1 /*
2  * Huffman decoder, part of New Generation Entropy library
3  * Copyright (C) 2013-2016, Yann Collet.
4  *
5  * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions are
9  * met:
10  *
11  *   * Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *   * Redistributions in binary form must reproduce the above
14  * copyright notice, this list of conditions and the following disclaimer
15  * in the documentation and/or other materials provided with the
16  * distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  *
30  * This program is free software; you can redistribute it and/or modify it under
31  * the terms of the GNU General Public License version 2 as published by the
32  * Free Software Foundation. This program is dual-licensed; you may select
33  * either version 2 of the GNU General Public License ("GPL") or BSD license
34  * ("BSD").
35  *
36  * You can contact the author at :
37  * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
38  */
39 
40 /* **************************************************************
41 *  Compiler specifics
42 ****************************************************************/
43 #define FORCE_INLINE static __always_inline
44 
45 /* **************************************************************
46 *  Dependencies
47 ****************************************************************/
48 #include "bitstream.h" /* BIT_* */
49 #include "fse.h"       /* header compression */
50 #include "huf.h"
51 #include <linux/compiler.h>
52 #include <linux/kernel.h>
53 #include <linux/string.h> /* memcpy, memset */
54 
55 /* **************************************************************
56 *  Error Management
57 ****************************************************************/
58 #define HUF_STATIC_ASSERT(c)                                   \
59 	{                                                      \
60 		enum { HUF_static_assert = 1 / (int)(!!(c)) }; \
61 	} /* use only *after* variable declarations */
62 
63 /*-***************************/
64 /*  generic DTableDesc       */
65 /*-***************************/
66 
67 typedef struct {
68 	BYTE maxTableLog;
69 	BYTE tableType;
70 	BYTE tableLog;
71 	BYTE reserved;
72 } DTableDesc;
73 
HUF_getDTableDesc(const HUF_DTable * table)74 static DTableDesc HUF_getDTableDesc(const HUF_DTable *table)
75 {
76 	DTableDesc dtd;
77 	memcpy(&dtd, table, sizeof(dtd));
78 	return dtd;
79 }
80 
81 /*-***************************/
82 /*  single-symbol decoding   */
83 /*-***************************/
84 
85 typedef struct {
86 	BYTE byte;
87 	BYTE nbBits;
88 } HUF_DEltX2; /* single-symbol decoding */
89 
HUF_readDTableX2_wksp(HUF_DTable * DTable,const void * src,size_t srcSize,void * workspace,size_t workspaceSize)90 size_t HUF_readDTableX2_wksp(HUF_DTable *DTable, const void *src, size_t srcSize, void *workspace, size_t workspaceSize)
91 {
92 	U32 tableLog = 0;
93 	U32 nbSymbols = 0;
94 	size_t iSize;
95 	void *const dtPtr = DTable + 1;
96 	HUF_DEltX2 *const dt = (HUF_DEltX2 *)dtPtr;
97 
98 	U32 *rankVal;
99 	BYTE *huffWeight;
100 	size_t spaceUsed32 = 0;
101 
102 	rankVal = (U32 *)workspace + spaceUsed32;
103 	spaceUsed32 += HUF_TABLELOG_ABSOLUTEMAX + 1;
104 	huffWeight = (BYTE *)((U32 *)workspace + spaceUsed32);
105 	spaceUsed32 += ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2;
106 
107 	if ((spaceUsed32 << 2) > workspaceSize)
108 		return ERROR(tableLog_tooLarge);
109 	workspace = (U32 *)workspace + spaceUsed32;
110 	workspaceSize -= (spaceUsed32 << 2);
111 
112 	HUF_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUF_DTable));
113 	/* memset(huffWeight, 0, sizeof(huffWeight)); */ /* is not necessary, even though some analyzer complain ... */
114 
115 	iSize = HUF_readStats_wksp(huffWeight, HUF_SYMBOLVALUE_MAX + 1, rankVal, &nbSymbols, &tableLog, src, srcSize, workspace, workspaceSize);
116 	if (HUF_isError(iSize))
117 		return iSize;
118 
119 	/* Table header */
120 	{
121 		DTableDesc dtd = HUF_getDTableDesc(DTable);
122 		if (tableLog > (U32)(dtd.maxTableLog + 1))
123 			return ERROR(tableLog_tooLarge); /* DTable too small, Huffman tree cannot fit in */
124 		dtd.tableType = 0;
125 		dtd.tableLog = (BYTE)tableLog;
126 		memcpy(DTable, &dtd, sizeof(dtd));
127 	}
128 
129 	/* Calculate starting value for each rank */
130 	{
131 		U32 n, nextRankStart = 0;
132 		for (n = 1; n < tableLog + 1; n++) {
133 			U32 const curr = nextRankStart;
134 			nextRankStart += (rankVal[n] << (n - 1));
135 			rankVal[n] = curr;
136 		}
137 	}
138 
139 	/* fill DTable */
140 	{
141 		U32 n;
142 		for (n = 0; n < nbSymbols; n++) {
143 			U32 const w = huffWeight[n];
144 			U32 const length = (1 << w) >> 1;
145 			U32 u;
146 			HUF_DEltX2 D;
147 			D.byte = (BYTE)n;
148 			D.nbBits = (BYTE)(tableLog + 1 - w);
149 			for (u = rankVal[w]; u < rankVal[w] + length; u++)
150 				dt[u] = D;
151 			rankVal[w] += length;
152 		}
153 	}
154 
155 	return iSize;
156 }
157 
HUF_decodeSymbolX2(BIT_DStream_t * Dstream,const HUF_DEltX2 * dt,const U32 dtLog)158 static BYTE HUF_decodeSymbolX2(BIT_DStream_t *Dstream, const HUF_DEltX2 *dt, const U32 dtLog)
159 {
160 	size_t const val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
161 	BYTE const c = dt[val].byte;
162 	BIT_skipBits(Dstream, dt[val].nbBits);
163 	return c;
164 }
165 
166 #define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) *ptr++ = HUF_decodeSymbolX2(DStreamPtr, dt, dtLog)
167 
168 #define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr)         \
169 	if (ZSTD_64bits() || (HUF_TABLELOG_MAX <= 12)) \
170 	HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
171 
172 #define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
173 	if (ZSTD_64bits())                     \
174 	HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
175 
HUF_decodeStreamX2(BYTE * p,BIT_DStream_t * const bitDPtr,BYTE * const pEnd,const HUF_DEltX2 * const dt,const U32 dtLog)176 FORCE_INLINE size_t HUF_decodeStreamX2(BYTE *p, BIT_DStream_t *const bitDPtr, BYTE *const pEnd, const HUF_DEltX2 *const dt, const U32 dtLog)
177 {
178 	BYTE *const pStart = p;
179 
180 	/* up to 4 symbols at a time */
181 	while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p <= pEnd - 4)) {
182 		HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
183 		HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
184 		HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
185 		HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
186 	}
187 
188 	/* closer to the end */
189 	while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p < pEnd))
190 		HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
191 
192 	/* no more data to retrieve from bitstream, hence no need to reload */
193 	while (p < pEnd)
194 		HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
195 
196 	return pEnd - pStart;
197 }
198 
HUF_decompress1X2_usingDTable_internal(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)199 static size_t HUF_decompress1X2_usingDTable_internal(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
200 {
201 	BYTE *op = (BYTE *)dst;
202 	BYTE *const oend = op + dstSize;
203 	const void *dtPtr = DTable + 1;
204 	const HUF_DEltX2 *const dt = (const HUF_DEltX2 *)dtPtr;
205 	BIT_DStream_t bitD;
206 	DTableDesc const dtd = HUF_getDTableDesc(DTable);
207 	U32 const dtLog = dtd.tableLog;
208 
209 	{
210 		size_t const errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);
211 		if (HUF_isError(errorCode))
212 			return errorCode;
213 	}
214 
215 	HUF_decodeStreamX2(op, &bitD, oend, dt, dtLog);
216 
217 	/* check */
218 	if (!BIT_endOfDStream(&bitD))
219 		return ERROR(corruption_detected);
220 
221 	return dstSize;
222 }
223 
HUF_decompress1X2_usingDTable(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)224 size_t HUF_decompress1X2_usingDTable(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
225 {
226 	DTableDesc dtd = HUF_getDTableDesc(DTable);
227 	if (dtd.tableType != 0)
228 		return ERROR(GENERIC);
229 	return HUF_decompress1X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable);
230 }
231 
HUF_decompress1X2_DCtx_wksp(HUF_DTable * DCtx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)232 size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable *DCtx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
233 {
234 	const BYTE *ip = (const BYTE *)cSrc;
235 
236 	size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize, workspace, workspaceSize);
237 	if (HUF_isError(hSize))
238 		return hSize;
239 	if (hSize >= cSrcSize)
240 		return ERROR(srcSize_wrong);
241 	ip += hSize;
242 	cSrcSize -= hSize;
243 
244 	return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx);
245 }
246 
HUF_decompress4X2_usingDTable_internal(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)247 static size_t HUF_decompress4X2_usingDTable_internal(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
248 {
249 	/* Check */
250 	if (cSrcSize < 10)
251 		return ERROR(corruption_detected); /* strict minimum : jump table + 1 byte per stream */
252 
253 	{
254 		const BYTE *const istart = (const BYTE *)cSrc;
255 		BYTE *const ostart = (BYTE *)dst;
256 		BYTE *const oend = ostart + dstSize;
257 		const void *const dtPtr = DTable + 1;
258 		const HUF_DEltX2 *const dt = (const HUF_DEltX2 *)dtPtr;
259 
260 		/* Init */
261 		BIT_DStream_t bitD1;
262 		BIT_DStream_t bitD2;
263 		BIT_DStream_t bitD3;
264 		BIT_DStream_t bitD4;
265 		size_t const length1 = ZSTD_readLE16(istart);
266 		size_t const length2 = ZSTD_readLE16(istart + 2);
267 		size_t const length3 = ZSTD_readLE16(istart + 4);
268 		size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
269 		const BYTE *const istart1 = istart + 6; /* jumpTable */
270 		const BYTE *const istart2 = istart1 + length1;
271 		const BYTE *const istart3 = istart2 + length2;
272 		const BYTE *const istart4 = istart3 + length3;
273 		const size_t segmentSize = (dstSize + 3) / 4;
274 		BYTE *const opStart2 = ostart + segmentSize;
275 		BYTE *const opStart3 = opStart2 + segmentSize;
276 		BYTE *const opStart4 = opStart3 + segmentSize;
277 		BYTE *op1 = ostart;
278 		BYTE *op2 = opStart2;
279 		BYTE *op3 = opStart3;
280 		BYTE *op4 = opStart4;
281 		U32 endSignal;
282 		DTableDesc const dtd = HUF_getDTableDesc(DTable);
283 		U32 const dtLog = dtd.tableLog;
284 
285 		if (length4 > cSrcSize)
286 			return ERROR(corruption_detected); /* overflow */
287 		{
288 			size_t const errorCode = BIT_initDStream(&bitD1, istart1, length1);
289 			if (HUF_isError(errorCode))
290 				return errorCode;
291 		}
292 		{
293 			size_t const errorCode = BIT_initDStream(&bitD2, istart2, length2);
294 			if (HUF_isError(errorCode))
295 				return errorCode;
296 		}
297 		{
298 			size_t const errorCode = BIT_initDStream(&bitD3, istart3, length3);
299 			if (HUF_isError(errorCode))
300 				return errorCode;
301 		}
302 		{
303 			size_t const errorCode = BIT_initDStream(&bitD4, istart4, length4);
304 			if (HUF_isError(errorCode))
305 				return errorCode;
306 		}
307 
308 		/* 16-32 symbols per loop (4-8 symbols per stream) */
309 		endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
310 		for (; (endSignal == BIT_DStream_unfinished) && (op4 < (oend - 7));) {
311 			HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
312 			HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
313 			HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
314 			HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
315 			HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
316 			HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
317 			HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
318 			HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
319 			HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
320 			HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
321 			HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
322 			HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
323 			HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
324 			HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
325 			HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
326 			HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
327 			endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
328 		}
329 
330 		/* check corruption */
331 		if (op1 > opStart2)
332 			return ERROR(corruption_detected);
333 		if (op2 > opStart3)
334 			return ERROR(corruption_detected);
335 		if (op3 > opStart4)
336 			return ERROR(corruption_detected);
337 		/* note : op4 supposed already verified within main loop */
338 
339 		/* finish bitStreams one by one */
340 		HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
341 		HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
342 		HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
343 		HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
344 
345 		/* check */
346 		endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
347 		if (!endSignal)
348 			return ERROR(corruption_detected);
349 
350 		/* decoded size */
351 		return dstSize;
352 	}
353 }
354 
HUF_decompress4X2_usingDTable(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)355 size_t HUF_decompress4X2_usingDTable(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
356 {
357 	DTableDesc dtd = HUF_getDTableDesc(DTable);
358 	if (dtd.tableType != 0)
359 		return ERROR(GENERIC);
360 	return HUF_decompress4X2_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable);
361 }
362 
HUF_decompress4X2_DCtx_wksp(HUF_DTable * dctx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)363 size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
364 {
365 	const BYTE *ip = (const BYTE *)cSrc;
366 
367 	size_t const hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize, workspace, workspaceSize);
368 	if (HUF_isError(hSize))
369 		return hSize;
370 	if (hSize >= cSrcSize)
371 		return ERROR(srcSize_wrong);
372 	ip += hSize;
373 	cSrcSize -= hSize;
374 
375 	return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx);
376 }
377 
378 /* *************************/
379 /* double-symbols decoding */
380 /* *************************/
381 typedef struct {
382 	U16 sequence;
383 	BYTE nbBits;
384 	BYTE length;
385 } HUF_DEltX4; /* double-symbols decoding */
386 
387 typedef struct {
388 	BYTE symbol;
389 	BYTE weight;
390 } sortedSymbol_t;
391 
392 /* HUF_fillDTableX4Level2() :
393  * `rankValOrigin` must be a table of at least (HUF_TABLELOG_MAX + 1) U32 */
HUF_fillDTableX4Level2(HUF_DEltX4 * DTable,U32 sizeLog,const U32 consumed,const U32 * rankValOrigin,const int minWeight,const sortedSymbol_t * sortedSymbols,const U32 sortedListSize,U32 nbBitsBaseline,U16 baseSeq)394 static void HUF_fillDTableX4Level2(HUF_DEltX4 *DTable, U32 sizeLog, const U32 consumed, const U32 *rankValOrigin, const int minWeight,
395 				   const sortedSymbol_t *sortedSymbols, const U32 sortedListSize, U32 nbBitsBaseline, U16 baseSeq)
396 {
397 	HUF_DEltX4 DElt;
398 	U32 rankVal[HUF_TABLELOG_MAX + 1];
399 
400 	/* get pre-calculated rankVal */
401 	memcpy(rankVal, rankValOrigin, sizeof(rankVal));
402 
403 	/* fill skipped values */
404 	if (minWeight > 1) {
405 		U32 i, skipSize = rankVal[minWeight];
406 		ZSTD_writeLE16(&(DElt.sequence), baseSeq);
407 		DElt.nbBits = (BYTE)(consumed);
408 		DElt.length = 1;
409 		for (i = 0; i < skipSize; i++)
410 			DTable[i] = DElt;
411 	}
412 
413 	/* fill DTable */
414 	{
415 		U32 s;
416 		for (s = 0; s < sortedListSize; s++) { /* note : sortedSymbols already skipped */
417 			const U32 symbol = sortedSymbols[s].symbol;
418 			const U32 weight = sortedSymbols[s].weight;
419 			const U32 nbBits = nbBitsBaseline - weight;
420 			const U32 length = 1 << (sizeLog - nbBits);
421 			const U32 start = rankVal[weight];
422 			U32 i = start;
423 			const U32 end = start + length;
424 
425 			ZSTD_writeLE16(&(DElt.sequence), (U16)(baseSeq + (symbol << 8)));
426 			DElt.nbBits = (BYTE)(nbBits + consumed);
427 			DElt.length = 2;
428 			do {
429 				DTable[i++] = DElt;
430 			} while (i < end); /* since length >= 1 */
431 
432 			rankVal[weight] += length;
433 		}
434 	}
435 }
436 
437 typedef U32 rankVal_t[HUF_TABLELOG_MAX][HUF_TABLELOG_MAX + 1];
438 typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
439 
HUF_fillDTableX4(HUF_DEltX4 * DTable,const U32 targetLog,const sortedSymbol_t * sortedList,const U32 sortedListSize,const U32 * rankStart,rankVal_t rankValOrigin,const U32 maxWeight,const U32 nbBitsBaseline)440 static void HUF_fillDTableX4(HUF_DEltX4 *DTable, const U32 targetLog, const sortedSymbol_t *sortedList, const U32 sortedListSize, const U32 *rankStart,
441 			     rankVal_t rankValOrigin, const U32 maxWeight, const U32 nbBitsBaseline)
442 {
443 	U32 rankVal[HUF_TABLELOG_MAX + 1];
444 	const int scaleLog = nbBitsBaseline - targetLog; /* note : targetLog >= srcLog, hence scaleLog <= 1 */
445 	const U32 minBits = nbBitsBaseline - maxWeight;
446 	U32 s;
447 
448 	memcpy(rankVal, rankValOrigin, sizeof(rankVal));
449 
450 	/* fill DTable */
451 	for (s = 0; s < sortedListSize; s++) {
452 		const U16 symbol = sortedList[s].symbol;
453 		const U32 weight = sortedList[s].weight;
454 		const U32 nbBits = nbBitsBaseline - weight;
455 		const U32 start = rankVal[weight];
456 		const U32 length = 1 << (targetLog - nbBits);
457 
458 		if (targetLog - nbBits >= minBits) { /* enough room for a second symbol */
459 			U32 sortedRank;
460 			int minWeight = nbBits + scaleLog;
461 			if (minWeight < 1)
462 				minWeight = 1;
463 			sortedRank = rankStart[minWeight];
464 			HUF_fillDTableX4Level2(DTable + start, targetLog - nbBits, nbBits, rankValOrigin[nbBits], minWeight, sortedList + sortedRank,
465 					       sortedListSize - sortedRank, nbBitsBaseline, symbol);
466 		} else {
467 			HUF_DEltX4 DElt;
468 			ZSTD_writeLE16(&(DElt.sequence), symbol);
469 			DElt.nbBits = (BYTE)(nbBits);
470 			DElt.length = 1;
471 			{
472 				U32 const end = start + length;
473 				U32 u;
474 				for (u = start; u < end; u++)
475 					DTable[u] = DElt;
476 			}
477 		}
478 		rankVal[weight] += length;
479 	}
480 }
481 
HUF_readDTableX4_wksp(HUF_DTable * DTable,const void * src,size_t srcSize,void * workspace,size_t workspaceSize)482 size_t HUF_readDTableX4_wksp(HUF_DTable *DTable, const void *src, size_t srcSize, void *workspace, size_t workspaceSize)
483 {
484 	U32 tableLog, maxW, sizeOfSort, nbSymbols;
485 	DTableDesc dtd = HUF_getDTableDesc(DTable);
486 	U32 const maxTableLog = dtd.maxTableLog;
487 	size_t iSize;
488 	void *dtPtr = DTable + 1; /* force compiler to avoid strict-aliasing */
489 	HUF_DEltX4 *const dt = (HUF_DEltX4 *)dtPtr;
490 	U32 *rankStart;
491 
492 	rankValCol_t *rankVal;
493 	U32 *rankStats;
494 	U32 *rankStart0;
495 	sortedSymbol_t *sortedSymbol;
496 	BYTE *weightList;
497 	size_t spaceUsed32 = 0;
498 
499 	HUF_STATIC_ASSERT((sizeof(rankValCol_t) & 3) == 0);
500 
501 	rankVal = (rankValCol_t *)((U32 *)workspace + spaceUsed32);
502 	spaceUsed32 += (sizeof(rankValCol_t) * HUF_TABLELOG_MAX) >> 2;
503 	rankStats = (U32 *)workspace + spaceUsed32;
504 	spaceUsed32 += HUF_TABLELOG_MAX + 1;
505 	rankStart0 = (U32 *)workspace + spaceUsed32;
506 	spaceUsed32 += HUF_TABLELOG_MAX + 2;
507 	sortedSymbol = (sortedSymbol_t *)((U32 *)workspace + spaceUsed32);
508 	spaceUsed32 += ALIGN(sizeof(sortedSymbol_t) * (HUF_SYMBOLVALUE_MAX + 1), sizeof(U32)) >> 2;
509 	weightList = (BYTE *)((U32 *)workspace + spaceUsed32);
510 	spaceUsed32 += ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2;
511 
512 	if ((spaceUsed32 << 2) > workspaceSize)
513 		return ERROR(tableLog_tooLarge);
514 	workspace = (U32 *)workspace + spaceUsed32;
515 	workspaceSize -= (spaceUsed32 << 2);
516 
517 	rankStart = rankStart0 + 1;
518 	memset(rankStats, 0, sizeof(U32) * (2 * HUF_TABLELOG_MAX + 2 + 1));
519 
520 	HUF_STATIC_ASSERT(sizeof(HUF_DEltX4) == sizeof(HUF_DTable)); /* if compiler fails here, assertion is wrong */
521 	if (maxTableLog > HUF_TABLELOG_MAX)
522 		return ERROR(tableLog_tooLarge);
523 	/* memset(weightList, 0, sizeof(weightList)); */ /* is not necessary, even though some analyzer complain ... */
524 
525 	iSize = HUF_readStats_wksp(weightList, HUF_SYMBOLVALUE_MAX + 1, rankStats, &nbSymbols, &tableLog, src, srcSize, workspace, workspaceSize);
526 	if (HUF_isError(iSize))
527 		return iSize;
528 
529 	/* check result */
530 	if (tableLog > maxTableLog)
531 		return ERROR(tableLog_tooLarge); /* DTable can't fit code depth */
532 
533 	/* find maxWeight */
534 	for (maxW = tableLog; rankStats[maxW] == 0; maxW--) {
535 	} /* necessarily finds a solution before 0 */
536 
537 	/* Get start index of each weight */
538 	{
539 		U32 w, nextRankStart = 0;
540 		for (w = 1; w < maxW + 1; w++) {
541 			U32 curr = nextRankStart;
542 			nextRankStart += rankStats[w];
543 			rankStart[w] = curr;
544 		}
545 		rankStart[0] = nextRankStart; /* put all 0w symbols at the end of sorted list*/
546 		sizeOfSort = nextRankStart;
547 	}
548 
549 	/* sort symbols by weight */
550 	{
551 		U32 s;
552 		for (s = 0; s < nbSymbols; s++) {
553 			U32 const w = weightList[s];
554 			U32 const r = rankStart[w]++;
555 			sortedSymbol[r].symbol = (BYTE)s;
556 			sortedSymbol[r].weight = (BYTE)w;
557 		}
558 		rankStart[0] = 0; /* forget 0w symbols; this is beginning of weight(1) */
559 	}
560 
561 	/* Build rankVal */
562 	{
563 		U32 *const rankVal0 = rankVal[0];
564 		{
565 			int const rescale = (maxTableLog - tableLog) - 1; /* tableLog <= maxTableLog */
566 			U32 nextRankVal = 0;
567 			U32 w;
568 			for (w = 1; w < maxW + 1; w++) {
569 				U32 curr = nextRankVal;
570 				nextRankVal += rankStats[w] << (w + rescale);
571 				rankVal0[w] = curr;
572 			}
573 		}
574 		{
575 			U32 const minBits = tableLog + 1 - maxW;
576 			U32 consumed;
577 			for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
578 				U32 *const rankValPtr = rankVal[consumed];
579 				U32 w;
580 				for (w = 1; w < maxW + 1; w++) {
581 					rankValPtr[w] = rankVal0[w] >> consumed;
582 				}
583 			}
584 		}
585 	}
586 
587 	HUF_fillDTableX4(dt, maxTableLog, sortedSymbol, sizeOfSort, rankStart0, rankVal, maxW, tableLog + 1);
588 
589 	dtd.tableLog = (BYTE)maxTableLog;
590 	dtd.tableType = 1;
591 	memcpy(DTable, &dtd, sizeof(dtd));
592 	return iSize;
593 }
594 
HUF_decodeSymbolX4(void * op,BIT_DStream_t * DStream,const HUF_DEltX4 * dt,const U32 dtLog)595 static U32 HUF_decodeSymbolX4(void *op, BIT_DStream_t *DStream, const HUF_DEltX4 *dt, const U32 dtLog)
596 {
597 	size_t const val = BIT_lookBitsFast(DStream, dtLog); /* note : dtLog >= 1 */
598 	memcpy(op, dt + val, 2);
599 	BIT_skipBits(DStream, dt[val].nbBits);
600 	return dt[val].length;
601 }
602 
HUF_decodeLastSymbolX4(void * op,BIT_DStream_t * DStream,const HUF_DEltX4 * dt,const U32 dtLog)603 static U32 HUF_decodeLastSymbolX4(void *op, BIT_DStream_t *DStream, const HUF_DEltX4 *dt, const U32 dtLog)
604 {
605 	size_t const val = BIT_lookBitsFast(DStream, dtLog); /* note : dtLog >= 1 */
606 	memcpy(op, dt + val, 1);
607 	if (dt[val].length == 1)
608 		BIT_skipBits(DStream, dt[val].nbBits);
609 	else {
610 		if (DStream->bitsConsumed < (sizeof(DStream->bitContainer) * 8)) {
611 			BIT_skipBits(DStream, dt[val].nbBits);
612 			if (DStream->bitsConsumed > (sizeof(DStream->bitContainer) * 8))
613 				/* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
614 				DStream->bitsConsumed = (sizeof(DStream->bitContainer) * 8);
615 		}
616 	}
617 	return 1;
618 }
619 
620 #define HUF_DECODE_SYMBOLX4_0(ptr, DStreamPtr) ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
621 
622 #define HUF_DECODE_SYMBOLX4_1(ptr, DStreamPtr)         \
623 	if (ZSTD_64bits() || (HUF_TABLELOG_MAX <= 12)) \
624 	ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
625 
626 #define HUF_DECODE_SYMBOLX4_2(ptr, DStreamPtr) \
627 	if (ZSTD_64bits())                     \
628 	ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
629 
HUF_decodeStreamX4(BYTE * p,BIT_DStream_t * bitDPtr,BYTE * const pEnd,const HUF_DEltX4 * const dt,const U32 dtLog)630 FORCE_INLINE size_t HUF_decodeStreamX4(BYTE *p, BIT_DStream_t *bitDPtr, BYTE *const pEnd, const HUF_DEltX4 *const dt, const U32 dtLog)
631 {
632 	BYTE *const pStart = p;
633 
634 	/* up to 8 symbols at a time */
635 	while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd - (sizeof(bitDPtr->bitContainer) - 1))) {
636 		HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
637 		HUF_DECODE_SYMBOLX4_1(p, bitDPtr);
638 		HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
639 		HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
640 	}
641 
642 	/* closer to end : up to 2 symbols at a time */
643 	while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd - 2))
644 		HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
645 
646 	while (p <= pEnd - 2)
647 		HUF_DECODE_SYMBOLX4_0(p, bitDPtr); /* no need to reload : reached the end of DStream */
648 
649 	if (p < pEnd)
650 		p += HUF_decodeLastSymbolX4(p, bitDPtr, dt, dtLog);
651 
652 	return p - pStart;
653 }
654 
HUF_decompress1X4_usingDTable_internal(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)655 static size_t HUF_decompress1X4_usingDTable_internal(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
656 {
657 	BIT_DStream_t bitD;
658 
659 	/* Init */
660 	{
661 		size_t const errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);
662 		if (HUF_isError(errorCode))
663 			return errorCode;
664 	}
665 
666 	/* decode */
667 	{
668 		BYTE *const ostart = (BYTE *)dst;
669 		BYTE *const oend = ostart + dstSize;
670 		const void *const dtPtr = DTable + 1; /* force compiler to not use strict-aliasing */
671 		const HUF_DEltX4 *const dt = (const HUF_DEltX4 *)dtPtr;
672 		DTableDesc const dtd = HUF_getDTableDesc(DTable);
673 		HUF_decodeStreamX4(ostart, &bitD, oend, dt, dtd.tableLog);
674 	}
675 
676 	/* check */
677 	if (!BIT_endOfDStream(&bitD))
678 		return ERROR(corruption_detected);
679 
680 	/* decoded size */
681 	return dstSize;
682 }
683 
HUF_decompress1X4_usingDTable(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)684 size_t HUF_decompress1X4_usingDTable(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
685 {
686 	DTableDesc dtd = HUF_getDTableDesc(DTable);
687 	if (dtd.tableType != 1)
688 		return ERROR(GENERIC);
689 	return HUF_decompress1X4_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable);
690 }
691 
HUF_decompress1X4_DCtx_wksp(HUF_DTable * DCtx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)692 size_t HUF_decompress1X4_DCtx_wksp(HUF_DTable *DCtx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
693 {
694 	const BYTE *ip = (const BYTE *)cSrc;
695 
696 	size_t const hSize = HUF_readDTableX4_wksp(DCtx, cSrc, cSrcSize, workspace, workspaceSize);
697 	if (HUF_isError(hSize))
698 		return hSize;
699 	if (hSize >= cSrcSize)
700 		return ERROR(srcSize_wrong);
701 	ip += hSize;
702 	cSrcSize -= hSize;
703 
704 	return HUF_decompress1X4_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx);
705 }
706 
HUF_decompress4X4_usingDTable_internal(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)707 static size_t HUF_decompress4X4_usingDTable_internal(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
708 {
709 	if (cSrcSize < 10)
710 		return ERROR(corruption_detected); /* strict minimum : jump table + 1 byte per stream */
711 
712 	{
713 		const BYTE *const istart = (const BYTE *)cSrc;
714 		BYTE *const ostart = (BYTE *)dst;
715 		BYTE *const oend = ostart + dstSize;
716 		const void *const dtPtr = DTable + 1;
717 		const HUF_DEltX4 *const dt = (const HUF_DEltX4 *)dtPtr;
718 
719 		/* Init */
720 		BIT_DStream_t bitD1;
721 		BIT_DStream_t bitD2;
722 		BIT_DStream_t bitD3;
723 		BIT_DStream_t bitD4;
724 		size_t const length1 = ZSTD_readLE16(istart);
725 		size_t const length2 = ZSTD_readLE16(istart + 2);
726 		size_t const length3 = ZSTD_readLE16(istart + 4);
727 		size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
728 		const BYTE *const istart1 = istart + 6; /* jumpTable */
729 		const BYTE *const istart2 = istart1 + length1;
730 		const BYTE *const istart3 = istart2 + length2;
731 		const BYTE *const istart4 = istart3 + length3;
732 		size_t const segmentSize = (dstSize + 3) / 4;
733 		BYTE *const opStart2 = ostart + segmentSize;
734 		BYTE *const opStart3 = opStart2 + segmentSize;
735 		BYTE *const opStart4 = opStart3 + segmentSize;
736 		BYTE *op1 = ostart;
737 		BYTE *op2 = opStart2;
738 		BYTE *op3 = opStart3;
739 		BYTE *op4 = opStart4;
740 		U32 endSignal;
741 		DTableDesc const dtd = HUF_getDTableDesc(DTable);
742 		U32 const dtLog = dtd.tableLog;
743 
744 		if (length4 > cSrcSize)
745 			return ERROR(corruption_detected); /* overflow */
746 		{
747 			size_t const errorCode = BIT_initDStream(&bitD1, istart1, length1);
748 			if (HUF_isError(errorCode))
749 				return errorCode;
750 		}
751 		{
752 			size_t const errorCode = BIT_initDStream(&bitD2, istart2, length2);
753 			if (HUF_isError(errorCode))
754 				return errorCode;
755 		}
756 		{
757 			size_t const errorCode = BIT_initDStream(&bitD3, istart3, length3);
758 			if (HUF_isError(errorCode))
759 				return errorCode;
760 		}
761 		{
762 			size_t const errorCode = BIT_initDStream(&bitD4, istart4, length4);
763 			if (HUF_isError(errorCode))
764 				return errorCode;
765 		}
766 
767 		/* 16-32 symbols per loop (4-8 symbols per stream) */
768 		endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
769 		for (; (endSignal == BIT_DStream_unfinished) & (op4 < (oend - (sizeof(bitD4.bitContainer) - 1)));) {
770 			HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
771 			HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
772 			HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
773 			HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
774 			HUF_DECODE_SYMBOLX4_1(op1, &bitD1);
775 			HUF_DECODE_SYMBOLX4_1(op2, &bitD2);
776 			HUF_DECODE_SYMBOLX4_1(op3, &bitD3);
777 			HUF_DECODE_SYMBOLX4_1(op4, &bitD4);
778 			HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
779 			HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
780 			HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
781 			HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
782 			HUF_DECODE_SYMBOLX4_0(op1, &bitD1);
783 			HUF_DECODE_SYMBOLX4_0(op2, &bitD2);
784 			HUF_DECODE_SYMBOLX4_0(op3, &bitD3);
785 			HUF_DECODE_SYMBOLX4_0(op4, &bitD4);
786 
787 			endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
788 		}
789 
790 		/* check corruption */
791 		if (op1 > opStart2)
792 			return ERROR(corruption_detected);
793 		if (op2 > opStart3)
794 			return ERROR(corruption_detected);
795 		if (op3 > opStart4)
796 			return ERROR(corruption_detected);
797 		/* note : op4 already verified within main loop */
798 
799 		/* finish bitStreams one by one */
800 		HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
801 		HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
802 		HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
803 		HUF_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
804 
805 		/* check */
806 		{
807 			U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
808 			if (!endCheck)
809 				return ERROR(corruption_detected);
810 		}
811 
812 		/* decoded size */
813 		return dstSize;
814 	}
815 }
816 
HUF_decompress4X4_usingDTable(void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)817 size_t HUF_decompress4X4_usingDTable(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
818 {
819 	DTableDesc dtd = HUF_getDTableDesc(DTable);
820 	if (dtd.tableType != 1)
821 		return ERROR(GENERIC);
822 	return HUF_decompress4X4_usingDTable_internal(dst, dstSize, cSrc, cSrcSize, DTable);
823 }
824 
HUF_decompress4X4_DCtx_wksp(HUF_DTable * dctx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)825 size_t HUF_decompress4X4_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
826 {
827 	const BYTE *ip = (const BYTE *)cSrc;
828 
829 	size_t hSize = HUF_readDTableX4_wksp(dctx, cSrc, cSrcSize, workspace, workspaceSize);
830 	if (HUF_isError(hSize))
831 		return hSize;
832 	if (hSize >= cSrcSize)
833 		return ERROR(srcSize_wrong);
834 	ip += hSize;
835 	cSrcSize -= hSize;
836 
837 	return HUF_decompress4X4_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx);
838 }
839 
840 /* ********************************/
841 /* Generic decompression selector */
842 /* ********************************/
843 
HUF_decompress1X_usingDTable(void * dst,size_t maxDstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)844 size_t HUF_decompress1X_usingDTable(void *dst, size_t maxDstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
845 {
846 	DTableDesc const dtd = HUF_getDTableDesc(DTable);
847 	return dtd.tableType ? HUF_decompress1X4_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable)
848 			     : HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable);
849 }
850 
HUF_decompress4X_usingDTable(void * dst,size_t maxDstSize,const void * cSrc,size_t cSrcSize,const HUF_DTable * DTable)851 size_t HUF_decompress4X_usingDTable(void *dst, size_t maxDstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
852 {
853 	DTableDesc const dtd = HUF_getDTableDesc(DTable);
854 	return dtd.tableType ? HUF_decompress4X4_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable)
855 			     : HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable);
856 }
857 
858 typedef struct {
859 	U32 tableTime;
860 	U32 decode256Time;
861 } algo_time_t;
862 static const algo_time_t algoTime[16 /* Quantization */][3 /* single, double, quad */] = {
863     /* single, double, quad */
864     {{0, 0}, {1, 1}, {2, 2}},		     /* Q==0 : impossible */
865     {{0, 0}, {1, 1}, {2, 2}},		     /* Q==1 : impossible */
866     {{38, 130}, {1313, 74}, {2151, 38}},     /* Q == 2 : 12-18% */
867     {{448, 128}, {1353, 74}, {2238, 41}},    /* Q == 3 : 18-25% */
868     {{556, 128}, {1353, 74}, {2238, 47}},    /* Q == 4 : 25-32% */
869     {{714, 128}, {1418, 74}, {2436, 53}},    /* Q == 5 : 32-38% */
870     {{883, 128}, {1437, 74}, {2464, 61}},    /* Q == 6 : 38-44% */
871     {{897, 128}, {1515, 75}, {2622, 68}},    /* Q == 7 : 44-50% */
872     {{926, 128}, {1613, 75}, {2730, 75}},    /* Q == 8 : 50-56% */
873     {{947, 128}, {1729, 77}, {3359, 77}},    /* Q == 9 : 56-62% */
874     {{1107, 128}, {2083, 81}, {4006, 84}},   /* Q ==10 : 62-69% */
875     {{1177, 128}, {2379, 87}, {4785, 88}},   /* Q ==11 : 69-75% */
876     {{1242, 128}, {2415, 93}, {5155, 84}},   /* Q ==12 : 75-81% */
877     {{1349, 128}, {2644, 106}, {5260, 106}}, /* Q ==13 : 81-87% */
878     {{1455, 128}, {2422, 124}, {4174, 124}}, /* Q ==14 : 87-93% */
879     {{722, 128}, {1891, 145}, {1936, 146}},  /* Q ==15 : 93-99% */
880 };
881 
882 /** HUF_selectDecoder() :
883 *   Tells which decoder is likely to decode faster,
884 *   based on a set of pre-determined metrics.
885 *   @return : 0==HUF_decompress4X2, 1==HUF_decompress4X4 .
886 *   Assumption : 0 < cSrcSize < dstSize <= 128 KB */
HUF_selectDecoder(size_t dstSize,size_t cSrcSize)887 U32 HUF_selectDecoder(size_t dstSize, size_t cSrcSize)
888 {
889 	/* decoder timing evaluation */
890 	U32 const Q = (U32)(cSrcSize * 16 / dstSize); /* Q < 16 since dstSize > cSrcSize */
891 	U32 const D256 = (U32)(dstSize >> 8);
892 	U32 const DTime0 = algoTime[Q][0].tableTime + (algoTime[Q][0].decode256Time * D256);
893 	U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * D256);
894 	DTime1 += DTime1 >> 3; /* advantage to algorithm using less memory, for cache eviction */
895 
896 	return DTime1 < DTime0;
897 }
898 
899 typedef size_t (*decompressionAlgo)(void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize);
900 
HUF_decompress4X_DCtx_wksp(HUF_DTable * dctx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)901 size_t HUF_decompress4X_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
902 {
903 	/* validation checks */
904 	if (dstSize == 0)
905 		return ERROR(dstSize_tooSmall);
906 	if (cSrcSize > dstSize)
907 		return ERROR(corruption_detected); /* invalid */
908 	if (cSrcSize == dstSize) {
909 		memcpy(dst, cSrc, dstSize);
910 		return dstSize;
911 	} /* not compressed */
912 	if (cSrcSize == 1) {
913 		memset(dst, *(const BYTE *)cSrc, dstSize);
914 		return dstSize;
915 	} /* RLE */
916 
917 	{
918 		U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
919 		return algoNb ? HUF_decompress4X4_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workspace, workspaceSize)
920 			      : HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workspace, workspaceSize);
921 	}
922 }
923 
HUF_decompress4X_hufOnly_wksp(HUF_DTable * dctx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)924 size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
925 {
926 	/* validation checks */
927 	if (dstSize == 0)
928 		return ERROR(dstSize_tooSmall);
929 	if ((cSrcSize >= dstSize) || (cSrcSize <= 1))
930 		return ERROR(corruption_detected); /* invalid */
931 
932 	{
933 		U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
934 		return algoNb ? HUF_decompress4X4_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workspace, workspaceSize)
935 			      : HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workspace, workspaceSize);
936 	}
937 }
938 
HUF_decompress1X_DCtx_wksp(HUF_DTable * dctx,void * dst,size_t dstSize,const void * cSrc,size_t cSrcSize,void * workspace,size_t workspaceSize)939 size_t HUF_decompress1X_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
940 {
941 	/* validation checks */
942 	if (dstSize == 0)
943 		return ERROR(dstSize_tooSmall);
944 	if (cSrcSize > dstSize)
945 		return ERROR(corruption_detected); /* invalid */
946 	if (cSrcSize == dstSize) {
947 		memcpy(dst, cSrc, dstSize);
948 		return dstSize;
949 	} /* not compressed */
950 	if (cSrcSize == 1) {
951 		memset(dst, *(const BYTE *)cSrc, dstSize);
952 		return dstSize;
953 	} /* RLE */
954 
955 	{
956 		U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
957 		return algoNb ? HUF_decompress1X4_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workspace, workspaceSize)
958 			      : HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workspace, workspaceSize);
959 	}
960 }
961