blob: e32e542e021a9c75a2456d6262b97fff20b80b24 [file] [log] [blame]
Takahiro Suzukid7bf8202020-12-17 20:21:59 +09001/*
2 * Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11#include "zstd_compress_internal.h"
12#include "hist.h"
13#include "zstd_opt.h"
14
15
16#define ZSTD_LITFREQ_ADD 2 /* scaling factor for litFreq, so that frequencies adapt faster to new stats */
17#define ZSTD_FREQ_DIV 4 /* log factor when using previous stats to init next stats */
18#define ZSTD_MAX_PRICE (1<<30)
19
20#define ZSTD_PREDEF_THRESHOLD 1024 /* if srcSize < ZSTD_PREDEF_THRESHOLD, symbols' cost is assumed static, directly determined by pre-defined distributions */
21
22
23/*-*************************************
24* Price functions for optimal parser
25***************************************/
26
27#if 0 /* approximation at bit level */
28# define BITCOST_ACCURACY 0
29# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
30# define WEIGHT(stat) ((void)opt, ZSTD_bitWeight(stat))
31#elif 0 /* fractional bit accuracy */
32# define BITCOST_ACCURACY 8
33# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
34# define WEIGHT(stat,opt) ((void)opt, ZSTD_fracWeight(stat))
35#else /* opt==approx, ultra==accurate */
36# define BITCOST_ACCURACY 8
37# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
38# define WEIGHT(stat,opt) (opt ? ZSTD_fracWeight(stat) : ZSTD_bitWeight(stat))
39#endif
40
41MEM_STATIC U32 ZSTD_bitWeight(U32 stat)
42{
43 return (ZSTD_highbit32(stat+1) * BITCOST_MULTIPLIER);
44}
45
46MEM_STATIC U32 ZSTD_fracWeight(U32 rawStat)
47{
48 U32 const stat = rawStat + 1;
49 U32 const hb = ZSTD_highbit32(stat);
50 U32 const BWeight = hb * BITCOST_MULTIPLIER;
51 U32 const FWeight = (stat << BITCOST_ACCURACY) >> hb;
52 U32 const weight = BWeight + FWeight;
53 assert(hb + BITCOST_ACCURACY < 31);
54 return weight;
55}
56
57#if (DEBUGLEVEL>=2)
58/* debugging function,
59 * @return price in bytes as fractional value
60 * for debug messages only */
61MEM_STATIC double ZSTD_fCost(U32 price)
62{
63 return (double)price / (BITCOST_MULTIPLIER*8);
64}
65#endif
66
67static int ZSTD_compressedLiterals(optState_t const* const optPtr)
68{
69 return optPtr->literalCompressionMode != ZSTD_lcm_uncompressed;
70}
71
72static void ZSTD_setBasePrices(optState_t* optPtr, int optLevel)
73{
74 if (ZSTD_compressedLiterals(optPtr))
75 optPtr->litSumBasePrice = WEIGHT(optPtr->litSum, optLevel);
76 optPtr->litLengthSumBasePrice = WEIGHT(optPtr->litLengthSum, optLevel);
77 optPtr->matchLengthSumBasePrice = WEIGHT(optPtr->matchLengthSum, optLevel);
78 optPtr->offCodeSumBasePrice = WEIGHT(optPtr->offCodeSum, optLevel);
79}
80
81
82/* ZSTD_downscaleStat() :
83 * reduce all elements in table by a factor 2^(ZSTD_FREQ_DIV+malus)
84 * return the resulting sum of elements */
85static U32 ZSTD_downscaleStat(unsigned* table, U32 lastEltIndex, int malus)
86{
87 U32 s, sum=0;
88 DEBUGLOG(5, "ZSTD_downscaleStat (nbElts=%u)", (unsigned)lastEltIndex+1);
89 assert(ZSTD_FREQ_DIV+malus > 0 && ZSTD_FREQ_DIV+malus < 31);
90 for (s=0; s<lastEltIndex+1; s++) {
91 table[s] = 1 + (table[s] >> (ZSTD_FREQ_DIV+malus));
92 sum += table[s];
93 }
94 return sum;
95}
96
97/* ZSTD_rescaleFreqs() :
98 * if first block (detected by optPtr->litLengthSum == 0) : init statistics
99 * take hints from dictionary if there is one
100 * or init from zero, using src for literals stats, or flat 1 for match symbols
101 * otherwise downscale existing stats, to be used as seed for next block.
102 */
103static void
104ZSTD_rescaleFreqs(optState_t* const optPtr,
105 const BYTE* const src, size_t const srcSize,
106 int const optLevel)
107{
108 int const compressedLiterals = ZSTD_compressedLiterals(optPtr);
109 DEBUGLOG(5, "ZSTD_rescaleFreqs (srcSize=%u)", (unsigned)srcSize);
110 optPtr->priceType = zop_dynamic;
111
112 if (optPtr->litLengthSum == 0) { /* first block : init */
113 if (srcSize <= ZSTD_PREDEF_THRESHOLD) { /* heuristic */
114 DEBUGLOG(5, "(srcSize <= ZSTD_PREDEF_THRESHOLD) => zop_predef");
115 optPtr->priceType = zop_predef;
116 }
117
118 assert(optPtr->symbolCosts != NULL);
119 if (optPtr->symbolCosts->huf.repeatMode == HUF_repeat_valid) {
120 /* huffman table presumed generated by dictionary */
121 optPtr->priceType = zop_dynamic;
122
123 if (compressedLiterals) {
124 unsigned lit;
125 assert(optPtr->litFreq != NULL);
126 optPtr->litSum = 0;
127 for (lit=0; lit<=MaxLit; lit++) {
128 U32 const scaleLog = 11; /* scale to 2K */
129 U32 const bitCost = HUF_getNbBits(optPtr->symbolCosts->huf.CTable, lit);
130 assert(bitCost <= scaleLog);
131 optPtr->litFreq[lit] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/;
132 optPtr->litSum += optPtr->litFreq[lit];
133 } }
134
135 { unsigned ll;
136 FSE_CState_t llstate;
137 FSE_initCState(&llstate, optPtr->symbolCosts->fse.litlengthCTable);
138 optPtr->litLengthSum = 0;
139 for (ll=0; ll<=MaxLL; ll++) {
140 U32 const scaleLog = 10; /* scale to 1K */
141 U32 const bitCost = FSE_getMaxNbBits(llstate.symbolTT, ll);
142 assert(bitCost < scaleLog);
143 optPtr->litLengthFreq[ll] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/;
144 optPtr->litLengthSum += optPtr->litLengthFreq[ll];
145 } }
146
147 { unsigned ml;
148 FSE_CState_t mlstate;
149 FSE_initCState(&mlstate, optPtr->symbolCosts->fse.matchlengthCTable);
150 optPtr->matchLengthSum = 0;
151 for (ml=0; ml<=MaxML; ml++) {
152 U32 const scaleLog = 10;
153 U32 const bitCost = FSE_getMaxNbBits(mlstate.symbolTT, ml);
154 assert(bitCost < scaleLog);
155 optPtr->matchLengthFreq[ml] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/;
156 optPtr->matchLengthSum += optPtr->matchLengthFreq[ml];
157 } }
158
159 { unsigned of;
160 FSE_CState_t ofstate;
161 FSE_initCState(&ofstate, optPtr->symbolCosts->fse.offcodeCTable);
162 optPtr->offCodeSum = 0;
163 for (of=0; of<=MaxOff; of++) {
164 U32 const scaleLog = 10;
165 U32 const bitCost = FSE_getMaxNbBits(ofstate.symbolTT, of);
166 assert(bitCost < scaleLog);
167 optPtr->offCodeFreq[of] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/;
168 optPtr->offCodeSum += optPtr->offCodeFreq[of];
169 } }
170
171 } else { /* not a dictionary */
172
173 assert(optPtr->litFreq != NULL);
174 if (compressedLiterals) {
175 unsigned lit = MaxLit;
176 HIST_count_simple(optPtr->litFreq, &lit, src, srcSize); /* use raw first block to init statistics */
177 optPtr->litSum = ZSTD_downscaleStat(optPtr->litFreq, MaxLit, 1);
178 }
179
180 { unsigned ll;
181 for (ll=0; ll<=MaxLL; ll++)
182 optPtr->litLengthFreq[ll] = 1;
183 }
184 optPtr->litLengthSum = MaxLL+1;
185
186 { unsigned ml;
187 for (ml=0; ml<=MaxML; ml++)
188 optPtr->matchLengthFreq[ml] = 1;
189 }
190 optPtr->matchLengthSum = MaxML+1;
191
192 { unsigned of;
193 for (of=0; of<=MaxOff; of++)
194 optPtr->offCodeFreq[of] = 1;
195 }
196 optPtr->offCodeSum = MaxOff+1;
197
198 }
199
200 } else { /* new block : re-use previous statistics, scaled down */
201
202 if (compressedLiterals)
203 optPtr->litSum = ZSTD_downscaleStat(optPtr->litFreq, MaxLit, 1);
204 optPtr->litLengthSum = ZSTD_downscaleStat(optPtr->litLengthFreq, MaxLL, 0);
205 optPtr->matchLengthSum = ZSTD_downscaleStat(optPtr->matchLengthFreq, MaxML, 0);
206 optPtr->offCodeSum = ZSTD_downscaleStat(optPtr->offCodeFreq, MaxOff, 0);
207 }
208
209 ZSTD_setBasePrices(optPtr, optLevel);
210}
211
212/* ZSTD_rawLiteralsCost() :
213 * price of literals (only) in specified segment (which length can be 0).
214 * does not include price of literalLength symbol */
215static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength,
216 const optState_t* const optPtr,
217 int optLevel)
218{
219 if (litLength == 0) return 0;
220
221 if (!ZSTD_compressedLiterals(optPtr))
222 return (litLength << 3) * BITCOST_MULTIPLIER; /* Uncompressed - 8 bytes per literal. */
223
224 if (optPtr->priceType == zop_predef)
225 return (litLength*6) * BITCOST_MULTIPLIER; /* 6 bit per literal - no statistic used */
226
227 /* dynamic statistics */
228 { U32 price = litLength * optPtr->litSumBasePrice;
229 U32 u;
230 for (u=0; u < litLength; u++) {
231 assert(WEIGHT(optPtr->litFreq[literals[u]], optLevel) <= optPtr->litSumBasePrice); /* literal cost should never be negative */
232 price -= WEIGHT(optPtr->litFreq[literals[u]], optLevel);
233 }
234 return price;
235 }
236}
237
238/* ZSTD_litLengthPrice() :
239 * cost of literalLength symbol */
240static U32 ZSTD_litLengthPrice(U32 const litLength, const optState_t* const optPtr, int optLevel)
241{
242 if (optPtr->priceType == zop_predef) return WEIGHT(litLength, optLevel);
243
244 /* dynamic statistics */
245 { U32 const llCode = ZSTD_LLcode(litLength);
246 return (LL_bits[llCode] * BITCOST_MULTIPLIER)
247 + optPtr->litLengthSumBasePrice
248 - WEIGHT(optPtr->litLengthFreq[llCode], optLevel);
249 }
250}
251
252/* ZSTD_litLengthContribution() :
253 * @return ( cost(litlength) - cost(0) )
254 * this value can then be added to rawLiteralsCost()
255 * to provide a cost which is directly comparable to a match ending at same position */
256static int ZSTD_litLengthContribution(U32 const litLength, const optState_t* const optPtr, int optLevel)
257{
258 if (optPtr->priceType >= zop_predef) return (int)WEIGHT(litLength, optLevel);
259
260 /* dynamic statistics */
261 { U32 const llCode = ZSTD_LLcode(litLength);
262 int const contribution = (int)(LL_bits[llCode] * BITCOST_MULTIPLIER)
263 + (int)WEIGHT(optPtr->litLengthFreq[0], optLevel) /* note: log2litLengthSum cancel out */
264 - (int)WEIGHT(optPtr->litLengthFreq[llCode], optLevel);
265#if 1
266 return contribution;
267#else
268 return MAX(0, contribution); /* sometimes better, sometimes not ... */
269#endif
270 }
271}
272
273/* ZSTD_literalsContribution() :
274 * creates a fake cost for the literals part of a sequence
275 * which can be compared to the ending cost of a match
276 * should a new match start at this position */
277static int ZSTD_literalsContribution(const BYTE* const literals, U32 const litLength,
278 const optState_t* const optPtr,
279 int optLevel)
280{
281 int const contribution = (int)ZSTD_rawLiteralsCost(literals, litLength, optPtr, optLevel)
282 + ZSTD_litLengthContribution(litLength, optPtr, optLevel);
283 return contribution;
284}
285
286/* ZSTD_getMatchPrice() :
287 * Provides the cost of the match part (offset + matchLength) of a sequence
288 * Must be combined with ZSTD_fullLiteralsCost() to get the full cost of a sequence.
289 * optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */
290FORCE_INLINE_TEMPLATE U32
291ZSTD_getMatchPrice(U32 const offset,
292 U32 const matchLength,
293 const optState_t* const optPtr,
294 int const optLevel)
295{
296 U32 price;
297 U32 const offCode = ZSTD_highbit32(offset+1);
298 U32 const mlBase = matchLength - MINMATCH;
299 assert(matchLength >= MINMATCH);
300
301 if (optPtr->priceType == zop_predef) /* fixed scheme, do not use statistics */
302 return WEIGHT(mlBase, optLevel) + ((16 + offCode) * BITCOST_MULTIPLIER);
303
304 /* dynamic statistics */
305 price = (offCode * BITCOST_MULTIPLIER) + (optPtr->offCodeSumBasePrice - WEIGHT(optPtr->offCodeFreq[offCode], optLevel));
306 if ((optLevel<2) /*static*/ && offCode >= 20)
307 price += (offCode-19)*2 * BITCOST_MULTIPLIER; /* handicap for long distance offsets, favor decompression speed */
308
309 /* match Length */
310 { U32 const mlCode = ZSTD_MLcode(mlBase);
311 price += (ML_bits[mlCode] * BITCOST_MULTIPLIER) + (optPtr->matchLengthSumBasePrice - WEIGHT(optPtr->matchLengthFreq[mlCode], optLevel));
312 }
313
314 price += BITCOST_MULTIPLIER / 5; /* heuristic : make matches a bit more costly to favor less sequences -> faster decompression speed */
315
316 DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price);
317 return price;
318}
319
320/* ZSTD_updateStats() :
321 * assumption : literals + litLengtn <= iend */
322static void ZSTD_updateStats(optState_t* const optPtr,
323 U32 litLength, const BYTE* literals,
324 U32 offsetCode, U32 matchLength)
325{
326 /* literals */
327 if (ZSTD_compressedLiterals(optPtr)) {
328 U32 u;
329 for (u=0; u < litLength; u++)
330 optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
331 optPtr->litSum += litLength*ZSTD_LITFREQ_ADD;
332 }
333
334 /* literal Length */
335 { U32 const llCode = ZSTD_LLcode(litLength);
336 optPtr->litLengthFreq[llCode]++;
337 optPtr->litLengthSum++;
338 }
339
340 /* match offset code (0-2=>repCode; 3+=>offset+2) */
341 { U32 const offCode = ZSTD_highbit32(offsetCode+1);
342 assert(offCode <= MaxOff);
343 optPtr->offCodeFreq[offCode]++;
344 optPtr->offCodeSum++;
345 }
346
347 /* match Length */
348 { U32 const mlBase = matchLength - MINMATCH;
349 U32 const mlCode = ZSTD_MLcode(mlBase);
350 optPtr->matchLengthFreq[mlCode]++;
351 optPtr->matchLengthSum++;
352 }
353}
354
355
356/* ZSTD_readMINMATCH() :
357 * function safe only for comparisons
358 * assumption : memPtr must be at least 4 bytes before end of buffer */
359MEM_STATIC U32 ZSTD_readMINMATCH(const void* memPtr, U32 length)
360{
361 switch (length)
362 {
363 default :
364 case 4 : return MEM_read32(memPtr);
365 case 3 : if (MEM_isLittleEndian())
366 return MEM_read32(memPtr)<<8;
367 else
368 return MEM_read32(memPtr)>>8;
369 }
370}
371
372
373/* Update hashTable3 up to ip (excluded)
374 Assumption : always within prefix (i.e. not within extDict) */
375static U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_matchState_t* ms,
376 U32* nextToUpdate3,
377 const BYTE* const ip)
378{
379 U32* const hashTable3 = ms->hashTable3;
380 U32 const hashLog3 = ms->hashLog3;
381 const BYTE* const base = ms->window.base;
382 U32 idx = *nextToUpdate3;
383 U32 const target = (U32)(ip - base);
384 size_t const hash3 = ZSTD_hash3Ptr(ip, hashLog3);
385 assert(hashLog3 > 0);
386
387 while(idx < target) {
388 hashTable3[ZSTD_hash3Ptr(base+idx, hashLog3)] = idx;
389 idx++;
390 }
391
392 *nextToUpdate3 = target;
393 return hashTable3[hash3];
394}
395
396
397/*-*************************************
398* Binary Tree search
399***************************************/
400/** ZSTD_insertBt1() : add one or multiple positions to tree.
401 * ip : assumed <= iend-8 .
402 * @return : nb of positions added */
403static U32 ZSTD_insertBt1(
404 ZSTD_matchState_t* ms,
405 const BYTE* const ip, const BYTE* const iend,
406 U32 const mls, const int extDict)
407{
408 const ZSTD_compressionParameters* const cParams = &ms->cParams;
409 U32* const hashTable = ms->hashTable;
410 U32 const hashLog = cParams->hashLog;
411 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
412 U32* const bt = ms->chainTable;
413 U32 const btLog = cParams->chainLog - 1;
414 U32 const btMask = (1 << btLog) - 1;
415 U32 matchIndex = hashTable[h];
416 size_t commonLengthSmaller=0, commonLengthLarger=0;
417 const BYTE* const base = ms->window.base;
418 const BYTE* const dictBase = ms->window.dictBase;
419 const U32 dictLimit = ms->window.dictLimit;
420 const BYTE* const dictEnd = dictBase + dictLimit;
421 const BYTE* const prefixStart = base + dictLimit;
422 const BYTE* match;
423 const U32 current = (U32)(ip-base);
424 const U32 btLow = btMask >= current ? 0 : current - btMask;
425 U32* smallerPtr = bt + 2*(current&btMask);
426 U32* largerPtr = smallerPtr + 1;
427 U32 dummy32; /* to be nullified at the end */
428 U32 const windowLow = ms->window.lowLimit;
429 U32 matchEndIdx = current+8+1;
430 size_t bestLength = 8;
431 U32 nbCompares = 1U << cParams->searchLog;
432#ifdef ZSTD_C_PREDICT
433 U32 predictedSmall = *(bt + 2*((current-1)&btMask) + 0);
434 U32 predictedLarge = *(bt + 2*((current-1)&btMask) + 1);
435 predictedSmall += (predictedSmall>0);
436 predictedLarge += (predictedLarge>0);
437#endif /* ZSTD_C_PREDICT */
438
439 DEBUGLOG(8, "ZSTD_insertBt1 (%u)", current);
440
441 assert(ip <= iend-8); /* required for h calculation */
442 hashTable[h] = current; /* Update Hash Table */
443
444 assert(windowLow > 0);
445 while (nbCompares-- && (matchIndex >= windowLow)) {
446 U32* const nextPtr = bt + 2*(matchIndex & btMask);
447 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
448 assert(matchIndex < current);
449
450#ifdef ZSTD_C_PREDICT /* note : can create issues when hlog small <= 11 */
451 const U32* predictPtr = bt + 2*((matchIndex-1) & btMask); /* written this way, as bt is a roll buffer */
452 if (matchIndex == predictedSmall) {
453 /* no need to check length, result known */
454 *smallerPtr = matchIndex;
455 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
456 smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
457 matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
458 predictedSmall = predictPtr[1] + (predictPtr[1]>0);
459 continue;
460 }
461 if (matchIndex == predictedLarge) {
462 *largerPtr = matchIndex;
463 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
464 largerPtr = nextPtr;
465 matchIndex = nextPtr[0];
466 predictedLarge = predictPtr[0] + (predictPtr[0]>0);
467 continue;
468 }
469#endif
470
471 if (!extDict || (matchIndex+matchLength >= dictLimit)) {
472 assert(matchIndex+matchLength >= dictLimit); /* might be wrong if actually extDict */
473 match = base + matchIndex;
474 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
475 } else {
476 match = dictBase + matchIndex;
477 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
478 if (matchIndex+matchLength >= dictLimit)
479 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
480 }
481
482 if (matchLength > bestLength) {
483 bestLength = matchLength;
484 if (matchLength > matchEndIdx - matchIndex)
485 matchEndIdx = matchIndex + (U32)matchLength;
486 }
487
488 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
489 break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
490 }
491
492 if (match[matchLength] < ip[matchLength]) { /* necessarily within buffer */
493 /* match is smaller than current */
494 *smallerPtr = matchIndex; /* update smaller idx */
495 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
496 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop searching */
497 smallerPtr = nextPtr+1; /* new "candidate" => larger than match, which was smaller than target */
498 matchIndex = nextPtr[1]; /* new matchIndex, larger than previous and closer to current */
499 } else {
500 /* match is larger than current */
501 *largerPtr = matchIndex;
502 commonLengthLarger = matchLength;
503 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop searching */
504 largerPtr = nextPtr;
505 matchIndex = nextPtr[0];
506 } }
507
508 *smallerPtr = *largerPtr = 0;
509 { U32 positions = 0;
510 if (bestLength > 384) positions = MIN(192, (U32)(bestLength - 384)); /* speed optimization */
511 assert(matchEndIdx > current + 8);
512 return MAX(positions, matchEndIdx - (current + 8));
513 }
514}
515
516FORCE_INLINE_TEMPLATE
517void ZSTD_updateTree_internal(
518 ZSTD_matchState_t* ms,
519 const BYTE* const ip, const BYTE* const iend,
520 const U32 mls, const ZSTD_dictMode_e dictMode)
521{
522 const BYTE* const base = ms->window.base;
523 U32 const target = (U32)(ip - base);
524 U32 idx = ms->nextToUpdate;
525 DEBUGLOG(6, "ZSTD_updateTree_internal, from %u to %u (dictMode:%u)",
526 idx, target, dictMode);
527
528 while(idx < target) {
529 U32 const forward = ZSTD_insertBt1(ms, base+idx, iend, mls, dictMode == ZSTD_extDict);
530 assert(idx < (U32)(idx + forward));
531 idx += forward;
532 }
533 assert((size_t)(ip - base) <= (size_t)(U32)(-1));
534 assert((size_t)(iend - base) <= (size_t)(U32)(-1));
535 ms->nextToUpdate = target;
536}
537
538void ZSTD_updateTree(ZSTD_matchState_t* ms, const BYTE* ip, const BYTE* iend) {
539 ZSTD_updateTree_internal(ms, ip, iend, ms->cParams.minMatch, ZSTD_noDict);
540}
541
542FORCE_INLINE_TEMPLATE
543U32 ZSTD_insertBtAndGetAllMatches (
544 ZSTD_match_t* matches, /* store result (found matches) in this table (presumed large enough) */
545 ZSTD_matchState_t* ms,
546 U32* nextToUpdate3,
547 const BYTE* const ip, const BYTE* const iLimit, const ZSTD_dictMode_e dictMode,
548 const U32 rep[ZSTD_REP_NUM],
549 U32 const ll0, /* tells if associated literal length is 0 or not. This value must be 0 or 1 */
550 const U32 lengthToBeat,
551 U32 const mls /* template */)
552{
553 const ZSTD_compressionParameters* const cParams = &ms->cParams;
554 U32 const sufficient_len = MIN(cParams->targetLength, ZSTD_OPT_NUM -1);
555 U32 const maxDistance = 1U << cParams->windowLog;
556 const BYTE* const base = ms->window.base;
557 U32 const current = (U32)(ip-base);
558 U32 const hashLog = cParams->hashLog;
559 U32 const minMatch = (mls==3) ? 3 : 4;
560 U32* const hashTable = ms->hashTable;
561 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
562 U32 matchIndex = hashTable[h];
563 U32* const bt = ms->chainTable;
564 U32 const btLog = cParams->chainLog - 1;
565 U32 const btMask= (1U << btLog) - 1;
566 size_t commonLengthSmaller=0, commonLengthLarger=0;
567 const BYTE* const dictBase = ms->window.dictBase;
568 U32 const dictLimit = ms->window.dictLimit;
569 const BYTE* const dictEnd = dictBase + dictLimit;
570 const BYTE* const prefixStart = base + dictLimit;
571 U32 const btLow = (btMask >= current) ? 0 : current - btMask;
572 U32 const windowValid = ms->window.lowLimit;
573 U32 const windowLow = ((current - windowValid) > maxDistance) ? current - maxDistance : windowValid;
574 U32 const matchLow = windowLow ? windowLow : 1;
575 U32* smallerPtr = bt + 2*(current&btMask);
576 U32* largerPtr = bt + 2*(current&btMask) + 1;
577 U32 matchEndIdx = current+8+1; /* farthest referenced position of any match => detects repetitive patterns */
578 U32 dummy32; /* to be nullified at the end */
579 U32 mnum = 0;
580 U32 nbCompares = 1U << cParams->searchLog;
581
582 const ZSTD_matchState_t* dms = dictMode == ZSTD_dictMatchState ? ms->dictMatchState : NULL;
583 const ZSTD_compressionParameters* const dmsCParams =
584 dictMode == ZSTD_dictMatchState ? &dms->cParams : NULL;
585 const BYTE* const dmsBase = dictMode == ZSTD_dictMatchState ? dms->window.base : NULL;
586 const BYTE* const dmsEnd = dictMode == ZSTD_dictMatchState ? dms->window.nextSrc : NULL;
587 U32 const dmsHighLimit = dictMode == ZSTD_dictMatchState ? (U32)(dmsEnd - dmsBase) : 0;
588 U32 const dmsLowLimit = dictMode == ZSTD_dictMatchState ? dms->window.lowLimit : 0;
589 U32 const dmsIndexDelta = dictMode == ZSTD_dictMatchState ? windowLow - dmsHighLimit : 0;
590 U32 const dmsHashLog = dictMode == ZSTD_dictMatchState ? dmsCParams->hashLog : hashLog;
591 U32 const dmsBtLog = dictMode == ZSTD_dictMatchState ? dmsCParams->chainLog - 1 : btLog;
592 U32 const dmsBtMask = dictMode == ZSTD_dictMatchState ? (1U << dmsBtLog) - 1 : 0;
593 U32 const dmsBtLow = dictMode == ZSTD_dictMatchState && dmsBtMask < dmsHighLimit - dmsLowLimit ? dmsHighLimit - dmsBtMask : dmsLowLimit;
594
595 size_t bestLength = lengthToBeat-1;
596 DEBUGLOG(8, "ZSTD_insertBtAndGetAllMatches: current=%u", current);
597
598 /* check repCode */
599 assert(ll0 <= 1); /* necessarily 1 or 0 */
600 { U32 const lastR = ZSTD_REP_NUM + ll0;
601 U32 repCode;
602 for (repCode = ll0; repCode < lastR; repCode++) {
603 U32 const repOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
604 U32 const repIndex = current - repOffset;
605 U32 repLen = 0;
606 assert(current >= dictLimit);
607 if (repOffset-1 /* intentional overflow, discards 0 and -1 */ < current-dictLimit) { /* equivalent to `current > repIndex >= dictLimit` */
608 if (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repOffset, minMatch)) {
609 repLen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repOffset, iLimit) + minMatch;
610 }
611 } else { /* repIndex < dictLimit || repIndex >= current */
612 const BYTE* const repMatch = dictMode == ZSTD_dictMatchState ?
613 dmsBase + repIndex - dmsIndexDelta :
614 dictBase + repIndex;
615 assert(current >= windowLow);
616 if ( dictMode == ZSTD_extDict
617 && ( ((repOffset-1) /*intentional overflow*/ < current - windowLow) /* equivalent to `current > repIndex >= windowLow` */
618 & (((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */)
619 && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
620 repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dictEnd, prefixStart) + minMatch;
621 }
622 if (dictMode == ZSTD_dictMatchState
623 && ( ((repOffset-1) /*intentional overflow*/ < current - (dmsLowLimit + dmsIndexDelta)) /* equivalent to `current > repIndex >= dmsLowLimit` */
624 & ((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */
625 && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
626 repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dmsEnd, prefixStart) + minMatch;
627 } }
628 /* save longer solution */
629 if (repLen > bestLength) {
630 DEBUGLOG(8, "found repCode %u (ll0:%u, offset:%u) of length %u",
631 repCode, ll0, repOffset, repLen);
632 bestLength = repLen;
633 matches[mnum].off = repCode - ll0;
634 matches[mnum].len = (U32)repLen;
635 mnum++;
636 if ( (repLen > sufficient_len)
637 | (ip+repLen == iLimit) ) { /* best possible */
638 return mnum;
639 } } } }
640
641 /* HC3 match finder */
642 if ((mls == 3) /*static*/ && (bestLength < mls)) {
643 U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3(ms, nextToUpdate3, ip);
644 if ((matchIndex3 >= matchLow)
645 & (current - matchIndex3 < (1<<18)) /*heuristic : longer distance likely too expensive*/ ) {
646 size_t mlen;
647 if ((dictMode == ZSTD_noDict) /*static*/ || (dictMode == ZSTD_dictMatchState) /*static*/ || (matchIndex3 >= dictLimit)) {
648 const BYTE* const match = base + matchIndex3;
649 mlen = ZSTD_count(ip, match, iLimit);
650 } else {
651 const BYTE* const match = dictBase + matchIndex3;
652 mlen = ZSTD_count_2segments(ip, match, iLimit, dictEnd, prefixStart);
653 }
654
655 /* save best solution */
656 if (mlen >= mls /* == 3 > bestLength */) {
657 DEBUGLOG(8, "found small match with hlog3, of length %u",
658 (U32)mlen);
659 bestLength = mlen;
660 assert(current > matchIndex3);
661 assert(mnum==0); /* no prior solution */
662 matches[0].off = (current - matchIndex3) + ZSTD_REP_MOVE;
663 matches[0].len = (U32)mlen;
664 mnum = 1;
665 if ( (mlen > sufficient_len) |
666 (ip+mlen == iLimit) ) { /* best possible length */
667 ms->nextToUpdate = current+1; /* skip insertion */
668 return 1;
669 } } }
670 /* no dictMatchState lookup: dicts don't have a populated HC3 table */
671 }
672
673 hashTable[h] = current; /* Update Hash Table */
674
675 while (nbCompares-- && (matchIndex >= matchLow)) {
676 U32* const nextPtr = bt + 2*(matchIndex & btMask);
677 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
678 const BYTE* match;
679 assert(current > matchIndex);
680
681 if ((dictMode == ZSTD_noDict) || (dictMode == ZSTD_dictMatchState) || (matchIndex+matchLength >= dictLimit)) {
682 assert(matchIndex+matchLength >= dictLimit); /* ensure the condition is correct when !extDict */
683 match = base + matchIndex;
684 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iLimit);
685 } else {
686 match = dictBase + matchIndex;
687 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dictEnd, prefixStart);
688 if (matchIndex+matchLength >= dictLimit)
689 match = base + matchIndex; /* prepare for match[matchLength] */
690 }
691
692 if (matchLength > bestLength) {
693 DEBUGLOG(8, "found match of length %u at distance %u (offCode=%u)",
694 (U32)matchLength, current - matchIndex, current - matchIndex + ZSTD_REP_MOVE);
695 assert(matchEndIdx > matchIndex);
696 if (matchLength > matchEndIdx - matchIndex)
697 matchEndIdx = matchIndex + (U32)matchLength;
698 bestLength = matchLength;
699 matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE;
700 matches[mnum].len = (U32)matchLength;
701 mnum++;
702 if ( (matchLength > ZSTD_OPT_NUM)
703 | (ip+matchLength == iLimit) /* equal : no way to know if inf or sup */) {
704 if (dictMode == ZSTD_dictMatchState) nbCompares = 0; /* break should also skip searching dms */
705 break; /* drop, to preserve bt consistency (miss a little bit of compression) */
706 }
707 }
708
709 if (match[matchLength] < ip[matchLength]) {
710 /* match smaller than current */
711 *smallerPtr = matchIndex; /* update smaller idx */
712 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
713 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
714 smallerPtr = nextPtr+1; /* new candidate => larger than match, which was smaller than current */
715 matchIndex = nextPtr[1]; /* new matchIndex, larger than previous, closer to current */
716 } else {
717 *largerPtr = matchIndex;
718 commonLengthLarger = matchLength;
719 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
720 largerPtr = nextPtr;
721 matchIndex = nextPtr[0];
722 } }
723
724 *smallerPtr = *largerPtr = 0;
725
726 if (dictMode == ZSTD_dictMatchState && nbCompares) {
727 size_t const dmsH = ZSTD_hashPtr(ip, dmsHashLog, mls);
728 U32 dictMatchIndex = dms->hashTable[dmsH];
729 const U32* const dmsBt = dms->chainTable;
730 commonLengthSmaller = commonLengthLarger = 0;
731 while (nbCompares-- && (dictMatchIndex > dmsLowLimit)) {
732 const U32* const nextPtr = dmsBt + 2*(dictMatchIndex & dmsBtMask);
733 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
734 const BYTE* match = dmsBase + dictMatchIndex;
735 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dmsEnd, prefixStart);
736 if (dictMatchIndex+matchLength >= dmsHighLimit)
737 match = base + dictMatchIndex + dmsIndexDelta; /* to prepare for next usage of match[matchLength] */
738
739 if (matchLength > bestLength) {
740 matchIndex = dictMatchIndex + dmsIndexDelta;
741 DEBUGLOG(8, "found dms match of length %u at distance %u (offCode=%u)",
742 (U32)matchLength, current - matchIndex, current - matchIndex + ZSTD_REP_MOVE);
743 if (matchLength > matchEndIdx - matchIndex)
744 matchEndIdx = matchIndex + (U32)matchLength;
745 bestLength = matchLength;
746 matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE;
747 matches[mnum].len = (U32)matchLength;
748 mnum++;
749 if ( (matchLength > ZSTD_OPT_NUM)
750 | (ip+matchLength == iLimit) /* equal : no way to know if inf or sup */) {
751 break; /* drop, to guarantee consistency (miss a little bit of compression) */
752 }
753 }
754
755 if (dictMatchIndex <= dmsBtLow) { break; } /* beyond tree size, stop the search */
756 if (match[matchLength] < ip[matchLength]) {
757 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
758 dictMatchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
759 } else {
760 /* match is larger than current */
761 commonLengthLarger = matchLength;
762 dictMatchIndex = nextPtr[0];
763 }
764 }
765 }
766
767 assert(matchEndIdx > current+8);
768 ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */
769 return mnum;
770}
771
772
773FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches (
774 ZSTD_match_t* matches, /* store result (match found, increasing size) in this table */
775 ZSTD_matchState_t* ms,
776 U32* nextToUpdate3,
777 const BYTE* ip, const BYTE* const iHighLimit, const ZSTD_dictMode_e dictMode,
778 const U32 rep[ZSTD_REP_NUM],
779 U32 const ll0,
780 U32 const lengthToBeat)
781{
782 const ZSTD_compressionParameters* const cParams = &ms->cParams;
783 U32 const matchLengthSearch = cParams->minMatch;
784 DEBUGLOG(8, "ZSTD_BtGetAllMatches");
785 if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */
786 ZSTD_updateTree_internal(ms, ip, iHighLimit, matchLengthSearch, dictMode);
787 switch(matchLengthSearch)
788 {
789 case 3 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 3);
790 default :
791 case 4 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 4);
792 case 5 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 5);
793 case 7 :
794 case 6 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 6);
795 }
796}
797
798
799/*-*******************************
800* Optimal parser
801*********************************/
802typedef struct repcodes_s {
803 U32 rep[3];
804} repcodes_t;
805
806static repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0)
807{
808 repcodes_t newReps;
809 if (offset >= ZSTD_REP_NUM) { /* full offset */
810 newReps.rep[2] = rep[1];
811 newReps.rep[1] = rep[0];
812 newReps.rep[0] = offset - ZSTD_REP_MOVE;
813 } else { /* repcode */
814 U32 const repCode = offset + ll0;
815 if (repCode > 0) { /* note : if repCode==0, no change */
816 U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
817 newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
818 newReps.rep[1] = rep[0];
819 newReps.rep[0] = currentOffset;
820 } else { /* repCode == 0 */
821 memcpy(&newReps, rep, sizeof(newReps));
822 }
823 }
824 return newReps;
825}
826
827
828static U32 ZSTD_totalLen(ZSTD_optimal_t sol)
829{
830 return sol.litlen + sol.mlen;
831}
832
833#if 0 /* debug */
834
835static void
836listStats(const U32* table, int lastEltID)
837{
838 int const nbElts = lastEltID + 1;
839 int enb;
840 for (enb=0; enb < nbElts; enb++) {
841 (void)table;
842 //RAWLOG(2, "%3i:%3i, ", enb, table[enb]);
843 RAWLOG(2, "%4i,", table[enb]);
844 }
845 RAWLOG(2, " \n");
846}
847
848#endif
849
850FORCE_INLINE_TEMPLATE size_t
851ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
852 seqStore_t* seqStore,
853 U32 rep[ZSTD_REP_NUM],
854 const void* src, size_t srcSize,
855 const int optLevel,
856 const ZSTD_dictMode_e dictMode)
857{
858 optState_t* const optStatePtr = &ms->opt;
859 const BYTE* const istart = (const BYTE*)src;
860 const BYTE* ip = istart;
861 const BYTE* anchor = istart;
862 const BYTE* const iend = istart + srcSize;
863 const BYTE* const ilimit = iend - 8;
864 const BYTE* const base = ms->window.base;
865 const BYTE* const prefixStart = base + ms->window.dictLimit;
866 const ZSTD_compressionParameters* const cParams = &ms->cParams;
867
868 U32 const sufficient_len = MIN(cParams->targetLength, ZSTD_OPT_NUM -1);
869 U32 const minMatch = (cParams->minMatch == 3) ? 3 : 4;
870 U32 nextToUpdate3 = ms->nextToUpdate;
871
872 ZSTD_optimal_t* const opt = optStatePtr->priceTable;
873 ZSTD_match_t* const matches = optStatePtr->matchTable;
874 ZSTD_optimal_t lastSequence;
875
876 /* init */
877 DEBUGLOG(5, "ZSTD_compressBlock_opt_generic: current=%u, prefix=%u, nextToUpdate=%u",
878 (U32)(ip - base), ms->window.dictLimit, ms->nextToUpdate);
879 assert(optLevel <= 2);
880 ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize, optLevel);
881 ip += (ip==prefixStart);
882
883 /* Match Loop */
884 while (ip < ilimit) {
885 U32 cur, last_pos = 0;
886
887 /* find first match */
888 { U32 const litlen = (U32)(ip - anchor);
889 U32 const ll0 = !litlen;
890 U32 const nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, ip, iend, dictMode, rep, ll0, minMatch);
891 if (!nbMatches) { ip++; continue; }
892
893 /* initialize opt[0] */
894 { U32 i ; for (i=0; i<ZSTD_REP_NUM; i++) opt[0].rep[i] = rep[i]; }
895 opt[0].mlen = 0; /* means is_a_literal */
896 opt[0].litlen = litlen;
897 opt[0].price = ZSTD_literalsContribution(anchor, litlen, optStatePtr, optLevel);
898
899 /* large match -> immediate encoding */
900 { U32 const maxML = matches[nbMatches-1].len;
901 U32 const maxOffset = matches[nbMatches-1].off;
902 DEBUGLOG(6, "found %u matches of maxLength=%u and maxOffCode=%u at cPos=%u => start new series",
903 nbMatches, maxML, maxOffset, (U32)(ip-prefixStart));
904
905 if (maxML > sufficient_len) {
906 lastSequence.litlen = litlen;
907 lastSequence.mlen = maxML;
908 lastSequence.off = maxOffset;
909 DEBUGLOG(6, "large match (%u>%u), immediate encoding",
910 maxML, sufficient_len);
911 cur = 0;
912 last_pos = ZSTD_totalLen(lastSequence);
913 goto _shortestPath;
914 } }
915
916 /* set prices for first matches starting position == 0 */
917 { U32 const literalsPrice = opt[0].price + ZSTD_litLengthPrice(0, optStatePtr, optLevel);
918 U32 pos;
919 U32 matchNb;
920 for (pos = 1; pos < minMatch; pos++) {
921 opt[pos].price = ZSTD_MAX_PRICE; /* mlen, litlen and price will be fixed during forward scanning */
922 }
923 for (matchNb = 0; matchNb < nbMatches; matchNb++) {
924 U32 const offset = matches[matchNb].off;
925 U32 const end = matches[matchNb].len;
926 repcodes_t const repHistory = ZSTD_updateRep(rep, offset, ll0);
927 for ( ; pos <= end ; pos++ ) {
928 U32 const matchPrice = ZSTD_getMatchPrice(offset, pos, optStatePtr, optLevel);
929 U32 const sequencePrice = literalsPrice + matchPrice;
930 DEBUGLOG(7, "rPos:%u => set initial price : %.2f",
931 pos, ZSTD_fCost(sequencePrice));
932 opt[pos].mlen = pos;
933 opt[pos].off = offset;
934 opt[pos].litlen = litlen;
935 opt[pos].price = sequencePrice;
936 ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory));
937 memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
938 } }
939 last_pos = pos-1;
940 }
941 }
942
943 /* check further positions */
944 for (cur = 1; cur <= last_pos; cur++) {
945 const BYTE* const inr = ip + cur;
946 assert(cur < ZSTD_OPT_NUM);
947 DEBUGLOG(7, "cPos:%zi==rPos:%u", inr-istart, cur)
948
949 /* Fix current position with one literal if cheaper */
950 { U32 const litlen = (opt[cur-1].mlen == 0) ? opt[cur-1].litlen + 1 : 1;
951 int const price = opt[cur-1].price
952 + ZSTD_rawLiteralsCost(ip+cur-1, 1, optStatePtr, optLevel)
953 + ZSTD_litLengthPrice(litlen, optStatePtr, optLevel)
954 - ZSTD_litLengthPrice(litlen-1, optStatePtr, optLevel);
955 assert(price < 1000000000); /* overflow check */
956 if (price <= opt[cur].price) {
957 DEBUGLOG(7, "cPos:%zi==rPos:%u : better price (%.2f<=%.2f) using literal (ll==%u) (hist:%u,%u,%u)",
958 inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price), litlen,
959 opt[cur-1].rep[0], opt[cur-1].rep[1], opt[cur-1].rep[2]);
960 opt[cur].mlen = 0;
961 opt[cur].off = 0;
962 opt[cur].litlen = litlen;
963 opt[cur].price = price;
964 memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep));
965 } else {
966 DEBUGLOG(7, "cPos:%zi==rPos:%u : literal would cost more (%.2f>%.2f) (hist:%u,%u,%u)",
967 inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price),
968 opt[cur].rep[0], opt[cur].rep[1], opt[cur].rep[2]);
969 }
970 }
971
972 /* last match must start at a minimum distance of 8 from oend */
973 if (inr > ilimit) continue;
974
975 if (cur == last_pos) break;
976
977 if ( (optLevel==0) /*static_test*/
978 && (opt[cur+1].price <= opt[cur].price + (BITCOST_MULTIPLIER/2)) ) {
979 DEBUGLOG(7, "move to next rPos:%u : price is <=", cur+1);
980 continue; /* skip unpromising positions; about ~+6% speed, -0.01 ratio */
981 }
982
983 { U32 const ll0 = (opt[cur].mlen != 0);
984 U32 const litlen = (opt[cur].mlen == 0) ? opt[cur].litlen : 0;
985 U32 const previousPrice = opt[cur].price;
986 U32 const basePrice = previousPrice + ZSTD_litLengthPrice(0, optStatePtr, optLevel);
987 U32 const nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, inr, iend, dictMode, opt[cur].rep, ll0, minMatch);
988 U32 matchNb;
989 if (!nbMatches) {
990 DEBUGLOG(7, "rPos:%u : no match found", cur);
991 continue;
992 }
993
994 { U32 const maxML = matches[nbMatches-1].len;
995 DEBUGLOG(7, "cPos:%zi==rPos:%u, found %u matches, of maxLength=%u",
996 inr-istart, cur, nbMatches, maxML);
997
998 if ( (maxML > sufficient_len)
999 || (cur + maxML >= ZSTD_OPT_NUM) ) {
1000 lastSequence.mlen = maxML;
1001 lastSequence.off = matches[nbMatches-1].off;
1002 lastSequence.litlen = litlen;
1003 cur -= (opt[cur].mlen==0) ? opt[cur].litlen : 0; /* last sequence is actually only literals, fix cur to last match - note : may underflow, in which case, it's first sequence, and it's okay */
1004 last_pos = cur + ZSTD_totalLen(lastSequence);
1005 if (cur > ZSTD_OPT_NUM) cur = 0; /* underflow => first match */
1006 goto _shortestPath;
1007 } }
1008
1009 /* set prices using matches found at position == cur */
1010 for (matchNb = 0; matchNb < nbMatches; matchNb++) {
1011 U32 const offset = matches[matchNb].off;
1012 repcodes_t const repHistory = ZSTD_updateRep(opt[cur].rep, offset, ll0);
1013 U32 const lastML = matches[matchNb].len;
1014 U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
1015 U32 mlen;
1016
1017 DEBUGLOG(7, "testing match %u => offCode=%4u, mlen=%2u, llen=%2u",
1018 matchNb, matches[matchNb].off, lastML, litlen);
1019
1020 for (mlen = lastML; mlen >= startML; mlen--) { /* scan downward */
1021 U32 const pos = cur + mlen;
1022 int const price = basePrice + ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel);
1023
1024 if ((pos > last_pos) || (price < opt[pos].price)) {
1025 DEBUGLOG(7, "rPos:%u (ml=%2u) => new better price (%.2f<%.2f)",
1026 pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price));
1027 while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } /* fill empty positions */
1028 opt[pos].mlen = mlen;
1029 opt[pos].off = offset;
1030 opt[pos].litlen = litlen;
1031 opt[pos].price = price;
1032 ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory));
1033 memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
1034 } else {
1035 DEBUGLOG(7, "rPos:%u (ml=%2u) => new price is worse (%.2f>=%.2f)",
1036 pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price));
1037 if (optLevel==0) break; /* early update abort; gets ~+10% speed for about -0.01 ratio loss */
1038 }
1039 } } }
1040 } /* for (cur = 1; cur <= last_pos; cur++) */
1041
1042 lastSequence = opt[last_pos];
1043 cur = last_pos > ZSTD_totalLen(lastSequence) ? last_pos - ZSTD_totalLen(lastSequence) : 0; /* single sequence, and it starts before `ip` */
1044 assert(cur < ZSTD_OPT_NUM); /* control overflow*/
1045
1046_shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */
1047 assert(opt[0].mlen == 0);
1048
1049 { U32 const storeEnd = cur + 1;
1050 U32 storeStart = storeEnd;
1051 U32 seqPos = cur;
1052
1053 DEBUGLOG(6, "start reverse traversal (last_pos:%u, cur:%u)",
1054 last_pos, cur); (void)last_pos;
1055 assert(storeEnd < ZSTD_OPT_NUM);
1056 DEBUGLOG(6, "last sequence copied into pos=%u (llen=%u,mlen=%u,ofc=%u)",
1057 storeEnd, lastSequence.litlen, lastSequence.mlen, lastSequence.off);
1058 opt[storeEnd] = lastSequence;
1059 while (seqPos > 0) {
1060 U32 const backDist = ZSTD_totalLen(opt[seqPos]);
1061 storeStart--;
1062 DEBUGLOG(6, "sequence from rPos=%u copied into pos=%u (llen=%u,mlen=%u,ofc=%u)",
1063 seqPos, storeStart, opt[seqPos].litlen, opt[seqPos].mlen, opt[seqPos].off);
1064 opt[storeStart] = opt[seqPos];
1065 seqPos = (seqPos > backDist) ? seqPos - backDist : 0;
1066 }
1067
1068 /* save sequences */
1069 DEBUGLOG(6, "sending selected sequences into seqStore")
1070 { U32 storePos;
1071 for (storePos=storeStart; storePos <= storeEnd; storePos++) {
1072 U32 const llen = opt[storePos].litlen;
1073 U32 const mlen = opt[storePos].mlen;
1074 U32 const offCode = opt[storePos].off;
1075 U32 const advance = llen + mlen;
1076 DEBUGLOG(6, "considering seq starting at %zi, llen=%u, mlen=%u",
1077 anchor - istart, (unsigned)llen, (unsigned)mlen);
1078
1079 if (mlen==0) { /* only literals => must be last "sequence", actually starting a new stream of sequences */
1080 assert(storePos == storeEnd); /* must be last sequence */
1081 ip = anchor + llen; /* last "sequence" is a bunch of literals => don't progress anchor */
1082 continue; /* will finish */
1083 }
1084
1085 /* repcodes update : like ZSTD_updateRep(), but update in place */
1086 if (offCode >= ZSTD_REP_NUM) { /* full offset */
1087 rep[2] = rep[1];
1088 rep[1] = rep[0];
1089 rep[0] = offCode - ZSTD_REP_MOVE;
1090 } else { /* repcode */
1091 U32 const repCode = offCode + (llen==0);
1092 if (repCode) { /* note : if repCode==0, no change */
1093 U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
1094 if (repCode >= 2) rep[2] = rep[1];
1095 rep[1] = rep[0];
1096 rep[0] = currentOffset;
1097 } }
1098
1099 assert(anchor + llen <= iend);
1100 ZSTD_updateStats(optStatePtr, llen, anchor, offCode, mlen);
1101 ZSTD_storeSeq(seqStore, llen, anchor, offCode, mlen-MINMATCH);
1102 anchor += advance;
1103 ip = anchor;
1104 } }
1105 ZSTD_setBasePrices(optStatePtr, optLevel);
1106 }
1107
1108 } /* while (ip < ilimit) */
1109
1110 /* Return the last literals size */
1111 return (size_t)(iend - anchor);
1112}
1113
1114
1115size_t ZSTD_compressBlock_btopt(
1116 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1117 const void* src, size_t srcSize)
1118{
1119 DEBUGLOG(5, "ZSTD_compressBlock_btopt");
1120 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /*optLevel*/, ZSTD_noDict);
1121}
1122
1123
1124/* used in 2-pass strategy */
1125static U32 ZSTD_upscaleStat(unsigned* table, U32 lastEltIndex, int bonus)
1126{
1127 U32 s, sum=0;
1128 assert(ZSTD_FREQ_DIV+bonus >= 0);
1129 for (s=0; s<lastEltIndex+1; s++) {
1130 table[s] <<= ZSTD_FREQ_DIV+bonus;
1131 table[s]--;
1132 sum += table[s];
1133 }
1134 return sum;
1135}
1136
1137/* used in 2-pass strategy */
1138MEM_STATIC void ZSTD_upscaleStats(optState_t* optPtr)
1139{
1140 if (ZSTD_compressedLiterals(optPtr))
1141 optPtr->litSum = ZSTD_upscaleStat(optPtr->litFreq, MaxLit, 0);
1142 optPtr->litLengthSum = ZSTD_upscaleStat(optPtr->litLengthFreq, MaxLL, 0);
1143 optPtr->matchLengthSum = ZSTD_upscaleStat(optPtr->matchLengthFreq, MaxML, 0);
1144 optPtr->offCodeSum = ZSTD_upscaleStat(optPtr->offCodeFreq, MaxOff, 0);
1145}
1146
1147/* ZSTD_initStats_ultra():
1148 * make a first compression pass, just to seed stats with more accurate starting values.
1149 * only works on first block, with no dictionary and no ldm.
1150 * this function cannot error, hence its contract must be respected.
1151 */
1152static void
1153ZSTD_initStats_ultra(ZSTD_matchState_t* ms,
1154 seqStore_t* seqStore,
1155 U32 rep[ZSTD_REP_NUM],
1156 const void* src, size_t srcSize)
1157{
1158 U32 tmpRep[ZSTD_REP_NUM]; /* updated rep codes will sink here */
1159 memcpy(tmpRep, rep, sizeof(tmpRep));
1160
1161 DEBUGLOG(4, "ZSTD_initStats_ultra (srcSize=%zu)", srcSize);
1162 assert(ms->opt.litLengthSum == 0); /* first block */
1163 assert(seqStore->sequences == seqStore->sequencesStart); /* no ldm */
1164 assert(ms->window.dictLimit == ms->window.lowLimit); /* no dictionary */
1165 assert(ms->window.dictLimit - ms->nextToUpdate <= 1); /* no prefix (note: intentional overflow, defined as 2-complement) */
1166
1167 ZSTD_compressBlock_opt_generic(ms, seqStore, tmpRep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict); /* generate stats into ms->opt*/
1168
1169 /* invalidate first scan from history */
1170 ZSTD_resetSeqStore(seqStore);
1171 ms->window.base -= srcSize;
1172 ms->window.dictLimit += (U32)srcSize;
1173 ms->window.lowLimit = ms->window.dictLimit;
1174 ms->nextToUpdate = ms->window.dictLimit;
1175
1176 /* re-inforce weight of collected statistics */
1177 ZSTD_upscaleStats(&ms->opt);
1178}
1179
1180size_t ZSTD_compressBlock_btultra(
1181 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1182 const void* src, size_t srcSize)
1183{
1184 DEBUGLOG(5, "ZSTD_compressBlock_btultra (srcSize=%zu)", srcSize);
1185 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict);
1186}
1187
1188size_t ZSTD_compressBlock_btultra2(
1189 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1190 const void* src, size_t srcSize)
1191{
1192 U32 const current = (U32)((const BYTE*)src - ms->window.base);
1193 DEBUGLOG(5, "ZSTD_compressBlock_btultra2 (srcSize=%zu)", srcSize);
1194
1195 /* 2-pass strategy:
1196 * this strategy makes a first pass over first block to collect statistics
1197 * and seed next round's statistics with it.
1198 * After 1st pass, function forgets everything, and starts a new block.
1199 * Consequently, this can only work if no data has been previously loaded in tables,
1200 * aka, no dictionary, no prefix, no ldm preprocessing.
1201 * The compression ratio gain is generally small (~0.5% on first block),
1202 * the cost is 2x cpu time on first block. */
1203 assert(srcSize <= ZSTD_BLOCKSIZE_MAX);
1204 if ( (ms->opt.litLengthSum==0) /* first block */
1205 && (seqStore->sequences == seqStore->sequencesStart) /* no ldm */
1206 && (ms->window.dictLimit == ms->window.lowLimit) /* no dictionary */
1207 && (current == ms->window.dictLimit) /* start of frame, nothing already loaded nor skipped */
1208 && (srcSize > ZSTD_PREDEF_THRESHOLD)
1209 ) {
1210 ZSTD_initStats_ultra(ms, seqStore, rep, src, srcSize);
1211 }
1212
1213 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict);
1214}
1215
1216size_t ZSTD_compressBlock_btopt_dictMatchState(
1217 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1218 const void* src, size_t srcSize)
1219{
1220 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /*optLevel*/, ZSTD_dictMatchState);
1221}
1222
1223size_t ZSTD_compressBlock_btultra_dictMatchState(
1224 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1225 const void* src, size_t srcSize)
1226{
1227 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_dictMatchState);
1228}
1229
1230size_t ZSTD_compressBlock_btopt_extDict(
1231 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1232 const void* src, size_t srcSize)
1233{
1234 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /*optLevel*/, ZSTD_extDict);
1235}
1236
1237size_t ZSTD_compressBlock_btultra_extDict(
1238 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1239 const void* src, size_t srcSize)
1240{
1241 return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_extDict);
1242}
1243
1244/* note : no btultra2 variant for extDict nor dictMatchState,
1245 * because btultra2 is not meant to work with dictionaries
1246 * and is only specific for the first block (no prefix) */