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			237 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			237 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (c) Yann Collet, Facebook, Inc.
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|  * All rights reserved.
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|  *
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|  * This source code is licensed under both the BSD-style license (found in the
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|  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
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|  * in the COPYING file in the root directory of this source tree).
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|  * You may select, at your option, one of the above-listed licenses.
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|  */
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| 
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| 
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| /* zstd_decompress_internal:
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|  * objects and definitions shared within lib/decompress modules */
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| 
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|  #ifndef ZSTD_DECOMPRESS_INTERNAL_H
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|  #define ZSTD_DECOMPRESS_INTERNAL_H
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| 
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| 
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| /*-*******************************************************
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|  *  Dependencies
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|  *********************************************************/
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| #include "../common/mem.h"             /* BYTE, U16, U32 */
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| #include "../common/zstd_internal.h"   /* constants : MaxLL, MaxML, MaxOff, LLFSELog, etc. */
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| 
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| 
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| 
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| /*-*******************************************************
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|  *  Constants
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|  *********************************************************/
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| static UNUSED_ATTR const U32 LL_base[MaxLL+1] = {
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|                  0,    1,    2,     3,     4,     5,     6,      7,
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|                  8,    9,   10,    11,    12,    13,    14,     15,
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|                 16,   18,   20,    22,    24,    28,    32,     40,
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|                 48,   64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000,
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|                 0x2000, 0x4000, 0x8000, 0x10000 };
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| 
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| static UNUSED_ATTR const U32 OF_base[MaxOff+1] = {
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|                  0,        1,       1,       5,     0xD,     0x1D,     0x3D,     0x7D,
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|                  0xFD,   0x1FD,   0x3FD,   0x7FD,   0xFFD,   0x1FFD,   0x3FFD,   0x7FFD,
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|                  0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
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|                  0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
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| 
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| static UNUSED_ATTR const U8 OF_bits[MaxOff+1] = {
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|                      0,  1,  2,  3,  4,  5,  6,  7,
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|                      8,  9, 10, 11, 12, 13, 14, 15,
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|                     16, 17, 18, 19, 20, 21, 22, 23,
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|                     24, 25, 26, 27, 28, 29, 30, 31 };
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| 
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| static UNUSED_ATTR const U32 ML_base[MaxML+1] = {
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|                      3,  4,  5,    6,     7,     8,     9,    10,
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|                     11, 12, 13,   14,    15,    16,    17,    18,
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|                     19, 20, 21,   22,    23,    24,    25,    26,
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|                     27, 28, 29,   30,    31,    32,    33,    34,
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|                     35, 37, 39,   41,    43,    47,    51,    59,
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|                     67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803,
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|                     0x1003, 0x2003, 0x4003, 0x8003, 0x10003 };
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| 
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| 
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| /*-*******************************************************
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|  *  Decompression types
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|  *********************************************************/
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|  typedef struct {
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|      U32 fastMode;
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|      U32 tableLog;
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|  } ZSTD_seqSymbol_header;
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| 
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|  typedef struct {
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|      U16  nextState;
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|      BYTE nbAdditionalBits;
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|      BYTE nbBits;
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|      U32  baseValue;
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|  } ZSTD_seqSymbol;
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| 
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|  #define SEQSYMBOL_TABLE_SIZE(log)   (1 + (1 << (log)))
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| 
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| #define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE (sizeof(S16) * (MaxSeq + 1) + (1u << MaxFSELog) + sizeof(U64))
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| #define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32 ((ZSTD_BUILD_FSE_TABLE_WKSP_SIZE + sizeof(U32) - 1) / sizeof(U32))
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| 
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| typedef struct {
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|     ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)];    /* Note : Space reserved for FSE Tables */
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|     ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)];   /* is also used as temporary workspace while building hufTable during DDict creation */
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|     ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)];    /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */
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|     HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)];  /* can accommodate HUF_decompress4X */
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|     U32 rep[ZSTD_REP_NUM];
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|     U32 workspace[ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32];
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| } ZSTD_entropyDTables_t;
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| 
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| typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
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|                ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
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|                ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
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|                ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
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| 
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| typedef enum { zdss_init=0, zdss_loadHeader,
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|                zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
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| 
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| typedef enum {
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|     ZSTD_use_indefinitely = -1,  /* Use the dictionary indefinitely */
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|     ZSTD_dont_use = 0,           /* Do not use the dictionary (if one exists free it) */
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|     ZSTD_use_once = 1            /* Use the dictionary once and set to ZSTD_dont_use */
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| } ZSTD_dictUses_e;
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| 
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| /* Hashset for storing references to multiple ZSTD_DDict within ZSTD_DCtx */
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| typedef struct {
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|     const ZSTD_DDict** ddictPtrTable;
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|     size_t ddictPtrTableSize;
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|     size_t ddictPtrCount;
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| } ZSTD_DDictHashSet;
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| 
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| #ifndef ZSTD_DECODER_INTERNAL_BUFFER
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| #  define ZSTD_DECODER_INTERNAL_BUFFER  (1 << 16)
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| #endif
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| 
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| #define ZSTD_LBMIN 64
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| #define ZSTD_LBMAX (128 << 10)
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| 
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| /* extra buffer, compensates when dst is not large enough to store litBuffer */
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| #define ZSTD_LITBUFFEREXTRASIZE  BOUNDED(ZSTD_LBMIN, ZSTD_DECODER_INTERNAL_BUFFER, ZSTD_LBMAX)
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| 
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| typedef enum {
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|     ZSTD_not_in_dst = 0,  /* Stored entirely within litExtraBuffer */
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|     ZSTD_in_dst = 1,           /* Stored entirely within dst (in memory after current output write) */
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|     ZSTD_split = 2            /* Split between litExtraBuffer and dst */
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| } ZSTD_litLocation_e;
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| 
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| struct ZSTD_DCtx_s
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| {
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|     const ZSTD_seqSymbol* LLTptr;
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|     const ZSTD_seqSymbol* MLTptr;
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|     const ZSTD_seqSymbol* OFTptr;
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|     const HUF_DTable* HUFptr;
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|     ZSTD_entropyDTables_t entropy;
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|     U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];   /* space needed when building huffman tables */
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|     const void* previousDstEnd;   /* detect continuity */
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|     const void* prefixStart;      /* start of current segment */
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|     const void* virtualStart;     /* virtual start of previous segment if it was just before current one */
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|     const void* dictEnd;          /* end of previous segment */
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|     size_t expected;
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|     ZSTD_frameHeader fParams;
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|     U64 processedCSize;
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|     U64 decodedSize;
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|     blockType_e bType;            /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
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|     ZSTD_dStage stage;
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|     U32 litEntropy;
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|     U32 fseEntropy;
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|     XXH64_state_t xxhState;
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|     size_t headerSize;
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|     ZSTD_format_e format;
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|     ZSTD_forceIgnoreChecksum_e forceIgnoreChecksum;   /* User specified: if == 1, will ignore checksums in compressed frame. Default == 0 */
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|     U32 validateChecksum;         /* if == 1, will validate checksum. Is == 1 if (fParams.checksumFlag == 1) and (forceIgnoreChecksum == 0). */
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|     const BYTE* litPtr;
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|     ZSTD_customMem customMem;
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|     size_t litSize;
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|     size_t rleSize;
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|     size_t staticSize;
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| #if DYNAMIC_BMI2 != 0
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|     int bmi2;                     /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
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| #endif
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| 
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|     /* dictionary */
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|     ZSTD_DDict* ddictLocal;
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|     const ZSTD_DDict* ddict;     /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
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|     U32 dictID;
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|     int ddictIsCold;             /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
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|     ZSTD_dictUses_e dictUses;
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|     ZSTD_DDictHashSet* ddictSet;                    /* Hash set for multiple ddicts */
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|     ZSTD_refMultipleDDicts_e refMultipleDDicts;     /* User specified: if == 1, will allow references to multiple DDicts. Default == 0 (disabled) */
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| 
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|     /* streaming */
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|     ZSTD_dStreamStage streamStage;
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|     char*  inBuff;
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|     size_t inBuffSize;
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|     size_t inPos;
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|     size_t maxWindowSize;
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|     char*  outBuff;
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|     size_t outBuffSize;
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|     size_t outStart;
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|     size_t outEnd;
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|     size_t lhSize;
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| #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
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|     void* legacyContext;
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|     U32 previousLegacyVersion;
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|     U32 legacyVersion;
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| #endif
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|     U32 hostageByte;
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|     int noForwardProgress;
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|     ZSTD_bufferMode_e outBufferMode;
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|     ZSTD_outBuffer expectedOutBuffer;
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| 
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|     /* workspace */
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|     BYTE* litBuffer;
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|     const BYTE* litBufferEnd;
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|     ZSTD_litLocation_e litBufferLocation;
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|     BYTE litExtraBuffer[ZSTD_LITBUFFEREXTRASIZE + WILDCOPY_OVERLENGTH]; /* literal buffer can be split between storage within dst and within this scratch buffer */
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|     BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
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| 
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|     size_t oversizedDuration;
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| 
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| #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
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|     void const* dictContentBeginForFuzzing;
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|     void const* dictContentEndForFuzzing;
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| #endif
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| 
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|     /* Tracing */
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| #if ZSTD_TRACE
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|     ZSTD_TraceCtx traceCtx;
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| #endif
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| };  /* typedef'd to ZSTD_DCtx within "zstd.h" */
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| 
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| MEM_STATIC int ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s *dctx) {
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| #if DYNAMIC_BMI2 != 0
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| 	return dctx->bmi2;
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| #else
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|     (void)dctx;
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| 	return 0;
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| #endif
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| }
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| 
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| /*-*******************************************************
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|  *  Shared internal functions
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|  *********************************************************/
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| 
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| /*! ZSTD_loadDEntropy() :
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|  *  dict : must point at beginning of a valid zstd dictionary.
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|  * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */
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| size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
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|                    const void* const dict, size_t const dictSize);
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| 
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| /*! ZSTD_checkContinuity() :
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|  *  check if next `dst` follows previous position, where decompression ended.
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|  *  If yes, do nothing (continue on current segment).
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|  *  If not, classify previous segment as "external dictionary", and start a new segment.
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|  *  This function cannot fail. */
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| void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize);
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| 
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| 
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| #endif /* ZSTD_DECOMPRESS_INTERNAL_H */
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