runtime/hashtable2.m

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26         hashtable2.m
  27         Copyright 1989-1996 NeXT Software, Inc.
  28         Created by Bertrand Serlet, Feb 89
  29  */
  30
  31 #import <objc/hashtable2.h>
  32 #import "objc-private.h"
  33
  34 /* Is this in the right spot ? <jf> */
  35 #if defined(__osf__)
  36     #include <stdarg.h>
  37 #endif
  38
  39     #import <mach/mach.h>
  40     #import <pthread.h>
  41
  42 /* In order to improve efficiency, buckets contain a pointer to an array or directly the data when the array size is 1 */
  43 typedef union {
  44     const void  *one;
  45     const void  **many;
  46     } oneOrMany;
  47     /* an optimization consists of storing directly data when count = 1 */
  48
  49 typedef struct  {
  50     unsigned    count;
  51     oneOrMany   elements;
  52     } HashBucket;
  53     /* private data structure; may change */
  54
  55 /*************************************************************************
  56  *
  57  *      Macros and utilities
  58  *
  59  *************************************************************************/
  60
  61 static unsigned log2 (unsigned x) { return (x<2) ? 0 : log2 (x>>1)+1; };
  62
  63 static unsigned exp2m1 (unsigned x) { return (1 << x) - 1; };
  64
  65 #define PTRSIZE         sizeof(void *)
  66
  67 #define ALLOCTABLE(z)   ((NXHashTable *) malloc_zone_malloc (z,sizeof (NXHashTable)))
  68 #define ALLOCBUCKETS(z,nb)((HashBucket *) malloc_zone_calloc (z, nb, sizeof (HashBucket)))
  69 #define ALLOCPAIRS(z,nb) ((const void **) malloc_zone_calloc (z, nb, sizeof (void *)))
  70
  71 /* iff necessary this modulo can be optimized since the nbBuckets is of the form 2**n-1 */
  72 #define BUCKETOF(table, data) (((HashBucket *)table->buckets)+((*table->prototype->hash)(table->info, data) % table->nbBuckets))
  73
  74 #define ISEQUAL(table, data1, data2) ((data1 == data2) || (*table->prototype->isEqual)(table->info, data1, data2))
  75         /* beware of double evaluation */
  76
  77 /*************************************************************************
  78  *
  79  *      Global data and bootstrap
  80  *
  81  *************************************************************************/
  82
  83 static int isEqualPrototype (const void *info, const void *data1, const void *data2) {
  84     NXHashTablePrototype        *proto1 = (NXHashTablePrototype *) data1;
  85     NXHashTablePrototype        *proto2 = (NXHashTablePrototype *) data2;
  86
  87     return (proto1->hash == proto2->hash) && (proto1->isEqual == proto2->isEqual) && (proto1->free == proto2->free) && (proto1->style == proto2->style);
  88     };
  89
  90 static uarith_t hashPrototype (const void *info, const void *data) {
  91     NXHashTablePrototype        *proto = (NXHashTablePrototype *) data;
  92
  93     return NXPtrHash(info, proto->hash) ^ NXPtrHash(info, proto->isEqual) ^ NXPtrHash(info, proto->free) ^ (uarith_t) proto->style;
  94     };
  95
  96 void NXNoEffectFree (const void *info, void *data) {};
  97
  98 static NXHashTablePrototype protoPrototype = {
  99     hashPrototype, isEqualPrototype, NXNoEffectFree, 0
 100     };
 101
 102 static NXHashTable *prototypes = NULL;
 103         /* table of all prototypes */
 104
 105 static void bootstrap (void) {
 106     free(malloc(8));
 107     prototypes = ALLOCTABLE (malloc_default_zone());
 108     prototypes->prototype = &protoPrototype;
 109     prototypes->count = 1;
 110     prototypes->nbBuckets = 1; /* has to be 1 so that the right bucket is 0 */
 111     prototypes->buckets = ALLOCBUCKETS(malloc_default_zone(),  1);
 112     prototypes->info = NULL;
 113     ((HashBucket *) prototypes->buckets)[0].count = 1;
 114     ((HashBucket *) prototypes->buckets)[0].elements.one = &protoPrototype;
 115     };
 116
 117 int NXPtrIsEqual (const void *info, const void *data1, const void *data2) {
 118     return data1 == data2;
 119     };
 120
 121 /*************************************************************************
 122  *
 123  *      On z'y va
 124  *
 125  *************************************************************************/
 126
 127 NXHashTable *NXCreateHashTable (NXHashTablePrototype prototype, unsigned capacity, const void *info) {
 128     return NXCreateHashTableFromZone(prototype, capacity, info, malloc_default_zone());
 129 }
 130
 131 NXHashTable *NXCreateHashTableFromZone (NXHashTablePrototype prototype, unsigned capacity, const void *info, void *z) {
 132     NXHashTable                 *table;
 133     NXHashTablePrototype        *proto;
 134
 135     table = ALLOCTABLE(z);
 136     if (! prototypes) bootstrap ();
 137     if (! prototype.hash) prototype.hash = NXPtrHash;
 138     if (! prototype.isEqual) prototype.isEqual = NXPtrIsEqual;
 139     if (! prototype.free) prototype.free = NXNoEffectFree;
 140     if (prototype.style) {
 141         _objc_syslog ("*** NXCreateHashTable: invalid style\n");
 142         return NULL;
 143         };
 144     proto = NXHashGet (prototypes, &prototype);
 145     if (! proto) {
 146         proto
 147         = (NXHashTablePrototype *) malloc_zone_malloc (malloc_default_zone(),
 148                                                  sizeof (NXHashTablePrototype));
 149         bcopy ((const char*)&prototype, (char*)proto, sizeof (NXHashTablePrototype));
 150         (void) NXHashInsert (prototypes, proto);
 151         proto = NXHashGet (prototypes, &prototype);
 152         if (! proto) {
 153             _objc_syslog ("*** NXCreateHashTable: bug\n");
 154             return NULL;
 155             };
 156         };
 157     table->prototype = proto; table->count = 0; table->info = info;
 158     table->nbBuckets = exp2m1 (log2 (capacity)+1);
 159     table->buckets = ALLOCBUCKETS(z, table->nbBuckets);
 160     return table;
 161     }
 162
 163 static void freeBucketPairs (void (*freeProc)(const void *info, void *data), HashBucket bucket, const void *info) {
 164     unsigned    j = bucket.count;
 165     const void  **pairs;
 166
 167     if (j == 1) {
 168         (*freeProc) (info, (void *) bucket.elements.one);
 169         return;
 170         };
 171     pairs = bucket.elements.many;
 172     while (j--) {
 173         (*freeProc) (info, (void *) *pairs);
 174         pairs ++;
 175         };
 176     free (bucket.elements.many);
 177     };
 178
 179 static void freeBuckets (NXHashTable *table, int freeObjects) {
 180     unsigned            i = table->nbBuckets;
 181     HashBucket          *buckets = (HashBucket *) table->buckets;
 182
 183     while (i--) {
 184         if (buckets->count) {
 185             freeBucketPairs ((freeObjects) ? table->prototype->free : NXNoEffectFree, *buckets, table->info);
 186             buckets->count = 0;
 187             buckets->elements.one = NULL;
 188             };
 189         buckets++;
 190         };
 191     };
 192
 193 void NXFreeHashTable (NXHashTable *table) {
 194     freeBuckets (table, YES);
 195     free (table->buckets);
 196     free (table);
 197     };
 198
 199 void NXEmptyHashTable (NXHashTable *table) {
 200     freeBuckets (table, NO);
 201     table->count = 0;
 202     }
 203
 204 void NXResetHashTable (NXHashTable *table) {
 205     freeBuckets (table, YES);
 206     table->count = 0;
 207 }
 208
 209 BOOL NXIsEqualHashTable (NXHashTable *table1, NXHashTable *table2) {
 210     if (table1 == table2) return YES;
 211     if (NXCountHashTable (table1) != NXCountHashTable (table2)) return NO;
 212     else {
 213         void            *data;
 214         NXHashState     state = NXInitHashState (table1);
 215         while (NXNextHashState (table1, &state, &data)) {
 216             if (! NXHashMember (table2, data)) return NO;
 217         }
 218         return YES;
 219     }
 220 }
 221
 222 BOOL NXCompareHashTables (NXHashTable *table1, NXHashTable *table2) {
 223     if (table1 == table2) return YES;
 224     if (NXCountHashTable (table1) != NXCountHashTable (table2)) return NO;
 225     else {
 226         void            *data;
 227         NXHashState     state = NXInitHashState (table1);
 228         while (NXNextHashState (table1, &state, &data)) {
 229             if (! NXHashMember (table2, data)) return NO;
 230         }
 231         return YES;
 232     }
 233 }
 234
 235 NXHashTable *NXCopyHashTable (NXHashTable *table) {
 236     NXHashTable         *new;
 237     NXHashState         state = NXInitHashState (table);
 238     void                *data;
 239     void                *z = malloc_zone_from_ptr(table);
 240
 241     new = ALLOCTABLE(z);
 242     new->prototype = table->prototype; new->count = 0;
 243     new->info = table->info;
 244     new->nbBuckets = table->nbBuckets;
 245     new->buckets = ALLOCBUCKETS(z, new->nbBuckets);
 246     while (NXNextHashState (table, &state, &data))
 247         (void) NXHashInsert (new, data);
 248     return new;
 249     }
 250
 251 unsigned NXCountHashTable (NXHashTable *table) {
 252     return table->count;
 253     }
 254
 255 int NXHashMember (NXHashTable *table, const void *data) {
 256     HashBucket  *bucket = BUCKETOF(table, data);
 257     unsigned    j = bucket->count;
 258     const void  **pairs;
 259
 260     if (! j) return 0;
 261     if (j == 1) {
 262         return ISEQUAL(table, data, bucket->elements.one);
 263         };
 264     pairs = bucket->elements.many;
 265     while (j--) {
 266         /* we don't cache isEqual because lists are short */
 267         if (ISEQUAL(table, data, *pairs)) return 1;
 268         pairs ++;
 269         };
 270     return 0;
 271     }
 272
 273 void *NXHashGet (NXHashTable *table, const void *data) {
 274     HashBucket  *bucket = BUCKETOF(table, data);
 275     unsigned    j = bucket->count;
 276     const void  **pairs;
 277
 278     if (! j) return NULL;
 279     if (j == 1) {
 280         return ISEQUAL(table, data, bucket->elements.one)
 281             ? (void *) bucket->elements.one : NULL;
 282         };
 283     pairs = bucket->elements.many;
 284     while (j--) {
 285         /* we don't cache isEqual because lists are short */
 286         if (ISEQUAL(table, data, *pairs)) return (void *) *pairs;
 287         pairs ++;
 288         };
 289     return NULL;
 290     }
 291
 292 static void _NXHashRehash (NXHashTable *table) {
 293     /* Rehash: we create a pseudo table pointing really to the old guys,
 294     extend self, copy the old pairs, and free the pseudo table */
 295     NXHashTable *old;
 296     NXHashState state;
 297     void        *aux;
 298     void        *z = malloc_zone_from_ptr(table);
 299
 300     old = ALLOCTABLE(z);
 301     old->prototype = table->prototype; old->count = table->count;
 302     old->nbBuckets = table->nbBuckets; old->buckets = table->buckets;
 303     table->nbBuckets += table->nbBuckets + 1; /* 2 times + 1 */
 304     table->count = 0; table->buckets = ALLOCBUCKETS(z, table->nbBuckets);
 305     state = NXInitHashState (old);
 306     while (NXNextHashState (old, &state, &aux))
 307         (void) NXHashInsert (table, aux);
 308     freeBuckets (old, NO);
 309     if (old->count != table->count)
 310         _objc_syslog("*** hashtable: 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");
 311     free (old->buckets);
 312     free (old);
 313     };
 314
 315 void *NXHashInsert (NXHashTable *table, const void *data) {
 316     HashBucket  *bucket = BUCKETOF(table, data);
 317     unsigned    j = bucket->count;
 318     const void  **pairs;
 319     const void  **new;
 320     void        *z = malloc_zone_from_ptr(table);
 321
 322     if (! j) {
 323         bucket->count++; bucket->elements.one = data;
 324         table->count++;
 325         return NULL;
 326         };
 327     if (j == 1) {
 328         if (ISEQUAL(table, data, bucket->elements.one)) {
 329             const void  *old = bucket->elements.one;
 330             bucket->elements.one = data;
 331             return (void *) old;
 332             };
 333         new = ALLOCPAIRS(z, 2);
 334         new[1] = bucket->elements.one;
 335         *new = data;
 336         bucket->count++; bucket->elements.many = new;
 337         table->count++;
 338         if (table->count > table->nbBuckets) _NXHashRehash (table);
 339         return NULL;
 340         };
 341     pairs = bucket->elements.many;
 342     while (j--) {
 343         /* we don't cache isEqual because lists are short */
 344         if (ISEQUAL(table, data, *pairs)) {
 345             const void  *old = *pairs;
 346             *pairs = data;
 347             return (void *) old;
 348             };
 349         pairs ++;
 350         };
 351     /* we enlarge this bucket; and put new data in front */
 352     new = ALLOCPAIRS(z, bucket->count+1);
 353     if (bucket->count) bcopy ((const char*)bucket->elements.many, (char*)(new+1), bucket->count * PTRSIZE);
 354     *new = data;
 355     free (bucket->elements.many);
 356     bucket->count++; bucket->elements.many = new;
 357     table->count++;
 358     if (table->count > table->nbBuckets) _NXHashRehash (table);
 359     return NULL;
 360     }
 361
 362 void *NXHashInsertIfAbsent (NXHashTable *table, const void *data) {
 363     HashBucket  *bucket = BUCKETOF(table, data);
 364     unsigned    j = bucket->count;
 365     const void  **pairs;
 366     const void  **new;
 367     void        *z = malloc_zone_from_ptr(table);
 368
 369     if (! j) {
 370         bucket->count++; bucket->elements.one = data;
 371         table->count++;
 372         return (void *) data;
 373         };
 374     if (j == 1) {
 375         if (ISEQUAL(table, data, bucket->elements.one))
 376             return (void *) bucket->elements.one;
 377         new = ALLOCPAIRS(z, 2);
 378         new[1] = bucket->elements.one;
 379         *new = data;
 380         bucket->count++; bucket->elements.many = new;
 381         table->count++;
 382         if (table->count > table->nbBuckets) _NXHashRehash (table);
 383         return (void *) data;
 384         };
 385     pairs = bucket->elements.many;
 386     while (j--) {
 387         /* we don't cache isEqual because lists are short */
 388         if (ISEQUAL(table, data, *pairs))
 389             return (void *) *pairs;
 390         pairs ++;
 391         };
 392     /* we enlarge this bucket; and put new data in front */
 393     new = ALLOCPAIRS(z, bucket->count+1);
 394     if (bucket->count) bcopy ((const char*)bucket->elements.many, (char*)(new+1), bucket->count * PTRSIZE);
 395     *new = data;
 396     free (bucket->elements.many);
 397     bucket->count++; bucket->elements.many = new;
 398     table->count++;
 399     if (table->count > table->nbBuckets) _NXHashRehash (table);
 400     return (void *) data;
 401     }
 402
 403 void *NXHashRemove (NXHashTable *table, const void *data) {
 404     HashBucket  *bucket = BUCKETOF(table, data);
 405     unsigned    j = bucket->count;
 406     const void  **pairs;
 407     const void  **new;
 408     void        *z = malloc_zone_from_ptr(table);
 409
 410     if (! j) return NULL;
 411     if (j == 1) {
 412         if (! ISEQUAL(table, data, bucket->elements.one)) return NULL;
 413         data = bucket->elements.one;
 414         table->count--; bucket->count--; bucket->elements.one = NULL;
 415         return (void *) data;
 416         };
 417     pairs = bucket->elements.many;
 418     if (j == 2) {
 419         if (ISEQUAL(table, data, pairs[0])) {
 420             bucket->elements.one = pairs[1]; data = pairs[0];
 421             }
 422         else if (ISEQUAL(table, data, pairs[1])) {
 423             bucket->elements.one = pairs[0]; data = pairs[1];
 424             }
 425         else return NULL;
 426         free (pairs);
 427         table->count--; bucket->count--;
 428         return (void *) data;
 429         };
 430     while (j--) {
 431         if (ISEQUAL(table, data, *pairs)) {
 432             data = *pairs;
 433             /* we shrink this bucket */
 434             new = (bucket->count-1)
 435                 ? ALLOCPAIRS(z, bucket->count-1) : NULL;
 436             if (bucket->count-1 != j)
 437                     bcopy ((const char*)bucket->elements.many, (char*)new, PTRSIZE*(bucket->count-j-1));
 438             if (j)
 439                     bcopy ((const char*)(bucket->elements.many + bucket->count-j), (char*)(new+bucket->count-j-1), PTRSIZE*j);
 440             free (bucket->elements.many);
 441             table->count--; bucket->count--; bucket->elements.many = new;
 442             return (void *) data;
 443             };
 444         pairs ++;
 445         };
 446     return NULL;
 447     }
 448
 449 NXHashState NXInitHashState (NXHashTable *table) {
 450     NXHashState state;
 451
 452     state.i = table->nbBuckets;
 453     state.j = 0;
 454     return state;
 455     };
 456
 457 int NXNextHashState (NXHashTable *table, NXHashState *state, void **data) {
 458     HashBucket          *buckets = (HashBucket *) table->buckets;
 459
 460     while (state->j == 0) {
 461         if (state->i == 0) return NO;
 462         state->i--; state->j = buckets[state->i].count;
 463         }
 464     state->j--;
 465     buckets += state->i;
 466     *data = (void *) ((buckets->count == 1)
 467                 ? buckets->elements.one : buckets->elements.many[state->j]);
 468     return YES;
 469     };
 470
 471 /*************************************************************************
 472  *
 473  *      Conveniences
 474  *
 475  *************************************************************************/
 476
 477 uarith_t NXPtrHash (const void *info, const void *data) {
 478     return (((uarith_t) data) >> 16) ^ ((uarith_t) data);
 479     };
 480
 481 uarith_t NXStrHash (const void *info, const void *data) {
 482     register uarith_t   hash = 0;
 483     register unsigned char      *s = (unsigned char *) data;
 484     /* unsigned to avoid a sign-extend */
 485     /* unroll the loop */
 486     if (s) for (; ; ) {
 487         if (*s == '\0') break;
 488         hash ^= (uarith_t) *s++;
 489         if (*s == '\0') break;
 490         hash ^= (uarith_t) *s++ << 8;
 491         if (*s == '\0') break;
 492         hash ^= (uarith_t) *s++ << 16;
 493         if (*s == '\0') break;
 494         hash ^= (uarith_t) *s++ << 24;
 495         }
 496     return hash;
 497     };
 498
 499 int NXStrIsEqual (const void *info, const void *data1, const void *data2) {
 500     if (data1 == data2) return YES;
 501     if (! data1) return ! strlen ((char *) data2);
 502     if (! data2) return ! strlen ((char *) data1);
 503     if (((char *) data1)[0] != ((char *) data2)[0]) return NO;
 504     return (strcmp ((char *) data1, (char *) data2)) ? NO : YES;
 505     };
 506
 507 void NXReallyFree (const void *info, void *data) {
 508     free (data);
 509     };
 510
 511 /* All the following functions are really private, made non-static only for the benefit of shlibs */
 512 static uarith_t hashPtrStructKey (const void *info, const void *data) {
 513     return NXPtrHash(info, *((void **) data));
 514     };
 515
 516 static int isEqualPtrStructKey (const void *info, const void *data1, const void *data2) {
 517     return NXPtrIsEqual (info, *((void **) data1), *((void **) data2));
 518     };
 519
 520 static uarith_t hashStrStructKey (const void *info, const void *data) {
 521     return NXStrHash(info, *((char **) data));
 522     };
 523
 524 static int isEqualStrStructKey (const void *info, const void *data1, const void *data2) {
 525     return NXStrIsEqual (info, *((char **) data1), *((char **) data2));
 526     };
 527
 528 const NXHashTablePrototype NXPtrPrototype = {
 529     NXPtrHash, NXPtrIsEqual, NXNoEffectFree, 0
 530     };
 531
 532 const NXHashTablePrototype NXStrPrototype = {
 533     NXStrHash, NXStrIsEqual, NXNoEffectFree, 0
 534     };
 535
 536 const NXHashTablePrototype NXPtrStructKeyPrototype = {
 537     hashPtrStructKey, isEqualPtrStructKey, NXReallyFree, 0
 538     };
 539
 540 const NXHashTablePrototype NXStrStructKeyPrototype = {
 541     hashStrStructKey, isEqualStrStructKey, NXReallyFree, 0
 542     };
 543
 544 /*************************************************************************
 545  *
 546  *      Unique strings
 547  *
 548  *************************************************************************/
 549
 550 /* the implementation could be made faster at the expense of memory if the size of the strings were kept around */
 551 static NXHashTable *uniqueStrings = NULL;
 552
 553 /* this is based on most apps using a few K of strings, and an average string size of 15 using sqrt(2*dataAlloced*perChunkOverhead) */
 554 #define CHUNK_SIZE      360
 555
 556 static int accessUniqueString = 0;
 557
 558 static char             *z = NULL;
 559 static vm_size_t        zSize = 0;
 560 static mutex_t          lock = (mutex_t)0;
 561
 562 static const char *CopyIntoReadOnly (const char *str) {
 563     unsigned int        len = strlen (str) + 1;
 564     char        *new;
 565
 566     if (len > CHUNK_SIZE/2) {   /* dont let big strings waste space */
 567         new = malloc (len);
 568         bcopy (str, new, len);
 569         return new;
 570     }
 571
 572     if (! lock) {
 573         lock = (mutex_t)mutex_alloc ();
 574         mutex_init (lock);
 575         };
 576
 577     mutex_lock (lock);
 578     if (zSize < len) {
 579         zSize = CHUNK_SIZE *((len + CHUNK_SIZE - 1) / CHUNK_SIZE);
 580         /* not enough room, we try to allocate.  If no room left, too bad */
 581         z = malloc (zSize);
 582         };
 583
 584     new = z;
 585     bcopy (str, new, len);
 586     z += len;
 587     zSize -= len;
 588     mutex_unlock (lock);
 589     return new;
 590     };
 591
 592 NXAtom NXUniqueString (const char *buffer) {
 593     const char  *previous;
 594
 595     if (! buffer) return buffer;
 596     accessUniqueString++;
 597     if (! uniqueStrings)
 598         uniqueStrings = NXCreateHashTable (NXStrPrototype, 0, NULL);
 599     previous = (const char *) NXHashGet (uniqueStrings, buffer);
 600     if (previous) return previous;
 601     previous = CopyIntoReadOnly (buffer);
 602     if (NXHashInsert (uniqueStrings, previous)) {
 603         _objc_syslog ("*** NXUniqueString: invariant broken\n");
 604         return NULL;
 605         };
 606     return previous;
 607     };
 608
 609 NXAtom NXUniqueStringNoCopy (const char *string) {
 610     accessUniqueString++;
 611     if (! uniqueStrings)
 612         uniqueStrings = NXCreateHashTable (NXStrPrototype, 0, NULL);
 613     return (const char *) NXHashInsertIfAbsent (uniqueStrings, string);
 614     };
 615
 616 #define BUF_SIZE        256
 617
 618 NXAtom NXUniqueStringWithLength (const char *buffer, int length) {
 619     NXAtom      atom;
 620     char        *nullTermStr;
 621     char        stackBuf[BUF_SIZE];
 622
 623     if (length+1 > BUF_SIZE)
 624         nullTermStr = malloc (length+1);
 625     else
 626         nullTermStr = stackBuf;
 627     bcopy (buffer, nullTermStr, length);
 628     nullTermStr[length] = '\0';
 629     atom = NXUniqueString (nullTermStr);
 630     if (length+1 > BUF_SIZE)
 631         free (nullTermStr);
 632     return atom;
 633     };
 634
 635 char *NXCopyStringBufferFromZone (const char *str, void *z) {
 636     return strcpy ((char *) malloc_zone_malloc(z, strlen (str) + 1), str);
 637     };
 638
 639 char *NXCopyStringBuffer (const char *str) {
 640     return NXCopyStringBufferFromZone(str, malloc_default_zone());
 641     };
 642