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zstd_fast.c File Reference
#include "zstd_compress_internal.h"
#include "zstd_fast.h"
Include dependency graph for zstd_fast.c:

Go to the source code of this file.

Functions

void ZSTD_fillHashTable (ZSTD_matchState_t *ms, const void *const end, ZSTD_dictTableLoadMethod_e dtlm)
 
FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_generic (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize, U32 const mls)
 
size_t ZSTD_compressBlock_fast (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
 
FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_dictMatchState_generic (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize, U32 const mls)
 
size_t ZSTD_compressBlock_fast_dictMatchState (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
 
static size_t ZSTD_compressBlock_fast_extDict_generic (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize, U32 const mls)
 
size_t ZSTD_compressBlock_fast_extDict (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
 

Function Documentation

◆ ZSTD_compressBlock_fast()

size_t ZSTD_compressBlock_fast ( ZSTD_matchState_t ms,
seqStore_t seqStore,
U32  rep[ZSTD_REP_NUM],
void const src,
size_t  srcSize 
)

Definition at line 186 of file zstd_fast.c.

189{
190 U32 const mls = ms->cParams.minMatch;
191 assert(ms->dictMatchState == NULL);
192 switch(mls)
193 {
194 default: /* includes case 3 */
195 case 4 :
196 return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 4);
197 case 5 :
198 return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 5);
199 case 6 :
200 return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 6);
201 case 7 :
202 return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 7);
203 }
204}
void mls(int argc, const char *argv[])
Definition: cmds.c:1168
#define NULL
Definition: types.h:112
#define assert(x)
Definition: debug.h:53
GLenum src
Definition: glext.h:6340
ZSTD_compressionParameters cParams
const ZSTD_matchState_t * dictMatchState
unsigned int U32
Definition: xxhash.c:195
FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_generic(ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize, U32 const mls)
Definition: zstd_fast.c:47

Referenced by ZSTD_selectBlockCompressor().

◆ ZSTD_compressBlock_fast_dictMatchState()

size_t ZSTD_compressBlock_fast_dictMatchState ( ZSTD_matchState_t ms,
seqStore_t seqStore,
U32  rep[ZSTD_REP_NUM],
void const src,
size_t  srcSize 
)

Definition at line 354 of file zstd_fast.c.

357{
358 U32 const mls = ms->cParams.minMatch;
359 assert(ms->dictMatchState != NULL);
360 switch(mls)
361 {
362 default: /* includes case 3 */
363 case 4 :
364 return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 4);
365 case 5 :
366 return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 5);
367 case 6 :
368 return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 6);
369 case 7 :
370 return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 7);
371 }
372}
FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_dictMatchState_generic(ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize, U32 const mls)
Definition: zstd_fast.c:207

Referenced by ZSTD_selectBlockCompressor().

◆ ZSTD_compressBlock_fast_dictMatchState_generic()

FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_dictMatchState_generic ( ZSTD_matchState_t ms,
seqStore_t seqStore,
U32  rep[ZSTD_REP_NUM],
void const src,
size_t  srcSize,
U32 const  mls 
)

Definition at line 207 of file zstd_fast.c.

210{
211 const ZSTD_compressionParameters* const cParams = &ms->cParams;
212 U32* const hashTable = ms->hashTable;
213 U32 const hlog = cParams->hashLog;
214 /* support stepSize of 0 */
215 U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
216 const BYTE* const base = ms->window.base;
217 const BYTE* const istart = (const BYTE*)src;
218 const BYTE* ip = istart;
219 const BYTE* anchor = istart;
220 const U32 prefixStartIndex = ms->window.dictLimit;
221 const BYTE* const prefixStart = base + prefixStartIndex;
222 const BYTE* const iend = istart + srcSize;
223 const BYTE* const ilimit = iend - HASH_READ_SIZE;
224 U32 offset_1=rep[0], offset_2=rep[1];
225 U32 offsetSaved = 0;
226
227 const ZSTD_matchState_t* const dms = ms->dictMatchState;
228 const ZSTD_compressionParameters* const dictCParams = &dms->cParams ;
229 const U32* const dictHashTable = dms->hashTable;
230 const U32 dictStartIndex = dms->window.dictLimit;
231 const BYTE* const dictBase = dms->window.base;
232 const BYTE* const dictStart = dictBase + dictStartIndex;
233 const BYTE* const dictEnd = dms->window.nextSrc;
234 const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase);
235 const U32 dictAndPrefixLength = (U32)(ip - prefixStart + dictEnd - dictStart);
236 const U32 dictHLog = dictCParams->hashLog;
237
238 /* if a dictionary is still attached, it necessarily means that
239 * it is within window size. So we just check it. */
240 const U32 maxDistance = 1U << cParams->windowLog;
241 const U32 endIndex = (U32)((size_t)(ip - base) + srcSize);
242 assert(endIndex - prefixStartIndex <= maxDistance);
243 (void)maxDistance; (void)endIndex; /* these variables are not used when assert() is disabled */
244
245 /* ensure there will be no no underflow
246 * when translating a dict index into a local index */
247 assert(prefixStartIndex >= (U32)(dictEnd - dictBase));
248
249 /* init */
250 DEBUGLOG(5, "ZSTD_compressBlock_fast_dictMatchState_generic");
251 ip += (dictAndPrefixLength == 0);
252 /* dictMatchState repCode checks don't currently handle repCode == 0
253 * disabling. */
254 assert(offset_1 <= dictAndPrefixLength);
255 assert(offset_2 <= dictAndPrefixLength);
256
257 /* Main Search Loop */
258 while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
259 size_t mLength;
260 size_t const h = ZSTD_hashPtr(ip, hlog, mls);
261 U32 const current = (U32)(ip-base);
262 U32 const matchIndex = hashTable[h];
263 const BYTE* match = base + matchIndex;
264 const U32 repIndex = current + 1 - offset_1;
265 const BYTE* repMatch = (repIndex < prefixStartIndex) ?
266 dictBase + (repIndex - dictIndexDelta) :
267 base + repIndex;
268 hashTable[h] = current; /* update hash table */
269
270 if ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex isn't overlapping dict + prefix */
271 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
272 const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
273 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
274 ip++;
275 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
276 } else if ( (matchIndex <= prefixStartIndex) ) {
277 size_t const dictHash = ZSTD_hashPtr(ip, dictHLog, mls);
278 U32 const dictMatchIndex = dictHashTable[dictHash];
279 const BYTE* dictMatch = dictBase + dictMatchIndex;
280 if (dictMatchIndex <= dictStartIndex ||
281 MEM_read32(dictMatch) != MEM_read32(ip)) {
282 assert(stepSize >= 1);
283 ip += ((ip-anchor) >> kSearchStrength) + stepSize;
284 continue;
285 } else {
286 /* found a dict match */
287 U32 const offset = (U32)(current-dictMatchIndex-dictIndexDelta);
288 mLength = ZSTD_count_2segments(ip+4, dictMatch+4, iend, dictEnd, prefixStart) + 4;
289 while (((ip>anchor) & (dictMatch>dictStart))
290 && (ip[-1] == dictMatch[-1])) {
291 ip--; dictMatch--; mLength++;
292 } /* catch up */
293 offset_2 = offset_1;
294 offset_1 = offset;
295 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
296 }
297 } else if (MEM_read32(match) != MEM_read32(ip)) {
298 /* it's not a match, and we're not going to check the dictionary */
299 assert(stepSize >= 1);
300 ip += ((ip-anchor) >> kSearchStrength) + stepSize;
301 continue;
302 } else {
303 /* found a regular match */
304 U32 const offset = (U32)(ip-match);
305 mLength = ZSTD_count(ip+4, match+4, iend) + 4;
306 while (((ip>anchor) & (match>prefixStart))
307 && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
308 offset_2 = offset_1;
309 offset_1 = offset;
310 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
311 }
312
313 /* match found */
314 ip += mLength;
315 anchor = ip;
316
317 if (ip <= ilimit) {
318 /* Fill Table */
319 assert(base+current+2 > istart); /* check base overflow */
320 hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2; /* here because current+2 could be > iend-8 */
321 hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base);
322
323 /* check immediate repcode */
324 while (ip <= ilimit) {
325 U32 const current2 = (U32)(ip-base);
326 U32 const repIndex2 = current2 - offset_2;
327 const BYTE* repMatch2 = repIndex2 < prefixStartIndex ?
328 dictBase - dictIndexDelta + repIndex2 :
329 base + repIndex2;
330 if ( ((U32)((prefixStartIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */)
331 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
332 const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
333 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
334 U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
335 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
336 hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2;
337 ip += repLength2;
338 anchor = ip;
339 continue;
340 }
341 break;
342 }
343 }
344 }
345
346 /* save reps for next block */
347 rep[0] = offset_1 ? offset_1 : offsetSaved;
348 rep[1] = offset_2 ? offset_2 : offsetSaved;
349
350 /* Return the last literals size */
351 return (size_t)(iend - anchor);
352}
#define DEBUGLOG(l,...)
Definition: debug.h:106
MEM_STATIC U32 MEM_read32(const void *memPtr)
Definition: mem.h:242
GLintptr offset
Definition: glext.h:5920
GLfloat GLfloat GLfloat GLfloat h
Definition: glext.h:7723
struct task_struct * current
Definition: linux.c:32
Definition: dhcpd.h:62
Definition: match.c:28
unsigned char BYTE
Definition: xxhash.c:193
MEM_STATIC size_t ZSTD_count_2segments(const BYTE *ip, const BYTE *match, const BYTE *iEnd, const BYTE *mEnd, const BYTE *iStart)
#define kSearchStrength
MEM_STATIC size_t ZSTD_hashPtr(const void *p, U32 hBits, U32 mls)
MEM_STATIC size_t ZSTD_count(const BYTE *pIn, const BYTE *pMatch, const BYTE *const pInLimit)
HINT_INLINE UNUSED_ATTR void ZSTD_storeSeq(seqStore_t *seqStorePtr, size_t litLength, const BYTE *literals, const BYTE *litLimit, U32 offCode, size_t mlBase)
#define HASH_READ_SIZE
#define MINMATCH
#define ZSTD_REP_MOVE

Referenced by ZSTD_compressBlock_fast_dictMatchState().

◆ ZSTD_compressBlock_fast_extDict()

size_t ZSTD_compressBlock_fast_extDict ( ZSTD_matchState_t ms,
seqStore_t seqStore,
U32  rep[ZSTD_REP_NUM],
void const src,
size_t  srcSize 
)

Definition at line 479 of file zstd_fast.c.

482{
483 U32 const mls = ms->cParams.minMatch;
484 switch(mls)
485 {
486 default: /* includes case 3 */
487 case 4 :
488 return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 4);
489 case 5 :
490 return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 5);
491 case 6 :
492 return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 6);
493 case 7 :
494 return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 7);
495 }
496}
static size_t ZSTD_compressBlock_fast_extDict_generic(ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize, U32 const mls)
Definition: zstd_fast.c:375

Referenced by ZSTD_selectBlockCompressor().

◆ ZSTD_compressBlock_fast_extDict_generic()

static size_t ZSTD_compressBlock_fast_extDict_generic ( ZSTD_matchState_t ms,
seqStore_t seqStore,
U32  rep[ZSTD_REP_NUM],
void const src,
size_t  srcSize,
U32 const  mls 
)
static

Definition at line 375 of file zstd_fast.c.

378{
379 const ZSTD_compressionParameters* const cParams = &ms->cParams;
380 U32* const hashTable = ms->hashTable;
381 U32 const hlog = cParams->hashLog;
382 /* support stepSize of 0 */
383 U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
384 const BYTE* const base = ms->window.base;
385 const BYTE* const dictBase = ms->window.dictBase;
386 const BYTE* const istart = (const BYTE*)src;
387 const BYTE* ip = istart;
388 const BYTE* anchor = istart;
389 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
390 const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
391 const U32 dictStartIndex = lowLimit;
392 const BYTE* const dictStart = dictBase + dictStartIndex;
393 const U32 dictLimit = ms->window.dictLimit;
394 const U32 prefixStartIndex = dictLimit < lowLimit ? lowLimit : dictLimit;
395 const BYTE* const prefixStart = base + prefixStartIndex;
396 const BYTE* const dictEnd = dictBase + prefixStartIndex;
397 const BYTE* const iend = istart + srcSize;
398 const BYTE* const ilimit = iend - 8;
399 U32 offset_1=rep[0], offset_2=rep[1];
400
401 DEBUGLOG(5, "ZSTD_compressBlock_fast_extDict_generic (offset_1=%u)", offset_1);
402
403 /* switch to "regular" variant if extDict is invalidated due to maxDistance */
404 if (prefixStartIndex == dictStartIndex)
405 return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, mls);
406
407 /* Search Loop */
408 while (ip < ilimit) { /* < instead of <=, because (ip+1) */
409 const size_t h = ZSTD_hashPtr(ip, hlog, mls);
410 const U32 matchIndex = hashTable[h];
411 const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
412 const BYTE* match = matchBase + matchIndex;
413 const U32 current = (U32)(ip-base);
414 const U32 repIndex = current + 1 - offset_1;
415 const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
416 const BYTE* const repMatch = repBase + repIndex;
417 hashTable[h] = current; /* update hash table */
418 DEBUGLOG(7, "offset_1 = %u , current = %u", offset_1, current);
419 assert(offset_1 <= current +1); /* check repIndex */
420
421 if ( (((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > dictStartIndex))
422 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
423 const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
424 size_t const rLength = ZSTD_count_2segments(ip+1 +4, repMatch +4, iend, repMatchEnd, prefixStart) + 4;
425 ip++;
426 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, rLength-MINMATCH);
427 ip += rLength;
428 anchor = ip;
429 } else {
430 if ( (matchIndex < dictStartIndex) ||
431 (MEM_read32(match) != MEM_read32(ip)) ) {
432 assert(stepSize >= 1);
433 ip += ((ip-anchor) >> kSearchStrength) + stepSize;
434 continue;
435 }
436 { const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
437 const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
438 U32 const offset = current - matchIndex;
439 size_t mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
440 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
441 offset_2 = offset_1; offset_1 = offset; /* update offset history */
442 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
443 ip += mLength;
444 anchor = ip;
445 } }
446
447 if (ip <= ilimit) {
448 /* Fill Table */
449 hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2;
450 hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base);
451 /* check immediate repcode */
452 while (ip <= ilimit) {
453 U32 const current2 = (U32)(ip-base);
454 U32 const repIndex2 = current2 - offset_2;
455 const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
456 if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (repIndex2 > dictStartIndex)) /* intentional overflow */
457 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
458 const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
459 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
460 { U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */
461 ZSTD_storeSeq(seqStore, 0 /*litlen*/, anchor, iend, 0 /*offcode*/, repLength2-MINMATCH);
462 hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2;
463 ip += repLength2;
464 anchor = ip;
465 continue;
466 }
467 break;
468 } } }
469
470 /* save reps for next block */
471 rep[0] = offset_1;
472 rep[1] = offset_2;
473
474 /* Return the last literals size */
475 return (size_t)(iend - anchor);
476}
MEM_STATIC U32 ZSTD_getLowestMatchIndex(const ZSTD_matchState_t *ms, U32 current, unsigned windowLog)

Referenced by ZSTD_compressBlock_fast_extDict().

◆ ZSTD_compressBlock_fast_generic()

FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_generic ( ZSTD_matchState_t ms,
seqStore_t seqStore,
U32  rep[ZSTD_REP_NUM],
void const src,
size_t  srcSize,
U32 const  mls 
)

Definition at line 47 of file zstd_fast.c.

51{
52 const ZSTD_compressionParameters* const cParams = &ms->cParams;
53 U32* const hashTable = ms->hashTable;
54 U32 const hlog = cParams->hashLog;
55 /* support stepSize of 0 */
56 size_t const stepSize = cParams->targetLength + !(cParams->targetLength) + 1;
57 const BYTE* const base = ms->window.base;
58 const BYTE* const istart = (const BYTE*)src;
59 /* We check ip0 (ip + 0) and ip1 (ip + 1) each loop */
60 const BYTE* ip0 = istart;
61 const BYTE* ip1;
62 const BYTE* anchor = istart;
63 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
64 const U32 prefixStartIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
65 const BYTE* const prefixStart = base + prefixStartIndex;
66 const BYTE* const iend = istart + srcSize;
67 const BYTE* const ilimit = iend - HASH_READ_SIZE;
68 U32 offset_1=rep[0], offset_2=rep[1];
69 U32 offsetSaved = 0;
70
71 /* init */
72 DEBUGLOG(5, "ZSTD_compressBlock_fast_generic");
73 ip0 += (ip0 == prefixStart);
74 ip1 = ip0 + 1;
75 { U32 const current = (U32)(ip0 - base);
76 U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, cParams->windowLog);
77 U32 const maxRep = current - windowLow;
78 if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
79 if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
80 }
81
82 /* Main Search Loop */
83#ifdef __INTEL_COMPILER
84 /* From intel 'The vector pragma indicates that the loop should be
85 * vectorized if it is legal to do so'. Can be used together with
86 * #pragma ivdep (but have opted to exclude that because intel
87 * warns against using it).*/
88 #pragma vector always
89#endif
90 while (ip1 < ilimit) { /* < instead of <=, because check at ip0+2 */
91 size_t mLength;
92 BYTE const* ip2 = ip0 + 2;
93 size_t const h0 = ZSTD_hashPtr(ip0, hlog, mls);
94 U32 const val0 = MEM_read32(ip0);
95 size_t const h1 = ZSTD_hashPtr(ip1, hlog, mls);
96 U32 const val1 = MEM_read32(ip1);
97 U32 const current0 = (U32)(ip0-base);
98 U32 const current1 = (U32)(ip1-base);
99 U32 const matchIndex0 = hashTable[h0];
100 U32 const matchIndex1 = hashTable[h1];
101 BYTE const* repMatch = ip2 - offset_1;
102 const BYTE* match0 = base + matchIndex0;
103 const BYTE* match1 = base + matchIndex1;
104 U32 offcode;
105
106#if defined(__aarch64__)
107 PREFETCH_L1(ip0+256);
108#endif
109
110 hashTable[h0] = current0; /* update hash table */
111 hashTable[h1] = current1; /* update hash table */
112
113 assert(ip0 + 1 == ip1);
114
115 if ((offset_1 > 0) & (MEM_read32(repMatch) == MEM_read32(ip2))) {
116 mLength = (ip2[-1] == repMatch[-1]) ? 1 : 0;
117 ip0 = ip2 - mLength;
118 match0 = repMatch - mLength;
119 mLength += 4;
120 offcode = 0;
121 goto _match;
122 }
123 if ((matchIndex0 > prefixStartIndex) && MEM_read32(match0) == val0) {
124 /* found a regular match */
125 goto _offset;
126 }
127 if ((matchIndex1 > prefixStartIndex) && MEM_read32(match1) == val1) {
128 /* found a regular match after one literal */
129 ip0 = ip1;
130 match0 = match1;
131 goto _offset;
132 }
133 { size_t const step = ((size_t)(ip0-anchor) >> (kSearchStrength - 1)) + stepSize;
134 assert(step >= 2);
135 ip0 += step;
136 ip1 += step;
137 continue;
138 }
139_offset: /* Requires: ip0, match0 */
140 /* Compute the offset code */
141 offset_2 = offset_1;
142 offset_1 = (U32)(ip0-match0);
143 offcode = offset_1 + ZSTD_REP_MOVE;
144 mLength = 4;
145 /* Count the backwards match length */
146 while (((ip0>anchor) & (match0>prefixStart))
147 && (ip0[-1] == match0[-1])) { ip0--; match0--; mLength++; } /* catch up */
148
149_match: /* Requires: ip0, match0, offcode */
150 /* Count the forward length */
151 mLength += ZSTD_count(ip0+mLength, match0+mLength, iend);
152 ZSTD_storeSeq(seqStore, (size_t)(ip0-anchor), anchor, iend, offcode, mLength-MINMATCH);
153 /* match found */
154 ip0 += mLength;
155 anchor = ip0;
156
157 if (ip0 <= ilimit) {
158 /* Fill Table */
159 assert(base+current0+2 > istart); /* check base overflow */
160 hashTable[ZSTD_hashPtr(base+current0+2, hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */
161 hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
162
163 if (offset_2 > 0) { /* offset_2==0 means offset_2 is invalidated */
164 while ( (ip0 <= ilimit) && (MEM_read32(ip0) == MEM_read32(ip0 - offset_2)) ) {
165 /* store sequence */
166 size_t const rLength = ZSTD_count(ip0+4, ip0+4-offset_2, iend) + 4;
167 { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */
168 hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base);
169 ip0 += rLength;
170 ZSTD_storeSeq(seqStore, 0 /*litLen*/, anchor, iend, 0 /*offCode*/, rLength-MINMATCH);
171 anchor = ip0;
172 continue; /* faster when present (confirmed on gcc-8) ... (?) */
173 } } }
174 ip1 = ip0 + 1;
175 }
176
177 /* save reps for next block */
178 rep[0] = offset_1 ? offset_1 : offsetSaved;
179 rep[1] = offset_2 ? offset_2 : offsetSaved;
180
181 /* Return the last literals size */
182 return (size_t)(iend - anchor);
183}
#define PREFETCH_L1(ptr)
Definition: compiler.h:124
__kernel_size_t size_t
Definition: linux.h:237
MEM_STATIC U32 ZSTD_getLowestPrefixIndex(const ZSTD_matchState_t *ms, U32 current, unsigned windowLog)

Referenced by ZSTD_compressBlock_fast(), and ZSTD_compressBlock_fast_extDict_generic().

◆ ZSTD_fillHashTable()

void ZSTD_fillHashTable ( ZSTD_matchState_t ms,
const void *const  end,
ZSTD_dictTableLoadMethod_e  dtlm 
)

Definition at line 15 of file zstd_fast.c.

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 current = (U32)(ip - base);
33 size_t const hash0 = ZSTD_hashPtr(ip, hBits, mls);
34 hashTable[hash0] = current;
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(ip + p, hBits, mls);
40 if (hashTable[hash] == 0) { /* not yet filled */
41 hashTable[hash] = current + p;
42 } } } }
43}
GLuint GLuint end
Definition: gl.h:1545
GLfloat GLfloat p
Definition: glext.h:8902
Definition: _hash_fun.h:40
@ ZSTD_dtlm_fast

Referenced by ZSTD_ldm_fillFastTables(), and ZSTD_loadDictionaryContent().