1/* ******************************************************************
2 * huff0 huffman decoder,
3 * part of Finite State Entropy library
4 * Copyright (c) 2013-2020, Yann Collet, Facebook, Inc.
5 *
6 *  You can contact the author at :
7 *  - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
8 *
9 * This source code is licensed under both the BSD-style license (found in the
10 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
11 * in the COPYING file in the root directory of this source tree).
12 * You may select, at your option, one of the above-listed licenses.
13****************************************************************** */
14
15/* **************************************************************
16*  Dependencies
17****************************************************************/
18#include "../common/zstd_deps.h"  /* ZSTD_memcpy, ZSTD_memset */
19#include "../common/compiler.h"
20#include "../common/bitstream.h"  /* BIT_* */
21#include "../common/fse.h"        /* to compress headers */
22#define HUF_STATIC_LINKING_ONLY
23#include "../common/huf.h"
24#include "../common/error_private.h"
25
26/* **************************************************************
27*  Macros
28****************************************************************/
29
30/* These two optional macros force the use one way or another of the two
31 * Huffman decompression implementations. You can't force in both directions
32 * at the same time.
33 */
34#if defined(HUF_FORCE_DECOMPRESS_X1) && \
35    defined(HUF_FORCE_DECOMPRESS_X2)
36#error "Cannot force the use of the X1 and X2 decoders at the same time!"
37#endif
38
39
40/* **************************************************************
41*  Error Management
42****************************************************************/
43#define HUF_isError ERR_isError
44
45
46/* **************************************************************
47*  Byte alignment for workSpace management
48****************************************************************/
49#define HUF_ALIGN(x, a)         HUF_ALIGN_MASK((x), (a) - 1)
50#define HUF_ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
51
52
53/* **************************************************************
54*  BMI2 Variant Wrappers
55****************************************************************/
56#if DYNAMIC_BMI2
57
58#define HUF_DGEN(fn)                                                        \
59                                                                            \
60    static size_t fn##_default(                                             \
61                  void* dst,  size_t dstSize,                               \
62            const void* cSrc, size_t cSrcSize,                              \
63            const HUF_DTable* DTable)                                       \
64    {                                                                       \
65        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
66    }                                                                       \
67                                                                            \
68    static TARGET_ATTRIBUTE("bmi2") size_t fn##_bmi2(                       \
69                  void* dst,  size_t dstSize,                               \
70            const void* cSrc, size_t cSrcSize,                              \
71            const HUF_DTable* DTable)                                       \
72    {                                                                       \
73        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
74    }                                                                       \
75                                                                            \
76    static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
77                     size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
78    {                                                                       \
79        if (bmi2) {                                                         \
80            return fn##_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);         \
81        }                                                                   \
82        return fn##_default(dst, dstSize, cSrc, cSrcSize, DTable);          \
83    }
84
85#else
86
87#define HUF_DGEN(fn)                                                        \
88    static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
89                     size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
90    {                                                                       \
91        (void)bmi2;                                                         \
92        return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
93    }
94
95#endif
96
97
98/*-***************************/
99/*  generic DTableDesc       */
100/*-***************************/
101typedef struct { BYTE maxTableLog; BYTE tableType; BYTE tableLog; BYTE reserved; } DTableDesc;
102
103static DTableDesc HUF_getDTableDesc(const HUF_DTable* table)
104{
105    DTableDesc dtd;
106    ZSTD_memcpy(&dtd, table, sizeof(dtd));
107    return dtd;
108}
109
110
111#ifndef HUF_FORCE_DECOMPRESS_X2
112
113/*-***************************/
114/*  single-symbol decoding   */
115/*-***************************/
116typedef struct { BYTE byte; BYTE nbBits; } HUF_DEltX1;   /* single-symbol decoding */
117
118/**
119 * Packs 4 HUF_DEltX1 structs into a U64. This is used to lay down 4 entries at
120 * a time.
121 */
122static U64 HUF_DEltX1_set4(BYTE symbol, BYTE nbBits) {
123    U64 D4;
124    if (MEM_isLittleEndian()) {
125        D4 = symbol + (nbBits << 8);
126    } else {
127        D4 = (symbol << 8) + nbBits;
128    }
129    D4 *= 0x0001000100010001ULL;
130    return D4;
131}
132
133typedef struct {
134        U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1];
135        U32 rankStart[HUF_TABLELOG_ABSOLUTEMAX + 1];
136        U32 statsWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
137        BYTE symbols[HUF_SYMBOLVALUE_MAX + 1];
138        BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1];
139} HUF_ReadDTableX1_Workspace;
140
141
142size_t HUF_readDTableX1_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize)
143{
144    return HUF_readDTableX1_wksp_bmi2(DTable, src, srcSize, workSpace, wkspSize, /* bmi2 */ 0);
145}
146
147size_t HUF_readDTableX1_wksp_bmi2(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int bmi2)
148{
149    U32 tableLog = 0;
150    U32 nbSymbols = 0;
151    size_t iSize;
152    void* const dtPtr = DTable + 1;
153    HUF_DEltX1* const dt = (HUF_DEltX1*)dtPtr;
154    HUF_ReadDTableX1_Workspace* wksp = (HUF_ReadDTableX1_Workspace*)workSpace;
155
156    DEBUG_STATIC_ASSERT(HUF_DECOMPRESS_WORKSPACE_SIZE >= sizeof(*wksp));
157    if (sizeof(*wksp) > wkspSize) return ERROR(tableLog_tooLarge);
158
159    DEBUG_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUF_DTable));
160    /* ZSTD_memset(huffWeight, 0, sizeof(huffWeight)); */   /* is not necessary, even though some analyzer complain ... */
161
162    iSize = HUF_readStats_wksp(wksp->huffWeight, HUF_SYMBOLVALUE_MAX + 1, wksp->rankVal, &nbSymbols, &tableLog, src, srcSize, wksp->statsWksp, sizeof(wksp->statsWksp), bmi2);
163    if (HUF_isError(iSize)) return iSize;
164
165    /* Table header */
166    {   DTableDesc dtd = HUF_getDTableDesc(DTable);
167        if (tableLog > (U32)(dtd.maxTableLog+1)) return ERROR(tableLog_tooLarge);   /* DTable too small, Huffman tree cannot fit in */
168        dtd.tableType = 0;
169        dtd.tableLog = (BYTE)tableLog;
170        ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
171    }
172
173    /* Compute symbols and rankStart given rankVal:
174     *
175     * rankVal already contains the number of values of each weight.
176     *
177     * symbols contains the symbols ordered by weight. First are the rankVal[0]
178     * weight 0 symbols, followed by the rankVal[1] weight 1 symbols, and so on.
179     * symbols[0] is filled (but unused) to avoid a branch.
180     *
181     * rankStart contains the offset where each rank belongs in the DTable.
182     * rankStart[0] is not filled because there are no entries in the table for
183     * weight 0.
184     */
185    {
186        int n;
187        int nextRankStart = 0;
188        int const unroll = 4;
189        int const nLimit = (int)nbSymbols - unroll + 1;
190        for (n=0; n<(int)tableLog+1; n++) {
191            U32 const curr = nextRankStart;
192            nextRankStart += wksp->rankVal[n];
193            wksp->rankStart[n] = curr;
194        }
195        for (n=0; n < nLimit; n += unroll) {
196            int u;
197            for (u=0; u < unroll; ++u) {
198                size_t const w = wksp->huffWeight[n+u];
199                wksp->symbols[wksp->rankStart[w]++] = (BYTE)(n+u);
200            }
201        }
202        for (; n < (int)nbSymbols; ++n) {
203            size_t const w = wksp->huffWeight[n];
204            wksp->symbols[wksp->rankStart[w]++] = (BYTE)n;
205        }
206    }
207
208    /* fill DTable
209     * We fill all entries of each weight in order.
210     * That way length is a constant for each iteration of the outter loop.
211     * We can switch based on the length to a different inner loop which is
212     * optimized for that particular case.
213     */
214    {
215        U32 w;
216        int symbol=wksp->rankVal[0];
217        int rankStart=0;
218        for (w=1; w<tableLog+1; ++w) {
219            int const symbolCount = wksp->rankVal[w];
220            int const length = (1 << w) >> 1;
221            int uStart = rankStart;
222            BYTE const nbBits = (BYTE)(tableLog + 1 - w);
223            int s;
224            int u;
225            switch (length) {
226            case 1:
227                for (s=0; s<symbolCount; ++s) {
228                    HUF_DEltX1 D;
229                    D.byte = wksp->symbols[symbol + s];
230                    D.nbBits = nbBits;
231                    dt[uStart] = D;
232                    uStart += 1;
233                }
234                break;
235            case 2:
236                for (s=0; s<symbolCount; ++s) {
237                    HUF_DEltX1 D;
238                    D.byte = wksp->symbols[symbol + s];
239                    D.nbBits = nbBits;
240                    dt[uStart+0] = D;
241                    dt[uStart+1] = D;
242                    uStart += 2;
243                }
244                break;
245            case 4:
246                for (s=0; s<symbolCount; ++s) {
247                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
248                    MEM_write64(dt + uStart, D4);
249                    uStart += 4;
250                }
251                break;
252            case 8:
253                for (s=0; s<symbolCount; ++s) {
254                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
255                    MEM_write64(dt + uStart, D4);
256                    MEM_write64(dt + uStart + 4, D4);
257                    uStart += 8;
258                }
259                break;
260            default:
261                for (s=0; s<symbolCount; ++s) {
262                    U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
263                    for (u=0; u < length; u += 16) {
264                        MEM_write64(dt + uStart + u + 0, D4);
265                        MEM_write64(dt + uStart + u + 4, D4);
266                        MEM_write64(dt + uStart + u + 8, D4);
267                        MEM_write64(dt + uStart + u + 12, D4);
268                    }
269                    assert(u == length);
270                    uStart += length;
271                }
272                break;
273            }
274            symbol += symbolCount;
275            rankStart += symbolCount * length;
276        }
277    }
278    return iSize;
279}
280
281FORCE_INLINE_TEMPLATE BYTE
282HUF_decodeSymbolX1(BIT_DStream_t* Dstream, const HUF_DEltX1* dt, const U32 dtLog)
283{
284    size_t const val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
285    BYTE const c = dt[val].byte;
286    BIT_skipBits(Dstream, dt[val].nbBits);
287    return c;
288}
289
290#define HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr) \
291    *ptr++ = HUF_decodeSymbolX1(DStreamPtr, dt, dtLog)
292
293#define HUF_DECODE_SYMBOLX1_1(ptr, DStreamPtr)  \
294    if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
295        HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr)
296
297#define HUF_DECODE_SYMBOLX1_2(ptr, DStreamPtr) \
298    if (MEM_64bits()) \
299        HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr)
300
301HINT_INLINE size_t
302HUF_decodeStreamX1(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, const HUF_DEltX1* const dt, const U32 dtLog)
303{
304    BYTE* const pStart = p;
305
306    /* up to 4 symbols at a time */
307    while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-3)) {
308        HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
309        HUF_DECODE_SYMBOLX1_1(p, bitDPtr);
310        HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
311        HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
312    }
313
314    /* [0-3] symbols remaining */
315    if (MEM_32bits())
316        while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd))
317            HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
318
319    /* no more data to retrieve from bitstream, no need to reload */
320    while (p < pEnd)
321        HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
322
323    return pEnd-pStart;
324}
325
326FORCE_INLINE_TEMPLATE size_t
327HUF_decompress1X1_usingDTable_internal_body(
328          void* dst,  size_t dstSize,
329    const void* cSrc, size_t cSrcSize,
330    const HUF_DTable* DTable)
331{
332    BYTE* op = (BYTE*)dst;
333    BYTE* const oend = op + dstSize;
334    const void* dtPtr = DTable + 1;
335    const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
336    BIT_DStream_t bitD;
337    DTableDesc const dtd = HUF_getDTableDesc(DTable);
338    U32 const dtLog = dtd.tableLog;
339
340    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
341
342    HUF_decodeStreamX1(op, &bitD, oend, dt, dtLog);
343
344    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
345
346    return dstSize;
347}
348
349FORCE_INLINE_TEMPLATE size_t
350HUF_decompress4X1_usingDTable_internal_body(
351          void* dst,  size_t dstSize,
352    const void* cSrc, size_t cSrcSize,
353    const HUF_DTable* DTable)
354{
355    /* Check */
356    if (cSrcSize < 10) return ERROR(corruption_detected);  /* strict minimum : jump table + 1 byte per stream */
357
358    {   const BYTE* const istart = (const BYTE*) cSrc;
359        BYTE* const ostart = (BYTE*) dst;
360        BYTE* const oend = ostart + dstSize;
361        BYTE* const olimit = oend - 3;
362        const void* const dtPtr = DTable + 1;
363        const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
364
365        /* Init */
366        BIT_DStream_t bitD1;
367        BIT_DStream_t bitD2;
368        BIT_DStream_t bitD3;
369        BIT_DStream_t bitD4;
370        size_t const length1 = MEM_readLE16(istart);
371        size_t const length2 = MEM_readLE16(istart+2);
372        size_t const length3 = MEM_readLE16(istart+4);
373        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
374        const BYTE* const istart1 = istart + 6;  /* jumpTable */
375        const BYTE* const istart2 = istart1 + length1;
376        const BYTE* const istart3 = istart2 + length2;
377        const BYTE* const istart4 = istart3 + length3;
378        const size_t segmentSize = (dstSize+3) / 4;
379        BYTE* const opStart2 = ostart + segmentSize;
380        BYTE* const opStart3 = opStart2 + segmentSize;
381        BYTE* const opStart4 = opStart3 + segmentSize;
382        BYTE* op1 = ostart;
383        BYTE* op2 = opStart2;
384        BYTE* op3 = opStart3;
385        BYTE* op4 = opStart4;
386        DTableDesc const dtd = HUF_getDTableDesc(DTable);
387        U32 const dtLog = dtd.tableLog;
388        U32 endSignal = 1;
389
390        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
391        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
392        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
393        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
394        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
395
396        /* up to 16 symbols per loop (4 symbols per stream) in 64-bit mode */
397        for ( ; (endSignal) & (op4 < olimit) ; ) {
398            HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
399            HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
400            HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
401            HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
402            HUF_DECODE_SYMBOLX1_1(op1, &bitD1);
403            HUF_DECODE_SYMBOLX1_1(op2, &bitD2);
404            HUF_DECODE_SYMBOLX1_1(op3, &bitD3);
405            HUF_DECODE_SYMBOLX1_1(op4, &bitD4);
406            HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
407            HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
408            HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
409            HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
410            HUF_DECODE_SYMBOLX1_0(op1, &bitD1);
411            HUF_DECODE_SYMBOLX1_0(op2, &bitD2);
412            HUF_DECODE_SYMBOLX1_0(op3, &bitD3);
413            HUF_DECODE_SYMBOLX1_0(op4, &bitD4);
414            endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
415            endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
416            endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
417            endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
418        }
419
420        /* check corruption */
421        /* note : should not be necessary : op# advance in lock step, and we control op4.
422         *        but curiously, binary generated by gcc 7.2 & 7.3 with -mbmi2 runs faster when >=1 test is present */
423        if (op1 > opStart2) return ERROR(corruption_detected);
424        if (op2 > opStart3) return ERROR(corruption_detected);
425        if (op3 > opStart4) return ERROR(corruption_detected);
426        /* note : op4 supposed already verified within main loop */
427
428        /* finish bitStreams one by one */
429        HUF_decodeStreamX1(op1, &bitD1, opStart2, dt, dtLog);
430        HUF_decodeStreamX1(op2, &bitD2, opStart3, dt, dtLog);
431        HUF_decodeStreamX1(op3, &bitD3, opStart4, dt, dtLog);
432        HUF_decodeStreamX1(op4, &bitD4, oend,     dt, dtLog);
433
434        /* check */
435        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
436          if (!endCheck) return ERROR(corruption_detected); }
437
438        /* decoded size */
439        return dstSize;
440    }
441}
442
443
444typedef size_t (*HUF_decompress_usingDTable_t)(void *dst, size_t dstSize,
445                                               const void *cSrc,
446                                               size_t cSrcSize,
447                                               const HUF_DTable *DTable);
448
449HUF_DGEN(HUF_decompress1X1_usingDTable_internal)
450HUF_DGEN(HUF_decompress4X1_usingDTable_internal)
451
452
453
454size_t HUF_decompress1X1_usingDTable(
455          void* dst,  size_t dstSize,
456    const void* cSrc, size_t cSrcSize,
457    const HUF_DTable* DTable)
458{
459    DTableDesc dtd = HUF_getDTableDesc(DTable);
460    if (dtd.tableType != 0) return ERROR(GENERIC);
461    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
462}
463
464size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
465                                   const void* cSrc, size_t cSrcSize,
466                                   void* workSpace, size_t wkspSize)
467{
468    const BYTE* ip = (const BYTE*) cSrc;
469
470    size_t const hSize = HUF_readDTableX1_wksp(DCtx, cSrc, cSrcSize, workSpace, wkspSize);
471    if (HUF_isError(hSize)) return hSize;
472    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
473    ip += hSize; cSrcSize -= hSize;
474
475    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
476}
477
478
479size_t HUF_decompress4X1_usingDTable(
480          void* dst,  size_t dstSize,
481    const void* cSrc, size_t cSrcSize,
482    const HUF_DTable* DTable)
483{
484    DTableDesc dtd = HUF_getDTableDesc(DTable);
485    if (dtd.tableType != 0) return ERROR(GENERIC);
486    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
487}
488
489static size_t HUF_decompress4X1_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
490                                   const void* cSrc, size_t cSrcSize,
491                                   void* workSpace, size_t wkspSize, int bmi2)
492{
493    const BYTE* ip = (const BYTE*) cSrc;
494
495    size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
496    if (HUF_isError(hSize)) return hSize;
497    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
498    ip += hSize; cSrcSize -= hSize;
499
500    return HUF_decompress4X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
501}
502
503size_t HUF_decompress4X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
504                                   const void* cSrc, size_t cSrcSize,
505                                   void* workSpace, size_t wkspSize)
506{
507    return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, 0);
508}
509
510
511#endif /* HUF_FORCE_DECOMPRESS_X2 */
512
513
514#ifndef HUF_FORCE_DECOMPRESS_X1
515
516/* *************************/
517/* double-symbols decoding */
518/* *************************/
519
520typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX2;  /* double-symbols decoding */
521typedef struct { BYTE symbol; BYTE weight; } sortedSymbol_t;
522typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
523typedef rankValCol_t rankVal_t[HUF_TABLELOG_MAX];
524
525
526/* HUF_fillDTableX2Level2() :
527 * `rankValOrigin` must be a table of at least (HUF_TABLELOG_MAX + 1) U32 */
528static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 sizeLog, const U32 consumed,
529                           const U32* rankValOrigin, const int minWeight,
530                           const sortedSymbol_t* sortedSymbols, const U32 sortedListSize,
531                           U32 nbBitsBaseline, U16 baseSeq)
532{
533    HUF_DEltX2 DElt;
534    U32 rankVal[HUF_TABLELOG_MAX + 1];
535
536    /* get pre-calculated rankVal */
537    ZSTD_memcpy(rankVal, rankValOrigin, sizeof(rankVal));
538
539    /* fill skipped values */
540    if (minWeight>1) {
541        U32 i, skipSize = rankVal[minWeight];
542        MEM_writeLE16(&(DElt.sequence), baseSeq);
543        DElt.nbBits   = (BYTE)(consumed);
544        DElt.length   = 1;
545        for (i = 0; i < skipSize; i++)
546            DTable[i] = DElt;
547    }
548
549    /* fill DTable */
550    {   U32 s; for (s=0; s<sortedListSize; s++) {   /* note : sortedSymbols already skipped */
551            const U32 symbol = sortedSymbols[s].symbol;
552            const U32 weight = sortedSymbols[s].weight;
553            const U32 nbBits = nbBitsBaseline - weight;
554            const U32 length = 1 << (sizeLog-nbBits);
555            const U32 start = rankVal[weight];
556            U32 i = start;
557            const U32 end = start + length;
558
559            MEM_writeLE16(&(DElt.sequence), (U16)(baseSeq + (symbol << 8)));
560            DElt.nbBits = (BYTE)(nbBits + consumed);
561            DElt.length = 2;
562            do { DTable[i++] = DElt; } while (i<end);   /* since length >= 1 */
563
564            rankVal[weight] += length;
565    }   }
566}
567
568
569static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
570                           const sortedSymbol_t* sortedList, const U32 sortedListSize,
571                           const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
572                           const U32 nbBitsBaseline)
573{
574    U32 rankVal[HUF_TABLELOG_MAX + 1];
575    const int scaleLog = nbBitsBaseline - targetLog;   /* note : targetLog >= srcLog, hence scaleLog <= 1 */
576    const U32 minBits  = nbBitsBaseline - maxWeight;
577    U32 s;
578
579    ZSTD_memcpy(rankVal, rankValOrigin, sizeof(rankVal));
580
581    /* fill DTable */
582    for (s=0; s<sortedListSize; s++) {
583        const U16 symbol = sortedList[s].symbol;
584        const U32 weight = sortedList[s].weight;
585        const U32 nbBits = nbBitsBaseline - weight;
586        const U32 start = rankVal[weight];
587        const U32 length = 1 << (targetLog-nbBits);
588
589        if (targetLog-nbBits >= minBits) {   /* enough room for a second symbol */
590            U32 sortedRank;
591            int minWeight = nbBits + scaleLog;
592            if (minWeight < 1) minWeight = 1;
593            sortedRank = rankStart[minWeight];
594            HUF_fillDTableX2Level2(DTable+start, targetLog-nbBits, nbBits,
595                           rankValOrigin[nbBits], minWeight,
596                           sortedList+sortedRank, sortedListSize-sortedRank,
597                           nbBitsBaseline, symbol);
598        } else {
599            HUF_DEltX2 DElt;
600            MEM_writeLE16(&(DElt.sequence), symbol);
601            DElt.nbBits = (BYTE)(nbBits);
602            DElt.length = 1;
603            {   U32 const end = start + length;
604                U32 u;
605                for (u = start; u < end; u++) DTable[u] = DElt;
606        }   }
607        rankVal[weight] += length;
608    }
609}
610
611size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
612                       const void* src, size_t srcSize,
613                             void* workSpace, size_t wkspSize)
614{
615    U32 tableLog, maxW, sizeOfSort, nbSymbols;
616    DTableDesc dtd = HUF_getDTableDesc(DTable);
617    U32 const maxTableLog = dtd.maxTableLog;
618    size_t iSize;
619    void* dtPtr = DTable+1;   /* force compiler to avoid strict-aliasing */
620    HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
621    U32 *rankStart;
622
623    rankValCol_t* rankVal;
624    U32* rankStats;
625    U32* rankStart0;
626    sortedSymbol_t* sortedSymbol;
627    BYTE* weightList;
628    size_t spaceUsed32 = 0;
629
630    rankVal = (rankValCol_t *)((U32 *)workSpace + spaceUsed32);
631    spaceUsed32 += (sizeof(rankValCol_t) * HUF_TABLELOG_MAX) >> 2;
632    rankStats = (U32 *)workSpace + spaceUsed32;
633    spaceUsed32 += HUF_TABLELOG_MAX + 1;
634    rankStart0 = (U32 *)workSpace + spaceUsed32;
635    spaceUsed32 += HUF_TABLELOG_MAX + 2;
636    sortedSymbol = (sortedSymbol_t *)workSpace + (spaceUsed32 * sizeof(U32)) / sizeof(sortedSymbol_t);
637    spaceUsed32 += HUF_ALIGN(sizeof(sortedSymbol_t) * (HUF_SYMBOLVALUE_MAX + 1), sizeof(U32)) >> 2;
638    weightList = (BYTE *)((U32 *)workSpace + spaceUsed32);
639    spaceUsed32 += HUF_ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2;
640
641    if ((spaceUsed32 << 2) > wkspSize) return ERROR(tableLog_tooLarge);
642
643    rankStart = rankStart0 + 1;
644    ZSTD_memset(rankStats, 0, sizeof(U32) * (2 * HUF_TABLELOG_MAX + 2 + 1));
645
646    DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(HUF_DTable));   /* if compiler fails here, assertion is wrong */
647    if (maxTableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
648    /* ZSTD_memset(weightList, 0, sizeof(weightList)); */  /* is not necessary, even though some analyzer complain ... */
649
650    iSize = HUF_readStats(weightList, HUF_SYMBOLVALUE_MAX + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
651    if (HUF_isError(iSize)) return iSize;
652
653    /* check result */
654    if (tableLog > maxTableLog) return ERROR(tableLog_tooLarge);   /* DTable can't fit code depth */
655
656    /* find maxWeight */
657    for (maxW = tableLog; rankStats[maxW]==0; maxW--) {}  /* necessarily finds a solution before 0 */
658
659    /* Get start index of each weight */
660    {   U32 w, nextRankStart = 0;
661        for (w=1; w<maxW+1; w++) {
662            U32 curr = nextRankStart;
663            nextRankStart += rankStats[w];
664            rankStart[w] = curr;
665        }
666        rankStart[0] = nextRankStart;   /* put all 0w symbols at the end of sorted list*/
667        sizeOfSort = nextRankStart;
668    }
669
670    /* sort symbols by weight */
671    {   U32 s;
672        for (s=0; s<nbSymbols; s++) {
673            U32 const w = weightList[s];
674            U32 const r = rankStart[w]++;
675            sortedSymbol[r].symbol = (BYTE)s;
676            sortedSymbol[r].weight = (BYTE)w;
677        }
678        rankStart[0] = 0;   /* forget 0w symbols; this is beginning of weight(1) */
679    }
680
681    /* Build rankVal */
682    {   U32* const rankVal0 = rankVal[0];
683        {   int const rescale = (maxTableLog-tableLog) - 1;   /* tableLog <= maxTableLog */
684            U32 nextRankVal = 0;
685            U32 w;
686            for (w=1; w<maxW+1; w++) {
687                U32 curr = nextRankVal;
688                nextRankVal += rankStats[w] << (w+rescale);
689                rankVal0[w] = curr;
690        }   }
691        {   U32 const minBits = tableLog+1 - maxW;
692            U32 consumed;
693            for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
694                U32* const rankValPtr = rankVal[consumed];
695                U32 w;
696                for (w = 1; w < maxW+1; w++) {
697                    rankValPtr[w] = rankVal0[w] >> consumed;
698    }   }   }   }
699
700    HUF_fillDTableX2(dt, maxTableLog,
701                   sortedSymbol, sizeOfSort,
702                   rankStart0, rankVal, maxW,
703                   tableLog+1);
704
705    dtd.tableLog = (BYTE)maxTableLog;
706    dtd.tableType = 1;
707    ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
708    return iSize;
709}
710
711
712FORCE_INLINE_TEMPLATE U32
713HUF_decodeSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
714{
715    size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
716    ZSTD_memcpy(op, dt+val, 2);
717    BIT_skipBits(DStream, dt[val].nbBits);
718    return dt[val].length;
719}
720
721FORCE_INLINE_TEMPLATE U32
722HUF_decodeLastSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
723{
724    size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
725    ZSTD_memcpy(op, dt+val, 1);
726    if (dt[val].length==1) BIT_skipBits(DStream, dt[val].nbBits);
727    else {
728        if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8)) {
729            BIT_skipBits(DStream, dt[val].nbBits);
730            if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
731                /* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
732                DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);
733    }   }
734    return 1;
735}
736
737#define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
738    ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
739
740#define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
741    if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
742        ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
743
744#define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
745    if (MEM_64bits()) \
746        ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
747
748HINT_INLINE size_t
749HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd,
750                const HUF_DEltX2* const dt, const U32 dtLog)
751{
752    BYTE* const pStart = p;
753
754    /* up to 8 symbols at a time */
755    while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-(sizeof(bitDPtr->bitContainer)-1))) {
756        HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
757        HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
758        HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
759        HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
760    }
761
762    /* closer to end : up to 2 symbols at a time */
763    while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd-2))
764        HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
765
766    while (p <= pEnd-2)
767        HUF_DECODE_SYMBOLX2_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
768
769    if (p < pEnd)
770        p += HUF_decodeLastSymbolX2(p, bitDPtr, dt, dtLog);
771
772    return p-pStart;
773}
774
775FORCE_INLINE_TEMPLATE size_t
776HUF_decompress1X2_usingDTable_internal_body(
777          void* dst,  size_t dstSize,
778    const void* cSrc, size_t cSrcSize,
779    const HUF_DTable* DTable)
780{
781    BIT_DStream_t bitD;
782
783    /* Init */
784    CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
785
786    /* decode */
787    {   BYTE* const ostart = (BYTE*) dst;
788        BYTE* const oend = ostart + dstSize;
789        const void* const dtPtr = DTable+1;   /* force compiler to not use strict-aliasing */
790        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
791        DTableDesc const dtd = HUF_getDTableDesc(DTable);
792        HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
793    }
794
795    /* check */
796    if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
797
798    /* decoded size */
799    return dstSize;
800}
801
802FORCE_INLINE_TEMPLATE size_t
803HUF_decompress4X2_usingDTable_internal_body(
804          void* dst,  size_t dstSize,
805    const void* cSrc, size_t cSrcSize,
806    const HUF_DTable* DTable)
807{
808    if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
809
810    {   const BYTE* const istart = (const BYTE*) cSrc;
811        BYTE* const ostart = (BYTE*) dst;
812        BYTE* const oend = ostart + dstSize;
813        BYTE* const olimit = oend - (sizeof(size_t)-1);
814        const void* const dtPtr = DTable+1;
815        const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
816
817        /* Init */
818        BIT_DStream_t bitD1;
819        BIT_DStream_t bitD2;
820        BIT_DStream_t bitD3;
821        BIT_DStream_t bitD4;
822        size_t const length1 = MEM_readLE16(istart);
823        size_t const length2 = MEM_readLE16(istart+2);
824        size_t const length3 = MEM_readLE16(istart+4);
825        size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
826        const BYTE* const istart1 = istart + 6;  /* jumpTable */
827        const BYTE* const istart2 = istart1 + length1;
828        const BYTE* const istart3 = istart2 + length2;
829        const BYTE* const istart4 = istart3 + length3;
830        size_t const segmentSize = (dstSize+3) / 4;
831        BYTE* const opStart2 = ostart + segmentSize;
832        BYTE* const opStart3 = opStart2 + segmentSize;
833        BYTE* const opStart4 = opStart3 + segmentSize;
834        BYTE* op1 = ostart;
835        BYTE* op2 = opStart2;
836        BYTE* op3 = opStart3;
837        BYTE* op4 = opStart4;
838        U32 endSignal = 1;
839        DTableDesc const dtd = HUF_getDTableDesc(DTable);
840        U32 const dtLog = dtd.tableLog;
841
842        if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
843        CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
844        CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
845        CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
846        CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
847
848        /* 16-32 symbols per loop (4-8 symbols per stream) */
849        for ( ; (endSignal) & (op4 < olimit); ) {
850#if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
851            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
852            HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
853            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
854            HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
855            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
856            HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
857            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
858            HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
859            endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
860            endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
861            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
862            HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
863            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
864            HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
865            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
866            HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
867            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
868            HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
869            endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
870            endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
871#else
872            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
873            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
874            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
875            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
876            HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
877            HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
878            HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
879            HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
880            HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
881            HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
882            HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
883            HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
884            HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
885            HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
886            HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
887            HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
888            endSignal = (U32)LIKELY(
889                        (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
890                      & (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
891                      & (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)
892                      & (BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished));
893#endif
894        }
895
896        /* check corruption */
897        if (op1 > opStart2) return ERROR(corruption_detected);
898        if (op2 > opStart3) return ERROR(corruption_detected);
899        if (op3 > opStart4) return ERROR(corruption_detected);
900        /* note : op4 already verified within main loop */
901
902        /* finish bitStreams one by one */
903        HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
904        HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
905        HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
906        HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);
907
908        /* check */
909        { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
910          if (!endCheck) return ERROR(corruption_detected); }
911
912        /* decoded size */
913        return dstSize;
914    }
915}
916
917HUF_DGEN(HUF_decompress1X2_usingDTable_internal)
918HUF_DGEN(HUF_decompress4X2_usingDTable_internal)
919
920size_t HUF_decompress1X2_usingDTable(
921          void* dst,  size_t dstSize,
922    const void* cSrc, size_t cSrcSize,
923    const HUF_DTable* DTable)
924{
925    DTableDesc dtd = HUF_getDTableDesc(DTable);
926    if (dtd.tableType != 1) return ERROR(GENERIC);
927    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
928}
929
930size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
931                                   const void* cSrc, size_t cSrcSize,
932                                   void* workSpace, size_t wkspSize)
933{
934    const BYTE* ip = (const BYTE*) cSrc;
935
936    size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize,
937                                               workSpace, wkspSize);
938    if (HUF_isError(hSize)) return hSize;
939    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
940    ip += hSize; cSrcSize -= hSize;
941
942    return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
943}
944
945
946size_t HUF_decompress4X2_usingDTable(
947          void* dst,  size_t dstSize,
948    const void* cSrc, size_t cSrcSize,
949    const HUF_DTable* DTable)
950{
951    DTableDesc dtd = HUF_getDTableDesc(DTable);
952    if (dtd.tableType != 1) return ERROR(GENERIC);
953    return HUF_decompress4X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
954}
955
956static size_t HUF_decompress4X2_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
957                                   const void* cSrc, size_t cSrcSize,
958                                   void* workSpace, size_t wkspSize, int bmi2)
959{
960    const BYTE* ip = (const BYTE*) cSrc;
961
962    size_t hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize,
963                                         workSpace, wkspSize);
964    if (HUF_isError(hSize)) return hSize;
965    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
966    ip += hSize; cSrcSize -= hSize;
967
968    return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
969}
970
971size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
972                                   const void* cSrc, size_t cSrcSize,
973                                   void* workSpace, size_t wkspSize)
974{
975    return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, /* bmi2 */ 0);
976}
977
978
979#endif /* HUF_FORCE_DECOMPRESS_X1 */
980
981
982/* ***********************************/
983/* Universal decompression selectors */
984/* ***********************************/
985
986size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize,
987                                    const void* cSrc, size_t cSrcSize,
988                                    const HUF_DTable* DTable)
989{
990    DTableDesc const dtd = HUF_getDTableDesc(DTable);
991#if defined(HUF_FORCE_DECOMPRESS_X1)
992    (void)dtd;
993    assert(dtd.tableType == 0);
994    return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
995#elif defined(HUF_FORCE_DECOMPRESS_X2)
996    (void)dtd;
997    assert(dtd.tableType == 1);
998    return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
999#else
1000    return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
1001                           HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1002#endif
1003}
1004
1005size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize,
1006                                    const void* cSrc, size_t cSrcSize,
1007                                    const HUF_DTable* DTable)
1008{
1009    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1010#if defined(HUF_FORCE_DECOMPRESS_X1)
1011    (void)dtd;
1012    assert(dtd.tableType == 0);
1013    return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1014#elif defined(HUF_FORCE_DECOMPRESS_X2)
1015    (void)dtd;
1016    assert(dtd.tableType == 1);
1017    return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1018#else
1019    return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
1020                           HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1021#endif
1022}
1023
1024
1025#if !defined(HUF_FORCE_DECOMPRESS_X1) && !defined(HUF_FORCE_DECOMPRESS_X2)
1026typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
1027static const algo_time_t algoTime[16 /* Quantization */][3 /* single, double, quad */] =
1028{
1029    /* single, double, quad */
1030    {{0,0}, {1,1}, {2,2}},  /* Q==0 : impossible */
1031    {{0,0}, {1,1}, {2,2}},  /* Q==1 : impossible */
1032    {{  38,130}, {1313, 74}, {2151, 38}},   /* Q == 2 : 12-18% */
1033    {{ 448,128}, {1353, 74}, {2238, 41}},   /* Q == 3 : 18-25% */
1034    {{ 556,128}, {1353, 74}, {2238, 47}},   /* Q == 4 : 25-32% */
1035    {{ 714,128}, {1418, 74}, {2436, 53}},   /* Q == 5 : 32-38% */
1036    {{ 883,128}, {1437, 74}, {2464, 61}},   /* Q == 6 : 38-44% */
1037    {{ 897,128}, {1515, 75}, {2622, 68}},   /* Q == 7 : 44-50% */
1038    {{ 926,128}, {1613, 75}, {2730, 75}},   /* Q == 8 : 50-56% */
1039    {{ 947,128}, {1729, 77}, {3359, 77}},   /* Q == 9 : 56-62% */
1040    {{1107,128}, {2083, 81}, {4006, 84}},   /* Q ==10 : 62-69% */
1041    {{1177,128}, {2379, 87}, {4785, 88}},   /* Q ==11 : 69-75% */
1042    {{1242,128}, {2415, 93}, {5155, 84}},   /* Q ==12 : 75-81% */
1043    {{1349,128}, {2644,106}, {5260,106}},   /* Q ==13 : 81-87% */
1044    {{1455,128}, {2422,124}, {4174,124}},   /* Q ==14 : 87-93% */
1045    {{ 722,128}, {1891,145}, {1936,146}},   /* Q ==15 : 93-99% */
1046};
1047#endif
1048
1049/** HUF_selectDecoder() :
1050 *  Tells which decoder is likely to decode faster,
1051 *  based on a set of pre-computed metrics.
1052 * @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
1053 *  Assumption : 0 < dstSize <= 128 KB */
1054U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize)
1055{
1056    assert(dstSize > 0);
1057    assert(dstSize <= 128*1024);
1058#if defined(HUF_FORCE_DECOMPRESS_X1)
1059    (void)dstSize;
1060    (void)cSrcSize;
1061    return 0;
1062#elif defined(HUF_FORCE_DECOMPRESS_X2)
1063    (void)dstSize;
1064    (void)cSrcSize;
1065    return 1;
1066#else
1067    /* decoder timing evaluation */
1068    {   U32 const Q = (cSrcSize >= dstSize) ? 15 : (U32)(cSrcSize * 16 / dstSize);   /* Q < 16 */
1069        U32 const D256 = (U32)(dstSize >> 8);
1070        U32 const DTime0 = algoTime[Q][0].tableTime + (algoTime[Q][0].decode256Time * D256);
1071        U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * D256);
1072        DTime1 += DTime1 >> 3;  /* advantage to algorithm using less memory, to reduce cache eviction */
1073        return DTime1 < DTime0;
1074    }
1075#endif
1076}
1077
1078
1079size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst,
1080                                     size_t dstSize, const void* cSrc,
1081                                     size_t cSrcSize, void* workSpace,
1082                                     size_t wkspSize)
1083{
1084    /* validation checks */
1085    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1086    if (cSrcSize == 0) return ERROR(corruption_detected);
1087
1088    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1089#if defined(HUF_FORCE_DECOMPRESS_X1)
1090        (void)algoNb;
1091        assert(algoNb == 0);
1092        return HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1093#elif defined(HUF_FORCE_DECOMPRESS_X2)
1094        (void)algoNb;
1095        assert(algoNb == 1);
1096        return HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1097#else
1098        return algoNb ? HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1099                            cSrcSize, workSpace, wkspSize):
1100                        HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1101#endif
1102    }
1103}
1104
1105size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
1106                                  const void* cSrc, size_t cSrcSize,
1107                                  void* workSpace, size_t wkspSize)
1108{
1109    /* validation checks */
1110    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1111    if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
1112    if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
1113    if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
1114
1115    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1116#if defined(HUF_FORCE_DECOMPRESS_X1)
1117        (void)algoNb;
1118        assert(algoNb == 0);
1119        return HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
1120                                cSrcSize, workSpace, wkspSize);
1121#elif defined(HUF_FORCE_DECOMPRESS_X2)
1122        (void)algoNb;
1123        assert(algoNb == 1);
1124        return HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1125                                cSrcSize, workSpace, wkspSize);
1126#else
1127        return algoNb ? HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1128                                cSrcSize, workSpace, wkspSize):
1129                        HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
1130                                cSrcSize, workSpace, wkspSize);
1131#endif
1132    }
1133}
1134
1135
1136size_t HUF_decompress1X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
1137{
1138    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1139#if defined(HUF_FORCE_DECOMPRESS_X1)
1140    (void)dtd;
1141    assert(dtd.tableType == 0);
1142    return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1143#elif defined(HUF_FORCE_DECOMPRESS_X2)
1144    (void)dtd;
1145    assert(dtd.tableType == 1);
1146    return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1147#else
1148    return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
1149                           HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1150#endif
1151}
1152
1153#ifndef HUF_FORCE_DECOMPRESS_X2
1154size_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)
1155{
1156    const BYTE* ip = (const BYTE*) cSrc;
1157
1158    size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1159    if (HUF_isError(hSize)) return hSize;
1160    if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
1161    ip += hSize; cSrcSize -= hSize;
1162
1163    return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
1164}
1165#endif
1166
1167size_t HUF_decompress4X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
1168{
1169    DTableDesc const dtd = HUF_getDTableDesc(DTable);
1170#if defined(HUF_FORCE_DECOMPRESS_X1)
1171    (void)dtd;
1172    assert(dtd.tableType == 0);
1173    return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1174#elif defined(HUF_FORCE_DECOMPRESS_X2)
1175    (void)dtd;
1176    assert(dtd.tableType == 1);
1177    return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1178#else
1179    return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
1180                           HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1181#endif
1182}
1183
1184size_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)
1185{
1186    /* validation checks */
1187    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1188    if (cSrcSize == 0) return ERROR(corruption_detected);
1189
1190    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1191#if defined(HUF_FORCE_DECOMPRESS_X1)
1192        (void)algoNb;
1193        assert(algoNb == 0);
1194        return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1195#elif defined(HUF_FORCE_DECOMPRESS_X2)
1196        (void)algoNb;
1197        assert(algoNb == 1);
1198        return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1199#else
1200        return algoNb ? HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2) :
1201                        HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1202#endif
1203    }
1204}
1205
1206#ifndef ZSTD_NO_UNUSED_FUNCTIONS
1207#ifndef HUF_FORCE_DECOMPRESS_X2
1208size_t HUF_readDTableX1(HUF_DTable* DTable, const void* src, size_t srcSize)
1209{
1210    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1211    return HUF_readDTableX1_wksp(DTable, src, srcSize,
1212                                 workSpace, sizeof(workSpace));
1213}
1214
1215size_t HUF_decompress1X1_DCtx(HUF_DTable* DCtx, void* dst, size_t dstSize,
1216                              const void* cSrc, size_t cSrcSize)
1217{
1218    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1219    return HUF_decompress1X1_DCtx_wksp(DCtx, dst, dstSize, cSrc, cSrcSize,
1220                                       workSpace, sizeof(workSpace));
1221}
1222
1223size_t HUF_decompress1X1 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1224{
1225    HUF_CREATE_STATIC_DTABLEX1(DTable, HUF_TABLELOG_MAX);
1226    return HUF_decompress1X1_DCtx (DTable, dst, dstSize, cSrc, cSrcSize);
1227}
1228#endif
1229
1230#ifndef HUF_FORCE_DECOMPRESS_X1
1231size_t HUF_readDTableX2(HUF_DTable* DTable, const void* src, size_t srcSize)
1232{
1233  U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1234  return HUF_readDTableX2_wksp(DTable, src, srcSize,
1235                               workSpace, sizeof(workSpace));
1236}
1237
1238size_t HUF_decompress1X2_DCtx(HUF_DTable* DCtx, void* dst, size_t dstSize,
1239                              const void* cSrc, size_t cSrcSize)
1240{
1241    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1242    return HUF_decompress1X2_DCtx_wksp(DCtx, dst, dstSize, cSrc, cSrcSize,
1243                                       workSpace, sizeof(workSpace));
1244}
1245
1246size_t HUF_decompress1X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1247{
1248    HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_TABLELOG_MAX);
1249    return HUF_decompress1X2_DCtx(DTable, dst, dstSize, cSrc, cSrcSize);
1250}
1251#endif
1252
1253#ifndef HUF_FORCE_DECOMPRESS_X2
1254size_t HUF_decompress4X1_DCtx (HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1255{
1256    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1257    return HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize,
1258                                       workSpace, sizeof(workSpace));
1259}
1260size_t HUF_decompress4X1 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1261{
1262    HUF_CREATE_STATIC_DTABLEX1(DTable, HUF_TABLELOG_MAX);
1263    return HUF_decompress4X1_DCtx(DTable, dst, dstSize, cSrc, cSrcSize);
1264}
1265#endif
1266
1267#ifndef HUF_FORCE_DECOMPRESS_X1
1268size_t HUF_decompress4X2_DCtx(HUF_DTable* dctx, void* dst, size_t dstSize,
1269                              const void* cSrc, size_t cSrcSize)
1270{
1271    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1272    return HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize,
1273                                       workSpace, sizeof(workSpace));
1274}
1275
1276size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1277{
1278    HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_TABLELOG_MAX);
1279    return HUF_decompress4X2_DCtx(DTable, dst, dstSize, cSrc, cSrcSize);
1280}
1281#endif
1282
1283typedef size_t (*decompressionAlgo)(void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);
1284
1285size_t HUF_decompress (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1286{
1287#if !defined(HUF_FORCE_DECOMPRESS_X1) && !defined(HUF_FORCE_DECOMPRESS_X2)
1288    static const decompressionAlgo decompress[2] = { HUF_decompress4X1, HUF_decompress4X2 };
1289#endif
1290
1291    /* validation checks */
1292    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1293    if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
1294    if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
1295    if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
1296
1297    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1298#if defined(HUF_FORCE_DECOMPRESS_X1)
1299        (void)algoNb;
1300        assert(algoNb == 0);
1301        return HUF_decompress4X1(dst, dstSize, cSrc, cSrcSize);
1302#elif defined(HUF_FORCE_DECOMPRESS_X2)
1303        (void)algoNb;
1304        assert(algoNb == 1);
1305        return HUF_decompress4X2(dst, dstSize, cSrc, cSrcSize);
1306#else
1307        return decompress[algoNb](dst, dstSize, cSrc, cSrcSize);
1308#endif
1309    }
1310}
1311
1312size_t HUF_decompress4X_DCtx (HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1313{
1314    /* validation checks */
1315    if (dstSize == 0) return ERROR(dstSize_tooSmall);
1316    if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
1317    if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
1318    if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
1319
1320    {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1321#if defined(HUF_FORCE_DECOMPRESS_X1)
1322        (void)algoNb;
1323        assert(algoNb == 0);
1324        return HUF_decompress4X1_DCtx(dctx, dst, dstSize, cSrc, cSrcSize);
1325#elif defined(HUF_FORCE_DECOMPRESS_X2)
1326        (void)algoNb;
1327        assert(algoNb == 1);
1328        return HUF_decompress4X2_DCtx(dctx, dst, dstSize, cSrc, cSrcSize);
1329#else
1330        return algoNb ? HUF_decompress4X2_DCtx(dctx, dst, dstSize, cSrc, cSrcSize) :
1331                        HUF_decompress4X1_DCtx(dctx, dst, dstSize, cSrc, cSrcSize) ;
1332#endif
1333    }
1334}
1335
1336size_t HUF_decompress4X_hufOnly(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1337{
1338    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1339    return HUF_decompress4X_hufOnly_wksp(dctx, dst, dstSize, cSrc, cSrcSize,
1340                                         workSpace, sizeof(workSpace));
1341}
1342
1343size_t HUF_decompress1X_DCtx(HUF_DTable* dctx, void* dst, size_t dstSize,
1344                             const void* cSrc, size_t cSrcSize)
1345{
1346    U32 workSpace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
1347    return HUF_decompress1X_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize,
1348                                      workSpace, sizeof(workSpace));
1349}
1350#endif
1351