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
1741