Compress-Stream-Zstd

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ext/zstd/lib/decompress/huf_decompress.c  view on Meta::CPAN

        BYTE* op1 = ostart;
        BYTE* op2 = opStart2;
        BYTE* op3 = opStart3;
        BYTE* op4 = opStart4;
        DTableDesc const dtd = HUF_getDTableDesc(DTable);
        U32 const dtLog = dtd.tableLog;
        U32 endSignal = 1;

        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
        if (opStart4 > oend) return ERROR(corruption_detected);      /* overflow */
        if (dstSize < 6) return ERROR(corruption_detected);         /* stream 4-split doesn't work */
        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );

        /* up to 16 symbols per loop (4 symbols per stream) in 64-bit mode */
        if ((size_t)(oend - op4) >= sizeof(size_t)) {
            for ( ; (endSignal) & (op4 < olimit) ; ) {
                HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
                HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
                HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
                HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
                HUF_DECODE_SYMBOLX1_1(op1, &bitD1);
                HUF_DECODE_SYMBOLX1_1(op2, &bitD2);
                HUF_DECODE_SYMBOLX1_1(op3, &bitD3);
                HUF_DECODE_SYMBOLX1_1(op4, &bitD4);
                HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
                HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
                HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
                HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
                HUF_DECODE_SYMBOLX1_0(op1, &bitD1);
                HUF_DECODE_SYMBOLX1_0(op2, &bitD2);
                HUF_DECODE_SYMBOLX1_0(op3, &bitD3);
                HUF_DECODE_SYMBOLX1_0(op4, &bitD4);
                endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
                endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
                endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
                endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
            }
        }

        /* check corruption */
        /* note : should not be necessary : op# advance in lock step, and we control op4.
         *        but curiously, binary generated by gcc 7.2 & 7.3 with -mbmi2 runs faster when >=1 test is present */
        if (op1 > opStart2) return ERROR(corruption_detected);
        if (op2 > opStart3) return ERROR(corruption_detected);
        if (op3 > opStart4) return ERROR(corruption_detected);
        /* note : op4 supposed already verified within main loop */

        /* finish bitStreams one by one */
        HUF_decodeStreamX1(op1, &bitD1, opStart2, dt, dtLog);
        HUF_decodeStreamX1(op2, &bitD2, opStart3, dt, dtLog);
        HUF_decodeStreamX1(op3, &bitD3, opStart4, dt, dtLog);
        HUF_decodeStreamX1(op4, &bitD4, oend,     dt, dtLog);

        /* check */
        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
          if (!endCheck) return ERROR(corruption_detected); }

        /* decoded size */
        return dstSize;
    }
}

#if HUF_NEED_BMI2_FUNCTION
static BMI2_TARGET_ATTRIBUTE
size_t HUF_decompress4X1_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
                    size_t cSrcSize, HUF_DTable const* DTable) {
    return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
#endif

static
size_t HUF_decompress4X1_usingDTable_internal_default(void* dst, size_t dstSize, void const* cSrc,
                    size_t cSrcSize, HUF_DTable const* DTable) {
    return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}

#if ZSTD_ENABLE_ASM_X86_64_BMI2

HUF_ASM_DECL void HUF_decompress4X1_usingDTable_internal_fast_asm_loop(HUF_DecompressFastArgs* args) ZSTDLIB_HIDDEN;

#endif

static HUF_FAST_BMI2_ATTRS
void HUF_decompress4X1_usingDTable_internal_fast_c_loop(HUF_DecompressFastArgs* args)
{
    U64 bits[4];
    BYTE const* ip[4];
    BYTE* op[4];
    U16 const* const dtable = (U16 const*)args->dt;
    BYTE* const oend = args->oend;
    BYTE const* const ilimit = args->ilimit;

    /* Copy the arguments to local variables */
    ZSTD_memcpy(&bits, &args->bits, sizeof(bits));
    ZSTD_memcpy((void*)(&ip), &args->ip, sizeof(ip));
    ZSTD_memcpy(&op, &args->op, sizeof(op));

    assert(MEM_isLittleEndian());
    assert(!MEM_32bits());

    for (;;) {
        BYTE* olimit;
        int stream;
        int symbol;

        /* Assert loop preconditions */
#ifndef NDEBUG
        for (stream = 0; stream < 4; ++stream) {
            assert(op[stream] <= (stream == 3 ? oend : op[stream + 1]));
            assert(ip[stream] >= ilimit);
        }
#endif
        /* Compute olimit */
        {
            /* Each iteration produces 5 output symbols per stream */
            size_t const oiters = (size_t)(oend - op[3]) / 5;
            /* Each iteration consumes up to 11 bits * 5 = 55 bits < 7 bytes
             * per stream.

ext/zstd/lib/decompress/huf_decompress.c  view on Meta::CPAN


    /* Save the final values of each of the state variables back to args. */
    ZSTD_memcpy(&args->bits, &bits, sizeof(bits));
    ZSTD_memcpy((void*)(&args->ip), &ip, sizeof(ip));
    ZSTD_memcpy(&args->op, &op, sizeof(op));
}

/**
 * @returns @p dstSize on success (>= 6)
 *          0 if the fallback implementation should be used
 *          An error if an error occurred
 */
static HUF_FAST_BMI2_ATTRS
size_t
HUF_decompress4X1_usingDTable_internal_fast(
          void* dst,  size_t dstSize,
    const void* cSrc, size_t cSrcSize,
    const HUF_DTable* DTable,
    HUF_DecompressFastLoopFn loopFn)
{
    void const* dt = DTable + 1;
    const BYTE* const iend = (const BYTE*)cSrc + 6;
    BYTE* const oend = (BYTE*)dst + dstSize;
    HUF_DecompressFastArgs args;
    {   size_t const ret = HUF_DecompressFastArgs_init(&args, dst, dstSize, cSrc, cSrcSize, DTable);
        FORWARD_IF_ERROR(ret, "Failed to init fast loop args");
        if (ret == 0)
            return 0;
    }

    assert(args.ip[0] >= args.ilimit);
    loopFn(&args);

    /* Our loop guarantees that ip[] >= ilimit and that we haven't
    * overwritten any op[].
    */
    assert(args.ip[0] >= iend);
    assert(args.ip[1] >= iend);
    assert(args.ip[2] >= iend);
    assert(args.ip[3] >= iend);
    assert(args.op[3] <= oend);
    (void)iend;

    /* finish bit streams one by one. */
    {   size_t const segmentSize = (dstSize+3) / 4;
        BYTE* segmentEnd = (BYTE*)dst;
        int i;
        for (i = 0; i < 4; ++i) {
            BIT_DStream_t bit;
            if (segmentSize <= (size_t)(oend - segmentEnd))
                segmentEnd += segmentSize;
            else
                segmentEnd = oend;
            FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
            /* Decompress and validate that we've produced exactly the expected length. */
            args.op[i] += HUF_decodeStreamX1(args.op[i], &bit, segmentEnd, (HUF_DEltX1 const*)dt, HUF_DECODER_FAST_TABLELOG);
            if (args.op[i] != segmentEnd) return ERROR(corruption_detected);
        }
    }

    /* decoded size */
    assert(dstSize != 0);
    return dstSize;
}

HUF_DGEN(HUF_decompress1X1_usingDTable_internal)

static size_t HUF_decompress4X1_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
                    size_t cSrcSize, HUF_DTable const* DTable, int flags)
{
    HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X1_usingDTable_internal_default;
    HUF_DecompressFastLoopFn loopFn = HUF_decompress4X1_usingDTable_internal_fast_c_loop;

#if DYNAMIC_BMI2
    if (flags & HUF_flags_bmi2) {
        fallbackFn = HUF_decompress4X1_usingDTable_internal_bmi2;
# if ZSTD_ENABLE_ASM_X86_64_BMI2
        if (!(flags & HUF_flags_disableAsm)) {
            loopFn = HUF_decompress4X1_usingDTable_internal_fast_asm_loop;
        }
# endif
    } else {
        return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
    }
#endif

#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
    if (!(flags & HUF_flags_disableAsm)) {
        loopFn = HUF_decompress4X1_usingDTable_internal_fast_asm_loop;
    }
#endif

    if (!(flags & HUF_flags_disableFast)) {
        size_t const ret = HUF_decompress4X1_usingDTable_internal_fast(dst, dstSize, cSrc, cSrcSize, DTable, loopFn);
        if (ret != 0)
            return ret;
    }
    return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}

static size_t HUF_decompress4X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
                                   const void* cSrc, size_t cSrcSize,
                                   void* workSpace, size_t wkspSize, int flags)
{
    const BYTE* ip = (const BYTE*) cSrc;

    size_t const hSize = HUF_readDTableX1_wksp(dctx, cSrc, cSrcSize, workSpace, wkspSize, flags);
    if (HUF_isError(hSize)) return hSize;
    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
    ip += hSize; cSrcSize -= hSize;

    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, flags);
}

#endif /* HUF_FORCE_DECOMPRESS_X2 */


#ifndef HUF_FORCE_DECOMPRESS_X1

/* *************************/
/* double-symbols decoding */

ext/zstd/lib/decompress/huf_decompress.c  view on Meta::CPAN

        if (dtLog <= 11 && MEM_64bits()) {
            /* up to 10 symbols at a time */
            while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-9)) {
                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
            }
        } else {
            /* up to 8 symbols at a time */
            while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-(sizeof(bitDPtr->bitContainer)-1))) {
                HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
            }
        }
    } else {
        BIT_reloadDStream(bitDPtr);
    }

    /* closer to end : up to 2 symbols at a time */
    if ((size_t)(pEnd - p) >= 2) {
        while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd-2))
            HUF_DECODE_SYMBOLX2_0(p, bitDPtr);

        while (p <= pEnd-2)
            HUF_DECODE_SYMBOLX2_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
    }

    if (p < pEnd)
        p += HUF_decodeLastSymbolX2(p, bitDPtr, dt, dtLog);

    return p-pStart;
}

FORCE_INLINE_TEMPLATE size_t
HUF_decompress1X2_usingDTable_internal_body(
          void* dst,  size_t dstSize,
    const void* cSrc, size_t cSrcSize,
    const HUF_DTable* DTable)
{
    BIT_DStream_t bitD;

    /* Init */
    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );

    /* decode */
    {   BYTE* const ostart = (BYTE*) dst;
        BYTE* const oend = ostart + dstSize;
        const void* const dtPtr = DTable+1;   /* force compiler to not use strict-aliasing */
        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
        DTableDesc const dtd = HUF_getDTableDesc(DTable);
        HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
    }

    /* check */
    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);

    /* decoded size */
    return dstSize;
}

/* HUF_decompress4X2_usingDTable_internal_body():
 * Conditions:
 * @dstSize >= 6
 */
FORCE_INLINE_TEMPLATE size_t
HUF_decompress4X2_usingDTable_internal_body(
          void* dst,  size_t dstSize,
    const void* cSrc, size_t cSrcSize,
    const HUF_DTable* DTable)
{
    if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */

    {   const BYTE* const istart = (const BYTE*) cSrc;
        BYTE* const ostart = (BYTE*) dst;
        BYTE* const oend = ostart + dstSize;
        BYTE* const olimit = oend - (sizeof(size_t)-1);
        const void* const dtPtr = DTable+1;
        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;

        /* Init */
        BIT_DStream_t bitD1;
        BIT_DStream_t bitD2;
        BIT_DStream_t bitD3;
        BIT_DStream_t bitD4;
        size_t const length1 = MEM_readLE16(istart);
        size_t const length2 = MEM_readLE16(istart+2);
        size_t const length3 = MEM_readLE16(istart+4);
        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
        const BYTE* const istart1 = istart + 6;  /* jumpTable */
        const BYTE* const istart2 = istart1 + length1;
        const BYTE* const istart3 = istart2 + length2;
        const BYTE* const istart4 = istart3 + length3;
        size_t const segmentSize = (dstSize+3) / 4;
        BYTE* const opStart2 = ostart + segmentSize;
        BYTE* const opStart3 = opStart2 + segmentSize;
        BYTE* const opStart4 = opStart3 + segmentSize;
        BYTE* op1 = ostart;
        BYTE* op2 = opStart2;
        BYTE* op3 = opStart3;
        BYTE* op4 = opStart4;
        U32 endSignal = 1;
        DTableDesc const dtd = HUF_getDTableDesc(DTable);
        U32 const dtLog = dtd.tableLog;

        if (length4 > cSrcSize) return ERROR(corruption_detected);  /* overflow */
        if (opStart4 > oend) return ERROR(corruption_detected);     /* overflow */
        if (dstSize < 6) return ERROR(corruption_detected);         /* stream 4-split doesn't work */
        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );

        /* 16-32 symbols per loop (4-8 symbols per stream) */
        if ((size_t)(oend - op4) >= sizeof(size_t)) {
            for ( ; (endSignal) & (op4 < olimit); ) {
#if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);

ext/zstd/lib/decompress/huf_decompress.c  view on Meta::CPAN

                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
                HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
                endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
                endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
                HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
                HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
                endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
                endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
#else
                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
                HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
                HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
                HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
                HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
                HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
                HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
                endSignal = (U32)LIKELY((U32)
                            (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
                        & (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
                        & (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)
                        & (BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished));
#endif
            }
        }

        /* check corruption */
        if (op1 > opStart2) return ERROR(corruption_detected);
        if (op2 > opStart3) return ERROR(corruption_detected);
        if (op3 > opStart4) return ERROR(corruption_detected);
        /* note : op4 already verified within main loop */

        /* finish bitStreams one by one */
        HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
        HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
        HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
        HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);

        /* check */
        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
          if (!endCheck) return ERROR(corruption_detected); }

        /* decoded size */
        return dstSize;
    }
}

#if HUF_NEED_BMI2_FUNCTION
static BMI2_TARGET_ATTRIBUTE
size_t HUF_decompress4X2_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
                    size_t cSrcSize, HUF_DTable const* DTable) {
    return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
#endif

static
size_t HUF_decompress4X2_usingDTable_internal_default(void* dst, size_t dstSize, void const* cSrc,
                    size_t cSrcSize, HUF_DTable const* DTable) {
    return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}

#if ZSTD_ENABLE_ASM_X86_64_BMI2

HUF_ASM_DECL void HUF_decompress4X2_usingDTable_internal_fast_asm_loop(HUF_DecompressFastArgs* args) ZSTDLIB_HIDDEN;

#endif

static HUF_FAST_BMI2_ATTRS
void HUF_decompress4X2_usingDTable_internal_fast_c_loop(HUF_DecompressFastArgs* args)
{
    U64 bits[4];
    BYTE const* ip[4];
    BYTE* op[4];
    BYTE* oend[4];
    HUF_DEltX2 const* const dtable = (HUF_DEltX2 const*)args->dt;
    BYTE const* const ilimit = args->ilimit;

    /* Copy the arguments to local registers. */
    ZSTD_memcpy(&bits, &args->bits, sizeof(bits));
    ZSTD_memcpy((void*)(&ip), &args->ip, sizeof(ip));
    ZSTD_memcpy(&op, &args->op, sizeof(op));

    oend[0] = op[1];
    oend[1] = op[2];
    oend[2] = op[3];
    oend[3] = args->oend;

    assert(MEM_isLittleEndian());
    assert(!MEM_32bits());

    for (;;) {
        BYTE* olimit;
        int stream;
        int symbol;

        /* Assert loop preconditions */
#ifndef NDEBUG
        for (stream = 0; stream < 4; ++stream) {
            assert(op[stream] <= oend[stream]);
            assert(ip[stream] >= ilimit);
        }
#endif
        /* Compute olimit */

ext/zstd/lib/decompress/huf_decompress.c  view on Meta::CPAN

             * iterations yet. This saves us maintaining an iters counter,
             * at the expense of computing the remaining # of iterations
             * more frequently.
             */
            olimit = op[3] + (iters * 5);

            /* Exit the fast decoding loop if we are too close to the end. */
            if (op[3] + 10 > olimit)
                break;

            /* Exit the decoding loop if any input pointer has crossed the
             * previous one. This indicates corruption, and a precondition
             * to our loop is that ip[i] >= ip[0].
             */
            for (stream = 1; stream < 4; ++stream) {
                if (ip[stream] < ip[stream - 1])
                    goto _out;
            }
        }

#ifndef NDEBUG
        for (stream = 1; stream < 4; ++stream) {
            assert(ip[stream] >= ip[stream - 1]);
        }
#endif

        do {
            /* Do 5 table lookups for each of the first 3 streams */
            for (symbol = 0; symbol < 5; ++symbol) {
                for (stream = 0; stream < 3; ++stream) {
                    int const index = (int)(bits[stream] >> 53);
                    HUF_DEltX2 const entry = dtable[index];
                    MEM_write16(op[stream], entry.sequence);
                    bits[stream] <<= (entry.nbBits);
                    op[stream] += (entry.length);
                }
            }
            /* Do 1 table lookup from the final stream */
            {
                int const index = (int)(bits[3] >> 53);
                HUF_DEltX2 const entry = dtable[index];
                MEM_write16(op[3], entry.sequence);
                bits[3] <<= (entry.nbBits);
                op[3] += (entry.length);
            }
            /* Do 4 table lookups from the final stream & reload bitstreams */
            for (stream = 0; stream < 4; ++stream) {
                /* Do a table lookup from the final stream.
                 * This is interleaved with the reloading to reduce register
                 * pressure. This shouldn't be necessary, but compilers can
                 * struggle with codegen with high register pressure.
                 */
                {
                    int const index = (int)(bits[3] >> 53);
                    HUF_DEltX2 const entry = dtable[index];
                    MEM_write16(op[3], entry.sequence);
                    bits[3] <<= (entry.nbBits);
                    op[3] += (entry.length);
                }
                /* Reload the bistreams. The final bitstream must be reloaded
                 * after the 5th symbol was decoded.
                 */
                {
                    int const ctz = ZSTD_countTrailingZeros64(bits[stream]);
                    int const nbBits = ctz & 7;
                    int const nbBytes = ctz >> 3;
                    ip[stream] -= nbBytes;
                    bits[stream] = MEM_read64(ip[stream]) | 1;
                    bits[stream] <<= nbBits;
                }
            }
        } while (op[3] < olimit);
    }

_out:

    /* Save the final values of each of the state variables back to args. */
    ZSTD_memcpy(&args->bits, &bits, sizeof(bits));
    ZSTD_memcpy((void*)(&args->ip), &ip, sizeof(ip));
    ZSTD_memcpy(&args->op, &op, sizeof(op));
}


static HUF_FAST_BMI2_ATTRS size_t
HUF_decompress4X2_usingDTable_internal_fast(
          void* dst,  size_t dstSize,
    const void* cSrc, size_t cSrcSize,
    const HUF_DTable* DTable,
    HUF_DecompressFastLoopFn loopFn) {
    void const* dt = DTable + 1;
    const BYTE* const iend = (const BYTE*)cSrc + 6;
    BYTE* const oend = (BYTE*)dst + dstSize;
    HUF_DecompressFastArgs args;
    {
        size_t const ret = HUF_DecompressFastArgs_init(&args, dst, dstSize, cSrc, cSrcSize, DTable);
        FORWARD_IF_ERROR(ret, "Failed to init asm args");
        if (ret == 0)
            return 0;
    }

    assert(args.ip[0] >= args.ilimit);
    loopFn(&args);

    /* note : op4 already verified within main loop */
    assert(args.ip[0] >= iend);
    assert(args.ip[1] >= iend);
    assert(args.ip[2] >= iend);
    assert(args.ip[3] >= iend);
    assert(args.op[3] <= oend);
    (void)iend;

    /* finish bitStreams one by one */
    {
        size_t const segmentSize = (dstSize+3) / 4;
        BYTE* segmentEnd = (BYTE*)dst;
        int i;
        for (i = 0; i < 4; ++i) {
            BIT_DStream_t bit;
            if (segmentSize <= (size_t)(oend - segmentEnd))
                segmentEnd += segmentSize;
            else
                segmentEnd = oend;
            FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
            args.op[i] += HUF_decodeStreamX2(args.op[i], &bit, segmentEnd, (HUF_DEltX2 const*)dt, HUF_DECODER_FAST_TABLELOG);
            if (args.op[i] != segmentEnd)
                return ERROR(corruption_detected);
        }
    }

    /* decoded size */
    return dstSize;
}

static size_t HUF_decompress4X2_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
                    size_t cSrcSize, HUF_DTable const* DTable, int flags)
{
    HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X2_usingDTable_internal_default;
    HUF_DecompressFastLoopFn loopFn = HUF_decompress4X2_usingDTable_internal_fast_c_loop;

#if DYNAMIC_BMI2
    if (flags & HUF_flags_bmi2) {
        fallbackFn = HUF_decompress4X2_usingDTable_internal_bmi2;
# if ZSTD_ENABLE_ASM_X86_64_BMI2
        if (!(flags & HUF_flags_disableAsm)) {
            loopFn = HUF_decompress4X2_usingDTable_internal_fast_asm_loop;
        }
# endif
    } else {
        return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
    }
#endif

#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
    if (!(flags & HUF_flags_disableAsm)) {
        loopFn = HUF_decompress4X2_usingDTable_internal_fast_asm_loop;
    }
#endif

    if (!(flags & HUF_flags_disableFast)) {
        size_t const ret = HUF_decompress4X2_usingDTable_internal_fast(dst, dstSize, cSrc, cSrcSize, DTable, loopFn);
        if (ret != 0)
            return ret;
    }
    return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}

HUF_DGEN(HUF_decompress1X2_usingDTable_internal)

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)
{
    const BYTE* ip = (const BYTE*) cSrc;

    size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize,
                                               workSpace, wkspSize, flags);
    if (HUF_isError(hSize)) return hSize;
    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
    ip += hSize; cSrcSize -= hSize;

    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, flags);
}

static size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
                                   const void* cSrc, size_t cSrcSize,
                                   void* workSpace, size_t wkspSize, int flags)
{
    const BYTE* ip = (const BYTE*) cSrc;

    size_t hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize,



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