2022-03-03 08:19:41 -05:00
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// Copyright 2019+ Klaus Post. All rights reserved.
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// License information can be found in the LICENSE file.
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// Based on work by Yann Collet, released under BSD License.
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package zstd
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import (
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"crypto/rand"
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"fmt"
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"io"
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2023-03-28 10:43:43 -04:00
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"math"
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2022-03-03 08:19:41 -05:00
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rdebug "runtime/debug"
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"sync"
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"github.com/klauspost/compress/zstd/internal/xxhash"
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)
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// Encoder provides encoding to Zstandard.
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// An Encoder can be used for either compressing a stream via the
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// io.WriteCloser interface supported by the Encoder or as multiple independent
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// tasks via the EncodeAll function.
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// Smaller encodes are encouraged to use the EncodeAll function.
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// Use NewWriter to create a new instance.
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type Encoder struct {
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o encoderOptions
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encoders chan encoder
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state encoderState
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init sync.Once
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}
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type encoder interface {
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Encode(blk *blockEnc, src []byte)
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EncodeNoHist(blk *blockEnc, src []byte)
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Block() *blockEnc
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CRC() *xxhash.Digest
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AppendCRC([]byte) []byte
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WindowSize(size int64) int32
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UseBlock(*blockEnc)
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Reset(d *dict, singleBlock bool)
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}
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type encoderState struct {
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w io.Writer
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filling []byte
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current []byte
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previous []byte
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encoder encoder
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writing *blockEnc
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err error
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writeErr error
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nWritten int64
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nInput int64
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frameContentSize int64
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headerWritten bool
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eofWritten bool
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fullFrameWritten bool
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// This waitgroup indicates an encode is running.
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wg sync.WaitGroup
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// This waitgroup indicates we have a block encoding/writing.
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wWg sync.WaitGroup
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}
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// NewWriter will create a new Zstandard encoder.
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// If the encoder will be used for encoding blocks a nil writer can be used.
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func NewWriter(w io.Writer, opts ...EOption) (*Encoder, error) {
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initPredefined()
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var e Encoder
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e.o.setDefault()
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for _, o := range opts {
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err := o(&e.o)
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if err != nil {
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return nil, err
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}
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}
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if w != nil {
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e.Reset(w)
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}
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return &e, nil
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}
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func (e *Encoder) initialize() {
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if e.o.concurrent == 0 {
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e.o.setDefault()
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}
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e.encoders = make(chan encoder, e.o.concurrent)
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for i := 0; i < e.o.concurrent; i++ {
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enc := e.o.encoder()
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e.encoders <- enc
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}
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}
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// Reset will re-initialize the writer and new writes will encode to the supplied writer
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// as a new, independent stream.
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func (e *Encoder) Reset(w io.Writer) {
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s := &e.state
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s.wg.Wait()
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s.wWg.Wait()
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if cap(s.filling) == 0 {
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s.filling = make([]byte, 0, e.o.blockSize)
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}
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2022-03-16 10:16:28 -04:00
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if e.o.concurrent > 1 {
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if cap(s.current) == 0 {
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s.current = make([]byte, 0, e.o.blockSize)
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}
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if cap(s.previous) == 0 {
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s.previous = make([]byte, 0, e.o.blockSize)
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}
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s.current = s.current[:0]
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s.previous = s.previous[:0]
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if s.writing == nil {
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s.writing = &blockEnc{lowMem: e.o.lowMem}
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s.writing.init()
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}
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s.writing.initNewEncode()
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2022-03-03 08:19:41 -05:00
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}
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if s.encoder == nil {
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s.encoder = e.o.encoder()
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}
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s.filling = s.filling[:0]
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s.encoder.Reset(e.o.dict, false)
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s.headerWritten = false
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s.eofWritten = false
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s.fullFrameWritten = false
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s.w = w
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s.err = nil
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s.nWritten = 0
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s.nInput = 0
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s.writeErr = nil
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s.frameContentSize = 0
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}
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// ResetContentSize will reset and set a content size for the next stream.
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// If the bytes written does not match the size given an error will be returned
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// when calling Close().
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// This is removed when Reset is called.
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// Sizes <= 0 results in no content size set.
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func (e *Encoder) ResetContentSize(w io.Writer, size int64) {
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e.Reset(w)
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if size >= 0 {
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e.state.frameContentSize = size
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}
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}
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// Write data to the encoder.
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// Input data will be buffered and as the buffer fills up
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// content will be compressed and written to the output.
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// When done writing, use Close to flush the remaining output
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// and write CRC if requested.
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func (e *Encoder) Write(p []byte) (n int, err error) {
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s := &e.state
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for len(p) > 0 {
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if len(p)+len(s.filling) < e.o.blockSize {
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if e.o.crc {
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_, _ = s.encoder.CRC().Write(p)
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}
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s.filling = append(s.filling, p...)
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return n + len(p), nil
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}
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add := p
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if len(p)+len(s.filling) > e.o.blockSize {
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add = add[:e.o.blockSize-len(s.filling)]
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}
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if e.o.crc {
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_, _ = s.encoder.CRC().Write(add)
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}
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s.filling = append(s.filling, add...)
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p = p[len(add):]
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n += len(add)
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if len(s.filling) < e.o.blockSize {
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return n, nil
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}
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err := e.nextBlock(false)
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if err != nil {
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return n, err
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}
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if debugAsserts && len(s.filling) > 0 {
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panic(len(s.filling))
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}
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}
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return n, nil
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}
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// nextBlock will synchronize and start compressing input in e.state.filling.
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// If an error has occurred during encoding it will be returned.
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func (e *Encoder) nextBlock(final bool) error {
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s := &e.state
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// Wait for current block.
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s.wg.Wait()
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if s.err != nil {
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return s.err
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}
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if len(s.filling) > e.o.blockSize {
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return fmt.Errorf("block > maxStoreBlockSize")
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}
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if !s.headerWritten {
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// If we have a single block encode, do a sync compression.
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if final && len(s.filling) == 0 && !e.o.fullZero {
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s.headerWritten = true
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s.fullFrameWritten = true
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s.eofWritten = true
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return nil
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}
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if final && len(s.filling) > 0 {
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s.current = e.EncodeAll(s.filling, s.current[:0])
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var n2 int
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n2, s.err = s.w.Write(s.current)
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if s.err != nil {
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return s.err
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}
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s.nWritten += int64(n2)
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s.nInput += int64(len(s.filling))
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s.current = s.current[:0]
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s.filling = s.filling[:0]
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s.headerWritten = true
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s.fullFrameWritten = true
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s.eofWritten = true
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return nil
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}
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var tmp [maxHeaderSize]byte
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fh := frameHeader{
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ContentSize: uint64(s.frameContentSize),
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WindowSize: uint32(s.encoder.WindowSize(s.frameContentSize)),
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SingleSegment: false,
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Checksum: e.o.crc,
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DictID: e.o.dict.ID(),
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}
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dst, err := fh.appendTo(tmp[:0])
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if err != nil {
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return err
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}
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s.headerWritten = true
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s.wWg.Wait()
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var n2 int
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n2, s.err = s.w.Write(dst)
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if s.err != nil {
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return s.err
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}
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s.nWritten += int64(n2)
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}
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if s.eofWritten {
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// Ensure we only write it once.
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final = false
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}
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if len(s.filling) == 0 {
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// Final block, but no data.
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if final {
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enc := s.encoder
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blk := enc.Block()
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blk.reset(nil)
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blk.last = true
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blk.encodeRaw(nil)
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s.wWg.Wait()
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_, s.err = s.w.Write(blk.output)
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s.nWritten += int64(len(blk.output))
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s.eofWritten = true
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}
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return s.err
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}
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2022-03-16 10:16:28 -04:00
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// SYNC:
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if e.o.concurrent == 1 {
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src := s.filling
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s.nInput += int64(len(s.filling))
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if debugEncoder {
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println("Adding sync block,", len(src), "bytes, final:", final)
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}
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enc := s.encoder
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blk := enc.Block()
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blk.reset(nil)
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enc.Encode(blk, src)
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blk.last = final
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if final {
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s.eofWritten = true
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}
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err := errIncompressible
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// If we got the exact same number of literals as input,
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// assume the literals cannot be compressed.
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if len(src) != len(blk.literals) || len(src) != e.o.blockSize {
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err = blk.encode(src, e.o.noEntropy, !e.o.allLitEntropy)
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}
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switch err {
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case errIncompressible:
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if debugEncoder {
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println("Storing incompressible block as raw")
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}
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blk.encodeRaw(src)
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// In fast mode, we do not transfer offsets, so we don't have to deal with changing the.
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case nil:
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default:
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s.err = err
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return err
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}
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_, s.err = s.w.Write(blk.output)
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s.nWritten += int64(len(blk.output))
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s.filling = s.filling[:0]
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return s.err
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}
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2022-03-03 08:19:41 -05:00
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// Move blocks forward.
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s.filling, s.current, s.previous = s.previous[:0], s.filling, s.current
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s.nInput += int64(len(s.current))
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s.wg.Add(1)
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go func(src []byte) {
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if debugEncoder {
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println("Adding block,", len(src), "bytes, final:", final)
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}
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defer func() {
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if r := recover(); r != nil {
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s.err = fmt.Errorf("panic while encoding: %v", r)
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rdebug.PrintStack()
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}
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s.wg.Done()
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}()
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enc := s.encoder
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blk := enc.Block()
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enc.Encode(blk, src)
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blk.last = final
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if final {
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s.eofWritten = true
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}
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// Wait for pending writes.
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s.wWg.Wait()
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if s.writeErr != nil {
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s.err = s.writeErr
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return
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}
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// Transfer encoders from previous write block.
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blk.swapEncoders(s.writing)
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// Transfer recent offsets to next.
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enc.UseBlock(s.writing)
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s.writing = blk
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s.wWg.Add(1)
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go func() {
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defer func() {
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if r := recover(); r != nil {
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s.writeErr = fmt.Errorf("panic while encoding/writing: %v", r)
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rdebug.PrintStack()
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}
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s.wWg.Done()
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}()
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err := errIncompressible
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// If we got the exact same number of literals as input,
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// assume the literals cannot be compressed.
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if len(src) != len(blk.literals) || len(src) != e.o.blockSize {
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err = blk.encode(src, e.o.noEntropy, !e.o.allLitEntropy)
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}
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switch err {
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case errIncompressible:
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if debugEncoder {
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println("Storing incompressible block as raw")
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}
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blk.encodeRaw(src)
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// In fast mode, we do not transfer offsets, so we don't have to deal with changing the.
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case nil:
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default:
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s.writeErr = err
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return
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}
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_, s.writeErr = s.w.Write(blk.output)
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s.nWritten += int64(len(blk.output))
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}()
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}(s.current)
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return nil
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}
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// ReadFrom reads data from r until EOF or error.
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// The return value n is the number of bytes read.
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// Any error except io.EOF encountered during the read is also returned.
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//
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// The Copy function uses ReaderFrom if available.
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func (e *Encoder) ReadFrom(r io.Reader) (n int64, err error) {
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if debugEncoder {
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println("Using ReadFrom")
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}
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// Flush any current writes.
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if len(e.state.filling) > 0 {
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if err := e.nextBlock(false); err != nil {
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return 0, err
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}
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}
|
|
|
|
e.state.filling = e.state.filling[:e.o.blockSize]
|
|
|
|
src := e.state.filling
|
|
|
|
for {
|
|
|
|
n2, err := r.Read(src)
|
|
|
|
if e.o.crc {
|
|
|
|
_, _ = e.state.encoder.CRC().Write(src[:n2])
|
|
|
|
}
|
|
|
|
// src is now the unfilled part...
|
|
|
|
src = src[n2:]
|
|
|
|
n += int64(n2)
|
|
|
|
switch err {
|
|
|
|
case io.EOF:
|
|
|
|
e.state.filling = e.state.filling[:len(e.state.filling)-len(src)]
|
|
|
|
if debugEncoder {
|
|
|
|
println("ReadFrom: got EOF final block:", len(e.state.filling))
|
|
|
|
}
|
|
|
|
return n, nil
|
|
|
|
case nil:
|
|
|
|
default:
|
|
|
|
if debugEncoder {
|
|
|
|
println("ReadFrom: got error:", err)
|
|
|
|
}
|
|
|
|
e.state.err = err
|
|
|
|
return n, err
|
|
|
|
}
|
|
|
|
if len(src) > 0 {
|
|
|
|
if debugEncoder {
|
|
|
|
println("ReadFrom: got space left in source:", len(src))
|
|
|
|
}
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
err = e.nextBlock(false)
|
|
|
|
if err != nil {
|
|
|
|
return n, err
|
|
|
|
}
|
|
|
|
e.state.filling = e.state.filling[:e.o.blockSize]
|
|
|
|
src = e.state.filling
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Flush will send the currently written data to output
|
|
|
|
// and block until everything has been written.
|
|
|
|
// This should only be used on rare occasions where pushing the currently queued data is critical.
|
|
|
|
func (e *Encoder) Flush() error {
|
|
|
|
s := &e.state
|
|
|
|
if len(s.filling) > 0 {
|
|
|
|
err := e.nextBlock(false)
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
}
|
|
|
|
s.wg.Wait()
|
|
|
|
s.wWg.Wait()
|
|
|
|
if s.err != nil {
|
|
|
|
return s.err
|
|
|
|
}
|
|
|
|
return s.writeErr
|
|
|
|
}
|
|
|
|
|
|
|
|
// Close will flush the final output and close the stream.
|
|
|
|
// The function will block until everything has been written.
|
|
|
|
// The Encoder can still be re-used after calling this.
|
|
|
|
func (e *Encoder) Close() error {
|
|
|
|
s := &e.state
|
|
|
|
if s.encoder == nil {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
err := e.nextBlock(true)
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if s.frameContentSize > 0 {
|
|
|
|
if s.nInput != s.frameContentSize {
|
|
|
|
return fmt.Errorf("frame content size %d given, but %d bytes was written", s.frameContentSize, s.nInput)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if e.state.fullFrameWritten {
|
|
|
|
return s.err
|
|
|
|
}
|
|
|
|
s.wg.Wait()
|
|
|
|
s.wWg.Wait()
|
|
|
|
|
|
|
|
if s.err != nil {
|
|
|
|
return s.err
|
|
|
|
}
|
|
|
|
if s.writeErr != nil {
|
|
|
|
return s.writeErr
|
|
|
|
}
|
|
|
|
|
|
|
|
// Write CRC
|
|
|
|
if e.o.crc && s.err == nil {
|
|
|
|
// heap alloc.
|
|
|
|
var tmp [4]byte
|
|
|
|
_, s.err = s.w.Write(s.encoder.AppendCRC(tmp[:0]))
|
|
|
|
s.nWritten += 4
|
|
|
|
}
|
|
|
|
|
|
|
|
// Add padding with content from crypto/rand.Reader
|
|
|
|
if s.err == nil && e.o.pad > 0 {
|
|
|
|
add := calcSkippableFrame(s.nWritten, int64(e.o.pad))
|
|
|
|
frame, err := skippableFrame(s.filling[:0], add, rand.Reader)
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
_, s.err = s.w.Write(frame)
|
|
|
|
}
|
|
|
|
return s.err
|
|
|
|
}
|
|
|
|
|
|
|
|
// EncodeAll will encode all input in src and append it to dst.
|
|
|
|
// This function can be called concurrently, but each call will only run on a single goroutine.
|
|
|
|
// If empty input is given, nothing is returned, unless WithZeroFrames is specified.
|
|
|
|
// Encoded blocks can be concatenated and the result will be the combined input stream.
|
|
|
|
// Data compressed with EncodeAll can be decoded with the Decoder,
|
|
|
|
// using either a stream or DecodeAll.
|
|
|
|
func (e *Encoder) EncodeAll(src, dst []byte) []byte {
|
|
|
|
if len(src) == 0 {
|
|
|
|
if e.o.fullZero {
|
|
|
|
// Add frame header.
|
|
|
|
fh := frameHeader{
|
|
|
|
ContentSize: 0,
|
|
|
|
WindowSize: MinWindowSize,
|
|
|
|
SingleSegment: true,
|
|
|
|
// Adding a checksum would be a waste of space.
|
|
|
|
Checksum: false,
|
|
|
|
DictID: 0,
|
|
|
|
}
|
|
|
|
dst, _ = fh.appendTo(dst)
|
|
|
|
|
|
|
|
// Write raw block as last one only.
|
|
|
|
var blk blockHeader
|
|
|
|
blk.setSize(0)
|
|
|
|
blk.setType(blockTypeRaw)
|
|
|
|
blk.setLast(true)
|
|
|
|
dst = blk.appendTo(dst)
|
|
|
|
}
|
|
|
|
return dst
|
|
|
|
}
|
|
|
|
e.init.Do(e.initialize)
|
|
|
|
enc := <-e.encoders
|
|
|
|
defer func() {
|
|
|
|
// Release encoder reference to last block.
|
|
|
|
// If a non-single block is needed the encoder will reset again.
|
|
|
|
e.encoders <- enc
|
|
|
|
}()
|
2022-09-10 12:50:02 -04:00
|
|
|
// Use single segments when above minimum window and below window size.
|
|
|
|
single := len(src) <= e.o.windowSize && len(src) > MinWindowSize
|
2022-03-03 08:19:41 -05:00
|
|
|
if e.o.single != nil {
|
|
|
|
single = *e.o.single
|
|
|
|
}
|
|
|
|
fh := frameHeader{
|
|
|
|
ContentSize: uint64(len(src)),
|
|
|
|
WindowSize: uint32(enc.WindowSize(int64(len(src)))),
|
|
|
|
SingleSegment: single,
|
|
|
|
Checksum: e.o.crc,
|
|
|
|
DictID: e.o.dict.ID(),
|
|
|
|
}
|
|
|
|
|
|
|
|
// If less than 1MB, allocate a buffer up front.
|
|
|
|
if len(dst) == 0 && cap(dst) == 0 && len(src) < 1<<20 && !e.o.lowMem {
|
|
|
|
dst = make([]byte, 0, len(src))
|
|
|
|
}
|
|
|
|
dst, err := fh.appendTo(dst)
|
|
|
|
if err != nil {
|
|
|
|
panic(err)
|
|
|
|
}
|
|
|
|
|
|
|
|
// If we can do everything in one block, prefer that.
|
2022-09-10 12:50:02 -04:00
|
|
|
if len(src) <= e.o.blockSize {
|
2022-03-03 08:19:41 -05:00
|
|
|
enc.Reset(e.o.dict, true)
|
|
|
|
// Slightly faster with no history and everything in one block.
|
|
|
|
if e.o.crc {
|
|
|
|
_, _ = enc.CRC().Write(src)
|
|
|
|
}
|
|
|
|
blk := enc.Block()
|
|
|
|
blk.last = true
|
|
|
|
if e.o.dict == nil {
|
|
|
|
enc.EncodeNoHist(blk, src)
|
|
|
|
} else {
|
|
|
|
enc.Encode(blk, src)
|
|
|
|
}
|
|
|
|
|
|
|
|
// If we got the exact same number of literals as input,
|
|
|
|
// assume the literals cannot be compressed.
|
|
|
|
err := errIncompressible
|
|
|
|
oldout := blk.output
|
|
|
|
if len(blk.literals) != len(src) || len(src) != e.o.blockSize {
|
|
|
|
// Output directly to dst
|
|
|
|
blk.output = dst
|
|
|
|
err = blk.encode(src, e.o.noEntropy, !e.o.allLitEntropy)
|
|
|
|
}
|
|
|
|
|
|
|
|
switch err {
|
|
|
|
case errIncompressible:
|
|
|
|
if debugEncoder {
|
|
|
|
println("Storing incompressible block as raw")
|
|
|
|
}
|
|
|
|
dst = blk.encodeRawTo(dst, src)
|
|
|
|
case nil:
|
|
|
|
dst = blk.output
|
|
|
|
default:
|
|
|
|
panic(err)
|
|
|
|
}
|
|
|
|
blk.output = oldout
|
|
|
|
} else {
|
|
|
|
enc.Reset(e.o.dict, false)
|
|
|
|
blk := enc.Block()
|
|
|
|
for len(src) > 0 {
|
|
|
|
todo := src
|
|
|
|
if len(todo) > e.o.blockSize {
|
|
|
|
todo = todo[:e.o.blockSize]
|
|
|
|
}
|
|
|
|
src = src[len(todo):]
|
|
|
|
if e.o.crc {
|
|
|
|
_, _ = enc.CRC().Write(todo)
|
|
|
|
}
|
|
|
|
blk.pushOffsets()
|
|
|
|
enc.Encode(blk, todo)
|
|
|
|
if len(src) == 0 {
|
|
|
|
blk.last = true
|
|
|
|
}
|
|
|
|
err := errIncompressible
|
|
|
|
// If we got the exact same number of literals as input,
|
|
|
|
// assume the literals cannot be compressed.
|
|
|
|
if len(blk.literals) != len(todo) || len(todo) != e.o.blockSize {
|
|
|
|
err = blk.encode(todo, e.o.noEntropy, !e.o.allLitEntropy)
|
|
|
|
}
|
|
|
|
|
|
|
|
switch err {
|
|
|
|
case errIncompressible:
|
|
|
|
if debugEncoder {
|
|
|
|
println("Storing incompressible block as raw")
|
|
|
|
}
|
|
|
|
dst = blk.encodeRawTo(dst, todo)
|
|
|
|
blk.popOffsets()
|
|
|
|
case nil:
|
|
|
|
dst = append(dst, blk.output...)
|
|
|
|
default:
|
|
|
|
panic(err)
|
|
|
|
}
|
|
|
|
blk.reset(nil)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if e.o.crc {
|
|
|
|
dst = enc.AppendCRC(dst)
|
|
|
|
}
|
|
|
|
// Add padding with content from crypto/rand.Reader
|
|
|
|
if e.o.pad > 0 {
|
|
|
|
add := calcSkippableFrame(int64(len(dst)), int64(e.o.pad))
|
|
|
|
dst, err = skippableFrame(dst, add, rand.Reader)
|
|
|
|
if err != nil {
|
|
|
|
panic(err)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return dst
|
|
|
|
}
|
2023-03-28 10:43:43 -04:00
|
|
|
|
|
|
|
// MaxEncodedSize returns the expected maximum
|
|
|
|
// size of an encoded block or stream.
|
|
|
|
func (e *Encoder) MaxEncodedSize(size int) int {
|
|
|
|
frameHeader := 4 + 2 // magic + frame header & window descriptor
|
|
|
|
if e.o.dict != nil {
|
|
|
|
frameHeader += 4
|
|
|
|
}
|
|
|
|
// Frame content size:
|
|
|
|
if size < 256 {
|
|
|
|
frameHeader++
|
|
|
|
} else if size < 65536+256 {
|
|
|
|
frameHeader += 2
|
|
|
|
} else if size < math.MaxInt32 {
|
|
|
|
frameHeader += 4
|
|
|
|
} else {
|
|
|
|
frameHeader += 8
|
|
|
|
}
|
|
|
|
// Final crc
|
|
|
|
if e.o.crc {
|
|
|
|
frameHeader += 4
|
|
|
|
}
|
|
|
|
|
|
|
|
// Max overhead is 3 bytes/block.
|
|
|
|
// There cannot be 0 blocks.
|
|
|
|
blocks := (size + e.o.blockSize) / e.o.blockSize
|
|
|
|
|
|
|
|
// Combine, add padding.
|
|
|
|
maxSz := frameHeader + 3*blocks + size
|
|
|
|
if e.o.pad > 1 {
|
|
|
|
maxSz += calcSkippableFrame(int64(maxSz), int64(e.o.pad))
|
|
|
|
}
|
|
|
|
return maxSz
|
|
|
|
}
|