12a1f914f4
* 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>
122 lines
2.8 KiB
Go
Vendored
122 lines
2.8 KiB
Go
Vendored
package zstd
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"github.com/klauspost/compress/huff0"
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)
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type dict struct {
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id uint32
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litEnc *huff0.Scratch
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llDec, ofDec, mlDec sequenceDec
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//llEnc, ofEnc, mlEnc []*fseEncoder
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offsets [3]int
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content []byte
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}
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var dictMagic = [4]byte{0x37, 0xa4, 0x30, 0xec}
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// ID returns the dictionary id or 0 if d is nil.
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func (d *dict) ID() uint32 {
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if d == nil {
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return 0
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}
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return d.id
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}
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// DictContentSize returns the dictionary content size or 0 if d is nil.
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func (d *dict) DictContentSize() int {
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if d == nil {
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return 0
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}
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return len(d.content)
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}
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// Load a dictionary as described in
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// https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#dictionary-format
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func loadDict(b []byte) (*dict, error) {
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// Check static field size.
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if len(b) <= 8+(3*4) {
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return nil, io.ErrUnexpectedEOF
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}
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d := dict{
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llDec: sequenceDec{fse: &fseDecoder{}},
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ofDec: sequenceDec{fse: &fseDecoder{}},
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mlDec: sequenceDec{fse: &fseDecoder{}},
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}
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if !bytes.Equal(b[:4], dictMagic[:]) {
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return nil, ErrMagicMismatch
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}
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d.id = binary.LittleEndian.Uint32(b[4:8])
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if d.id == 0 {
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return nil, errors.New("dictionaries cannot have ID 0")
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}
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// Read literal table
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var err error
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d.litEnc, b, err = huff0.ReadTable(b[8:], nil)
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if err != nil {
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return nil, err
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}
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d.litEnc.Reuse = huff0.ReusePolicyMust
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br := byteReader{
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b: b,
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off: 0,
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}
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readDec := func(i tableIndex, dec *fseDecoder) error {
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if err := dec.readNCount(&br, uint16(maxTableSymbol[i])); err != nil {
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return err
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}
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if br.overread() {
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return io.ErrUnexpectedEOF
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}
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err = dec.transform(symbolTableX[i])
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if err != nil {
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println("Transform table error:", err)
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return err
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}
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if debug {
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println("Read table ok", "symbolLen:", dec.symbolLen)
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}
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// Set decoders as predefined so they aren't reused.
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dec.preDefined = true
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return nil
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}
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if err := readDec(tableOffsets, d.ofDec.fse); err != nil {
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return nil, err
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}
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if err := readDec(tableMatchLengths, d.mlDec.fse); err != nil {
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return nil, err
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}
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if err := readDec(tableLiteralLengths, d.llDec.fse); err != nil {
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return nil, err
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}
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if br.remain() < 12 {
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return nil, io.ErrUnexpectedEOF
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}
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d.offsets[0] = int(br.Uint32())
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br.advance(4)
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d.offsets[1] = int(br.Uint32())
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br.advance(4)
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d.offsets[2] = int(br.Uint32())
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br.advance(4)
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if d.offsets[0] <= 0 || d.offsets[1] <= 0 || d.offsets[2] <= 0 {
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return nil, errors.New("invalid offset in dictionary")
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}
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d.content = make([]byte, br.remain())
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copy(d.content, br.unread())
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if d.offsets[0] > len(d.content) || d.offsets[1] > len(d.content) || d.offsets[2] > len(d.content) {
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return nil, fmt.Errorf("initial offset bigger than dictionary content size %d, offsets: %v", len(d.content), d.offsets)
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}
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return &d, nil
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}
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