286 lines
14 KiB
C++
286 lines
14 KiB
C++
/* ******************************************************************
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* huff0 huffman codec,
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* part of Finite State Entropy library
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* You can contact the author at :
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* - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
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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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#if defined (__cplusplus)
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extern "C" {
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#endif
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#ifndef HUF_H_298734234
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#define HUF_H_298734234
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/* *** Dependencies *** */
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#include "zstd_deps.h" /* size_t */
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#include "mem.h" /* U32 */
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#define FSE_STATIC_LINKING_ONLY
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#include "fse.h"
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/* *** Tool functions *** */
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#define HUF_BLOCKSIZE_MAX (128 * 1024) /**< maximum input size for a single block compressed with HUF_compress */
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size_t HUF_compressBound(size_t size); /**< maximum compressed size (worst case) */
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/* Error Management */
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unsigned HUF_isError(size_t code); /**< tells if a return value is an error code */
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const char* HUF_getErrorName(size_t code); /**< provides error code string (useful for debugging) */
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#define HUF_WORKSPACE_SIZE ((8 << 10) + 512 /* sorting scratch space */)
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#define HUF_WORKSPACE_SIZE_U64 (HUF_WORKSPACE_SIZE / sizeof(U64))
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/* *** Constants *** */
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#define HUF_TABLELOG_MAX 12 /* max runtime value of tableLog (due to static allocation); can be modified up to HUF_TABLELOG_ABSOLUTEMAX */
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#define HUF_TABLELOG_DEFAULT 11 /* default tableLog value when none specified */
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#define HUF_SYMBOLVALUE_MAX 255
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#define HUF_TABLELOG_ABSOLUTEMAX 12 /* absolute limit of HUF_MAX_TABLELOG. Beyond that value, code does not work */
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#if (HUF_TABLELOG_MAX > HUF_TABLELOG_ABSOLUTEMAX)
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# error "HUF_TABLELOG_MAX is too large !"
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#endif
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/* ****************************************
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* Static allocation
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******************************************/
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/* HUF buffer bounds */
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#define HUF_CTABLEBOUND 129
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#define HUF_BLOCKBOUND(size) (size + (size>>8) + 8) /* only true when incompressible is pre-filtered with fast heuristic */
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#define HUF_COMPRESSBOUND(size) (HUF_CTABLEBOUND + HUF_BLOCKBOUND(size)) /* Macro version, useful for static allocation */
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/* static allocation of HUF's Compression Table */
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/* this is a private definition, just exposed for allocation and strict aliasing purpose. never EVER access its members directly */
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typedef size_t HUF_CElt; /* consider it an incomplete type */
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#define HUF_CTABLE_SIZE_ST(maxSymbolValue) ((maxSymbolValue)+2) /* Use tables of size_t, for proper alignment */
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#define HUF_CTABLE_SIZE(maxSymbolValue) (HUF_CTABLE_SIZE_ST(maxSymbolValue) * sizeof(size_t))
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#define HUF_CREATE_STATIC_CTABLE(name, maxSymbolValue) \
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HUF_CElt name[HUF_CTABLE_SIZE_ST(maxSymbolValue)] /* no final ; */
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/* static allocation of HUF's DTable */
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typedef U32 HUF_DTable;
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#define HUF_DTABLE_SIZE(maxTableLog) (1 + (1<<(maxTableLog)))
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#define HUF_CREATE_STATIC_DTABLEX1(DTable, maxTableLog) \
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HUF_DTable DTable[HUF_DTABLE_SIZE((maxTableLog)-1)] = { ((U32)((maxTableLog)-1) * 0x01000001) }
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#define HUF_CREATE_STATIC_DTABLEX2(DTable, maxTableLog) \
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HUF_DTable DTable[HUF_DTABLE_SIZE(maxTableLog)] = { ((U32)(maxTableLog) * 0x01000001) }
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/* ****************************************
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* Advanced decompression functions
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******************************************/
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/**
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* Huffman flags bitset.
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* For all flags, 0 is the default value.
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*/
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typedef enum {
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/**
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* If compiled with DYNAMIC_BMI2: Set flag only if the CPU supports BMI2 at runtime.
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* Otherwise: Ignored.
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*/
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HUF_flags_bmi2 = (1 << 0),
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/**
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* If set: Test possible table depths to find the one that produces the smallest header + encoded size.
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* If unset: Use heuristic to find the table depth.
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*/
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HUF_flags_optimalDepth = (1 << 1),
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/**
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* If set: If the previous table can encode the input, always reuse the previous table.
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* If unset: If the previous table can encode the input, reuse the previous table if it results in a smaller output.
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*/
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HUF_flags_preferRepeat = (1 << 2),
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/**
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* If set: Sample the input and check if the sample is uncompressible, if it is then don't attempt to compress.
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* If unset: Always histogram the entire input.
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*/
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HUF_flags_suspectUncompressible = (1 << 3),
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/**
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* If set: Don't use assembly implementations
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* If unset: Allow using assembly implementations
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*/
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HUF_flags_disableAsm = (1 << 4),
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/**
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* If set: Don't use the fast decoding loop, always use the fallback decoding loop.
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* If unset: Use the fast decoding loop when possible.
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*/
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HUF_flags_disableFast = (1 << 5)
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} HUF_flags_e;
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/* ****************************************
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* HUF detailed API
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* ****************************************/
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#define HUF_OPTIMAL_DEPTH_THRESHOLD ZSTD_btultra
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/*! HUF_compress() does the following:
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* 1. count symbol occurrence from source[] into table count[] using FSE_count() (exposed within "fse.h")
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* 2. (optional) refine tableLog using HUF_optimalTableLog()
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* 3. build Huffman table from count using HUF_buildCTable()
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* 4. save Huffman table to memory buffer using HUF_writeCTable()
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* 5. encode the data stream using HUF_compress4X_usingCTable()
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*
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* The following API allows targeting specific sub-functions for advanced tasks.
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* For example, it's possible to compress several blocks using the same 'CTable',
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* or to save and regenerate 'CTable' using external methods.
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*/
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unsigned HUF_minTableLog(unsigned symbolCardinality);
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unsigned HUF_cardinality(const unsigned* count, unsigned maxSymbolValue);
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unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue, void* workSpace,
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size_t wkspSize, HUF_CElt* table, const unsigned* count, int flags); /* table is used as scratch space for building and testing tables, not a return value */
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size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize, const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog, void* workspace, size_t workspaceSize);
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size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags);
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size_t HUF_estimateCompressedSize(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue);
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int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue);
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typedef enum {
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HUF_repeat_none, /**< Cannot use the previous table */
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HUF_repeat_check, /**< Can use the previous table but it must be checked. Note : The previous table must have been constructed by HUF_compress{1, 4}X_repeat */
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HUF_repeat_valid /**< Can use the previous table and it is assumed to be valid */
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} HUF_repeat;
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/** HUF_compress4X_repeat() :
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* Same as HUF_compress4X_wksp(), but considers using hufTable if *repeat != HUF_repeat_none.
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* If it uses hufTable it does not modify hufTable or repeat.
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* If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to the table used.
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* If preferRepeat then the old table will always be used if valid.
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* If suspectUncompressible then some sampling checks will be run to potentially skip huffman coding */
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size_t HUF_compress4X_repeat(void* dst, size_t dstSize,
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const void* src, size_t srcSize,
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unsigned maxSymbolValue, unsigned tableLog,
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void* workSpace, size_t wkspSize, /**< `workSpace` must be aligned on 4-bytes boundaries, `wkspSize` must be >= HUF_WORKSPACE_SIZE */
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HUF_CElt* hufTable, HUF_repeat* repeat, int flags);
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/** HUF_buildCTable_wksp() :
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* Same as HUF_buildCTable(), but using externally allocated scratch buffer.
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* `workSpace` must be aligned on 4-bytes boundaries, and its size must be >= HUF_CTABLE_WORKSPACE_SIZE.
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*/
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#define HUF_CTABLE_WORKSPACE_SIZE_U32 ((4 * (HUF_SYMBOLVALUE_MAX + 1)) + 192)
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#define HUF_CTABLE_WORKSPACE_SIZE (HUF_CTABLE_WORKSPACE_SIZE_U32 * sizeof(unsigned))
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size_t HUF_buildCTable_wksp (HUF_CElt* tree,
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const unsigned* count, U32 maxSymbolValue, U32 maxNbBits,
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void* workSpace, size_t wkspSize);
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/*! HUF_readStats() :
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* Read compact Huffman tree, saved by HUF_writeCTable().
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* `huffWeight` is destination buffer.
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* @return : size read from `src` , or an error Code .
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* Note : Needed by HUF_readCTable() and HUF_readDTableXn() . */
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size_t HUF_readStats(BYTE* huffWeight, size_t hwSize,
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U32* rankStats, U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize);
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/*! HUF_readStats_wksp() :
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* Same as HUF_readStats() but takes an external workspace which must be
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* 4-byte aligned and its size must be >= HUF_READ_STATS_WORKSPACE_SIZE.
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* If the CPU has BMI2 support, pass bmi2=1, otherwise pass bmi2=0.
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*/
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#define HUF_READ_STATS_WORKSPACE_SIZE_U32 FSE_DECOMPRESS_WKSP_SIZE_U32(6, HUF_TABLELOG_MAX-1)
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#define HUF_READ_STATS_WORKSPACE_SIZE (HUF_READ_STATS_WORKSPACE_SIZE_U32 * sizeof(unsigned))
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size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize,
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U32* rankStats, U32* nbSymbolsPtr, U32* tableLogPtr,
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const void* src, size_t srcSize,
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void* workspace, size_t wkspSize,
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int flags);
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/** HUF_readCTable() :
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* Loading a CTable saved with HUF_writeCTable() */
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size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned *hasZeroWeights);
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/** HUF_getNbBitsFromCTable() :
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* Read nbBits from CTable symbolTable, for symbol `symbolValue` presumed <= HUF_SYMBOLVALUE_MAX
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* Note 1 : If symbolValue > HUF_readCTableHeader(symbolTable).maxSymbolValue, returns 0
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* Note 2 : is not inlined, as HUF_CElt definition is private
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*/
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U32 HUF_getNbBitsFromCTable(const HUF_CElt* symbolTable, U32 symbolValue);
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typedef struct {
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BYTE tableLog;
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BYTE maxSymbolValue;
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BYTE unused[sizeof(size_t) - 2];
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} HUF_CTableHeader;
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/** HUF_readCTableHeader() :
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* @returns The header from the CTable specifying the tableLog and the maxSymbolValue.
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*/
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HUF_CTableHeader HUF_readCTableHeader(HUF_CElt const* ctable);
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/*
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* HUF_decompress() does the following:
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* 1. select the decompression algorithm (X1, X2) based on pre-computed heuristics
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* 2. build Huffman table from save, using HUF_readDTableX?()
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* 3. decode 1 or 4 segments in parallel using HUF_decompress?X?_usingDTable()
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*/
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/** HUF_selectDecoder() :
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* Tells which decoder is likely to decode faster,
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* based on a set of pre-computed metrics.
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* @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
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* Assumption : 0 < dstSize <= 128 KB */
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U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize);
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/**
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* The minimum workspace size for the `workSpace` used in
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* HUF_readDTableX1_wksp() and HUF_readDTableX2_wksp().
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*
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* The space used depends on HUF_TABLELOG_MAX, ranging from ~1500 bytes when
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* HUF_TABLE_LOG_MAX=12 to ~1850 bytes when HUF_TABLE_LOG_MAX=15.
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* Buffer overflow errors may potentially occur if code modifications result in
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* a required workspace size greater than that specified in the following
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* macro.
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*/
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#define HUF_DECOMPRESS_WORKSPACE_SIZE ((2 << 10) + (1 << 9))
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#define HUF_DECOMPRESS_WORKSPACE_SIZE_U32 (HUF_DECOMPRESS_WORKSPACE_SIZE / sizeof(U32))
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/* ====================== */
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/* single stream variants */
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/* ====================== */
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size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags);
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/** HUF_compress1X_repeat() :
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* Same as HUF_compress1X_wksp(), but considers using hufTable if *repeat != HUF_repeat_none.
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* If it uses hufTable it does not modify hufTable or repeat.
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* If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to the table used.
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* If preferRepeat then the old table will always be used if valid.
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* If suspectUncompressible then some sampling checks will be run to potentially skip huffman coding */
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size_t HUF_compress1X_repeat(void* dst, size_t dstSize,
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const void* src, size_t srcSize,
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unsigned maxSymbolValue, unsigned tableLog,
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void* workSpace, size_t wkspSize, /**< `workSpace` must be aligned on 4-bytes boundaries, `wkspSize` must be >= HUF_WORKSPACE_SIZE */
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HUF_CElt* hufTable, HUF_repeat* repeat, int flags);
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size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags);
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#ifndef HUF_FORCE_DECOMPRESS_X1
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size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags); /**< double-symbols decoder */
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#endif
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/* BMI2 variants.
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* If the CPU has BMI2 support, pass bmi2=1, otherwise pass bmi2=0.
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*/
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size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int flags);
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#ifndef HUF_FORCE_DECOMPRESS_X2
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size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags);
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#endif
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size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int flags);
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size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags);
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#ifndef HUF_FORCE_DECOMPRESS_X2
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size_t HUF_readDTableX1_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int flags);
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#endif
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#ifndef HUF_FORCE_DECOMPRESS_X1
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size_t HUF_readDTableX2_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int flags);
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#endif
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#endif /* HUF_H_298734234 */
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#if defined (__cplusplus)
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}
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#endif
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