summaryrefslogtreecommitdiffstats
path: root/extra/mariabackup/quicklz/quicklz.c
blob: 3742129023a7a42d2128897e618e23da9fe13a2b (plain)
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
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
// Fast data compression library
// Copyright (C) 2006-2011 Lasse Mikkel Reinhold
// lar@quicklz.com
//
// QuickLZ can be used for free under the GPL 1, 2 or 3 license (where anything 
// released into public must be open source) or under a commercial license if such 
// has been acquired (see http://www.quicklz.com/order.html). The commercial license 
// does not cover derived or ported versions created by third parties under GPL.

// 1.5.0 final

#include "quicklz.h"

#if QLZ_VERSION_MAJOR != 1 || QLZ_VERSION_MINOR != 5 || QLZ_VERSION_REVISION != 0
	#error quicklz.c and quicklz.h have different versions
#endif

#if (defined(__X86__) || defined(__i386__) || defined(i386) || defined(_M_IX86) || defined(__386__) || defined(__x86_64__) || defined(_M_X64))
	#define X86X64
#endif

#define MINOFFSET 2
#define UNCONDITIONAL_MATCHLEN 6
#define UNCOMPRESSED_END 4
#define CWORD_LEN 4

#if QLZ_COMPRESSION_LEVEL == 1 && defined QLZ_PTR_64 && QLZ_STREAMING_BUFFER == 0
	#define OFFSET_BASE source
	#define CAST (ui32)(size_t)
#else
	#define OFFSET_BASE 0
	#define CAST
#endif

int qlz_get_setting(int setting)
{
	switch (setting)
	{
		case 0: return QLZ_COMPRESSION_LEVEL;
		case 1: return sizeof(qlz_state_compress);
		case 2: return sizeof(qlz_state_decompress);
		case 3: return QLZ_STREAMING_BUFFER;
#ifdef QLZ_MEMORY_SAFE
		case 6: return 1;
#else
		case 6: return 0;
#endif
		case 7: return QLZ_VERSION_MAJOR;
		case 8: return QLZ_VERSION_MINOR;
		case 9: return QLZ_VERSION_REVISION;
	}
	return -1;
}

#if QLZ_COMPRESSION_LEVEL == 1
static int same(const unsigned char *src, size_t n)
{
	while(n > 0 && *(src + n) == *src)
		n--;
	return n == 0 ? 1 : 0;
}
#endif

static void reset_table_compress(qlz_state_compress *state)
{
	int i;
	for(i = 0; i < QLZ_HASH_VALUES; i++)
	{
#if QLZ_COMPRESSION_LEVEL == 1
		state->hash[i].offset = 0;
#else
		state->hash_counter[i] = 0;
#endif
	}
}

static void reset_table_decompress(qlz_state_decompress *state)
{
	int i;
	(void)state;
	(void)i;
#if QLZ_COMPRESSION_LEVEL == 2
	for(i = 0; i < QLZ_HASH_VALUES; i++)
	{
		state->hash_counter[i] = 0;
	}
#endif
}

static __inline ui32 hash_func(ui32 i)
{
#if QLZ_COMPRESSION_LEVEL == 2
	return ((i >> 9) ^ (i >> 13) ^ i) & (QLZ_HASH_VALUES - 1);
#else
	return ((i >> 12) ^ i) & (QLZ_HASH_VALUES - 1);
#endif
}

static __inline ui32 fast_read(void const *src, ui32 bytes)
{
#ifndef X86X64
	unsigned char *p = (unsigned char*)src;
	switch (bytes)
	{
		case 4:
			return(*p | *(p + 1) << 8 | *(p + 2) << 16 | *(p + 3) << 24);
		case 3: 
			return(*p | *(p + 1) << 8 | *(p + 2) << 16);
		case 2:
			return(*p | *(p + 1) << 8);
		case 1: 
			return(*p);
	}
	return 0;
#else
	if (bytes >= 1 && bytes <= 4)
		return *((ui32*)src);
	else
		return 0;
#endif
}

static __inline ui32 hashat(const unsigned char *src)
{
	ui32 fetch, hash;
	fetch = fast_read(src, 3);
	hash = hash_func(fetch);
	return hash;
}

static __inline void fast_write(ui32 f, void *dst, size_t bytes)
{
#ifndef X86X64
	unsigned char *p = (unsigned char*)dst;

	switch (bytes)
	{
		case 4: 
			*p = (unsigned char)f;
			*(p + 1) = (unsigned char)(f >> 8);
			*(p + 2) = (unsigned char)(f >> 16);
			*(p + 3) = (unsigned char)(f >> 24);
			return;
		case 3:
			*p = (unsigned char)f;
			*(p + 1) = (unsigned char)(f >> 8);
			*(p + 2) = (unsigned char)(f >> 16);
			return;
		case 2:
			*p = (unsigned char)f;
			*(p + 1) = (unsigned char)(f >> 8);
			return;
		case 1:
			*p = (unsigned char)f;
			return;
	}
#else
	switch (bytes)
	{
		case 4: 
			*((ui32*)dst) = f;
			return;
		case 3:
			*((ui32*)dst) = f;
			return;
		case 2:
			*((ui16 *)dst) = (ui16)f;
			return;
		case 1:
			*((unsigned char*)dst) = (unsigned char)f;
			return;
	}
#endif
}


size_t qlz_size_decompressed(const char *source)
{
	ui32 n, r;
	n = (((*source) & 2) == 2) ? 4 : 1;
	r = fast_read(source + 1 + n, n);
	r = r & (0xffffffff >> ((4 - n)*8));
	return r;
}

size_t qlz_size_compressed(const char *source)
{
	ui32 n, r;
	n = (((*source) & 2) == 2) ? 4 : 1;
	r = fast_read(source + 1, n);
	r = r & (0xffffffff >> ((4 - n)*8));
	return r;
}

size_t qlz_size_header(const char *source)
{
	size_t n = 2*((((*source) & 2) == 2) ? 4 : 1) + 1;
	return n;
}


static __inline void memcpy_up(unsigned char *dst, const unsigned char *src, ui32 n)
{
	// Caution if modifying memcpy_up! Overlap of dst and src must be special handled.
#ifndef X86X64
	unsigned char *end = dst + n;
	while(dst < end)
	{
		*dst = *src;
		dst++;
		src++;
	}
#else
	ui32 f = 0;
	do
	{
		*(ui32 *)(dst + f) = *(ui32 *)(src + f);
		f += MINOFFSET + 1;
	}
	while (f < n);
#endif
}

static __inline void update_hash(qlz_state_decompress *state, const unsigned char *s)
{
#if QLZ_COMPRESSION_LEVEL == 1
	ui32 hash;
	hash = hashat(s);
	state->hash[hash].offset = s;
	state->hash_counter[hash] = 1;
#elif QLZ_COMPRESSION_LEVEL == 2
	ui32 hash;
	unsigned char c;
	hash = hashat(s);
	c = state->hash_counter[hash];
	state->hash[hash].offset[c & (QLZ_POINTERS - 1)] = s;
	c++;
	state->hash_counter[hash] = c;
#endif
	(void)state;
	(void)s;
}

#if QLZ_COMPRESSION_LEVEL <= 2
static void update_hash_upto(qlz_state_decompress *state, unsigned char **lh, const unsigned char *max)
{
	while(*lh < max)
	{
		(*lh)++;
		update_hash(state, *lh);
	}
}
#endif

static size_t qlz_compress_core(const unsigned char *source, unsigned char *destination, size_t size, qlz_state_compress *state)
{
	const unsigned char *last_byte = source + size - 1;
	const unsigned char *src = source;
	unsigned char *cword_ptr = destination;
	unsigned char *dst = destination + CWORD_LEN;
	ui32 cword_val = 1U << 31;
	const unsigned char *last_matchstart = last_byte - UNCONDITIONAL_MATCHLEN - UNCOMPRESSED_END; 
	ui32 fetch = 0;
	unsigned int lits = 0;

	(void) lits;

	if(src <= last_matchstart)
		fetch = fast_read(src, 3);
	
	while(src <= last_matchstart)
	{
		if ((cword_val & 1) == 1)
		{
			// store uncompressed if compression ratio is too low
			if (src > source + (size >> 1) && dst - destination > src - source - ((src - source) >> 5))
				return 0;

			fast_write((cword_val >> 1) | (1U << 31), cword_ptr, CWORD_LEN);

			cword_ptr = dst;
			dst += CWORD_LEN;
			cword_val = 1U << 31;
			fetch = fast_read(src, 3);
		}
#if QLZ_COMPRESSION_LEVEL == 1
		{
			const unsigned char *o;
			ui32 hash, cached;

			hash = hash_func(fetch);
			cached = fetch ^ state->hash[hash].cache;
			state->hash[hash].cache = fetch;

			o = state->hash[hash].offset + OFFSET_BASE;
			state->hash[hash].offset = CAST(src - OFFSET_BASE);

#ifdef X86X64
			if ((cached & 0xffffff) == 0 && o != OFFSET_BASE && (src - o > MINOFFSET || (src == o + 1 && lits >= 3 && src > source + 3 && same(src - 3, 6))))
			{
				if(cached != 0)
				{
#else
			if (cached == 0 && o != OFFSET_BASE && (src - o > MINOFFSET || (src == o + 1 && lits >= 3 && src > source + 3 && same(src - 3, 6))))
			{
				if (*(o + 3) != *(src + 3))
				{
#endif
					hash <<= 4;
					cword_val = (cword_val >> 1) | (1U << 31);
					fast_write((3 - 2) | hash, dst, 2);
					src += 3;
					dst += 2;
				}
				else
				{
					const unsigned char *old_src = src;
					size_t matchlen;
					hash <<= 4;

					cword_val = (cword_val >> 1) | (1U << 31);
					src += 4;

					if(*(o + (src - old_src)) == *src)
					{
						src++;
						if(*(o + (src - old_src)) == *src)
						{
							size_t q = last_byte - UNCOMPRESSED_END - (src - 5) + 1;
							size_t remaining = q > 255 ? 255 : q;
							src++;	
							while(*(o + (src - old_src)) == *src && (size_t)(src - old_src) < remaining)
								src++;
						}
					}

					matchlen = src - old_src;
					if (matchlen < 18)
					{
						fast_write((ui32)(matchlen - 2) | hash, dst, 2);
						dst += 2;
					} 
					else
					{
						fast_write((ui32)(matchlen << 16) | hash, dst, 3);
						dst += 3;
					}
				}
				fetch = fast_read(src, 3);
				lits = 0;
			}
			else
			{
				lits++;
				*dst = *src;
				src++;
				dst++;
				cword_val = (cword_val >> 1);
#ifdef X86X64
				fetch = fast_read(src, 3);
#else
				fetch = (fetch >> 8 & 0xffff) | (*(src + 2) << 16);
#endif
			}
		}
#elif QLZ_COMPRESSION_LEVEL >= 2
		{
			const unsigned char *o, *offset2;
			ui32 hash, matchlen, k, m, best_k = 0;
			unsigned char c;
			size_t remaining = (last_byte - UNCOMPRESSED_END - src + 1) > 255 ? 255 : (last_byte - UNCOMPRESSED_END - src + 1);
			(void)best_k;
		

			//hash = hashat(src);
			fetch = fast_read(src, 3);
			hash = hash_func(fetch);

			c = state->hash_counter[hash];

			offset2 = state->hash[hash].offset[0];
			if(offset2 < src - MINOFFSET && c > 0 && ((fast_read(offset2, 3) ^ fetch) & 0xffffff) == 0)
			{	
				matchlen = 3;
				if(*(offset2 + matchlen) == *(src + matchlen))
				{
					matchlen = 4;
					while(*(offset2 + matchlen) == *(src + matchlen) && matchlen < remaining)
						matchlen++;
				}
			}
			else
				matchlen = 0;
			for(k = 1; k < QLZ_POINTERS && c > k; k++)
			{
				o = state->hash[hash].offset[k];
#if QLZ_COMPRESSION_LEVEL == 3
				if(((fast_read(o, 3) ^ fetch) & 0xffffff) == 0 && o < src - MINOFFSET)
#elif QLZ_COMPRESSION_LEVEL == 2
				if(*(src + matchlen) == *(o + matchlen)	&& ((fast_read(o, 3) ^ fetch) & 0xffffff) == 0 && o < src - MINOFFSET)
#endif
				{	
					m = 3;
					while(*(o + m) == *(src + m) && m < remaining)
						m++;
#if QLZ_COMPRESSION_LEVEL == 3
					if ((m > matchlen) || (m == matchlen && o > offset2))
#elif QLZ_COMPRESSION_LEVEL == 2
					if (m > matchlen)
#endif
					{
						offset2 = o;
						matchlen = m;
						best_k = k;
					}
				}
			}
			o = offset2;
			state->hash[hash].offset[c & (QLZ_POINTERS - 1)] = src;
			c++;
			state->hash_counter[hash] = c;

#if QLZ_COMPRESSION_LEVEL == 3
			if(matchlen > 2 && src - o < 131071)
			{
				ui32 u;
				size_t offset = src - o;

				for(u = 1; u < matchlen; u++)
				{	
					hash = hashat(src + u);
					c = state->hash_counter[hash]++;
					state->hash[hash].offset[c & (QLZ_POINTERS - 1)] = src + u;
				}

				cword_val = (cword_val >> 1) | (1U << 31);
				src += matchlen;

				if(matchlen == 3 && offset <= 63)
				{
					*dst = (unsigned char)(offset << 2);
					dst++;
				}
				else if (matchlen == 3 && offset <= 16383)
				{
					ui32 f = (ui32)((offset << 2) | 1);
					fast_write(f, dst, 2);
					dst += 2;
				}		
				else if (matchlen <= 18 && offset <= 1023)
				{
					ui32 f = ((matchlen - 3) << 2) | ((ui32)offset << 6) | 2;
					fast_write(f, dst, 2);
					dst += 2;
				}

				else if(matchlen <= 33)
				{
					ui32 f = ((matchlen - 2) << 2) | ((ui32)offset << 7) | 3;
					fast_write(f, dst, 3);
					dst += 3;
				}
				else
				{
					ui32 f = ((matchlen - 3) << 7) | ((ui32)offset << 15) | 3;
					fast_write(f, dst, 4);
					dst += 4;
				}
			}
			else
			{
				*dst = *src;
				src++;
				dst++;
				cword_val = (cword_val >> 1);
			}
#elif QLZ_COMPRESSION_LEVEL == 2

			if(matchlen > 2)
			{
				cword_val = (cword_val >> 1) | (1U << 31);
				src += matchlen;			

				if (matchlen < 10)
				{			
					ui32 f = best_k | ((matchlen - 2) << 2) | (hash << 5);
					fast_write(f, dst, 2);
					dst += 2;
				}
				else
				{
					ui32 f = best_k | (matchlen << 16) | (hash << 5);
					fast_write(f, dst, 3);
					dst += 3;
				}
			}
			else
			{
				*dst = *src;
				src++;
				dst++;
				cword_val = (cword_val >> 1);
			}
#endif
		}
#endif
	}
	while (src <= last_byte)
	{
		if ((cword_val & 1) == 1)
		{
			fast_write((cword_val >> 1) | (1U << 31), cword_ptr, CWORD_LEN);
			cword_ptr = dst;
			dst += CWORD_LEN;
			cword_val = 1U << 31;
		}
#if QLZ_COMPRESSION_LEVEL < 3
		if (src <= last_byte - 3)
		{
#if QLZ_COMPRESSION_LEVEL == 1
			ui32 hash, fetch;
			fetch = fast_read(src, 3);
			hash = hash_func(fetch);
			state->hash[hash].offset = CAST(src - OFFSET_BASE);
			state->hash[hash].cache = fetch;
#elif QLZ_COMPRESSION_LEVEL == 2
			ui32 hash;
			unsigned char c;
			hash = hashat(src);
			c = state->hash_counter[hash];
			state->hash[hash].offset[c & (QLZ_POINTERS - 1)] = src;
			c++;
			state->hash_counter[hash] = c;
#endif
		}
#endif
		*dst = *src;
		src++;
		dst++;
		cword_val = (cword_val >> 1);
	}

	while((cword_val & 1) != 1)
		cword_val = (cword_val >> 1);

	fast_write((cword_val >> 1) | (1U << 31), cword_ptr, CWORD_LEN);

	// min. size must be 9 bytes so that the qlz_size functions can take 9 bytes as argument
	return dst - destination < 9 ? 9 : dst - destination;
}

static size_t qlz_decompress_core(const unsigned char *source, unsigned char *destination, size_t size, qlz_state_decompress *state, const unsigned char *history)
{
	const unsigned char *src = source + qlz_size_header((const char *)source);
	unsigned char *dst = destination;
	const unsigned char *last_destination_byte = destination + size - 1;
	ui32 cword_val = 1;
	const unsigned char *last_matchstart = last_destination_byte - UNCONDITIONAL_MATCHLEN - UNCOMPRESSED_END;
	unsigned char *last_hashed = destination - 1;
	const unsigned char *last_source_byte = source + qlz_size_compressed((const char *)source) - 1;
	static const ui32 bitlut[16] = {4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0};

	(void) last_source_byte;
	(void) last_hashed;
	(void) state;
	(void) history;

	for(;;) 
	{
		ui32 fetch;

		if (cword_val == 1)
		{
#ifdef QLZ_MEMORY_SAFE
			if(src + CWORD_LEN - 1 > last_source_byte)
				return 0;
#endif
			cword_val = fast_read(src, CWORD_LEN);
			src += CWORD_LEN;
		}

#ifdef QLZ_MEMORY_SAFE
			if(src + 4 - 1 > last_source_byte)
				return 0;
#endif

		fetch = fast_read(src, 4);

		if ((cword_val & 1) == 1)
		{
			ui32 matchlen;
			const unsigned char *offset2;

#if QLZ_COMPRESSION_LEVEL == 1
			ui32 hash;
			cword_val = cword_val >> 1;
			hash = (fetch >> 4) & 0xfff;
			offset2 = (const unsigned char *)(size_t)state->hash[hash].offset;

			if((fetch & 0xf) != 0)
			{
				matchlen = (fetch & 0xf) + 2;
				src += 2;
			}
			else
			{
				matchlen = *(src + 2);
				src += 3;							
			}	

#elif QLZ_COMPRESSION_LEVEL == 2
			ui32 hash;
			unsigned char c;
			cword_val = cword_val >> 1;
			hash = (fetch >> 5) & 0x7ff;
			c = (unsigned char)(fetch & 0x3);
			offset2 = state->hash[hash].offset[c];

			if((fetch & (28)) != 0)
			{
				matchlen = ((fetch >> 2) & 0x7) + 2;
				src += 2;
			}
			else
			{
				matchlen = *(src + 2);
				src += 3;							
			}	

#elif QLZ_COMPRESSION_LEVEL == 3
			ui32 offset;
			cword_val = cword_val >> 1;
			if ((fetch & 3) == 0)
			{
				offset = (fetch & 0xff) >> 2;
				matchlen = 3;
				src++;
			}
			else if ((fetch & 2) == 0)
			{
				offset = (fetch & 0xffff) >> 2;
				matchlen = 3;
				src += 2;
			}
			else if ((fetch & 1) == 0)
			{
				offset = (fetch & 0xffff) >> 6;
				matchlen = ((fetch >> 2) & 15) + 3;
				src += 2;
			}
			else if ((fetch & 127) != 3)
			{
				offset = (fetch >> 7) & 0x1ffff;
				matchlen = ((fetch >> 2) & 0x1f) + 2;
				src += 3;
			}
			else
			{
				offset = (fetch >> 15);
				matchlen = ((fetch >> 7) & 255) + 3;
				src += 4;
			}

			offset2 = dst - offset;
#endif
	
#ifdef QLZ_MEMORY_SAFE
			if(offset2 < history || offset2 > dst - MINOFFSET - 1)
				return 0;

			if(matchlen > (ui32)(last_destination_byte - dst - UNCOMPRESSED_END + 1))
				return 0;
#endif

			memcpy_up(dst, offset2, matchlen);
			dst += matchlen;

#if QLZ_COMPRESSION_LEVEL <= 2
			update_hash_upto(state, &last_hashed, dst - matchlen);
			last_hashed = dst - 1;
#endif
		}
		else
		{
			if (dst < last_matchstart)
			{
				unsigned int n = bitlut[cword_val & 0xf];
#ifdef X86X64
				*(ui32 *)dst = *(ui32 *)src;
#else
				memcpy_up(dst, src, 4);
#endif
				cword_val = cword_val >> n;
				dst += n;
				src += n;
#if QLZ_COMPRESSION_LEVEL <= 2
				update_hash_upto(state, &last_hashed, dst - 3);		
#endif
			}
			else
			{			
				while(dst <= last_destination_byte)
				{
					if (cword_val == 1)
					{
						src += CWORD_LEN;
						cword_val = 1U << 31;
					}
#ifdef QLZ_MEMORY_SAFE
					if(src >= last_source_byte + 1)
						return 0;
#endif
					*dst = *src;
					dst++;
					src++;
					cword_val = cword_val >> 1;
				}

#if QLZ_COMPRESSION_LEVEL <= 2
				update_hash_upto(state, &last_hashed, last_destination_byte - 3); // todo, use constant
#endif
				return size;
			}

		}
	}
}

size_t qlz_compress(const void *source, char *destination, size_t size, qlz_state_compress *state)
{
	size_t r;
	ui32 compressed;
	size_t base;

	if(size == 0 || size > 0xffffffff - 400)
		return 0;

	if(size < 216)
		base = 3;
	else
		base = 9;

#if QLZ_STREAMING_BUFFER > 0
	if (state->stream_counter + size - 1 >= QLZ_STREAMING_BUFFER)
#endif
	{
		reset_table_compress(state);
		r = base + qlz_compress_core((const unsigned char *)source, (unsigned char*)destination + base, size, state);
#if QLZ_STREAMING_BUFFER > 0
		reset_table_compress(state);
#endif
		if(r == base)
		{
			memcpy(destination + base, source, size);
			r = size + base;
			compressed = 0;
		}
		else
		{
			compressed = 1;
		}
		state->stream_counter = 0;
	}
#if QLZ_STREAMING_BUFFER > 0
	else
	{
		unsigned char *src = state->stream_buffer + state->stream_counter;

		memcpy(src, source, size);
		r = base + qlz_compress_core(src, (unsigned char*)destination + base, size, state);

 		if(r == base)
		{
			memcpy(destination + base, src, size);
			r = size + base;
			compressed = 0;
			reset_table_compress(state);
		}
		else
		{
			compressed = 1;
		}
		state->stream_counter += size;
	}
#endif
	if(base == 3)
	{
		*destination = (unsigned char)(0 | compressed);
		*(destination + 1) = (unsigned char)r;
		*(destination + 2) = (unsigned char)size;
	}
	else
	{
		*destination = (unsigned char)(2 | compressed);
		fast_write((ui32)r, destination + 1, 4);
		fast_write((ui32)size, destination + 5, 4);
	}
	
	*destination |= (QLZ_COMPRESSION_LEVEL << 2);
	*destination |= (1 << 6);
	*destination |= ((QLZ_STREAMING_BUFFER == 0 ? 0 : (QLZ_STREAMING_BUFFER == 100000 ? 1 : (QLZ_STREAMING_BUFFER == 1000000 ? 2 : 3))) << 4);

// 76543210
// 01SSLLHC

	return r;
}

size_t qlz_decompress(const char *source, void *destination, qlz_state_decompress *state)
{
	size_t dsiz = qlz_size_decompressed(source);

#if QLZ_STREAMING_BUFFER > 0
	if (state->stream_counter + qlz_size_decompressed(source) - 1 >= QLZ_STREAMING_BUFFER) 
#endif
	{
		if((*source & 1) == 1)
		{
			reset_table_decompress(state);
			dsiz = qlz_decompress_core((const unsigned char *)source, (unsigned char *)destination, dsiz, state, (const unsigned char *)destination);
		}
		else
		{
			memcpy(destination, source + qlz_size_header(source), dsiz);
		}
		state->stream_counter = 0;
		reset_table_decompress(state);
	}
#if QLZ_STREAMING_BUFFER > 0
	else
	{
		unsigned char *dst = state->stream_buffer + state->stream_counter;
		if((*source & 1) == 1)
		{
			dsiz = qlz_decompress_core((const unsigned char *)source, dst, dsiz, state, (const unsigned char *)state->stream_buffer);
		}
		else
		{
			memcpy(dst, source + qlz_size_header(source), dsiz);
			reset_table_decompress(state);
		}
		memcpy(destination, dst, dsiz);
		state->stream_counter += dsiz;
	}
#endif
	return dsiz;
}