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   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#include "../common/zstd_internal.h"
  26
  27/* **************************************************************
  28*  Constants
  29****************************************************************/
  30
  31#define HUF_DECODER_FAST_TABLELOG 11
  32
  33/* **************************************************************
  34*  Macros
  35****************************************************************/
  36
  37/* These two optional macros force the use one way or another of the two
  38 * Huffman decompression implementations. You can't force in both directions
  39 * at the same time.
  40 */
  41#if defined(HUF_FORCE_DECOMPRESS_X1) && \
  42    defined(HUF_FORCE_DECOMPRESS_X2)
  43#error "Cannot force the use of the X1 and X2 decoders at the same time!"
  44#endif
  45
  46#if ZSTD_ENABLE_ASM_X86_64_BMI2 && DYNAMIC_BMI2
  47# define HUF_ASM_X86_64_BMI2_ATTRS BMI2_TARGET_ATTRIBUTE
  48#else
  49# define HUF_ASM_X86_64_BMI2_ATTRS
  50#endif
  51
  52#define HUF_EXTERN_C
  53#define HUF_ASM_DECL HUF_EXTERN_C
  54
  55#if DYNAMIC_BMI2 || (ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__))
  56# define HUF_NEED_BMI2_FUNCTION 1
  57#else
  58# define HUF_NEED_BMI2_FUNCTION 0
  59#endif
  60
  61#if !(ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__))
  62# define HUF_NEED_DEFAULT_FUNCTION 1
  63#else
  64# define HUF_NEED_DEFAULT_FUNCTION 0
  65#endif
  66
  67/* **************************************************************
  68*  Error Management
  69****************************************************************/
  70#define HUF_isError ERR_isError
  71
  72
  73/* **************************************************************
  74*  Byte alignment for workSpace management
  75****************************************************************/
  76#define HUF_ALIGN(x, a)         HUF_ALIGN_MASK((x), (a) - 1)
  77#define HUF_ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
  78
  79
  80/* **************************************************************
  81*  BMI2 Variant Wrappers
  82****************************************************************/
  83#if DYNAMIC_BMI2
  84
  85#define HUF_DGEN(fn)                                                        \
  86                                                                            \
  87    static size_t fn##_default(                                             \
  88                  void* dst,  size_t dstSize,                               \
  89            const void* cSrc, size_t cSrcSize,                              \
  90            const HUF_DTable* DTable)                                       \
  91    {                                                                       \
  92        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
  93    }                                                                       \
  94                                                                            \
  95    static BMI2_TARGET_ATTRIBUTE size_t fn##_bmi2(                          \
  96                  void* dst,  size_t dstSize,                               \
  97            const void* cSrc, size_t cSrcSize,                              \
  98            const HUF_DTable* DTable)                                       \
  99    {                                                                       \
 100        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
 101    }                                                                       \
 102                                                                            \
 103    static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
 104                     size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
 105    {                                                                       \
 106        if (bmi2) {                                                         \
 107            return fn##_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);         \
 108        }                                                                   \
 109        return fn##_default(dst, dstSize, cSrc, cSrcSize, DTable);          \
 110    }
 111
 112#else
 113
 114#define HUF_DGEN(fn)                                                        \
 115    static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
 116                     size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
 117    {                                                                       \
 118        (void)bmi2;                                                         \
 119        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
 120    }
 121
 122#endif
 123
 124
 125/*-***************************/
 126/*  generic DTableDesc       */
 127/*-***************************/
 128typedef struct { BYTE maxTableLog; BYTE tableType; BYTE tableLog; BYTE reserved; } DTableDesc;
 129
 130static DTableDesc HUF_getDTableDesc(const HUF_DTable* table)
 131{
 132    DTableDesc dtd;
 133    ZSTD_memcpy(&dtd, table, sizeof(dtd));
 134    return dtd;
 135}
 136
 137#if ZSTD_ENABLE_ASM_X86_64_BMI2
 138
 139static size_t HUF_initDStream(BYTE const* ip) {
 140    BYTE const lastByte = ip[7];
 141    size_t const bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;
 142    size_t const value = MEM_readLEST(ip) | 1;
 143    assert(bitsConsumed <= 8);
 144    return value << bitsConsumed;
 145}
 146typedef struct {
 147    BYTE const* ip[4];
 148    BYTE* op[4];
 149    U64 bits[4];
 150    void const* dt;
 151    BYTE const* ilimit;
 152    BYTE* oend;
 153    BYTE const* iend[4];
 154} HUF_DecompressAsmArgs;
 155
 156/*
 157 * Initializes args for the asm decoding loop.
 158 * @returns 0 on success
 159 *          1 if the fallback implementation should be used.
 160 *          Or an error code on failure.
 161 */
 162static size_t HUF_DecompressAsmArgs_init(HUF_DecompressAsmArgs* args, void* dst, size_t dstSize, void const* src, size_t srcSize, const HUF_DTable* DTable)
 163{
 164    void const* dt = DTable + 1;
 165    U32 const dtLog = HUF_getDTableDesc(DTable).tableLog;
 166
 167    const BYTE* const ilimit = (const BYTE*)src + 6 + 8;
 168
 169    BYTE* const oend = (BYTE*)dst + dstSize;
 170
 171    /* The following condition is false on x32 platform,
 172     * but HUF_asm is not compatible with this ABI */
 173    if (!(MEM_isLittleEndian() && !MEM_32bits())) return 1;
 174
 175    /* strict minimum : jump table + 1 byte per stream */
 176    if (srcSize < 10)
 177        return ERROR(corruption_detected);
 178
 179    /* Must have at least 8 bytes per stream because we don't handle initializing smaller bit containers.
 180     * If table log is not correct at this point, fallback to the old decoder.
 181     * On small inputs we don't have enough data to trigger the fast loop, so use the old decoder.
 182     */
 183    if (dtLog != HUF_DECODER_FAST_TABLELOG)
 184        return 1;
 185
 186    /* Read the jump table. */
 187    {
 188        const BYTE* const istart = (const BYTE*)src;
 189        size_t const length1 = MEM_readLE16(istart);
 190        size_t const length2 = MEM_readLE16(istart+2);
 191        size_t const length3 = MEM_readLE16(istart+4);
 192        size_t const length4 = srcSize - (length1 + length2 + length3 + 6);
 193        args->iend[0] = istart + 6;  /* jumpTable */
 194        args->iend[1] = args->iend[0] + length1;
 195        args->iend[2] = args->iend[1] + length2;
 196        args->iend[3] = args->iend[2] + length3;
 197
 198        /* HUF_initDStream() requires this, and this small of an input
 199         * won't benefit from the ASM loop anyways.
 200         * length1 must be >= 16 so that ip[0] >= ilimit before the loop
 201         * starts.
 202         */
 203        if (length1 < 16 || length2 < 8 || length3 < 8 || length4 < 8)
 204            return 1;
 205        if (length4 > srcSize) return ERROR(corruption_detected);   /* overflow */
 206    }
 207    /* ip[] contains the position that is currently loaded into bits[]. */
 208    args->ip[0] = args->iend[1] - sizeof(U64);
 209    args->ip[1] = args->iend[2] - sizeof(U64);
 210    args->ip[2] = args->iend[3] - sizeof(U64);
 211    args->ip[3] = (BYTE const*)src + srcSize - sizeof(U64);
 212
 213    /* op[] contains the output pointers. */
 214    args->op[0] = (BYTE*)dst;
 215    args->op[1] = args->op[0] + (dstSize+3)/4;
 216    args->op[2] = args->op[1] + (dstSize+3)/4;
 217    args->op[3] = args->op[2] + (dstSize+3)/4;
 218
 219    /* No point to call the ASM loop for tiny outputs. */
 220    if (args->op[3] >= oend)
 221        return 1;
 222
 223    /* bits[] is the bit container.
 224        * It is read from the MSB down to the LSB.
 225        * It is shifted left as it is read, and zeros are
 226        * shifted in. After the lowest valid bit a 1 is
 227        * set, so that CountTrailingZeros(bits[]) can be used
 228        * to count how many bits we've consumed.
 229        */
 230    args->bits[0] = HUF_initDStream(args->ip[0]);
 231    args->bits[1] = HUF_initDStream(args->ip[1]);
 232    args->bits[2] = HUF_initDStream(args->ip[2]);
 233    args->bits[3] = HUF_initDStream(args->ip[3]);
 234
 235    /* If ip[] >= ilimit, it is guaranteed to be safe to
 236        * reload bits[]. It may be beyond its section, but is
 237        * guaranteed to be valid (>= istart).
 238        */
 239    args->ilimit = ilimit;
 240
 241    args->oend = oend;
 242    args->dt = dt;
 243
 244    return 0;
 245}
 246
 247static size_t HUF_initRemainingDStream(BIT_DStream_t* bit, HUF_DecompressAsmArgs const* args, int stream, BYTE* segmentEnd)
 248{
 249    /* Validate that we haven't overwritten. */
 250    if (args->op[stream] > segmentEnd)
 251        return ERROR(corruption_detected);
 252    /* Validate that we haven't read beyond iend[].
 253        * Note that ip[] may be < iend[] because the MSB is
 254        * the next bit to read, and we may have consumed 100%
 255        * of the stream, so down to iend[i] - 8 is valid.
 256        */
 257    if (args->ip[stream] < args->iend[stream] - 8)
 258        return ERROR(corruption_detected);
 259
 260    /* Construct the BIT_DStream_t. */
 261    bit->bitContainer = MEM_readLE64(args->ip[stream]);
 262    bit->bitsConsumed = ZSTD_countTrailingZeros((size_t)args->bits[stream]);
 263    bit->start = (const char*)args->iend[0];
 264    bit->limitPtr = bit->start + sizeof(size_t);
 265    bit->ptr = (const char*)args->ip[stream];
 266
 267    return 0;
 268}
 269#endif
 270
 271
 272#ifndef HUF_FORCE_DECOMPRESS_X2
 273
 274/*-***************************/
 275/*  single-symbol decoding   */
 276/*-***************************/
 277typedef struct { BYTE nbBits; BYTE byte; } HUF_DEltX1;   /* single-symbol decoding */
 278
 279/*
 280 * Packs 4 HUF_DEltX1 structs into a U64. This is used to lay down 4 entries at
 281 * a time.
 282 */
 283static U64 HUF_DEltX1_set4(BYTE symbol, BYTE nbBits) {
 284    U64 D4;
 285    if (MEM_isLittleEndian()) {
 286        D4 = (symbol << 8) + nbBits;
 287    } else {
 288        D4 = symbol + (nbBits << 8);
 289    }
 290    D4 *= 0x0001000100010001ULL;
 291    return D4;
 292}
 293
 294/*
 295 * Increase the tableLog to targetTableLog and rescales the stats.
 296 * If tableLog > targetTableLog this is a no-op.
 297 * @returns New tableLog
 298 */
 299static U32 HUF_rescaleStats(BYTE* huffWeight, U32* rankVal, U32 nbSymbols, U32 tableLog, U32 targetTableLog)
 300{
 301    if (tableLog > targetTableLog)
 302        return tableLog;
 303    if (tableLog < targetTableLog) {
 304        U32 const scale = targetTableLog - tableLog;
 305        U32 s;
 306        /* Increase the weight for all non-zero probability symbols by scale. */
 307        for (s = 0; s < nbSymbols; ++s) {
 308            huffWeight[s] += (BYTE)((huffWeight[s] == 0) ? 0 : scale);
 309        }
 310        /* Update rankVal to reflect the new weights.
 311         * All weights except 0 get moved to weight + scale.
 312         * Weights [1, scale] are empty.
 313         */
 314        for (s = targetTableLog; s > scale; --s) {
 315            rankVal[s] = rankVal[s - scale];
 316        }
 317        for (s = scale; s > 0; --s) {
 318            rankVal[s] = 0;
 319        }
 320    }
 321    return targetTableLog;
 322}
 323
 324typedef struct {
 325        U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1];
 326        U32 rankStart[HUF_TABLELOG_ABSOLUTEMAX + 1];
 327        U32 statsWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
 328        BYTE symbols[HUF_SYMBOLVALUE_MAX + 1];
 329        BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1];
 330} HUF_ReadDTableX1_Workspace;
 331
 332
 333size_t HUF_readDTableX1_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize)
 334{
 335    return HUF_readDTableX1_wksp_bmi2(DTable, src, srcSize, workSpace, wkspSize, /* bmi2 */ 0);
 336}
 337
 338size_t HUF_readDTableX1_wksp_bmi2(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int bmi2)
 339{
 340    U32 tableLog = 0;
 341    U32 nbSymbols = 0;
 342    size_t iSize;
 343    void* const dtPtr = DTable + 1;
 344    HUF_DEltX1* const dt = (HUF_DEltX1*)dtPtr;
 345    HUF_ReadDTableX1_Workspace* wksp = (HUF_ReadDTableX1_Workspace*)workSpace;
 346
 347    DEBUG_STATIC_ASSERT(HUF_DECOMPRESS_WORKSPACE_SIZE >= sizeof(*wksp));
 348    if (sizeof(*wksp) > wkspSize) return ERROR(tableLog_tooLarge);
 349
 350    DEBUG_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUF_DTable));
 351    /* ZSTD_memset(huffWeight, 0, sizeof(huffWeight)); */   /* is not necessary, even though some analyzer complain ... */
 352
 353    iSize = HUF_readStats_wksp(wksp->huffWeight, HUF_SYMBOLVALUE_MAX + 1, wksp->rankVal, &nbSymbols, &tableLog, src, srcSize, wksp->statsWksp, sizeof(wksp->statsWksp), bmi2);
 354    if (HUF_isError(iSize)) return iSize;
 355
 356
 357    /* Table header */
 358    {   DTableDesc dtd = HUF_getDTableDesc(DTable);
 359        U32 const maxTableLog = dtd.maxTableLog + 1;
 360        U32 const targetTableLog = MIN(maxTableLog, HUF_DECODER_FAST_TABLELOG);
 361        tableLog = HUF_rescaleStats(wksp->huffWeight, wksp->rankVal, nbSymbols, tableLog, targetTableLog);
 362        if (tableLog > (U32)(dtd.maxTableLog+1)) return ERROR(tableLog_tooLarge);   /* DTable too small, Huffman tree cannot fit in */
 363        dtd.tableType = 0;
 364        dtd.tableLog = (BYTE)tableLog;
 365        ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
 366    }
 367
 368    /* Compute symbols and rankStart given rankVal:
 369     *
 370     * rankVal already contains the number of values of each weight.
 371     *
 372     * symbols contains the symbols ordered by weight. First are the rankVal[0]
 373     * weight 0 symbols, followed by the rankVal[1] weight 1 symbols, and so on.
 374     * symbols[0] is filled (but unused) to avoid a branch.
 375     *
 376     * rankStart contains the offset where each rank belongs in the DTable.
 377     * rankStart[0] is not filled because there are no entries in the table for
 378     * weight 0.
 379     */
 380    {
 381        int n;
 382        int nextRankStart = 0;
 383        int const unroll = 4;
 384        int const nLimit = (int)nbSymbols - unroll + 1;
 385        for (n=0; n<(int)tableLog+1; n++) {
 386            U32 const curr = nextRankStart;
 387            nextRankStart += wksp->rankVal[n];
 388            wksp->rankStart[n] = curr;
 389        }
 390        for (n=0; n < nLimit; n += unroll) {
 391            int u;
 392            for (u=0; u < unroll; ++u) {
 393                size_t const w = wksp->huffWeight[n+u];
 394                wksp->symbols[wksp->rankStart[w]++] = (BYTE)(n+u);
 395            }
 396        }
 397        for (; n < (int)nbSymbols; ++n) {
 398            size_t const w = wksp->huffWeight[n];
 399            wksp->symbols[wksp->rankStart[w]++] = (BYTE)n;
 400        }
 401    }
 402
 403    /* fill DTable
 404     * We fill all entries of each weight in order.
 405     * That way length is a constant for each iteration of the outer loop.
 406     * We can switch based on the length to a different inner loop which is
 407     * optimized for that particular case.
 408     */
 409    {
 410        U32 w;
 411        int symbol=wksp->rankVal[0];
 412        int rankStart=0;
 413        for (w=1; w<tableLog+1; ++w) {
 414            int const symbolCount = wksp->rankVal[w];
 415            int const length = (1 << w) >> 1;
 416            int uStart = rankStart;
 417            BYTE const nbBits = (BYTE)(tableLog + 1 - w);
 418            int s;
 419            int u;
 420            switch (length) {
 421            case 1:
 422                for (s=0; s<symbolCount; ++s) {
 423                    HUF_DEltX1 D;
 424                    D.byte = wksp->symbols[symbol + s];
 425                    D.nbBits = nbBits;
 426                    dt[uStart] = D;
 427                    uStart += 1;
 428                }
 429                break;
 430            case 2:
 431                for (s=0; s<symbolCount; ++s) {
 432                    HUF_DEltX1 D;
 433                    D.byte = wksp->symbols[symbol + s];
 434                    D.nbBits = nbBits;
 435                    dt[uStart+0] = D;
 436                    dt[uStart+1] = D;
 437                    uStart += 2;
 438                }
 439                break;
 440            case 4:
 441                for (s=0; s<symbolCount; ++s) {
 442                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
 443                    MEM_write64(dt + uStart, D4);
 444                    uStart += 4;
 445                }
 446                break;
 447            case 8:
 448                for (s=0; s<symbolCount; ++s) {
 449                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
 450                    MEM_write64(dt + uStart, D4);
 451                    MEM_write64(dt + uStart + 4, D4);
 452                    uStart += 8;
 453                }
 454                break;
 455            default:
 456                for (s=0; s<symbolCount; ++s) {
 457                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
 458                    for (u=0; u < length; u += 16) {
 459                        MEM_write64(dt + uStart + u + 0, D4);
 460                        MEM_write64(dt + uStart + u + 4, D4);
 461                        MEM_write64(dt + uStart + u + 8, D4);
 462                        MEM_write64(dt + uStart + u + 12, D4);
 463                    }
 464                    assert(u == length);
 465                    uStart += length;
 466                }
 467                break;
 468            }
 469            symbol += symbolCount;
 470            rankStart += symbolCount * length;
 471        }
 472    }
 473    return iSize;
 474}
 475
 476FORCE_INLINE_TEMPLATE BYTE
 477HUF_decodeSymbolX1(BIT_DStream_t* Dstream, const HUF_DEltX1* dt, const U32 dtLog)
 478{
 479    size_t const val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
 480    BYTE const c = dt[val].byte;
 481    BIT_skipBits(Dstream, dt[val].nbBits);
 482    return c;
 483}
 484
 485#define HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr) \
 486    *ptr++ = HUF_decodeSymbolX1(DStreamPtr, dt, dtLog)
 487
 488#define HUF_DECODE_SYMBOLX1_1(ptr, DStreamPtr)  \
 489    if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
 490        HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr)
 491
 492#define HUF_DECODE_SYMBOLX1_2(ptr, DStreamPtr) \
 493    if (MEM_64bits()) \
 494        HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr)
 495
 496HINT_INLINE size_t
 497HUF_decodeStreamX1(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, const HUF_DEltX1* const dt, const U32 dtLog)
 498{
 499    BYTE* const pStart = p;
 500
 501    /* up to 4 symbols at a time */
 502    if ((pEnd - p) > 3) {
 503        while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-3)) {
 504            HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
 505            HUF_DECODE_SYMBOLX1_1(p, bitDPtr);
 506            HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
 507            HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
 508        }
 509    } else {
 510        BIT_reloadDStream(bitDPtr);
 511    }
 512
 513    /* [0-3] symbols remaining */
 514    if (MEM_32bits())
 515        while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd))
 516            HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
 517
 518    /* no more data to retrieve from bitstream, no need to reload */
 519    while (p < pEnd)
 520        HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
 521
 522    return pEnd-pStart;
 523}
 524
 525FORCE_INLINE_TEMPLATE size_t
 526HUF_decompress1X1_usingDTable_internal_body(
 527          void* dst,  size_t dstSize,
 528    const void* cSrc, size_t cSrcSize,
 529    const HUF_DTable* DTable)
 530{
 531    BYTE* op = (BYTE*)dst;
 532    BYTE* const oend = op + dstSize;
 533    const void* dtPtr = DTable + 1;
 534    const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
 535    BIT_DStream_t bitD;
 536    DTableDesc const dtd = HUF_getDTableDesc(DTable);
 537    U32 const dtLog = dtd.tableLog;
 538
 539    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
 540
 541    HUF_decodeStreamX1(op, &bitD, oend, dt, dtLog);
 542
 543    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
 544
 545    return dstSize;
 546}
 547
 548FORCE_INLINE_TEMPLATE size_t
 549HUF_decompress4X1_usingDTable_internal_body(
 550          void* dst,  size_t dstSize,
 551    const void* cSrc, size_t cSrcSize,
 552    const HUF_DTable* DTable)
 553{
 554    /* Check */
 555    if (cSrcSize < 10) return ERROR(corruption_detected);  /* strict minimum : jump table + 1 byte per stream */
 556
 557    {   const BYTE* const istart = (const BYTE*) cSrc;
 558        BYTE* const ostart = (BYTE*) dst;
 559        BYTE* const oend = ostart + dstSize;
 560        BYTE* const olimit = oend - 3;
 561        const void* const dtPtr = DTable + 1;
 562        const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
 563
 564        /* Init */
 565        BIT_DStream_t bitD1;
 566        BIT_DStream_t bitD2;
 567        BIT_DStream_t bitD3;
 568        BIT_DStream_t bitD4;
 569        size_t const length1 = MEM_readLE16(istart);
 570        size_t const length2 = MEM_readLE16(istart+2);
 571        size_t const length3 = MEM_readLE16(istart+4);
 572        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
 573        const BYTE* const istart1 = istart + 6;  /* jumpTable */
 574        const BYTE* const istart2 = istart1 + length1;
 575        const BYTE* const istart3 = istart2 + length2;
 576        const BYTE* const istart4 = istart3 + length3;
 577        const size_t segmentSize = (dstSize+3) / 4;
 578        BYTE* const opStart2 = ostart + segmentSize;
 579        BYTE* const opStart3 = opStart2 + segmentSize;
 580        BYTE* const opStart4 = opStart3 + segmentSize;
 581        BYTE* op1 = ostart;
 582        BYTE* op2 = opStart2;
 583        BYTE* op3 = opStart3;
 584        BYTE* op4 = opStart4;
 585        DTableDesc const dtd = HUF_getDTableDesc(DTable);
 586        U32 const dtLog = dtd.tableLog;
 587        U32 endSignal = 1;
 588
 589        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
 590        if (opStart4 > oend) return ERROR(corruption_detected);      /* overflow */
 591        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
 592        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
 593        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
 594        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
 595
 596        /* up to 16 symbols per loop (4 symbols per stream) in 64-bit mode */
 597        if ((size_t)(oend - op4) >= sizeof(size_t)) {
 598            for ( ; (endSignal) & (op4 < olimit) ; ) {
 599                HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
 600                HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
 601                HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
 602                HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
 603                HUF_DECODE_SYMBOLX1_1(op1, &bitD1);
 604                HUF_DECODE_SYMBOLX1_1(op2, &bitD2);
 605                HUF_DECODE_SYMBOLX1_1(op3, &bitD3);
 606                HUF_DECODE_SYMBOLX1_1(op4, &bitD4);
 607                HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
 608                HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
 609                HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
 610                HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
 611                HUF_DECODE_SYMBOLX1_0(op1, &bitD1);
 612                HUF_DECODE_SYMBOLX1_0(op2, &bitD2);
 613                HUF_DECODE_SYMBOLX1_0(op3, &bitD3);
 614                HUF_DECODE_SYMBOLX1_0(op4, &bitD4);
 615                endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
 616                endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
 617                endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
 618                endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
 619            }
 620        }
 621
 622        /* check corruption */
 623        /* note : should not be necessary : op# advance in lock step, and we control op4.
 624         *        but curiously, binary generated by gcc 7.2 & 7.3 with -mbmi2 runs faster when >=1 test is present */
 625        if (op1 > opStart2) return ERROR(corruption_detected);
 626        if (op2 > opStart3) return ERROR(corruption_detected);
 627        if (op3 > opStart4) return ERROR(corruption_detected);
 628        /* note : op4 supposed already verified within main loop */
 629
 630        /* finish bitStreams one by one */
 631        HUF_decodeStreamX1(op1, &bitD1, opStart2, dt, dtLog);
 632        HUF_decodeStreamX1(op2, &bitD2, opStart3, dt, dtLog);
 633        HUF_decodeStreamX1(op3, &bitD3, opStart4, dt, dtLog);
 634        HUF_decodeStreamX1(op4, &bitD4, oend,     dt, dtLog);
 635
 636        /* check */
 637        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
 638          if (!endCheck) return ERROR(corruption_detected); }
 639
 640        /* decoded size */
 641        return dstSize;
 642    }
 643}
 644
 645#if HUF_NEED_BMI2_FUNCTION
 646static BMI2_TARGET_ATTRIBUTE
 647size_t HUF_decompress4X1_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
 648                    size_t cSrcSize, HUF_DTable const* DTable) {
 649    return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
 650}
 651#endif
 652
 653#if HUF_NEED_DEFAULT_FUNCTION
 654static
 655size_t HUF_decompress4X1_usingDTable_internal_default(void* dst, size_t dstSize, void const* cSrc,
 656                    size_t cSrcSize, HUF_DTable const* DTable) {
 657    return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
 658}
 659#endif
 660
 661#if ZSTD_ENABLE_ASM_X86_64_BMI2
 662
 663HUF_ASM_DECL void HUF_decompress4X1_usingDTable_internal_bmi2_asm_loop(HUF_DecompressAsmArgs* args) ZSTDLIB_HIDDEN;
 664
 665static HUF_ASM_X86_64_BMI2_ATTRS
 666size_t
 667HUF_decompress4X1_usingDTable_internal_bmi2_asm(
 668          void* dst,  size_t dstSize,
 669    const void* cSrc, size_t cSrcSize,
 670    const HUF_DTable* DTable)
 671{
 672    void const* dt = DTable + 1;
 673    const BYTE* const iend = (const BYTE*)cSrc + 6;
 674    BYTE* const oend = (BYTE*)dst + dstSize;
 675    HUF_DecompressAsmArgs args;
 676    {
 677        size_t const ret = HUF_DecompressAsmArgs_init(&args, dst, dstSize, cSrc, cSrcSize, DTable);
 678        FORWARD_IF_ERROR(ret, "Failed to init asm args");
 679        if (ret != 0)
 680            return HUF_decompress4X1_usingDTable_internal_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);
 681    }
 682
 683    assert(args.ip[0] >= args.ilimit);
 684    HUF_decompress4X1_usingDTable_internal_bmi2_asm_loop(&args);
 685
 686    /* Our loop guarantees that ip[] >= ilimit and that we haven't
 687    * overwritten any op[].
 688    */
 689    assert(args.ip[0] >= iend);
 690    assert(args.ip[1] >= iend);
 691    assert(args.ip[2] >= iend);
 692    assert(args.ip[3] >= iend);
 693    assert(args.op[3] <= oend);
 694    (void)iend;
 695
 696    /* finish bit streams one by one. */
 697    {
 698        size_t const segmentSize = (dstSize+3) / 4;
 699        BYTE* segmentEnd = (BYTE*)dst;
 700        int i;
 701        for (i = 0; i < 4; ++i) {
 702            BIT_DStream_t bit;
 703            if (segmentSize <= (size_t)(oend - segmentEnd))
 704                segmentEnd += segmentSize;
 705            else
 706                segmentEnd = oend;
 707            FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
 708            /* Decompress and validate that we've produced exactly the expected length. */
 709            args.op[i] += HUF_decodeStreamX1(args.op[i], &bit, segmentEnd, (HUF_DEltX1 const*)dt, HUF_DECODER_FAST_TABLELOG);
 710            if (args.op[i] != segmentEnd) return ERROR(corruption_detected);
 711        }
 712    }
 713
 714    /* decoded size */
 715    return dstSize;
 716}
 717#endif /* ZSTD_ENABLE_ASM_X86_64_BMI2 */
 718
 719typedef size_t (*HUF_decompress_usingDTable_t)(void *dst, size_t dstSize,
 720                                               const void *cSrc,
 721                                               size_t cSrcSize,
 722                                               const HUF_DTable *DTable);
 723
 724HUF_DGEN(HUF_decompress1X1_usingDTable_internal)
 725
 726static size_t HUF_decompress4X1_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
 727                    size_t cSrcSize, HUF_DTable const* DTable, int bmi2)
 728{
 729#if DYNAMIC_BMI2
 730    if (bmi2) {
 731# if ZSTD_ENABLE_ASM_X86_64_BMI2
 732        return HUF_decompress4X1_usingDTable_internal_bmi2_asm(dst, dstSize, cSrc, cSrcSize, DTable);
 733# else
 734        return HUF_decompress4X1_usingDTable_internal_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);
 735# endif
 736    }
 737#else
 738    (void)bmi2;
 739#endif
 740
 741#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
 742    return HUF_decompress4X1_usingDTable_internal_bmi2_asm(dst, dstSize, cSrc, cSrcSize, DTable);
 743#else
 744    return HUF_decompress4X1_usingDTable_internal_default(dst, dstSize, cSrc, cSrcSize, DTable);
 745#endif
 746}
 747
 748
 749size_t HUF_decompress1X1_usingDTable(
 750          void* dst,  size_t dstSize,
 751    const void* cSrc, size_t cSrcSize,
 752    const HUF_DTable* DTable)
 753{
 754    DTableDesc dtd = HUF_getDTableDesc(DTable);
 755    if (dtd.tableType != 0) return ERROR(GENERIC);
 756    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
 757}
 758
 759size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
 760                                   const void* cSrc, size_t cSrcSize,
 761                                   void* workSpace, size_t wkspSize)
 762{
 763    const BYTE* ip = (const BYTE*) cSrc;
 764
 765    size_t const hSize = HUF_readDTableX1_wksp(DCtx, cSrc, cSrcSize, workSpace, wkspSize);
 766    if (HUF_isError(hSize)) return hSize;
 767    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
 768    ip += hSize; cSrcSize -= hSize;
 769
 770    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
 771}
 772
 773
 774size_t HUF_decompress4X1_usingDTable(
 775          void* dst,  size_t dstSize,
 776    const void* cSrc, size_t cSrcSize,
 777    const HUF_DTable* DTable)
 778{
 779    DTableDesc dtd = HUF_getDTableDesc(DTable);
 780    if (dtd.tableType != 0) return ERROR(GENERIC);
 781    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
 782}
 783
 784static size_t HUF_decompress4X1_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
 785                                   const void* cSrc, size_t cSrcSize,
 786                                   void* workSpace, size_t wkspSize, int bmi2)
 787{
 788    const BYTE* ip = (const BYTE*) cSrc;
 789
 790    size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
 791    if (HUF_isError(hSize)) return hSize;
 792    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
 793    ip += hSize; cSrcSize -= hSize;
 794
 795    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
 796}
 797
 798size_t HUF_decompress4X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
 799                                   const void* cSrc, size_t cSrcSize,
 800                                   void* workSpace, size_t wkspSize)
 801{
 802    return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, 0);
 803}
 804
 805
 806#endif /* HUF_FORCE_DECOMPRESS_X2 */
 807
 808
 809#ifndef HUF_FORCE_DECOMPRESS_X1
 810
 811/* *************************/
 812/* double-symbols decoding */
 813/* *************************/
 814
 815typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX2;  /* double-symbols decoding */
 816typedef struct { BYTE symbol; } sortedSymbol_t;
 817typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
 818typedef rankValCol_t rankVal_t[HUF_TABLELOG_MAX];
 819
 820/*
 821 * Constructs a HUF_DEltX2 in a U32.
 822 */
 823static U32 HUF_buildDEltX2U32(U32 symbol, U32 nbBits, U32 baseSeq, int level)
 824{
 825    U32 seq;
 826    DEBUG_STATIC_ASSERT(offsetof(HUF_DEltX2, sequence) == 0);
 827    DEBUG_STATIC_ASSERT(offsetof(HUF_DEltX2, nbBits) == 2);
 828    DEBUG_STATIC_ASSERT(offsetof(HUF_DEltX2, length) == 3);
 829    DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(U32));
 830    if (MEM_isLittleEndian()) {
 831        seq = level == 1 ? symbol : (baseSeq + (symbol << 8));
 832        return seq + (nbBits << 16) + ((U32)level << 24);
 833    } else {
 834        seq = level == 1 ? (symbol << 8) : ((baseSeq << 8) + symbol);
 835        return (seq << 16) + (nbBits << 8) + (U32)level;
 836    }
 837}
 838
 839/*
 840 * Constructs a HUF_DEltX2.
 841 */
 842static HUF_DEltX2 HUF_buildDEltX2(U32 symbol, U32 nbBits, U32 baseSeq, int level)
 843{
 844    HUF_DEltX2 DElt;
 845    U32 const val = HUF_buildDEltX2U32(symbol, nbBits, baseSeq, level);
 846    DEBUG_STATIC_ASSERT(sizeof(DElt) == sizeof(val));
 847    ZSTD_memcpy(&DElt, &val, sizeof(val));
 848    return DElt;
 849}
 850
 851/*
 852 * Constructs 2 HUF_DEltX2s and packs them into a U64.
 853 */
 854static U64 HUF_buildDEltX2U64(U32 symbol, U32 nbBits, U16 baseSeq, int level)
 855{
 856    U32 DElt = HUF_buildDEltX2U32(symbol, nbBits, baseSeq, level);
 857    return (U64)DElt + ((U64)DElt << 32);
 858}
 859
 860/*
 861 * Fills the DTable rank with all the symbols from [begin, end) that are each
 862 * nbBits long.
 863 *
 864 * @param DTableRank The start of the rank in the DTable.
 865 * @param begin The first symbol to fill (inclusive).
 866 * @param end The last symbol to fill (exclusive).
 867 * @param nbBits Each symbol is nbBits long.
 868 * @param tableLog The table log.
 869 * @param baseSeq If level == 1 { 0 } else { the first level symbol }
 870 * @param level The level in the table. Must be 1 or 2.
 871 */
 872static void HUF_fillDTableX2ForWeight(
 873    HUF_DEltX2* DTableRank,
 874    sortedSymbol_t const* begin, sortedSymbol_t const* end,
 875    U32 nbBits, U32 tableLog,
 876    U16 baseSeq, int const level)
 877{
 878    U32 const length = 1U << ((tableLog - nbBits) & 0x1F /* quiet static-analyzer */);
 879    const sortedSymbol_t* ptr;
 880    assert(level >= 1 && level <= 2);
 881    switch (length) {
 882    case 1:
 883        for (ptr = begin; ptr != end; ++ptr) {
 884            HUF_DEltX2 const DElt = HUF_buildDEltX2(ptr->symbol, nbBits, baseSeq, level);
 885            *DTableRank++ = DElt;
 886        }
 887        break;
 888    case 2:
 889        for (ptr = begin; ptr != end; ++ptr) {
 890            HUF_DEltX2 const DElt = HUF_buildDEltX2(ptr->symbol, nbBits, baseSeq, level);
 891            DTableRank[0] = DElt;
 892            DTableRank[1] = DElt;
 893            DTableRank += 2;
 894        }
 895        break;
 896    case 4:
 897        for (ptr = begin; ptr != end; ++ptr) {
 898            U64 const DEltX2 = HUF_buildDEltX2U64(ptr->symbol, nbBits, baseSeq, level);
 899            ZSTD_memcpy(DTableRank + 0, &DEltX2, sizeof(DEltX2));
 900            ZSTD_memcpy(DTableRank + 2, &DEltX2, sizeof(DEltX2));
 901            DTableRank += 4;
 902        }
 903        break;
 904    case 8:
 905        for (ptr = begin; ptr != end; ++ptr) {
 906            U64 const DEltX2 = HUF_buildDEltX2U64(ptr->symbol, nbBits, baseSeq, level);
 907            ZSTD_memcpy(DTableRank + 0, &DEltX2, sizeof(DEltX2));
 908            ZSTD_memcpy(DTableRank + 2, &DEltX2, sizeof(DEltX2));
 909            ZSTD_memcpy(DTableRank + 4, &DEltX2, sizeof(DEltX2));
 910            ZSTD_memcpy(DTableRank + 6, &DEltX2, sizeof(DEltX2));
 911            DTableRank += 8;
 912        }
 913        break;
 914    default:
 915        for (ptr = begin; ptr != end; ++ptr) {
 916            U64 const DEltX2 = HUF_buildDEltX2U64(ptr->symbol, nbBits, baseSeq, level);
 917            HUF_DEltX2* const DTableRankEnd = DTableRank + length;
 918            for (; DTableRank != DTableRankEnd; DTableRank += 8) {
 919                ZSTD_memcpy(DTableRank + 0, &DEltX2, sizeof(DEltX2));
 920                ZSTD_memcpy(DTableRank + 2, &DEltX2, sizeof(DEltX2));
 921                ZSTD_memcpy(DTableRank + 4, &DEltX2, sizeof(DEltX2));
 922                ZSTD_memcpy(DTableRank + 6, &DEltX2, sizeof(DEltX2));
 923            }
 924        }
 925        break;
 926    }
 927}
 928
 929/* HUF_fillDTableX2Level2() :
 930 * `rankValOrigin` must be a table of at least (HUF_TABLELOG_MAX + 1) U32 */
 931static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 targetLog, const U32 consumedBits,
 932                           const U32* rankVal, const int minWeight, const int maxWeight1,
 933                           const sortedSymbol_t* sortedSymbols, U32 const* rankStart,
 934                           U32 nbBitsBaseline, U16 baseSeq)
 935{
 936    /* Fill skipped values (all positions up to rankVal[minWeight]).
 937     * These are positions only get a single symbol because the combined weight
 938     * is too large.
 939     */
 940    if (minWeight>1) {
 941        U32 const length = 1U << ((targetLog - consumedBits) & 0x1F /* quiet static-analyzer */);
 942        U64 const DEltX2 = HUF_buildDEltX2U64(baseSeq, consumedBits, /* baseSeq */ 0, /* level */ 1);
 943        int const skipSize = rankVal[minWeight];
 944        assert(length > 1);
 945        assert((U32)skipSize < length);
 946        switch (length) {
 947        case 2:
 948            assert(skipSize == 1);
 949            ZSTD_memcpy(DTable, &DEltX2, sizeof(DEltX2));
 950            break;
 951        case 4:
 952            assert(skipSize <= 4);
 953            ZSTD_memcpy(DTable + 0, &DEltX2, sizeof(DEltX2));
 954            ZSTD_memcpy(DTable + 2, &DEltX2, sizeof(DEltX2));
 955            break;
 956        default:
 957            {
 958                int i;
 959                for (i = 0; i < skipSize; i += 8) {
 960                    ZSTD_memcpy(DTable + i + 0, &DEltX2, sizeof(DEltX2));
 961                    ZSTD_memcpy(DTable + i + 2, &DEltX2, sizeof(DEltX2));
 962                    ZSTD_memcpy(DTable + i + 4, &DEltX2, sizeof(DEltX2));
 963                    ZSTD_memcpy(DTable + i + 6, &DEltX2, sizeof(DEltX2));
 964                }
 965            }
 966        }
 967    }
 968
 969    /* Fill each of the second level symbols by weight. */
 970    {
 971        int w;
 972        for (w = minWeight; w < maxWeight1; ++w) {
 973            int const begin = rankStart[w];
 974            int const end = rankStart[w+1];
 975            U32 const nbBits = nbBitsBaseline - w;
 976            U32 const totalBits = nbBits + consumedBits;
 977            HUF_fillDTableX2ForWeight(
 978                DTable + rankVal[w],
 979                sortedSymbols + begin, sortedSymbols + end,
 980                totalBits, targetLog,
 981                baseSeq, /* level */ 2);
 982        }
 983    }
 984}
 985
 986static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
 987                           const sortedSymbol_t* sortedList,
 988                           const U32* rankStart, rankValCol_t *rankValOrigin, const U32 maxWeight,
 989                           const U32 nbBitsBaseline)
 990{
 991    U32* const rankVal = rankValOrigin[0];
 992    const int scaleLog = nbBitsBaseline - targetLog;   /* note : targetLog >= srcLog, hence scaleLog <= 1 */
 993    const U32 minBits  = nbBitsBaseline - maxWeight;
 994    int w;
 995    int const wEnd = (int)maxWeight + 1;
 996
 997    /* Fill DTable in order of weight. */
 998    for (w = 1; w < wEnd; ++w) {
 999        int const begin = (int)rankStart[w];
1000        int const end = (int)rankStart[w+1];
1001        U32 const nbBits = nbBitsBaseline - w;
1002
1003        if (targetLog-nbBits >= minBits) {
1004            /* Enough room for a second symbol. */
1005            int start = rankVal[w];
1006            U32 const length = 1U << ((targetLog - nbBits) & 0x1F /* quiet static-analyzer */);
1007            int minWeight = nbBits + scaleLog;
1008            int s;
1009            if (minWeight < 1) minWeight = 1;
1010            /* Fill the DTable for every symbol of weight w.
1011             * These symbols get at least 1 second symbol.
1012             */
1013            for (s = begin; s != end; ++s) {
1014                HUF_fillDTableX2Level2(
1015                    DTable + start, targetLog, nbBits,
1016                    rankValOrigin[nbBits], minWeight, wEnd,
1017                    sortedList, rankStart,
1018                    nbBitsBaseline, sortedList[s].symbol);
1019                start += length;
1020            }
1021        } else {
1022            /* Only a single symbol. */
1023            HUF_fillDTableX2ForWeight(
1024                DTable + rankVal[w],
1025                sortedList + begin, sortedList + end,
1026                nbBits, targetLog,
1027                /* baseSeq */ 0, /* level */ 1);
1028        }
1029    }
1030}
1031
1032typedef struct {
1033    rankValCol_t rankVal[HUF_TABLELOG_MAX];
1034    U32 rankStats[HUF_TABLELOG_MAX + 1];
1035    U32 rankStart0[HUF_TABLELOG_MAX + 3];
1036    sortedSymbol_t sortedSymbol[HUF_SYMBOLVALUE_MAX + 1];
1037    BYTE weightList[HUF_SYMBOLVALUE_MAX + 1];
1038    U32 calleeWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
1039} HUF_ReadDTableX2_Workspace;
1040
1041size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
1042                       const void* src, size_t srcSize,
1043                             void* workSpace, size_t wkspSize)
1044{
1045    return HUF_readDTableX2_wksp_bmi2(DTable, src, srcSize, workSpace, wkspSize, /* bmi2 */ 0);
1046}
1047
1048size_t HUF_readDTableX2_wksp_bmi2(HUF_DTable* DTable,
1049                       const void* src, size_t srcSize,
1050                             void* workSpace, size_t wkspSize, int bmi2)
1051{
1052    U32 tableLog, maxW, nbSymbols;
1053    DTableDesc dtd = HUF_getDTableDesc(DTable);
1054    U32 maxTableLog = dtd.maxTableLog;
1055    size_t iSize;
1056    void* dtPtr = DTable+1;   /* force compiler to avoid strict-aliasing */
1057    HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
1058    U32 *rankStart;
1059
1060    HUF_ReadDTableX2_Workspace* const wksp = (HUF_ReadDTableX2_Workspace*)workSpace;
1061
1062    if (sizeof(*wksp) > wkspSize) return ERROR(GENERIC);
1063
1064    rankStart = wksp->rankStart0 + 1;
1065    ZSTD_memset(wksp->rankStats, 0, sizeof(wksp->rankStats));
1066    ZSTD_memset(wksp->rankStart0, 0, sizeof(wksp->rankStart0));
1067
1068    DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(HUF_DTable));   /* if compiler fails here, assertion is wrong */
1069    if (maxTableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
1070    /* ZSTD_memset(weightList, 0, sizeof(weightList)); */  /* is not necessary, even though some analyzer complain ... */
1071
1072    iSize = HUF_readStats_wksp(wksp->weightList, HUF_SYMBOLVALUE_MAX + 1, wksp->rankStats, &nbSymbols, &tableLog, src, srcSize, wksp->calleeWksp, sizeof(wksp->calleeWksp), bmi2);
1073    if (HUF_isError(iSize)) return iSize;
1074
1075    /* check result */
1076    if (tableLog > maxTableLog) return ERROR(tableLog_tooLarge);   /* DTable can't fit code depth */
1077    if (tableLog <= HUF_DECODER_FAST_TABLELOG && maxTableLog > HUF_DECODER_FAST_TABLELOG) maxTableLog = HUF_DECODER_FAST_TABLELOG;
1078
1079    /* find maxWeight */
1080    for (maxW = tableLog; wksp->rankStats[maxW]==0; maxW--) {}  /* necessarily finds a solution before 0 */
1081
1082    /* Get start index of each weight */
1083    {   U32 w, nextRankStart = 0;
1084        for (w=1; w<maxW+1; w++) {
1085            U32 curr = nextRankStart;
1086            nextRankStart += wksp->rankStats[w];
1087            rankStart[w] = curr;
1088        }
1089        rankStart[0] = nextRankStart;   /* put all 0w symbols at the end of sorted list*/
1090        rankStart[maxW+1] = nextRankStart;
1091    }
1092
1093    /* sort symbols by weight */
1094    {   U32 s;
1095        for (s=0; s<nbSymbols; s++) {
1096            U32 const w = wksp->weightList[s];
1097            U32 const r = rankStart[w]++;
1098            wksp->sortedSymbol[r].symbol = (BYTE)s;
1099        }
1100        rankStart[0] = 0;   /* forget 0w symbols; this is beginning of weight(1) */
1101    }
1102
1103    /* Build rankVal */
1104    {   U32* const rankVal0 = wksp->rankVal[0];
1105        {   int const rescale = (maxTableLog-tableLog) - 1;   /* tableLog <= maxTableLog */
1106            U32 nextRankVal = 0;
1107            U32 w;
1108            for (w=1; w<maxW+1; w++) {
1109                U32 curr = nextRankVal;
1110                nextRankVal += wksp->rankStats[w] << (w+rescale);
1111                rankVal0[w] = curr;
1112        }   }
1113        {   U32 const minBits = tableLog+1 - maxW;
1114            U32 consumed;
1115            for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
1116                U32* const rankValPtr = wksp->rankVal[consumed];
1117                U32 w;
1118                for (w = 1; w < maxW+1; w++) {
1119                    rankValPtr[w] = rankVal0[w] >> consumed;
1120    }   }   }   }
1121
1122    HUF_fillDTableX2(dt, maxTableLog,
1123                   wksp->sortedSymbol,
1124                   wksp->rankStart0, wksp->rankVal, maxW,
1125                   tableLog+1);
1126
1127    dtd.tableLog = (BYTE)maxTableLog;
1128    dtd.tableType = 1;
1129    ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
1130    return iSize;
1131}
1132
1133
1134FORCE_INLINE_TEMPLATE U32
1135HUF_decodeSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
1136{
1137    size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
1138    ZSTD_memcpy(op, &dt[val].sequence, 2);
1139    BIT_skipBits(DStream, dt[val].nbBits);
1140    return dt[val].length;
1141}
1142
1143FORCE_INLINE_TEMPLATE U32
1144HUF_decodeLastSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
1145{
1146    size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
1147    ZSTD_memcpy(op, &dt[val].sequence, 1);
1148    if (dt[val].length==1) {
1149        BIT_skipBits(DStream, dt[val].nbBits);
1150    } else {
1151        if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8)) {
1152            BIT_skipBits(DStream, dt[val].nbBits);
1153            if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
1154                /* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
1155                DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);
1156        }
1157    }
1158    return 1;
1159}
1160
1161#define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
1162    ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
1163
1164#define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
1165    if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
1166        ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
1167
1168#define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
1169    if (MEM_64bits()) \
1170        ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
1171
1172HINT_INLINE size_t
1173HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd,
1174                const HUF_DEltX2* const dt, const U32 dtLog)
1175{
1176    BYTE* const pStart = p;
1177
1178    /* up to 8 symbols at a time */
1179    if ((size_t)(pEnd - p) >= sizeof(bitDPtr->bitContainer)) {
1180        if (dtLog <= 11 && MEM_64bits()) {
1181            /* up to 10 symbols at a time */
1182            while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-9)) {
1183                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1184                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1185                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1186                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1187                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1188            }
1189        } else {
1190            /* up to 8 symbols at a time */
1191            while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-(sizeof(bitDPtr->bitContainer)-1))) {
1192                HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
1193                HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
1194                HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
1195                HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1196            }
1197        }
1198    } else {
1199        BIT_reloadDStream(bitDPtr);
1200    }
1201
1202    /* closer to end : up to 2 symbols at a time */
1203    if ((size_t)(pEnd - p) >= 2) {
1204        while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd-2))
1205            HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1206
1207        while (p <= pEnd-2)
1208            HUF_DECODE_SYMBOLX2_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
1209    }
1210
1211    if (p < pEnd)
1212        p += HUF_decodeLastSymbolX2(p, bitDPtr, dt, dtLog);
1213
1214    return p-pStart;
1215}
1216
1217FORCE_INLINE_TEMPLATE size_t
1218HUF_decompress1X2_usingDTable_internal_body(
1219          void* dst,  size_t dstSize,
1220    const void* cSrc, size_t cSrcSize,
1221    const HUF_DTable* DTable)
1222{
1223    BIT_DStream_t bitD;
1224
1225    /* Init */
1226    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
1227
1228    /* decode */
1229    {   BYTE* const ostart = (BYTE*) dst;
1230        BYTE* const oend = ostart + dstSize;
1231        const void* const dtPtr = DTable+1;   /* force compiler to not use strict-aliasing */
1232        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
1233        DTableDesc const dtd = HUF_getDTableDesc(DTable);
1234        HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
1235    }
1236
1237    /* check */
1238    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
1239
1240    /* decoded size */
1241    return dstSize;
1242}
1243FORCE_INLINE_TEMPLATE size_t
1244HUF_decompress4X2_usingDTable_internal_body(
1245          void* dst,  size_t dstSize,
1246    const void* cSrc, size_t cSrcSize,
1247    const HUF_DTable* DTable)
1248{
1249    if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
1250
1251    {   const BYTE* const istart = (const BYTE*) cSrc;
1252        BYTE* const ostart = (BYTE*) dst;
1253        BYTE* const oend = ostart + dstSize;
1254        BYTE* const olimit = oend - (sizeof(size_t)-1);
1255        const void* const dtPtr = DTable+1;
1256        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
1257
1258        /* Init */
1259        BIT_DStream_t bitD1;
1260        BIT_DStream_t bitD2;
1261        BIT_DStream_t bitD3;
1262        BIT_DStream_t bitD4;
1263        size_t const length1 = MEM_readLE16(istart);
1264        size_t const length2 = MEM_readLE16(istart+2);
1265        size_t const length3 = MEM_readLE16(istart+4);
1266        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
1267        const BYTE* const istart1 = istart + 6;  /* jumpTable */
1268        const BYTE* const istart2 = istart1 + length1;
1269        const BYTE* const istart3 = istart2 + length2;
1270        const BYTE* const istart4 = istart3 + length3;
1271        size_t const segmentSize = (dstSize+3) / 4;
1272        BYTE* const opStart2 = ostart + segmentSize;
1273        BYTE* const opStart3 = opStart2 + segmentSize;
1274        BYTE* const opStart4 = opStart3 + segmentSize;
1275        BYTE* op1 = ostart;
1276        BYTE* op2 = opStart2;
1277        BYTE* op3 = opStart3;
1278        BYTE* op4 = opStart4;
1279        U32 endSignal = 1;
1280        DTableDesc const dtd = HUF_getDTableDesc(DTable);
1281        U32 const dtLog = dtd.tableLog;
1282
1283        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
1284        if (opStart4 > oend) return ERROR(corruption_detected);      /* overflow */
1285        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
1286        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
1287        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
1288        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
1289
1290        /* 16-32 symbols per loop (4-8 symbols per stream) */
1291        if ((size_t)(oend - op4) >= sizeof(size_t)) {
1292            for ( ; (endSignal) & (op4 < olimit); ) {
1293#if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
1294                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
1295                HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
1296                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
1297                HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
1298                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
1299                HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
1300                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
1301                HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
1302                endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
1303                endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
1304                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
1305                HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
1306                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
1307                HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
1308                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
1309                HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
1310                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
1311                HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
1312                endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
1313                endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
1314#else
1315                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
1316                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
1317                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
1318                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
1319                HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
1320                HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
1321                HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
1322                HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
1323                HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
1324                HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
1325                HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
1326                HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
1327                HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
1328                HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
1329                HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
1330                HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
1331                endSignal = (U32)LIKELY((U32)
1332                            (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
1333                        & (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
1334                        & (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)
1335                        & (BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished));
1336#endif
1337            }
1338        }
1339
1340        /* check corruption */
1341        if (op1 > opStart2) return ERROR(corruption_detected);
1342        if (op2 > opStart3) return ERROR(corruption_detected);
1343        if (op3 > opStart4) return ERROR(corruption_detected);
1344        /* note : op4 already verified within main loop */
1345
1346        /* finish bitStreams one by one */
1347        HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
1348        HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
1349        HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
1350        HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);
1351
1352        /* check */
1353        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
1354          if (!endCheck) return ERROR(corruption_detected); }
1355
1356        /* decoded size */
1357        return dstSize;
1358    }
1359}
1360
1361#if HUF_NEED_BMI2_FUNCTION
1362static BMI2_TARGET_ATTRIBUTE
1363size_t HUF_decompress4X2_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
1364                    size_t cSrcSize, HUF_DTable const* DTable) {
1365    return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
1366}
1367#endif
1368
1369#if HUF_NEED_DEFAULT_FUNCTION
1370static
1371size_t HUF_decompress4X2_usingDTable_internal_default(void* dst, size_t dstSize, void const* cSrc,
1372                    size_t cSrcSize, HUF_DTable const* DTable) {
1373    return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
1374}
1375#endif
1376
1377#if ZSTD_ENABLE_ASM_X86_64_BMI2
1378
1379HUF_ASM_DECL void HUF_decompress4X2_usingDTable_internal_bmi2_asm_loop(HUF_DecompressAsmArgs* args) ZSTDLIB_HIDDEN;
1380
1381static HUF_ASM_X86_64_BMI2_ATTRS size_t
1382HUF_decompress4X2_usingDTable_internal_bmi2_asm(
1383          void* dst,  size_t dstSize,
1384    const void* cSrc, size_t cSrcSize,
1385    const HUF_DTable* DTable) {
1386    void const* dt = DTable + 1;
1387    const BYTE* const iend = (const BYTE*)cSrc + 6;
1388    BYTE* const oend = (BYTE*)dst + dstSize;
1389    HUF_DecompressAsmArgs args;
1390    {
1391        size_t const ret = HUF_DecompressAsmArgs_init(&args, dst, dstSize, cSrc, cSrcSize, DTable);
1392        FORWARD_IF_ERROR(ret, "Failed to init asm args");
1393        if (ret != 0)
1394            return HUF_decompress4X2_usingDTable_internal_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);
1395    }
1396
1397    assert(args.ip[0] >= args.ilimit);
1398    HUF_decompress4X2_usingDTable_internal_bmi2_asm_loop(&args);
1399
1400    /* note : op4 already verified within main loop */
1401    assert(args.ip[0] >= iend);
1402    assert(args.ip[1] >= iend);
1403    assert(args.ip[2] >= iend);
1404    assert(args.ip[3] >= iend);
1405    assert(args.op[3] <= oend);
1406    (void)iend;
1407
1408    /* finish bitStreams one by one */
1409    {
1410        size_t const segmentSize = (dstSize+3) / 4;
1411        BYTE* segmentEnd = (BYTE*)dst;
1412        int i;
1413        for (i = 0; i < 4; ++i) {
1414            BIT_DStream_t bit;
1415            if (segmentSize <= (size_t)(oend - segmentEnd))
1416                segmentEnd += segmentSize;
1417            else
1418                segmentEnd = oend;
1419            FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
1420            args.op[i] += HUF_decodeStreamX2(args.op[i], &bit, segmentEnd, (HUF_DEltX2 const*)dt, HUF_DECODER_FAST_TABLELOG);
1421            if (args.op[i] != segmentEnd)
1422                return ERROR(corruption_detected);
1423        }
1424    }
1425
1426    /* decoded size */
1427    return dstSize;
1428}
1429#endif /* ZSTD_ENABLE_ASM_X86_64_BMI2 */
1430
1431static size_t HUF_decompress4X2_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
1432                    size_t cSrcSize, HUF_DTable const* DTable, int bmi2)
1433{
1434#if DYNAMIC_BMI2
1435    if (bmi2) {
1436# if ZSTD_ENABLE_ASM_X86_64_BMI2
1437        return HUF_decompress4X2_usingDTable_internal_bmi2_asm(dst, dstSize, cSrc, cSrcSize, DTable);
1438# else
1439        return HUF_decompress4X2_usingDTable_internal_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);
1440# endif
1441    }
1442#else
1443    (void)bmi2;
1444#endif
1445
1446#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
1447    return HUF_decompress4X2_usingDTable_internal_bmi2_asm(dst, dstSize, cSrc, cSrcSize, DTable);
1448#else
1449    return HUF_decompress4X2_usingDTable_internal_default(dst, dstSize, cSrc, cSrcSize, DTable);
1450#endif
1451}
1452
1453HUF_DGEN(HUF_decompress1X2_usingDTable_internal)
1454
1455size_t HUF_decompress1X2_usingDTable(
1456          void* dst,  size_t dstSize,
1457    const void* cSrc, size_t cSrcSize,
1458    const HUF_DTable* DTable)
1459{
1460    DTableDesc dtd = HUF_getDTableDesc(DTable);
1461    if (dtd.tableType != 1) return ERROR(GENERIC);
1462    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1463}
1464
1465size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
1466                                   const void* cSrc, size_t cSrcSize,
1467                                   void* workSpace, size_t wkspSize)
1468{
1469    const BYTE* ip = (const BYTE*) cSrc;
1470
1471    size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize,
1472                                               workSpace, wkspSize);
1473    if (HUF_isError(hSize)) return hSize;
1474    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
1475    ip += hSize; cSrcSize -= hSize;
1476
1477    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
1478}
1479
1480
1481size_t HUF_decompress4X2_usingDTable(
1482          void* dst,  size_t dstSize,
1483    const void* cSrc, size_t cSrcSize,
1484    const HUF_DTable* DTable)
1485{
1486    DTableDesc dtd = HUF_getDTableDesc(DTable);
1487    if (dtd.tableType != 1) return ERROR(GENERIC);
1488    return HUF_decompress4X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1489}
1490
1491static size_t HUF_decompress4X2_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
1492                                   const void* cSrc, size_t cSrcSize,
1493                                   void* workSpace, size_t wkspSize, int bmi2)
1494{
1495    const BYTE* ip = (const BYTE*) cSrc;
1496
1497    size_t hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize,
1498                                         workSpace, wkspSize);
1499    if (HUF_isError(hSize)) return hSize;
1500    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
1501    ip += hSize; cSrcSize -= hSize;
1502
1503    return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
1504}
1505
1506size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
1507                                   const void* cSrc, size_t cSrcSize,
1508                                   void* workSpace, size_t wkspSize)
1509{
1510    return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, /* bmi2 */ 0);
1511}
1512
1513
1514#endif /* HUF_FORCE_DECOMPRESS_X1 */
1515
1516
1517/* ***********************************/
1518/* Universal decompression selectors */
1519/* ***********************************/
1520
1521size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize,
1522                                    const void* cSrc, size_t cSrcSize,
1523                                    const HUF_DTable* DTable)
1524{
1525    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1526#if defined(HUF_FORCE_DECOMPRESS_X1)
1527    (void)dtd;
1528    assert(dtd.tableType == 0);
1529    return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1530#elif defined(HUF_FORCE_DECOMPRESS_X2)
1531    (void)dtd;
1532    assert(dtd.tableType == 1);
1533    return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1534#else
1535    return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
1536                           HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1537#endif
1538}
1539
1540size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize,
1541                                    const void* cSrc, size_t cSrcSize,
1542                                    const HUF_DTable* DTable)
1543{
1544    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1545#if defined(HUF_FORCE_DECOMPRESS_X1)
1546    (void)dtd;
1547    assert(dtd.tableType == 0);
1548    return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1549#elif defined(HUF_FORCE_DECOMPRESS_X2)
1550    (void)dtd;
1551    assert(dtd.tableType == 1);
1552    return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1553#else
1554    return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
1555                           HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1556#endif
1557}
1558
1559
1560#if !defined(HUF_FORCE_DECOMPRESS_X1) && !defined(HUF_FORCE_DECOMPRESS_X2)
1561typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
1562static const algo_time_t algoTime[16 /* Quantization */][2 /* single, double */] =
1563{
1564    /* single, double, quad */
1565    {{0,0}, {1,1}},  /* Q==0 : impossible */
1566    {{0,0}, {1,1}},  /* Q==1 : impossible */
1567    {{ 150,216}, { 381,119}},   /* Q == 2 : 12-18% */
1568    {{ 170,205}, { 514,112}},   /* Q == 3 : 18-25% */
1569    {{ 177,199}, { 539,110}},   /* Q == 4 : 25-32% */
1570    {{ 197,194}, { 644,107}},   /* Q == 5 : 32-38% */
1571    {{ 221,192}, { 735,107}},   /* Q == 6 : 38-44% */
1572    {{ 256,189}, { 881,106}},   /* Q == 7 : 44-50% */
1573    {{ 359,188}, {1167,109}},   /* Q == 8 : 50-56% */
1574    {{ 582,187}, {1570,114}},   /* Q == 9 : 56-62% */
1575    {{ 688,187}, {1712,122}},   /* Q ==10 : 62-69% */
1576    {{ 825,186}, {1965,136}},   /* Q ==11 : 69-75% */
1577    {{ 976,185}, {2131,150}},   /* Q ==12 : 75-81% */
1578    {{1180,186}, {2070,175}},   /* Q ==13 : 81-87% */
1579    {{1377,185}, {1731,202}},   /* Q ==14 : 87-93% */
1580    {{1412,185}, {1695,202}},   /* Q ==15 : 93-99% */
1581};
1582#endif
1583
1584/* HUF_selectDecoder() :
1585 *  Tells which decoder is likely to decode faster,
1586 *  based on a set of pre-computed metrics.
1587 * @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
1588 *  Assumption : 0 < dstSize <= 128 KB */
1589U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize)
1590{
1591    assert(dstSize > 0);
1592    assert(dstSize <= 128*1024);
1593#if defined(HUF_FORCE_DECOMPRESS_X1)
1594    (void)dstSize;
1595    (void)cSrcSize;
1596    return 0;
1597#elif defined(HUF_FORCE_DECOMPRESS_X2)
1598    (void)dstSize;
1599    (void)cSrcSize;
1600    return 1;
1601#else
1602    /* decoder timing evaluation */
1603    {   U32 const Q = (cSrcSize >= dstSize) ? 15 : (U32)(cSrcSize * 16 / dstSize);   /* Q < 16 */
1604        U32 const D256 = (U32)(dstSize >> 8);
1605        U32 const DTime0 = algoTime[Q][0].tableTime + (algoTime[Q][0].decode256Time * D256);
1606        U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * D256);
1607        DTime1 += DTime1 >> 5;  /* small advantage to algorithm using less memory, to reduce cache eviction */
1608        return DTime1 < DTime0;
1609    }
1610#endif
1611}
1612
1613
1614size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst,
1615                                     size_t dstSize, const void* cSrc,
1616                                     size_t cSrcSize, void* workSpace,
1617                                     size_t wkspSize)
1618{
1619    /* validation checks */
1620    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1621    if (cSrcSize == 0) return ERROR(corruption_detected);
1622
1623    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1624#if defined(HUF_FORCE_DECOMPRESS_X1)
1625        (void)algoNb;
1626        assert(algoNb == 0);
1627        return HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1628#elif defined(HUF_FORCE_DECOMPRESS_X2)
1629        (void)algoNb;
1630        assert(algoNb == 1);
1631        return HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1632#else
1633        return algoNb ? HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1634                            cSrcSize, workSpace, wkspSize):
1635                        HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1636#endif
1637    }
1638}
1639
1640size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
1641                                  const void* cSrc, size_t cSrcSize,
1642                                  void* workSpace, size_t wkspSize)
1643{
1644    /* validation checks */
1645    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1646    if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
1647    if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
1648    if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
1649
1650    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1651#if defined(HUF_FORCE_DECOMPRESS_X1)
1652        (void)algoNb;
1653        assert(algoNb == 0);
1654        return HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
1655                                cSrcSize, workSpace, wkspSize);
1656#elif defined(HUF_FORCE_DECOMPRESS_X2)
1657        (void)algoNb;
1658        assert(algoNb == 1);
1659        return HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1660                                cSrcSize, workSpace, wkspSize);
1661#else
1662        return algoNb ? HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1663                                cSrcSize, workSpace, wkspSize):
1664                        HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
1665                                cSrcSize, workSpace, wkspSize);
1666#endif
1667    }
1668}
1669
1670
1671size_t HUF_decompress1X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
1672{
1673    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1674#if defined(HUF_FORCE_DECOMPRESS_X1)
1675    (void)dtd;
1676    assert(dtd.tableType == 0);
1677    return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1678#elif defined(HUF_FORCE_DECOMPRESS_X2)
1679    (void)dtd;
1680    assert(dtd.tableType == 1);
1681    return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1682#else
1683    return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
1684                           HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1685#endif
1686}
1687
1688#ifndef HUF_FORCE_DECOMPRESS_X2
1689size_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)
1690{
1691    const BYTE* ip = (const BYTE*) cSrc;
1692
1693    size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1694    if (HUF_isError(hSize)) return hSize;
1695    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
1696    ip += hSize; cSrcSize -= hSize;
1697
1698    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
1699}
1700#endif
1701
1702size_t HUF_decompress4X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
1703{
1704    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1705#if defined(HUF_FORCE_DECOMPRESS_X1)
1706    (void)dtd;
1707    assert(dtd.tableType == 0);
1708    return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1709#elif defined(HUF_FORCE_DECOMPRESS_X2)
1710    (void)dtd;
1711    assert(dtd.tableType == 1);
1712    return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1713#else
1714    return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
1715                           HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1716#endif
1717}
1718
1719size_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)
1720{
1721    /* validation checks */
1722    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1723    if (cSrcSize == 0) return ERROR(corruption_detected);
1724
1725    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1726#if defined(HUF_FORCE_DECOMPRESS_X1)
1727        (void)algoNb;
1728        assert(algoNb == 0);
1729        return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1730#elif defined(HUF_FORCE_DECOMPRESS_X2)
1731        (void)algoNb;
1732        assert(algoNb == 1);
1733        return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1734#else
1735        return algoNb ? HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2) :
1736                        HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1737#endif
1738    }
1739}
1740