495 lines
12 KiB
Go
495 lines
12 KiB
Go
package internal
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import (
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"bufio"
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"bytes"
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"errors"
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"fmt"
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"io"
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"github.com/klauspost/compress/gzip"
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"github.com/klauspost/compress/zlib"
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"github.com/klauspost/compress/zstd"
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"github.com/klauspost/pgzip"
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)
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const defaultMaxDecompressionSize int64 = 500 * 1024 * 1024 // 500MB
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// DecodingOption provide methods to change the decoding from the standard
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// configuration.
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type DecodingOption func(*decoderConfig)
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type decoderConfig struct {
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maxDecompressionSize int64
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}
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func WithMaxDecompressionSize(maxDecompressionSize int64) DecodingOption {
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return func(cfg *decoderConfig) {
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cfg.maxDecompressionSize = maxDecompressionSize
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}
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}
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type encoderConfig struct {
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level int
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}
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// EncodingOption provide methods to change the encoding from the standard
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// configuration.
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type EncodingOption func(*encoderConfig)
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func WithCompressionLevel(level int) EncodingOption {
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return func(cfg *encoderConfig) {
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cfg.level = level
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}
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}
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// NewStreamContentDecoder returns a reader that will decode the stream
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// according to the encoding type.
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func NewStreamContentDecoder(encoding string, r io.Reader) (io.Reader, error) {
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switch encoding {
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case "gzip":
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return NewGzipReader(r)
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case "identity", "":
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return r, nil
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default:
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return nil, errors.New("invalid value for content_encoding")
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}
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}
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// GzipReader is similar to gzip.Reader but reads only a single gzip stream per read.
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type GzipReader struct {
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r io.Reader
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z *pgzip.Reader
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endOfStream bool
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}
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func NewGzipReader(r io.Reader) (io.Reader, error) {
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// We need a read that implements ByteReader in order to line up the next
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// stream.
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br := bufio.NewReader(r)
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// Reads the first gzip stream header.
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z, err := pgzip.NewReader(br)
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if err != nil {
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return nil, err
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}
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// Prevent future calls to Read from reading the following gzip header.
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z.Multistream(false)
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return &GzipReader{r: br, z: z}, nil
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}
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func (r *GzipReader) Read(b []byte) (int, error) {
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if r.endOfStream {
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// Reads the next gzip header and prepares for the next stream.
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err := r.z.Reset(r.r)
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if err != nil {
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return 0, err
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}
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r.z.Multistream(false)
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r.endOfStream = false
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}
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n, err := r.z.Read(b)
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// Since multistream is disabled, io.EOF indicates the end of the gzip
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// sequence. On the next read we must read the next gzip header.
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if errors.Is(err, io.EOF) {
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r.endOfStream = true
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return n, nil
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}
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return n, err
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}
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// NewContentEncoder returns a ContentEncoder for the encoding type.
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func NewContentEncoder(encoding string, options ...EncodingOption) (ContentEncoder, error) {
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switch encoding {
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case "gzip":
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return NewGzipEncoder(options...)
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case "identity", "":
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return NewIdentityEncoder(options...)
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case "zlib":
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return NewZlibEncoder(options...)
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case "zstd":
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return NewZstdEncoder(options...)
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default:
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return nil, errors.New("invalid value for content_encoding")
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}
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}
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type AutoDecoder struct {
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encoding string
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gzip *GzipDecoder
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identity *IdentityDecoder
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}
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func (a *AutoDecoder) SetEncoding(encoding string) {
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a.encoding = encoding
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}
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func (a *AutoDecoder) Decode(data []byte) ([]byte, error) {
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if a.encoding == "gzip" {
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return a.gzip.Decode(data)
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}
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return a.identity.Decode(data)
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}
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func NewAutoContentDecoder(options ...DecodingOption) *AutoDecoder {
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var a AutoDecoder
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a.identity = NewIdentityDecoder(options...)
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a.gzip = NewGzipDecoder(options...)
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return &a
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}
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// NewContentDecoder returns a ContentDecoder for the encoding type.
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func NewContentDecoder(encoding string, options ...DecodingOption) (ContentDecoder, error) {
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switch encoding {
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case "auto":
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return NewAutoContentDecoder(options...), nil
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case "gzip":
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return NewGzipDecoder(options...), nil
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case "identity", "":
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return NewIdentityDecoder(options...), nil
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case "zlib":
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return NewZlibDecoder(options...), nil
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case "zstd":
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return NewZstdDecoder(options...)
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default:
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return nil, errors.New("invalid value for content_encoding")
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}
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}
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// ContentEncoder applies a wrapper encoding to byte buffers.
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type ContentEncoder interface {
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Encode([]byte) ([]byte, error)
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}
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// GzipEncoder compresses the buffer using gzip at the default level.
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type GzipEncoder struct {
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pwriter *pgzip.Writer
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writer *gzip.Writer
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buf *bytes.Buffer
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}
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func NewGzipEncoder(options ...EncodingOption) (*GzipEncoder, error) {
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cfg := encoderConfig{level: gzip.DefaultCompression}
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for _, o := range options {
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o(&cfg)
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}
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// Check if the compression level is supported
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switch cfg.level {
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case gzip.NoCompression, gzip.DefaultCompression, gzip.BestSpeed, gzip.BestCompression:
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// Do nothing as those are valid levels
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default:
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return nil, errors.New("invalid compression level, only 0, 1 and 9 are supported")
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}
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var buf bytes.Buffer
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pw, err := pgzip.NewWriterLevel(&buf, cfg.level)
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if err != nil {
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return nil, err
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}
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w, err := gzip.NewWriterLevel(&buf, cfg.level)
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return &GzipEncoder{
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pwriter: pw,
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writer: w,
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buf: &buf,
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}, err
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}
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func (e *GzipEncoder) Encode(data []byte) ([]byte, error) {
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// Parallel Gzip is only faster for larger data chunks. According to the
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// project's documentation the trade-off size is at about 1MB, so we switch
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// to parallel Gzip if the data is larger and run the built-in version
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// otherwise.
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if len(data) > 1024*1024 {
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return e.encodeBig(data)
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}
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return e.encodeSmall(data)
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}
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func (e *GzipEncoder) encodeSmall(data []byte) ([]byte, error) {
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e.buf.Reset()
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e.writer.Reset(e.buf)
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_, err := e.writer.Write(data)
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if err != nil {
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return nil, err
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}
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err = e.writer.Close()
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if err != nil {
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return nil, err
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}
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return e.buf.Bytes(), nil
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}
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func (e *GzipEncoder) encodeBig(data []byte) ([]byte, error) {
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e.buf.Reset()
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e.pwriter.Reset(e.buf)
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_, err := e.pwriter.Write(data)
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if err != nil {
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return nil, err
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}
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err = e.pwriter.Close()
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if err != nil {
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return nil, err
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}
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return e.buf.Bytes(), nil
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}
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type ZlibEncoder struct {
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writer *zlib.Writer
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buf *bytes.Buffer
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}
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func NewZlibEncoder(options ...EncodingOption) (*ZlibEncoder, error) {
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cfg := encoderConfig{level: zlib.DefaultCompression}
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for _, o := range options {
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o(&cfg)
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}
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switch cfg.level {
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case zlib.NoCompression, zlib.DefaultCompression, zlib.BestSpeed, zlib.BestCompression:
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// Do nothing as those are valid levels
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default:
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return nil, errors.New("invalid compression level, only 0, 1 and 9 are supported")
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}
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var buf bytes.Buffer
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w, err := zlib.NewWriterLevel(&buf, cfg.level)
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return &ZlibEncoder{
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writer: w,
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buf: &buf,
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}, err
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}
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func (e *ZlibEncoder) Encode(data []byte) ([]byte, error) {
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e.buf.Reset()
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e.writer.Reset(e.buf)
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_, err := e.writer.Write(data)
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if err != nil {
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return nil, err
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}
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err = e.writer.Close()
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if err != nil {
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return nil, err
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}
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return e.buf.Bytes(), nil
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}
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type ZstdEncoder struct {
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encoder *zstd.Encoder
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}
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func NewZstdEncoder(options ...EncodingOption) (*ZstdEncoder, error) {
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cfg := encoderConfig{level: 3}
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for _, o := range options {
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o(&cfg)
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}
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// Map the levels
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var level zstd.EncoderLevel
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switch cfg.level {
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case 1:
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level = zstd.SpeedFastest
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case 3:
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level = zstd.SpeedDefault
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case 7:
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level = zstd.SpeedBetterCompression
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case 11:
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level = zstd.SpeedBestCompression
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default:
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return nil, errors.New("invalid compression level, only 1, 3, 7 and 11 are supported")
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}
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e, err := zstd.NewWriter(nil, zstd.WithEncoderLevel(level))
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return &ZstdEncoder{
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encoder: e,
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}, err
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}
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func (e *ZstdEncoder) Encode(data []byte) ([]byte, error) {
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return e.encoder.EncodeAll(data, make([]byte, 0, len(data))), nil
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}
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// IdentityEncoder is a null encoder that applies no transformation.
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type IdentityEncoder struct{}
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func NewIdentityEncoder(options ...EncodingOption) (*IdentityEncoder, error) {
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if len(options) > 0 {
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return nil, errors.New("identity encoder does not support options")
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}
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return &IdentityEncoder{}, nil
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}
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func (*IdentityEncoder) Encode(data []byte) ([]byte, error) {
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return data, nil
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}
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// ContentDecoder removes a wrapper encoding from byte buffers.
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type ContentDecoder interface {
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SetEncoding(string)
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Decode([]byte) ([]byte, error)
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}
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// GzipDecoder decompresses buffers with gzip compression.
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type GzipDecoder struct {
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preader *pgzip.Reader
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reader *gzip.Reader
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buf *bytes.Buffer
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maxDecompressionSize int64
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}
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func NewGzipDecoder(options ...DecodingOption) *GzipDecoder {
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cfg := decoderConfig{maxDecompressionSize: defaultMaxDecompressionSize}
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for _, o := range options {
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o(&cfg)
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}
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return &GzipDecoder{
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preader: new(pgzip.Reader),
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reader: new(gzip.Reader),
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buf: new(bytes.Buffer),
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maxDecompressionSize: cfg.maxDecompressionSize,
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}
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}
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func (*GzipDecoder) SetEncoding(string) {}
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func (d *GzipDecoder) Decode(data []byte) ([]byte, error) {
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// Parallel Gzip is only faster for larger data chunks. According to the
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// project's documentation the trade-off size is at about 1MB, so we switch
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// to parallel Gzip if the data is larger and run the built-in version
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// otherwise.
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if len(data) > 1024*1024 {
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return d.decodeBig(data)
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}
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return d.decodeSmall(data)
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}
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func (d *GzipDecoder) decodeSmall(data []byte) ([]byte, error) {
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err := d.reader.Reset(bytes.NewBuffer(data))
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if err != nil {
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return nil, err
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}
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d.buf.Reset()
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n, err := io.CopyN(d.buf, d.reader, d.maxDecompressionSize)
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if err != nil && !errors.Is(err, io.EOF) {
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return nil, err
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} else if n == d.maxDecompressionSize {
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return nil, fmt.Errorf("size of decoded data exceeds allowed size %d", d.maxDecompressionSize)
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}
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err = d.reader.Close()
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if err != nil {
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return nil, err
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}
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return d.buf.Bytes(), nil
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}
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func (d *GzipDecoder) decodeBig(data []byte) ([]byte, error) {
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err := d.preader.Reset(bytes.NewBuffer(data))
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if err != nil {
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return nil, err
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}
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d.buf.Reset()
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n, err := io.CopyN(d.buf, d.preader, d.maxDecompressionSize)
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if err != nil && !errors.Is(err, io.EOF) {
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return nil, err
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} else if n == d.maxDecompressionSize {
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return nil, fmt.Errorf("size of decoded data exceeds allowed size %d", d.maxDecompressionSize)
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}
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err = d.preader.Close()
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if err != nil {
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return nil, err
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}
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return d.buf.Bytes(), nil
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}
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type ZlibDecoder struct {
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buf *bytes.Buffer
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maxDecompressionSize int64
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}
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func NewZlibDecoder(options ...DecodingOption) *ZlibDecoder {
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cfg := decoderConfig{maxDecompressionSize: defaultMaxDecompressionSize}
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for _, o := range options {
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o(&cfg)
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}
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return &ZlibDecoder{
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buf: new(bytes.Buffer),
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maxDecompressionSize: cfg.maxDecompressionSize,
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}
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}
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func (*ZlibDecoder) SetEncoding(string) {}
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func (d *ZlibDecoder) Decode(data []byte) ([]byte, error) {
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d.buf.Reset()
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b := bytes.NewBuffer(data)
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r, err := zlib.NewReader(b)
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if err != nil {
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return nil, err
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}
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n, err := io.CopyN(d.buf, r, d.maxDecompressionSize)
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if err != nil && !errors.Is(err, io.EOF) {
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return nil, err
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} else if n == d.maxDecompressionSize {
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return nil, fmt.Errorf("size of decoded data exceeds allowed size %d", d.maxDecompressionSize)
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}
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err = r.Close()
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if err != nil {
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return nil, err
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}
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return d.buf.Bytes(), nil
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}
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type ZstdDecoder struct {
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decoder *zstd.Decoder
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}
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func NewZstdDecoder(options ...DecodingOption) (*ZstdDecoder, error) {
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cfg := decoderConfig{maxDecompressionSize: defaultMaxDecompressionSize}
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for _, o := range options {
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o(&cfg)
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}
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d, err := zstd.NewReader(nil, zstd.WithDecoderConcurrency(0), zstd.WithDecoderMaxWindow(uint64(cfg.maxDecompressionSize)))
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return &ZstdDecoder{
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decoder: d,
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}, err
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}
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func (*ZstdDecoder) SetEncoding(string) {}
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func (d *ZstdDecoder) Decode(data []byte) ([]byte, error) {
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return d.decoder.DecodeAll(data, nil)
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}
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// IdentityDecoder is a null decoder that returns the input.
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type IdentityDecoder struct {
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}
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func NewIdentityDecoder(_ ...DecodingOption) *IdentityDecoder {
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return &IdentityDecoder{}
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}
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func (*IdentityDecoder) SetEncoding(string) {}
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func (*IdentityDecoder) Decode(data []byte) ([]byte, error) {
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return data, nil
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}
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