runtime/maptable.mm

   1 /*
   2  * Copyright (c) 1999-2003, 2005-2007 Apple Inc.  All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*      maptable.m
  24         Copyright 1990-1996 NeXT Software, Inc.
  25         Created by Bertrand Serlet, August 1990
  26  */
  27
  28
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <stdio.h>
  32
  33 #include "objc-private.h"
  34 #include "maptable.h"
  35 #include "hashtable2.h"
  36
  37
  38 /******         Macros and utilities    ****************************/
  39
  40 #if defined(DEBUG)
  41     #define INLINE
  42 #else
  43     #define INLINE inline
  44 #endif
  45
  46 typedef struct _MapPair {
  47     const void  *key;
  48     const void  *value;
  49 } MapPair;
  50
  51 static INLINE unsigned xorHash(unsigned hash) {
  52     unsigned xored = (hash & 0xffff) ^ (hash >> 16);
  53     return ((xored * 65521) + hash);
  54 }
  55
  56 static INLINE unsigned bucketOf(NXMapTable *table, const void *key) {
  57     unsigned    hash = (table->prototype->hash)(table, key);
  58     return hash & table->nbBucketsMinusOne;
  59 }
  60
  61 static INLINE int isEqual(NXMapTable *table, const void *key1, const void *key2) {
  62     return (key1 == key2) ? 1 : (table->prototype->isEqual)(table, key1, key2);
  63 }
  64
  65 static INLINE unsigned nextIndex(NXMapTable *table, unsigned index) {
  66     return (index + 1) & table->nbBucketsMinusOne;
  67 }
  68
  69 static INLINE void *allocBuckets(void *z, unsigned nb) {
  70     MapPair     *pairs = 1+(MapPair *)malloc_zone_malloc((malloc_zone_t *)z, ((nb+1) * sizeof(MapPair)));
  71     MapPair     *pair = pairs;
  72     while (nb--) { pair->key = NX_MAPNOTAKEY; pair->value = NULL; pair++; }
  73     return pairs;
  74 }
  75
  76 static INLINE void freeBuckets(void *p) {
  77     free(-1+(MapPair *)p);
  78 }
  79
  80 /*****          Global data and bootstrap       **********************/
  81
  82 static int isEqualPrototype (const void *info, const void *data1, const void *data2) {
  83     NXHashTablePrototype        *proto1 = (NXHashTablePrototype *) data1;
  84     NXHashTablePrototype        *proto2 = (NXHashTablePrototype *) data2;
  85
  86     return (proto1->hash == proto2->hash) && (proto1->isEqual == proto2->isEqual) && (proto1->free == proto2->free) && (proto1->style == proto2->style);
  87     };
  88
  89 static uintptr_t hashPrototype (const void *info, const void *data) {
  90     NXHashTablePrototype        *proto = (NXHashTablePrototype *) data;
  91
  92     return NXPtrHash(info, (void*)proto->hash) ^ NXPtrHash(info, (void*)proto->isEqual) ^ NXPtrHash(info, (void*)proto->free) ^ (uintptr_t) proto->style;
  93     };
  94
  95 static NXHashTablePrototype protoPrototype = {
  96     hashPrototype, isEqualPrototype, NXNoEffectFree, 0
  97 };
  98
  99 static NXHashTable *prototypes = NULL;
 100         /* table of all prototypes */
 101
 102 /****           Fundamentals Operations                 **************/
 103
 104 NXMapTable *NXCreateMapTableFromZone(NXMapTablePrototype prototype, unsigned capacity, void *z) {
 105     NXMapTable                  *table = (NXMapTable *)malloc_zone_malloc((malloc_zone_t *)z, sizeof(NXMapTable));
 106     NXMapTablePrototype         *proto;
 107     if (! prototypes) prototypes = NXCreateHashTable(protoPrototype, 0, NULL);
 108     if (! prototype.hash || ! prototype.isEqual || ! prototype.free || prototype.style) {
 109         _objc_inform("*** NXCreateMapTable: invalid creation parameters\n");
 110         return NULL;
 111     }
 112     proto = (NXMapTablePrototype *)NXHashGet(prototypes, &prototype);
 113     if (! proto) {
 114         proto = (NXMapTablePrototype *)malloc(sizeof(NXMapTablePrototype));
 115         *proto = prototype;
 116         (void)NXHashInsert(prototypes, proto);
 117     }
 118     table->prototype = proto; table->count = 0;
 119     table->nbBucketsMinusOne = exp2u(log2u(capacity)+1) - 1;
 120     table->buckets = allocBuckets(z, table->nbBucketsMinusOne + 1);
 121     return table;
 122 }
 123
 124 NXMapTable *NXCreateMapTable(NXMapTablePrototype prototype, unsigned capacity) {
 125     return NXCreateMapTableFromZone(prototype, capacity, malloc_default_zone());
 126 }
 127
 128 void NXFreeMapTable(NXMapTable *table) {
 129     NXResetMapTable(table);
 130     freeBuckets(table->buckets);
 131     free(table);
 132 }
 133
 134 void NXResetMapTable(NXMapTable *table) {
 135     MapPair     *pairs = (MapPair *)table->buckets;
 136     void        (*freeProc)(struct _NXMapTable *, void *, void *) = table->prototype->free;
 137     unsigned    index = table->nbBucketsMinusOne + 1;
 138     while (index--) {
 139         if (pairs->key != NX_MAPNOTAKEY) {
 140             freeProc(table, (void *)pairs->key, (void *)pairs->value);
 141             pairs->key = NX_MAPNOTAKEY; pairs->value = NULL;
 142         }
 143         pairs++;
 144     }
 145     table->count = 0;
 146 }
 147
 148 BOOL NXCompareMapTables(NXMapTable *table1, NXMapTable *table2) {
 149     if (table1 == table2) return YES;
 150     if (table1->count != table2->count) return NO;
 151     else {
 152         const void *key;
 153         const void *value;
 154         NXMapState      state = NXInitMapState(table1);
 155         while (NXNextMapState(table1, &state, &key, &value)) {
 156             if (NXMapMember(table2, key, (void**)&value) == NX_MAPNOTAKEY) return NO;
 157         }
 158         return YES;
 159     }
 160 }
 161
 162 unsigned NXCountMapTable(NXMapTable *table) { return table->count; }
 163
 164 static INLINE void *_NXMapMember(NXMapTable *table, const void *key, void **value) {
 165     MapPair     *pairs = (MapPair *)table->buckets;
 166     unsigned    index = bucketOf(table, key);
 167     MapPair     *pair = pairs + index;
 168     if (pair->key == NX_MAPNOTAKEY) return NX_MAPNOTAKEY;
 169     if (isEqual(table, pair->key, key)) {
 170         *value = (void *)pair->value;
 171         return (void *)pair->key;
 172     } else {
 173         unsigned        index2 = index;
 174         while ((index2 = nextIndex(table, index2)) != index) {
 175             pair = pairs + index2;
 176             if (pair->key == NX_MAPNOTAKEY) return NX_MAPNOTAKEY;
 177             if (isEqual(table, pair->key, key)) {
 178                 *value = (void *)pair->value;
 179                 return (void *)pair->key;
 180             }
 181         }
 182         return NX_MAPNOTAKEY;
 183     }
 184 }
 185
 186 void *NXMapMember(NXMapTable *table, const void *key, void **value) {
 187     return _NXMapMember(table, key, value);
 188 }
 189
 190 void *NXMapGet(NXMapTable *table, const void *key) {
 191     void        *value;
 192     return (_NXMapMember(table, key, &value) != NX_MAPNOTAKEY) ? value : NULL;
 193 }
 194
 195 static void _NXMapRehash(NXMapTable *table) {
 196     MapPair     *pairs = (MapPair *)table->buckets;
 197     MapPair     *pair = pairs;
 198     unsigned    numBuckets = table->nbBucketsMinusOne + 1;
 199     unsigned    index = numBuckets;
 200     unsigned    oldCount = table->count;
 201
 202     table->nbBucketsMinusOne = 2 * numBuckets - 1;
 203     table->count = 0;
 204     table->buckets = allocBuckets(malloc_zone_from_ptr(table), table->nbBucketsMinusOne + 1);
 205     while (index--) {
 206         if (pair->key != NX_MAPNOTAKEY) {
 207             (void)NXMapInsert(table, pair->key, pair->value);
 208         }
 209         pair++;
 210     }
 211     if (oldCount != table->count)
 212         _objc_inform("*** maptable: count differs after rehashing; probably indicates a broken invariant: there are x and y such as isEqual(x, y) is TRUE but hash(x) != hash (y)\n");
 213     freeBuckets(pairs);
 214 }
 215
 216 void *NXMapInsert(NXMapTable *table, const void *key, const void *value) {
 217     MapPair     *pairs = (MapPair *)table->buckets;
 218     unsigned    index = bucketOf(table, key);
 219     MapPair     *pair = pairs + index;
 220     if (key == NX_MAPNOTAKEY) {
 221         _objc_inform("*** NXMapInsert: invalid key: -1\n");
 222         return NULL;
 223     }
 224
 225     unsigned numBuckets = table->nbBucketsMinusOne + 1;
 226
 227     if (pair->key == NX_MAPNOTAKEY) {
 228         pair->key = key; pair->value = value;
 229         table->count++;
 230         if (table->count * 4 > numBuckets * 3) _NXMapRehash(table);
 231         return NULL;
 232     }
 233
 234     if (isEqual(table, pair->key, key)) {
 235         const void      *old = pair->value;
 236         if (old != value) pair->value = value;/* avoid writing unless needed! */
 237         return (void *)old;
 238     } else if (table->count == numBuckets) {
 239         /* no room: rehash and retry */
 240         _NXMapRehash(table);
 241         return NXMapInsert(table, key, value);
 242     } else {
 243         unsigned        index2 = index;
 244         while ((index2 = nextIndex(table, index2)) != index) {
 245             pair = pairs + index2;
 246             if (pair->key == NX_MAPNOTAKEY) {
 247               pair->key = key; pair->value = value;
 248                 table->count++;
 249                 if (table->count * 4 > numBuckets * 3) _NXMapRehash(table);
 250                 return NULL;
 251             }
 252             if (isEqual(table, pair->key, key)) {
 253                 const void      *old = pair->value;
 254                 if (old != value) pair->value = value;/* avoid writing unless needed! */
 255                 return (void *)old;
 256             }
 257         }
 258         /* no room: can't happen! */
 259         _objc_inform("**** NXMapInsert: bug\n");
 260         return NULL;
 261     }
 262 }
 263
 264 static int mapRemove = 0;
 265
 266 void *NXMapRemove(NXMapTable *table, const void *key) {
 267     MapPair     *pairs = (MapPair *)table->buckets;
 268     unsigned    index = bucketOf(table, key);
 269     MapPair     *pair = pairs + index;
 270     unsigned    chain = 1; /* number of non-nil pairs in a row */
 271     int         found = 0;
 272     const void  *old = NULL;
 273     if (pair->key == NX_MAPNOTAKEY) return NULL;
 274     mapRemove ++;
 275     /* compute chain */
 276     {
 277         unsigned        index2 = index;
 278         if (isEqual(table, pair->key, key)) {found ++; old = pair->value; }
 279         while ((index2 = nextIndex(table, index2)) != index) {
 280             pair = pairs + index2;
 281             if (pair->key == NX_MAPNOTAKEY) break;
 282             if (isEqual(table, pair->key, key)) {found ++; old = pair->value; }
 283             chain++;
 284         }
 285     }
 286     if (! found) return NULL;
 287     if (found != 1) _objc_inform("**** NXMapRemove: incorrect table\n");
 288     /* remove then reinsert */
 289     {
 290         MapPair buffer[16];
 291         MapPair *aux = (chain > 16) ? (MapPair *)malloc(sizeof(MapPair)*(chain-1)) : buffer;
 292         unsigned        auxnb = 0;
 293         int     nb = chain;
 294         unsigned        index2 = index;
 295         while (nb--) {
 296             pair = pairs + index2;
 297             if (! isEqual(table, pair->key, key)) aux[auxnb++] = *pair;
 298             pair->key = NX_MAPNOTAKEY; pair->value = NULL;
 299             index2 = nextIndex(table, index2);
 300         }
 301         table->count -= chain;
 302         if (auxnb != chain-1) _objc_inform("**** NXMapRemove: bug\n");
 303         while (auxnb--) NXMapInsert(table, aux[auxnb].key, aux[auxnb].value);
 304         if (chain > 16) free(aux);
 305     }
 306     return (void *)old;
 307 }
 308
 309 NXMapState NXInitMapState(NXMapTable *table) {
 310     NXMapState  state;
 311     state.index = table->nbBucketsMinusOne + 1;
 312     return state;
 313 }
 314
 315 int NXNextMapState(NXMapTable *table, NXMapState *state, const void **key, const void **value) {
 316     MapPair     *pairs = (MapPair *)table->buckets;
 317     while (state->index--) {
 318         MapPair *pair = pairs + state->index;
 319         if (pair->key != NX_MAPNOTAKEY) {
 320             *key = pair->key; *value = pair->value;
 321             return YES;
 322         }
 323     }
 324     return NO;
 325 }
 326
 327
 328 /***********************************************************************
 329 * NXMapKeyCopyingInsert
 330 * Like NXMapInsert, but strdups the key if necessary.
 331 * Used to prevent stale pointers when bundles are unloaded.
 332 **********************************************************************/
 333 void *NXMapKeyCopyingInsert(NXMapTable *table, const void *key, const void *value)
 334 {
 335     void *realKey;
 336     void *realValue = NULL;
 337
 338     if ((realKey = NXMapMember(table, key, &realValue)) != NX_MAPNOTAKEY) {
 339         // key DOES exist in table - use table's key for insertion
 340     } else {
 341         // key DOES NOT exist in table - copy the new key before insertion
 342         realKey = (void *)strdupIfMutable((char *)key);
 343     }
 344     return NXMapInsert(table, realKey, value);
 345 }
 346
 347
 348 /***********************************************************************
 349 * NXMapKeyFreeingRemove
 350 * Like NXMapRemove, but frees the existing key if necessary.
 351 * Used to prevent stale pointers when bundles are unloaded.
 352 **********************************************************************/
 353 void *NXMapKeyFreeingRemove(NXMapTable *table, const void *key)
 354 {
 355     void *realKey;
 356     void *realValue = NULL;
 357
 358     if ((realKey = NXMapMember(table, key, &realValue)) != NX_MAPNOTAKEY) {
 359         // key DOES exist in table - remove pair and free key
 360         realValue = NXMapRemove(table, realKey);
 361         // free the key from the table, not necessarily the one given
 362         freeIfMutable((char *)realKey);
 363         return realValue;
 364     } else {
 365         // key DOES NOT exist in table - nothing to do
 366         return NULL;
 367     }
 368 }
 369
 370
 371 /****           Conveniences            *************************************/
 372
 373 static unsigned _mapPtrHash(NXMapTable *table, const void *key) {
 374 #ifdef __LP64__
 375     return (unsigned)(((uintptr_t)key) >> 3);
 376 #else
 377     return ((uintptr_t)key) >> 2;
 378 #endif
 379 }
 380
 381 static unsigned _mapStrHash(NXMapTable *table, const void *key) {
 382     unsigned            hash = 0;
 383     unsigned char       *s = (unsigned char *)key;
 384     /* unsigned to avoid a sign-extend */
 385     /* unroll the loop */
 386     if (s) for (; ; ) {
 387         if (*s == '\0') break;
 388         hash ^= *s++;
 389         if (*s == '\0') break;
 390         hash ^= *s++ << 8;
 391         if (*s == '\0') break;
 392         hash ^= *s++ << 16;
 393         if (*s == '\0') break;
 394         hash ^= *s++ << 24;
 395     }
 396     return xorHash(hash);
 397 }
 398
 399 static int _mapPtrIsEqual(NXMapTable *table, const void *key1, const void *key2) {
 400     return key1 == key2;
 401 }
 402
 403 static int _mapStrIsEqual(NXMapTable *table, const void *key1, const void *key2) {
 404     if (key1 == key2) return YES;
 405     if (! key1) return ! strlen ((char *) key2);
 406     if (! key2) return ! strlen ((char *) key1);
 407     if (((char *) key1)[0] != ((char *) key2)[0]) return NO;
 408     return (strcmp((char *) key1, (char *) key2)) ? NO : YES;
 409 }
 410
 411 static void _mapNoFree(NXMapTable *table, void *key, void *value) {}
 412
 413 const NXMapTablePrototype NXPtrValueMapPrototype = {
 414     _mapPtrHash, _mapPtrIsEqual, _mapNoFree, 0
 415 };
 416
 417 const NXMapTablePrototype NXStrValueMapPrototype = {
 418     _mapStrHash, _mapStrIsEqual, _mapNoFree, 0
 419 };
 420
 421
 422 #if !__OBJC2__  &&  !TARGET_OS_WIN32
 423
 424 /* This only works with class Object, which is unavailable. */
 425
 426 /* Method prototypes */
 427 @interface DoesNotExist
 428 + (id)class;
 429 + (id)initialize;
 430 - (id)description;
 431 - (const char *)UTF8String;
 432 - (unsigned long)hash;
 433 - (BOOL)isEqual:(id)object;
 434 - (void)free;
 435 @end
 436
 437 static unsigned _mapObjectHash(NXMapTable *table, const void *key) {
 438     return [(id)key hash];
 439 }
 440
 441 static int _mapObjectIsEqual(NXMapTable *table, const void *key1, const void *key2) {
 442     return [(id)key1 isEqual:(id)key2];
 443 }
 444
 445 static void _mapObjectFree(NXMapTable *table, void *key, void *value) {
 446     [(id)key free];
 447 }
 448
 449 const NXMapTablePrototype NXObjectMapPrototype = {
 450     _mapObjectHash, _mapObjectIsEqual, _mapObjectFree, 0
 451 };
 452
 453 #endif