1 | /* |
2 | * Copyright (c) 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" /* ZSTD_hashPtr, ZSTD_count, ZSTD_storeSeq */ |
12 | #include "zstd_fast.h" |
13 | |
14 | |
15 | void ZSTD_fillHashTable(ZSTD_matchState_t* ms, |
16 | const void* const end, |
17 | ZSTD_dictTableLoadMethod_e dtlm) |
18 | { |
19 | const ZSTD_compressionParameters* const cParams = &ms->cParams; |
20 | U32* const hashTable = ms->hashTable; |
21 | U32 const hBits = cParams->hashLog; |
22 | U32 const mls = cParams->minMatch; |
23 | const BYTE* const base = ms->window.base; |
24 | const BYTE* ip = base + ms->nextToUpdate; |
25 | const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE; |
26 | const U32 fastHashFillStep = 3; |
27 | |
28 | /* Always insert every fastHashFillStep position into the hash table. |
29 | * Insert the other positions if their hash entry is empty. |
30 | */ |
31 | for ( ; ip + fastHashFillStep < iend + 2; ip += fastHashFillStep) { |
32 | U32 const curr = (U32)(ip - base); |
33 | size_t const hash0 = ZSTD_hashPtr(p: ip, hBits, mls); |
34 | hashTable[hash0] = curr; |
35 | if (dtlm == ZSTD_dtlm_fast) continue; |
36 | /* Only load extra positions for ZSTD_dtlm_full */ |
37 | { U32 p; |
38 | for (p = 1; p < fastHashFillStep; ++p) { |
39 | size_t const hash = ZSTD_hashPtr(p: ip + p, hBits, mls); |
40 | if (hashTable[hash] == 0) { /* not yet filled */ |
41 | hashTable[hash] = curr + p; |
42 | } } } } |
43 | } |
44 | |
45 | |
46 | /* |
47 | * If you squint hard enough (and ignore repcodes), the search operation at any |
48 | * given position is broken into 4 stages: |
49 | * |
50 | * 1. Hash (map position to hash value via input read) |
51 | * 2. Lookup (map hash val to index via hashtable read) |
52 | * 3. Load (map index to value at that position via input read) |
53 | * 4. Compare |
54 | * |
55 | * Each of these steps involves a memory read at an address which is computed |
56 | * from the previous step. This means these steps must be sequenced and their |
57 | * latencies are cumulative. |
58 | * |
59 | * Rather than do 1->2->3->4 sequentially for a single position before moving |
60 | * onto the next, this implementation interleaves these operations across the |
61 | * next few positions: |
62 | * |
63 | * R = Repcode Read & Compare |
64 | * H = Hash |
65 | * T = Table Lookup |
66 | * M = Match Read & Compare |
67 | * |
68 | * Pos | Time --> |
69 | * ----+------------------- |
70 | * N | ... M |
71 | * N+1 | ... TM |
72 | * N+2 | R H T M |
73 | * N+3 | H TM |
74 | * N+4 | R H T M |
75 | * N+5 | H ... |
76 | * N+6 | R ... |
77 | * |
78 | * This is very much analogous to the pipelining of execution in a CPU. And just |
79 | * like a CPU, we have to dump the pipeline when we find a match (i.e., take a |
80 | * branch). |
81 | * |
82 | * When this happens, we throw away our current state, and do the following prep |
83 | * to re-enter the loop: |
84 | * |
85 | * Pos | Time --> |
86 | * ----+------------------- |
87 | * N | H T |
88 | * N+1 | H |
89 | * |
90 | * This is also the work we do at the beginning to enter the loop initially. |
91 | */ |
92 | FORCE_INLINE_TEMPLATE size_t |
93 | ZSTD_compressBlock_fast_noDict_generic( |
94 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
95 | void const* src, size_t srcSize, |
96 | U32 const mls, U32 const hasStep) |
97 | { |
98 | const ZSTD_compressionParameters* const cParams = &ms->cParams; |
99 | U32* const hashTable = ms->hashTable; |
100 | U32 const hlog = cParams->hashLog; |
101 | /* support stepSize of 0 */ |
102 | size_t const stepSize = hasStep ? (cParams->targetLength + !(cParams->targetLength) + 1) : 2; |
103 | const BYTE* const base = ms->window.base; |
104 | const BYTE* const istart = (const BYTE*)src; |
105 | const U32 endIndex = (U32)((size_t)(istart - base) + srcSize); |
106 | const U32 prefixStartIndex = ZSTD_getLowestPrefixIndex(ms, curr: endIndex, windowLog: cParams->windowLog); |
107 | const BYTE* const prefixStart = base + prefixStartIndex; |
108 | const BYTE* const iend = istart + srcSize; |
109 | const BYTE* const ilimit = iend - HASH_READ_SIZE; |
110 | |
111 | const BYTE* anchor = istart; |
112 | const BYTE* ip0 = istart; |
113 | const BYTE* ip1; |
114 | const BYTE* ip2; |
115 | const BYTE* ip3; |
116 | U32 current0; |
117 | |
118 | U32 rep_offset1 = rep[0]; |
119 | U32 rep_offset2 = rep[1]; |
120 | U32 offsetSaved = 0; |
121 | |
122 | size_t hash0; /* hash for ip0 */ |
123 | size_t hash1; /* hash for ip1 */ |
124 | U32 idx; /* match idx for ip0 */ |
125 | U32 mval; /* src value at match idx */ |
126 | |
127 | U32 offcode; |
128 | const BYTE* match0; |
129 | size_t mLength; |
130 | |
131 | /* ip0 and ip1 are always adjacent. The targetLength skipping and |
132 | * uncompressibility acceleration is applied to every other position, |
133 | * matching the behavior of #1562. step therefore represents the gap |
134 | * between pairs of positions, from ip0 to ip2 or ip1 to ip3. */ |
135 | size_t step; |
136 | const BYTE* nextStep; |
137 | const size_t kStepIncr = (1 << (kSearchStrength - 1)); |
138 | |
139 | DEBUGLOG(5, "ZSTD_compressBlock_fast_generic" ); |
140 | ip0 += (ip0 == prefixStart); |
141 | { U32 const curr = (U32)(ip0 - base); |
142 | U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, windowLog: cParams->windowLog); |
143 | U32 const maxRep = curr - windowLow; |
144 | if (rep_offset2 > maxRep) offsetSaved = rep_offset2, rep_offset2 = 0; |
145 | if (rep_offset1 > maxRep) offsetSaved = rep_offset1, rep_offset1 = 0; |
146 | } |
147 | |
148 | /* start each op */ |
149 | _start: /* Requires: ip0 */ |
150 | |
151 | step = stepSize; |
152 | nextStep = ip0 + kStepIncr; |
153 | |
154 | /* calculate positions, ip0 - anchor == 0, so we skip step calc */ |
155 | ip1 = ip0 + 1; |
156 | ip2 = ip0 + step; |
157 | ip3 = ip2 + 1; |
158 | |
159 | if (ip3 >= ilimit) { |
160 | goto _cleanup; |
161 | } |
162 | |
163 | hash0 = ZSTD_hashPtr(p: ip0, hBits: hlog, mls); |
164 | hash1 = ZSTD_hashPtr(p: ip1, hBits: hlog, mls); |
165 | |
166 | idx = hashTable[hash0]; |
167 | |
168 | do { |
169 | /* load repcode match for ip[2]*/ |
170 | const U32 rval = MEM_read32(memPtr: ip2 - rep_offset1); |
171 | |
172 | /* write back hash table entry */ |
173 | current0 = (U32)(ip0 - base); |
174 | hashTable[hash0] = current0; |
175 | |
176 | /* check repcode at ip[2] */ |
177 | if ((MEM_read32(memPtr: ip2) == rval) & (rep_offset1 > 0)) { |
178 | ip0 = ip2; |
179 | match0 = ip0 - rep_offset1; |
180 | mLength = ip0[-1] == match0[-1]; |
181 | ip0 -= mLength; |
182 | match0 -= mLength; |
183 | offcode = STORE_REPCODE_1; |
184 | mLength += 4; |
185 | goto _match; |
186 | } |
187 | |
188 | /* load match for ip[0] */ |
189 | if (idx >= prefixStartIndex) { |
190 | mval = MEM_read32(memPtr: base + idx); |
191 | } else { |
192 | mval = MEM_read32(memPtr: ip0) ^ 1; /* guaranteed to not match. */ |
193 | } |
194 | |
195 | /* check match at ip[0] */ |
196 | if (MEM_read32(memPtr: ip0) == mval) { |
197 | /* found a match! */ |
198 | goto _offset; |
199 | } |
200 | |
201 | /* lookup ip[1] */ |
202 | idx = hashTable[hash1]; |
203 | |
204 | /* hash ip[2] */ |
205 | hash0 = hash1; |
206 | hash1 = ZSTD_hashPtr(p: ip2, hBits: hlog, mls); |
207 | |
208 | /* advance to next positions */ |
209 | ip0 = ip1; |
210 | ip1 = ip2; |
211 | ip2 = ip3; |
212 | |
213 | /* write back hash table entry */ |
214 | current0 = (U32)(ip0 - base); |
215 | hashTable[hash0] = current0; |
216 | |
217 | /* load match for ip[0] */ |
218 | if (idx >= prefixStartIndex) { |
219 | mval = MEM_read32(memPtr: base + idx); |
220 | } else { |
221 | mval = MEM_read32(memPtr: ip0) ^ 1; /* guaranteed to not match. */ |
222 | } |
223 | |
224 | /* check match at ip[0] */ |
225 | if (MEM_read32(memPtr: ip0) == mval) { |
226 | /* found a match! */ |
227 | goto _offset; |
228 | } |
229 | |
230 | /* lookup ip[1] */ |
231 | idx = hashTable[hash1]; |
232 | |
233 | /* hash ip[2] */ |
234 | hash0 = hash1; |
235 | hash1 = ZSTD_hashPtr(p: ip2, hBits: hlog, mls); |
236 | |
237 | /* advance to next positions */ |
238 | ip0 = ip1; |
239 | ip1 = ip2; |
240 | ip2 = ip0 + step; |
241 | ip3 = ip1 + step; |
242 | |
243 | /* calculate step */ |
244 | if (ip2 >= nextStep) { |
245 | step++; |
246 | PREFETCH_L1(ip1 + 64); |
247 | PREFETCH_L1(ip1 + 128); |
248 | nextStep += kStepIncr; |
249 | } |
250 | } while (ip3 < ilimit); |
251 | |
252 | _cleanup: |
253 | /* Note that there are probably still a couple positions we could search. |
254 | * However, it seems to be a meaningful performance hit to try to search |
255 | * them. So let's not. */ |
256 | |
257 | /* save reps for next block */ |
258 | rep[0] = rep_offset1 ? rep_offset1 : offsetSaved; |
259 | rep[1] = rep_offset2 ? rep_offset2 : offsetSaved; |
260 | |
261 | /* Return the last literals size */ |
262 | return (size_t)(iend - anchor); |
263 | |
264 | _offset: /* Requires: ip0, idx */ |
265 | |
266 | /* Compute the offset code. */ |
267 | match0 = base + idx; |
268 | rep_offset2 = rep_offset1; |
269 | rep_offset1 = (U32)(ip0-match0); |
270 | offcode = STORE_OFFSET(rep_offset1); |
271 | mLength = 4; |
272 | |
273 | /* Count the backwards match length. */ |
274 | while (((ip0>anchor) & (match0>prefixStart)) && (ip0[-1] == match0[-1])) { |
275 | ip0--; |
276 | match0--; |
277 | mLength++; |
278 | } |
279 | |
280 | _match: /* Requires: ip0, match0, offcode */ |
281 | |
282 | /* Count the forward length. */ |
283 | mLength += ZSTD_count(pIn: ip0 + mLength, pMatch: match0 + mLength, pInLimit: iend); |
284 | |
285 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: (size_t)(ip0 - anchor), literals: anchor, litLimit: iend, offBase_minus1: offcode, matchLength: mLength); |
286 | |
287 | ip0 += mLength; |
288 | anchor = ip0; |
289 | |
290 | /* write next hash table entry */ |
291 | if (ip1 < ip0) { |
292 | hashTable[hash1] = (U32)(ip1 - base); |
293 | } |
294 | |
295 | /* Fill table and check for immediate repcode. */ |
296 | if (ip0 <= ilimit) { |
297 | /* Fill Table */ |
298 | assert(base+current0+2 > istart); /* check base overflow */ |
299 | hashTable[ZSTD_hashPtr(p: base+current0+2, hBits: hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */ |
300 | hashTable[ZSTD_hashPtr(p: ip0-2, hBits: hlog, mls)] = (U32)(ip0-2-base); |
301 | |
302 | if (rep_offset2 > 0) { /* rep_offset2==0 means rep_offset2 is invalidated */ |
303 | while ( (ip0 <= ilimit) && (MEM_read32(memPtr: ip0) == MEM_read32(memPtr: ip0 - rep_offset2)) ) { |
304 | /* store sequence */ |
305 | size_t const rLength = ZSTD_count(pIn: ip0+4, pMatch: ip0+4-rep_offset2, pInLimit: iend) + 4; |
306 | { U32 const tmpOff = rep_offset2; rep_offset2 = rep_offset1; rep_offset1 = tmpOff; } /* swap rep_offset2 <=> rep_offset1 */ |
307 | hashTable[ZSTD_hashPtr(p: ip0, hBits: hlog, mls)] = (U32)(ip0-base); |
308 | ip0 += rLength; |
309 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: 0 /*litLen*/, literals: anchor, litLimit: iend, STORE_REPCODE_1, matchLength: rLength); |
310 | anchor = ip0; |
311 | continue; /* faster when present (confirmed on gcc-8) ... (?) */ |
312 | } } } |
313 | |
314 | goto _start; |
315 | } |
316 | |
317 | #define ZSTD_GEN_FAST_FN(dictMode, mls, step) \ |
318 | static size_t ZSTD_compressBlock_fast_##dictMode##_##mls##_##step( \ |
319 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], \ |
320 | void const* src, size_t srcSize) \ |
321 | { \ |
322 | return ZSTD_compressBlock_fast_##dictMode##_generic(ms, seqStore, rep, src, srcSize, mls, step); \ |
323 | } |
324 | |
325 | ZSTD_GEN_FAST_FN(noDict, 4, 1) |
326 | ZSTD_GEN_FAST_FN(noDict, 5, 1) |
327 | ZSTD_GEN_FAST_FN(noDict, 6, 1) |
328 | ZSTD_GEN_FAST_FN(noDict, 7, 1) |
329 | |
330 | ZSTD_GEN_FAST_FN(noDict, 4, 0) |
331 | ZSTD_GEN_FAST_FN(noDict, 5, 0) |
332 | ZSTD_GEN_FAST_FN(noDict, 6, 0) |
333 | ZSTD_GEN_FAST_FN(noDict, 7, 0) |
334 | |
335 | size_t ZSTD_compressBlock_fast( |
336 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
337 | void const* src, size_t srcSize) |
338 | { |
339 | U32 const mls = ms->cParams.minMatch; |
340 | assert(ms->dictMatchState == NULL); |
341 | if (ms->cParams.targetLength > 1) { |
342 | switch(mls) |
343 | { |
344 | default: /* includes case 3 */ |
345 | case 4 : |
346 | return ZSTD_compressBlock_fast_noDict_4_1(ms, seqStore, rep, src, srcSize); |
347 | case 5 : |
348 | return ZSTD_compressBlock_fast_noDict_5_1(ms, seqStore, rep, src, srcSize); |
349 | case 6 : |
350 | return ZSTD_compressBlock_fast_noDict_6_1(ms, seqStore, rep, src, srcSize); |
351 | case 7 : |
352 | return ZSTD_compressBlock_fast_noDict_7_1(ms, seqStore, rep, src, srcSize); |
353 | } |
354 | } else { |
355 | switch(mls) |
356 | { |
357 | default: /* includes case 3 */ |
358 | case 4 : |
359 | return ZSTD_compressBlock_fast_noDict_4_0(ms, seqStore, rep, src, srcSize); |
360 | case 5 : |
361 | return ZSTD_compressBlock_fast_noDict_5_0(ms, seqStore, rep, src, srcSize); |
362 | case 6 : |
363 | return ZSTD_compressBlock_fast_noDict_6_0(ms, seqStore, rep, src, srcSize); |
364 | case 7 : |
365 | return ZSTD_compressBlock_fast_noDict_7_0(ms, seqStore, rep, src, srcSize); |
366 | } |
367 | |
368 | } |
369 | } |
370 | |
371 | FORCE_INLINE_TEMPLATE |
372 | size_t ZSTD_compressBlock_fast_dictMatchState_generic( |
373 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
374 | void const* src, size_t srcSize, U32 const mls, U32 const hasStep) |
375 | { |
376 | const ZSTD_compressionParameters* const cParams = &ms->cParams; |
377 | U32* const hashTable = ms->hashTable; |
378 | U32 const hlog = cParams->hashLog; |
379 | /* support stepSize of 0 */ |
380 | U32 const stepSize = cParams->targetLength + !(cParams->targetLength); |
381 | const BYTE* const base = ms->window.base; |
382 | const BYTE* const istart = (const BYTE*)src; |
383 | const BYTE* ip = istart; |
384 | const BYTE* anchor = istart; |
385 | const U32 prefixStartIndex = ms->window.dictLimit; |
386 | const BYTE* const prefixStart = base + prefixStartIndex; |
387 | const BYTE* const iend = istart + srcSize; |
388 | const BYTE* const ilimit = iend - HASH_READ_SIZE; |
389 | U32 offset_1=rep[0], offset_2=rep[1]; |
390 | U32 offsetSaved = 0; |
391 | |
392 | const ZSTD_matchState_t* const dms = ms->dictMatchState; |
393 | const ZSTD_compressionParameters* const dictCParams = &dms->cParams ; |
394 | const U32* const dictHashTable = dms->hashTable; |
395 | const U32 dictStartIndex = dms->window.dictLimit; |
396 | const BYTE* const dictBase = dms->window.base; |
397 | const BYTE* const dictStart = dictBase + dictStartIndex; |
398 | const BYTE* const dictEnd = dms->window.nextSrc; |
399 | const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase); |
400 | const U32 dictAndPrefixLength = (U32)(ip - prefixStart + dictEnd - dictStart); |
401 | const U32 dictHLog = dictCParams->hashLog; |
402 | |
403 | /* if a dictionary is still attached, it necessarily means that |
404 | * it is within window size. So we just check it. */ |
405 | const U32 maxDistance = 1U << cParams->windowLog; |
406 | const U32 endIndex = (U32)((size_t)(ip - base) + srcSize); |
407 | assert(endIndex - prefixStartIndex <= maxDistance); |
408 | (void)maxDistance; (void)endIndex; /* these variables are not used when assert() is disabled */ |
409 | |
410 | (void)hasStep; /* not currently specialized on whether it's accelerated */ |
411 | |
412 | /* ensure there will be no underflow |
413 | * when translating a dict index into a local index */ |
414 | assert(prefixStartIndex >= (U32)(dictEnd - dictBase)); |
415 | |
416 | /* init */ |
417 | DEBUGLOG(5, "ZSTD_compressBlock_fast_dictMatchState_generic" ); |
418 | ip += (dictAndPrefixLength == 0); |
419 | /* dictMatchState repCode checks don't currently handle repCode == 0 |
420 | * disabling. */ |
421 | assert(offset_1 <= dictAndPrefixLength); |
422 | assert(offset_2 <= dictAndPrefixLength); |
423 | |
424 | /* Main Search Loop */ |
425 | while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ |
426 | size_t mLength; |
427 | size_t const h = ZSTD_hashPtr(p: ip, hBits: hlog, mls); |
428 | U32 const curr = (U32)(ip-base); |
429 | U32 const matchIndex = hashTable[h]; |
430 | const BYTE* match = base + matchIndex; |
431 | const U32 repIndex = curr + 1 - offset_1; |
432 | const BYTE* repMatch = (repIndex < prefixStartIndex) ? |
433 | dictBase + (repIndex - dictIndexDelta) : |
434 | base + repIndex; |
435 | hashTable[h] = curr; /* update hash table */ |
436 | |
437 | if ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex isn't overlapping dict + prefix */ |
438 | && (MEM_read32(memPtr: repMatch) == MEM_read32(memPtr: ip+1)) ) { |
439 | const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend; |
440 | mLength = ZSTD_count_2segments(ip: ip+1+4, match: repMatch+4, iEnd: iend, mEnd: repMatchEnd, iStart: prefixStart) + 4; |
441 | ip++; |
442 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: (size_t)(ip-anchor), literals: anchor, litLimit: iend, STORE_REPCODE_1, matchLength: mLength); |
443 | } else if ( (matchIndex <= prefixStartIndex) ) { |
444 | size_t const dictHash = ZSTD_hashPtr(p: ip, hBits: dictHLog, mls); |
445 | U32 const dictMatchIndex = dictHashTable[dictHash]; |
446 | const BYTE* dictMatch = dictBase + dictMatchIndex; |
447 | if (dictMatchIndex <= dictStartIndex || |
448 | MEM_read32(memPtr: dictMatch) != MEM_read32(memPtr: ip)) { |
449 | assert(stepSize >= 1); |
450 | ip += ((ip-anchor) >> kSearchStrength) + stepSize; |
451 | continue; |
452 | } else { |
453 | /* found a dict match */ |
454 | U32 const offset = (U32)(curr-dictMatchIndex-dictIndexDelta); |
455 | mLength = ZSTD_count_2segments(ip: ip+4, match: dictMatch+4, iEnd: iend, mEnd: dictEnd, iStart: prefixStart) + 4; |
456 | while (((ip>anchor) & (dictMatch>dictStart)) |
457 | && (ip[-1] == dictMatch[-1])) { |
458 | ip--; dictMatch--; mLength++; |
459 | } /* catch up */ |
460 | offset_2 = offset_1; |
461 | offset_1 = offset; |
462 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: (size_t)(ip-anchor), literals: anchor, litLimit: iend, STORE_OFFSET(offset), matchLength: mLength); |
463 | } |
464 | } else if (MEM_read32(memPtr: match) != MEM_read32(memPtr: ip)) { |
465 | /* it's not a match, and we're not going to check the dictionary */ |
466 | assert(stepSize >= 1); |
467 | ip += ((ip-anchor) >> kSearchStrength) + stepSize; |
468 | continue; |
469 | } else { |
470 | /* found a regular match */ |
471 | U32 const offset = (U32)(ip-match); |
472 | mLength = ZSTD_count(pIn: ip+4, pMatch: match+4, pInLimit: iend) + 4; |
473 | while (((ip>anchor) & (match>prefixStart)) |
474 | && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ |
475 | offset_2 = offset_1; |
476 | offset_1 = offset; |
477 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: (size_t)(ip-anchor), literals: anchor, litLimit: iend, STORE_OFFSET(offset), matchLength: mLength); |
478 | } |
479 | |
480 | /* match found */ |
481 | ip += mLength; |
482 | anchor = ip; |
483 | |
484 | if (ip <= ilimit) { |
485 | /* Fill Table */ |
486 | assert(base+curr+2 > istart); /* check base overflow */ |
487 | hashTable[ZSTD_hashPtr(p: base+curr+2, hBits: hlog, mls)] = curr+2; /* here because curr+2 could be > iend-8 */ |
488 | hashTable[ZSTD_hashPtr(p: ip-2, hBits: hlog, mls)] = (U32)(ip-2-base); |
489 | |
490 | /* check immediate repcode */ |
491 | while (ip <= ilimit) { |
492 | U32 const current2 = (U32)(ip-base); |
493 | U32 const repIndex2 = current2 - offset_2; |
494 | const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? |
495 | dictBase - dictIndexDelta + repIndex2 : |
496 | base + repIndex2; |
497 | if ( ((U32)((prefixStartIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */) |
498 | && (MEM_read32(memPtr: repMatch2) == MEM_read32(memPtr: ip)) ) { |
499 | const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend; |
500 | size_t const repLength2 = ZSTD_count_2segments(ip: ip+4, match: repMatch2+4, iEnd: iend, mEnd: repEnd2, iStart: prefixStart) + 4; |
501 | U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ |
502 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: 0, literals: anchor, litLimit: iend, STORE_REPCODE_1, matchLength: repLength2); |
503 | hashTable[ZSTD_hashPtr(p: ip, hBits: hlog, mls)] = current2; |
504 | ip += repLength2; |
505 | anchor = ip; |
506 | continue; |
507 | } |
508 | break; |
509 | } |
510 | } |
511 | } |
512 | |
513 | /* save reps for next block */ |
514 | rep[0] = offset_1 ? offset_1 : offsetSaved; |
515 | rep[1] = offset_2 ? offset_2 : offsetSaved; |
516 | |
517 | /* Return the last literals size */ |
518 | return (size_t)(iend - anchor); |
519 | } |
520 | |
521 | |
522 | ZSTD_GEN_FAST_FN(dictMatchState, 4, 0) |
523 | ZSTD_GEN_FAST_FN(dictMatchState, 5, 0) |
524 | ZSTD_GEN_FAST_FN(dictMatchState, 6, 0) |
525 | ZSTD_GEN_FAST_FN(dictMatchState, 7, 0) |
526 | |
527 | size_t ZSTD_compressBlock_fast_dictMatchState( |
528 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
529 | void const* src, size_t srcSize) |
530 | { |
531 | U32 const mls = ms->cParams.minMatch; |
532 | assert(ms->dictMatchState != NULL); |
533 | switch(mls) |
534 | { |
535 | default: /* includes case 3 */ |
536 | case 4 : |
537 | return ZSTD_compressBlock_fast_dictMatchState_4_0(ms, seqStore, rep, src, srcSize); |
538 | case 5 : |
539 | return ZSTD_compressBlock_fast_dictMatchState_5_0(ms, seqStore, rep, src, srcSize); |
540 | case 6 : |
541 | return ZSTD_compressBlock_fast_dictMatchState_6_0(ms, seqStore, rep, src, srcSize); |
542 | case 7 : |
543 | return ZSTD_compressBlock_fast_dictMatchState_7_0(ms, seqStore, rep, src, srcSize); |
544 | } |
545 | } |
546 | |
547 | |
548 | static size_t ZSTD_compressBlock_fast_extDict_generic( |
549 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
550 | void const* src, size_t srcSize, U32 const mls, U32 const hasStep) |
551 | { |
552 | const ZSTD_compressionParameters* const cParams = &ms->cParams; |
553 | U32* const hashTable = ms->hashTable; |
554 | U32 const hlog = cParams->hashLog; |
555 | /* support stepSize of 0 */ |
556 | U32 const stepSize = cParams->targetLength + !(cParams->targetLength); |
557 | const BYTE* const base = ms->window.base; |
558 | const BYTE* const dictBase = ms->window.dictBase; |
559 | const BYTE* const istart = (const BYTE*)src; |
560 | const BYTE* ip = istart; |
561 | const BYTE* anchor = istart; |
562 | const U32 endIndex = (U32)((size_t)(istart - base) + srcSize); |
563 | const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, curr: endIndex, windowLog: cParams->windowLog); |
564 | const U32 dictStartIndex = lowLimit; |
565 | const BYTE* const dictStart = dictBase + dictStartIndex; |
566 | const U32 dictLimit = ms->window.dictLimit; |
567 | const U32 prefixStartIndex = dictLimit < lowLimit ? lowLimit : dictLimit; |
568 | const BYTE* const prefixStart = base + prefixStartIndex; |
569 | const BYTE* const dictEnd = dictBase + prefixStartIndex; |
570 | const BYTE* const iend = istart + srcSize; |
571 | const BYTE* const ilimit = iend - 8; |
572 | U32 offset_1=rep[0], offset_2=rep[1]; |
573 | |
574 | (void)hasStep; /* not currently specialized on whether it's accelerated */ |
575 | |
576 | DEBUGLOG(5, "ZSTD_compressBlock_fast_extDict_generic (offset_1=%u)" , offset_1); |
577 | |
578 | /* switch to "regular" variant if extDict is invalidated due to maxDistance */ |
579 | if (prefixStartIndex == dictStartIndex) |
580 | return ZSTD_compressBlock_fast(ms, seqStore, rep, src, srcSize); |
581 | |
582 | /* Search Loop */ |
583 | while (ip < ilimit) { /* < instead of <=, because (ip+1) */ |
584 | const size_t h = ZSTD_hashPtr(p: ip, hBits: hlog, mls); |
585 | const U32 matchIndex = hashTable[h]; |
586 | const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base; |
587 | const BYTE* match = matchBase + matchIndex; |
588 | const U32 curr = (U32)(ip-base); |
589 | const U32 repIndex = curr + 1 - offset_1; |
590 | const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base; |
591 | const BYTE* const repMatch = repBase + repIndex; |
592 | hashTable[h] = curr; /* update hash table */ |
593 | DEBUGLOG(7, "offset_1 = %u , curr = %u" , offset_1, curr); |
594 | |
595 | if ( ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ |
596 | & (offset_1 <= curr+1 - dictStartIndex) ) /* note: we are searching at curr+1 */ |
597 | && (MEM_read32(memPtr: repMatch) == MEM_read32(memPtr: ip+1)) ) { |
598 | const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend; |
599 | size_t const rLength = ZSTD_count_2segments(ip: ip+1 +4, match: repMatch +4, iEnd: iend, mEnd: repMatchEnd, iStart: prefixStart) + 4; |
600 | ip++; |
601 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: (size_t)(ip-anchor), literals: anchor, litLimit: iend, STORE_REPCODE_1, matchLength: rLength); |
602 | ip += rLength; |
603 | anchor = ip; |
604 | } else { |
605 | if ( (matchIndex < dictStartIndex) || |
606 | (MEM_read32(memPtr: match) != MEM_read32(memPtr: ip)) ) { |
607 | assert(stepSize >= 1); |
608 | ip += ((ip-anchor) >> kSearchStrength) + stepSize; |
609 | continue; |
610 | } |
611 | { const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend; |
612 | const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart; |
613 | U32 const offset = curr - matchIndex; |
614 | size_t mLength = ZSTD_count_2segments(ip: ip+4, match: match+4, iEnd: iend, mEnd: matchEnd, iStart: prefixStart) + 4; |
615 | while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ |
616 | offset_2 = offset_1; offset_1 = offset; /* update offset history */ |
617 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: (size_t)(ip-anchor), literals: anchor, litLimit: iend, STORE_OFFSET(offset), matchLength: mLength); |
618 | ip += mLength; |
619 | anchor = ip; |
620 | } } |
621 | |
622 | if (ip <= ilimit) { |
623 | /* Fill Table */ |
624 | hashTable[ZSTD_hashPtr(p: base+curr+2, hBits: hlog, mls)] = curr+2; |
625 | hashTable[ZSTD_hashPtr(p: ip-2, hBits: hlog, mls)] = (U32)(ip-2-base); |
626 | /* check immediate repcode */ |
627 | while (ip <= ilimit) { |
628 | U32 const current2 = (U32)(ip-base); |
629 | U32 const repIndex2 = current2 - offset_2; |
630 | const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2; |
631 | if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (offset_2 <= curr - dictStartIndex)) /* intentional overflow */ |
632 | && (MEM_read32(memPtr: repMatch2) == MEM_read32(memPtr: ip)) ) { |
633 | const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend; |
634 | size_t const repLength2 = ZSTD_count_2segments(ip: ip+4, match: repMatch2+4, iEnd: iend, mEnd: repEnd2, iStart: prefixStart) + 4; |
635 | { U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */ |
636 | ZSTD_storeSeq(seqStorePtr: seqStore, litLength: 0 /*litlen*/, literals: anchor, litLimit: iend, STORE_REPCODE_1, matchLength: repLength2); |
637 | hashTable[ZSTD_hashPtr(p: ip, hBits: hlog, mls)] = current2; |
638 | ip += repLength2; |
639 | anchor = ip; |
640 | continue; |
641 | } |
642 | break; |
643 | } } } |
644 | |
645 | /* save reps for next block */ |
646 | rep[0] = offset_1; |
647 | rep[1] = offset_2; |
648 | |
649 | /* Return the last literals size */ |
650 | return (size_t)(iend - anchor); |
651 | } |
652 | |
653 | ZSTD_GEN_FAST_FN(extDict, 4, 0) |
654 | ZSTD_GEN_FAST_FN(extDict, 5, 0) |
655 | ZSTD_GEN_FAST_FN(extDict, 6, 0) |
656 | ZSTD_GEN_FAST_FN(extDict, 7, 0) |
657 | |
658 | size_t ZSTD_compressBlock_fast_extDict( |
659 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
660 | void const* src, size_t srcSize) |
661 | { |
662 | U32 const mls = ms->cParams.minMatch; |
663 | switch(mls) |
664 | { |
665 | default: /* includes case 3 */ |
666 | case 4 : |
667 | return ZSTD_compressBlock_fast_extDict_4_0(ms, seqStore, rep, src, srcSize); |
668 | case 5 : |
669 | return ZSTD_compressBlock_fast_extDict_5_0(ms, seqStore, rep, src, srcSize); |
670 | case 6 : |
671 | return ZSTD_compressBlock_fast_extDict_6_0(ms, seqStore, rep, src, srcSize); |
672 | case 7 : |
673 | return ZSTD_compressBlock_fast_extDict_7_0(ms, seqStore, rep, src, srcSize); |
674 | } |
675 | } |
676 | |