xref: /freebsd/sys/contrib/zstd/lib/decompress/huf_decompress.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 /*-***************************/
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)
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 
569 static 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 
611 size_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 
712 FORCE_INLINE_TEMPLATE U32
713 HUF_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 
721 FORCE_INLINE_TEMPLATE U32
722 HUF_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 
748 HINT_INLINE size_t
749 HUF_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 
775 FORCE_INLINE_TEMPLATE size_t
776 HUF_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 
802 FORCE_INLINE_TEMPLATE size_t
803 HUF_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 
917 HUF_DGEN(HUF_decompress1X2_usingDTable_internal)
918 HUF_DGEN(HUF_decompress4X2_usingDTable_internal)
919 
920 size_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 
930 size_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 
946 size_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 
956 static 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 
971 size_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 
986 size_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 
1005 size_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)
1026 typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
1027 static 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 */
1054 U32 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 
1079 size_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 
1105 size_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 
1136 size_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
1154 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)
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 
1167 size_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 
1184 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)
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
1208 size_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 
1215 size_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 
1223 size_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
1231 size_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 
1238 size_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 
1246 size_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
1254 size_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 }
1260 size_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
1268 size_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 
1276 size_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 
1283 typedef size_t (*decompressionAlgo)(void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);
1284 
1285 size_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 
1312 size_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 
1336 size_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 
1343 size_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