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-rw-r--r--vendor/github.com/klauspost/compress/s2/encode_go.go729
1 files changed, 0 insertions, 729 deletions
diff --git a/vendor/github.com/klauspost/compress/s2/encode_go.go b/vendor/github.com/klauspost/compress/s2/encode_go.go
deleted file mode 100644
index 6b393c3..0000000
--- a/vendor/github.com/klauspost/compress/s2/encode_go.go
+++ /dev/null
@@ -1,729 +0,0 @@
1//go:build !amd64 || appengine || !gc || noasm
2// +build !amd64 appengine !gc noasm
3
4package s2
5
6import (
7 "bytes"
8 "math/bits"
9)
10
11const hasAmd64Asm = false
12
13// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
14// assumes that the varint-encoded length of the decompressed bytes has already
15// been written.
16//
17// It also assumes that:
18//
19// len(dst) >= MaxEncodedLen(len(src))
20func encodeBlock(dst, src []byte) (d int) {
21 if len(src) < minNonLiteralBlockSize {
22 return 0
23 }
24 return encodeBlockGo(dst, src)
25}
26
27// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
28// assumes that the varint-encoded length of the decompressed bytes has already
29// been written.
30//
31// It also assumes that:
32//
33// len(dst) >= MaxEncodedLen(len(src))
34func encodeBlockBetter(dst, src []byte) (d int) {
35 return encodeBlockBetterGo(dst, src)
36}
37
38// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
39// assumes that the varint-encoded length of the decompressed bytes has already
40// been written.
41//
42// It also assumes that:
43//
44// len(dst) >= MaxEncodedLen(len(src))
45func encodeBlockBetterSnappy(dst, src []byte) (d int) {
46 return encodeBlockBetterSnappyGo(dst, src)
47}
48
49// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
50// assumes that the varint-encoded length of the decompressed bytes has already
51// been written.
52//
53// It also assumes that:
54//
55// len(dst) >= MaxEncodedLen(len(src))
56func encodeBlockSnappy(dst, src []byte) (d int) {
57 if len(src) < minNonLiteralBlockSize {
58 return 0
59 }
60 return encodeBlockSnappyGo(dst, src)
61}
62
63// emitLiteral writes a literal chunk and returns the number of bytes written.
64//
65// It assumes that:
66//
67// dst is long enough to hold the encoded bytes
68// 0 <= len(lit) && len(lit) <= math.MaxUint32
69func emitLiteral(dst, lit []byte) int {
70 if len(lit) == 0 {
71 return 0
72 }
73 const num = 63<<2 | tagLiteral
74 i, n := 0, uint(len(lit)-1)
75 switch {
76 case n < 60:
77 dst[0] = uint8(n)<<2 | tagLiteral
78 i = 1
79 case n < 1<<8:
80 dst[1] = uint8(n)
81 dst[0] = 60<<2 | tagLiteral
82 i = 2
83 case n < 1<<16:
84 dst[2] = uint8(n >> 8)
85 dst[1] = uint8(n)
86 dst[0] = 61<<2 | tagLiteral
87 i = 3
88 case n < 1<<24:
89 dst[3] = uint8(n >> 16)
90 dst[2] = uint8(n >> 8)
91 dst[1] = uint8(n)
92 dst[0] = 62<<2 | tagLiteral
93 i = 4
94 default:
95 dst[4] = uint8(n >> 24)
96 dst[3] = uint8(n >> 16)
97 dst[2] = uint8(n >> 8)
98 dst[1] = uint8(n)
99 dst[0] = 63<<2 | tagLiteral
100 i = 5
101 }
102 return i + copy(dst[i:], lit)
103}
104
105// emitRepeat writes a repeat chunk and returns the number of bytes written.
106// Length must be at least 4 and < 1<<24
107func emitRepeat(dst []byte, offset, length int) int {
108 // Repeat offset, make length cheaper
109 length -= 4
110 if length <= 4 {
111 dst[0] = uint8(length)<<2 | tagCopy1
112 dst[1] = 0
113 return 2
114 }
115 if length < 8 && offset < 2048 {
116 // Encode WITH offset
117 dst[1] = uint8(offset)
118 dst[0] = uint8(offset>>8)<<5 | uint8(length)<<2 | tagCopy1
119 return 2
120 }
121 if length < (1<<8)+4 {
122 length -= 4
123 dst[2] = uint8(length)
124 dst[1] = 0
125 dst[0] = 5<<2 | tagCopy1
126 return 3
127 }
128 if length < (1<<16)+(1<<8) {
129 length -= 1 << 8
130 dst[3] = uint8(length >> 8)
131 dst[2] = uint8(length >> 0)
132 dst[1] = 0
133 dst[0] = 6<<2 | tagCopy1
134 return 4
135 }
136 const maxRepeat = (1 << 24) - 1
137 length -= 1 << 16
138 left := 0
139 if length > maxRepeat {
140 left = length - maxRepeat + 4
141 length = maxRepeat - 4
142 }
143 dst[4] = uint8(length >> 16)
144 dst[3] = uint8(length >> 8)
145 dst[2] = uint8(length >> 0)
146 dst[1] = 0
147 dst[0] = 7<<2 | tagCopy1
148 if left > 0 {
149 return 5 + emitRepeat(dst[5:], offset, left)
150 }
151 return 5
152}
153
154// emitCopy writes a copy chunk and returns the number of bytes written.
155//
156// It assumes that:
157//
158// dst is long enough to hold the encoded bytes
159// 1 <= offset && offset <= math.MaxUint32
160// 4 <= length && length <= 1 << 24
161func emitCopy(dst []byte, offset, length int) int {
162 if offset >= 65536 {
163 i := 0
164 if length > 64 {
165 // Emit a length 64 copy, encoded as 5 bytes.
166 dst[4] = uint8(offset >> 24)
167 dst[3] = uint8(offset >> 16)
168 dst[2] = uint8(offset >> 8)
169 dst[1] = uint8(offset)
170 dst[0] = 63<<2 | tagCopy4
171 length -= 64
172 if length >= 4 {
173 // Emit remaining as repeats
174 return 5 + emitRepeat(dst[5:], offset, length)
175 }
176 i = 5
177 }
178 if length == 0 {
179 return i
180 }
181 // Emit a copy, offset encoded as 4 bytes.
182 dst[i+0] = uint8(length-1)<<2 | tagCopy4
183 dst[i+1] = uint8(offset)
184 dst[i+2] = uint8(offset >> 8)
185 dst[i+3] = uint8(offset >> 16)
186 dst[i+4] = uint8(offset >> 24)
187 return i + 5
188 }
189
190 // Offset no more than 2 bytes.
191 if length > 64 {
192 off := 3
193 if offset < 2048 {
194 // emit 8 bytes as tagCopy1, rest as repeats.
195 dst[1] = uint8(offset)
196 dst[0] = uint8(offset>>8)<<5 | uint8(8-4)<<2 | tagCopy1
197 length -= 8
198 off = 2
199 } else {
200 // Emit a length 60 copy, encoded as 3 bytes.
201 // Emit remaining as repeat value (minimum 4 bytes).
202 dst[2] = uint8(offset >> 8)
203 dst[1] = uint8(offset)
204 dst[0] = 59<<2 | tagCopy2
205 length -= 60
206 }
207 // Emit remaining as repeats, at least 4 bytes remain.
208 return off + emitRepeat(dst[off:], offset, length)
209 }
210 if length >= 12 || offset >= 2048 {
211 // Emit the remaining copy, encoded as 3 bytes.
212 dst[2] = uint8(offset >> 8)
213 dst[1] = uint8(offset)
214 dst[0] = uint8(length-1)<<2 | tagCopy2
215 return 3
216 }
217 // Emit the remaining copy, encoded as 2 bytes.
218 dst[1] = uint8(offset)
219 dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
220 return 2
221}
222
223// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
224//
225// It assumes that:
226//
227// dst is long enough to hold the encoded bytes
228// 1 <= offset && offset <= math.MaxUint32
229// 4 <= length && length <= 1 << 24
230func emitCopyNoRepeat(dst []byte, offset, length int) int {
231 if offset >= 65536 {
232 i := 0
233 if length > 64 {
234 // Emit a length 64 copy, encoded as 5 bytes.
235 dst[4] = uint8(offset >> 24)
236 dst[3] = uint8(offset >> 16)
237 dst[2] = uint8(offset >> 8)
238 dst[1] = uint8(offset)
239 dst[0] = 63<<2 | tagCopy4
240 length -= 64
241 if length >= 4 {
242 // Emit remaining as repeats
243 return 5 + emitCopyNoRepeat(dst[5:], offset, length)
244 }
245 i = 5
246 }
247 if length == 0 {
248 return i
249 }
250 // Emit a copy, offset encoded as 4 bytes.
251 dst[i+0] = uint8(length-1)<<2 | tagCopy4
252 dst[i+1] = uint8(offset)
253 dst[i+2] = uint8(offset >> 8)
254 dst[i+3] = uint8(offset >> 16)
255 dst[i+4] = uint8(offset >> 24)
256 return i + 5
257 }
258
259 // Offset no more than 2 bytes.
260 if length > 64 {
261 // Emit a length 60 copy, encoded as 3 bytes.
262 // Emit remaining as repeat value (minimum 4 bytes).
263 dst[2] = uint8(offset >> 8)
264 dst[1] = uint8(offset)
265 dst[0] = 59<<2 | tagCopy2
266 length -= 60
267 // Emit remaining as repeats, at least 4 bytes remain.
268 return 3 + emitCopyNoRepeat(dst[3:], offset, length)
269 }
270 if length >= 12 || offset >= 2048 {
271 // Emit the remaining copy, encoded as 3 bytes.
272 dst[2] = uint8(offset >> 8)
273 dst[1] = uint8(offset)
274 dst[0] = uint8(length-1)<<2 | tagCopy2
275 return 3
276 }
277 // Emit the remaining copy, encoded as 2 bytes.
278 dst[1] = uint8(offset)
279 dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
280 return 2
281}
282
283// matchLen returns how many bytes match in a and b
284//
285// It assumes that:
286//
287// len(a) <= len(b)
288func matchLen(a []byte, b []byte) int {
289 b = b[:len(a)]
290 var checked int
291 if len(a) > 4 {
292 // Try 4 bytes first
293 if diff := load32(a, 0) ^ load32(b, 0); diff != 0 {
294 return bits.TrailingZeros32(diff) >> 3
295 }
296 // Switch to 8 byte matching.
297 checked = 4
298 a = a[4:]
299 b = b[4:]
300 for len(a) >= 8 {
301 b = b[:len(a)]
302 if diff := load64(a, 0) ^ load64(b, 0); diff != 0 {
303 return checked + (bits.TrailingZeros64(diff) >> 3)
304 }
305 checked += 8
306 a = a[8:]
307 b = b[8:]
308 }
309 }
310 b = b[:len(a)]
311 for i := range a {
312 if a[i] != b[i] {
313 return int(i) + checked
314 }
315 }
316 return len(a) + checked
317}
318
319// input must be > inputMargin
320func calcBlockSize(src []byte) (d int) {
321 // Initialize the hash table.
322 const (
323 tableBits = 13
324 maxTableSize = 1 << tableBits
325 )
326
327 var table [maxTableSize]uint32
328
329 // sLimit is when to stop looking for offset/length copies. The inputMargin
330 // lets us use a fast path for emitLiteral in the main loop, while we are
331 // looking for copies.
332 sLimit := len(src) - inputMargin
333
334 // Bail if we can't compress to at least this.
335 dstLimit := len(src) - len(src)>>5 - 5
336
337 // nextEmit is where in src the next emitLiteral should start from.
338 nextEmit := 0
339
340 // The encoded form must start with a literal, as there are no previous
341 // bytes to copy, so we start looking for hash matches at s == 1.
342 s := 1
343 cv := load64(src, s)
344
345 // We search for a repeat at -1, but don't output repeats when nextEmit == 0
346 repeat := 1
347
348 for {
349 candidate := 0
350 for {
351 // Next src position to check
352 nextS := s + (s-nextEmit)>>6 + 4
353 if nextS > sLimit {
354 goto emitRemainder
355 }
356 hash0 := hash6(cv, tableBits)
357 hash1 := hash6(cv>>8, tableBits)
358 candidate = int(table[hash0])
359 candidate2 := int(table[hash1])
360 table[hash0] = uint32(s)
361 table[hash1] = uint32(s + 1)
362 hash2 := hash6(cv>>16, tableBits)
363
364 // Check repeat at offset checkRep.
365 const checkRep = 1
366 if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
367 base := s + checkRep
368 // Extend back
369 for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
370 i--
371 base--
372 }
373 d += emitLiteralSize(src[nextEmit:base])
374
375 // Extend forward
376 candidate := s - repeat + 4 + checkRep
377 s += 4 + checkRep
378 for s <= sLimit {
379 if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
380 s += bits.TrailingZeros64(diff) >> 3
381 break
382 }
383 s += 8
384 candidate += 8
385 }
386
387 d += emitCopyNoRepeatSize(repeat, s-base)
388 nextEmit = s
389 if s >= sLimit {
390 goto emitRemainder
391 }
392
393 cv = load64(src, s)
394 continue
395 }
396
397 if uint32(cv) == load32(src, candidate) {
398 break
399 }
400 candidate = int(table[hash2])
401 if uint32(cv>>8) == load32(src, candidate2) {
402 table[hash2] = uint32(s + 2)
403 candidate = candidate2
404 s++
405 break
406 }
407 table[hash2] = uint32(s + 2)
408 if uint32(cv>>16) == load32(src, candidate) {
409 s += 2
410 break
411 }
412
413 cv = load64(src, nextS)
414 s = nextS
415 }
416
417 // Extend backwards
418 for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
419 candidate--
420 s--
421 }
422
423 // Bail if we exceed the maximum size.
424 if d+(s-nextEmit) > dstLimit {
425 return 0
426 }
427
428 // A 4-byte match has been found. We'll later see if more than 4 bytes
429 // match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
430 // them as literal bytes.
431
432 d += emitLiteralSize(src[nextEmit:s])
433
434 // Call emitCopy, and then see if another emitCopy could be our next
435 // move. Repeat until we find no match for the input immediately after
436 // what was consumed by the last emitCopy call.
437 //
438 // If we exit this loop normally then we need to call emitLiteral next,
439 // though we don't yet know how big the literal will be. We handle that
440 // by proceeding to the next iteration of the main loop. We also can
441 // exit this loop via goto if we get close to exhausting the input.
442 for {
443 // Invariant: we have a 4-byte match at s, and no need to emit any
444 // literal bytes prior to s.
445 base := s
446 repeat = base - candidate
447
448 // Extend the 4-byte match as long as possible.
449 s += 4
450 candidate += 4
451 for s <= len(src)-8 {
452 if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
453 s += bits.TrailingZeros64(diff) >> 3
454 break
455 }
456 s += 8
457 candidate += 8
458 }
459
460 d += emitCopyNoRepeatSize(repeat, s-base)
461 if false {
462 // Validate match.
463 a := src[base:s]
464 b := src[base-repeat : base-repeat+(s-base)]
465 if !bytes.Equal(a, b) {
466 panic("mismatch")
467 }
468 }
469
470 nextEmit = s
471 if s >= sLimit {
472 goto emitRemainder
473 }
474
475 if d > dstLimit {
476 // Do we have space for more, if not bail.
477 return 0
478 }
479 // Check for an immediate match, otherwise start search at s+1
480 x := load64(src, s-2)
481 m2Hash := hash6(x, tableBits)
482 currHash := hash6(x>>16, tableBits)
483 candidate = int(table[currHash])
484 table[m2Hash] = uint32(s - 2)
485 table[currHash] = uint32(s)
486 if uint32(x>>16) != load32(src, candidate) {
487 cv = load64(src, s+1)
488 s++
489 break
490 }
491 }
492 }
493
494emitRemainder:
495 if nextEmit < len(src) {
496 // Bail if we exceed the maximum size.
497 if d+len(src)-nextEmit > dstLimit {
498 return 0
499 }
500 d += emitLiteralSize(src[nextEmit:])
501 }
502 return d
503}
504
505// length must be > inputMargin.
506func calcBlockSizeSmall(src []byte) (d int) {
507 // Initialize the hash table.
508 const (
509 tableBits = 9
510 maxTableSize = 1 << tableBits
511 )
512
513 var table [maxTableSize]uint32
514
515 // sLimit is when to stop looking for offset/length copies. The inputMargin
516 // lets us use a fast path for emitLiteral in the main loop, while we are
517 // looking for copies.
518 sLimit := len(src) - inputMargin
519
520 // Bail if we can't compress to at least this.
521 dstLimit := len(src) - len(src)>>5 - 5
522
523 // nextEmit is where in src the next emitLiteral should start from.
524 nextEmit := 0
525
526 // The encoded form must start with a literal, as there are no previous
527 // bytes to copy, so we start looking for hash matches at s == 1.
528 s := 1
529 cv := load64(src, s)
530
531 // We search for a repeat at -1, but don't output repeats when nextEmit == 0
532 repeat := 1
533
534 for {
535 candidate := 0
536 for {
537 // Next src position to check
538 nextS := s + (s-nextEmit)>>6 + 4
539 if nextS > sLimit {
540 goto emitRemainder
541 }
542 hash0 := hash6(cv, tableBits)
543 hash1 := hash6(cv>>8, tableBits)
544 candidate = int(table[hash0])
545 candidate2 := int(table[hash1])
546 table[hash0] = uint32(s)
547 table[hash1] = uint32(s + 1)
548 hash2 := hash6(cv>>16, tableBits)
549
550 // Check repeat at offset checkRep.
551 const checkRep = 1
552 if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
553 base := s + checkRep
554 // Extend back
555 for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
556 i--
557 base--
558 }
559 d += emitLiteralSize(src[nextEmit:base])
560
561 // Extend forward
562 candidate := s - repeat + 4 + checkRep
563 s += 4 + checkRep
564 for s <= sLimit {
565 if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
566 s += bits.TrailingZeros64(diff) >> 3
567 break
568 }
569 s += 8
570 candidate += 8
571 }
572
573 d += emitCopyNoRepeatSize(repeat, s-base)
574 nextEmit = s
575 if s >= sLimit {
576 goto emitRemainder
577 }
578
579 cv = load64(src, s)
580 continue
581 }
582
583 if uint32(cv) == load32(src, candidate) {
584 break
585 }
586 candidate = int(table[hash2])
587 if uint32(cv>>8) == load32(src, candidate2) {
588 table[hash2] = uint32(s + 2)
589 candidate = candidate2
590 s++
591 break
592 }
593 table[hash2] = uint32(s + 2)
594 if uint32(cv>>16) == load32(src, candidate) {
595 s += 2
596 break
597 }
598
599 cv = load64(src, nextS)
600 s = nextS
601 }
602
603 // Extend backwards
604 for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
605 candidate--
606 s--
607 }
608
609 // Bail if we exceed the maximum size.
610 if d+(s-nextEmit) > dstLimit {
611 return 0
612 }
613
614 // A 4-byte match has been found. We'll later see if more than 4 bytes
615 // match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
616 // them as literal bytes.
617
618 d += emitLiteralSize(src[nextEmit:s])
619
620 // Call emitCopy, and then see if another emitCopy could be our next
621 // move. Repeat until we find no match for the input immediately after
622 // what was consumed by the last emitCopy call.
623 //
624 // If we exit this loop normally then we need to call emitLiteral next,
625 // though we don't yet know how big the literal will be. We handle that
626 // by proceeding to the next iteration of the main loop. We also can
627 // exit this loop via goto if we get close to exhausting the input.
628 for {
629 // Invariant: we have a 4-byte match at s, and no need to emit any
630 // literal bytes prior to s.
631 base := s
632 repeat = base - candidate
633
634 // Extend the 4-byte match as long as possible.
635 s += 4
636 candidate += 4
637 for s <= len(src)-8 {
638 if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
639 s += bits.TrailingZeros64(diff) >> 3
640 break
641 }
642 s += 8
643 candidate += 8
644 }
645
646 d += emitCopyNoRepeatSize(repeat, s-base)
647 if false {
648 // Validate match.
649 a := src[base:s]
650 b := src[base-repeat : base-repeat+(s-base)]
651 if !bytes.Equal(a, b) {
652 panic("mismatch")
653 }
654 }
655
656 nextEmit = s
657 if s >= sLimit {
658 goto emitRemainder
659 }
660
661 if d > dstLimit {
662 // Do we have space for more, if not bail.
663 return 0
664 }
665 // Check for an immediate match, otherwise start search at s+1
666 x := load64(src, s-2)
667 m2Hash := hash6(x, tableBits)
668 currHash := hash6(x>>16, tableBits)
669 candidate = int(table[currHash])
670 table[m2Hash] = uint32(s - 2)
671 table[currHash] = uint32(s)
672 if uint32(x>>16) != load32(src, candidate) {
673 cv = load64(src, s+1)
674 s++
675 break
676 }
677 }
678 }
679
680emitRemainder:
681 if nextEmit < len(src) {
682 // Bail if we exceed the maximum size.
683 if d+len(src)-nextEmit > dstLimit {
684 return 0
685 }
686 d += emitLiteralSize(src[nextEmit:])
687 }
688 return d
689}
690
691// emitLiteral writes a literal chunk and returns the number of bytes written.
692//
693// It assumes that:
694//
695// dst is long enough to hold the encoded bytes
696// 0 <= len(lit) && len(lit) <= math.MaxUint32
697func emitLiteralSize(lit []byte) int {
698 if len(lit) == 0 {
699 return 0
700 }
701 switch {
702 case len(lit) <= 60:
703 return len(lit) + 1
704 case len(lit) <= 1<<8:
705 return len(lit) + 2
706 case len(lit) <= 1<<16:
707 return len(lit) + 3
708 case len(lit) <= 1<<24:
709 return len(lit) + 4
710 default:
711 return len(lit) + 5
712 }
713}
714
715func cvtLZ4BlockAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
716 panic("cvtLZ4BlockAsm should be unreachable")
717}
718
719func cvtLZ4BlockSnappyAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
720 panic("cvtLZ4BlockSnappyAsm should be unreachable")
721}
722
723func cvtLZ4sBlockAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
724 panic("cvtLZ4sBlockAsm should be unreachable")
725}
726
727func cvtLZ4sBlockSnappyAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
728 panic("cvtLZ4sBlockSnappyAsm should be unreachable")
729}
generated by cgit v1.2.3 (git 2.45.2) at 2024-11-18 20:59:33 +0000