File: linkhash.c

package info (click to toggle)
json-c 0.15-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 2,496 kB
  • sloc: ansic: 8,165; sh: 493; javascript: 82; makefile: 12; cpp: 11
file content (716 lines) | stat: -rw-r--r-- 21,274 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
/*
 * $Id: linkhash.c,v 1.4 2006/01/26 02:16:28 mclark Exp $
 *
 * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
 * Michael Clark <michael@metaparadigm.com>
 * Copyright (c) 2009 Hewlett-Packard Development Company, L.P.
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See COPYING for details.
 *
 */

#include "config.h"

#include <assert.h>
#include <limits.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef HAVE_ENDIAN_H
#include <endian.h> /* attempt to define endianness */
#endif

#if defined(_MSC_VER) || defined(__MINGW32__)
#define WIN32_LEAN_AND_MEAN
#include <windows.h> /* Get InterlockedCompareExchange */
#endif

#include "linkhash.h"
#include "random_seed.h"

/* hash functions */
static unsigned long lh_char_hash(const void *k);
static unsigned long lh_perllike_str_hash(const void *k);
static lh_hash_fn *char_hash_fn = lh_char_hash;

/* comparison functions */
int lh_char_equal(const void *k1, const void *k2);
int lh_ptr_equal(const void *k1, const void *k2);

int json_global_set_string_hash(const int h)
{
	switch (h)
	{
	case JSON_C_STR_HASH_DFLT: char_hash_fn = lh_char_hash; break;
	case JSON_C_STR_HASH_PERLLIKE: char_hash_fn = lh_perllike_str_hash; break;
	default: return -1;
	}
	return 0;
}

static unsigned long lh_ptr_hash(const void *k)
{
	/* CAW: refactored to be 64bit nice */
	return (unsigned long)((((ptrdiff_t)k * LH_PRIME) >> 4) & ULONG_MAX);
}

int lh_ptr_equal(const void *k1, const void *k2)
{
	return (k1 == k2);
}

/*
 * hashlittle from lookup3.c, by Bob Jenkins, May 2006, Public Domain.
 * http://burtleburtle.net/bob/c/lookup3.c
 * minor modifications to make functions static so no symbols are exported
 * minor mofifications to compile with -Werror
 */

/*
-------------------------------------------------------------------------------
lookup3.c, by Bob Jenkins, May 2006, Public Domain.

These are functions for producing 32-bit hashes for hash table lookup.
hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
are externally useful functions.  Routines to test the hash are included
if SELF_TEST is defined.  You can use this free for any purpose.  It's in
the public domain.  It has no warranty.

You probably want to use hashlittle().  hashlittle() and hashbig()
hash byte arrays.  hashlittle() is is faster than hashbig() on
little-endian machines.  Intel and AMD are little-endian machines.
On second thought, you probably want hashlittle2(), which is identical to
hashlittle() except it returns two 32-bit hashes for the price of one.
You could implement hashbig2() if you wanted but I haven't bothered here.

If you want to find a hash of, say, exactly 7 integers, do
  a = i1;  b = i2;  c = i3;
  mix(a,b,c);
  a += i4; b += i5; c += i6;
  mix(a,b,c);
  a += i7;
  final(a,b,c);
then use c as the hash value.  If you have a variable length array of
4-byte integers to hash, use hashword().  If you have a byte array (like
a character string), use hashlittle().  If you have several byte arrays, or
a mix of things, see the comments above hashlittle().

Why is this so big?  I read 12 bytes at a time into 3 4-byte integers,
then mix those integers.  This is fast (you can do a lot more thorough
mixing with 12*3 instructions on 3 integers than you can with 3 instructions
on 1 byte), but shoehorning those bytes into integers efficiently is messy.
-------------------------------------------------------------------------------
*/

/*
 * My best guess at if you are big-endian or little-endian.  This may
 * need adjustment.
 */
#if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && __BYTE_ORDER == __LITTLE_ENDIAN) || \
    (defined(i386) || defined(__i386__) || defined(__i486__) || defined(__i586__) ||          \
     defined(__i686__) || defined(vax) || defined(MIPSEL))
#define HASH_LITTLE_ENDIAN 1
#define HASH_BIG_ENDIAN 0
#elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && __BYTE_ORDER == __BIG_ENDIAN) || \
    (defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel))
#define HASH_LITTLE_ENDIAN 0
#define HASH_BIG_ENDIAN 1
#else
#define HASH_LITTLE_ENDIAN 0
#define HASH_BIG_ENDIAN 0
#endif

#define hashsize(n) ((uint32_t)1 << (n))
#define hashmask(n) (hashsize(n) - 1)
#define rot(x, k) (((x) << (k)) | ((x) >> (32 - (k))))

/*
-------------------------------------------------------------------------------
mix -- mix 3 32-bit values reversibly.

This is reversible, so any information in (a,b,c) before mix() is
still in (a,b,c) after mix().

If four pairs of (a,b,c) inputs are run through mix(), or through
mix() in reverse, there are at least 32 bits of the output that
are sometimes the same for one pair and different for another pair.
This was tested for:
* pairs that differed by one bit, by two bits, in any combination
  of top bits of (a,b,c), or in any combination of bottom bits of
  (a,b,c).
* "differ" is defined as +, -, ^, or ~^.  For + and -, I transformed
  the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
  is commonly produced by subtraction) look like a single 1-bit
  difference.
* the base values were pseudorandom, all zero but one bit set, or
  all zero plus a counter that starts at zero.

Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
satisfy this are
    4  6  8 16 19  4
    9 15  3 18 27 15
   14  9  3  7 17  3
Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
for "differ" defined as + with a one-bit base and a two-bit delta.  I
used http://burtleburtle.net/bob/hash/avalanche.html to choose
the operations, constants, and arrangements of the variables.

This does not achieve avalanche.  There are input bits of (a,b,c)
that fail to affect some output bits of (a,b,c), especially of a.  The
most thoroughly mixed value is c, but it doesn't really even achieve
avalanche in c.

This allows some parallelism.  Read-after-writes are good at doubling
the number of bits affected, so the goal of mixing pulls in the opposite
direction as the goal of parallelism.  I did what I could.  Rotates
seem to cost as much as shifts on every machine I could lay my hands
on, and rotates are much kinder to the top and bottom bits, so I used
rotates.
-------------------------------------------------------------------------------
*/
/* clang-format off */
#define mix(a,b,c) \
{ \
	a -= c;  a ^= rot(c, 4);  c += b; \
	b -= a;  b ^= rot(a, 6);  a += c; \
	c -= b;  c ^= rot(b, 8);  b += a; \
	a -= c;  a ^= rot(c,16);  c += b; \
	b -= a;  b ^= rot(a,19);  a += c; \
	c -= b;  c ^= rot(b, 4);  b += a; \
}
/* clang-format on */

/*
-------------------------------------------------------------------------------
final -- final mixing of 3 32-bit values (a,b,c) into c

Pairs of (a,b,c) values differing in only a few bits will usually
produce values of c that look totally different.  This was tested for
* pairs that differed by one bit, by two bits, in any combination
  of top bits of (a,b,c), or in any combination of bottom bits of
  (a,b,c).
* "differ" is defined as +, -, ^, or ~^.  For + and -, I transformed
  the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
  is commonly produced by subtraction) look like a single 1-bit
  difference.
* the base values were pseudorandom, all zero but one bit set, or
  all zero plus a counter that starts at zero.

These constants passed:
 14 11 25 16 4 14 24
 12 14 25 16 4 14 24
and these came close:
  4  8 15 26 3 22 24
 10  8 15 26 3 22 24
 11  8 15 26 3 22 24
-------------------------------------------------------------------------------
*/
/* clang-format off */
#define final(a,b,c) \
{ \
	c ^= b; c -= rot(b,14); \
	a ^= c; a -= rot(c,11); \
	b ^= a; b -= rot(a,25); \
	c ^= b; c -= rot(b,16); \
	a ^= c; a -= rot(c,4);  \
	b ^= a; b -= rot(a,14); \
	c ^= b; c -= rot(b,24); \
}
/* clang-format on */

/*
-------------------------------------------------------------------------------
hashlittle() -- hash a variable-length key into a 32-bit value
  k       : the key (the unaligned variable-length array of bytes)
  length  : the length of the key, counting by bytes
  initval : can be any 4-byte value
Returns a 32-bit value.  Every bit of the key affects every bit of
the return value.  Two keys differing by one or two bits will have
totally different hash values.

The best hash table sizes are powers of 2.  There is no need to do
mod a prime (mod is sooo slow!).  If you need less than 32 bits,
use a bitmask.  For example, if you need only 10 bits, do
  h = (h & hashmask(10));
In which case, the hash table should have hashsize(10) elements.

If you are hashing n strings (uint8_t **)k, do it like this:
  for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h);

By Bob Jenkins, 2006.  bob_jenkins@burtleburtle.net.  You may use this
code any way you wish, private, educational, or commercial.  It's free.

Use for hash table lookup, or anything where one collision in 2^^32 is
acceptable.  Do NOT use for cryptographic purposes.
-------------------------------------------------------------------------------
*/

/* clang-format off */
static uint32_t hashlittle(const void *key, size_t length, uint32_t initval)
{
	uint32_t a,b,c; /* internal state */
	union
	{
		const void *ptr;
		size_t i;
	} u; /* needed for Mac Powerbook G4 */

	/* Set up the internal state */
	a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;

	u.ptr = key;
	if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
		const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */

		/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			b += k[1];
			c += k[2];
			mix(a,b,c);
			length -= 12;
			k += 3;
		}

		/*----------------------------- handle the last (probably partial) block */
		/*
		 * "k[2]&0xffffff" actually reads beyond the end of the string, but
		 * then masks off the part it's not allowed to read.  Because the
		 * string is aligned, the masked-off tail is in the same word as the
		 * rest of the string.  Every machine with memory protection I've seen
		 * does it on word boundaries, so is OK with this.  But VALGRIND will
		 * still catch it and complain.  The masking trick does make the hash
		 * noticably faster for short strings (like English words).
		 * AddressSanitizer is similarly picky about overrunning
		 * the buffer. (http://clang.llvm.org/docs/AddressSanitizer.html
		 */
#ifdef VALGRIND
#define PRECISE_MEMORY_ACCESS 1
#elif defined(__SANITIZE_ADDRESS__) /* GCC's ASAN */
#define PRECISE_MEMORY_ACCESS 1
#elif defined(__has_feature)
#if __has_feature(address_sanitizer) /* Clang's ASAN */
#define PRECISE_MEMORY_ACCESS 1
#endif
#endif
#ifndef PRECISE_MEMORY_ACCESS

		switch(length)
		{
		case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
		case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
		case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
		case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
		case 8 : b+=k[1]; a+=k[0]; break;
		case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
		case 6 : b+=k[1]&0xffff; a+=k[0]; break;
		case 5 : b+=k[1]&0xff; a+=k[0]; break;
		case 4 : a+=k[0]; break;
		case 3 : a+=k[0]&0xffffff; break;
		case 2 : a+=k[0]&0xffff; break;
		case 1 : a+=k[0]&0xff; break;
		case 0 : return c; /* zero length strings require no mixing */
		}

#else /* make valgrind happy */

		const uint8_t  *k8 = (const uint8_t *)k;
		switch(length)
		{
		case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
		case 11: c+=((uint32_t)k8[10])<<16;  /* fall through */
		case 10: c+=((uint32_t)k8[9])<<8;    /* fall through */
		case 9 : c+=k8[8];                   /* fall through */
		case 8 : b+=k[1]; a+=k[0]; break;
		case 7 : b+=((uint32_t)k8[6])<<16;   /* fall through */
		case 6 : b+=((uint32_t)k8[5])<<8;    /* fall through */
		case 5 : b+=k8[4];                   /* fall through */
		case 4 : a+=k[0]; break;
		case 3 : a+=((uint32_t)k8[2])<<16;   /* fall through */
		case 2 : a+=((uint32_t)k8[1])<<8;    /* fall through */
		case 1 : a+=k8[0]; break;
		case 0 : return c;
		}

#endif /* !valgrind */

	}
	else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0))
	{
		const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
		const uint8_t  *k8;

		/*--------------- all but last block: aligned reads and different mixing */
		while (length > 12)
		{
			a += k[0] + (((uint32_t)k[1])<<16);
			b += k[2] + (((uint32_t)k[3])<<16);
			c += k[4] + (((uint32_t)k[5])<<16);
			mix(a,b,c);
			length -= 12;
			k += 6;
		}

		/*----------------------------- handle the last (probably partial) block */
		k8 = (const uint8_t *)k;
		switch(length)
		{
		case 12: c+=k[4]+(((uint32_t)k[5])<<16);
			 b+=k[2]+(((uint32_t)k[3])<<16);
			 a+=k[0]+(((uint32_t)k[1])<<16);
			 break;
		case 11: c+=((uint32_t)k8[10])<<16;     /* fall through */
		case 10: c+=k[4];
			 b+=k[2]+(((uint32_t)k[3])<<16);
			 a+=k[0]+(((uint32_t)k[1])<<16);
			 break;
		case 9 : c+=k8[8];                      /* fall through */
		case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
			 a+=k[0]+(((uint32_t)k[1])<<16);
			 break;
		case 7 : b+=((uint32_t)k8[6])<<16;      /* fall through */
		case 6 : b+=k[2];
			 a+=k[0]+(((uint32_t)k[1])<<16);
			 break;
		case 5 : b+=k8[4];                      /* fall through */
		case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
			 break;
		case 3 : a+=((uint32_t)k8[2])<<16;      /* fall through */
		case 2 : a+=k[0];
			 break;
		case 1 : a+=k8[0];
			 break;
		case 0 : return c;                     /* zero length requires no mixing */
		}

	}
	else
	{
		/* need to read the key one byte at a time */
		const uint8_t *k = (const uint8_t *)key;

		/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			a += ((uint32_t)k[1])<<8;
			a += ((uint32_t)k[2])<<16;
			a += ((uint32_t)k[3])<<24;
			b += k[4];
			b += ((uint32_t)k[5])<<8;
			b += ((uint32_t)k[6])<<16;
			b += ((uint32_t)k[7])<<24;
			c += k[8];
			c += ((uint32_t)k[9])<<8;
			c += ((uint32_t)k[10])<<16;
			c += ((uint32_t)k[11])<<24;
			mix(a,b,c);
			length -= 12;
			k += 12;
		}

		/*-------------------------------- last block: affect all 32 bits of (c) */
		switch(length) /* all the case statements fall through */
		{
		case 12: c+=((uint32_t)k[11])<<24; /* FALLTHRU */
		case 11: c+=((uint32_t)k[10])<<16; /* FALLTHRU */
		case 10: c+=((uint32_t)k[9])<<8; /* FALLTHRU */
		case 9 : c+=k[8]; /* FALLTHRU */
		case 8 : b+=((uint32_t)k[7])<<24; /* FALLTHRU */
		case 7 : b+=((uint32_t)k[6])<<16; /* FALLTHRU */
		case 6 : b+=((uint32_t)k[5])<<8; /* FALLTHRU */
		case 5 : b+=k[4]; /* FALLTHRU */
		case 4 : a+=((uint32_t)k[3])<<24; /* FALLTHRU */
		case 3 : a+=((uint32_t)k[2])<<16; /* FALLTHRU */
		case 2 : a+=((uint32_t)k[1])<<8; /* FALLTHRU */
		case 1 : a+=k[0];
			 break;
		case 0 : return c;
		}
	}

	final(a,b,c);
	return c;
}
/* clang-format on */

/* a simple hash function similiar to what perl does for strings.
 * for good results, the string should not be excessivly large.
 */
static unsigned long lh_perllike_str_hash(const void *k)
{
	const char *rkey = (const char *)k;
	unsigned hashval = 1;

	while (*rkey)
		hashval = hashval * 33 + *rkey++;

	return hashval;
}

static unsigned long lh_char_hash(const void *k)
{
#if defined _MSC_VER || defined __MINGW32__
#define RANDOM_SEED_TYPE LONG
#else
#define RANDOM_SEED_TYPE int
#endif
	static volatile RANDOM_SEED_TYPE random_seed = -1;

	if (random_seed == -1)
	{
		RANDOM_SEED_TYPE seed;
		/* we can't use -1 as it is the unitialized sentinel */
		while ((seed = json_c_get_random_seed()) == -1) {}
#if SIZEOF_INT == 8 && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
#define USE_SYNC_COMPARE_AND_SWAP 1
#endif
#if SIZEOF_INT == 4 && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
#define USE_SYNC_COMPARE_AND_SWAP 1
#endif
#if SIZEOF_INT == 2 && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2
#define USE_SYNC_COMPARE_AND_SWAP 1
#endif
#if defined USE_SYNC_COMPARE_AND_SWAP
		(void)__sync_val_compare_and_swap(&random_seed, -1, seed);
#elif defined _MSC_VER || defined __MINGW32__
		InterlockedCompareExchange(&random_seed, seed, -1);
#else
		//#warning "racy random seed initializtion if used by multiple threads"
		random_seed = seed; /* potentially racy */
#endif
	}

	return hashlittle((const char *)k, strlen((const char *)k), random_seed);
}

int lh_char_equal(const void *k1, const void *k2)
{
	return (strcmp((const char *)k1, (const char *)k2) == 0);
}

struct lh_table *lh_table_new(int size, lh_entry_free_fn *free_fn, lh_hash_fn *hash_fn,
                              lh_equal_fn *equal_fn)
{
	int i;
	struct lh_table *t;

	/* Allocate space for elements to avoid divisions by zero. */
	assert(size > 0);
	t = (struct lh_table *)calloc(1, sizeof(struct lh_table));
	if (!t)
		return NULL;

	t->count = 0;
	t->size = size;
	t->table = (struct lh_entry *)calloc(size, sizeof(struct lh_entry));
	if (!t->table)
	{
		free(t);
		return NULL;
	}
	t->free_fn = free_fn;
	t->hash_fn = hash_fn;
	t->equal_fn = equal_fn;
	for (i = 0; i < size; i++)
		t->table[i].k = LH_EMPTY;
	return t;
}

struct lh_table *lh_kchar_table_new(int size, lh_entry_free_fn *free_fn)
{
	return lh_table_new(size, free_fn, char_hash_fn, lh_char_equal);
}

struct lh_table *lh_kptr_table_new(int size, lh_entry_free_fn *free_fn)
{
	return lh_table_new(size, free_fn, lh_ptr_hash, lh_ptr_equal);
}

int lh_table_resize(struct lh_table *t, int new_size)
{
	struct lh_table *new_t;
	struct lh_entry *ent;

	new_t = lh_table_new(new_size, NULL, t->hash_fn, t->equal_fn);
	if (new_t == NULL)
		return -1;

	for (ent = t->head; ent != NULL; ent = ent->next)
	{
		unsigned long h = lh_get_hash(new_t, ent->k);
		unsigned int opts = 0;
		if (ent->k_is_constant)
			opts = JSON_C_OBJECT_KEY_IS_CONSTANT;
		if (lh_table_insert_w_hash(new_t, ent->k, ent->v, h, opts) != 0)
		{
			lh_table_free(new_t);
			return -1;
		}
	}
	free(t->table);
	t->table = new_t->table;
	t->size = new_size;
	t->head = new_t->head;
	t->tail = new_t->tail;
	free(new_t);

	return 0;
}

void lh_table_free(struct lh_table *t)
{
	struct lh_entry *c;
	if (t->free_fn)
	{
		for (c = t->head; c != NULL; c = c->next)
			t->free_fn(c);
	}
	free(t->table);
	free(t);
}

int lh_table_insert_w_hash(struct lh_table *t, const void *k, const void *v, const unsigned long h,
                           const unsigned opts)
{
	unsigned long n;

	if (t->count >= t->size * LH_LOAD_FACTOR)
	{
		/* Avoid signed integer overflow with large tables. */
		int new_size = (t->size > INT_MAX / 2) ? INT_MAX : (t->size * 2);
		if (t->size == INT_MAX || lh_table_resize(t, new_size) != 0)
			return -1;
	}

	n = h % t->size;

	while (1)
	{
		if (t->table[n].k == LH_EMPTY || t->table[n].k == LH_FREED)
			break;
		if ((int)++n == t->size)
			n = 0;
	}

	t->table[n].k = k;
	t->table[n].k_is_constant = (opts & JSON_C_OBJECT_KEY_IS_CONSTANT);
	t->table[n].v = v;
	t->count++;

	if (t->head == NULL)
	{
		t->head = t->tail = &t->table[n];
		t->table[n].next = t->table[n].prev = NULL;
	}
	else
	{
		t->tail->next = &t->table[n];
		t->table[n].prev = t->tail;
		t->table[n].next = NULL;
		t->tail = &t->table[n];
	}

	return 0;
}
int lh_table_insert(struct lh_table *t, const void *k, const void *v)
{
	return lh_table_insert_w_hash(t, k, v, lh_get_hash(t, k), 0);
}

struct lh_entry *lh_table_lookup_entry_w_hash(struct lh_table *t, const void *k,
                                              const unsigned long h)
{
	unsigned long n = h % t->size;
	int count = 0;

	while (count < t->size)
	{
		if (t->table[n].k == LH_EMPTY)
			return NULL;
		if (t->table[n].k != LH_FREED && t->equal_fn(t->table[n].k, k))
			return &t->table[n];
		if ((int)++n == t->size)
			n = 0;
		count++;
	}
	return NULL;
}

struct lh_entry *lh_table_lookup_entry(struct lh_table *t, const void *k)
{
	return lh_table_lookup_entry_w_hash(t, k, lh_get_hash(t, k));
}

json_bool lh_table_lookup_ex(struct lh_table *t, const void *k, void **v)
{
	struct lh_entry *e = lh_table_lookup_entry(t, k);
	if (e != NULL)
	{
		if (v != NULL)
			*v = lh_entry_v(e);
		return 1; /* key found */
	}
	if (v != NULL)
		*v = NULL;
	return 0; /* key not found */
}

int lh_table_delete_entry(struct lh_table *t, struct lh_entry *e)
{
	/* CAW: fixed to be 64bit nice, still need the crazy negative case... */
	ptrdiff_t n = (ptrdiff_t)(e - t->table);

	/* CAW: this is bad, really bad, maybe stack goes other direction on this machine... */
	if (n < 0)
	{
		return -2;
	}

	if (t->table[n].k == LH_EMPTY || t->table[n].k == LH_FREED)
		return -1;
	t->count--;
	if (t->free_fn)
		t->free_fn(e);
	t->table[n].v = NULL;
	t->table[n].k = LH_FREED;
	if (t->tail == &t->table[n] && t->head == &t->table[n])
	{
		t->head = t->tail = NULL;
	}
	else if (t->head == &t->table[n])
	{
		t->head->next->prev = NULL;
		t->head = t->head->next;
	}
	else if (t->tail == &t->table[n])
	{
		t->tail->prev->next = NULL;
		t->tail = t->tail->prev;
	}
	else
	{
		t->table[n].prev->next = t->table[n].next;
		t->table[n].next->prev = t->table[n].prev;
	}
	t->table[n].next = t->table[n].prev = NULL;
	return 0;
}

int lh_table_delete(struct lh_table *t, const void *k)
{
	struct lh_entry *e = lh_table_lookup_entry(t, k);
	if (!e)
		return -1;
	return lh_table_delete_entry(t, e);
}

int lh_table_length(struct lh_table *t)
{
	return t->count;
}