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Update dependencies (#2007)

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* Update dependencies
This commit is contained in:
Wim
2023-03-09 22:48:00 +01:00
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parent d5f9cdf912
commit 08779c2909
345 changed files with 151040 additions and 125983 deletions
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vendor/github.com/klauspost/compress/s2/README.md generated vendored
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@ -20,11 +20,12 @@ This is important, so you don't have to worry about spending CPU cycles on alrea
* Concurrent stream compression
* Faster decompression, even for Snappy compatible content
* Concurrent Snappy/S2 stream decompression
* Ability to quickly skip forward in compressed stream
* Skip forward in compressed stream
* Random seeking with indexes
* Compatible with reading Snappy compressed content
* Smaller block size overhead on incompressible blocks
* Block concatenation
* Block Dictionary support
* Uncompressed stream mode
* Automatic stream size padding
* Snappy compatible block compression
@ -325,35 +326,35 @@ The content compressed in this mode is fully compatible with the standard decode
Snappy vs S2 **compression** speed on 16 core (32 thread) computer, using all threads and a single thread (1 CPU):
| File | S2 speed | S2 Throughput | S2 % smaller | S2 "better" | "better" throughput | "better" % smaller |
|-----------------------------------------------------------------------------------------------------|----------|---------------|--------------|-------------|---------------------|--------------------|
| [rawstudio-mint14.tar](https://files.klauspost.com/compress/rawstudio-mint14.7z) | 12.70x | 10556 MB/s | 7.35% | 4.15x | 3455 MB/s | 12.79% |
| (1 CPU) | 1.14x | 948 MB/s | - | 0.42x | 349 MB/s | - |
| [github-june-2days-2019.json](https://files.klauspost.com/compress/github-june-2days-2019.json.zst) | 17.13x | 14484 MB/s | 31.60% | 10.09x | 8533 MB/s | 37.71% |
| (1 CPU) | 1.33x | 1127 MB/s | - | 0.70x | 589 MB/s | - |
| [github-ranks-backup.bin](https://files.klauspost.com/compress/github-ranks-backup.bin.zst) | 15.14x | 12000 MB/s | -5.79% | 6.59x | 5223 MB/s | 5.80% |
| (1 CPU) | 1.11x | 877 MB/s | - | 0.47x | 370 MB/s | - |
| [consensus.db.10gb](https://files.klauspost.com/compress/consensus.db.10gb.zst) | 14.62x | 12116 MB/s | 15.90% | 5.35x | 4430 MB/s | 16.08% |
| (1 CPU) | 1.38x | 1146 MB/s | - | 0.38x | 312 MB/s | - |
| [adresser.json](https://files.klauspost.com/compress/adresser.json.zst) | 8.83x | 17579 MB/s | 43.86% | 6.54x | 13011 MB/s | 47.23% |
| (1 CPU) | 1.14x | 2259 MB/s | - | 0.74x | 1475 MB/s | - |
| [gob-stream](https://files.klauspost.com/compress/gob-stream.7z) | 16.72x | 14019 MB/s | 24.02% | 10.11x | 8477 MB/s | 30.48% |
| (1 CPU) | 1.24x | 1043 MB/s | - | 0.70x | 586 MB/s | - |
| [10gb.tar](http://mattmahoney.net/dc/10gb.html) | 13.33x | 9254 MB/s | 1.84% | 6.75x | 4686 MB/s | 6.72% |
| (1 CPU) | 0.97x | 672 MB/s | - | 0.53x | 366 MB/s | - |
| sharnd.out.2gb | 2.11x | 12639 MB/s | 0.01% | 1.98x | 11833 MB/s | 0.01% |
| (1 CPU) | 0.93x | 5594 MB/s | - | 1.34x | 8030 MB/s | - |
| [enwik9](http://mattmahoney.net/dc/textdata.html) | 19.34x | 8220 MB/s | 3.98% | 7.87x | 3345 MB/s | 15.82% |
| (1 CPU) | 1.06x | 452 MB/s | - | 0.50x | 213 MB/s | - |
| [silesia.tar](http://sun.aei.polsl.pl/~sdeor/corpus/silesia.zip) | 10.48x | 6124 MB/s | 5.67% | 3.76x | 2197 MB/s | 12.60% |
| (1 CPU) | 0.97x | 568 MB/s | - | 0.46x | 271 MB/s | - |
| [enwik10](https://encode.su/threads/3315-enwik10-benchmark-results) | 21.07x | 9020 MB/s | 6.36% | 6.91x | 2959 MB/s | 16.95% |
| (1 CPU) | 1.07x | 460 MB/s | - | 0.51x | 220 MB/s | - |
| File | S2 Speed | S2 Throughput | S2 % smaller | S2 "better" | "better" throughput | "better" % smaller |
|---------------------------------------------------------------------------------------------------------|----------|---------------|--------------|-------------|---------------------|--------------------|
| [rawstudio-mint14.tar](https://files.klauspost.com/compress/rawstudio-mint14.7z) | 16.33x | 10556 MB/s | 8.0% | 6.04x | 5252 MB/s | 14.7% |
| (1 CPU) | 1.08x | 940 MB/s | - | 0.46x | 400 MB/s | - |
| [github-june-2days-2019.json](https://files.klauspost.com/compress/github-june-2days-2019.json.zst) | 16.51x | 15224 MB/s | 31.70% | 9.47x | 8734 MB/s | 37.71% |
| (1 CPU) | 1.26x | 1157 MB/s | - | 0.60x | 556 MB/s | - |
| [github-ranks-backup.bin](https://files.klauspost.com/compress/github-ranks-backup.bin.zst) | 15.14x | 12598 MB/s | -5.76% | 6.23x | 5675 MB/s | 3.62% |
| (1 CPU) | 1.02x | 932 MB/s | - | 0.47x | 432 MB/s | - |
| [consensus.db.10gb](https://files.klauspost.com/compress/consensus.db.10gb.zst) | 11.21x | 12116 MB/s | 15.95% | 3.24x | 3500 MB/s | 18.00% |
| (1 CPU) | 1.05x | 1135 MB/s | - | 0.27x | 292 MB/s | - |
| [apache.log](https://files.klauspost.com/compress/apache.log.zst) | 8.55x | 16673 MB/s | 20.54% | 5.85x | 11420 MB/s | 24.97% |
| (1 CPU) | 1.91x | 1771 MB/s | - | 0.53x | 1041 MB/s | - |
| [gob-stream](https://files.klauspost.com/compress/gob-stream.7z) | 15.76x | 14357 MB/s | 24.01% | 8.67x | 7891 MB/s | 33.68% |
| (1 CPU) | 1.17x | 1064 MB/s | - | 0.65x | 595 MB/s | - |
| [10gb.tar](http://mattmahoney.net/dc/10gb.html) | 13.33x | 9835 MB/s | 2.34% | 6.85x | 4863 MB/s | 9.96% |
| (1 CPU) | 0.97x | 689 MB/s | - | 0.55x | 387 MB/s | - |
| sharnd.out.2gb | 9.11x | 13213 MB/s | 0.01% | 1.49x | 9184 MB/s | 0.01% |
| (1 CPU) | 0.88x | 5418 MB/s | - | 0.77x | 5417 MB/s | - |
| [sofia-air-quality-dataset csv](https://files.klauspost.com/compress/sofia-air-quality-dataset.tar.zst) | 22.00x | 11477 MB/s | 18.73% | 11.15x | 5817 MB/s | 27.88% |
| (1 CPU) | 1.23x | 642 MB/s | - | 0.71x | 642 MB/s | - |
| [silesia.tar](http://sun.aei.polsl.pl/~sdeor/corpus/silesia.zip) | 11.23x | 6520 MB/s | 5.9% | 5.35x | 3109 MB/s | 15.88% |
| (1 CPU) | 1.05x | 607 MB/s | - | 0.52x | 304 MB/s | - |
| [enwik9](https://files.klauspost.com/compress/enwik9.zst) | 19.28x | 8440 MB/s | 4.04% | 9.31x | 4076 MB/s | 18.04% |
| (1 CPU) | 1.12x | 488 MB/s | - | 0.57x | 250 MB/s | - |
### Legend
* `S2 speed`: Speed of S2 compared to Snappy, using 16 cores and 1 core.
* `S2 throughput`: Throughput of S2 in MB/s.
* `S2 Speed`: Speed of S2 compared to Snappy, using 16 cores and 1 core.
* `S2 Throughput`: Throughput of S2 in MB/s.
* `S2 % smaller`: How many percent of the Snappy output size is S2 better.
* `S2 "better"`: Speed when enabling "better" compression mode in S2 compared to Snappy.
* `"better" throughput`: Speed when enabling "better" compression mode in S2 compared to Snappy.
@ -361,7 +362,7 @@ Snappy vs S2 **compression** speed on 16 core (32 thread) computer, using all th
There is a good speedup across the board when using a single thread and a significant speedup when using multiple threads.
Machine generated data gets by far the biggest compression boost, with size being being reduced by up to 45% of Snappy size.
Machine generated data gets by far the biggest compression boost, with size being reduced by up to 35% of Snappy size.
The "better" compression mode sees a good improvement in all cases, but usually at a performance cost.
@ -404,15 +405,15 @@ The "better" compression mode will actively look for shorter matches, which is w
Without assembly decompression is also very fast; single goroutine decompression speed. No assembly:
| File | S2 Throughput | S2 throughput |
|--------------------------------|--------------|---------------|
| consensus.db.10gb.s2 | 1.84x | 2289.8 MB/s |
| 10gb.tar.s2 | 1.30x | 867.07 MB/s |
| rawstudio-mint14.tar.s2 | 1.66x | 1329.65 MB/s |
| github-june-2days-2019.json.s2 | 2.36x | 1831.59 MB/s |
| github-ranks-backup.bin.s2 | 1.73x | 1390.7 MB/s |
| enwik9.s2 | 1.67x | 681.53 MB/s |
| adresser.json.s2 | 3.41x | 4230.53 MB/s |
| silesia.tar.s2 | 1.52x | 811.58 |
|--------------------------------|---------------|---------------|
| consensus.db.10gb.s2 | 1.84x | 2289.8 MB/s |
| 10gb.tar.s2 | 1.30x | 867.07 MB/s |
| rawstudio-mint14.tar.s2 | 1.66x | 1329.65 MB/s |
| github-june-2days-2019.json.s2 | 2.36x | 1831.59 MB/s |
| github-ranks-backup.bin.s2 | 1.73x | 1390.7 MB/s |
| enwik9.s2 | 1.67x | 681.53 MB/s |
| adresser.json.s2 | 3.41x | 4230.53 MB/s |
| silesia.tar.s2 | 1.52x | 811.58 |
Even though S2 typically compresses better than Snappy, decompression speed is always better.
@ -450,14 +451,14 @@ The most reliable is a wide dataset.
For this we use [`webdevdata.org-2015-01-07-subset`](https://files.klauspost.com/compress/webdevdata.org-2015-01-07-4GB-subset.7z),
53927 files, total input size: 4,014,735,833 bytes. Single goroutine used.
| * | Input | Output | Reduction | MB/s |
|-------------------|------------|------------|-----------|--------|
| S2 | 4014735833 | 1059723369 | 73.60% | **934.34** |
| S2 Better | 4014735833 | 969670507 | 75.85% | 532.70 |
| S2 Best | 4014735833 | 906625668 | **77.85%** | 46.84 |
| Snappy | 4014735833 | 1128706759 | 71.89% | 762.59 |
| S2, Snappy Output | 4014735833 | 1093821420 | 72.75% | 908.60 |
| LZ4 | 4014735833 | 1079259294 | 73.12% | 526.94 |
| * | Input | Output | Reduction | MB/s |
|-------------------|------------|------------|------------|------------|
| S2 | 4014735833 | 1059723369 | 73.60% | **936.73** |
| S2 Better | 4014735833 | 961580539 | 76.05% | 451.10 |
| S2 Best | 4014735833 | 899182886 | **77.60%** | 46.84 |
| Snappy | 4014735833 | 1128706759 | 71.89% | 790.15 |
| S2, Snappy Output | 4014735833 | 1093823291 | 72.75% | 936.60 |
| LZ4 | 4014735833 | 1063768713 | 73.50% | 452.02 |
S2 delivers both the best single threaded throughput with regular mode and the best compression rate with "best".
"Better" mode provides the same compression speed as LZ4 with better compression ratio.
@ -489,43 +490,24 @@ AMD64 assembly is use for both S2 and Snappy.
| Absolute Perf | Snappy size | S2 Size | Snappy Speed | S2 Speed | Snappy dec | S2 dec |
|-----------------------|-------------|---------|--------------|-------------|-------------|-------------|
| html | 22843 | 21111 | 16246 MB/s | 17438 MB/s | 40972 MB/s | 49263 MB/s |
| urls.10K | 335492 | 287326 | 7943 MB/s | 9693 MB/s | 22523 MB/s | 26484 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 273889 MB/s | 718321 MB/s | 827552 MB/s |
| fireworks.jpeg (200B) | 146 | 155 | 8869 MB/s | 17773 MB/s | 33691 MB/s | 52421 MB/s |
| paper-100k.pdf | 85304 | 84459 | 167546 MB/s | 101263 MB/s | 326905 MB/s | 291944 MB/s |
| html_x_4 | 92234 | 21113 | 15194 MB/s | 50670 MB/s | 30843 MB/s | 32217 MB/s |
| alice29.txt | 88034 | 85975 | 5936 MB/s | 6139 MB/s | 12882 MB/s | 20044 MB/s |
| asyoulik.txt | 77503 | 79650 | 5517 MB/s | 6366 MB/s | 12735 MB/s | 22806 MB/s |
| lcet10.txt | 234661 | 220670 | 6235 MB/s | 6067 MB/s | 14519 MB/s | 18697 MB/s |
| plrabn12.txt | 319267 | 317985 | 5159 MB/s | 5726 MB/s | 11923 MB/s | 19901 MB/s |
| geo.protodata | 23335 | 18690 | 21220 MB/s | 26529 MB/s | 56271 MB/s | 62540 MB/s |
| kppkn.gtb | 69526 | 65312 | 9732 MB/s | 8559 MB/s | 18491 MB/s | 18969 MB/s |
| alice29.txt (128B) | 80 | 82 | 6691 MB/s | 15489 MB/s | 31883 MB/s | 38874 MB/s |
| alice29.txt (1000B) | 774 | 774 | 12204 MB/s | 13000 MB/s | 48056 MB/s | 52341 MB/s |
| alice29.txt (10000B) | 6648 | 6933 | 10044 MB/s | 12806 MB/s | 32378 MB/s | 46322 MB/s |
| alice29.txt (20000B) | 12686 | 13574 | 7733 MB/s | 11210 MB/s | 30566 MB/s | 58969 MB/s |
| html | 22843 | 20868 | 16246 MB/s | 18617 MB/s | 40972 MB/s | 49263 MB/s |
| urls.10K | 335492 | 286541 | 7943 MB/s | 10201 MB/s | 22523 MB/s | 26484 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 303228 MB/s | 718321 MB/s | 827552 MB/s |
| fireworks.jpeg (200B) | 146 | 155 | 8869 MB/s | 20180 MB/s | 33691 MB/s | 52421 MB/s |
| paper-100k.pdf | 85304 | 84202 | 167546 MB/s | 112988 MB/s | 326905 MB/s | 291944 MB/s |
| html_x_4 | 92234 | 20870 | 15194 MB/s | 54457 MB/s | 30843 MB/s | 32217 MB/s |
| alice29.txt | 88034 | 85934 | 5936 MB/s | 6540 MB/s | 12882 MB/s | 20044 MB/s |
| asyoulik.txt | 77503 | 79575 | 5517 MB/s | 6657 MB/s | 12735 MB/s | 22806 MB/s |
| lcet10.txt | 234661 | 220383 | 6235 MB/s | 6303 MB/s | 14519 MB/s | 18697 MB/s |
| plrabn12.txt | 319267 | 318196 | 5159 MB/s | 6074 MB/s | 11923 MB/s | 19901 MB/s |
| geo.protodata | 23335 | 18606 | 21220 MB/s | 25432 MB/s | 56271 MB/s | 62540 MB/s |
| kppkn.gtb | 69526 | 65019 | 9732 MB/s | 8905 MB/s | 18491 MB/s | 18969 MB/s |
| alice29.txt (128B) | 80 | 82 | 6691 MB/s | 17179 MB/s | 31883 MB/s | 38874 MB/s |
| alice29.txt (1000B) | 774 | 774 | 12204 MB/s | 13273 MB/s | 48056 MB/s | 52341 MB/s |
| alice29.txt (10000B) | 6648 | 6933 | 10044 MB/s | 12824 MB/s | 32378 MB/s | 46322 MB/s |
| alice29.txt (20000B) | 12686 | 13516 | 7733 MB/s | 12160 MB/s | 30566 MB/s | 58969 MB/s |
| Relative Perf | Snappy size | S2 size improved | S2 Speed | S2 Dec Speed |
|-----------------------|-------------|------------------|----------|--------------|
| html | 22.31% | 7.58% | 1.07x | 1.20x |
| urls.10K | 47.78% | 14.36% | 1.22x | 1.18x |
| fireworks.jpeg | 99.95% | -0.05% | 0.78x | 1.15x |
| fireworks.jpeg (200B) | 73.00% | -6.16% | 2.00x | 1.56x |
| paper-100k.pdf | 83.30% | 0.99% | 0.60x | 0.89x |
| html_x_4 | 22.52% | 77.11% | 3.33x | 1.04x |
| alice29.txt | 57.88% | 2.34% | 1.03x | 1.56x |
| asyoulik.txt | 61.91% | -2.77% | 1.15x | 1.79x |
| lcet10.txt | 54.99% | 5.96% | 0.97x | 1.29x |
| plrabn12.txt | 66.26% | 0.40% | 1.11x | 1.67x |
| geo.protodata | 19.68% | 19.91% | 1.25x | 1.11x |
| kppkn.gtb | 37.72% | 6.06% | 0.88x | 1.03x |
| alice29.txt (128B) | 62.50% | -2.50% | 2.31x | 1.22x |
| alice29.txt (1000B) | 77.40% | 0.00% | 1.07x | 1.09x |
| alice29.txt (10000B) | 66.48% | -4.29% | 1.27x | 1.43x |
| alice29.txt (20000B) | 63.43% | -7.00% | 1.45x | 1.93x |
Speed is generally at or above Snappy. Small blocks gets a significant speedup, although at the expense of size.
Decompression speed is better than Snappy, except in one case.
@ -543,43 +525,24 @@ So individual benchmarks should only be seen as a guideline and the overall pict
| Absolute Perf | Snappy size | Better Size | Snappy Speed | Better Speed | Snappy dec | Better dec |
|-----------------------|-------------|-------------|--------------|--------------|-------------|-------------|
| html | 22843 | 19833 | 16246 MB/s | 7731 MB/s | 40972 MB/s | 40292 MB/s |
| urls.10K | 335492 | 253529 | 7943 MB/s | 3980 MB/s | 22523 MB/s | 20981 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 9760 MB/s | 718321 MB/s | 823698 MB/s |
| fireworks.jpeg (200B) | 146 | 142 | 8869 MB/s | 594 MB/s | 33691 MB/s | 30101 MB/s |
| paper-100k.pdf | 85304 | 82915 | 167546 MB/s | 7470 MB/s | 326905 MB/s | 198869 MB/s |
| html_x_4 | 92234 | 19841 | 15194 MB/s | 23403 MB/s | 30843 MB/s | 30937 MB/s |
| alice29.txt | 88034 | 73218 | 5936 MB/s | 2945 MB/s | 12882 MB/s | 16611 MB/s |
| asyoulik.txt | 77503 | 66844 | 5517 MB/s | 2739 MB/s | 12735 MB/s | 14975 MB/s |
| lcet10.txt | 234661 | 190589 | 6235 MB/s | 3099 MB/s | 14519 MB/s | 16634 MB/s |
| plrabn12.txt | 319267 | 270828 | 5159 MB/s | 2600 MB/s | 11923 MB/s | 13382 MB/s |
| geo.protodata | 23335 | 18278 | 21220 MB/s | 11208 MB/s | 56271 MB/s | 57961 MB/s |
| kppkn.gtb | 69526 | 61851 | 9732 MB/s | 4556 MB/s | 18491 MB/s | 16524 MB/s |
| alice29.txt (128B) | 80 | 81 | 6691 MB/s | 529 MB/s | 31883 MB/s | 34225 MB/s |
| alice29.txt (1000B) | 774 | 748 | 12204 MB/s | 1943 MB/s | 48056 MB/s | 42068 MB/s |
| alice29.txt (10000B) | 6648 | 6234 | 10044 MB/s | 2949 MB/s | 32378 MB/s | 28813 MB/s |
| alice29.txt (20000B) | 12686 | 11584 | 7733 MB/s | 2822 MB/s | 30566 MB/s | 27315 MB/s |
| html | 22843 | 18972 | 16246 MB/s | 8621 MB/s | 40972 MB/s | 40292 MB/s |
| urls.10K | 335492 | 248079 | 7943 MB/s | 5104 MB/s | 22523 MB/s | 20981 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 84429 MB/s | 718321 MB/s | 823698 MB/s |
| fireworks.jpeg (200B) | 146 | 149 | 8869 MB/s | 7125 MB/s | 33691 MB/s | 30101 MB/s |
| paper-100k.pdf | 85304 | 82887 | 167546 MB/s | 11087 MB/s | 326905 MB/s | 198869 MB/s |
| html_x_4 | 92234 | 18982 | 15194 MB/s | 29316 MB/s | 30843 MB/s | 30937 MB/s |
| alice29.txt | 88034 | 71611 | 5936 MB/s | 3709 MB/s | 12882 MB/s | 16611 MB/s |
| asyoulik.txt | 77503 | 65941 | 5517 MB/s | 3380 MB/s | 12735 MB/s | 14975 MB/s |
| lcet10.txt | 234661 | 184939 | 6235 MB/s | 3537 MB/s | 14519 MB/s | 16634 MB/s |
| plrabn12.txt | 319267 | 264990 | 5159 MB/s | 2960 MB/s | 11923 MB/s | 13382 MB/s |
| geo.protodata | 23335 | 17689 | 21220 MB/s | 10859 MB/s | 56271 MB/s | 57961 MB/s |
| kppkn.gtb | 69526 | 55398 | 9732 MB/s | 5206 MB/s | 18491 MB/s | 16524 MB/s |
| alice29.txt (128B) | 80 | 78 | 6691 MB/s | 7422 MB/s | 31883 MB/s | 34225 MB/s |
| alice29.txt (1000B) | 774 | 746 | 12204 MB/s | 5734 MB/s | 48056 MB/s | 42068 MB/s |
| alice29.txt (10000B) | 6648 | 6218 | 10044 MB/s | 6055 MB/s | 32378 MB/s | 28813 MB/s |
| alice29.txt (20000B) | 12686 | 11492 | 7733 MB/s | 3143 MB/s | 30566 MB/s | 27315 MB/s |
| Relative Perf | Snappy size | Better size | Better Speed | Better dec |
|-----------------------|-------------|-------------|--------------|------------|
| html | 22.31% | 13.18% | 0.48x | 0.98x |
| urls.10K | 47.78% | 24.43% | 0.50x | 0.93x |
| fireworks.jpeg | 99.95% | -0.05% | 0.03x | 1.15x |
| fireworks.jpeg (200B) | 73.00% | 2.74% | 0.07x | 0.89x |
| paper-100k.pdf | 83.30% | 2.80% | 0.07x | 0.61x |
| html_x_4 | 22.52% | 78.49% | 0.04x | 1.00x |
| alice29.txt | 57.88% | 16.83% | 1.54x | 1.29x |
| asyoulik.txt | 61.91% | 13.75% | 0.50x | 1.18x |
| lcet10.txt | 54.99% | 18.78% | 0.50x | 1.15x |
| plrabn12.txt | 66.26% | 15.17% | 0.50x | 1.12x |
| geo.protodata | 19.68% | 21.67% | 0.50x | 1.03x |
| kppkn.gtb | 37.72% | 11.04% | 0.53x | 0.89x |
| alice29.txt (128B) | 62.50% | -1.25% | 0.47x | 1.07x |
| alice29.txt (1000B) | 77.40% | 3.36% | 0.08x | 0.88x |
| alice29.txt (10000B) | 66.48% | 6.23% | 0.16x | 0.89x |
| alice29.txt (20000B) | 63.43% | 8.69% | 0.29x | 0.89x |
Except for the mostly incompressible JPEG image compression is better and usually in the
double digits in terms of percentage reduction over Snappy.
@ -605,33 +568,150 @@ Some examples compared on 16 core CPU, amd64 assembly used:
```
* enwik10
Default... 10000000000 -> 4761467548 [47.61%]; 1.098s, 8685.6MB/s
Better... 10000000000 -> 4219438251 [42.19%]; 1.925s, 4954.2MB/s
Best... 10000000000 -> 3627364337 [36.27%]; 43.051s, 221.5MB/s
Default... 10000000000 -> 4759950115 [47.60%]; 1.03s, 9263.0MB/s
Better... 10000000000 -> 4084706676 [40.85%]; 2.16s, 4415.4MB/s
Best... 10000000000 -> 3615520079 [36.16%]; 42.259s, 225.7MB/s
* github-june-2days-2019.json
Default... 6273951764 -> 1043196283 [16.63%]; 431ms, 13882.3MB/s
Better... 6273951764 -> 949146808 [15.13%]; 547ms, 10938.4MB/s
Best... 6273951764 -> 832855506 [13.27%]; 9.455s, 632.8MB/s
Default... 6273951764 -> 1041700255 [16.60%]; 431ms, 13882.3MB/s
Better... 6273951764 -> 945841238 [15.08%]; 547ms, 10938.4MB/s
Best... 6273951764 -> 826392576 [13.17%]; 9.455s, 632.8MB/s
* nyc-taxi-data-10M.csv
Default... 3325605752 -> 1095998837 [32.96%]; 324ms, 9788.7MB/s
Better... 3325605752 -> 954776589 [28.71%]; 491ms, 6459.4MB/s
Best... 3325605752 -> 779098746 [23.43%]; 8.29s, 382.6MB/s
Default... 3325605752 -> 1093516949 [32.88%]; 324ms, 9788.7MB/s
Better... 3325605752 -> 885394158 [26.62%]; 491ms, 6459.4MB/s
Best... 3325605752 -> 773681257 [23.26%]; 8.29s, 412.0MB/s
* 10gb.tar
Default... 10065157632 -> 5916578242 [58.78%]; 1.028s, 9337.4MB/s
Better... 10065157632 -> 5649207485 [56.13%]; 1.597s, 6010.6MB/s
Best... 10065157632 -> 5208719802 [51.75%]; 32.78s, 292.8MB/
Default... 10065157632 -> 5915541066 [58.77%]; 1.028s, 9337.4MB/s
Better... 10065157632 -> 5453844650 [54.19%]; 1.597s, 4862.7MB/s
Best... 10065157632 -> 5192495021 [51.59%]; 32.78s, 308.2MB/
* consensus.db.10gb
Default... 10737418240 -> 4562648848 [42.49%]; 882ms, 11610.0MB/s
Better... 10737418240 -> 4542428129 [42.30%]; 1.533s, 6679.7MB/s
Best... 10737418240 -> 4244773384 [39.53%]; 42.96s, 238.4MB/s
Default... 10737418240 -> 4549762344 [42.37%]; 882ms, 12118.4MB/s
Better... 10737418240 -> 4438535064 [41.34%]; 1.533s, 3500.9MB/s
Best... 10737418240 -> 4210602774 [39.21%]; 42.96s, 254.4MB/s
```
Decompression speed should be around the same as using the 'better' compression mode.
## Dictionaries
*Note: S2 dictionary compression is currently at an early implementation stage, with no assembly for
neither encoding nor decoding. Performance improvements can be expected in the future.*
Adding dictionaries allow providing a custom dictionary that will serve as lookup in the beginning of blocks.
The same dictionary *must* be used for both encoding and decoding.
S2 does not keep track of whether the same dictionary is used,
and using the wrong dictionary will most often not result in an error when decompressing.
Blocks encoded *without* dictionaries can be decompressed seamlessly *with* a dictionary.
This means it is possible to switch from an encoding without dictionaries to an encoding with dictionaries
and treat the blocks similarly.
Similar to [zStandard dictionaries](https://github.com/facebook/zstd#the-case-for-small-data-compression),
the same usage scenario applies to S2 dictionaries.
> Training works if there is some correlation in a family of small data samples. The more data-specific a dictionary is, the more efficient it is (there is no universal dictionary). Hence, deploying one dictionary per type of data will provide the greatest benefits. Dictionary gains are mostly effective in the first few KB. Then, the compression algorithm will gradually use previously decoded content to better compress the rest of the file.
S2 further limits the dictionary to only be enabled on the first 64KB of a block.
This will remove any negative (speed) impacts of the dictionaries on bigger blocks.
### Compression
Using the [github_users_sample_set](https://github.com/facebook/zstd/releases/download/v1.1.3/github_users_sample_set.tar.zst)
and a 64KB dictionary trained with zStandard the following sizes can be achieved.
| | Default | Better | Best |
|--------------------|------------------|------------------|-----------------------|
| Without Dictionary | 3362023 (44.92%) | 3083163 (41.19%) | 3057944 (40.86%) |
| With Dictionary | 921524 (12.31%) | 873154 (11.67%) | 785503 bytes (10.49%) |
So for highly repetitive content, this case provides an almost 3x reduction in size.
For less uniform data we will use the Go source code tree.
Compressing First 64KB of all `.go` files in `go/src`, Go 1.19.5, 8912 files, 51253563 bytes input:
| | Default | Better | Best |
|--------------------|-------------------|-------------------|-------------------|
| Without Dictionary | 22955767 (44.79%) | 20189613 (39.39% | 19482828 (38.01%) |
| With Dictionary | 19654568 (38.35%) | 16289357 (31.78%) | 15184589 (29.63%) |
| Saving/file | 362 bytes | 428 bytes | 472 bytes |
### Creating Dictionaries
There are no tools to create dictionaries in S2.
However, there are multiple ways to create a useful dictionary:
#### Using a Sample File
If your input is very uniform, you can just use a sample file as the dictionary.
For example in the `github_users_sample_set` above, the average compression only goes up from
10.49% to 11.48% by using the first file as dictionary compared to using a dedicated dictionary.
```Go
// Read a sample
sample, err := os.ReadFile("sample.json")
// Create a dictionary.
dict := s2.MakeDict(sample, nil)
// b := dict.Bytes() will provide a dictionary that can be saved
// and reloaded with s2.NewDict(b).
// To encode:
encoded := dict.Encode(nil, file)
// To decode:
decoded, err := dict.Decode(nil, file)
```
#### Using Zstandard
Zstandard dictionaries can easily be converted to S2 dictionaries.
This can be helpful to generate dictionaries for files that don't have a fixed structure.
Example, with training set files placed in `./training-set`:
`λ zstd -r --train-fastcover training-set/* --maxdict=65536 -o name.dict`
This will create a dictionary of 64KB, that can be converted to a dictionary like this:
```Go
// Decode the Zstandard dictionary.
insp, err := zstd.InspectDictionary(zdict)
if err != nil {
panic(err)
}
// We are only interested in the contents.
// Assume that files start with "// Copyright (c) 2023".
// Search for the longest match for that.
// This may save a few bytes.
dict := s2.MakeDict(insp.Content(), []byte("// Copyright (c) 2023"))
// b := dict.Bytes() will provide a dictionary that can be saved
// and reloaded with s2.NewDict(b).
// We can now encode using this dictionary
encodedWithDict := dict.Encode(nil, payload)
// To decode content:
decoded, err := dict.Decode(nil, encodedWithDict)
```
It is recommended to save the dictionary returned by ` b:= dict.Bytes()`, since that will contain only the S2 dictionary.
This dictionary can later be loaded using `s2.NewDict(b)`. The dictionary then no longer requires `zstd` to be initialized.
Also note how `s2.MakeDict` allows you to search for a common starting sequence of your files.
This can be omitted, at the expense of a few bytes.
# Snappy Compatibility
S2 now offers full compatibility with Snappy.
@ -648,10 +728,10 @@ If you would like more control, you can use the s2 package as described below:
Snappy compatible blocks can be generated with the S2 encoder.
Compression and speed is typically a bit better `MaxEncodedLen` is also smaller for smaller memory usage. Replace
| Snappy | S2 replacement |
|----------------------------|-------------------------|
| snappy.Encode(...) | s2.EncodeSnappy(...) |
| snappy.MaxEncodedLen(...) | s2.MaxEncodedLen(...) |
| Snappy | S2 replacement |
|---------------------------|-----------------------|
| snappy.Encode(...) | s2.EncodeSnappy(...) |
| snappy.MaxEncodedLen(...) | s2.MaxEncodedLen(...) |
`s2.EncodeSnappy` can be replaced with `s2.EncodeSnappyBetter` or `s2.EncodeSnappyBest` to get more efficiently compressed snappy compatible output.
@ -660,12 +740,12 @@ Compression and speed is typically a bit better `MaxEncodedLen` is also smaller
Comparison of [`webdevdata.org-2015-01-07-subset`](https://files.klauspost.com/compress/webdevdata.org-2015-01-07-4GB-subset.7z),
53927 files, total input size: 4,014,735,833 bytes. amd64, single goroutine used:
| Encoder | Size | MB/s | Reduction |
|-----------------------|------------|------------|------------
| snappy.Encode | 1128706759 | 725.59 | 71.89% |
| s2.EncodeSnappy | 1093823291 | **899.16** | 72.75% |
| s2.EncodeSnappyBetter | 1001158548 | 578.49 | 75.06% |
| s2.EncodeSnappyBest | 944507998 | 66.00 | **76.47%**|
| Encoder | Size | MB/s | Reduction |
|-----------------------|------------|------------|------------|
| snappy.Encode | 1128706759 | 725.59 | 71.89% |
| s2.EncodeSnappy | 1093823291 | **899.16** | 72.75% |
| s2.EncodeSnappyBetter | 1001158548 | 578.49 | 75.06% |
| s2.EncodeSnappyBest | 944507998 | 66.00 | **76.47%** |
## Streams
@ -835,6 +915,13 @@ This is done using the regular "Skip" function:
This will ensure that we are at exactly the offset we want, and reading from `dec` will start at the requested offset.
# Compact storage
For compact storage [RemoveIndexHeaders](https://pkg.go.dev/github.com/klauspost/compress/s2#RemoveIndexHeaders) can be used to remove any redundant info from
a serialized index. If you remove the header it must be restored before [Loading](https://pkg.go.dev/github.com/klauspost/compress/s2#Index.Load).
This is expected to save 20 bytes. These can be restored using [RestoreIndexHeaders](https://pkg.go.dev/github.com/klauspost/compress/s2#RestoreIndexHeaders). This removes a layer of security, but is the most compact representation. Returns nil if headers contains errors.
## Index Format:
Each block is structured as a snappy skippable block, with the chunk ID 0x99.
@ -844,20 +931,20 @@ The block can be read from the front, but contains information so it can be read
Numbers are stored as fixed size little endian values or [zigzag encoded](https://developers.google.com/protocol-buffers/docs/encoding#signed_integers) [base 128 varints](https://developers.google.com/protocol-buffers/docs/encoding),
with un-encoded value length of 64 bits, unless other limits are specified.
| Content | Format |
|---------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------|
| ID, `[1]byte` | Always 0x99. |
| Data Length, `[3]byte` | 3 byte little-endian length of the chunk in bytes, following this. |
| Header `[6]byte` | Header, must be `[115, 50, 105, 100, 120, 0]` or in text: "s2idx\x00". |
| UncompressedSize, Varint | Total Uncompressed size. |
| CompressedSize, Varint | Total Compressed size if known. Should be -1 if unknown. |
| EstBlockSize, Varint | Block Size, used for guessing uncompressed offsets. Must be >= 0. |
| Entries, Varint | Number of Entries in index, must be < 65536 and >=0. |
| HasUncompressedOffsets `byte` | 0 if no uncompressed offsets are present, 1 if present. Other values are invalid. |
| UncompressedOffsets, [Entries]VarInt | Uncompressed offsets. See below how to decode. |
| CompressedOffsets, [Entries]VarInt | Compressed offsets. See below how to decode. |
| Block Size, `[4]byte` | Little Endian total encoded size (including header and trailer). Can be used for searching backwards to start of block. |
| Trailer `[6]byte` | Trailer, must be `[0, 120, 100, 105, 50, 115]` or in text: "\x00xdi2s". Can be used for identifying block from end of stream. |
| Content | Format |
|--------------------------------------|-------------------------------------------------------------------------------------------------------------------------------|
| ID, `[1]byte` | Always 0x99. |
| Data Length, `[3]byte` | 3 byte little-endian length of the chunk in bytes, following this. |
| Header `[6]byte` | Header, must be `[115, 50, 105, 100, 120, 0]` or in text: "s2idx\x00". |
| UncompressedSize, Varint | Total Uncompressed size. |
| CompressedSize, Varint | Total Compressed size if known. Should be -1 if unknown. |
| EstBlockSize, Varint | Block Size, used for guessing uncompressed offsets. Must be >= 0. |
| Entries, Varint | Number of Entries in index, must be < 65536 and >=0. |
| HasUncompressedOffsets `byte` | 0 if no uncompressed offsets are present, 1 if present. Other values are invalid. |
| UncompressedOffsets, [Entries]VarInt | Uncompressed offsets. See below how to decode. |
| CompressedOffsets, [Entries]VarInt | Compressed offsets. See below how to decode. |
| Block Size, `[4]byte` | Little Endian total encoded size (including header and trailer). Can be used for searching backwards to start of block. |
| Trailer `[6]byte` | Trailer, must be `[0, 120, 100, 105, 50, 115]` or in text: "\x00xdi2s". Can be used for identifying block from end of stream. |
For regular streams the uncompressed offsets are fully predictable,
so `HasUncompressedOffsets` allows to specify that compressed blocks all have
@ -929,6 +1016,7 @@ To decode from any given uncompressed offset `(wantOffset)`:
See [using indexes](https://github.com/klauspost/compress/tree/master/s2#using-indexes) for functions that perform the operations with a simpler interface.
# Format Extensions
* Frame [Stream identifier](https://github.com/google/snappy/blob/master/framing_format.txt#L68) changed from `sNaPpY` to `S2sTwO`.
@ -951,13 +1039,80 @@ The length is specified by reading the 3-bit length specified in the tag and dec
| 7 | 65540 + read 3 bytes |
This allows any repeat offset + length to be represented by 2 to 5 bytes.
It also allows to emit matches longer than 64 bytes with one copy + one repeat instead of several 64 byte copies.
Lengths are stored as little endian values.
The first copy of a block cannot be a repeat offset and the offset is not carried across blocks in streams.
The first copy of a block cannot be a repeat offset and the offset is reset on every block in streams.
Default streaming block size is 1MB.
# Dictionary Encoding
Adding dictionaries allow providing a custom dictionary that will serve as lookup in the beginning of blocks.
A dictionary provides an initial repeat value that can be used to point to a common header.
Other than that the dictionary contains values that can be used as back-references.
Often used data should be placed at the *end* of the dictionary since offsets < 2048 bytes will be smaller.
## Format
Dictionary *content* must at least 16 bytes and less or equal to 64KiB (65536 bytes).
Encoding: `[repeat value (uvarint)][dictionary content...]`
Before the dictionary content, an unsigned base-128 (uvarint) encoded value specifying the initial repeat offset.
This value is an offset into the dictionary content and not a back-reference offset,
so setting this to 0 will make the repeat value point to the first value of the dictionary.
The value must be less than the dictionary length-8
## Encoding
From the decoder point of view the dictionary content is seen as preceding the encoded content.
`[dictionary content][decoded output]`
Backreferences to the dictionary are encoded as ordinary backreferences that have an offset before the start of the decoded block.
Matches copying from the dictionary are **not** allowed to cross from the dictionary into the decoded data.
However, if a copy ends at the end of the dictionary the next repeat will point to the start of the decoded buffer, which is allowed.
The first match can be a repeat value, which will use the repeat offset stored in the dictionary.
When 64KB (65536 bytes) has been en/decoded it is no longer allowed to reference the dictionary,
neither by a copy nor repeat operations.
If the boundary is crossed while copying from the dictionary, the operation should complete,
but the next instruction is not allowed to reference the dictionary.
Valid blocks encoded *without* a dictionary can be decoded with any dictionary.
There are no checks whether the supplied dictionary is the correct for a block.
Because of this there is no overhead by using a dictionary.
## Example
This is the dictionary content. Elements are separated by `[]`.
Dictionary: `[0x0a][Yesterday 25 bananas were added to Benjamins brown bag]`.
Initial repeat offset is set at 10, which is the letter `2`.
Encoded `[LIT "10"][REPEAT len=10][LIT "hich"][MATCH off=50 len=6][MATCH off=31 len=6][MATCH off=61 len=10]`
Decoded: `[10][ bananas w][hich][ were ][brown ][were added]`
Output: `10 bananas which were brown were added`
## Streams
For streams each block can use the dictionary.
The dictionary cannot not currently be provided on the stream.
# LICENSE
This code is based on the [Snappy-Go](https://github.com/golang/snappy) implementation.

504
vendor/github.com/klauspost/compress/s2/decode.go generated vendored
View File

@ -11,7 +11,9 @@ import (
"fmt"
"io"
"io/ioutil"
"math"
"runtime"
"strconv"
"sync"
)
@ -719,7 +721,11 @@ func (r *Reader) Skip(n int64) error {
// decoded[i:j] contains decoded bytes that have not yet been passed on.
left := int64(r.j - r.i)
if left >= n {
r.i += int(n)
tmp := int64(r.i) + n
if tmp > math.MaxInt32 {
return errors.New("s2: internal overflow in skip")
}
r.i = int(tmp)
return nil
}
n -= int64(r.j - r.i)
@ -875,15 +881,20 @@ func (r *Reader) Skip(n int64) error {
// See Reader.ReadSeeker
type ReadSeeker struct {
*Reader
readAtMu sync.Mutex
}
// ReadSeeker will return an io.ReadSeeker compatible version of the reader.
// ReadSeeker will return an io.ReadSeeker and io.ReaderAt
// compatible version of the reader.
// If 'random' is specified the returned io.Seeker can be used for
// random seeking, otherwise only forward seeking is supported.
// Enabling random seeking requires the original input to support
// the io.Seeker interface.
// A custom index can be specified which will be used if supplied.
// When using a custom index, it will not be read from the input stream.
// The ReadAt position will affect regular reads and the current position of Seek.
// So using Read after ReadAt will continue from where the ReadAt stopped.
// No functions should be used concurrently.
// The returned ReadSeeker contains a shallow reference to the existing Reader,
// meaning changes performed to one is reflected in the other.
func (r *Reader) ReadSeeker(random bool, index []byte) (*ReadSeeker, error) {
@ -947,44 +958,61 @@ func (r *Reader) ReadSeeker(random bool, index []byte) (*ReadSeeker, error) {
// Seek allows seeking in compressed data.
func (r *ReadSeeker) Seek(offset int64, whence int) (int64, error) {
if r.err != nil {
return 0, r.err
}
if offset == 0 && whence == io.SeekCurrent {
return r.blockStart + int64(r.i), nil
}
if !r.readHeader {
// Make sure we read the header.
_, r.err = r.Read([]byte{})
}
rs, ok := r.r.(io.ReadSeeker)
if r.index == nil || !ok {
if whence == io.SeekCurrent && offset >= 0 {
err := r.Skip(offset)
return r.blockStart + int64(r.i), err
if !errors.Is(r.err, io.EOF) {
return 0, r.err
}
if whence == io.SeekStart && offset >= r.blockStart+int64(r.i) {
err := r.Skip(offset - r.blockStart - int64(r.i))
return r.blockStart + int64(r.i), err
}
return 0, ErrUnsupported
// Reset on EOF
r.err = nil
}
}
// Calculate absolute offset.
absOffset := offset
switch whence {
case io.SeekStart:
case io.SeekCurrent:
offset += r.blockStart + int64(r.i)
absOffset = r.blockStart + int64(r.i) + offset
case io.SeekEnd:
if offset > 0 {
return 0, errors.New("seek after end of file")
if r.index == nil {
return 0, ErrUnsupported
}
offset = r.index.TotalUncompressed + offset
absOffset = r.index.TotalUncompressed + offset
default:
r.err = ErrUnsupported
return 0, r.err
}
if offset < 0 {
if absOffset < 0 {
return 0, errors.New("seek before start of file")
}
c, u, err := r.index.Find(offset)
if !r.readHeader {
// Make sure we read the header.
_, r.err = r.Read([]byte{})
if r.err != nil {
return 0, r.err
}
}
// If we are inside current block no need to seek.
// This includes no offset changes.
if absOffset >= r.blockStart && absOffset < r.blockStart+int64(r.j) {
r.i = int(absOffset - r.blockStart)
return r.blockStart + int64(r.i), nil
}
rs, ok := r.r.(io.ReadSeeker)
if r.index == nil || !ok {
currOffset := r.blockStart + int64(r.i)
if absOffset >= currOffset {
err := r.Skip(absOffset - currOffset)
return r.blockStart + int64(r.i), err
}
return 0, ErrUnsupported
}
// We can seek and we have an index.
c, u, err := r.index.Find(absOffset)
if err != nil {
return r.blockStart + int64(r.i), err
}
@ -995,12 +1023,57 @@ func (r *ReadSeeker) Seek(offset int64, whence int) (int64, error) {
return 0, err
}
r.i = r.j // Remove rest of current block.
if u < offset {
r.i = r.j // Remove rest of current block.
r.blockStart = u - int64(r.j) // Adjust current block start for accounting.
if u < absOffset {
// Forward inside block
return offset, r.Skip(offset - u)
return absOffset, r.Skip(absOffset - u)
}
return offset, nil
if u > absOffset {
return 0, fmt.Errorf("s2 seek: (internal error) u (%d) > absOffset (%d)", u, absOffset)
}
return absOffset, nil
}
// ReadAt reads len(p) bytes into p starting at offset off in the
// underlying input source. It returns the number of bytes
// read (0 <= n <= len(p)) and any error encountered.
//
// When ReadAt returns n < len(p), it returns a non-nil error
// explaining why more bytes were not returned. In this respect,
// ReadAt is stricter than Read.
//
// Even if ReadAt returns n < len(p), it may use all of p as scratch
// space during the call. If some data is available but not len(p) bytes,
// ReadAt blocks until either all the data is available or an error occurs.
// In this respect ReadAt is different from Read.
//
// If the n = len(p) bytes returned by ReadAt are at the end of the
// input source, ReadAt may return either err == EOF or err == nil.
//
// If ReadAt is reading from an input source with a seek offset,
// ReadAt should not affect nor be affected by the underlying
// seek offset.
//
// Clients of ReadAt can execute parallel ReadAt calls on the
// same input source. This is however not recommended.
func (r *ReadSeeker) ReadAt(p []byte, offset int64) (int, error) {
r.readAtMu.Lock()
defer r.readAtMu.Unlock()
_, err := r.Seek(offset, io.SeekStart)
if err != nil {
return 0, err
}
n := 0
for n < len(p) {
n2, err := r.Read(p[n:])
if err != nil {
// This will include io.EOF
return n + n2, err
}
n += n2
}
return n, nil
}
// ReadByte satisfies the io.ByteReader interface.
@ -1039,3 +1112,370 @@ func (r *Reader) SkippableCB(id uint8, fn func(r io.Reader) error) error {
r.skippableCB[id] = fn
return nil
}
// s2DecodeDict writes the decoding of src to dst. It assumes that the varint-encoded
// length of the decompressed bytes has already been read, and that len(dst)
// equals that length.
//
// It returns 0 on success or a decodeErrCodeXxx error code on failure.
func s2DecodeDict(dst, src []byte, dict *Dict) int {
if dict == nil {
return s2Decode(dst, src)
}
const debug = false
const debugErrs = debug
if debug {
fmt.Println("Starting decode, dst len:", len(dst))
}
var d, s, length int
offset := len(dict.dict) - dict.repeat
// As long as we can read at least 5 bytes...
for s < len(src)-5 {
// Removing bounds checks is SLOWER, when if doing
// in := src[s:s+5]
// Checked on Go 1.18
switch src[s] & 0x03 {
case tagLiteral:
x := uint32(src[s] >> 2)
switch {
case x < 60:
s++
case x == 60:
s += 2
x = uint32(src[s-1])
case x == 61:
in := src[s : s+3]
x = uint32(in[1]) | uint32(in[2])<<8
s += 3
case x == 62:
in := src[s : s+4]
// Load as 32 bit and shift down.
x = uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24
x >>= 8
s += 4
case x == 63:
in := src[s : s+5]
x = uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24
s += 5
}
length = int(x) + 1
if debug {
fmt.Println("literals, length:", length, "d-after:", d+length)
}
if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
if debugErrs {
fmt.Println("corrupt literal: length:", length, "d-left:", len(dst)-d, "src-left:", len(src)-s)
}
return decodeErrCodeCorrupt
}
copy(dst[d:], src[s:s+length])
d += length
s += length
continue
case tagCopy1:
s += 2
toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1]))
length = int(src[s-2]) >> 2 & 0x7
if toffset == 0 {
if debug {
fmt.Print("(repeat) ")
}
// keep last offset
switch length {
case 5:
length = int(src[s]) + 4
s += 1
case 6:
in := src[s : s+2]
length = int(uint32(in[0])|(uint32(in[1])<<8)) + (1 << 8)
s += 2
case 7:
in := src[s : s+3]
length = int((uint32(in[2])<<16)|(uint32(in[1])<<8)|uint32(in[0])) + (1 << 16)
s += 3
default: // 0-> 4
}
} else {
offset = toffset
}
length += 4
case tagCopy2:
in := src[s : s+3]
offset = int(uint32(in[1]) | uint32(in[2])<<8)
length = 1 + int(in[0])>>2
s += 3
case tagCopy4:
in := src[s : s+5]
offset = int(uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24)
length = 1 + int(in[0])>>2
s += 5
}
if offset <= 0 || length > len(dst)-d {
if debugErrs {
fmt.Println("match error; offset:", offset, "length:", length, "dst-left:", len(dst)-d)
}
return decodeErrCodeCorrupt
}
// copy from dict
if d < offset {
if d > MaxDictSrcOffset {
if debugErrs {
fmt.Println("dict after", MaxDictSrcOffset, "d:", d, "offset:", offset, "length:", length)
}
return decodeErrCodeCorrupt
}
startOff := len(dict.dict) - offset + d
if startOff < 0 || startOff+length > len(dict.dict) {
if debugErrs {
fmt.Printf("offset (%d) + length (%d) bigger than dict (%d)\n", offset, length, len(dict.dict))
}
return decodeErrCodeCorrupt
}
if debug {
fmt.Println("dict copy, length:", length, "offset:", offset, "d-after:", d+length, "dict start offset:", startOff)
}
copy(dst[d:d+length], dict.dict[startOff:])
d += length
continue
}
if debug {
fmt.Println("copy, length:", length, "offset:", offset, "d-after:", d+length)
}
// Copy from an earlier sub-slice of dst to a later sub-slice.
// If no overlap, use the built-in copy:
if offset > length {
copy(dst[d:d+length], dst[d-offset:])
d += length
continue
}
// Unlike the built-in copy function, this byte-by-byte copy always runs
// forwards, even if the slices overlap. Conceptually, this is:
//
// d += forwardCopy(dst[d:d+length], dst[d-offset:])
//
// We align the slices into a and b and show the compiler they are the same size.
// This allows the loop to run without bounds checks.
a := dst[d : d+length]
b := dst[d-offset:]
b = b[:len(a)]
for i := range a {
a[i] = b[i]
}
d += length
}
// Remaining with extra checks...
for s < len(src) {
switch src[s] & 0x03 {
case tagLiteral:
x := uint32(src[s] >> 2)
switch {
case x < 60:
s++
case x == 60:
s += 2
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
x = uint32(src[s-1])
case x == 61:
s += 3
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
x = uint32(src[s-2]) | uint32(src[s-1])<<8
case x == 62:
s += 4
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
x = uint32(src[s-3]) | uint32(src[s-2])<<8 | uint32(src[s-1])<<16
case x == 63:
s += 5
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
x = uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24
}
length = int(x) + 1
if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
if debugErrs {
fmt.Println("corrupt literal: length:", length, "d-left:", len(dst)-d, "src-left:", len(src)-s)
}
return decodeErrCodeCorrupt
}
if debug {
fmt.Println("literals, length:", length, "d-after:", d+length)
}
copy(dst[d:], src[s:s+length])
d += length
s += length
continue
case tagCopy1:
s += 2
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
length = int(src[s-2]) >> 2 & 0x7
toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1]))
if toffset == 0 {
if debug {
fmt.Print("(repeat) ")
}
// keep last offset
switch length {
case 5:
s += 1
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
length = int(uint32(src[s-1])) + 4
case 6:
s += 2
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
length = int(uint32(src[s-2])|(uint32(src[s-1])<<8)) + (1 << 8)
case 7:
s += 3
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
length = int(uint32(src[s-3])|(uint32(src[s-2])<<8)|(uint32(src[s-1])<<16)) + (1 << 16)
default: // 0-> 4
}
} else {
offset = toffset
}
length += 4
case tagCopy2:
s += 3
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
length = 1 + int(src[s-3])>>2
offset = int(uint32(src[s-2]) | uint32(src[s-1])<<8)
case tagCopy4:
s += 5
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
if debugErrs {
fmt.Println("src went oob")
}
return decodeErrCodeCorrupt
}
length = 1 + int(src[s-5])>>2
offset = int(uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24)
}
if offset <= 0 || length > len(dst)-d {
if debugErrs {
fmt.Println("match error; offset:", offset, "length:", length, "dst-left:", len(dst)-d)
}
return decodeErrCodeCorrupt
}
// copy from dict
if d < offset {
if d > MaxDictSrcOffset {
if debugErrs {
fmt.Println("dict after", MaxDictSrcOffset, "d:", d, "offset:", offset, "length:", length)
}
return decodeErrCodeCorrupt
}
rOff := len(dict.dict) - (offset - d)
if debug {
fmt.Println("starting dict entry from dict offset", len(dict.dict)-rOff)
}
if rOff+length > len(dict.dict) {
if debugErrs {
fmt.Println("err: END offset", rOff+length, "bigger than dict", len(dict.dict), "dict offset:", rOff, "length:", length)
}
return decodeErrCodeCorrupt
}
if rOff < 0 {
if debugErrs {
fmt.Println("err: START offset", rOff, "less than 0", len(dict.dict), "dict offset:", rOff, "length:", length)
}
return decodeErrCodeCorrupt
}
copy(dst[d:d+length], dict.dict[rOff:])
d += length
continue
}
if debug {
fmt.Println("copy, length:", length, "offset:", offset, "d-after:", d+length)
}
// Copy from an earlier sub-slice of dst to a later sub-slice.
// If no overlap, use the built-in copy:
if offset > length {
copy(dst[d:d+length], dst[d-offset:])
d += length
continue
}
// Unlike the built-in copy function, this byte-by-byte copy always runs
// forwards, even if the slices overlap. Conceptually, this is:
//
// d += forwardCopy(dst[d:d+length], dst[d-offset:])
//
// We align the slices into a and b and show the compiler they are the same size.
// This allows the loop to run without bounds checks.
a := dst[d : d+length]
b := dst[d-offset:]
b = b[:len(a)]
for i := range a {
a[i] = b[i]
}
d += length
}
if d != len(dst) {
if debugErrs {
fmt.Println("wanted length", len(dst), "got", d)
}
return decodeErrCodeCorrupt
}
return 0
}

47
vendor/github.com/klauspost/compress/s2/decode_other.go generated vendored
View File

@ -28,6 +28,9 @@ func s2Decode(dst, src []byte) int {
// As long as we can read at least 5 bytes...
for s < len(src)-5 {
// Removing bounds checks is SLOWER, when if doing
// in := src[s:s+5]
// Checked on Go 1.18
switch src[s] & 0x03 {
case tagLiteral:
x := uint32(src[s] >> 2)
@ -38,17 +41,25 @@ func s2Decode(dst, src []byte) int {
s += 2
x = uint32(src[s-1])
case x == 61:
in := src[s : s+3]
x = uint32(in[1]) | uint32(in[2])<<8
s += 3
x = uint32(src[s-2]) | uint32(src[s-1])<<8
case x == 62:
in := src[s : s+4]
// Load as 32 bit and shift down.
x = uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24
x >>= 8
s += 4
x = uint32(src[s-3]) | uint32(src[s-2])<<8 | uint32(src[s-1])<<16
case x == 63:
in := src[s : s+5]
x = uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24
s += 5
x = uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24
}
length = int(x) + 1
if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
if debug {
fmt.Println("corrupt: lit size", length)
}
return decodeErrCodeCorrupt
}
if debug {
@ -62,8 +73,8 @@ func s2Decode(dst, src []byte) int {
case tagCopy1:
s += 2
length = int(src[s-2]) >> 2 & 0x7
toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1]))
length = int(src[s-2]) >> 2 & 0x7
if toffset == 0 {
if debug {
fmt.Print("(repeat) ")
@ -71,14 +82,16 @@ func s2Decode(dst, src []byte) int {
// keep last offset
switch length {
case 5:
length = int(src[s]) + 4
s += 1
length = int(uint32(src[s-1])) + 4
case 6:
in := src[s : s+2]
length = int(uint32(in[0])|(uint32(in[1])<<8)) + (1 << 8)
s += 2
length = int(uint32(src[s-2])|(uint32(src[s-1])<<8)) + (1 << 8)
case 7:
in := src[s : s+3]
length = int((uint32(in[2])<<16)|(uint32(in[1])<<8)|uint32(in[0])) + (1 << 16)
s += 3
length = int(uint32(src[s-3])|(uint32(src[s-2])<<8)|(uint32(src[s-1])<<16)) + (1 << 16)
default: // 0-> 4
}
} else {
@ -86,17 +99,23 @@ func s2Decode(dst, src []byte) int {
}
length += 4
case tagCopy2:
in := src[s : s+3]
offset = int(uint32(in[1]) | uint32(in[2])<<8)
length = 1 + int(in[0])>>2
s += 3
length = 1 + int(src[s-3])>>2
offset = int(uint32(src[s-2]) | uint32(src[s-1])<<8)
case tagCopy4:
in := src[s : s+5]
offset = int(uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24)
length = 1 + int(in[0])>>2
s += 5
length = 1 + int(src[s-5])>>2
offset = int(uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24)
}
if offset <= 0 || d < offset || length > len(dst)-d {
if debug {
fmt.Println("corrupt: match, length", length, "offset:", offset, "dst avail:", len(dst)-d, "dst pos:", d)
}
return decodeErrCodeCorrupt
}
@ -163,6 +182,9 @@ func s2Decode(dst, src []byte) int {
}
length = int(x) + 1
if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
if debug {
fmt.Println("corrupt: lit size", length)
}
return decodeErrCodeCorrupt
}
if debug {
@ -229,6 +251,9 @@ func s2Decode(dst, src []byte) int {
}
if offset <= 0 || d < offset || length > len(dst)-d {
if debug {
fmt.Println("corrupt: match, length", length, "offset:", offset, "dst avail:", len(dst)-d, "dst pos:", d)
}
return decodeErrCodeCorrupt
}

331
vendor/github.com/klauspost/compress/s2/dict.go generated vendored Normal file
View File

@ -0,0 +1,331 @@
// Copyright (c) 2022+ Klaus Post. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package s2
import (
"bytes"
"encoding/binary"
"sync"
)
const (
// MinDictSize is the minimum dictionary size when repeat has been read.
MinDictSize = 16
// MaxDictSize is the maximum dictionary size when repeat has been read.
MaxDictSize = 65536
// MaxDictSrcOffset is the maximum offset where a dictionary entry can start.
MaxDictSrcOffset = 65535
)
// Dict contains a dictionary that can be used for encoding and decoding s2
type Dict struct {
dict []byte
repeat int // Repeat as index of dict
fast, better, best sync.Once
fastTable *[1 << 14]uint16
betterTableShort *[1 << 14]uint16
betterTableLong *[1 << 17]uint16
bestTableShort *[1 << 16]uint32
bestTableLong *[1 << 19]uint32
}
// NewDict will read a dictionary.
// It will return nil if the dictionary is invalid.
func NewDict(dict []byte) *Dict {
if len(dict) == 0 {
return nil
}
var d Dict
// Repeat is the first value of the dict
r, n := binary.Uvarint(dict)
if n <= 0 {
return nil
}
dict = dict[n:]
d.dict = dict
if cap(d.dict) < len(d.dict)+16 {
d.dict = append(make([]byte, 0, len(d.dict)+16), d.dict...)
}
if len(dict) < MinDictSize || len(dict) > MaxDictSize {
return nil
}
d.repeat = int(r)
if d.repeat > len(dict) {
return nil
}
return &d
}
// Bytes will return a serialized version of the dictionary.
// The output can be sent to NewDict.
func (d *Dict) Bytes() []byte {
dst := make([]byte, binary.MaxVarintLen16+len(d.dict))
return append(dst[:binary.PutUvarint(dst, uint64(d.repeat))], d.dict...)
}
// MakeDict will create a dictionary.
// 'data' must be at least MinDictSize.
// If data is longer than MaxDictSize only the last MaxDictSize bytes will be used.
// If searchStart is set the start repeat value will be set to the last
// match of this content.
// If no matches are found, it will attempt to find shorter matches.
// This content should match the typical start of a block.
// If at least 4 bytes cannot be matched, repeat is set to start of block.
func MakeDict(data []byte, searchStart []byte) *Dict {
if len(data) == 0 {
return nil
}
if len(data) > MaxDictSize {
data = data[len(data)-MaxDictSize:]
}
var d Dict
dict := data
d.dict = dict
if cap(d.dict) < len(d.dict)+16 {
d.dict = append(make([]byte, 0, len(d.dict)+16), d.dict...)
}
if len(dict) < MinDictSize {
return nil
}
// Find the longest match possible, last entry if multiple.
for s := len(searchStart); s > 4; s-- {
if idx := bytes.LastIndex(data, searchStart[:s]); idx >= 0 && idx <= len(data)-8 {
d.repeat = idx
break
}
}
return &d
}
// Encode returns the encoded form of src. The returned slice may be a sub-
// slice of dst if dst was large enough to hold the entire encoded block.
// Otherwise, a newly allocated slice will be returned.
//
// The dst and src must not overlap. It is valid to pass a nil dst.
//
// The blocks will require the same amount of memory to decode as encoding,
// and does not make for concurrent decoding.
// Also note that blocks do not contain CRC information, so corruption may be undetected.
//
// If you need to encode larger amounts of data, consider using
// the streaming interface which gives all of these features.
func (d *Dict) Encode(dst, src []byte) []byte {
if n := MaxEncodedLen(len(src)); n < 0 {
panic(ErrTooLarge)
} else if cap(dst) < n {
dst = make([]byte, n)
} else {
dst = dst[:n]
}
// The block starts with the varint-encoded length of the decompressed bytes.
dstP := binary.PutUvarint(dst, uint64(len(src)))
if len(src) == 0 {
return dst[:dstP]
}
if len(src) < minNonLiteralBlockSize {
dstP += emitLiteral(dst[dstP:], src)
return dst[:dstP]
}
n := encodeBlockDictGo(dst[dstP:], src, d)
if n > 0 {
dstP += n
return dst[:dstP]
}
// Not compressible
dstP += emitLiteral(dst[dstP:], src)
return dst[:dstP]
}
// EncodeBetter returns the encoded form of src. The returned slice may be a sub-
// slice of dst if dst was large enough to hold the entire encoded block.
// Otherwise, a newly allocated slice will be returned.
//
// EncodeBetter compresses better than Encode but typically with a
// 10-40% speed decrease on both compression and decompression.
//
// The dst and src must not overlap. It is valid to pass a nil dst.
//
// The blocks will require the same amount of memory to decode as encoding,
// and does not make for concurrent decoding.
// Also note that blocks do not contain CRC information, so corruption may be undetected.
//
// If you need to encode larger amounts of data, consider using
// the streaming interface which gives all of these features.
func (d *Dict) EncodeBetter(dst, src []byte) []byte {
if n := MaxEncodedLen(len(src)); n < 0 {
panic(ErrTooLarge)
} else if len(dst) < n {
dst = make([]byte, n)
}
// The block starts with the varint-encoded length of the decompressed bytes.
dstP := binary.PutUvarint(dst, uint64(len(src)))
if len(src) == 0 {
return dst[:dstP]
}
if len(src) < minNonLiteralBlockSize {
dstP += emitLiteral(dst[dstP:], src)
return dst[:dstP]
}
n := encodeBlockBetterDict(dst[dstP:], src, d)
if n > 0 {
dstP += n
return dst[:dstP]
}
// Not compressible
dstP += emitLiteral(dst[dstP:], src)
return dst[:dstP]
}
// EncodeBest returns the encoded form of src. The returned slice may be a sub-
// slice of dst if dst was large enough to hold the entire encoded block.
// Otherwise, a newly allocated slice will be returned.
//
// EncodeBest compresses as good as reasonably possible but with a
// big speed decrease.
//
// The dst and src must not overlap. It is valid to pass a nil dst.
//
// The blocks will require the same amount of memory to decode as encoding,
// and does not make for concurrent decoding.
// Also note that blocks do not contain CRC information, so corruption may be undetected.
//
// If you need to encode larger amounts of data, consider using
// the streaming interface which gives all of these features.
func (d *Dict) EncodeBest(dst, src []byte) []byte {
if n := MaxEncodedLen(len(src)); n < 0 {
panic(ErrTooLarge)
} else if len(dst) < n {
dst = make([]byte, n)
}
// The block starts with the varint-encoded length of the decompressed bytes.
dstP := binary.PutUvarint(dst, uint64(len(src)))
if len(src) == 0 {
return dst[:dstP]
}
if len(src) < minNonLiteralBlockSize {
dstP += emitLiteral(dst[dstP:], src)
return dst[:dstP]
}
n := encodeBlockBest(dst[dstP:], src, d)
if n > 0 {
dstP += n
return dst[:dstP]
}
// Not compressible
dstP += emitLiteral(dst[dstP:], src)
return dst[:dstP]
}
// Decode returns the decoded form of src. The returned slice may be a sub-
// slice of dst if dst was large enough to hold the entire decoded block.
// Otherwise, a newly allocated slice will be returned.
//
// The dst and src must not overlap. It is valid to pass a nil dst.
func (d *Dict) Decode(dst, src []byte) ([]byte, error) {
dLen, s, err := decodedLen(src)
if err != nil {
return nil, err
}
if dLen <= cap(dst) {
dst = dst[:dLen]
} else {
dst = make([]byte, dLen)
}
if s2DecodeDict(dst, src[s:], d) != 0 {
return nil, ErrCorrupt
}
return dst, nil
}
func (d *Dict) initFast() {
d.fast.Do(func() {
const (
tableBits = 14
maxTableSize = 1 << tableBits
)
var table [maxTableSize]uint16
// We stop so any entry of length 8 can always be read.
for i := 0; i < len(d.dict)-8-2; i += 3 {
x0 := load64(d.dict, i)
h0 := hash6(x0, tableBits)
h1 := hash6(x0>>8, tableBits)
h2 := hash6(x0>>16, tableBits)
table[h0] = uint16(i)
table[h1] = uint16(i + 1)
table[h2] = uint16(i + 2)
}
d.fastTable = &table
})
}
func (d *Dict) initBetter() {
d.better.Do(func() {
const (
// Long hash matches.
lTableBits = 17
maxLTableSize = 1 << lTableBits
// Short hash matches.
sTableBits = 14
maxSTableSize = 1 << sTableBits
)
var lTable [maxLTableSize]uint16
var sTable [maxSTableSize]uint16
// We stop so any entry of length 8 can always be read.
for i := 0; i < len(d.dict)-8; i++ {
cv := load64(d.dict, i)
lTable[hash7(cv, lTableBits)] = uint16(i)
sTable[hash4(cv, sTableBits)] = uint16(i)
}
d.betterTableShort = &sTable
d.betterTableLong = &lTable
})
}
func (d *Dict) initBest() {
d.best.Do(func() {
const (
// Long hash matches.
lTableBits = 19
maxLTableSize = 1 << lTableBits
// Short hash matches.
sTableBits = 16
maxSTableSize = 1 << sTableBits
)
var lTable [maxLTableSize]uint32
var sTable [maxSTableSize]uint32
// We stop so any entry of length 8 can always be read.
for i := 0; i < len(d.dict)-8; i++ {
cv := load64(d.dict, i)
hashL := hash8(cv, lTableBits)
hashS := hash4(cv, sTableBits)
candidateL := lTable[hashL]
candidateS := sTable[hashS]
lTable[hashL] = uint32(i) | candidateL<<16
sTable[hashS] = uint32(i) | candidateS<<16
}
d.bestTableShort = &sTable
d.bestTableLong = &lTable
})
}

54
vendor/github.com/klauspost/compress/s2/encode.go generated vendored
View File

@ -58,6 +58,32 @@ func Encode(dst, src []byte) []byte {
return dst[:d]
}
// EstimateBlockSize will perform a very fast compression
// without outputting the result and return the compressed output size.
// The function returns -1 if no improvement could be achieved.
// Using actual compression will most often produce better compression than the estimate.
func EstimateBlockSize(src []byte) (d int) {
if len(src) < 6 || int64(len(src)) > 0xffffffff {
return -1
}
if len(src) <= 1024 {
d = calcBlockSizeSmall(src)
} else {
d = calcBlockSize(src)
}
if d == 0 {
return -1
}
// Size of the varint encoded block size.
d += (bits.Len64(uint64(len(src))) + 7) / 7
if d >= len(src) {
return -1
}
return d
}
// EncodeBetter returns the encoded form of src. The returned slice may be a sub-
// slice of dst if dst was large enough to hold the entire encoded block.
// Otherwise, a newly allocated slice will be returned.
@ -132,7 +158,7 @@ func EncodeBest(dst, src []byte) []byte {
d += emitLiteral(dst[d:], src)
return dst[:d]
}
n := encodeBlockBest(dst[d:], src)
n := encodeBlockBest(dst[d:], src, nil)
if n > 0 {
d += n
return dst[:d]
@ -404,10 +430,11 @@ type Writer struct {
buffers sync.Pool
pad int
writer io.Writer
randSrc io.Reader
writerWg sync.WaitGroup
index Index
writer io.Writer
randSrc io.Reader
writerWg sync.WaitGroup
index Index
customEnc func(dst, src []byte) int
// wroteStreamHeader is whether we have written the stream header.
wroteStreamHeader bool
@ -773,6 +800,9 @@ func (w *Writer) EncodeBuffer(buf []byte) (err error) {
}
func (w *Writer) encodeBlock(obuf, uncompressed []byte) int {
if w.customEnc != nil {
return w.customEnc(obuf, uncompressed)
}
if w.snappy {
switch w.level {
case levelFast:
@ -790,7 +820,7 @@ func (w *Writer) encodeBlock(obuf, uncompressed []byte) int {
case levelBetter:
return encodeBlockBetter(obuf, uncompressed)
case levelBest:
return encodeBlockBest(obuf, uncompressed)
return encodeBlockBest(obuf, uncompressed, nil)
}
return 0
}
@ -1339,3 +1369,15 @@ func WriterFlushOnWrite() WriterOption {
return nil
}
}
// WriterCustomEncoder allows to override the encoder for blocks on the stream.
// The function must compress 'src' into 'dst' and return the bytes used in dst as an integer.
// Block size (initial varint) should not be added by the encoder.
// Returning value 0 indicates the block could not be compressed.
// The function should expect to be called concurrently.
func WriterCustomEncoder(fn func(dst, src []byte) int) WriterOption {
return func(w *Writer) error {
w.customEnc = fn
return nil
}
}

595
vendor/github.com/klauspost/compress/s2/encode_all.go generated vendored
View File

@ -8,6 +8,7 @@ package s2
import (
"bytes"
"encoding/binary"
"fmt"
"math/bits"
)
@ -58,8 +59,9 @@ func encodeGo(dst, src []byte) []byte {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockGo(dst, src []byte) (d int) {
// Initialize the hash table.
const (
@ -454,3 +456,594 @@ emitRemainder:
}
return d
}
// encodeBlockGo encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockDictGo(dst, src []byte, dict *Dict) (d int) {
// Initialize the hash table.
const (
tableBits = 14
maxTableSize = 1 << tableBits
maxAhead = 8 // maximum bytes ahead without checking sLimit
debug = false
)
dict.initFast()
var table [maxTableSize]uint32
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := len(src) - inputMargin
if sLimit > MaxDictSrcOffset-maxAhead {
sLimit = MaxDictSrcOffset - maxAhead
}
// Bail if we can't compress to at least this.
dstLimit := len(src) - len(src)>>5 - 5
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := 0
// The encoded form can start with a dict entry (copy or repeat).
s := 0
// Convert dict repeat to offset
repeat := len(dict.dict) - dict.repeat
cv := load64(src, 0)
// While in dict
searchDict:
for {
// Next src position to check
nextS := s + (s-nextEmit)>>6 + 4
hash0 := hash6(cv, tableBits)
hash1 := hash6(cv>>8, tableBits)
if nextS > sLimit {
if debug {
fmt.Println("slimit reached", s, nextS)
}
break searchDict
}
candidateDict := int(dict.fastTable[hash0])
candidateDict2 := int(dict.fastTable[hash1])
candidate2 := int(table[hash1])
candidate := int(table[hash0])
table[hash0] = uint32(s)
table[hash1] = uint32(s + 1)
hash2 := hash6(cv>>16, tableBits)
// Check repeat at offset checkRep.
const checkRep = 1
if repeat > s {
candidate := len(dict.dict) - repeat + s
if repeat-s >= 4 && uint32(cv) == load32(dict.dict, candidate) {
// Extend back
base := s
for i := candidate; base > nextEmit && i > 0 && dict.dict[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if debug && nextEmit != base {
fmt.Println("emitted ", base-nextEmit, "literals")
}
s += 4
candidate += 4
for candidate < len(dict.dict)-8 && s <= len(src)-8 {
if diff := load64(src, s) ^ load64(dict.dict, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitRepeat(dst[d:], repeat, s-base)
if debug {
fmt.Println("emitted dict repeat length", s-base, "offset:", repeat, "s:", s)
}
nextEmit = s
if s >= sLimit {
break searchDict
}
cv = load64(src, s)
continue
}
} else if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if debug && nextEmit != base {
fmt.Println("emitted ", base-nextEmit, "literals")
}
// Extend forward
candidate := s - repeat + 4 + checkRep
s += 4 + checkRep
for s <= sLimit {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
if debug {
// Validate match.
if s <= candidate {
panic("s <= candidate")
}
a := src[base:s]
b := src[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
if nextEmit > 0 {
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
} else {
// First match, cannot be repeat.
d += emitCopy(dst[d:], repeat, s-base)
}
nextEmit = s
if s >= sLimit {
break searchDict
}
if debug {
fmt.Println("emitted reg repeat", s-base, "s:", s)
}
cv = load64(src, s)
continue searchDict
}
if s == 0 {
cv = load64(src, nextS)
s = nextS
continue searchDict
}
// Start with table. These matches will always be closer.
if uint32(cv) == load32(src, candidate) {
goto emitMatch
}
candidate = int(table[hash2])
if uint32(cv>>8) == load32(src, candidate2) {
table[hash2] = uint32(s + 2)
candidate = candidate2
s++
goto emitMatch
}
// Check dict. Dicts have longer offsets, so we want longer matches.
if cv == load64(dict.dict, candidateDict) {
table[hash2] = uint32(s + 2)
goto emitDict
}
candidateDict = int(dict.fastTable[hash2])
// Check if upper 7 bytes match
if candidateDict2 >= 1 {
if cv^load64(dict.dict, candidateDict2-1) < (1 << 8) {
table[hash2] = uint32(s + 2)
candidateDict = candidateDict2
s++
goto emitDict
}
}
table[hash2] = uint32(s + 2)
if uint32(cv>>16) == load32(src, candidate) {
s += 2
goto emitMatch
}
if candidateDict >= 2 {
// Check if upper 6 bytes match
if cv^load64(dict.dict, candidateDict-2) < (1 << 16) {
s += 2
goto emitDict
}
}
cv = load64(src, nextS)
s = nextS
continue searchDict
emitDict:
{
if debug {
if load32(dict.dict, candidateDict) != load32(src, s) {
panic("dict emit mismatch")
}
}
// Extend backwards.
// The top bytes will be rechecked to get the full match.
for candidateDict > 0 && s > nextEmit && dict.dict[candidateDict-1] == src[s-1] {
candidateDict--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
d += emitLiteral(dst[d:], src[nextEmit:s])
if debug && nextEmit != s {
fmt.Println("emitted ", s-nextEmit, "literals")
}
{
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
repeat = s + (len(dict.dict)) - candidateDict
// Extend the 4-byte match as long as possible.
s += 4
candidateDict += 4
for s <= len(src)-8 && len(dict.dict)-candidateDict >= 8 {
if diff := load64(src, s) ^ load64(dict.dict, candidateDict); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidateDict += 8
}
// Matches longer than 64 are split.
if s <= sLimit || s-base < 8 {
d += emitCopy(dst[d:], repeat, s-base)
} else {
// Split to ensure we don't start a copy within next block
d += emitCopy(dst[d:], repeat, 4)
d += emitRepeat(dst[d:], repeat, s-base-4)
}
if false {
// Validate match.
if s <= candidate {
panic("s <= candidate")
}
a := src[base:s]
b := dict.dict[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
if debug {
fmt.Println("emitted dict copy, length", s-base, "offset:", repeat, "s:", s)
}
nextEmit = s
if s >= sLimit {
break searchDict
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Index and continue loop to try new candidate.
x := load64(src, s-2)
m2Hash := hash6(x, tableBits)
currHash := hash6(x>>8, tableBits)
candidate = int(table[currHash])
table[m2Hash] = uint32(s - 2)
table[currHash] = uint32(s - 1)
cv = load64(src, s)
}
continue
}
emitMatch:
// Extend backwards.
// The top bytes will be rechecked to get the full match.
for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
candidate--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
d += emitLiteral(dst[d:], src[nextEmit:s])
if debug && nextEmit != s {
fmt.Println("emitted ", s-nextEmit, "literals")
}
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
repeat = base - candidate
// Extend the 4-byte match as long as possible.
s += 4
candidate += 4
for s <= len(src)-8 {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitCopy(dst[d:], repeat, s-base)
if debug {
// Validate match.
if s <= candidate {
panic("s <= candidate")
}
a := src[base:s]
b := src[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
if debug {
fmt.Println("emitted src copy, length", s-base, "offset:", repeat, "s:", s)
}
nextEmit = s
if s >= sLimit {
break searchDict
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Check for an immediate match, otherwise start search at s+1
x := load64(src, s-2)
m2Hash := hash6(x, tableBits)
currHash := hash6(x>>16, tableBits)
candidate = int(table[currHash])
table[m2Hash] = uint32(s - 2)
table[currHash] = uint32(s)
if debug && s == candidate {
panic("s == candidate")
}
if uint32(x>>16) != load32(src, candidate) {
cv = load64(src, s+1)
s++
break
}
}
}
// Search without dict:
if repeat > s {
repeat = 0
}
// No more dict
sLimit = len(src) - inputMargin
if s >= sLimit {
goto emitRemainder
}
if debug {
fmt.Println("non-dict matching at", s, "repeat:", repeat)
}
cv = load64(src, s)
if debug {
fmt.Println("now", s, "->", sLimit, "out:", d, "left:", len(src)-s, "nextemit:", nextEmit, "dstLimit:", dstLimit, "s:", s)
}
for {
candidate := 0
for {
// Next src position to check
nextS := s + (s-nextEmit)>>6 + 4
if nextS > sLimit {
goto emitRemainder
}
hash0 := hash6(cv, tableBits)
hash1 := hash6(cv>>8, tableBits)
candidate = int(table[hash0])
candidate2 := int(table[hash1])
table[hash0] = uint32(s)
table[hash1] = uint32(s + 1)
hash2 := hash6(cv>>16, tableBits)
// Check repeat at offset checkRep.
const checkRep = 1
if repeat > 0 && uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if debug && nextEmit != base {
fmt.Println("emitted ", base-nextEmit, "literals")
}
// Extend forward
candidate := s - repeat + 4 + checkRep
s += 4 + checkRep
for s <= sLimit {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
if debug {
// Validate match.
if s <= candidate {
panic("s <= candidate")
}
a := src[base:s]
b := src[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
if nextEmit > 0 {
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
} else {
// First match, cannot be repeat.
d += emitCopy(dst[d:], repeat, s-base)
}
if debug {
fmt.Println("emitted src repeat length", s-base, "offset:", repeat, "s:", s)
}
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
cv = load64(src, s)
continue
}
if uint32(cv) == load32(src, candidate) {
break
}
candidate = int(table[hash2])
if uint32(cv>>8) == load32(src, candidate2) {
table[hash2] = uint32(s + 2)
candidate = candidate2
s++
break
}
table[hash2] = uint32(s + 2)
if uint32(cv>>16) == load32(src, candidate) {
s += 2
break
}
cv = load64(src, nextS)
s = nextS
}
// Extend backwards.
// The top bytes will be rechecked to get the full match.
for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
candidate--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
d += emitLiteral(dst[d:], src[nextEmit:s])
if debug && nextEmit != s {
fmt.Println("emitted ", s-nextEmit, "literals")
}
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
repeat = base - candidate
// Extend the 4-byte match as long as possible.
s += 4
candidate += 4
for s <= len(src)-8 {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitCopy(dst[d:], repeat, s-base)
if debug {
// Validate match.
if s <= candidate {
panic("s <= candidate")
}
a := src[base:s]
b := src[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
if debug {
fmt.Println("emitted src copy, length", s-base, "offset:", repeat, "s:", s)
}
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Check for an immediate match, otherwise start search at s+1
x := load64(src, s-2)
m2Hash := hash6(x, tableBits)
currHash := hash6(x>>16, tableBits)
candidate = int(table[currHash])
table[m2Hash] = uint32(s - 2)
table[currHash] = uint32(s)
if debug && s == candidate {
panic("s == candidate")
}
if uint32(x>>16) != load32(src, candidate) {
cv = load64(src, s+1)
s++
break
}
}
}
emitRemainder:
if nextEmit < len(src) {
// Bail if we exceed the maximum size.
if d+len(src)-nextEmit > dstLimit {
return 0
}
d += emitLiteral(dst[d:], src[nextEmit:])
if debug && nextEmit != s {
fmt.Println("emitted ", len(src)-nextEmit, "literals")
}
}
return d
}

14
vendor/github.com/klauspost/compress/s2/encode_amd64.go generated vendored
View File

@ -3,13 +3,16 @@
package s2
const hasAmd64Asm = true
// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlock(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...
@ -43,8 +46,9 @@ func encodeBlock(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetter(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...
@ -78,8 +82,9 @@ func encodeBlockBetter(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockSnappy(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...
@ -112,8 +117,9 @@ func encodeBlockSnappy(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterSnappy(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...

225
vendor/github.com/klauspost/compress/s2/encode_best.go generated vendored
View File

@ -7,6 +7,7 @@ package s2
import (
"fmt"
"math"
"math/bits"
)
@ -15,9 +16,10 @@ import (
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBest(dst, src []byte) (d int) {
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBest(dst, src []byte, dict *Dict) (d int) {
// Initialize the hash tables.
const (
// Long hash matches.
@ -29,6 +31,8 @@ func encodeBlockBest(dst, src []byte) (d int) {
maxSTableSize = 1 << sTableBits
inputMargin = 8 + 2
debug = false
)
// sLimit is when to stop looking for offset/length copies. The inputMargin
@ -38,6 +42,10 @@ func encodeBlockBest(dst, src []byte) (d int) {
if len(src) < minNonLiteralBlockSize {
return 0
}
sLimitDict := len(src) - inputMargin
if sLimitDict > MaxDictSrcOffset-inputMargin {
sLimitDict = MaxDictSrcOffset - inputMargin
}
var lTable [maxLTableSize]uint64
var sTable [maxSTableSize]uint64
@ -51,10 +59,15 @@ func encodeBlockBest(dst, src []byte) (d int) {
// The encoded form must start with a literal, as there are no previous
// bytes to copy, so we start looking for hash matches at s == 1.
s := 1
repeat := 1
if dict != nil {
dict.initBest()
s = 0
repeat = len(dict.dict) - dict.repeat
}
cv := load64(src, s)
// We search for a repeat at -1, but don't output repeats when nextEmit == 0
repeat := 1
const lowbitMask = 0xffffffff
getCur := func(x uint64) int {
return int(x & lowbitMask)
@ -66,11 +79,11 @@ func encodeBlockBest(dst, src []byte) (d int) {
for {
type match struct {
offset int
s int
length int
score int
rep bool
offset int
s int
length int
score int
rep, dict bool
}
var best match
for {
@ -84,6 +97,12 @@ func encodeBlockBest(dst, src []byte) (d int) {
if nextS > sLimit {
goto emitRemainder
}
if dict != nil && s >= MaxDictSrcOffset {
dict = nil
if repeat > s {
repeat = math.MinInt32
}
}
hashL := hash8(cv, lTableBits)
hashS := hash4(cv, sTableBits)
candidateL := lTable[hashL]
@ -113,7 +132,15 @@ func encodeBlockBest(dst, src []byte) (d int) {
}
m := match{offset: offset, s: s, length: 4 + offset, rep: rep}
s += 4
for s <= sLimit {
for s < len(src) {
if len(src)-s < 8 {
if src[s] == src[m.length] {
m.length++
s++
continue
}
break
}
if diff := load64(src, s) ^ load64(src, m.length); diff != 0 {
m.length += bits.TrailingZeros64(diff) >> 3
break
@ -129,6 +156,62 @@ func encodeBlockBest(dst, src []byte) (d int) {
}
return m
}
matchDict := func(candidate, s int, first uint32, rep bool) match {
// Calculate offset as if in continuous array with s
offset := -len(dict.dict) + candidate
if best.length != 0 && best.s-best.offset == s-offset && !rep {
// Don't retest if we have the same offset.
return match{offset: offset, s: s}
}
if load32(dict.dict, candidate) != first {
return match{offset: offset, s: s}
}
m := match{offset: offset, s: s, length: 4 + candidate, rep: rep, dict: true}
s += 4
if !rep {
for s < sLimitDict && m.length < len(dict.dict) {
if len(src)-s < 8 || len(dict.dict)-m.length < 8 {
if src[s] == dict.dict[m.length] {
m.length++
s++
continue
}
break
}
if diff := load64(src, s) ^ load64(dict.dict, m.length); diff != 0 {
m.length += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
m.length += 8
}
} else {
for s < len(src) && m.length < len(dict.dict) {
if len(src)-s < 8 || len(dict.dict)-m.length < 8 {
if src[s] == dict.dict[m.length] {
m.length++
s++
continue
}
break
}
if diff := load64(src, s) ^ load64(dict.dict, m.length); diff != 0 {
m.length += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
m.length += 8
}
}
m.length -= candidate
m.score = score(m)
if m.score <= -m.s {
// Eliminate if no savings, we might find a better one.
m.length = 0
}
return m
}
bestOf := func(a, b match) match {
if b.length == 0 {
@ -145,45 +228,99 @@ func encodeBlockBest(dst, src []byte) (d int) {
return b
}
best = bestOf(matchAt(getCur(candidateL), s, uint32(cv), false), matchAt(getPrev(candidateL), s, uint32(cv), false))
best = bestOf(best, matchAt(getCur(candidateS), s, uint32(cv), false))
best = bestOf(best, matchAt(getPrev(candidateS), s, uint32(cv), false))
if s > 0 {
best = bestOf(matchAt(getCur(candidateL), s, uint32(cv), false), matchAt(getPrev(candidateL), s, uint32(cv), false))
best = bestOf(best, matchAt(getCur(candidateS), s, uint32(cv), false))
best = bestOf(best, matchAt(getPrev(candidateS), s, uint32(cv), false))
}
if dict != nil {
candidateL := dict.bestTableLong[hashL]
candidateS := dict.bestTableShort[hashS]
best = bestOf(best, matchDict(int(candidateL&0xffff), s, uint32(cv), false))
best = bestOf(best, matchDict(int(candidateL>>16), s, uint32(cv), false))
best = bestOf(best, matchDict(int(candidateS&0xffff), s, uint32(cv), false))
best = bestOf(best, matchDict(int(candidateS>>16), s, uint32(cv), false))
}
{
best = bestOf(best, matchAt(s-repeat+1, s+1, uint32(cv>>8), true))
if (dict == nil || repeat <= s) && repeat > 0 {
best = bestOf(best, matchAt(s-repeat+1, s+1, uint32(cv>>8), true))
} else if s-repeat < -4 && dict != nil {
candidate := len(dict.dict) - (repeat - s)
best = bestOf(best, matchDict(candidate, s, uint32(cv), true))
candidate++
best = bestOf(best, matchDict(candidate, s+1, uint32(cv>>8), true))
}
if best.length > 0 {
hashS := hash4(cv>>8, sTableBits)
// s+1
nextShort := sTable[hash4(cv>>8, sTableBits)]
nextShort := sTable[hashS]
s := s + 1
cv := load64(src, s)
nextLong := lTable[hash8(cv, lTableBits)]
hashL := hash8(cv, lTableBits)
nextLong := lTable[hashL]
best = bestOf(best, matchAt(getCur(nextShort), s, uint32(cv), false))
best = bestOf(best, matchAt(getPrev(nextShort), s, uint32(cv), false))
best = bestOf(best, matchAt(getCur(nextLong), s, uint32(cv), false))
best = bestOf(best, matchAt(getPrev(nextLong), s, uint32(cv), false))
// Repeat at + 2
best = bestOf(best, matchAt(s-repeat+1, s+1, uint32(cv>>8), true))
// Dict at + 1
if dict != nil {
candidateL := dict.bestTableLong[hashL]
candidateS := dict.bestTableShort[hashS]
best = bestOf(best, matchDict(int(candidateL&0xffff), s, uint32(cv), false))
best = bestOf(best, matchDict(int(candidateS&0xffff), s, uint32(cv), false))
}
// s+2
if true {
nextShort = sTable[hash4(cv>>8, sTableBits)]
hashS := hash4(cv>>8, sTableBits)
nextShort = sTable[hashS]
s++
cv = load64(src, s)
nextLong = lTable[hash8(cv, lTableBits)]
hashL := hash8(cv, lTableBits)
nextLong = lTable[hashL]
if (dict == nil || repeat <= s) && repeat > 0 {
// Repeat at + 2
best = bestOf(best, matchAt(s-repeat, s, uint32(cv), true))
} else if repeat-s > 4 && dict != nil {
candidate := len(dict.dict) - (repeat - s)
best = bestOf(best, matchDict(candidate, s, uint32(cv), true))
}
best = bestOf(best, matchAt(getCur(nextShort), s, uint32(cv), false))
best = bestOf(best, matchAt(getPrev(nextShort), s, uint32(cv), false))
best = bestOf(best, matchAt(getCur(nextLong), s, uint32(cv), false))
best = bestOf(best, matchAt(getPrev(nextLong), s, uint32(cv), false))
// Dict at +2
// Very small gain
if dict != nil {
candidateL := dict.bestTableLong[hashL]
candidateS := dict.bestTableShort[hashS]
best = bestOf(best, matchDict(int(candidateL&0xffff), s, uint32(cv), false))
best = bestOf(best, matchDict(int(candidateS&0xffff), s, uint32(cv), false))
}
}
// Search for a match at best match end, see if that is better.
if sAt := best.s + best.length; sAt < sLimit {
sBack := best.s
backL := best.length
// Allow some bytes at the beginning to mismatch.
// Sweet spot is around 1-2 bytes, but depends on input.
// The skipped bytes are tested in Extend backwards,
// and still picked up as part of the match if they do.
const skipBeginning = 2
const skipEnd = 1
if sAt := best.s + best.length - skipEnd; sAt < sLimit {
sBack := best.s + skipBeginning - skipEnd
backL := best.length - skipBeginning
// Load initial values
cv = load64(src, sBack)
// Search for mismatch
// Grab candidates...
next := lTable[hash8(load64(src, sAt), lTableBits)]
//next := sTable[hash4(load64(src, sAt), sTableBits)]
if checkAt := getCur(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
@ -191,6 +328,16 @@ func encodeBlockBest(dst, src []byte) (d int) {
if checkAt := getPrev(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
}
// Disabled: Extremely small gain
if false {
next = sTable[hash4(load64(src, sAt), sTableBits)]
if checkAt := getCur(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
}
if checkAt := getPrev(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
}
}
}
}
}
@ -209,7 +356,7 @@ func encodeBlockBest(dst, src []byte) (d int) {
// Extend backwards, not needed for repeats...
s = best.s
if !best.rep {
if !best.rep && !best.dict {
for best.offset > 0 && s > nextEmit && src[best.offset-1] == src[s-1] {
best.offset--
best.length++
@ -226,7 +373,6 @@ func encodeBlockBest(dst, src []byte) (d int) {
base := s
offset := s - best.offset
s += best.length
if offset > 65535 && s-base <= 5 && !best.rep {
@ -238,16 +384,28 @@ func encodeBlockBest(dst, src []byte) (d int) {
cv = load64(src, s)
continue
}
if debug && nextEmit != base {
fmt.Println("EMIT", base-nextEmit, "literals. base-after:", base)
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if best.rep {
if nextEmit > 0 {
if nextEmit > 0 || best.dict {
if debug {
fmt.Println("REPEAT, length", best.length, "offset:", offset, "s-after:", s, "dict:", best.dict, "best:", best)
}
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], offset, best.length)
} else {
// First match, cannot be repeat.
// First match without dict cannot be a repeat.
if debug {
fmt.Println("COPY, length", best.length, "offset:", offset, "s-after:", s, "dict:", best.dict, "best:", best)
}
d += emitCopy(dst[d:], offset, best.length)
}
} else {
if debug {
fmt.Println("COPY, length", best.length, "offset:", offset, "s-after:", s, "dict:", best.dict, "best:", best)
}
d += emitCopy(dst[d:], offset, best.length)
}
repeat = offset
@ -278,6 +436,9 @@ emitRemainder:
if d+len(src)-nextEmit > dstLimit {
return 0
}
if debug && nextEmit != s {
fmt.Println("emitted ", len(src)-nextEmit, "literals")
}
d += emitLiteral(dst[d:], src[nextEmit:])
}
return d
@ -288,8 +449,9 @@ emitRemainder:
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBestSnappy(dst, src []byte) (d int) {
// Initialize the hash tables.
const (
@ -546,6 +708,7 @@ emitRemainder:
// emitCopySize returns the size to encode the offset+length
//
// It assumes that:
//
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
func emitCopySize(offset, length int) int {
@ -584,6 +747,7 @@ func emitCopySize(offset, length int) int {
// emitCopyNoRepeatSize returns the size to encode the offset+length
//
// It assumes that:
//
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
func emitCopyNoRepeatSize(offset, length int) int {
@ -621,7 +785,6 @@ func emitRepeatSize(offset, length int) int {
left := 0
if length > maxRepeat {
left = length - maxRepeat + 4
length = maxRepeat - 4
}
if left > 0 {
return 5 + emitRepeatSize(offset, left)

727
vendor/github.com/klauspost/compress/s2/encode_better.go generated vendored
View File

@ -6,6 +6,8 @@
package s2
import (
"bytes"
"fmt"
"math/bits"
)
@ -42,8 +44,9 @@ func hash8(u uint64, h uint8) uint32 {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterGo(dst, src []byte) (d int) {
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
@ -56,7 +59,7 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
// Initialize the hash tables.
const (
// Long hash matches.
lTableBits = 16
lTableBits = 17
maxLTableSize = 1 << lTableBits
// Short hash matches.
@ -97,9 +100,26 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
lTable[hashL] = uint32(s)
sTable[hashS] = uint32(s)
valLong := load64(src, candidateL)
valShort := load64(src, candidateS)
// If long matches at least 8 bytes, use that.
if cv == valLong {
break
}
if cv == valShort {
candidateL = candidateS
break
}
// Check repeat at offset checkRep.
const checkRep = 1
if false && uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
// Minimum length of a repeat. Tested with various values.
// While 4-5 offers improvements in some, 6 reduces
// regressions significantly.
const wantRepeatBytes = 6
const repeatMask = ((1 << (wantRepeatBytes * 8)) - 1) << (8 * checkRep)
if false && repeat > 0 && cv&repeatMask == load64(src, s-repeat)&repeatMask {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
@ -109,8 +129,8 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
d += emitLiteral(dst[d:], src[nextEmit:base])
// Extend forward
candidate := s - repeat + 4 + checkRep
s += 4 + checkRep
candidate := s - repeat + wantRepeatBytes + checkRep
s += wantRepeatBytes + checkRep
for s < len(src) {
if len(src)-s < 8 {
if src[s] == src[candidate] {
@ -127,28 +147,40 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
s += 8
candidate += 8
}
if nextEmit > 0 {
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
} else {
// First match, cannot be repeat.
d += emitCopy(dst[d:], repeat, s-base)
}
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// Index in-between
index0 := base + 1
index1 := s - 2
cv = load64(src, s)
for index0 < index1 {
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 2
index1 -= 2
}
cv = load64(src, s)
continue
}
if uint32(cv) == load32(src, candidateL) {
// Long likely matches 7, so take that.
if uint32(cv) == uint32(valLong) {
break
}
// Check our short candidate
if uint32(cv) == load32(src, candidateS) {
if uint32(cv) == uint32(valShort) {
// Try a long candidate at s+1
hashL = hash7(cv>>8, lTableBits)
candidateL = int(lTable[hashL])
@ -227,21 +259,29 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
// Do we have space for more, if not bail.
return 0
}
// Index match start+1 (long) and start+2 (short)
// Index short & long
index0 := base + 1
// Index match end-2 (long) and end-1 (short)
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
cv = load64(src, s)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
lTable[hash7(cv0>>8, lTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
lTable[hash7(cv1>>8, lTableBits)] = uint32(index1 + 1)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
sTable[hash4(cv0>>16, sTableBits)] = uint32(index0 + 2)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
emitRemainder:
@ -260,8 +300,9 @@ emitRemainder:
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterSnappyGo(dst, src []byte) (d int) {
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
@ -402,21 +443,649 @@ func encodeBlockBetterSnappyGo(dst, src []byte) (d int) {
// Do we have space for more, if not bail.
return 0
}
// Index match start+1 (long) and start+2 (short)
// Index short & long
index0 := base + 1
// Index match end-2 (long) and end-1 (short)
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
cv = load64(src, s)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
lTable[hash7(cv0>>8, lTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
lTable[hash7(cv1>>8, lTableBits)] = uint32(index1 + 1)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
sTable[hash4(cv0>>16, sTableBits)] = uint32(index0 + 2)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
emitRemainder:
if nextEmit < len(src) {
// Bail if we exceed the maximum size.
if d+len(src)-nextEmit > dstLimit {
return 0
}
d += emitLiteral(dst[d:], src[nextEmit:])
}
return d
}
// encodeBlockBetterDict encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterDict(dst, src []byte, dict *Dict) (d int) {
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
// Initialize the hash tables.
const (
// Long hash matches.
lTableBits = 17
maxLTableSize = 1 << lTableBits
// Short hash matches.
sTableBits = 14
maxSTableSize = 1 << sTableBits
maxAhead = 8 // maximum bytes ahead without checking sLimit
debug = false
)
sLimit := len(src) - inputMargin
if sLimit > MaxDictSrcOffset-maxAhead {
sLimit = MaxDictSrcOffset - maxAhead
}
if len(src) < minNonLiteralBlockSize {
return 0
}
dict.initBetter()
var lTable [maxLTableSize]uint32
var sTable [maxSTableSize]uint32
// Bail if we can't compress to at least this.
dstLimit := len(src) - len(src)>>5 - 6
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := 0
// The encoded form must start with a literal, as there are no previous
// bytes to copy, so we start looking for hash matches at s == 1.
s := 0
cv := load64(src, s)
// We initialize repeat to 0, so we never match on first attempt
repeat := len(dict.dict) - dict.repeat
// While in dict
searchDict:
for {
candidateL := 0
nextS := 0
for {
// Next src position to check
nextS = s + (s-nextEmit)>>7 + 1
if nextS > sLimit {
break searchDict
}
hashL := hash7(cv, lTableBits)
hashS := hash4(cv, sTableBits)
candidateL = int(lTable[hashL])
candidateS := int(sTable[hashS])
dictL := int(dict.betterTableLong[hashL])
dictS := int(dict.betterTableShort[hashS])
lTable[hashL] = uint32(s)
sTable[hashS] = uint32(s)
valLong := load64(src, candidateL)
valShort := load64(src, candidateS)
// If long matches at least 8 bytes, use that.
if s != 0 {
if cv == valLong {
goto emitMatch
}
if cv == valShort {
candidateL = candidateS
goto emitMatch
}
}
// Check dict repeat.
if repeat >= s+4 {
candidate := len(dict.dict) - repeat + s
if candidate > 0 && uint32(cv) == load32(dict.dict, candidate) {
// Extend back
base := s
for i := candidate; base > nextEmit && i > 0 && dict.dict[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if debug && nextEmit != base {
fmt.Println("emitted ", base-nextEmit, "literals")
}
s += 4
candidate += 4
for candidate < len(dict.dict)-8 && s <= len(src)-8 {
if diff := load64(src, s) ^ load64(dict.dict, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitRepeat(dst[d:], repeat, s-base)
if debug {
fmt.Println("emitted dict repeat length", s-base, "offset:", repeat, "s:", s)
}
nextEmit = s
if s >= sLimit {
break searchDict
}
cv = load64(src, s)
// Index in-between
index0 := base + 1
index1 := s - 2
cv = load64(src, s)
for index0 < index1 {
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 2
index1 -= 2
}
continue
}
}
// Don't try to find match at s==0
if s == 0 {
cv = load64(src, nextS)
s = nextS
continue
}
// Long likely matches 7, so take that.
if uint32(cv) == uint32(valLong) {
goto emitMatch
}
// Long dict...
if uint32(cv) == load32(dict.dict, dictL) {
candidateL = dictL
goto emitDict
}
// Check our short candidate
if uint32(cv) == uint32(valShort) {
// Try a long candidate at s+1
hashL = hash7(cv>>8, lTableBits)
candidateL = int(lTable[hashL])
lTable[hashL] = uint32(s + 1)
if uint32(cv>>8) == load32(src, candidateL) {
s++
goto emitMatch
}
// Use our short candidate.
candidateL = candidateS
goto emitMatch
}
if uint32(cv) == load32(dict.dict, dictS) {
// Try a long candidate at s+1
hashL = hash7(cv>>8, lTableBits)
candidateL = int(lTable[hashL])
lTable[hashL] = uint32(s + 1)
if uint32(cv>>8) == load32(src, candidateL) {
s++
goto emitMatch
}
candidateL = dictS
goto emitDict
}
cv = load64(src, nextS)
s = nextS
}
emitDict:
{
if debug {
if load32(dict.dict, candidateL) != load32(src, s) {
panic("dict emit mismatch")
}
}
// Extend backwards.
// The top bytes will be rechecked to get the full match.
for candidateL > 0 && s > nextEmit && dict.dict[candidateL-1] == src[s-1] {
candidateL--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
d += emitLiteral(dst[d:], src[nextEmit:s])
if debug && nextEmit != s {
fmt.Println("emitted ", s-nextEmit, "literals")
}
{
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
offset := s + (len(dict.dict)) - candidateL
// Extend the 4-byte match as long as possible.
s += 4
candidateL += 4
for s <= len(src)-8 && len(dict.dict)-candidateL >= 8 {
if diff := load64(src, s) ^ load64(dict.dict, candidateL); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidateL += 8
}
if repeat == offset {
if debug {
fmt.Println("emitted dict repeat, length", s-base, "offset:", offset, "s:", s, "dict offset:", candidateL)
}
d += emitRepeat(dst[d:], offset, s-base)
} else {
if debug {
fmt.Println("emitted dict copy, length", s-base, "offset:", offset, "s:", s, "dict offset:", candidateL)
}
// Matches longer than 64 are split.
if s <= sLimit || s-base < 8 {
d += emitCopy(dst[d:], offset, s-base)
} else {
// Split to ensure we don't start a copy within next block.
d += emitCopy(dst[d:], offset, 4)
d += emitRepeat(dst[d:], offset, s-base-4)
}
repeat = offset
}
if false {
// Validate match.
if s <= candidateL {
panic("s <= candidate")
}
a := src[base:s]
b := dict.dict[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
nextEmit = s
if s >= sLimit {
break searchDict
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Index short & long
index0 := base + 1
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
continue
}
emitMatch:
// Extend backwards
for candidateL > 0 && s > nextEmit && src[candidateL-1] == src[s-1] {
candidateL--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
base := s
offset := base - candidateL
// Extend the 4-byte match as long as possible.
s += 4
candidateL += 4
for s < len(src) {
if len(src)-s < 8 {
if src[s] == src[candidateL] {
s++
candidateL++
continue
}
break
}
if diff := load64(src, s) ^ load64(src, candidateL); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidateL += 8
}
if offset > 65535 && s-base <= 5 && repeat != offset {
// Bail if the match is equal or worse to the encoding.
s = nextS + 1
if s >= sLimit {
goto emitRemainder
}
cv = load64(src, s)
continue
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if debug && nextEmit != s {
fmt.Println("emitted ", s-nextEmit, "literals")
}
if repeat == offset {
if debug {
fmt.Println("emitted match repeat, length", s-base, "offset:", offset, "s:", s)
}
d += emitRepeat(dst[d:], offset, s-base)
} else {
if debug {
fmt.Println("emitted match copy, length", s-base, "offset:", offset, "s:", s)
}
d += emitCopy(dst[d:], offset, s-base)
repeat = offset
}
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Index short & long
index0 := base + 1
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
// Search without dict:
if repeat > s {
repeat = 0
}
// No more dict
sLimit = len(src) - inputMargin
if s >= sLimit {
goto emitRemainder
}
cv = load64(src, s)
if debug {
fmt.Println("now", s, "->", sLimit, "out:", d, "left:", len(src)-s, "nextemit:", nextEmit, "dstLimit:", dstLimit, "s:", s)
}
for {
candidateL := 0
nextS := 0
for {
// Next src position to check
nextS = s + (s-nextEmit)>>7 + 1
if nextS > sLimit {
goto emitRemainder
}
hashL := hash7(cv, lTableBits)
hashS := hash4(cv, sTableBits)
candidateL = int(lTable[hashL])
candidateS := int(sTable[hashS])
lTable[hashL] = uint32(s)
sTable[hashS] = uint32(s)
valLong := load64(src, candidateL)
valShort := load64(src, candidateS)
// If long matches at least 8 bytes, use that.
if cv == valLong {
break
}
if cv == valShort {
candidateL = candidateS
break
}
// Check repeat at offset checkRep.
const checkRep = 1
// Minimum length of a repeat. Tested with various values.
// While 4-5 offers improvements in some, 6 reduces
// regressions significantly.
const wantRepeatBytes = 6
const repeatMask = ((1 << (wantRepeatBytes * 8)) - 1) << (8 * checkRep)
if false && repeat > 0 && cv&repeatMask == load64(src, s-repeat)&repeatMask {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteral(dst[d:], src[nextEmit:base])
// Extend forward
candidate := s - repeat + wantRepeatBytes + checkRep
s += wantRepeatBytes + checkRep
for s < len(src) {
if len(src)-s < 8 {
if src[s] == src[candidate] {
s++
candidate++
continue
}
break
}
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// Index in-between
index0 := base + 1
index1 := s - 2
cv = load64(src, s)
for index0 < index1 {
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 2
index1 -= 2
}
cv = load64(src, s)
continue
}
// Long likely matches 7, so take that.
if uint32(cv) == uint32(valLong) {
break
}
// Check our short candidate
if uint32(cv) == uint32(valShort) {
// Try a long candidate at s+1
hashL = hash7(cv>>8, lTableBits)
candidateL = int(lTable[hashL])
lTable[hashL] = uint32(s + 1)
if uint32(cv>>8) == load32(src, candidateL) {
s++
break
}
// Use our short candidate.
candidateL = candidateS
break
}
cv = load64(src, nextS)
s = nextS
}
// Extend backwards
for candidateL > 0 && s > nextEmit && src[candidateL-1] == src[s-1] {
candidateL--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
base := s
offset := base - candidateL
// Extend the 4-byte match as long as possible.
s += 4
candidateL += 4
for s < len(src) {
if len(src)-s < 8 {
if src[s] == src[candidateL] {
s++
candidateL++
continue
}
break
}
if diff := load64(src, s) ^ load64(src, candidateL); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidateL += 8
}
if offset > 65535 && s-base <= 5 && repeat != offset {
// Bail if the match is equal or worse to the encoding.
s = nextS + 1
if s >= sLimit {
goto emitRemainder
}
cv = load64(src, s)
continue
}
d += emitLiteral(dst[d:], src[nextEmit:base])
if repeat == offset {
d += emitRepeat(dst[d:], offset, s-base)
} else {
d += emitCopy(dst[d:], offset, s-base)
repeat = offset
}
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Index short & long
index0 := base + 1
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
emitRemainder:

414
vendor/github.com/klauspost/compress/s2/encode_go.go generated vendored
View File

@ -4,14 +4,18 @@
package s2
import (
"bytes"
"math/bits"
)
const hasAmd64Asm = false
// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlock(dst, src []byte) (d int) {
if len(src) < minNonLiteralBlockSize {
@ -25,6 +29,7 @@ func encodeBlock(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlockBetter(dst, src []byte) (d int) {
return encodeBlockBetterGo(dst, src)
@ -35,6 +40,7 @@ func encodeBlockBetter(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlockBetterSnappy(dst, src []byte) (d int) {
return encodeBlockBetterSnappyGo(dst, src)
@ -45,6 +51,7 @@ func encodeBlockBetterSnappy(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlockSnappy(dst, src []byte) (d int) {
if len(src) < minNonLiteralBlockSize {
@ -56,6 +63,7 @@ func encodeBlockSnappy(dst, src []byte) (d int) {
// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
func emitLiteral(dst, lit []byte) int {
@ -146,6 +154,7 @@ func emitRepeat(dst []byte, offset, length int) int {
// emitCopy writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
@ -214,6 +223,7 @@ func emitCopy(dst []byte, offset, length int) int {
// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
@ -273,8 +283,8 @@ func emitCopyNoRepeat(dst []byte, offset, length int) int {
// matchLen returns how many bytes match in a and b
//
// It assumes that:
// len(a) <= len(b)
//
// len(a) <= len(b)
func matchLen(a []byte, b []byte) int {
b = b[:len(a)]
var checked int
@ -305,3 +315,405 @@ func matchLen(a []byte, b []byte) int {
}
return len(a) + checked
}
func calcBlockSize(src []byte) (d int) {
// Initialize the hash table.
const (
tableBits = 13
maxTableSize = 1 << tableBits
)
var table [maxTableSize]uint32
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := len(src) - inputMargin
// Bail if we can't compress to at least this.
dstLimit := len(src) - len(src)>>5 - 5
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := 0
// The encoded form must start with a literal, as there are no previous
// bytes to copy, so we start looking for hash matches at s == 1.
s := 1
cv := load64(src, s)
// We search for a repeat at -1, but don't output repeats when nextEmit == 0
repeat := 1
for {
candidate := 0
for {
// Next src position to check
nextS := s + (s-nextEmit)>>6 + 4
if nextS > sLimit {
goto emitRemainder
}
hash0 := hash6(cv, tableBits)
hash1 := hash6(cv>>8, tableBits)
candidate = int(table[hash0])
candidate2 := int(table[hash1])
table[hash0] = uint32(s)
table[hash1] = uint32(s + 1)
hash2 := hash6(cv>>16, tableBits)
// Check repeat at offset checkRep.
const checkRep = 1
if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteralSize(src[nextEmit:base])
// Extend forward
candidate := s - repeat + 4 + checkRep
s += 4 + checkRep
for s <= sLimit {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitCopyNoRepeatSize(repeat, s-base)
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
cv = load64(src, s)
continue
}
if uint32(cv) == load32(src, candidate) {
break
}
candidate = int(table[hash2])
if uint32(cv>>8) == load32(src, candidate2) {
table[hash2] = uint32(s + 2)
candidate = candidate2
s++
break
}
table[hash2] = uint32(s + 2)
if uint32(cv>>16) == load32(src, candidate) {
s += 2
break
}
cv = load64(src, nextS)
s = nextS
}
// Extend backwards
for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
candidate--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
d += emitLiteralSize(src[nextEmit:s])
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
repeat = base - candidate
// Extend the 4-byte match as long as possible.
s += 4
candidate += 4
for s <= len(src)-8 {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitCopyNoRepeatSize(repeat, s-base)
if false {
// Validate match.
a := src[base:s]
b := src[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Check for an immediate match, otherwise start search at s+1
x := load64(src, s-2)
m2Hash := hash6(x, tableBits)
currHash := hash6(x>>16, tableBits)
candidate = int(table[currHash])
table[m2Hash] = uint32(s - 2)
table[currHash] = uint32(s)
if uint32(x>>16) != load32(src, candidate) {
cv = load64(src, s+1)
s++
break
}
}
}
emitRemainder:
if nextEmit < len(src) {
// Bail if we exceed the maximum size.
if d+len(src)-nextEmit > dstLimit {
return 0
}
d += emitLiteralSize(src[nextEmit:])
}
return d
}
func calcBlockSizeSmall(src []byte) (d int) {
// Initialize the hash table.
const (
tableBits = 9
maxTableSize = 1 << tableBits
)
var table [maxTableSize]uint32
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := len(src) - inputMargin
// Bail if we can't compress to at least this.
dstLimit := len(src) - len(src)>>5 - 5
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := 0
// The encoded form must start with a literal, as there are no previous
// bytes to copy, so we start looking for hash matches at s == 1.
s := 1
cv := load64(src, s)
// We search for a repeat at -1, but don't output repeats when nextEmit == 0
repeat := 1
for {
candidate := 0
for {
// Next src position to check
nextS := s + (s-nextEmit)>>6 + 4
if nextS > sLimit {
goto emitRemainder
}
hash0 := hash6(cv, tableBits)
hash1 := hash6(cv>>8, tableBits)
candidate = int(table[hash0])
candidate2 := int(table[hash1])
table[hash0] = uint32(s)
table[hash1] = uint32(s + 1)
hash2 := hash6(cv>>16, tableBits)
// Check repeat at offset checkRep.
const checkRep = 1
if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
i--
base--
}
d += emitLiteralSize(src[nextEmit:base])
// Extend forward
candidate := s - repeat + 4 + checkRep
s += 4 + checkRep
for s <= sLimit {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitCopyNoRepeatSize(repeat, s-base)
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
cv = load64(src, s)
continue
}
if uint32(cv) == load32(src, candidate) {
break
}
candidate = int(table[hash2])
if uint32(cv>>8) == load32(src, candidate2) {
table[hash2] = uint32(s + 2)
candidate = candidate2
s++
break
}
table[hash2] = uint32(s + 2)
if uint32(cv>>16) == load32(src, candidate) {
s += 2
break
}
cv = load64(src, nextS)
s = nextS
}
// Extend backwards
for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
candidate--
s--
}
// Bail if we exceed the maximum size.
if d+(s-nextEmit) > dstLimit {
return 0
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
d += emitLiteralSize(src[nextEmit:s])
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
repeat = base - candidate
// Extend the 4-byte match as long as possible.
s += 4
candidate += 4
for s <= len(src)-8 {
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
s += bits.TrailingZeros64(diff) >> 3
break
}
s += 8
candidate += 8
}
d += emitCopyNoRepeatSize(repeat, s-base)
if false {
// Validate match.
a := src[base:s]
b := src[base-repeat : base-repeat+(s-base)]
if !bytes.Equal(a, b) {
panic("mismatch")
}
}
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
if d > dstLimit {
// Do we have space for more, if not bail.
return 0
}
// Check for an immediate match, otherwise start search at s+1
x := load64(src, s-2)
m2Hash := hash6(x, tableBits)
currHash := hash6(x>>16, tableBits)
candidate = int(table[currHash])
table[m2Hash] = uint32(s - 2)
table[currHash] = uint32(s)
if uint32(x>>16) != load32(src, candidate) {
cv = load64(src, s+1)
s++
break
}
}
}
emitRemainder:
if nextEmit < len(src) {
// Bail if we exceed the maximum size.
if d+len(src)-nextEmit > dstLimit {
return 0
}
d += emitLiteralSize(src[nextEmit:])
}
return d
}
// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
func emitLiteralSize(lit []byte) int {
if len(lit) == 0 {
return 0
}
switch {
case len(lit) <= 60:
return len(lit) + 1
case len(lit) <= 1<<8:
return len(lit) + 2
case len(lit) <= 1<<16:
return len(lit) + 3
case len(lit) <= 1<<24:
return len(lit) + 4
default:
return len(lit) + 5
}
}
func cvtLZ4BlockAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
panic("cvtLZ4BlockAsm should be unreachable")
}
func cvtLZ4BlockSnappyAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
panic("cvtLZ4BlockSnappyAsm should be unreachable")
}

47
vendor/github.com/klauspost/compress/s2/encodeblock_amd64.go generated vendored
View File

@ -1,7 +1,6 @@
// Code generated by command: go run gen.go -out ../encodeblock_amd64.s -stubs ../encodeblock_amd64.go -pkg=s2. DO NOT EDIT.
//go:build !appengine && !noasm && gc && !noasm
// +build !appengine,!noasm,gc,!noasm
package s2
@ -147,11 +146,26 @@ func encodeSnappyBetterBlockAsm10B(dst []byte, src []byte) int
//go:noescape
func encodeSnappyBetterBlockAsm8B(dst []byte, src []byte) int
// calcBlockSize encodes a non-empty src to a guaranteed-large-enough dst.
// Maximum input 4294967295 bytes.
// It assumes that the varint-encoded length of the decompressed bytes has already been written.
//
//go:noescape
func calcBlockSize(src []byte) int
// calcBlockSizeSmall encodes a non-empty src to a guaranteed-large-enough dst.
// Maximum input 1024 bytes.
// It assumes that the varint-encoded length of the decompressed bytes has already been written.
//
//go:noescape
func calcBlockSizeSmall(src []byte) int
// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
// dst is long enough to hold the encoded bytes with margin of 0 bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
//
// dst is long enough to hold the encoded bytes with margin of 0 bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
//
//go:noescape
func emitLiteral(dst []byte, lit []byte) int
@ -165,9 +179,10 @@ func emitRepeat(dst []byte, offset int, length int) int
// emitCopy writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
//go:noescape
func emitCopy(dst []byte, offset int, length int) int
@ -175,9 +190,10 @@ func emitCopy(dst []byte, offset int, length int) int
// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
//go:noescape
func emitCopyNoRepeat(dst []byte, offset int, length int) int
@ -185,7 +201,18 @@ func emitCopyNoRepeat(dst []byte, offset int, length int) int
// matchLen returns how many bytes match in a and b
//
// It assumes that:
// len(a) <= len(b)
//
// len(a) <= len(b)
//
//go:noescape
func matchLen(a []byte, b []byte) int
// cvtLZ4Block converts an LZ4 block to S2
//
//go:noescape
func cvtLZ4BlockAsm(dst []byte, src []byte) (uncompressed int, dstUsed int)
// cvtLZ4Block converts an LZ4 block to S2
//
//go:noescape
func cvtLZ4BlockSnappyAsm(dst []byte, src []byte) (uncompressed int, dstUsed int)

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// Copyright (c) 2022 Klaus Post. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package s2
import (
"encoding/binary"
"errors"
"fmt"
)
// LZ4Converter provides conversion from LZ4 blocks as defined here:
// https://github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md
type LZ4Converter struct {
}
// ErrDstTooSmall is returned when provided destination is too small.
var ErrDstTooSmall = errors.New("s2: destination too small")
// ConvertBlock will convert an LZ4 block and append it as an S2
// block without block length to dst.
// The uncompressed size is returned as well.
// dst must have capacity to contain the entire compressed block.
func (l *LZ4Converter) ConvertBlock(dst, src []byte) ([]byte, int, error) {
if len(src) == 0 {
return dst, 0, nil
}
const debug = false
const inline = true
const lz4MinMatch = 4
s, d := 0, len(dst)
dst = dst[:cap(dst)]
if !debug && hasAmd64Asm {
res, sz := cvtLZ4BlockAsm(dst[d:], src)
if res < 0 {
const (
errCorrupt = -1
errDstTooSmall = -2
)
switch res {
case errCorrupt:
return nil, 0, ErrCorrupt
case errDstTooSmall:
return nil, 0, ErrDstTooSmall
default:
return nil, 0, fmt.Errorf("unexpected result: %d", res)
}
}
if d+sz > len(dst) {
return nil, 0, ErrDstTooSmall
}
return dst[:d+sz], res, nil
}
dLimit := len(dst) - 10
var lastOffset uint16
var uncompressed int
if debug {
fmt.Printf("convert block start: len(src): %d, len(dst):%d \n", len(src), len(dst))
}
for {
if s >= len(src) {
return dst[:d], 0, ErrCorrupt
}
// Read literal info
token := src[s]
ll := int(token >> 4)
ml := int(lz4MinMatch + (token & 0xf))
// If upper nibble is 15, literal length is extended
if token >= 0xf0 {
for {
s++
if s >= len(src) {
if debug {
fmt.Printf("error reading ll: s (%d) >= len(src) (%d)\n", s, len(src))
}
return dst[:d], 0, ErrCorrupt
}
val := src[s]
ll += int(val)
if val != 255 {
break
}
}
}
// Skip past token
if s+ll >= len(src) {
if debug {
fmt.Printf("error literals: s+ll (%d+%d) >= len(src) (%d)\n", s, ll, len(src))
}
return nil, 0, ErrCorrupt
}
s++
if ll > 0 {
if d+ll > dLimit {
return nil, 0, ErrDstTooSmall
}
if debug {
fmt.Printf("emit %d literals\n", ll)
}
d += emitLiteralGo(dst[d:], src[s:s+ll])
s += ll
uncompressed += ll
}
// Check if we are done...
if s == len(src) && ml == lz4MinMatch {
break
}
// 2 byte offset
if s >= len(src)-2 {
if debug {
fmt.Printf("s (%d) >= len(src)-2 (%d)", s, len(src)-2)
}
return nil, 0, ErrCorrupt
}
offset := binary.LittleEndian.Uint16(src[s:])
s += 2
if offset == 0 {
if debug {
fmt.Printf("error: offset 0, ml: %d, len(src)-s: %d\n", ml, len(src)-s)
}
return nil, 0, ErrCorrupt
}
if int(offset) > uncompressed {
if debug {
fmt.Printf("error: offset (%d)> uncompressed (%d)\n", offset, uncompressed)
}
return nil, 0, ErrCorrupt
}
if ml == lz4MinMatch+15 {
for {
if s >= len(src) {
if debug {
fmt.Printf("error reading ml: s (%d) >= len(src) (%d)\n", s, len(src))
}
return nil, 0, ErrCorrupt
}
val := src[s]
s++
ml += int(val)
if val != 255 {
if s >= len(src) {
if debug {
fmt.Printf("error reading ml: s (%d) >= len(src) (%d)\n", s, len(src))
}
return nil, 0, ErrCorrupt
}
break
}
}
}
if offset == lastOffset {
if debug {
fmt.Printf("emit repeat, length: %d, offset: %d\n", ml, offset)
}
if !inline {
d += emitRepeat16(dst[d:], offset, ml)
} else {
length := ml
dst := dst[d:]
for len(dst) > 5 {
// Repeat offset, make length cheaper
length -= 4
if length <= 4 {
dst[0] = uint8(length)<<2 | tagCopy1
dst[1] = 0
d += 2
break
}
if length < 8 && offset < 2048 {
// Encode WITH offset
dst[1] = uint8(offset)
dst[0] = uint8(offset>>8)<<5 | uint8(length)<<2 | tagCopy1
d += 2
break
}
if length < (1<<8)+4 {
length -= 4
dst[2] = uint8(length)
dst[1] = 0
dst[0] = 5<<2 | tagCopy1
d += 3
break
}
if length < (1<<16)+(1<<8) {
length -= 1 << 8
dst[3] = uint8(length >> 8)
dst[2] = uint8(length >> 0)
dst[1] = 0
dst[0] = 6<<2 | tagCopy1
d += 4
break
}
const maxRepeat = (1 << 24) - 1
length -= 1 << 16
left := 0
if length > maxRepeat {
left = length - maxRepeat + 4
length = maxRepeat - 4
}
dst[4] = uint8(length >> 16)
dst[3] = uint8(length >> 8)
dst[2] = uint8(length >> 0)
dst[1] = 0
dst[0] = 7<<2 | tagCopy1
if left > 0 {
d += 5 + emitRepeat16(dst[5:], offset, left)
break
}
d += 5
break
}
}
} else {
if debug {
fmt.Printf("emit copy, length: %d, offset: %d\n", ml, offset)
}
if !inline {
d += emitCopy16(dst[d:], offset, ml)
} else {
length := ml
dst := dst[d:]
for len(dst) > 5 {
// Offset no more than 2 bytes.
if length > 64 {
off := 3
if offset < 2048 {
// emit 8 bytes as tagCopy1, rest as repeats.
dst[1] = uint8(offset)
dst[0] = uint8(offset>>8)<<5 | uint8(8-4)<<2 | tagCopy1
length -= 8
off = 2
} else {
// Emit a length 60 copy, encoded as 3 bytes.
// Emit remaining as repeat value (minimum 4 bytes).
dst[2] = uint8(offset >> 8)
dst[1] = uint8(offset)
dst[0] = 59<<2 | tagCopy2
length -= 60
}
// Emit remaining as repeats, at least 4 bytes remain.
d += off + emitRepeat16(dst[off:], offset, length)
break
}
if length >= 12 || offset >= 2048 {
// Emit the remaining copy, encoded as 3 bytes.
dst[2] = uint8(offset >> 8)
dst[1] = uint8(offset)
dst[0] = uint8(length-1)<<2 | tagCopy2
d += 3
break
}
// Emit the remaining copy, encoded as 2 bytes.
dst[1] = uint8(offset)
dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
d += 2
break
}
}
lastOffset = offset
}
uncompressed += ml
if d > dLimit {
return nil, 0, ErrDstTooSmall
}
}
return dst[:d], uncompressed, nil
}
// ConvertBlockSnappy will convert an LZ4 block and append it
// as a Snappy block without block length to dst.
// The uncompressed size is returned as well.
// dst must have capacity to contain the entire compressed block.
func (l *LZ4Converter) ConvertBlockSnappy(dst, src []byte) ([]byte, int, error) {
if len(src) == 0 {
return dst, 0, nil
}
const debug = false
const lz4MinMatch = 4
s, d := 0, len(dst)
dst = dst[:cap(dst)]
// Use assembly when possible
if !debug && hasAmd64Asm {
res, sz := cvtLZ4BlockSnappyAsm(dst[d:], src)
if res < 0 {
const (
errCorrupt = -1
errDstTooSmall = -2
)
switch res {
case errCorrupt:
return nil, 0, ErrCorrupt
case errDstTooSmall:
return nil, 0, ErrDstTooSmall
default:
return nil, 0, fmt.Errorf("unexpected result: %d", res)
}
}
if d+sz > len(dst) {
return nil, 0, ErrDstTooSmall
}
return dst[:d+sz], res, nil
}
dLimit := len(dst) - 10
var uncompressed int
if debug {
fmt.Printf("convert block start: len(src): %d, len(dst):%d \n", len(src), len(dst))
}
for {
if s >= len(src) {
return nil, 0, ErrCorrupt
}
// Read literal info
token := src[s]
ll := int(token >> 4)
ml := int(lz4MinMatch + (token & 0xf))
// If upper nibble is 15, literal length is extended
if token >= 0xf0 {
for {
s++
if s >= len(src) {
if debug {
fmt.Printf("error reading ll: s (%d) >= len(src) (%d)\n", s, len(src))
}
return nil, 0, ErrCorrupt
}
val := src[s]
ll += int(val)
if val != 255 {
break
}
}
}
// Skip past token
if s+ll >= len(src) {
if debug {
fmt.Printf("error literals: s+ll (%d+%d) >= len(src) (%d)\n", s, ll, len(src))
}
return nil, 0, ErrCorrupt
}
s++
if ll > 0 {
if d+ll > dLimit {
return nil, 0, ErrDstTooSmall
}
if debug {
fmt.Printf("emit %d literals\n", ll)
}
d += emitLiteralGo(dst[d:], src[s:s+ll])
s += ll
uncompressed += ll
}
// Check if we are done...
if s == len(src) && ml == lz4MinMatch {
break
}
// 2 byte offset
if s >= len(src)-2 {
if debug {
fmt.Printf("s (%d) >= len(src)-2 (%d)", s, len(src)-2)
}
return nil, 0, ErrCorrupt
}
offset := binary.LittleEndian.Uint16(src[s:])
s += 2
if offset == 0 {
if debug {
fmt.Printf("error: offset 0, ml: %d, len(src)-s: %d\n", ml, len(src)-s)
}
return nil, 0, ErrCorrupt
}
if int(offset) > uncompressed {
if debug {
fmt.Printf("error: offset (%d)> uncompressed (%d)\n", offset, uncompressed)
}
return nil, 0, ErrCorrupt
}
if ml == lz4MinMatch+15 {
for {
if s >= len(src) {
if debug {
fmt.Printf("error reading ml: s (%d) >= len(src) (%d)\n", s, len(src))
}
return nil, 0, ErrCorrupt
}
val := src[s]
s++
ml += int(val)
if val != 255 {
if s >= len(src) {
if debug {
fmt.Printf("error reading ml: s (%d) >= len(src) (%d)\n", s, len(src))
}
return nil, 0, ErrCorrupt
}
break
}
}
}
if debug {
fmt.Printf("emit copy, length: %d, offset: %d\n", ml, offset)
}
length := ml
// d += emitCopyNoRepeat(dst[d:], int(offset), ml)
for length > 0 {
if d >= dLimit {
return nil, 0, ErrDstTooSmall
}
// Offset no more than 2 bytes.
if length > 64 {
// Emit a length 64 copy, encoded as 3 bytes.
dst[d+2] = uint8(offset >> 8)
dst[d+1] = uint8(offset)
dst[d+0] = 63<<2 | tagCopy2
length -= 64
d += 3
continue
}
if length >= 12 || offset >= 2048 || length < 4 {
// Emit the remaining copy, encoded as 3 bytes.
dst[d+2] = uint8(offset >> 8)
dst[d+1] = uint8(offset)
dst[d+0] = uint8(length-1)<<2 | tagCopy2
d += 3
break
}
// Emit the remaining copy, encoded as 2 bytes.
dst[d+1] = uint8(offset)
dst[d+0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
d += 2
break
}
uncompressed += ml
if d > dLimit {
return nil, 0, ErrDstTooSmall
}
}
return dst[:d], uncompressed, nil
}
// emitRepeat writes a repeat chunk and returns the number of bytes written.
// Length must be at least 4 and < 1<<24
func emitRepeat16(dst []byte, offset uint16, length int) int {
// Repeat offset, make length cheaper
length -= 4
if length <= 4 {
dst[0] = uint8(length)<<2 | tagCopy1
dst[1] = 0
return 2
}
if length < 8 && offset < 2048 {
// Encode WITH offset
dst[1] = uint8(offset)
dst[0] = uint8(offset>>8)<<5 | uint8(length)<<2 | tagCopy1
return 2
}
if length < (1<<8)+4 {
length -= 4
dst[2] = uint8(length)
dst[1] = 0
dst[0] = 5<<2 | tagCopy1
return 3
}
if length < (1<<16)+(1<<8) {
length -= 1 << 8
dst[3] = uint8(length >> 8)
dst[2] = uint8(length >> 0)
dst[1] = 0
dst[0] = 6<<2 | tagCopy1
return 4
}
const maxRepeat = (1 << 24) - 1
length -= 1 << 16
left := 0
if length > maxRepeat {
left = length - maxRepeat + 4
length = maxRepeat - 4
}
dst[4] = uint8(length >> 16)
dst[3] = uint8(length >> 8)
dst[2] = uint8(length >> 0)
dst[1] = 0
dst[0] = 7<<2 | tagCopy1
if left > 0 {
return 5 + emitRepeat16(dst[5:], offset, left)
}
return 5
}
// emitCopy writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint16
// 4 <= length && length <= math.MaxUint32
func emitCopy16(dst []byte, offset uint16, length int) int {
// Offset no more than 2 bytes.
if length > 64 {
off := 3
if offset < 2048 {
// emit 8 bytes as tagCopy1, rest as repeats.
dst[1] = uint8(offset)
dst[0] = uint8(offset>>8)<<5 | uint8(8-4)<<2 | tagCopy1
length -= 8
off = 2
} else {
// Emit a length 60 copy, encoded as 3 bytes.
// Emit remaining as repeat value (minimum 4 bytes).
dst[2] = uint8(offset >> 8)
dst[1] = uint8(offset)
dst[0] = 59<<2 | tagCopy2
length -= 60
}
// Emit remaining as repeats, at least 4 bytes remain.
return off + emitRepeat16(dst[off:], offset, length)
}
if length >= 12 || offset >= 2048 {
// Emit the remaining copy, encoded as 3 bytes.
dst[2] = uint8(offset >> 8)
dst[1] = uint8(offset)
dst[0] = uint8(length-1)<<2 | tagCopy2
return 3
}
// Emit the remaining copy, encoded as 2 bytes.
dst[1] = uint8(offset)
dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
return 2
}
// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
func emitLiteralGo(dst, lit []byte) int {
if len(lit) == 0 {
return 0
}
i, n := 0, uint(len(lit)-1)
switch {
case n < 60:
dst[0] = uint8(n)<<2 | tagLiteral
i = 1
case n < 1<<8:
dst[1] = uint8(n)
dst[0] = 60<<2 | tagLiteral
i = 2
case n < 1<<16:
dst[2] = uint8(n >> 8)
dst[1] = uint8(n)
dst[0] = 61<<2 | tagLiteral
i = 3
case n < 1<<24:
dst[3] = uint8(n >> 16)
dst[2] = uint8(n >> 8)
dst[1] = uint8(n)
dst[0] = 62<<2 | tagLiteral
i = 4
default:
dst[4] = uint8(n >> 24)
dst[3] = uint8(n >> 16)
dst[2] = uint8(n >> 8)
dst[1] = uint8(n)
dst[0] = 63<<2 | tagLiteral
i = 5
}
return i + copy(dst[i:], lit)
}