1 /* ******************************************************************
2  * huff0 huffman decoder,
3  * part of Finite State Entropy library
4  * Copyright (c) Yann Collet, Facebook, Inc.
5  *
6  *  You can contact the author at :
7  *  - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
8  *
9  * This source code is licensed under both the BSD-style license (found in the
10  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
11  * in the COPYING file in the root directory of this source tree).
12  * You may select, at your option, one of the above-listed licenses.
13 ****************************************************************** */
14 
15 /* **************************************************************
16 *  Dependencies
17 ****************************************************************/
18 #include "../common/zstd_deps.h"  /* ZSTD_memcpy, ZSTD_memset */
19 #include "../common/compiler.h"
20 #include "../common/bitstream.h"  /* BIT_* */
21 #include "../common/fse.h"        /* to compress headers */
22 #define HUF_STATIC_LINKING_ONLY
23 #include "../common/huf.h"
24 #include "../common/error_private.h"
25 
26 /* **************************************************************
27 *  Macros
28 ****************************************************************/
29 
30 /* These two optional macros force the use one way or another of the two
31  * Huffman decompression implementations. You can't force in both directions
32  * at the same time.
33  */
34 #if defined(HUF_FORCE_DECOMPRESS_X1) && \
35     defined(HUF_FORCE_DECOMPRESS_X2)
36 #error "Cannot force the use of the X1 and X2 decoders at the same time!"
37 #endif
38 
39 
40 /* **************************************************************
41 *  Error Management
42 ****************************************************************/
43 #define HUF_isError ERR_isError
44 
45 
46 /* **************************************************************
47 *  Byte alignment for workSpace management
48 ****************************************************************/
49 #define HUF_ALIGN(x, a)         HUF_ALIGN_MASK((x), (a) - 1)
50 #define HUF_ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
51 
52 
53 /* **************************************************************
54 *  BMI2 Variant Wrappers
55 ****************************************************************/
56 #if DYNAMIC_BMI2
57 
58 #define HUF_DGEN(fn)                                                        \
59                                                                             \
60     static size_t fn##_default(                                             \
61                   void* dst,  size_t dstSize,                               \
62             const void* cSrc, size_t cSrcSize,                              \
63             const HUF_DTable* DTable)                                       \
64     {                                                                       \
65         return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
66     }                                                                       \
67                                                                             \
68     static TARGET_ATTRIBUTE("bmi2") size_t fn##_bmi2(                       \
69                   void* dst,  size_t dstSize,                               \
70             const void* cSrc, size_t cSrcSize,                              \
71             const HUF_DTable* DTable)                                       \
72     {                                                                       \
73         return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
74     }                                                                       \
75                                                                             \
76     static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
77                      size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
78     {                                                                       \
79         if (bmi2) {                                                         \
80             return fn##_bmi2(dst, dstSize, cSrc, cSrcSize, DTable);         \
81         }                                                                   \
82         return fn##_default(dst, dstSize, cSrc, cSrcSize, DTable);          \
83     }
84 
85 #else
86 
87 #define HUF_DGEN(fn)                                                        \
88     static size_t fn(void* dst, size_t dstSize, void const* cSrc,           \
89                      size_t cSrcSize, HUF_DTable const* DTable, int bmi2)   \
90     {                                                                       \
91         (void)bmi2;                                                         \
92         return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable);             \
93     }
94 
95 #endif
96 
97 
98 /*-***************************/
99 /*  generic DTableDesc       */
100 /*-***************************/
101 typedef struct { BYTE maxTableLog; BYTE tableType; BYTE tableLog; BYTE reserved; } DTableDesc;
102 
103 static 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 /*-***************************/
116 typedef 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  */
122 static 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 
133 typedef 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 
142 size_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 
147 size_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 
281 FORCE_INLINE_TEMPLATE BYTE
282 HUF_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 
301 HINT_INLINE size_t
302 HUF_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 
326 FORCE_INLINE_TEMPLATE size_t
327 HUF_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 
349 FORCE_INLINE_TEMPLATE size_t
350 HUF_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 
444 typedef 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 
449 HUF_DGEN(HUF_decompress1X1_usingDTable_internal)
450 HUF_DGEN(HUF_decompress4X1_usingDTable_internal)
451 
452 
453 
454 size_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 
464 size_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 
479 size_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 
489 static 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 
503 size_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 
520 typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX2;  /* double-symbols decoding */
521 typedef struct { BYTE symbol; BYTE weight; } sortedSymbol_t;
522 typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
523 typedef 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 */
528 static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 sizeLog, const U32 consumed,
529                            const U32* rankValOrigin, const int minWeight,
530                            const sortedSymbol_t* sortedSymbols, const U32 sortedListSize,
531                            U32 nbBitsBaseline, U16 baseSeq, U32* wksp, size_t wkspSize)
532 {
533     HUF_DEltX2 DElt;
534     U32* rankVal = wksp;
535 
536     assert(wkspSize >= HUF_TABLELOG_MAX + 1);
537     (void)wkspSize;
538     /* get pre-calculated rankVal */
539     ZSTD_memcpy(rankVal, rankValOrigin, sizeof(U32) * (HUF_TABLELOG_MAX + 1));
540 
541     /* fill skipped values */
542     if (minWeight>1) {
543         U32 i, skipSize = rankVal[minWeight];
544         MEM_writeLE16(&(DElt.sequence), baseSeq);
545         DElt.nbBits   = (BYTE)(consumed);
546         DElt.length   = 1;
547         for (i = 0; i < skipSize; i++)
548             DTable[i] = DElt;
549     }
550 
551     /* fill DTable */
552     {   U32 s; for (s=0; s<sortedListSize; s++) {   /* note : sortedSymbols already skipped */
553             const U32 symbol = sortedSymbols[s].symbol;
554             const U32 weight = sortedSymbols[s].weight;
555             const U32 nbBits = nbBitsBaseline - weight;
556             const U32 length = 1 << (sizeLog-nbBits);
557             const U32 start = rankVal[weight];
558             U32 i = start;
559             const U32 end = start + length;
560 
561             MEM_writeLE16(&(DElt.sequence), (U16)(baseSeq + (symbol << 8)));
562             DElt.nbBits = (BYTE)(nbBits + consumed);
563             DElt.length = 2;
564             do { DTable[i++] = DElt; } while (i<end);   /* since length >= 1 */
565 
566             rankVal[weight] += length;
567     }   }
568 }
569 
570 
571 static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
572                            const sortedSymbol_t* sortedList, const U32 sortedListSize,
573                            const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
574                            const U32 nbBitsBaseline, U32* wksp, size_t wkspSize)
575 {
576     U32* rankVal = wksp;
577     const int scaleLog = nbBitsBaseline - targetLog;   /* note : targetLog >= srcLog, hence scaleLog <= 1 */
578     const U32 minBits  = nbBitsBaseline - maxWeight;
579     U32 s;
580 
581     assert(wkspSize >= HUF_TABLELOG_MAX + 1);
582     wksp += HUF_TABLELOG_MAX + 1;
583     wkspSize -= HUF_TABLELOG_MAX + 1;
584 
585     ZSTD_memcpy(rankVal, rankValOrigin, sizeof(U32) * (HUF_TABLELOG_MAX + 1));
586 
587     /* fill DTable */
588     for (s=0; s<sortedListSize; s++) {
589         const U16 symbol = sortedList[s].symbol;
590         const U32 weight = sortedList[s].weight;
591         const U32 nbBits = nbBitsBaseline - weight;
592         const U32 start = rankVal[weight];
593         const U32 length = 1 << (targetLog-nbBits);
594 
595         if (targetLog-nbBits >= minBits) {   /* enough room for a second symbol */
596             U32 sortedRank;
597             int minWeight = nbBits + scaleLog;
598             if (minWeight < 1) minWeight = 1;
599             sortedRank = rankStart[minWeight];
600             HUF_fillDTableX2Level2(DTable+start, targetLog-nbBits, nbBits,
601                            rankValOrigin[nbBits], minWeight,
602                            sortedList+sortedRank, sortedListSize-sortedRank,
603                            nbBitsBaseline, symbol, wksp, wkspSize);
604         } else {
605             HUF_DEltX2 DElt;
606             MEM_writeLE16(&(DElt.sequence), symbol);
607             DElt.nbBits = (BYTE)(nbBits);
608             DElt.length = 1;
609             {   U32 const end = start + length;
610                 U32 u;
611                 for (u = start; u < end; u++) DTable[u] = DElt;
612         }   }
613         rankVal[weight] += length;
614     }
615 }
616 
617 typedef struct {
618     rankValCol_t rankVal[HUF_TABLELOG_MAX];
619     U32 rankStats[HUF_TABLELOG_MAX + 1];
620     U32 rankStart0[HUF_TABLELOG_MAX + 2];
621     sortedSymbol_t sortedSymbol[HUF_SYMBOLVALUE_MAX + 1];
622     BYTE weightList[HUF_SYMBOLVALUE_MAX + 1];
623     U32 calleeWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
624 } HUF_ReadDTableX2_Workspace;
625 
626 size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
627                        const void* src, size_t srcSize,
628                              void* workSpace, size_t wkspSize)
629 {
630     U32 tableLog, maxW, sizeOfSort, nbSymbols;
631     DTableDesc dtd = HUF_getDTableDesc(DTable);
632     U32 const maxTableLog = dtd.maxTableLog;
633     size_t iSize;
634     void* dtPtr = DTable+1;   /* force compiler to avoid strict-aliasing */
635     HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
636     U32 *rankStart;
637 
638     HUF_ReadDTableX2_Workspace* const wksp = (HUF_ReadDTableX2_Workspace*)workSpace;
639 
640     if (sizeof(*wksp) > wkspSize) return ERROR(GENERIC);
641 
642     rankStart = wksp->rankStart0 + 1;
643     ZSTD_memset(wksp->rankStats, 0, sizeof(wksp->rankStats));
644     ZSTD_memset(wksp->rankStart0, 0, sizeof(wksp->rankStart0));
645 
646     DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(HUF_DTable));   /* if compiler fails here, assertion is wrong */
647     if (maxTableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
648     /* ZSTD_memset(weightList, 0, sizeof(weightList)); */  /* is not necessary, even though some analyzer complain ... */
649 
650     iSize = HUF_readStats_wksp(wksp->weightList, HUF_SYMBOLVALUE_MAX + 1, wksp->rankStats, &nbSymbols, &tableLog, src, srcSize, wksp->calleeWksp, sizeof(wksp->calleeWksp), /* bmi2 */ 0);
651     if (HUF_isError(iSize)) return iSize;
652 
653     /* check result */
654     if (tableLog > maxTableLog) return ERROR(tableLog_tooLarge);   /* DTable can't fit code depth */
655 
656     /* find maxWeight */
657     for (maxW = tableLog; wksp->rankStats[maxW]==0; maxW--) {}  /* necessarily finds a solution before 0 */
658 
659     /* Get start index of each weight */
660     {   U32 w, nextRankStart = 0;
661         for (w=1; w<maxW+1; w++) {
662             U32 curr = nextRankStart;
663             nextRankStart += wksp->rankStats[w];
664             rankStart[w] = curr;
665         }
666         rankStart[0] = nextRankStart;   /* put all 0w symbols at the end of sorted list*/
667         sizeOfSort = nextRankStart;
668     }
669 
670     /* sort symbols by weight */
671     {   U32 s;
672         for (s=0; s<nbSymbols; s++) {
673             U32 const w = wksp->weightList[s];
674             U32 const r = rankStart[w]++;
675             wksp->sortedSymbol[r].symbol = (BYTE)s;
676             wksp->sortedSymbol[r].weight = (BYTE)w;
677         }
678         rankStart[0] = 0;   /* forget 0w symbols; this is beginning of weight(1) */
679     }
680 
681     /* Build rankVal */
682     {   U32* const rankVal0 = wksp->rankVal[0];
683         {   int const rescale = (maxTableLog-tableLog) - 1;   /* tableLog <= maxTableLog */
684             U32 nextRankVal = 0;
685             U32 w;
686             for (w=1; w<maxW+1; w++) {
687                 U32 curr = nextRankVal;
688                 nextRankVal += wksp->rankStats[w] << (w+rescale);
689                 rankVal0[w] = curr;
690         }   }
691         {   U32 const minBits = tableLog+1 - maxW;
692             U32 consumed;
693             for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
694                 U32* const rankValPtr = wksp->rankVal[consumed];
695                 U32 w;
696                 for (w = 1; w < maxW+1; w++) {
697                     rankValPtr[w] = rankVal0[w] >> consumed;
698     }   }   }   }
699 
700     HUF_fillDTableX2(dt, maxTableLog,
701                    wksp->sortedSymbol, sizeOfSort,
702                    wksp->rankStart0, wksp->rankVal, maxW,
703                    tableLog+1,
704                    wksp->calleeWksp, sizeof(wksp->calleeWksp) / sizeof(U32));
705 
706     dtd.tableLog = (BYTE)maxTableLog;
707     dtd.tableType = 1;
708     ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
709     return iSize;
710 }
711 
712 
713 FORCE_INLINE_TEMPLATE U32
714 HUF_decodeSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
715 {
716     size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
717     ZSTD_memcpy(op, dt+val, 2);
718     BIT_skipBits(DStream, dt[val].nbBits);
719     return dt[val].length;
720 }
721 
722 FORCE_INLINE_TEMPLATE U32
723 HUF_decodeLastSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
724 {
725     size_t const val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
726     ZSTD_memcpy(op, dt+val, 1);
727     if (dt[val].length==1) BIT_skipBits(DStream, dt[val].nbBits);
728     else {
729         if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8)) {
730             BIT_skipBits(DStream, dt[val].nbBits);
731             if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
732                 /* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
733                 DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);
734     }   }
735     return 1;
736 }
737 
738 #define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
739     ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
740 
741 #define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
742     if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
743         ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
744 
745 #define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
746     if (MEM_64bits()) \
747         ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog)
748 
749 HINT_INLINE size_t
750 HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd,
751                 const HUF_DEltX2* const dt, const U32 dtLog)
752 {
753     BYTE* const pStart = p;
754 
755     /* up to 8 symbols at a time */
756     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-(sizeof(bitDPtr->bitContainer)-1))) {
757         HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
758         HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
759         HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
760         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
761     }
762 
763     /* closer to end : up to 2 symbols at a time */
764     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd-2))
765         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
766 
767     while (p <= pEnd-2)
768         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
769 
770     if (p < pEnd)
771         p += HUF_decodeLastSymbolX2(p, bitDPtr, dt, dtLog);
772 
773     return p-pStart;
774 }
775 
776 FORCE_INLINE_TEMPLATE size_t
777 HUF_decompress1X2_usingDTable_internal_body(
778           void* dst,  size_t dstSize,
779     const void* cSrc, size_t cSrcSize,
780     const HUF_DTable* DTable)
781 {
782     BIT_DStream_t bitD;
783 
784     /* Init */
785     CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
786 
787     /* decode */
788     {   BYTE* const ostart = (BYTE*) dst;
789         BYTE* const oend = ostart + dstSize;
790         const void* const dtPtr = DTable+1;   /* force compiler to not use strict-aliasing */
791         const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
792         DTableDesc const dtd = HUF_getDTableDesc(DTable);
793         HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
794     }
795 
796     /* check */
797     if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
798 
799     /* decoded size */
800     return dstSize;
801 }
802 
803 FORCE_INLINE_TEMPLATE size_t
804 HUF_decompress4X2_usingDTable_internal_body(
805           void* dst,  size_t dstSize,
806     const void* cSrc, size_t cSrcSize,
807     const HUF_DTable* DTable)
808 {
809     if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
810 
811     {   const BYTE* const istart = (const BYTE*) cSrc;
812         BYTE* const ostart = (BYTE*) dst;
813         BYTE* const oend = ostart + dstSize;
814         BYTE* const olimit = oend - (sizeof(size_t)-1);
815         const void* const dtPtr = DTable+1;
816         const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
817 
818         /* Init */
819         BIT_DStream_t bitD1;
820         BIT_DStream_t bitD2;
821         BIT_DStream_t bitD3;
822         BIT_DStream_t bitD4;
823         size_t const length1 = MEM_readLE16(istart);
824         size_t const length2 = MEM_readLE16(istart+2);
825         size_t const length3 = MEM_readLE16(istart+4);
826         size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
827         const BYTE* const istart1 = istart + 6;  /* jumpTable */
828         const BYTE* const istart2 = istart1 + length1;
829         const BYTE* const istart3 = istart2 + length2;
830         const BYTE* const istart4 = istart3 + length3;
831         size_t const segmentSize = (dstSize+3) / 4;
832         BYTE* const opStart2 = ostart + segmentSize;
833         BYTE* const opStart3 = opStart2 + segmentSize;
834         BYTE* const opStart4 = opStart3 + segmentSize;
835         BYTE* op1 = ostart;
836         BYTE* op2 = opStart2;
837         BYTE* op3 = opStart3;
838         BYTE* op4 = opStart4;
839         U32 endSignal = 1;
840         DTableDesc const dtd = HUF_getDTableDesc(DTable);
841         U32 const dtLog = dtd.tableLog;
842 
843         if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
844         CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
845         CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
846         CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
847         CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
848 
849         /* 16-32 symbols per loop (4-8 symbols per stream) */
850         for ( ; (endSignal) & (op4 < olimit); ) {
851 #if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
852             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
853             HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
854             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
855             HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
856             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
857             HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
858             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
859             HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
860             endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
861             endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
862             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
863             HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
864             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
865             HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
866             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
867             HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
868             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
869             HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
870             endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
871             endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
872 #else
873             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
874             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
875             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
876             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
877             HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
878             HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
879             HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
880             HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
881             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
882             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
883             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
884             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
885             HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
886             HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
887             HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
888             HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
889             endSignal = (U32)LIKELY((U32)
890                         (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
891                       & (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
892                       & (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)
893                       & (BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished));
894 #endif
895         }
896 
897         /* check corruption */
898         if (op1 > opStart2) return ERROR(corruption_detected);
899         if (op2 > opStart3) return ERROR(corruption_detected);
900         if (op3 > opStart4) return ERROR(corruption_detected);
901         /* note : op4 already verified within main loop */
902 
903         /* finish bitStreams one by one */
904         HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
905         HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
906         HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
907         HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);
908 
909         /* check */
910         { U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
911           if (!endCheck) return ERROR(corruption_detected); }
912 
913         /* decoded size */
914         return dstSize;
915     }
916 }
917 
918 HUF_DGEN(HUF_decompress1X2_usingDTable_internal)
919 HUF_DGEN(HUF_decompress4X2_usingDTable_internal)
920 
921 size_t HUF_decompress1X2_usingDTable(
922           void* dst,  size_t dstSize,
923     const void* cSrc, size_t cSrcSize,
924     const HUF_DTable* DTable)
925 {
926     DTableDesc dtd = HUF_getDTableDesc(DTable);
927     if (dtd.tableType != 1) return ERROR(GENERIC);
928     return HUF_decompress1X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
929 }
930 
931 size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
932                                    const void* cSrc, size_t cSrcSize,
933                                    void* workSpace, size_t wkspSize)
934 {
935     const BYTE* ip = (const BYTE*) cSrc;
936 
937     size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize,
938                                                workSpace, wkspSize);
939     if (HUF_isError(hSize)) return hSize;
940     if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
941     ip += hSize; cSrcSize -= hSize;
942 
943     return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, /* bmi2 */ 0);
944 }
945 
946 
947 size_t HUF_decompress4X2_usingDTable(
948           void* dst,  size_t dstSize,
949     const void* cSrc, size_t cSrcSize,
950     const HUF_DTable* DTable)
951 {
952     DTableDesc dtd = HUF_getDTableDesc(DTable);
953     if (dtd.tableType != 1) return ERROR(GENERIC);
954     return HUF_decompress4X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
955 }
956 
957 static size_t HUF_decompress4X2_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize,
958                                    const void* cSrc, size_t cSrcSize,
959                                    void* workSpace, size_t wkspSize, int bmi2)
960 {
961     const BYTE* ip = (const BYTE*) cSrc;
962 
963     size_t hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize,
964                                          workSpace, wkspSize);
965     if (HUF_isError(hSize)) return hSize;
966     if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
967     ip += hSize; cSrcSize -= hSize;
968 
969     return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
970 }
971 
972 size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
973                                    const void* cSrc, size_t cSrcSize,
974                                    void* workSpace, size_t wkspSize)
975 {
976     return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, /* bmi2 */ 0);
977 }
978 
979 
980 #endif /* HUF_FORCE_DECOMPRESS_X1 */
981 
982 
983 /* ***********************************/
984 /* Universal decompression selectors */
985 /* ***********************************/
986 
987 size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize,
988                                     const void* cSrc, size_t cSrcSize,
989                                     const HUF_DTable* DTable)
990 {
991     DTableDesc const dtd = HUF_getDTableDesc(DTable);
992 #if defined(HUF_FORCE_DECOMPRESS_X1)
993     (void)dtd;
994     assert(dtd.tableType == 0);
995     return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
996 #elif defined(HUF_FORCE_DECOMPRESS_X2)
997     (void)dtd;
998     assert(dtd.tableType == 1);
999     return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1000 #else
1001     return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
1002                            HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1003 #endif
1004 }
1005 
1006 size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize,
1007                                     const void* cSrc, size_t cSrcSize,
1008                                     const HUF_DTable* DTable)
1009 {
1010     DTableDesc const dtd = HUF_getDTableDesc(DTable);
1011 #if defined(HUF_FORCE_DECOMPRESS_X1)
1012     (void)dtd;
1013     assert(dtd.tableType == 0);
1014     return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1015 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1016     (void)dtd;
1017     assert(dtd.tableType == 1);
1018     return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1019 #else
1020     return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0) :
1021                            HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, /* bmi2 */ 0);
1022 #endif
1023 }
1024 
1025 
1026 #if !defined(HUF_FORCE_DECOMPRESS_X1) && !defined(HUF_FORCE_DECOMPRESS_X2)
1027 typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
1028 static const algo_time_t algoTime[16 /* Quantization */][3 /* single, double, quad */] =
1029 {
1030     /* single, double, quad */
1031     {{0,0}, {1,1}, {2,2}},  /* Q==0 : impossible */
1032     {{0,0}, {1,1}, {2,2}},  /* Q==1 : impossible */
1033     {{  38,130}, {1313, 74}, {2151, 38}},   /* Q == 2 : 12-18% */
1034     {{ 448,128}, {1353, 74}, {2238, 41}},   /* Q == 3 : 18-25% */
1035     {{ 556,128}, {1353, 74}, {2238, 47}},   /* Q == 4 : 25-32% */
1036     {{ 714,128}, {1418, 74}, {2436, 53}},   /* Q == 5 : 32-38% */
1037     {{ 883,128}, {1437, 74}, {2464, 61}},   /* Q == 6 : 38-44% */
1038     {{ 897,128}, {1515, 75}, {2622, 68}},   /* Q == 7 : 44-50% */
1039     {{ 926,128}, {1613, 75}, {2730, 75}},   /* Q == 8 : 50-56% */
1040     {{ 947,128}, {1729, 77}, {3359, 77}},   /* Q == 9 : 56-62% */
1041     {{1107,128}, {2083, 81}, {4006, 84}},   /* Q ==10 : 62-69% */
1042     {{1177,128}, {2379, 87}, {4785, 88}},   /* Q ==11 : 69-75% */
1043     {{1242,128}, {2415, 93}, {5155, 84}},   /* Q ==12 : 75-81% */
1044     {{1349,128}, {2644,106}, {5260,106}},   /* Q ==13 : 81-87% */
1045     {{1455,128}, {2422,124}, {4174,124}},   /* Q ==14 : 87-93% */
1046     {{ 722,128}, {1891,145}, {1936,146}},   /* Q ==15 : 93-99% */
1047 };
1048 #endif
1049 
1050 /* HUF_selectDecoder() :
1051  *  Tells which decoder is likely to decode faster,
1052  *  based on a set of pre-computed metrics.
1053  * @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
1054  *  Assumption : 0 < dstSize <= 128 KB */
1055 U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize)
1056 {
1057     assert(dstSize > 0);
1058     assert(dstSize <= 128*1024);
1059 #if defined(HUF_FORCE_DECOMPRESS_X1)
1060     (void)dstSize;
1061     (void)cSrcSize;
1062     return 0;
1063 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1064     (void)dstSize;
1065     (void)cSrcSize;
1066     return 1;
1067 #else
1068     /* decoder timing evaluation */
1069     {   U32 const Q = (cSrcSize >= dstSize) ? 15 : (U32)(cSrcSize * 16 / dstSize);   /* Q < 16 */
1070         U32 const D256 = (U32)(dstSize >> 8);
1071         U32 const DTime0 = algoTime[Q][0].tableTime + (algoTime[Q][0].decode256Time * D256);
1072         U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * D256);
1073         DTime1 += DTime1 >> 3;  /* advantage to algorithm using less memory, to reduce cache eviction */
1074         return DTime1 < DTime0;
1075     }
1076 #endif
1077 }
1078 
1079 
1080 size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst,
1081                                      size_t dstSize, const void* cSrc,
1082                                      size_t cSrcSize, void* workSpace,
1083                                      size_t wkspSize)
1084 {
1085     /* validation checks */
1086     if (dstSize == 0) return ERROR(dstSize_tooSmall);
1087     if (cSrcSize == 0) return ERROR(corruption_detected);
1088 
1089     {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1090 #if defined(HUF_FORCE_DECOMPRESS_X1)
1091         (void)algoNb;
1092         assert(algoNb == 0);
1093         return HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1094 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1095         (void)algoNb;
1096         assert(algoNb == 1);
1097         return HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1098 #else
1099         return algoNb ? HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1100                             cSrcSize, workSpace, wkspSize):
1101                         HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize);
1102 #endif
1103     }
1104 }
1105 
1106 size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
1107                                   const void* cSrc, size_t cSrcSize,
1108                                   void* workSpace, size_t wkspSize)
1109 {
1110     /* validation checks */
1111     if (dstSize == 0) return ERROR(dstSize_tooSmall);
1112     if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
1113     if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
1114     if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
1115 
1116     {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1117 #if defined(HUF_FORCE_DECOMPRESS_X1)
1118         (void)algoNb;
1119         assert(algoNb == 0);
1120         return HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
1121                                 cSrcSize, workSpace, wkspSize);
1122 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1123         (void)algoNb;
1124         assert(algoNb == 1);
1125         return HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1126                                 cSrcSize, workSpace, wkspSize);
1127 #else
1128         return algoNb ? HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
1129                                 cSrcSize, workSpace, wkspSize):
1130                         HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
1131                                 cSrcSize, workSpace, wkspSize);
1132 #endif
1133     }
1134 }
1135 
1136 
1137 size_t HUF_decompress1X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
1138 {
1139     DTableDesc const dtd = HUF_getDTableDesc(DTable);
1140 #if defined(HUF_FORCE_DECOMPRESS_X1)
1141     (void)dtd;
1142     assert(dtd.tableType == 0);
1143     return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1144 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1145     (void)dtd;
1146     assert(dtd.tableType == 1);
1147     return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1148 #else
1149     return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
1150                            HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1151 #endif
1152 }
1153 
1154 #ifndef HUF_FORCE_DECOMPRESS_X2
1155 size_t HUF_decompress1X1_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int bmi2)
1156 {
1157     const BYTE* ip = (const BYTE*) cSrc;
1158 
1159     size_t const hSize = HUF_readDTableX1_wksp_bmi2(dctx, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1160     if (HUF_isError(hSize)) return hSize;
1161     if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
1162     ip += hSize; cSrcSize -= hSize;
1163 
1164     return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, bmi2);
1165 }
1166 #endif
1167 
1168 size_t HUF_decompress4X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2)
1169 {
1170     DTableDesc const dtd = HUF_getDTableDesc(DTable);
1171 #if defined(HUF_FORCE_DECOMPRESS_X1)
1172     (void)dtd;
1173     assert(dtd.tableType == 0);
1174     return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1175 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1176     (void)dtd;
1177     assert(dtd.tableType == 1);
1178     return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1179 #else
1180     return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2) :
1181                            HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, bmi2);
1182 #endif
1183 }
1184 
1185 size_t HUF_decompress4X_hufOnly_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int bmi2)
1186 {
1187     /* validation checks */
1188     if (dstSize == 0) return ERROR(dstSize_tooSmall);
1189     if (cSrcSize == 0) return ERROR(corruption_detected);
1190 
1191     {   U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
1192 #if defined(HUF_FORCE_DECOMPRESS_X1)
1193         (void)algoNb;
1194         assert(algoNb == 0);
1195         return HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1196 #elif defined(HUF_FORCE_DECOMPRESS_X2)
1197         (void)algoNb;
1198         assert(algoNb == 1);
1199         return HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1200 #else
1201         return algoNb ? HUF_decompress4X2_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2) :
1202                         HUF_decompress4X1_DCtx_wksp_bmi2(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, bmi2);
1203 #endif
1204     }
1205 }
1206 
1207