero test and panic if can't set up pool */
 206     bzero(buckets, nBuckets * sizeof(Bucket));
 207
 208     state = old.initHashState();
 209     while ( (insert = old.nextHashState(&state)) )
 210         insertSymbol(insert);
 211 }
 212
 213 OSSymbol *OSSymbolPool::findSymbol(const char *cString, OSSymbol ***replace) const
 214 {
 215     Bucket *thisBucket;
 216     unsigned int j, inLen, hash;
 217     OSSymbol *probeSymbol, **list;
 218
 219     hashSymbol(cString, &hash, &inLen); inLen++;
 220     thisBucket = &buckets[hash % nBuckets];
 221     j = thisBucket->count;
 222
 223     *replace = NULL;
 224
 225     if (!j)
 226         return 0;
 227
 228     if (j == 1) {
 229         probeSymbol = (OSSymbol *) thisBucket->symbolP;
 230
 231         if (inLen == probeSymbol->length
 232         &&  (strcmp(probeSymbol->string, cString) == 0)) {
 233             probeSymbol->retain();
 234             if (probeSymbol->getRetainCount() != 0xffff)
 235                 return probeSymbol;
 236             else
 237                 // replace this one
 238                 *replace = (OSSymbol **) &thisBucket->symbolP;
 239         }
 240         return 0;
 241     }
 242
 243     for (list = thisBucket->symbolP; j--; list++) {
 244         probeSymbol = *list;
 245         if (inLen == probeSymbol->length
 246         &&  (strcmp(probeSymbol->string, cString) == 0)) {
 247             probeSymbol->retain();
 248             if (probeSymbol->getRetainCount() != 0xffff)
 249                 return probeSymbol;
 250             else
 251                 // replace this one
 252                 *replace = list;
 253         }
 254     }
 255
 256     return 0;
 257 }
 258
 259 OSSymbol *OSSymbolPool::insertSymbol(OSSymbol *sym)
 260 {
 261     const char *cString = sym->string;
 262     Bucket *thisBucket;
 263     unsigned int j, inLen, hash;
 264     OSSymbol *probeSymbol, **list;
 265
 266     hashSymbol(cString, &hash, &inLen); inLen++;
 267     thisBucket = &buckets[hash % nBuckets];
 268     j = thisBucket->count;
 269
 270     if (!j) {
 271         thisBucket->symbolP = (OSSymbol **) sym;
 272         thisBucket->count++;
 273         count++;
 274         return 0;
 275     }
 276
 277     if (j == 1) {
 278         probeSymbol = (OSSymbol *) thisBucket->symbolP;
 279
 280         if (inLen == probeSymbol->length
 281         &&  strcmp(probeSymbol->string, cString) == 0)
 282             return probeSymbol;
 283
 284         list = (OSSymbol **) kalloc(2 * sizeof(OSSymbol *));
 285         ACCUMSIZE(2 * sizeof(OSSymbol *));
 286         /* @@@ gvdl: Zero test and panic if can't set up pool */
 287         list[0] = sym;
 288         list[1] = probeSymbol;
 289         thisBucket->symbolP = list;
 290         thisBucket->count++;
 291         count++;
 292         if (count > nBuckets)
 293             reconstructSymbols();
 294
 295         return 0;
 296     }
 297
 298     for (list = thisBucket->symbolP; j--; list++) {
 299         probeSymbol = *list;
 300         if (inLen == probeSymbol->length
 301         &&  strcmp(probeSymbol->string, cString) == 0)
 302             return probeSymbol;
 303     }
 304
 305     j = thisBucket->count++;
 306     count++;
 307     list = (OSSymbol **) kalloc(thisBucket->count * sizeof(OSSymbol *));
 308     ACCUMSIZE(thisBucket->count * sizeof(OSSymbol *));
 309     /* @@@ gvdl: Zero test and panic if can't set up pool */
 310     list[0] = sym;
 311     bcopy(thisBucket->symbolP, list + 1, j * sizeof(OSSymbol *));
 312     kfree((vm_offset_t)thisBucket->symbolP, j * sizeof(OSSymbol *));
 313     ACCUMSIZE(-(j * sizeof(OSSymbol *)));
 314     thisBucket->symbolP = list;
 315     if (count > nBuckets)
 316         reconstructSymbols();
 317
 318     return 0;
 319 }
 320
 321 void OSSymbolPool::removeSymbol(OSSymbol *sym)
 322 {
 323     Bucket *thisBucket;
 324     unsigned int j, inLen, hash;
 325     OSSymbol *probeSymbol, **list;
 326
 327     hashSymbol(sym->string, &hash, &inLen); inLen++;
 328     thisBucket = &buckets[hash % nBuckets];
 329     j = thisBucket->count;
 330     list = thisBucket->symbolP;
 331
 332     if (!j)
 333         return;
 334
 335     if (j == 1) {
 336         probeSymbol = (OSSymbol *) list;
 337
 338         if (probeSymbol == sym) {
 339             thisBucket->symbolP = 0;
 340             count--;
 341             thisBucket->count--;
 342             return;
 343         }
 344         return;
 345     }
 346
 347     if (j == 2) {
 348         probeSymbol = list[0];
 349         if (probeSymbol == sym) {
 350             thisBucket->symbolP = (OSSymbol **) list[1];
 351             kfree((vm_offset_t)list, 2 * sizeof(OSSymbol *));
 352             ACCUMSIZE(-(2 * sizeof(OSSymbol *)));
 353             count--;
 354             thisBucket->count--;
 355             return;
 356         }
 357
 358         probeSymbol = list[1];
 359         if (probeSymbol == sym) {
 360             thisBucket->symbolP = (OSSymbol **) list[0];
 361             kfree((vm_offset_t)list, 2 * sizeof(OSSymbol *));
 362             ACCUMSIZE(-(2 * sizeof(OSSymbol *)));
 363             count--;
 364             thisBucket->count--;
 365             return;
 366         }
 367         return;
 368     }
 369
 370     for (; j--; list++) {
 371         probeSymbol = *list;
 372         if (probeSymbol == sym) {
 373
 374             list = (OSSymbol **)
 375                 kalloc((thisBucket->count-1) * sizeof(OSSymbol *));
 376             ACCUMSIZE((thisBucket->count-1) * sizeof(OSSymbol *));
 377             if (thisBucket->count-1 != j)
 378                 bcopy(thisBucket->symbolP, list,
 379                       (thisBucket->count-1-j) * sizeof(OSSymbol *));
 380             if (j)
 381                 bcopy(thisBucket->symbolP + thisBucket->count-j,
 382                       list + thisBucket->count-1-j,
 383                       j * sizeof(OSSymbol *));
 384             kfree((vm_offset_t)thisBucket->symbolP, thisBucket->count * sizeof(OSSymbol *));
 385             ACCUMSIZE(-(thisBucket->count * sizeof(OSSymbol *)));
 386             thisBucket->symbolP = list;
 387             count--;
 388             thisBucket->count--;
 389             return;
 390         }
 391     }
 392 }
 393
 394 /*
 395  *********************************************************************
 396  * From here on we are actually implementing the OSSymbol class
 397  *********************************************************************
 398  */
 399 OSDefineMetaClassAndStructorsWithInit(OSSymbol, OSString,
 400                                       OSSymbol::initialize())
 401 OSMetaClassDefineReservedUnused(OSSymbol, 0);
 402 OSMetaClassDefineReservedUnused(OSSymbol, 1);
 403 OSMetaClassDefineReservedUnused(OSSymbol, 2);
 404 OSMetaClassDefineReservedUnused(OSSymbol, 3);
 405 OSMetaClassDefineReservedUnused(OSSymbol, 4);
 406 OSMetaClassDefineReservedUnused(OSSymbol, 5);
 407 OSMetaClassDefineReservedUnused(OSSymbol, 6);
 408 OSMetaClassDefineReservedUnused(OSSymbol, 7);
 409
 410 static OSSymbolPool *pool;
 411
 412 void OSSymbol::initialize()
 413 {
 414     pool = new OSSymbolPool;
 415     assert(pool);
 416
 417     if (!pool->init()) {
 418         delete pool;
 419         assert(false);
 420     };
 421 }
 422
 423 bool OSSymbol::initWithCStringNoCopy(const char *) { return false; }
 424 bool OSSymbol::initWithCString(const char *) { return false; }
 425 bool OSSymbol::initWithString(const OSString *) { return false; }
 426
 427 const OSSymbol *OSSymbol::withString(const OSString *aString)
 428 {
 429     // This string may be a OSSymbol already, cheap check.
 430     if (OSDynamicCast(OSSymbol, aString)) {
 431         aString->retain();
 432         return (const OSSymbol *) aString;
 433     }
 434     else if (((const OSSymbol *) aString)->flags & kOSStringNoCopy)
 435         return OSSymbol::withCStringNoCopy(aString->getCStringNoCopy());
 436     else
 437         return OSSymbol::withCString(aString->getCStringNoCopy());
 438 }
 439
 440 const OSSymbol *OSSymbol::withCString(const char *cString)
 441 {
 442     OSSymbol **replace;
 443
 444     pool->closeGate();
 445
 446     OSSymbol *newSymb = pool->findSymbol(cString, &replace);
 447     if (!newSymb && (newSymb = new OSSymbol) ) {
 448         if (newSymb->OSString::initWithCString(cString)) {
 449             if (replace)
 450                 *replace = newSymb;
 451             else
 452                 pool->insertSymbol(newSymb);
 453         } else {
 454             newSymb->OSString::free();
 455             newSymb = 0;
 456         }
 457     }
 458     pool->openGate();
 459
 460     return newSymb;
 461 }
 462
 463 const OSSymbol *OSSymbol::withCStringNoCopy(const char *cString)
 464 {
 465     OSSymbol **replace;
 466
 467     pool->closeGate();
 468
 469     OSSymbol *newSymb = pool->findSymbol(cString, &replace);
 470     if (!newSymb && (newSymb = new OSSymbol) ) {
 471         if (newSymb->OSString::initWithCStringNoCopy(cString)) {
 472             if (replace)
 473                 *replace = newSymb;
 474             else
 475                 pool->insertSymbol(newSymb);
 476         } else {
 477             newSymb->OSString::free();
 478             newSymb = 0;
 479         }
 480     }
 481     pool->openGate();
 482
 483     return newSymb;
 484 }
 485
 486 void OSSymbol::checkForPageUnload(void *startAddr, void *endAddr)
 487 {
 488     OSSymbol *probeSymbol;
 489     OSSymbolPoolState state;
 490
 491     pool->closeGate();
 492     state = pool->initHashState();
 493     while ( (probeSymbol = pool->nextHashState(&state)) ) {
 494         if (probeSymbol->string >= startAddr && probeSymbol->string < endAddr) {
 495             const char *oldString = probeSymbol->string;
 496
 497             probeSymbol->string = (char *) kalloc(probeSymbol->length);
 498             ACCUMSIZE(probeSymbol->length);
 499             bcopy(oldString, probeSymbol->string, probeSymbol->length);
 500             probeSymbol->flags &= ~kOSStringNoCopy;
 501         }
 502     }
 503     pool->openGate();
 504 }
 505
 506 void OSSymbol::free()
 507 {
 508     pool->closeGate();
 509     pool->removeSymbol(this);
 510     pool->openGate();
 511
 512     super::free();
 513 }
 514
 515 bool OSSymbol::isEqualTo(const char *aCString) const
 516 {
 517     return super::isEqualTo(aCString);
 518 }
 519
 520 bool OSSymbol::isEqualTo(const OSSymbol *aSymbol) const
 521 {
 522     return aSymbol == this;
 523 }
 524
 525 bool OSSymbol::isEqualTo(const OSMetaClassBase *obj) const
 526 {
 527     OSSymbol *  sym;
 528     OSString *  str;
 529
 530     if ((sym = OSDynamicCast(OSSymbol, obj)))
 531         return isEqualTo(sym);
 532     else if ((str = OSDynamicCast(OSString, obj)))
 533         return super::isEqualTo(str);
 534     else
 535         return false;
 536 }