gitea/vendor/github.com/klauspost/compress/zstd/seqenc.go
6543 792b4dba2c
[Vendor] Update directly used dependencys (#15593)
* update github.com/blevesearch/bleve v2.0.2 -> v2.0.3

* github.com/denisenkom/go-mssqldb v0.9.0 -> v0.10.0

* github.com/editorconfig/editorconfig-core-go v2.4.1 -> v2.4.2

* github.com/go-chi/cors v1.1.1 -> v1.2.0

* github.com/go-git/go-billy v5.0.0 -> v5.1.0

* github.com/go-git/go-git v5.2.0 -> v5.3.0

* github.com/go-ldap/ldap v3.2.4 -> v3.3.0

* github.com/go-redis/redis v8.6.0 -> v8.8.2

* github.com/go-sql-driver/mysql v1.5.0 -> v1.6.0

* github.com/go-swagger/go-swagger v0.26.1 -> v0.27.0

* github.com/lib/pq v1.9.0 -> v1.10.1

* github.com/mattn/go-sqlite3 v1.14.6 -> v1.14.7

* github.com/go-testfixtures/testfixtures v3.5.0 -> v3.6.0

* github.com/issue9/identicon v1.0.1 -> v1.2.0

* github.com/klauspost/compress v1.11.8 -> v1.12.1

* github.com/mgechev/revive v1.0.3 -> v1.0.6

* github.com/microcosm-cc/bluemonday v1.0.7 -> v1.0.8

* github.com/niklasfasching/go-org v1.4.0 -> v1.5.0

* github.com/olivere/elastic v7.0.22 -> v7.0.24

* github.com/pelletier/go-toml v1.8.1 -> v1.9.0

* github.com/prometheus/client_golang v1.9.0 -> v1.10.0

* github.com/xanzy/go-gitlab v0.44.0 -> v0.48.0

* github.com/yuin/goldmark v1.3.3 -> v1.3.5

* github.com/6543/go-version v1.2.4 -> v1.3.1

* do github.com/lib/pq v1.10.0 -> v1.10.1 again ...
2021-04-22 20:08:53 -04:00

115 lines
3.2 KiB
Go
Vendored

// Copyright 2019+ Klaus Post. All rights reserved.
// License information can be found in the LICENSE file.
// Based on work by Yann Collet, released under BSD License.
package zstd
import "math/bits"
type seqCoders struct {
llEnc, ofEnc, mlEnc *fseEncoder
llPrev, ofPrev, mlPrev *fseEncoder
}
// swap coders with another (block).
func (s *seqCoders) swap(other *seqCoders) {
*s, *other = *other, *s
}
// setPrev will update the previous encoders to the actually used ones
// and make sure a fresh one is in the main slot.
func (s *seqCoders) setPrev(ll, ml, of *fseEncoder) {
compareSwap := func(used *fseEncoder, current, prev **fseEncoder) {
// We used the new one, more current to history and reuse the previous history
if *current == used {
*prev, *current = *current, *prev
c := *current
p := *prev
c.reUsed = false
p.reUsed = true
return
}
if used == *prev {
return
}
// Ensure we cannot reuse by accident
prevEnc := *prev
prevEnc.symbolLen = 0
}
compareSwap(ll, &s.llEnc, &s.llPrev)
compareSwap(ml, &s.mlEnc, &s.mlPrev)
compareSwap(of, &s.ofEnc, &s.ofPrev)
}
func highBit(val uint32) (n uint32) {
return uint32(bits.Len32(val) - 1)
}
var llCodeTable = [64]byte{0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
16, 16, 17, 17, 18, 18, 19, 19,
20, 20, 20, 20, 21, 21, 21, 21,
22, 22, 22, 22, 22, 22, 22, 22,
23, 23, 23, 23, 23, 23, 23, 23,
24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24}
// Up to 6 bits
const maxLLCode = 35
// llBitsTable translates from ll code to number of bits.
var llBitsTable = [maxLLCode + 1]byte{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 2, 2, 3, 3,
4, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16}
// llCode returns the code that represents the literal length requested.
func llCode(litLength uint32) uint8 {
const llDeltaCode = 19
if litLength <= 63 {
// Compiler insists on bounds check (Go 1.12)
return llCodeTable[litLength&63]
}
return uint8(highBit(litLength)) + llDeltaCode
}
var mlCodeTable = [128]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37,
38, 38, 38, 38, 38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39,
40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,
41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42}
// Up to 6 bits
const maxMLCode = 52
// mlBitsTable translates from ml code to number of bits.
var mlBitsTable = [maxMLCode + 1]byte{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 2, 2, 3, 3,
4, 4, 5, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16}
// note : mlBase = matchLength - MINMATCH;
// because it's the format it's stored in seqStore->sequences
func mlCode(mlBase uint32) uint8 {
const mlDeltaCode = 36
if mlBase <= 127 {
// Compiler insists on bounds check (Go 1.12)
return mlCodeTable[mlBase&127]
}
return uint8(highBit(mlBase)) + mlDeltaCode
}
func ofCode(offset uint32) uint8 {
// A valid offset will always be > 0.
return uint8(bits.Len32(offset) - 1)
}