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-rw-r--r--vendor/github.com/klauspost/compress/zstd/blockdec.go708
1 files changed, 708 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/blockdec.go b/vendor/github.com/klauspost/compress/zstd/blockdec.go
new file mode 100644
index 000000000..aca1cb85d
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/blockdec.go
@@ -0,0 +1,708 @@
+// 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 (
+ "errors"
+ "fmt"
+ "io"
+ "sync"
+
+ "github.com/klauspost/compress/huff0"
+)
+
+type blockType uint8
+
+//go:generate stringer -type=blockType,literalsBlockType,seqCompMode,tableIndex
+
+const (
+ blockTypeRaw blockType = iota
+ blockTypeRLE
+ blockTypeCompressed
+ blockTypeReserved
+)
+
+type literalsBlockType uint8
+
+const (
+ literalsBlockRaw literalsBlockType = iota
+ literalsBlockRLE
+ literalsBlockCompressed
+ literalsBlockTreeless
+)
+
+const (
+ // maxCompressedBlockSize is the biggest allowed compressed block size (128KB)
+ maxCompressedBlockSize = 128 << 10
+
+ // Maximum possible block size (all Raw+Uncompressed).
+ maxBlockSize = (1 << 21) - 1
+
+ // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#literals_section_header
+ maxCompressedLiteralSize = 1 << 18
+ maxRLELiteralSize = 1 << 20
+ maxMatchLen = 131074
+ maxSequences = 0x7f00 + 0xffff
+
+ // We support slightly less than the reference decoder to be able to
+ // use ints on 32 bit archs.
+ maxOffsetBits = 30
+)
+
+var (
+ huffDecoderPool = sync.Pool{New: func() interface{} {
+ return &huff0.Scratch{}
+ }}
+
+ fseDecoderPool = sync.Pool{New: func() interface{} {
+ return &fseDecoder{}
+ }}
+)
+
+type blockDec struct {
+ // Raw source data of the block.
+ data []byte
+
+ // Destination of the decoded data.
+ dst []byte
+
+ // Buffer for literals data.
+ literalBuf []byte
+
+ // Window size of the block.
+ WindowSize uint64
+ Type blockType
+ RLESize uint32
+
+ // Is this the last block of a frame?
+ Last bool
+
+ // Use less memory
+ lowMem bool
+ history chan *history
+ input chan struct{}
+ result chan decodeOutput
+ sequenceBuf []seq
+ tmp [4]byte
+ err error
+}
+
+func (b *blockDec) String() string {
+ if b == nil {
+ return "<nil>"
+ }
+ return fmt.Sprintf("Steam Size: %d, Type: %v, Last: %t, Window: %d", len(b.data), b.Type, b.Last, b.WindowSize)
+}
+
+func newBlockDec(lowMem bool) *blockDec {
+ b := blockDec{
+ lowMem: lowMem,
+ result: make(chan decodeOutput, 1),
+ input: make(chan struct{}, 1),
+ history: make(chan *history, 1),
+ }
+ go b.startDecoder()
+ return &b
+}
+
+// reset will reset the block.
+// Input must be a start of a block and will be at the end of the block when returned.
+func (b *blockDec) reset(br byteBuffer, windowSize uint64) error {
+ b.WindowSize = windowSize
+ tmp := br.readSmall(3)
+ if tmp == nil {
+ if debug {
+ println("Reading block header:", io.ErrUnexpectedEOF)
+ }
+ return io.ErrUnexpectedEOF
+ }
+ bh := uint32(tmp[0]) | (uint32(tmp[1]) << 8) | (uint32(tmp[2]) << 16)
+ b.Last = bh&1 != 0
+ b.Type = blockType((bh >> 1) & 3)
+ // find size.
+ cSize := int(bh >> 3)
+ switch b.Type {
+ case blockTypeReserved:
+ return ErrReservedBlockType
+ case blockTypeRLE:
+ b.RLESize = uint32(cSize)
+ cSize = 1
+ case blockTypeCompressed:
+ if debug {
+ println("Data size on stream:", cSize)
+ }
+ b.RLESize = 0
+ if cSize > maxCompressedBlockSize || uint64(cSize) > b.WindowSize {
+ if debug {
+ printf("compressed block too big: csize:%d block: %+v\n", uint64(cSize), b)
+ }
+ return ErrCompressedSizeTooBig
+ }
+ default:
+ b.RLESize = 0
+ }
+
+ // Read block data.
+ if cap(b.data) < cSize {
+ if b.lowMem {
+ b.data = make([]byte, 0, cSize)
+ } else {
+ b.data = make([]byte, 0, maxBlockSize)
+ }
+ }
+ if cap(b.dst) <= maxBlockSize {
+ b.dst = make([]byte, 0, maxBlockSize+1)
+ }
+ var err error
+ b.data, err = br.readBig(cSize, b.data[:0])
+ if err != nil {
+ if debug {
+ println("Reading block:", err)
+ }
+ return err
+ }
+ return nil
+}
+
+// sendEOF will make the decoder send EOF on this frame.
+func (b *blockDec) sendErr(err error) {
+ b.Last = true
+ b.Type = blockTypeReserved
+ b.err = err
+ b.input <- struct{}{}
+}
+
+// Close will release resources.
+// Closed blockDec cannot be reset.
+func (b *blockDec) Close() {
+ close(b.input)
+ close(b.history)
+ close(b.result)
+}
+
+// decodeAsync will prepare decoding the block when it receives input.
+// This will separate output and history.
+func (b *blockDec) startDecoder() {
+ for range b.input {
+ //println("blockDec: Got block input")
+ switch b.Type {
+ case blockTypeRLE:
+ if cap(b.dst) < int(b.RLESize) {
+ if b.lowMem {
+ b.dst = make([]byte, b.RLESize)
+ } else {
+ b.dst = make([]byte, maxBlockSize)
+ }
+ }
+ o := decodeOutput{
+ d: b,
+ b: b.dst[:b.RLESize],
+ err: nil,
+ }
+ v := b.data[0]
+ for i := range o.b {
+ o.b[i] = v
+ }
+ hist := <-b.history
+ hist.append(o.b)
+ b.result <- o
+ case blockTypeRaw:
+ o := decodeOutput{
+ d: b,
+ b: b.data,
+ err: nil,
+ }
+ hist := <-b.history
+ hist.append(o.b)
+ b.result <- o
+ case blockTypeCompressed:
+ b.dst = b.dst[:0]
+ err := b.decodeCompressed(nil)
+ o := decodeOutput{
+ d: b,
+ b: b.dst,
+ err: err,
+ }
+ if debug {
+ println("Decompressed to", len(b.dst), "bytes, error:", err)
+ }
+ b.result <- o
+ case blockTypeReserved:
+ // Used for returning errors.
+ <-b.history
+ b.result <- decodeOutput{
+ d: b,
+ b: nil,
+ err: b.err,
+ }
+ default:
+ panic("Invalid block type")
+ }
+ if debug {
+ println("blockDec: Finished block")
+ }
+ }
+}
+
+// decodeAsync will prepare decoding the block when it receives the history.
+// If history is provided, it will not fetch it from the channel.
+func (b *blockDec) decodeBuf(hist *history) error {
+ switch b.Type {
+ case blockTypeRLE:
+ if cap(b.dst) < int(b.RLESize) {
+ if b.lowMem {
+ b.dst = make([]byte, b.RLESize)
+ } else {
+ b.dst = make([]byte, maxBlockSize)
+ }
+ }
+ b.dst = b.dst[:b.RLESize]
+ v := b.data[0]
+ for i := range b.dst {
+ b.dst[i] = v
+ }
+ hist.appendKeep(b.dst)
+ return nil
+ case blockTypeRaw:
+ hist.appendKeep(b.data)
+ return nil
+ case blockTypeCompressed:
+ saved := b.dst
+ b.dst = hist.b
+ hist.b = nil
+ err := b.decodeCompressed(hist)
+ if debug {
+ println("Decompressed to total", len(b.dst), "bytes, error:", err)
+ }
+ hist.b = b.dst
+ b.dst = saved
+ return err
+ case blockTypeReserved:
+ // Used for returning errors.
+ return b.err
+ default:
+ panic("Invalid block type")
+ }
+}
+
+// decodeCompressed will start decompressing a block.
+// If no history is supplied the decoder will decodeAsync as much as possible
+// before fetching from blockDec.history
+func (b *blockDec) decodeCompressed(hist *history) error {
+ in := b.data
+ delayedHistory := hist == nil
+
+ if delayedHistory {
+ // We must always grab history.
+ defer func() {
+ if hist == nil {
+ <-b.history
+ }
+ }()
+ }
+ // There must be at least one byte for Literals_Block_Type and one for Sequences_Section_Header
+ if len(in) < 2 {
+ return ErrBlockTooSmall
+ }
+ litType := literalsBlockType(in[0] & 3)
+ var litRegenSize int
+ var litCompSize int
+ sizeFormat := (in[0] >> 2) & 3
+ var fourStreams bool
+ switch litType {
+ case literalsBlockRaw, literalsBlockRLE:
+ switch sizeFormat {
+ case 0, 2:
+ // Regenerated_Size uses 5 bits (0-31). Literals_Section_Header uses 1 byte.
+ litRegenSize = int(in[0] >> 3)
+ in = in[1:]
+ case 1:
+ // Regenerated_Size uses 12 bits (0-4095). Literals_Section_Header uses 2 bytes.
+ litRegenSize = int(in[0]>>4) + (int(in[1]) << 4)
+ in = in[2:]
+ case 3:
+ // Regenerated_Size uses 20 bits (0-1048575). Literals_Section_Header uses 3 bytes.
+ if len(in) < 3 {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, len(in))
+ return ErrBlockTooSmall
+ }
+ litRegenSize = int(in[0]>>4) + (int(in[1]) << 4) + (int(in[2]) << 12)
+ in = in[3:]
+ }
+ case literalsBlockCompressed, literalsBlockTreeless:
+ switch sizeFormat {
+ case 0, 1:
+ // Both Regenerated_Size and Compressed_Size use 10 bits (0-1023).
+ if len(in) < 3 {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, len(in))
+ return ErrBlockTooSmall
+ }
+ n := uint64(in[0]>>4) + (uint64(in[1]) << 4) + (uint64(in[2]) << 12)
+ litRegenSize = int(n & 1023)
+ litCompSize = int(n >> 10)
+ fourStreams = sizeFormat == 1
+ in = in[3:]
+ case 2:
+ fourStreams = true
+ if len(in) < 4 {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, len(in))
+ return ErrBlockTooSmall
+ }
+ n := uint64(in[0]>>4) + (uint64(in[1]) << 4) + (uint64(in[2]) << 12) + (uint64(in[3]) << 20)
+ litRegenSize = int(n & 16383)
+ litCompSize = int(n >> 14)
+ in = in[4:]
+ case 3:
+ fourStreams = true
+ if len(in) < 5 {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, len(in))
+ return ErrBlockTooSmall
+ }
+ n := uint64(in[0]>>4) + (uint64(in[1]) << 4) + (uint64(in[2]) << 12) + (uint64(in[3]) << 20) + (uint64(in[4]) << 28)
+ litRegenSize = int(n & 262143)
+ litCompSize = int(n >> 18)
+ in = in[5:]
+ }
+ }
+ if debug {
+ println("literals type:", litType, "litRegenSize:", litRegenSize, "litCompSize", litCompSize)
+ }
+ var literals []byte
+ var huff *huff0.Scratch
+ switch litType {
+ case literalsBlockRaw:
+ if len(in) < litRegenSize {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", litRegenSize)
+ return ErrBlockTooSmall
+ }
+ literals = in[:litRegenSize]
+ in = in[litRegenSize:]
+ //printf("Found %d uncompressed literals\n", litRegenSize)
+ case literalsBlockRLE:
+ if len(in) < 1 {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", 1)
+ return ErrBlockTooSmall
+ }
+ if cap(b.literalBuf) < litRegenSize {
+ if b.lowMem {
+ b.literalBuf = make([]byte, litRegenSize)
+ } else {
+ if litRegenSize > maxCompressedLiteralSize {
+ // Exceptional
+ b.literalBuf = make([]byte, litRegenSize)
+ } else {
+ b.literalBuf = make([]byte, litRegenSize, maxCompressedLiteralSize)
+
+ }
+ }
+ }
+ literals = b.literalBuf[:litRegenSize]
+ v := in[0]
+ for i := range literals {
+ literals[i] = v
+ }
+ in = in[1:]
+ if debug {
+ printf("Found %d RLE compressed literals\n", litRegenSize)
+ }
+ case literalsBlockTreeless:
+ if len(in) < litCompSize {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", litCompSize)
+ return ErrBlockTooSmall
+ }
+ // Store compressed literals, so we defer decoding until we get history.
+ literals = in[:litCompSize]
+ in = in[litCompSize:]
+ if debug {
+ printf("Found %d compressed literals\n", litCompSize)
+ }
+ case literalsBlockCompressed:
+ if len(in) < litCompSize {
+ println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", litCompSize)
+ return ErrBlockTooSmall
+ }
+ literals = in[:litCompSize]
+ in = in[litCompSize:]
+
+ huff = huffDecoderPool.Get().(*huff0.Scratch)
+ var err error
+ // Ensure we have space to store it.
+ if cap(b.literalBuf) < litRegenSize {
+ if b.lowMem {
+ b.literalBuf = make([]byte, 0, litRegenSize)
+ } else {
+ b.literalBuf = make([]byte, 0, maxCompressedLiteralSize)
+ }
+ }
+ if huff == nil {
+ huff = &huff0.Scratch{}
+ }
+ huff.Out = b.literalBuf[:0]
+ huff, literals, err = huff0.ReadTable(literals, huff)
+ if err != nil {
+ println("reading huffman table:", err)
+ return err
+ }
+ // Use our out buffer.
+ huff.Out = b.literalBuf[:0]
+ if fourStreams {
+ literals, err = huff.Decompress4X(literals, litRegenSize)
+ } else {
+ literals, err = huff.Decompress1X(literals)
+ }
+ if err != nil {
+ println("decoding compressed literals:", err)
+ return err
+ }
+ // Make sure we don't leak our literals buffer
+ huff.Out = nil
+ if len(literals) != litRegenSize {
+ return fmt.Errorf("literal output size mismatch want %d, got %d", litRegenSize, len(literals))
+ }
+ if debug {
+ printf("Decompressed %d literals into %d bytes\n", litCompSize, litRegenSize)
+ }
+ }
+
+ // Decode Sequences
+ // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#sequences-section
+ if len(in) < 1 {
+ return ErrBlockTooSmall
+ }
+ seqHeader := in[0]
+ nSeqs := 0
+ switch {
+ case seqHeader == 0:
+ in = in[1:]
+ case seqHeader < 128:
+ nSeqs = int(seqHeader)
+ in = in[1:]
+ case seqHeader < 255:
+ if len(in) < 2 {
+ return ErrBlockTooSmall
+ }
+ nSeqs = int(seqHeader-128)<<8 | int(in[1])
+ in = in[2:]
+ case seqHeader == 255:
+ if len(in) < 3 {
+ return ErrBlockTooSmall
+ }
+ nSeqs = 0x7f00 + int(in[1]) + (int(in[2]) << 8)
+ in = in[3:]
+ }
+ // Allocate sequences
+ if cap(b.sequenceBuf) < nSeqs {
+ if b.lowMem {
+ b.sequenceBuf = make([]seq, nSeqs)
+ } else {
+ // Allocate max
+ b.sequenceBuf = make([]seq, nSeqs, maxSequences)
+ }
+ } else {
+ // Reuse buffer
+ b.sequenceBuf = b.sequenceBuf[:nSeqs]
+ }
+ var seqs = &sequenceDecs{}
+ if nSeqs > 0 {
+ if len(in) < 1 {
+ return ErrBlockTooSmall
+ }
+ br := byteReader{b: in, off: 0}
+ compMode := br.Uint8()
+ br.advance(1)
+ if debug {
+ printf("Compression modes: 0b%b", compMode)
+ }
+ for i := uint(0); i < 3; i++ {
+ mode := seqCompMode((compMode >> (6 - i*2)) & 3)
+ if debug {
+ println("Table", tableIndex(i), "is", mode)
+ }
+ var seq *sequenceDec
+ switch tableIndex(i) {
+ case tableLiteralLengths:
+ seq = &seqs.litLengths
+ case tableOffsets:
+ seq = &seqs.offsets
+ case tableMatchLengths:
+ seq = &seqs.matchLengths
+ default:
+ panic("unknown table")
+ }
+ switch mode {
+ case compModePredefined:
+ seq.fse = &fsePredef[i]
+ case compModeRLE:
+ if br.remain() < 1 {
+ return ErrBlockTooSmall
+ }
+ v := br.Uint8()
+ br.advance(1)
+ dec := fseDecoderPool.Get().(*fseDecoder)
+ symb, err := decSymbolValue(v, symbolTableX[i])
+ if err != nil {
+ printf("RLE Transform table (%v) error: %v", tableIndex(i), err)
+ return err
+ }
+ dec.setRLE(symb)
+ seq.fse = dec
+ if debug {
+ printf("RLE set to %+v, code: %v", symb, v)
+ }
+ case compModeFSE:
+ println("Reading table for", tableIndex(i))
+ dec := fseDecoderPool.Get().(*fseDecoder)
+ err := dec.readNCount(&br, uint16(maxTableSymbol[i]))
+ if err != nil {
+ println("Read table error:", err)
+ return err
+ }
+ err = dec.transform(symbolTableX[i])
+ if err != nil {
+ println("Transform table error:", err)
+ return err
+ }
+ if debug {
+ println("Read table ok", "symbolLen:", dec.symbolLen)
+ }
+ seq.fse = dec
+ case compModeRepeat:
+ seq.repeat = true
+ }
+ if br.overread() {
+ return io.ErrUnexpectedEOF
+ }
+ }
+ in = br.unread()
+ }
+
+ // Wait for history.
+ // All time spent after this is critical since it is strictly sequential.
+ if hist == nil {
+ hist = <-b.history
+ if hist.error {
+ return ErrDecoderClosed
+ }
+ }
+
+ // Decode treeless literal block.
+ if litType == literalsBlockTreeless {
+ // TODO: We could send the history early WITHOUT the stream history.
+ // This would allow decoding treeless literials before the byte history is available.
+ // Silencia stats: Treeless 4393, with: 32775, total: 37168, 11% treeless.
+ // So not much obvious gain here.
+
+ if hist.huffTree == nil {
+ return errors.New("literal block was treeless, but no history was defined")
+ }
+ // Ensure we have space to store it.
+ if cap(b.literalBuf) < litRegenSize {
+ if b.lowMem {
+ b.literalBuf = make([]byte, 0, litRegenSize)
+ } else {
+ b.literalBuf = make([]byte, 0, maxCompressedLiteralSize)
+ }
+ }
+ var err error
+ // Use our out buffer.
+ huff = hist.huffTree
+ huff.Out = b.literalBuf[:0]
+ if fourStreams {
+ literals, err = huff.Decompress4X(literals, litRegenSize)
+ } else {
+ literals, err = huff.Decompress1X(literals)
+ }
+ // Make sure we don't leak our literals buffer
+ huff.Out = nil
+ if err != nil {
+ println("decompressing literals:", err)
+ return err
+ }
+ if len(literals) != litRegenSize {
+ return fmt.Errorf("literal output size mismatch want %d, got %d", litRegenSize, len(literals))
+ }
+ } else {
+ if hist.huffTree != nil && huff != nil {
+ huffDecoderPool.Put(hist.huffTree)
+ hist.huffTree = nil
+ }
+ }
+ if huff != nil {
+ huff.Out = nil
+ hist.huffTree = huff
+ }
+ if debug {
+ println("Final literals:", len(literals), "and", nSeqs, "sequences.")
+ }
+
+ if nSeqs == 0 {
+ // Decompressed content is defined entirely as Literals Section content.
+ b.dst = append(b.dst, literals...)
+ if delayedHistory {
+ hist.append(literals)
+ }
+ return nil
+ }
+
+ seqs, err := seqs.mergeHistory(&hist.decoders)
+ if err != nil {
+ return err
+ }
+ if debug {
+ println("History merged ok")
+ }
+ br := &bitReader{}
+ if err := br.init(in); err != nil {
+ return err
+ }
+
+ // TODO: Investigate if sending history without decoders are faster.
+ // This would allow the sequences to be decoded async and only have to construct stream history.
+ // If only recent offsets were not transferred, this would be an obvious win.
+ // Also, if first 3 sequences don't reference recent offsets, all sequences can be decoded.
+
+ if err := seqs.initialize(br, hist, literals, b.dst); err != nil {
+ println("initializing sequences:", err)
+ return err
+ }
+
+ err = seqs.decode(nSeqs, br, hist.b)
+ if err != nil {
+ return err
+ }
+ if !br.finished() {
+ return fmt.Errorf("%d extra bits on block, should be 0", br.remain())
+ }
+
+ err = br.close()
+ if err != nil {
+ printf("Closing sequences: %v, %+v\n", err, *br)
+ }
+ if len(b.data) > maxCompressedBlockSize {
+ return fmt.Errorf("compressed block size too large (%d)", len(b.data))
+ }
+ // Set output and release references.
+ b.dst = seqs.out
+ seqs.out, seqs.literals, seqs.hist = nil, nil, nil
+
+ if !delayedHistory {
+ // If we don't have delayed history, no need to update.
+ hist.recentOffsets = seqs.prevOffset
+ return nil
+ }
+ if b.Last {
+ // if last block we don't care about history.
+ println("Last block, no history returned")
+ hist.b = hist.b[:0]
+ return nil
+ }
+ hist.append(b.dst)
+ hist.recentOffsets = seqs.prevOffset
+ if debug {
+ println("Finished block with literals:", len(literals), "and", nSeqs, "sequences.")
+ }
+
+ return nil
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-11-17 10:23:47 +0000