forgejo/vendor/github.com/klauspost/compress/zstd/history.go
6543 12a1f914f4
Vendor Update Go Libs (#13166)
* update github.com/alecthomas/chroma v0.8.0 -> v0.8.1

* github.com/blevesearch/bleve v1.0.10 -> v1.0.12

* editorconfig-core-go v2.1.1 -> v2.3.7

* github.com/gliderlabs/ssh v0.2.2 -> v0.3.1

* migrate editorconfig.ParseBytes to Parse

* github.com/shurcooL/vfsgen to 0d455de96546

* github.com/go-git/go-git/v5 v5.1.0 -> v5.2.0

* github.com/google/uuid v1.1.1 -> v1.1.2

* github.com/huandu/xstrings v1.3.0 -> v1.3.2

* github.com/klauspost/compress v1.10.11 -> v1.11.1

* github.com/markbates/goth v1.61.2 -> v1.65.0

* github.com/mattn/go-sqlite3 v1.14.0 -> v1.14.4

* github.com/mholt/archiver v3.3.0 -> v3.3.2

* github.com/microcosm-cc/bluemonday 4f7140c49acb -> v1.0.4

* github.com/minio/minio-go v7.0.4 -> v7.0.5

* github.com/olivere/elastic v7.0.9 -> v7.0.20

* github.com/urfave/cli v1.20.0 -> v1.22.4

* github.com/prometheus/client_golang v1.1.0 -> v1.8.0

* github.com/xanzy/go-gitlab v0.37.0 -> v0.38.1

* mvdan.cc/xurls v2.1.0 -> v2.2.0

Co-authored-by: Lauris BH <lauris@nix.lv>
2020-10-16 01:06:27 -04:00

89 lines
2.3 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 (
"github.com/klauspost/compress/huff0"
)
// history contains the information transferred between blocks.
type history struct {
b []byte
huffTree *huff0.Scratch
recentOffsets [3]int
decoders sequenceDecs
windowSize int
maxSize int
error bool
dict *dict
}
// reset will reset the history to initial state of a frame.
// The history must already have been initialized to the desired size.
func (h *history) reset() {
h.b = h.b[:0]
h.error = false
h.recentOffsets = [3]int{1, 4, 8}
if f := h.decoders.litLengths.fse; f != nil && !f.preDefined {
fseDecoderPool.Put(f)
}
if f := h.decoders.offsets.fse; f != nil && !f.preDefined {
fseDecoderPool.Put(f)
}
if f := h.decoders.matchLengths.fse; f != nil && !f.preDefined {
fseDecoderPool.Put(f)
}
h.decoders = sequenceDecs{}
if h.huffTree != nil {
if h.dict == nil || h.dict.litEnc != h.huffTree {
huffDecoderPool.Put(h.huffTree)
}
}
h.huffTree = nil
h.dict = nil
//printf("history created: %+v (l: %d, c: %d)", *h, len(h.b), cap(h.b))
}
func (h *history) setDict(dict *dict) {
if dict == nil {
return
}
h.dict = dict
h.decoders.litLengths = dict.llDec
h.decoders.offsets = dict.ofDec
h.decoders.matchLengths = dict.mlDec
h.recentOffsets = dict.offsets
h.huffTree = dict.litEnc
}
// append bytes to history.
// This function will make sure there is space for it,
// if the buffer has been allocated with enough extra space.
func (h *history) append(b []byte) {
if len(b) >= h.windowSize {
// Discard all history by simply overwriting
h.b = h.b[:h.windowSize]
copy(h.b, b[len(b)-h.windowSize:])
return
}
// If there is space, append it.
if len(b) < cap(h.b)-len(h.b) {
h.b = append(h.b, b...)
return
}
// Move data down so we only have window size left.
// We know we have less than window size in b at this point.
discard := len(b) + len(h.b) - h.windowSize
copy(h.b, h.b[discard:])
h.b = h.b[:h.windowSize]
copy(h.b[h.windowSize-len(b):], b)
}
// append bytes to history without ever discarding anything.
func (h *history) appendKeep(b []byte) {
h.b = append(h.b, b...)
}