-
Notifications
You must be signed in to change notification settings - Fork 1.3k
/
lz4.c
2829 lines (2498 loc) · 115 KB
/
lz4.c
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
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
LZ4 - Fast LZ compression algorithm
Copyright (C) 2011-2023, Yann Collet.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
You can contact the author at :
- LZ4 homepage : http://www.lz4.org
- LZ4 source repository : https://github.com/lz4/lz4
*/
/*-************************************
* Tuning parameters
**************************************/
/*
* LZ4_HEAPMODE :
* Select how stateless compression functions like `LZ4_compress_default()`
* allocate memory for their hash table,
* in memory stack (0:default, fastest), or in memory heap (1:requires malloc()).
*/
#ifndef LZ4_HEAPMODE
# define LZ4_HEAPMODE 0
#endif
/*
* LZ4_ACCELERATION_DEFAULT :
* Select "acceleration" for LZ4_compress_fast() when parameter value <= 0
*/
#define LZ4_ACCELERATION_DEFAULT 1
/*
* LZ4_ACCELERATION_MAX :
* Any "acceleration" value higher than this threshold
* get treated as LZ4_ACCELERATION_MAX instead (fix #876)
*/
#define LZ4_ACCELERATION_MAX 65537
/*-************************************
* CPU Feature Detection
**************************************/
/* LZ4_FORCE_MEMORY_ACCESS
* By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
* Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
* The below switch allow to select different access method for improved performance.
* Method 0 (default) : use `memcpy()`. Safe and portable.
* Method 1 : `__packed` statement. It depends on compiler extension (ie, not portable).
* This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
* Method 2 : direct access. This method is portable but violate C standard.
* It can generate buggy code on targets which assembly generation depends on alignment.
* But in some circumstances, it's the only known way to get the most performance (ie GCC + ARMv6)
* See https://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
* Prefer these methods in priority order (0 > 1 > 2)
*/
#ifndef LZ4_FORCE_MEMORY_ACCESS /* can be defined externally */
# if defined(__GNUC__) && \
( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) \
|| defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
# define LZ4_FORCE_MEMORY_ACCESS 2
# elif (defined(__INTEL_COMPILER) && !defined(_WIN32)) || defined(__GNUC__) || defined(_MSC_VER)
# define LZ4_FORCE_MEMORY_ACCESS 1
# endif
#endif
/*
* LZ4_FORCE_SW_BITCOUNT
* Define this parameter if your target system or compiler does not support hardware bit count
*/
#if defined(_MSC_VER) && defined(_WIN32_WCE) /* Visual Studio for WinCE doesn't support Hardware bit count */
# undef LZ4_FORCE_SW_BITCOUNT /* avoid double def */
# define LZ4_FORCE_SW_BITCOUNT
#endif
/*-************************************
* Dependency
**************************************/
/*
* LZ4_SRC_INCLUDED:
* Amalgamation flag, whether lz4.c is included
*/
#ifndef LZ4_SRC_INCLUDED
# define LZ4_SRC_INCLUDED 1
#endif
#ifndef LZ4_DISABLE_DEPRECATE_WARNINGS
# define LZ4_DISABLE_DEPRECATE_WARNINGS /* due to LZ4_decompress_safe_withPrefix64k */
#endif
#ifndef LZ4_STATIC_LINKING_ONLY
# define LZ4_STATIC_LINKING_ONLY
#endif
#include "lz4.h"
/* see also "memory routines" below */
/*-************************************
* Compiler Options
**************************************/
#if defined(_MSC_VER) && (_MSC_VER >= 1400) /* Visual Studio 2005+ */
# include <intrin.h> /* only present in VS2005+ */
# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
# pragma warning(disable : 6237) /* disable: C6237: conditional expression is always 0 */
# pragma warning(disable : 6239) /* disable: C6239: (<non-zero constant> && <expression>) always evaluates to the result of <expression> */
# pragma warning(disable : 6240) /* disable: C6240: (<expression> && <non-zero constant>) always evaluates to the result of <expression> */
# pragma warning(disable : 6326) /* disable: C6326: Potential comparison of a constant with another constant */
#endif /* _MSC_VER */
#ifndef LZ4_FORCE_INLINE
# if defined (_MSC_VER) && !defined (__clang__) /* MSVC */
# define LZ4_FORCE_INLINE static __forceinline
# else
# if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */
# if defined (__GNUC__) || defined (__clang__)
# define LZ4_FORCE_INLINE static inline __attribute__((always_inline))
# else
# define LZ4_FORCE_INLINE static inline
# endif
# else
# define LZ4_FORCE_INLINE static
# endif /* __STDC_VERSION__ */
# endif /* _MSC_VER */
#endif /* LZ4_FORCE_INLINE */
/* LZ4_FORCE_O2 and LZ4_FORCE_INLINE
* gcc on ppc64le generates an unrolled SIMDized loop for LZ4_wildCopy8,
* together with a simple 8-byte copy loop as a fall-back path.
* However, this optimization hurts the decompression speed by >30%,
* because the execution does not go to the optimized loop
* for typical compressible data, and all of the preamble checks
* before going to the fall-back path become useless overhead.
* This optimization happens only with the -O3 flag, and -O2 generates
* a simple 8-byte copy loop.
* With gcc on ppc64le, all of the LZ4_decompress_* and LZ4_wildCopy8
* functions are annotated with __attribute__((optimize("O2"))),
* and also LZ4_wildCopy8 is forcibly inlined, so that the O2 attribute
* of LZ4_wildCopy8 does not affect the compression speed.
*/
#if defined(__PPC64__) && defined(__LITTLE_ENDIAN__) && defined(__GNUC__) && !defined(__clang__)
# define LZ4_FORCE_O2 __attribute__((optimize("O2")))
# undef LZ4_FORCE_INLINE
# define LZ4_FORCE_INLINE static __inline __attribute__((optimize("O2"),always_inline))
#else
# define LZ4_FORCE_O2
#endif
#if (defined(__GNUC__) && (__GNUC__ >= 3)) || (defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 800)) || defined(__clang__)
# define expect(expr,value) (__builtin_expect ((expr),(value)) )
#else
# define expect(expr,value) (expr)
#endif
#ifndef likely
#define likely(expr) expect((expr) != 0, 1)
#endif
#ifndef unlikely
#define unlikely(expr) expect((expr) != 0, 0)
#endif
/* Should the alignment test prove unreliable, for some reason,
* it can be disabled by setting LZ4_ALIGN_TEST to 0 */
#ifndef LZ4_ALIGN_TEST /* can be externally provided */
# define LZ4_ALIGN_TEST 1
#endif
/*-************************************
* Memory routines
**************************************/
/*! LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION :
* Disable relatively high-level LZ4/HC functions that use dynamic memory
* allocation functions (malloc(), calloc(), free()).
*
* Note that this is a compile-time switch. And since it disables
* public/stable LZ4 v1 API functions, we don't recommend using this
* symbol to generate a library for distribution.
*
* The following public functions are removed when this symbol is defined.
* - lz4 : LZ4_createStream, LZ4_freeStream,
* LZ4_createStreamDecode, LZ4_freeStreamDecode, LZ4_create (deprecated)
* - lz4hc : LZ4_createStreamHC, LZ4_freeStreamHC,
* LZ4_createHC (deprecated), LZ4_freeHC (deprecated)
* - lz4frame, lz4file : All LZ4F_* functions
*/
#if defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
# define ALLOC(s) lz4_error_memory_allocation_is_disabled
# define ALLOC_AND_ZERO(s) lz4_error_memory_allocation_is_disabled
# define FREEMEM(p) lz4_error_memory_allocation_is_disabled
#elif defined(LZ4_USER_MEMORY_FUNCTIONS)
/* memory management functions can be customized by user project.
* Below functions must exist somewhere in the Project
* and be available at link time */
void* LZ4_malloc(size_t s);
void* LZ4_calloc(size_t n, size_t s);
void LZ4_free(void* p);
# define ALLOC(s) LZ4_malloc(s)
# define ALLOC_AND_ZERO(s) LZ4_calloc(1,s)
# define FREEMEM(p) LZ4_free(p)
#else
# include <stdlib.h> /* malloc, calloc, free */
# define ALLOC(s) malloc(s)
# define ALLOC_AND_ZERO(s) calloc(1,s)
# define FREEMEM(p) free(p)
#endif
#if ! LZ4_FREESTANDING
# include <string.h> /* memset, memcpy */
#endif
#if !defined(LZ4_memset)
# define LZ4_memset(p,v,s) memset((p),(v),(s))
#endif
#define MEM_INIT(p,v,s) LZ4_memset((p),(v),(s))
/*-************************************
* Common Constants
**************************************/
#define MINMATCH 4
#define WILDCOPYLENGTH 8
#define LASTLITERALS 5 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MFLIMIT 12 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MATCH_SAFEGUARD_DISTANCE ((2*WILDCOPYLENGTH) - MINMATCH) /* ensure it's possible to write 2 x wildcopyLength without overflowing output buffer */
#define FASTLOOP_SAFE_DISTANCE 64
static const int LZ4_minLength = (MFLIMIT+1);
#define KB *(1 <<10)
#define MB *(1 <<20)
#define GB *(1U<<30)
#define LZ4_DISTANCE_ABSOLUTE_MAX 65535
#if (LZ4_DISTANCE_MAX > LZ4_DISTANCE_ABSOLUTE_MAX) /* max supported by LZ4 format */
# error "LZ4_DISTANCE_MAX is too big : must be <= 65535"
#endif
#define ML_BITS 4
#define ML_MASK ((1U<<ML_BITS)-1)
#define RUN_BITS (8-ML_BITS)
#define RUN_MASK ((1U<<RUN_BITS)-1)
/*-************************************
* Error detection
**************************************/
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=1)
# include <assert.h>
#else
# ifndef assert
# define assert(condition) ((void)0)
# endif
#endif
#define LZ4_STATIC_ASSERT(c) { enum { LZ4_static_assert = 1/(int)(!!(c)) }; } /* use after variable declarations */
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=2)
# include <stdio.h>
static int g_debuglog_enable = 1;
# define DEBUGLOG(l, ...) { \
if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) { \
fprintf(stderr, __FILE__ " %i: ", __LINE__); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, " \n"); \
} }
#else
# define DEBUGLOG(l, ...) {} /* disabled */
#endif
static int LZ4_isAligned(const void* ptr, size_t alignment)
{
return ((size_t)ptr & (alignment -1)) == 0;
}
/*-************************************
* Types
**************************************/
#include <limits.h>
#if defined(__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
# include <stdint.h>
typedef uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
typedef int32_t S32;
typedef uint64_t U64;
typedef uintptr_t uptrval;
#else
# if UINT_MAX != 4294967295UL
# error "LZ4 code (when not C++ or C99) assumes that sizeof(int) == 4"
# endif
typedef unsigned char BYTE;
typedef unsigned short U16;
typedef unsigned int U32;
typedef signed int S32;
typedef unsigned long long U64;
typedef size_t uptrval; /* generally true, except OpenVMS-64 */
#endif
#if defined(__x86_64__)
typedef U64 reg_t; /* 64-bits in x32 mode */
#else
typedef size_t reg_t; /* 32-bits in x32 mode */
#endif
typedef enum {
notLimited = 0,
limitedOutput = 1,
fillOutput = 2
} limitedOutput_directive;
/*-************************************
* Reading and writing into memory
**************************************/
/**
* LZ4 relies on memcpy with a constant size being inlined. In freestanding
* environments, the compiler can't assume the implementation of memcpy() is
* standard compliant, so it can't apply its specialized memcpy() inlining
* logic. When possible, use __builtin_memcpy() to tell the compiler to analyze
* memcpy() as if it were standard compliant, so it can inline it in freestanding
* environments. This is needed when decompressing the Linux Kernel, for example.
*/
#if !defined(LZ4_memcpy)
# if defined(__GNUC__) && (__GNUC__ >= 4)
# define LZ4_memcpy(dst, src, size) __builtin_memcpy(dst, src, size)
# else
# define LZ4_memcpy(dst, src, size) memcpy(dst, src, size)
# endif
#endif
#if !defined(LZ4_memmove)
# if defined(__GNUC__) && (__GNUC__ >= 4)
# define LZ4_memmove __builtin_memmove
# else
# define LZ4_memmove memmove
# endif
#endif
static unsigned LZ4_isLittleEndian(void)
{
const union { U32 u; BYTE c[4]; } one = { 1 }; /* don't use static : performance detrimental */
return one.c[0];
}
#if defined(__GNUC__) || defined(__INTEL_COMPILER)
#define LZ4_PACK( __Declaration__ ) __Declaration__ __attribute__((__packed__))
#elif defined(_MSC_VER)
#define LZ4_PACK( __Declaration__ ) __pragma( pack(push, 1) ) __Declaration__ __pragma( pack(pop))
#endif
#if defined(LZ4_FORCE_MEMORY_ACCESS) && (LZ4_FORCE_MEMORY_ACCESS==2)
/* lie to the compiler about data alignment; use with caution */
static U16 LZ4_read16(const void* memPtr) { return *(const U16*) memPtr; }
static U32 LZ4_read32(const void* memPtr) { return *(const U32*) memPtr; }
static reg_t LZ4_read_ARCH(const void* memPtr) { return *(const reg_t*) memPtr; }
static void LZ4_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
static void LZ4_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; }
#elif defined(LZ4_FORCE_MEMORY_ACCESS) && (LZ4_FORCE_MEMORY_ACCESS==1)
/* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
/* currently only defined for gcc and icc */
LZ4_PACK(typedef struct { U16 u16; }) LZ4_unalign16;
LZ4_PACK(typedef struct { U32 u32; }) LZ4_unalign32;
LZ4_PACK(typedef struct { reg_t uArch; }) LZ4_unalignST;
static U16 LZ4_read16(const void* ptr) { return ((const LZ4_unalign16*)ptr)->u16; }
static U32 LZ4_read32(const void* ptr) { return ((const LZ4_unalign32*)ptr)->u32; }
static reg_t LZ4_read_ARCH(const void* ptr) { return ((const LZ4_unalignST*)ptr)->uArch; }
static void LZ4_write16(void* memPtr, U16 value) { ((LZ4_unalign16*)memPtr)->u16 = value; }
static void LZ4_write32(void* memPtr, U32 value) { ((LZ4_unalign32*)memPtr)->u32 = value; }
#else /* safe and portable access using memcpy() */
static U16 LZ4_read16(const void* memPtr)
{
U16 val; LZ4_memcpy(&val, memPtr, sizeof(val)); return val;
}
static U32 LZ4_read32(const void* memPtr)
{
U32 val; LZ4_memcpy(&val, memPtr, sizeof(val)); return val;
}
static reg_t LZ4_read_ARCH(const void* memPtr)
{
reg_t val; LZ4_memcpy(&val, memPtr, sizeof(val)); return val;
}
static void LZ4_write16(void* memPtr, U16 value)
{
LZ4_memcpy(memPtr, &value, sizeof(value));
}
static void LZ4_write32(void* memPtr, U32 value)
{
LZ4_memcpy(memPtr, &value, sizeof(value));
}
#endif /* LZ4_FORCE_MEMORY_ACCESS */
static U16 LZ4_readLE16(const void* memPtr)
{
if (LZ4_isLittleEndian()) {
return LZ4_read16(memPtr);
} else {
const BYTE* p = (const BYTE*)memPtr;
return (U16)((U16)p[0] | (p[1]<<8));
}
}
#ifdef LZ4_STATIC_LINKING_ONLY_ENDIANNESS_INDEPENDENT_OUTPUT
static U32 LZ4_readLE32(const void* memPtr)
{
if (LZ4_isLittleEndian()) {
return LZ4_read32(memPtr);
} else {
const BYTE* p = (const BYTE*)memPtr;
return (U32)p[0] | (p[1]<<8) | (p[2]<<16) | (p[3]<<24);
}
}
#endif
static void LZ4_writeLE16(void* memPtr, U16 value)
{
if (LZ4_isLittleEndian()) {
LZ4_write16(memPtr, value);
} else {
BYTE* p = (BYTE*)memPtr;
p[0] = (BYTE) value;
p[1] = (BYTE)(value>>8);
}
}
/* customized variant of memcpy, which can overwrite up to 8 bytes beyond dstEnd */
LZ4_FORCE_INLINE
void LZ4_wildCopy8(void* dstPtr, const void* srcPtr, void* dstEnd)
{
BYTE* d = (BYTE*)dstPtr;
const BYTE* s = (const BYTE*)srcPtr;
BYTE* const e = (BYTE*)dstEnd;
do { LZ4_memcpy(d,s,8); d+=8; s+=8; } while (d<e);
}
static const unsigned inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
#ifndef LZ4_FAST_DEC_LOOP
# if defined __i386__ || defined _M_IX86 || defined __x86_64__ || defined _M_X64
# define LZ4_FAST_DEC_LOOP 1
# elif defined(__aarch64__) && defined(__APPLE__)
# define LZ4_FAST_DEC_LOOP 1
# elif defined(__aarch64__) && !defined(__clang__)
/* On non-Apple aarch64, we disable this optimization for clang because
* on certain mobile chipsets, performance is reduced with clang. For
* more information refer to https://github.com/lz4/lz4/pull/707 */
# define LZ4_FAST_DEC_LOOP 1
# else
# define LZ4_FAST_DEC_LOOP 0
# endif
#endif
#if LZ4_FAST_DEC_LOOP
LZ4_FORCE_INLINE void
LZ4_memcpy_using_offset_base(BYTE* dstPtr, const BYTE* srcPtr, BYTE* dstEnd, const size_t offset)
{
assert(srcPtr + offset == dstPtr);
if (offset < 8) {
LZ4_write32(dstPtr, 0); /* silence an msan warning when offset==0 */
dstPtr[0] = srcPtr[0];
dstPtr[1] = srcPtr[1];
dstPtr[2] = srcPtr[2];
dstPtr[3] = srcPtr[3];
srcPtr += inc32table[offset];
LZ4_memcpy(dstPtr+4, srcPtr, 4);
srcPtr -= dec64table[offset];
dstPtr += 8;
} else {
LZ4_memcpy(dstPtr, srcPtr, 8);
dstPtr += 8;
srcPtr += 8;
}
LZ4_wildCopy8(dstPtr, srcPtr, dstEnd);
}
/* customized variant of memcpy, which can overwrite up to 32 bytes beyond dstEnd
* this version copies two times 16 bytes (instead of one time 32 bytes)
* because it must be compatible with offsets >= 16. */
LZ4_FORCE_INLINE void
LZ4_wildCopy32(void* dstPtr, const void* srcPtr, void* dstEnd)
{
BYTE* d = (BYTE*)dstPtr;
const BYTE* s = (const BYTE*)srcPtr;
BYTE* const e = (BYTE*)dstEnd;
do { LZ4_memcpy(d,s,16); LZ4_memcpy(d+16,s+16,16); d+=32; s+=32; } while (d<e);
}
/* LZ4_memcpy_using_offset() presumes :
* - dstEnd >= dstPtr + MINMATCH
* - there is at least 12 bytes available to write after dstEnd */
LZ4_FORCE_INLINE void
LZ4_memcpy_using_offset(BYTE* dstPtr, const BYTE* srcPtr, BYTE* dstEnd, const size_t offset)
{
BYTE v[8];
assert(dstEnd >= dstPtr + MINMATCH);
switch(offset) {
case 1:
MEM_INIT(v, *srcPtr, 8);
break;
case 2:
LZ4_memcpy(v, srcPtr, 2);
LZ4_memcpy(&v[2], srcPtr, 2);
#if defined(_MSC_VER) && (_MSC_VER <= 1937) /* MSVC 2022 ver 17.7 or earlier */
# pragma warning(push)
# pragma warning(disable : 6385) /* warning C6385: Reading invalid data from 'v'. */
#endif
LZ4_memcpy(&v[4], v, 4);
#if defined(_MSC_VER) && (_MSC_VER <= 1937) /* MSVC 2022 ver 17.7 or earlier */
# pragma warning(pop)
#endif
break;
case 4:
LZ4_memcpy(v, srcPtr, 4);
LZ4_memcpy(&v[4], srcPtr, 4);
break;
default:
LZ4_memcpy_using_offset_base(dstPtr, srcPtr, dstEnd, offset);
return;
}
LZ4_memcpy(dstPtr, v, 8);
dstPtr += 8;
while (dstPtr < dstEnd) {
LZ4_memcpy(dstPtr, v, 8);
dstPtr += 8;
}
}
#endif
/*-************************************
* Common functions
**************************************/
static unsigned LZ4_NbCommonBytes (reg_t val)
{
assert(val != 0);
if (LZ4_isLittleEndian()) {
if (sizeof(val) == 8) {
# if defined(_MSC_VER) && (_MSC_VER >= 1800) && (defined(_M_AMD64) && !defined(_M_ARM64EC)) && !defined(LZ4_FORCE_SW_BITCOUNT)
/*-*************************************************************************************************
* ARM64EC is a Microsoft-designed ARM64 ABI compatible with AMD64 applications on ARM64 Windows 11.
* The ARM64EC ABI does not support AVX/AVX2/AVX512 instructions, nor their relevant intrinsics
* including _tzcnt_u64. Therefore, we need to neuter the _tzcnt_u64 code path for ARM64EC.
****************************************************************************************************/
# if defined(__clang__) && (__clang_major__ < 10)
/* Avoid undefined clang-cl intrinsics issue.
* See https://github.com/lz4/lz4/pull/1017 for details. */
return (unsigned)__builtin_ia32_tzcnt_u64(val) >> 3;
# else
/* x64 CPUS without BMI support interpret `TZCNT` as `REP BSF` */
return (unsigned)_tzcnt_u64(val) >> 3;
# endif
# elif defined(_MSC_VER) && defined(_WIN64) && !defined(LZ4_FORCE_SW_BITCOUNT)
unsigned long r = 0;
_BitScanForward64(&r, (U64)val);
return (unsigned)r >> 3;
# elif (defined(__clang__) || (defined(__GNUC__) && ((__GNUC__ > 3) || \
((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))))) && \
!defined(LZ4_FORCE_SW_BITCOUNT)
return (unsigned)__builtin_ctzll((U64)val) >> 3;
# else
const U64 m = 0x0101010101010101ULL;
val ^= val - 1;
return (unsigned)(((U64)((val & (m - 1)) * m)) >> 56);
# endif
} else /* 32 bits */ {
# if defined(_MSC_VER) && (_MSC_VER >= 1400) && !defined(LZ4_FORCE_SW_BITCOUNT)
unsigned long r;
_BitScanForward(&r, (U32)val);
return (unsigned)r >> 3;
# elif (defined(__clang__) || (defined(__GNUC__) && ((__GNUC__ > 3) || \
((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))))) && \
!defined(__TINYC__) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (unsigned)__builtin_ctz((U32)val) >> 3;
# else
const U32 m = 0x01010101;
return (unsigned)((((val - 1) ^ val) & (m - 1)) * m) >> 24;
# endif
}
} else /* Big Endian CPU */ {
if (sizeof(val)==8) {
# if (defined(__clang__) || (defined(__GNUC__) && ((__GNUC__ > 3) || \
((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))))) && \
!defined(__TINYC__) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (unsigned)__builtin_clzll((U64)val) >> 3;
# else
#if 1
/* this method is probably faster,
* but adds a 128 bytes lookup table */
static const unsigned char ctz7_tab[128] = {
7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
};
U64 const mask = 0x0101010101010101ULL;
U64 const t = (((val >> 8) - mask) | val) & mask;
return ctz7_tab[(t * 0x0080402010080402ULL) >> 57];
#else
/* this method doesn't consume memory space like the previous one,
* but it contains several branches,
* that may end up slowing execution */
static const U32 by32 = sizeof(val)*4; /* 32 on 64 bits (goal), 16 on 32 bits.
Just to avoid some static analyzer complaining about shift by 32 on 32-bits target.
Note that this code path is never triggered in 32-bits mode. */
unsigned r;
if (!(val>>by32)) { r=4; } else { r=0; val>>=by32; }
if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
r += (!val);
return r;
#endif
# endif
} else /* 32 bits */ {
# if (defined(__clang__) || (defined(__GNUC__) && ((__GNUC__ > 3) || \
((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))))) && \
!defined(LZ4_FORCE_SW_BITCOUNT)
return (unsigned)__builtin_clz((U32)val) >> 3;
# else
val >>= 8;
val = ((((val + 0x00FFFF00) | 0x00FFFFFF) + val) |
(val + 0x00FF0000)) >> 24;
return (unsigned)val ^ 3;
# endif
}
}
}
#define STEPSIZE sizeof(reg_t)
LZ4_FORCE_INLINE
unsigned LZ4_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* pInLimit)
{
const BYTE* const pStart = pIn;
if (likely(pIn < pInLimit-(STEPSIZE-1))) {
reg_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
if (!diff) {
pIn+=STEPSIZE; pMatch+=STEPSIZE;
} else {
return LZ4_NbCommonBytes(diff);
} }
while (likely(pIn < pInLimit-(STEPSIZE-1))) {
reg_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
if (!diff) { pIn+=STEPSIZE; pMatch+=STEPSIZE; continue; }
pIn += LZ4_NbCommonBytes(diff);
return (unsigned)(pIn - pStart);
}
if ((STEPSIZE==8) && (pIn<(pInLimit-3)) && (LZ4_read32(pMatch) == LZ4_read32(pIn))) { pIn+=4; pMatch+=4; }
if ((pIn<(pInLimit-1)) && (LZ4_read16(pMatch) == LZ4_read16(pIn))) { pIn+=2; pMatch+=2; }
if ((pIn<pInLimit) && (*pMatch == *pIn)) pIn++;
return (unsigned)(pIn - pStart);
}
#ifndef LZ4_COMMONDEFS_ONLY
/*-************************************
* Local Constants
**************************************/
static const int LZ4_64Klimit = ((64 KB) + (MFLIMIT-1));
static const U32 LZ4_skipTrigger = 6; /* Increase this value ==> compression run slower on incompressible data */
/*-************************************
* Local Structures and types
**************************************/
typedef enum { clearedTable = 0, byPtr, byU32, byU16 } tableType_t;
/**
* This enum distinguishes several different modes of accessing previous
* content in the stream.
*
* - noDict : There is no preceding content.
* - withPrefix64k : Table entries up to ctx->dictSize before the current blob
* blob being compressed are valid and refer to the preceding
* content (of length ctx->dictSize), which is available
* contiguously preceding in memory the content currently
* being compressed.
* - usingExtDict : Like withPrefix64k, but the preceding content is somewhere
* else in memory, starting at ctx->dictionary with length
* ctx->dictSize.
* - usingDictCtx : Everything concerning the preceding content is
* in a separate context, pointed to by ctx->dictCtx.
* ctx->dictionary, ctx->dictSize, and table entries
* in the current context that refer to positions
* preceding the beginning of the current compression are
* ignored. Instead, ctx->dictCtx->dictionary and ctx->dictCtx
* ->dictSize describe the location and size of the preceding
* content, and matches are found by looking in the ctx
* ->dictCtx->hashTable.
*/
typedef enum { noDict = 0, withPrefix64k, usingExtDict, usingDictCtx } dict_directive;
typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
/*-************************************
* Local Utils
**************************************/
int LZ4_versionNumber (void) { return LZ4_VERSION_NUMBER; }
const char* LZ4_versionString(void) { return LZ4_VERSION_STRING; }
int LZ4_compressBound(int isize) { return LZ4_COMPRESSBOUND(isize); }
int LZ4_sizeofState(void) { return sizeof(LZ4_stream_t); }
/*-****************************************
* Internal Definitions, used only in Tests
*******************************************/
#if defined (__cplusplus)
extern "C" {
#endif
int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_dict, const char* source, char* dest, int srcSize);
int LZ4_decompress_safe_forceExtDict(const char* source, char* dest,
int compressedSize, int maxOutputSize,
const void* dictStart, size_t dictSize);
int LZ4_decompress_safe_partial_forceExtDict(const char* source, char* dest,
int compressedSize, int targetOutputSize, int dstCapacity,
const void* dictStart, size_t dictSize);
#if defined (__cplusplus)
}
#endif
/*-******************************
* Compression functions
********************************/
LZ4_FORCE_INLINE U32 LZ4_hash4(U32 sequence, tableType_t const tableType)
{
if (tableType == byU16)
return ((sequence * 2654435761U) >> ((MINMATCH*8)-(LZ4_HASHLOG+1)));
else
return ((sequence * 2654435761U) >> ((MINMATCH*8)-LZ4_HASHLOG));
}
LZ4_FORCE_INLINE U32 LZ4_hash5(U64 sequence, tableType_t const tableType)
{
const U32 hashLog = (tableType == byU16) ? LZ4_HASHLOG+1 : LZ4_HASHLOG;
if (LZ4_isLittleEndian()) {
const U64 prime5bytes = 889523592379ULL;
return (U32)(((sequence << 24) * prime5bytes) >> (64 - hashLog));
} else {
const U64 prime8bytes = 11400714785074694791ULL;
return (U32)(((sequence >> 24) * prime8bytes) >> (64 - hashLog));
}
}
LZ4_FORCE_INLINE U32 LZ4_hashPosition(const void* const p, tableType_t const tableType)
{
if ((sizeof(reg_t)==8) && (tableType != byU16)) return LZ4_hash5(LZ4_read_ARCH(p), tableType);
#ifdef LZ4_STATIC_LINKING_ONLY_ENDIANNESS_INDEPENDENT_OUTPUT
return LZ4_hash4(LZ4_readLE32(p), tableType);
#else
return LZ4_hash4(LZ4_read32(p), tableType);
#endif
}
LZ4_FORCE_INLINE void LZ4_clearHash(U32 h, void* tableBase, tableType_t const tableType)
{
switch (tableType)
{
default: /* fallthrough */
case clearedTable: { /* illegal! */ assert(0); return; }
case byPtr: { const BYTE** hashTable = (const BYTE**)tableBase; hashTable[h] = NULL; return; }
case byU32: { U32* hashTable = (U32*) tableBase; hashTable[h] = 0; return; }
case byU16: { U16* hashTable = (U16*) tableBase; hashTable[h] = 0; return; }
}
}
LZ4_FORCE_INLINE void LZ4_putIndexOnHash(U32 idx, U32 h, void* tableBase, tableType_t const tableType)
{
switch (tableType)
{
default: /* fallthrough */
case clearedTable: /* fallthrough */
case byPtr: { /* illegal! */ assert(0); return; }
case byU32: { U32* hashTable = (U32*) tableBase; hashTable[h] = idx; return; }
case byU16: { U16* hashTable = (U16*) tableBase; assert(idx < 65536); hashTable[h] = (U16)idx; return; }
}
}
/* LZ4_putPosition*() : only used in byPtr mode */
LZ4_FORCE_INLINE void LZ4_putPositionOnHash(const BYTE* p, U32 h,
void* tableBase, tableType_t const tableType)
{
const BYTE** const hashTable = (const BYTE**)tableBase;
assert(tableType == byPtr); (void)tableType;
hashTable[h] = p;
}
LZ4_FORCE_INLINE void LZ4_putPosition(const BYTE* p, void* tableBase, tableType_t tableType)
{
U32 const h = LZ4_hashPosition(p, tableType);
LZ4_putPositionOnHash(p, h, tableBase, tableType);
}
/* LZ4_getIndexOnHash() :
* Index of match position registered in hash table.
* hash position must be calculated by using base+index, or dictBase+index.
* Assumption 1 : only valid if tableType == byU32 or byU16.
* Assumption 2 : h is presumed valid (within limits of hash table)
*/
LZ4_FORCE_INLINE U32 LZ4_getIndexOnHash(U32 h, const void* tableBase, tableType_t tableType)
{
LZ4_STATIC_ASSERT(LZ4_MEMORY_USAGE > 2);
if (tableType == byU32) {
const U32* const hashTable = (const U32*) tableBase;
assert(h < (1U << (LZ4_MEMORY_USAGE-2)));
return hashTable[h];
}
if (tableType == byU16) {
const U16* const hashTable = (const U16*) tableBase;
assert(h < (1U << (LZ4_MEMORY_USAGE-1)));
return hashTable[h];
}
assert(0); return 0; /* forbidden case */
}
static const BYTE* LZ4_getPositionOnHash(U32 h, const void* tableBase, tableType_t tableType)
{
assert(tableType == byPtr); (void)tableType;
{ const BYTE* const* hashTable = (const BYTE* const*) tableBase; return hashTable[h]; }
}
LZ4_FORCE_INLINE const BYTE*
LZ4_getPosition(const BYTE* p,
const void* tableBase, tableType_t tableType)
{
U32 const h = LZ4_hashPosition(p, tableType);
return LZ4_getPositionOnHash(h, tableBase, tableType);
}
LZ4_FORCE_INLINE void
LZ4_prepareTable(LZ4_stream_t_internal* const cctx,
const int inputSize,
const tableType_t tableType) {
/* If the table hasn't been used, it's guaranteed to be zeroed out, and is
* therefore safe to use no matter what mode we're in. Otherwise, we figure
* out if it's safe to leave as is or whether it needs to be reset.
*/
if ((tableType_t)cctx->tableType != clearedTable) {
assert(inputSize >= 0);
if ((tableType_t)cctx->tableType != tableType
|| ((tableType == byU16) && cctx->currentOffset + (unsigned)inputSize >= 0xFFFFU)
|| ((tableType == byU32) && cctx->currentOffset > 1 GB)
|| tableType == byPtr
|| inputSize >= 4 KB)
{
DEBUGLOG(4, "LZ4_prepareTable: Resetting table in %p", cctx);
MEM_INIT(cctx->hashTable, 0, LZ4_HASHTABLESIZE);
cctx->currentOffset = 0;
cctx->tableType = (U32)clearedTable;
} else {
DEBUGLOG(4, "LZ4_prepareTable: Re-use hash table (no reset)");
}
}
/* Adding a gap, so all previous entries are > LZ4_DISTANCE_MAX back,
* is faster than compressing without a gap.
* However, compressing with currentOffset == 0 is faster still,
* so we preserve that case.
*/
if (cctx->currentOffset != 0 && tableType == byU32) {
DEBUGLOG(5, "LZ4_prepareTable: adding 64KB to currentOffset");
cctx->currentOffset += 64 KB;
}
/* Finally, clear history */
cctx->dictCtx = NULL;
cctx->dictionary = NULL;
cctx->dictSize = 0;
}
/** LZ4_compress_generic_validated() :
* inlined, to ensure branches are decided at compilation time.
* The following conditions are presumed already validated:
* - source != NULL
* - inputSize > 0
*/
LZ4_FORCE_INLINE int LZ4_compress_generic_validated(
LZ4_stream_t_internal* const cctx,
const char* const source,
char* const dest,
const int inputSize,
int* inputConsumed, /* only written when outputDirective == fillOutput */
const int maxOutputSize,
const limitedOutput_directive outputDirective,
const tableType_t tableType,
const dict_directive dictDirective,
const dictIssue_directive dictIssue,
const int acceleration)
{
int result;
const BYTE* ip = (const BYTE*)source;
U32 const startIndex = cctx->currentOffset;
const BYTE* base = (const BYTE*)source - startIndex;
const BYTE* lowLimit;
const LZ4_stream_t_internal* dictCtx = (const LZ4_stream_t_internal*) cctx->dictCtx;
const BYTE* const dictionary =
dictDirective == usingDictCtx ? dictCtx->dictionary : cctx->dictionary;
const U32 dictSize =
dictDirective == usingDictCtx ? dictCtx->dictSize : cctx->dictSize;
const U32 dictDelta =
(dictDirective == usingDictCtx) ? startIndex - dictCtx->currentOffset : 0; /* make indexes in dictCtx comparable with indexes in current context */
int const maybe_extMem = (dictDirective == usingExtDict) || (dictDirective == usingDictCtx);
U32 const prefixIdxLimit = startIndex - dictSize; /* used when dictDirective == dictSmall */
const BYTE* const dictEnd = dictionary ? dictionary + dictSize : dictionary;
const BYTE* anchor = (const BYTE*) source;
const BYTE* const iend = ip + inputSize;
const BYTE* const mflimitPlusOne = iend - MFLIMIT + 1;
const BYTE* const matchlimit = iend - LASTLITERALS;
/* the dictCtx currentOffset is indexed on the start of the dictionary,
* while a dictionary in the current context precedes the currentOffset */
const BYTE* dictBase = (dictionary == NULL) ? NULL :
(dictDirective == usingDictCtx) ?
dictionary + dictSize - dictCtx->currentOffset :
dictionary + dictSize - startIndex;
BYTE* op = (BYTE*) dest;
BYTE* const olimit = op + maxOutputSize;
U32 offset = 0;
U32 forwardH;
DEBUGLOG(5, "LZ4_compress_generic_validated: srcSize=%i, tableType=%u", inputSize, tableType);
assert(ip != NULL);
if (tableType == byU16) assert(inputSize<LZ4_64Klimit); /* Size too large (not within 64K limit) */
if (tableType == byPtr) assert(dictDirective==noDict); /* only supported use case with byPtr */
/* If init conditions are not met, we don't have to mark stream
* as having dirty context, since no action was taken yet */
if (outputDirective == fillOutput && maxOutputSize < 1) { return 0; } /* Impossible to store anything */
assert(acceleration >= 1);
lowLimit = (const BYTE*)source - (dictDirective == withPrefix64k ? dictSize : 0);
/* Update context state */
if (dictDirective == usingDictCtx) {
/* Subsequent linked blocks can't use the dictionary. */
/* Instead, they use the block we just compressed. */
cctx->dictCtx = NULL;
cctx->dictSize = (U32)inputSize;
} else {
cctx->dictSize += (U32)inputSize;
}
cctx->currentOffset += (U32)inputSize;
cctx->tableType = (U32)tableType;