cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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huf_decompress.c (49265B)


      1/* ******************************************************************
      2 * huff0 huffman decoder,
      3 * part of Finite State Entropy library
      4 * Copyright (c) Yann Collet, Facebook, Inc.
      5 *
      6 *  You can contact the author at :
      7 *  - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
      8 *
      9 * This source code is licensed under both the BSD-style license (found in the
     10 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
     11 * in the COPYING file in the root directory of this source tree).
     12 * You may select, at your option, one of the above-listed licenses.
     13****************************************************************** */
     14
     15/* **************************************************************
     16*  Dependencies
     17****************************************************************/
     18#include "../common/zstd_deps.h"  /* ZSTD_memcpy, ZSTD_memset */
     19#include "../common/compiler.h"
     20#include "../common/bitstream.h"  /* BIT_* */
     21#include "../common/fse.h"        /* to compress headers */
     22#define HUF_STATIC_LINKING_ONLY
     23#include "../common/huf.h"
     24#include "../common/error_private.h"
     25
     26/* **************************************************************
     27*  Macros
     28****************************************************************/
     29
     30/* These two optional macros force the use one way or another of the two
     31 * Huffman decompression implementations. You can't force in both directions
     32 * at the same time.
     33 */
     34#if defined(HUF_FORCE_DECOMPRESS_X1) && \
     35    defined(HUF_FORCE_DECOMPRESS_X2)
     36#error "Cannot force the use of the X1 and X2 decoders at the same time!"
     37#endif
     38
     39
     40/* **************************************************************
     41*  Error Management
     42****************************************************************/
     43#define HUF_isError ERR_isError
     44
     45
     46/* **************************************************************
     47*  Byte alignment for workSpace management
     48****************************************************************/
     49#define HUF_ALIGN(x, a)         HUF_ALIGN_MASK((x), (a) - 1)
     50#define HUF_ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
     51
     52
     53/* **************************************************************
     54*  BMI2 Variant Wrappers
     55****************************************************************/
     56#if DYNAMIC_BMI2
     57
     58#define HUF_DGEN(fn)                                                        \
     59                                                                            \
     60    static size_t fn##_default(                                             \
     61                  void* dst,  size_t dstSize,                               \
     62            const void* cSrc, size_t cSrcSize,                              \
     63            const HUF_DTable* DTable)                                       \
     64    {                                                                       \
     65        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
     66    }                                                                       \
     67                                                                            \
     68    static TARGET_ATTRIBUTE("bmi2") size_t fn##_bmi2(                       \
     69                  void* dst,  size_t dstSize,                               \
     70            const void* cSrc, size_t cSrcSize,                              \
     71            const HUF_DTable* DTable)                                       \
     72    {                                                                       \
     73        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
     74    }                                                                       \
     75                                                                            \
     76    static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
     77                     size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
     78    {                                                                       \
     79        if (bmi2) {                                                         \
     80            return fn##_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);         \
     81        }                                                                   \
     82        return fn##_default(dst, dstSize, cSrc, cSrcSize, DTable);          \
     83    }
     84
     85#else
     86
     87#define HUF_DGEN(fn)                                                        \
     88    static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
     89                     size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
     90    {                                                                       \
     91        (void)bmi2;                                                         \
     92        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
     93    }
     94
     95#endif
     96
     97
     98/*-***************************/
     99/*  generic DTableDesc       */
    100/*-***************************/
    101typedef struct { BYTE maxTableLog; BYTE tableType; BYTE tableLog; BYTE reserved; } DTableDesc;
    102
    103static DTableDesc HUF_getDTableDesc(const HUF_DTable* table)
    104{
    105    DTableDesc dtd;
    106    ZSTD_memcpy(&dtd, table, sizeof(dtd));
    107    return dtd;
    108}
    109
    110
    111#ifndef HUF_FORCE_DECOMPRESS_X2
    112
    113/*-***************************/
    114/*  single-symbol decoding   */
    115/*-***************************/
    116typedef struct { BYTE byte; BYTE nbBits; } HUF_DEltX1;   /* single-symbol decoding */
    117
    118/*
    119 * Packs 4 HUF_DEltX1 structs into a U64. This is used to lay down 4 entries at
    120 * a time.
    121 */
    122static U64 HUF_DEltX1_set4(BYTE symbol, BYTE nbBits) {
    123    U64 D4;
    124    if (MEM_isLittleEndian()) {
    125        D4 = symbol + (nbBits << 8);
    126    } else {
    127        D4 = (symbol << 8) + nbBits;
    128    }
    129    D4 *= 0x0001000100010001ULL;
    130    return D4;
    131}
    132
    133typedef struct {
    134        U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1];
    135        U32 rankStart[HUF_TABLELOG_ABSOLUTEMAX + 1];
    136        U32 statsWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
    137        BYTE symbols[HUF_SYMBOLVALUE_MAX + 1];
    138        BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1];
    139} HUF_ReadDTableX1_Workspace;
    140
    141
    142size_t HUF_readDTableX1_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize)
    143{
    144    return HUF_readDTableX1_wksp_bmi2(DTable, src, srcSize, workSpace, wkspSize, /* bmi2 */ 0);
    145}
    146
    147size_t HUF_readDTableX1_wksp_bmi2(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int bmi2)
    148{
    149    U32 tableLog = 0;
    150    U32 nbSymbols = 0;
    151    size_t iSize;
    152    void* const dtPtr = DTable + 1;
    153    HUF_DEltX1* const dt = (HUF_DEltX1*)dtPtr;
    154    HUF_ReadDTableX1_Workspace* wksp = (HUF_ReadDTableX1_Workspace*)workSpace;
    155
    156    DEBUG_STATIC_ASSERT(HUF_DECOMPRESS_WORKSPACE_SIZE >= sizeof(*wksp));
    157    if (sizeof(*wksp) > wkspSize) return ERROR(tableLog_tooLarge);
    158
    159    DEBUG_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUF_DTable));
    160    /* ZSTD_memset(huffWeight, 0, sizeof(huffWeight)); */   /* is not necessary, even though some analyzer complain ... */
    161
    162    iSize = HUF_readStats_wksp(wksp->huffWeight, HUF_SYMBOLVALUE_MAX + 1, wksp->rankVal, &nbSymbols, &tableLog, src, srcSize, wksp->statsWksp, sizeof(wksp->statsWksp), bmi2);
    163    if (HUF_isError(iSize)) return iSize;
    164
    165    /* Table header */
    166    {   DTableDesc dtd = HUF_getDTableDesc(DTable);
    167        if (tableLog > (U32)(dtd.maxTableLog+1)) return ERROR(tableLog_tooLarge);   /* DTable too small, Huffman tree cannot fit in */
    168        dtd.tableType = 0;
    169        dtd.tableLog = (BYTE)tableLog;
    170        ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
    171    }
    172
    173    /* Compute symbols and rankStart given rankVal:
    174     *
    175     * rankVal already contains the number of values of each weight.
    176     *
    177     * symbols contains the symbols ordered by weight. First are the rankVal[0]
    178     * weight 0 symbols, followed by the rankVal[1] weight 1 symbols, and so on.
    179     * symbols[0] is filled (but unused) to avoid a branch.
    180     *
    181     * rankStart contains the offset where each rank belongs in the DTable.
    182     * rankStart[0] is not filled because there are no entries in the table for
    183     * weight 0.
    184     */
    185    {
    186        int n;
    187        int nextRankStart = 0;
    188        int const unroll = 4;
    189        int const nLimit = (int)nbSymbols - unroll + 1;
    190        for (n=0; n<(int)tableLog+1; n++) {
    191            U32 const curr = nextRankStart;
    192            nextRankStart += wksp->rankVal[n];
    193            wksp->rankStart[n] = curr;
    194        }
    195        for (n=0; n < nLimit; n += unroll) {
    196            int u;
    197            for (u=0; u < unroll; ++u) {
    198                size_t const w = wksp->huffWeight[n+u];
    199                wksp->symbols[wksp->rankStart[w]++] = (BYTE)(n+u);
    200            }
    201        }
    202        for (; n < (int)nbSymbols; ++n) {
    203            size_t const w = wksp->huffWeight[n];
    204            wksp->symbols[wksp->rankStart[w]++] = (BYTE)n;
    205        }
    206    }
    207
    208    /* fill DTable
    209     * We fill all entries of each weight in order.
    210     * That way length is a constant for each iteration of the outter loop.
    211     * We can switch based on the length to a different inner loop which is
    212     * optimized for that particular case.
    213     */
    214    {
    215        U32 w;
    216        int symbol=wksp->rankVal[0];
    217        int rankStart=0;
    218        for (w=1; w<tableLog+1; ++w) {
    219            int const symbolCount = wksp->rankVal[w];
    220            int const length = (1 << w) >> 1;
    221            int uStart = rankStart;
    222            BYTE const nbBits = (BYTE)(tableLog + 1 - w);
    223            int s;
    224            int u;
    225            switch (length) {
    226            case 1:
    227                for (s=0; s<symbolCount; ++s) {
    228                    HUF_DEltX1 D;
    229                    D.byte = wksp->symbols[symbol + s];
    230                    D.nbBits = nbBits;
    231                    dt[uStart] = D;
    232                    uStart += 1;
    233                }
    234                break;
    235            case 2:
    236                for (s=0; s<symbolCount; ++s) {
    237                    HUF_DEltX1 D;
    238                    D.byte = wksp->symbols[symbol + s];
    239                    D.nbBits = nbBits;
    240                    dt[uStart+0] = D;
    241                    dt[uStart+1] = D;
    242                    uStart += 2;
    243                }
    244                break;
    245            case 4:
    246                for (s=0; s<symbolCount; ++s) {
    247                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
    248                    MEM_write64(dt + uStart, D4);
    249                    uStart += 4;
    250                }
    251                break;
    252            case 8:
    253                for (s=0; s<symbolCount; ++s) {
    254                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
    255                    MEM_write64(dt + uStart, D4);
    256                    MEM_write64(dt + uStart + 4, D4);
    257                    uStart += 8;
    258                }
    259                break;
    260            default:
    261                for (s=0; s<symbolCount; ++s) {
    262                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
    263                    for (u=0; u < length; u += 16) {
    264                        MEM_write64(dt + uStart + u + 0, D4);
    265                        MEM_write64(dt + uStart + u + 4, D4);
    266                        MEM_write64(dt + uStart + u + 8, D4);
    267                        MEM_write64(dt + uStart + u + 12, D4);
    268                    }
    269                    assert(u == length);
    270                    uStart += length;
    271                }
    272                break;
    273            }
    274            symbol += symbolCount;
    275            rankStart += symbolCount * length;
    276        }
    277    }
    278    return iSize;
    279}
    280
    281FORCE_INLINE_TEMPLATE BYTE
    282HUF_decodeSymbolX1(BIT_DStream_t* Dstream, const HUF_DEltX1* dt, const U32 dtLog)
    283{
    284    size_t const val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
    285    BYTE const c = dt[val].byte;
    286    BIT_skipBits(Dstream, dt[val].nbBits);
    287    return c;
    288}
    289
    290#define HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr) \
    291    *ptr++ = HUF_decodeSymbolX1(DStreamPtr, dt, dtLog)
    292
    293#define HUF_DECODE_SYMBOLX1_1(ptr, DStreamPtr)  \
    294    if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
    295        HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr)
    296
    297#define HUF_DECODE_SYMBOLX1_2(ptr, DStreamPtr) \
    298    if (MEM_64bits()) \
    299        HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr)
    300
    301HINT_INLINE size_t
    302HUF_decodeStreamX1(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, const HUF_DEltX1* const dt, const U32 dtLog)
    303{
    304    BYTE* const pStart = p;
    305
    306    /* up to 4 symbols at a time */
    307    while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-3)) {
    308        HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
    309        HUF_DECODE_SYMBOLX1_1(p, bitDPtr);
    310        HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
    311        HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
    312    }
    313
    314    /* [0-3] symbols remaining */
    315    if (MEM_32bits())
    316        while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd))
    317            HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
    318
    319    /* no more data to retrieve from bitstream, no need to reload */
    320    while (p < pEnd)
    321        HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
    322
    323    return pEnd-pStart;
    324}
    325
    326FORCE_INLINE_TEMPLATE size_t
    327HUF_decompress1X1_usingDTable_internal_body(
    328          void* dst,  size_t dstSize,
    329    const void* cSrc, size_t cSrcSize,
    330    const HUF_DTable* DTable)
    331{
    332    BYTE* op = (BYTE*)dst;
    333    BYTE* const oend = op + dstSize;
    334    const void* dtPtr = DTable + 1;
    335    const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
    336    BIT_DStream_t bitD;
    337    DTableDesc const dtd = HUF_getDTableDesc(DTable);
    338    U32 const dtLog = dtd.tableLog;
    339
    340    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
    341
    342    HUF_decodeStreamX1(op, &bitD, oend, dt, dtLog);
    343
    344    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
    345
    346    return dstSize;
    347}
    348
    349FORCE_INLINE_TEMPLATE size_t
    350HUF_decompress4X1_usingDTable_internal_body(
    351          void* dst,  size_t dstSize,
    352    const void* cSrc, size_t cSrcSize,
    353    const HUF_DTable* DTable)
    354{
    355    /* Check */
    356    if (cSrcSize < 10) return ERROR(corruption_detected);  /* strict minimum : jump table + 1 byte per stream */
    357
    358    {   const BYTE* const istart = (const BYTE*) cSrc;
    359        BYTE* const ostart = (BYTE*) dst;
    360        BYTE* const oend = ostart + dstSize;
    361        BYTE* const olimit = oend - 3;
    362        const void* const dtPtr = DTable + 1;
    363        const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
    364
    365        /* Init */
    366        BIT_DStream_t bitD1;
    367        BIT_DStream_t bitD2;
    368        BIT_DStream_t bitD3;
    369        BIT_DStream_t bitD4;
    370        size_t const length1 = MEM_readLE16(istart);
    371        size_t const length2 = MEM_readLE16(istart+2);
    372        size_t const length3 = MEM_readLE16(istart+4);
    373        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
    374        const BYTE* const istart1 = istart + 6;  /* jumpTable */
    375        const BYTE* const istart2 = istart1 + length1;
    376        const BYTE* const istart3 = istart2 + length2;
    377        const BYTE* const istart4 = istart3 + length3;
    378        const size_t segmentSize = (dstSize+3) / 4;
    379        BYTE* const opStart2 = ostart + segmentSize;
    380        BYTE* const opStart3 = opStart2 + segmentSize;
    381        BYTE* const opStart4 = opStart3 + segmentSize;
    382        BYTE* op1 = ostart;
    383        BYTE* op2 = opStart2;
    384        BYTE* op3 = opStart3;
    385        BYTE* op4 = opStart4;
    386        DTableDesc const dtd = HUF_getDTableDesc(DTable);
    387        U32 const dtLog = dtd.tableLog;
    388        U32 endSignal = 1;
    389
    390        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
    391        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
    392        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
    393        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
    394        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
    395
    396        /* up to 16 symbols per loop (4 symbols per stream) in 64-bit mode */
    397        for ( ; (endSignal) & (op4 < olimit) ; ) {
    398            HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
    399            HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
    400            HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
    401            HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
    402            HUF_DECODE_SYMBOLX1_1(op1, &bitD1);
    403            HUF_DECODE_SYMBOLX1_1(op2, &bitD2);
    404            HUF_DECODE_SYMBOLX1_1(op3, &bitD3);
    405            HUF_DECODE_SYMBOLX1_1(op4, &bitD4);
    406            HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
    407            HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
    408            HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
    409            HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
    410            HUF_DECODE_SYMBOLX1_0(op1, &bitD1);
    411            HUF_DECODE_SYMBOLX1_0(op2, &bitD2);
    412            HUF_DECODE_SYMBOLX1_0(op3, &bitD3);
    413            HUF_DECODE_SYMBOLX1_0(op4, &bitD4);
    414            endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
    415            endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
    416            endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
    417            endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
    418        }
    419
    420        /* check corruption */
    421        /* note : should not be necessary : op# advance in lock step, and we control op4.
    422         *        but curiously, binary generated by gcc 7.2 & 7.3 with -mbmi2 runs faster when >=1 test is present */
    423        if (op1 > opStart2) return ERROR(corruption_detected);
    424        if (op2 > opStart3) return ERROR(corruption_detected);
    425        if (op3 > opStart4) return ERROR(corruption_detected);
    426        /* note : op4 supposed already verified within main loop */
    427
    428        /* finish bitStreams one by one */
    429        HUF_decodeStreamX1(op1, &bitD1, opStart2, dt, dtLog);
    430        HUF_decodeStreamX1(op2, &bitD2, opStart3, dt, dtLog);
    431        HUF_decodeStreamX1(op3, &bitD3, opStart4, dt, dtLog);
    432        HUF_decodeStreamX1(op4, &bitD4, oend,     dt, dtLog);
    433
    434        /* check */
    435        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
    436          if (!endCheck) return ERROR(corruption_detected); }
    437
    438        /* decoded size */
    439        return dstSize;
    440    }
    441}
    442
    443
    444typedef size_t (*HUF_decompress_usingDTable_t)(void *dst, size_t dstSize,
    445                                               const void *cSrc,
    446                                               size_t cSrcSize,
    447                                               const HUF_DTable *DTable);
    448
    449HUF_DGEN(HUF_decompress1X1_usingDTable_internal)
    450HUF_DGEN(HUF_decompress4X1_usingDTable_internal)
    451
    452
    453
    454size_t HUF_decompress1X1_usingDTable(
    455          void* dst,  size_t dstSize,
    456    const void* cSrc, size_t cSrcSize,
    457    const HUF_DTable* DTable)
    458{
    459    DTableDesc dtd = HUF_getDTableDesc(DTable);
    460    if (dtd.tableType != 0) return ERROR(GENERIC);
    461    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
    462}
    463
    464size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
    465                                   const void* cSrc, size_t cSrcSize,
    466                                   void* workSpace, size_t wkspSize)
    467{
    468    const BYTE* ip = (const BYTE*) cSrc;
    469
    470    size_t const hSize = HUF_readDTableX1_wksp(DCtx, cSrc, cSrcSize, workSpace, wkspSize);
    471    if (HUF_isError(hSize)) return hSize;
    472    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
    473    ip += hSize; cSrcSize -= hSize;
    474
    475    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
    476}
    477
    478
    479size_t HUF_decompress4X1_usingDTable(
    480          void* dst,  size_t dstSize,
    481    const void* cSrc, size_t cSrcSize,
    482    const HUF_DTable* DTable)
    483{
    484    DTableDesc dtd = HUF_getDTableDesc(DTable);
    485    if (dtd.tableType != 0) return ERROR(GENERIC);
    486    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
    487}
    488
    489static size_t HUF_decompress4X1_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
    490                                   const void* cSrc, size_t cSrcSize,
    491                                   void* workSpace, size_t wkspSize, int bmi2)
    492{
    493    const BYTE* ip = (const BYTE*) cSrc;
    494
    495    size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
    496    if (HUF_isError(hSize)) return hSize;
    497    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
    498    ip += hSize; cSrcSize -= hSize;
    499
    500    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
    501}
    502
    503size_t HUF_decompress4X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
    504                                   const void* cSrc, size_t cSrcSize,
    505                                   void* workSpace, size_t wkspSize)
    506{
    507    return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, 0);
    508}
    509
    510
    511#endif /* HUF_FORCE_DECOMPRESS_X2 */
    512
    513
    514#ifndef HUF_FORCE_DECOMPRESS_X1
    515
    516/* *************************/
    517/* double-symbols decoding */
    518/* *************************/
    519
    520typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX2;  /* double-symbols decoding */
    521typedef struct { BYTE symbol; BYTE weight; } sortedSymbol_t;
    522typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
    523typedef rankValCol_t rankVal_t[HUF_TABLELOG_MAX];
    524
    525
    526/* HUF_fillDTableX2Level2() :
    527 * `rankValOrigin` must be a table of at least (HUF_TABLELOG_MAX + 1) U32 */
    528static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 sizeLog, const U32 consumed,
    529                           const U32* rankValOrigin, const int minWeight,
    530                           const sortedSymbol_t* sortedSymbols, const U32 sortedListSize,
    531                           U32 nbBitsBaseline, U16 baseSeq, U32* wksp, size_t wkspSize)
    532{
    533    HUF_DEltX2 DElt;
    534    U32* rankVal = wksp;
    535
    536    assert(wkspSize >= HUF_TABLELOG_MAX + 1);
    537    (void)wkspSize;
    538    /* get pre-calculated rankVal */
    539    ZSTD_memcpy(rankVal, rankValOrigin, sizeof(U32) * (HUF_TABLELOG_MAX + 1));
    540
    541    /* fill skipped values */
    542    if (minWeight>1) {
    543        U32 i, skipSize = rankVal[minWeight];
    544        MEM_writeLE16(&(DElt.sequence), baseSeq);
    545        DElt.nbBits   = (BYTE)(consumed);
    546        DElt.length   = 1;
    547        for (i = 0; i < skipSize; i++)
    548            DTable[i] = DElt;
    549    }
    550
    551    /* fill DTable */
    552    {   U32 s; for (s=0; s<sortedListSize; s++) {   /* note : sortedSymbols already skipped */
    553            const U32 symbol = sortedSymbols[s].symbol;
    554            const U32 weight = sortedSymbols[s].weight;
    555            const U32 nbBits = nbBitsBaseline - weight;
    556            const U32 length = 1 << (sizeLog-nbBits);
    557            const U32 start = rankVal[weight];
    558            U32 i = start;
    559            const U32 end = start + length;
    560
    561            MEM_writeLE16(&(DElt.sequence), (U16)(baseSeq + (symbol << 8)));
    562            DElt.nbBits = (BYTE)(nbBits + consumed);
    563            DElt.length = 2;
    564            do { DTable[i++] = DElt; } while (i<end);   /* since length >= 1 */
    565
    566            rankVal[weight] += length;
    567    }   }
    568}
    569
    570
    571static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
    572                           const sortedSymbol_t* sortedList, const U32 sortedListSize,
    573                           const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
    574                           const U32 nbBitsBaseline, U32* wksp, size_t wkspSize)
    575{
    576    U32* rankVal = wksp;
    577    const int scaleLog = nbBitsBaseline - targetLog;   /* note : targetLog >= srcLog, hence scaleLog <= 1 */
    578    const U32 minBits  = nbBitsBaseline - maxWeight;
    579    U32 s;
    580
    581    assert(wkspSize >= HUF_TABLELOG_MAX + 1);
    582    wksp += HUF_TABLELOG_MAX + 1;
    583    wkspSize -= HUF_TABLELOG_MAX + 1;
    584
    585    ZSTD_memcpy(rankVal, rankValOrigin, sizeof(U32) * (HUF_TABLELOG_MAX + 1));
    586
    587    /* fill DTable */
    588    for (s=0; s<sortedListSize; s++) {
    589        const U16 symbol = sortedList[s].symbol;
    590        const U32 weight = sortedList[s].weight;
    591        const U32 nbBits = nbBitsBaseline - weight;
    592        const U32 start = rankVal[weight];
    593        const U32 length = 1 << (targetLog-nbBits);
    594
    595        if (targetLog-nbBits >= minBits) {   /* enough room for a second symbol */
    596            U32 sortedRank;
    597            int minWeight = nbBits + scaleLog;
    598            if (minWeight < 1) minWeight = 1;
    599            sortedRank = rankStart[minWeight];
    600            HUF_fillDTableX2Level2(DTable+start, targetLog-nbBits, nbBits,
    601                           rankValOrigin[nbBits], minWeight,
    602                           sortedList+sortedRank, sortedListSize-sortedRank,
    603                           nbBitsBaseline, symbol, wksp, wkspSize);
    604        } else {
    605            HUF_DEltX2 DElt;
    606            MEM_writeLE16(&(DElt.sequence), symbol);
    607            DElt.nbBits = (BYTE)(nbBits);
    608            DElt.length = 1;
    609            {   U32 const end = start + length;
    610                U32 u;
    611                for (u = start; u < end; u++) DTable[u] = DElt;
    612        }   }
    613        rankVal[weight] += length;
    614    }
    615}
    616
    617typedef struct {
    618    rankValCol_t rankVal[HUF_TABLELOG_MAX];
    619    U32 rankStats[HUF_TABLELOG_MAX + 1];
    620    U32 rankStart0[HUF_TABLELOG_MAX + 2];
    621    sortedSymbol_t sortedSymbol[HUF_SYMBOLVALUE_MAX + 1];
    622    BYTE weightList[HUF_SYMBOLVALUE_MAX + 1];
    623    U32 calleeWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
    624} HUF_ReadDTableX2_Workspace;
    625
    626size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
    627                       const void* src, size_t srcSize,
    628                             void* workSpace, size_t wkspSize)
    629{
    630    U32 tableLog, maxW, sizeOfSort, nbSymbols;
    631    DTableDesc dtd = HUF_getDTableDesc(DTable);
    632    U32 const maxTableLog = dtd.maxTableLog;
    633    size_t iSize;
    634    void* dtPtr = DTable+1;   /* force compiler to avoid strict-aliasing */
    635    HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
    636    U32 *rankStart;
    637
    638    HUF_ReadDTableX2_Workspace* const wksp = (HUF_ReadDTableX2_Workspace*)workSpace;
    639
    640    if (sizeof(*wksp) > wkspSize) return ERROR(GENERIC);
    641
    642    rankStart = wksp->rankStart0 + 1;
    643    ZSTD_memset(wksp->rankStats, 0, sizeof(wksp->rankStats));
    644    ZSTD_memset(wksp->rankStart0, 0, sizeof(wksp->rankStart0));
    645
    646    DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(HUF_DTable));   /* if compiler fails here, assertion is wrong */
    647    if (maxTableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
    648    /* ZSTD_memset(weightList, 0, sizeof(weightList)); */  /* is not necessary, even though some analyzer complain ... */
    649
    650    iSize = HUF_readStats_wksp(wksp->weightList, HUF_SYMBOLVALUE_MAX + 1, wksp->rankStats, &nbSymbols, &tableLog, src, srcSize, wksp->calleeWksp, sizeof(wksp->calleeWksp), /* bmi2 */ 0);
    651    if (HUF_isError(iSize)) return iSize;
    652
    653    /* check result */
    654    if (tableLog > maxTableLog) return ERROR(tableLog_tooLarge);   /* DTable can't fit code depth */
    655
    656    /* find maxWeight */
    657    for (maxW = tableLog; wksp->rankStats[maxW]==0; maxW--) {}  /* necessarily finds a solution before 0 */
    658
    659    /* Get start index of each weight */
    660    {   U32 w, nextRankStart = 0;
    661        for (w=1; w<maxW+1; w++) {
    662            U32 curr = nextRankStart;
    663            nextRankStart += wksp->rankStats[w];
    664            rankStart[w] = curr;
    665        }
    666        rankStart[0] = nextRankStart;   /* put all 0w symbols at the end of sorted list*/
    667        sizeOfSort = nextRankStart;
    668    }
    669
    670    /* sort symbols by weight */
    671    {   U32 s;
    672        for (s=0; s<nbSymbols; s++) {
    673            U32 const w = wksp->weightList[s];
    674            U32 const r = rankStart[w]++;
    675            wksp->sortedSymbol[r].symbol = (BYTE)s;
    676            wksp->sortedSymbol[r].weight = (BYTE)w;
    677        }
    678        rankStart[0] = 0;   /* forget 0w symbols; this is beginning of weight(1) */
    679    }
    680
    681    /* Build rankVal */
    682    {   U32* const rankVal0 = wksp->rankVal[0];
    683        {   int const rescale = (maxTableLog-tableLog) - 1;   /* tableLog <= maxTableLog */
    684            U32 nextRankVal = 0;
    685            U32 w;
    686            for (w=1; w<maxW+1; w++) {
    687                U32 curr = nextRankVal;
    688                nextRankVal += wksp->rankStats[w] << (w+rescale);
    689                rankVal0[w] = curr;
    690        }   }
    691        {   U32 const minBits = tableLog+1 - maxW;
    692            U32 consumed;
    693            for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
    694                U32* const rankValPtr = wksp->rankVal[consumed];
    695                U32 w;
    696                for (w = 1; w < maxW+1; w++) {
    697                    rankValPtr[w] = rankVal0[w] >> consumed;
    698    }   }   }   }
    699
    700    HUF_fillDTableX2(dt, maxTableLog,
    701                   wksp->sortedSymbol, sizeOfSort,
    702                   wksp->rankStart0, wksp->rankVal, maxW,
    703                   tableLog+1,
    704                   wksp->calleeWksp, sizeof(wksp->calleeWksp) / sizeof(U32));
    705
    706    dtd.tableLog = (BYTE)maxTableLog;
    707    dtd.tableType = 1;
    708    ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
    709    return iSize;
    710}
    711
    712
    713FORCE_INLINE_TEMPLATE U32
    714HUF_decodeSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
    715{
    716    size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
    717    ZSTD_memcpy(op, dt+val, 2);
    718    BIT_skipBits(DStream, dt[val].nbBits);
    719    return dt[val].length;
    720}
    721
    722FORCE_INLINE_TEMPLATE U32
    723HUF_decodeLastSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
    724{
    725    size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
    726    ZSTD_memcpy(op, dt+val, 1);
    727    if (dt[val].length==1) BIT_skipBits(DStream, dt[val].nbBits);
    728    else {
    729        if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8)) {
    730            BIT_skipBits(DStream, dt[val].nbBits);
    731            if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
    732                /* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
    733                DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);
    734    }   }
    735    return 1;
    736}
    737
    738#define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
    739    ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
    740
    741#define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
    742    if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
    743        ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
    744
    745#define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
    746    if (MEM_64bits()) \
    747        ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
    748
    749HINT_INLINE size_t
    750HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd,
    751                const HUF_DEltX2* const dt, const U32 dtLog)
    752{
    753    BYTE* const pStart = p;
    754
    755    /* up to 8 symbols at a time */
    756    while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-(sizeof(bitDPtr->bitContainer)-1))) {
    757        HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
    758        HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
    759        HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
    760        HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
    761    }
    762
    763    /* closer to end : up to 2 symbols at a time */
    764    while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd-2))
    765        HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
    766
    767    while (p <= pEnd-2)
    768        HUF_DECODE_SYMBOLX2_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
    769
    770    if (p < pEnd)
    771        p += HUF_decodeLastSymbolX2(p, bitDPtr, dt, dtLog);
    772
    773    return p-pStart;
    774}
    775
    776FORCE_INLINE_TEMPLATE size_t
    777HUF_decompress1X2_usingDTable_internal_body(
    778          void* dst,  size_t dstSize,
    779    const void* cSrc, size_t cSrcSize,
    780    const HUF_DTable* DTable)
    781{
    782    BIT_DStream_t bitD;
    783
    784    /* Init */
    785    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
    786
    787    /* decode */
    788    {   BYTE* const ostart = (BYTE*) dst;
    789        BYTE* const oend = ostart + dstSize;
    790        const void* const dtPtr = DTable+1;   /* force compiler to not use strict-aliasing */
    791        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
    792        DTableDesc const dtd = HUF_getDTableDesc(DTable);
    793        HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
    794    }
    795
    796    /* check */
    797    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
    798
    799    /* decoded size */
    800    return dstSize;
    801}
    802
    803FORCE_INLINE_TEMPLATE size_t
    804HUF_decompress4X2_usingDTable_internal_body(
    805          void* dst,  size_t dstSize,
    806    const void* cSrc, size_t cSrcSize,
    807    const HUF_DTable* DTable)
    808{
    809    if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
    810
    811    {   const BYTE* const istart = (const BYTE*) cSrc;
    812        BYTE* const ostart = (BYTE*) dst;
    813        BYTE* const oend = ostart + dstSize;
    814        BYTE* const olimit = oend - (sizeof(size_t)-1);
    815        const void* const dtPtr = DTable+1;
    816        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
    817
    818        /* Init */
    819        BIT_DStream_t bitD1;
    820        BIT_DStream_t bitD2;
    821        BIT_DStream_t bitD3;
    822        BIT_DStream_t bitD4;
    823        size_t const length1 = MEM_readLE16(istart);
    824        size_t const length2 = MEM_readLE16(istart+2);
    825        size_t const length3 = MEM_readLE16(istart+4);
    826        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
    827        const BYTE* const istart1 = istart + 6;  /* jumpTable */
    828        const BYTE* const istart2 = istart1 + length1;
    829        const BYTE* const istart3 = istart2 + length2;
    830        const BYTE* const istart4 = istart3 + length3;
    831        size_t const segmentSize = (dstSize+3) / 4;
    832        BYTE* const opStart2 = ostart + segmentSize;
    833        BYTE* const opStart3 = opStart2 + segmentSize;
    834        BYTE* const opStart4 = opStart3 + segmentSize;
    835        BYTE* op1 = ostart;
    836        BYTE* op2 = opStart2;
    837        BYTE* op3 = opStart3;
    838        BYTE* op4 = opStart4;
    839        U32 endSignal = 1;
    840        DTableDesc const dtd = HUF_getDTableDesc(DTable);
    841        U32 const dtLog = dtd.tableLog;
    842
    843        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
    844        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
    845        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
    846        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
    847        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
    848
    849        /* 16-32 symbols per loop (4-8 symbols per stream) */
    850        for ( ; (endSignal) & (op4 < olimit); ) {
    851#if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
    852            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
    853            HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
    854            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
    855            HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
    856            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
    857            HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
    858            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
    859            HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
    860            endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
    861            endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
    862            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
    863            HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
    864            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
    865            HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
    866            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
    867            HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
    868            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
    869            HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
    870            endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
    871            endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
    872#else
    873            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
    874            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
    875            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
    876            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
    877            HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
    878            HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
    879            HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
    880            HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
    881            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
    882            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
    883            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
    884            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
    885            HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
    886            HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
    887            HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
    888            HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
    889            endSignal = (U32)LIKELY((U32)
    890                        (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
    891                      & (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
    892                      & (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)
    893                      & (BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished));
    894#endif
    895        }
    896
    897        /* check corruption */
    898        if (op1 > opStart2) return ERROR(corruption_detected);
    899        if (op2 > opStart3) return ERROR(corruption_detected);
    900        if (op3 > opStart4) return ERROR(corruption_detected);
    901        /* note : op4 already verified within main loop */
    902
    903        /* finish bitStreams one by one */
    904        HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
    905        HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
    906        HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
    907        HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);
    908
    909        /* check */
    910        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
    911          if (!endCheck) return ERROR(corruption_detected); }
    912
    913        /* decoded size */
    914        return dstSize;
    915    }
    916}
    917
    918HUF_DGEN(HUF_decompress1X2_usingDTable_internal)
    919HUF_DGEN(HUF_decompress4X2_usingDTable_internal)
    920
    921size_t HUF_decompress1X2_usingDTable(
    922          void* dst,  size_t dstSize,
    923    const void* cSrc, size_t cSrcSize,
    924    const HUF_DTable* DTable)
    925{
    926    DTableDesc dtd = HUF_getDTableDesc(DTable);
    927    if (dtd.tableType != 1) return ERROR(GENERIC);
    928    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
    929}
    930
    931size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
    932                                   const void* cSrc, size_t cSrcSize,
    933                                   void* workSpace, size_t wkspSize)
    934{
    935    const BYTE* ip = (const BYTE*) cSrc;
    936
    937    size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize,
    938                                               workSpace, wkspSize);
    939    if (HUF_isError(hSize)) return hSize;
    940    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
    941    ip += hSize; cSrcSize -= hSize;
    942
    943    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
    944}
    945
    946
    947size_t HUF_decompress4X2_usingDTable(
    948          void* dst,  size_t dstSize,
    949    const void* cSrc, size_t cSrcSize,
    950    const HUF_DTable* DTable)
    951{
    952    DTableDesc dtd = HUF_getDTableDesc(DTable);
    953    if (dtd.tableType != 1) return ERROR(GENERIC);
    954    return HUF_decompress4X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
    955}
    956
    957static size_t HUF_decompress4X2_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
    958                                   const void* cSrc, size_t cSrcSize,
    959                                   void* workSpace, size_t wkspSize, int bmi2)
    960{
    961    const BYTE* ip = (const BYTE*) cSrc;
    962
    963    size_t hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize,
    964                                         workSpace, wkspSize);
    965    if (HUF_isError(hSize)) return hSize;
    966    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
    967    ip += hSize; cSrcSize -= hSize;
    968
    969    return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
    970}
    971
    972size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
    973                                   const void* cSrc, size_t cSrcSize,
    974                                   void* workSpace, size_t wkspSize)
    975{
    976    return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, /* bmi2 */ 0);
    977}
    978
    979
    980#endif /* HUF_FORCE_DECOMPRESS_X1 */
    981
    982
    983/* ***********************************/
    984/* Universal decompression selectors */
    985/* ***********************************/
    986
    987size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize,
    988                                    const void* cSrc, size_t cSrcSize,
    989                                    const HUF_DTable* DTable)
    990{
    991    DTableDesc const dtd = HUF_getDTableDesc(DTable);
    992#if defined(HUF_FORCE_DECOMPRESS_X1)
    993    (void)dtd;
    994    assert(dtd.tableType == 0);
    995    return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
    996#elif defined(HUF_FORCE_DECOMPRESS_X2)
    997    (void)dtd;
    998    assert(dtd.tableType == 1);
    999    return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
   1000#else
   1001    return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
   1002                           HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
   1003#endif
   1004}
   1005
   1006size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize,
   1007                                    const void* cSrc, size_t cSrcSize,
   1008                                    const HUF_DTable* DTable)
   1009{
   1010    DTableDesc const dtd = HUF_getDTableDesc(DTable);
   1011#if defined(HUF_FORCE_DECOMPRESS_X1)
   1012    (void)dtd;
   1013    assert(dtd.tableType == 0);
   1014    return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
   1015#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1016    (void)dtd;
   1017    assert(dtd.tableType == 1);
   1018    return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
   1019#else
   1020    return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
   1021                           HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
   1022#endif
   1023}
   1024
   1025
   1026#if !defined(HUF_FORCE_DECOMPRESS_X1) && !defined(HUF_FORCE_DECOMPRESS_X2)
   1027typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
   1028static const algo_time_t algoTime[16 /* Quantization */][3 /* single, double, quad */] =
   1029{
   1030    /* single, double, quad */
   1031    {{0,0}, {1,1}, {2,2}},  /* Q==0 : impossible */
   1032    {{0,0}, {1,1}, {2,2}},  /* Q==1 : impossible */
   1033    {{  38,130}, {1313, 74}, {2151, 38}},   /* Q == 2 : 12-18% */
   1034    {{ 448,128}, {1353, 74}, {2238, 41}},   /* Q == 3 : 18-25% */
   1035    {{ 556,128}, {1353, 74}, {2238, 47}},   /* Q == 4 : 25-32% */
   1036    {{ 714,128}, {1418, 74}, {2436, 53}},   /* Q == 5 : 32-38% */
   1037    {{ 883,128}, {1437, 74}, {2464, 61}},   /* Q == 6 : 38-44% */
   1038    {{ 897,128}, {1515, 75}, {2622, 68}},   /* Q == 7 : 44-50% */
   1039    {{ 926,128}, {1613, 75}, {2730, 75}},   /* Q == 8 : 50-56% */
   1040    {{ 947,128}, {1729, 77}, {3359, 77}},   /* Q == 9 : 56-62% */
   1041    {{1107,128}, {2083, 81}, {4006, 84}},   /* Q ==10 : 62-69% */
   1042    {{1177,128}, {2379, 87}, {4785, 88}},   /* Q ==11 : 69-75% */
   1043    {{1242,128}, {2415, 93}, {5155, 84}},   /* Q ==12 : 75-81% */
   1044    {{1349,128}, {2644,106}, {5260,106}},   /* Q ==13 : 81-87% */
   1045    {{1455,128}, {2422,124}, {4174,124}},   /* Q ==14 : 87-93% */
   1046    {{ 722,128}, {1891,145}, {1936,146}},   /* Q ==15 : 93-99% */
   1047};
   1048#endif
   1049
   1050/* HUF_selectDecoder() :
   1051 *  Tells which decoder is likely to decode faster,
   1052 *  based on a set of pre-computed metrics.
   1053 * @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
   1054 *  Assumption : 0 < dstSize <= 128 KB */
   1055U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize)
   1056{
   1057    assert(dstSize > 0);
   1058    assert(dstSize <= 128*1024);
   1059#if defined(HUF_FORCE_DECOMPRESS_X1)
   1060    (void)dstSize;
   1061    (void)cSrcSize;
   1062    return 0;
   1063#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1064    (void)dstSize;
   1065    (void)cSrcSize;
   1066    return 1;
   1067#else
   1068    /* decoder timing evaluation */
   1069    {   U32 const Q = (cSrcSize >= dstSize) ? 15 : (U32)(cSrcSize * 16 / dstSize);   /* Q < 16 */
   1070        U32 const D256 = (U32)(dstSize >> 8);
   1071        U32 const DTime0 = algoTime[Q][0].tableTime + (algoTime[Q][0].decode256Time * D256);
   1072        U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * D256);
   1073        DTime1 += DTime1 >> 3;  /* advantage to algorithm using less memory, to reduce cache eviction */
   1074        return DTime1 < DTime0;
   1075    }
   1076#endif
   1077}
   1078
   1079
   1080size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst,
   1081                                     size_t dstSize, const void* cSrc,
   1082                                     size_t cSrcSize, void* workSpace,
   1083                                     size_t wkspSize)
   1084{
   1085    /* validation checks */
   1086    if (dstSize == 0) return ERROR(dstSize_tooSmall);
   1087    if (cSrcSize == 0) return ERROR(corruption_detected);
   1088
   1089    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
   1090#if defined(HUF_FORCE_DECOMPRESS_X1)
   1091        (void)algoNb;
   1092        assert(algoNb == 0);
   1093        return HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
   1094#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1095        (void)algoNb;
   1096        assert(algoNb == 1);
   1097        return HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
   1098#else
   1099        return algoNb ? HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
   1100                            cSrcSize, workSpace, wkspSize):
   1101                        HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
   1102#endif
   1103    }
   1104}
   1105
   1106size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
   1107                                  const void* cSrc, size_t cSrcSize,
   1108                                  void* workSpace, size_t wkspSize)
   1109{
   1110    /* validation checks */
   1111    if (dstSize == 0) return ERROR(dstSize_tooSmall);
   1112    if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
   1113    if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
   1114    if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
   1115
   1116    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
   1117#if defined(HUF_FORCE_DECOMPRESS_X1)
   1118        (void)algoNb;
   1119        assert(algoNb == 0);
   1120        return HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
   1121                                cSrcSize, workSpace, wkspSize);
   1122#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1123        (void)algoNb;
   1124        assert(algoNb == 1);
   1125        return HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
   1126                                cSrcSize, workSpace, wkspSize);
   1127#else
   1128        return algoNb ? HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
   1129                                cSrcSize, workSpace, wkspSize):
   1130                        HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
   1131                                cSrcSize, workSpace, wkspSize);
   1132#endif
   1133    }
   1134}
   1135
   1136
   1137size_t HUF_decompress1X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
   1138{
   1139    DTableDesc const dtd = HUF_getDTableDesc(DTable);
   1140#if defined(HUF_FORCE_DECOMPRESS_X1)
   1141    (void)dtd;
   1142    assert(dtd.tableType == 0);
   1143    return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
   1144#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1145    (void)dtd;
   1146    assert(dtd.tableType == 1);
   1147    return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
   1148#else
   1149    return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
   1150                           HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
   1151#endif
   1152}
   1153
   1154#ifndef HUF_FORCE_DECOMPRESS_X2
   1155size_t HUF_decompress1X1_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int bmi2)
   1156{
   1157    const BYTE* ip = (const BYTE*) cSrc;
   1158
   1159    size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
   1160    if (HUF_isError(hSize)) return hSize;
   1161    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
   1162    ip += hSize; cSrcSize -= hSize;
   1163
   1164    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
   1165}
   1166#endif
   1167
   1168size_t HUF_decompress4X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
   1169{
   1170    DTableDesc const dtd = HUF_getDTableDesc(DTable);
   1171#if defined(HUF_FORCE_DECOMPRESS_X1)
   1172    (void)dtd;
   1173    assert(dtd.tableType == 0);
   1174    return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
   1175#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1176    (void)dtd;
   1177    assert(dtd.tableType == 1);
   1178    return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
   1179#else
   1180    return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
   1181                           HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
   1182#endif
   1183}
   1184
   1185size_t HUF_decompress4X_hufOnly_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int bmi2)
   1186{
   1187    /* validation checks */
   1188    if (dstSize == 0) return ERROR(dstSize_tooSmall);
   1189    if (cSrcSize == 0) return ERROR(corruption_detected);
   1190
   1191    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
   1192#if defined(HUF_FORCE_DECOMPRESS_X1)
   1193        (void)algoNb;
   1194        assert(algoNb == 0);
   1195        return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
   1196#elif defined(HUF_FORCE_DECOMPRESS_X2)
   1197        (void)algoNb;
   1198        assert(algoNb == 1);
   1199        return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
   1200#else
   1201        return algoNb ? HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2) :
   1202                        HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
   1203#endif
   1204    }
   1205}
   1206