Update dependencies (#1800)

16 files changed, 1246 insertions, 688 deletions

diff --git a/vendor/github.com/klauspost/compress/zstd/README.md b/vendor/github.com/klauspost/compress/zstd/README.md
index c8f0f16f..e3445ac1 100644
--- a/vendor/github.com/klauspost/compress/zstd/README.md
+++ b/vendor/github.com/klauspost/compress/zstd/README.md
@@ -78,6 +78,9 @@ of a stream. This is independent of the `WithEncoderConcurrency(n)`, but that is
 in the future. So if you want to limit concurrency for future updates, specify the concurrency
 you would like.
 
+If you would like stream encoding to be done without spawning async goroutines, use `WithEncoderConcurrency(1)`
+which will compress input as each block is completed, blocking on writes until each has completed.
+
 You can specify your desired compression level using `WithEncoderLevel()` option. Currently only pre-defined 
 compression settings can be specified.
 
@@ -104,7 +107,8 @@ and seems to ignore concatenated streams, even though [it is part of the spec](h
 For compressing small blocks, the returned encoder has a function called `EncodeAll(src, dst []byte) []byte`.
 
 `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.
+This function can be called concurrently. 
+Each call will only run on a same goroutine as the caller.
 
 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`.
@@ -149,10 +153,10 @@ http://sun.aei.polsl.pl/~sdeor/corpus/silesia.zip
 
 This package:
 file    out     level   insize      outsize     millis  mb/s
-silesia.tar zskp    1   211947520   73101992    643     313.87
-silesia.tar zskp    2   211947520   67504318    969     208.38
-silesia.tar zskp    3   211947520   64595893    2007    100.68
-silesia.tar zskp    4   211947520   60995370    8825    22.90
+silesia.tar zskp    1   211947520   73821326    634     318.47
+silesia.tar zskp    2   211947520   67655404    1508    133.96
+silesia.tar zskp    3   211947520   64746933    3000    67.37
+silesia.tar zskp    4   211947520   60073508    16926   11.94
 
 cgo zstd:
 silesia.tar zstd    1   211947520   73605392    543     371.56
@@ -161,94 +165,94 @@ silesia.tar zstd    6   211947520   62916450    1913    105.66
 silesia.tar zstd    9   211947520   60212393    5063    39.92
 
 gzip, stdlib/this package:
-silesia.tar gzstd   1   211947520   80007735    1654    122.21
-silesia.tar gzkp    1   211947520   80136201    1152    175.45
+silesia.tar gzstd   1   211947520   80007735    1498    134.87
+silesia.tar gzkp    1   211947520   80088272    1009    200.31
 
 GOB stream of binary data. Highly compressible.
 https://files.klauspost.com/compress/gob-stream.7z
 
 file        out     level   insize  outsize     millis  mb/s
-gob-stream  zskp    1   1911399616  235022249   3088    590.30
-gob-stream  zskp    2   1911399616  205669791   3786    481.34
-gob-stream  zskp    3   1911399616  175034659   9636    189.17
-gob-stream  zskp    4   1911399616  165609838   50369   36.19
+gob-stream  zskp    1   1911399616  233948096   3230    564.34
+gob-stream  zskp    2   1911399616  203997694   4997    364.73
+gob-stream  zskp    3   1911399616  173526523   13435   135.68
+gob-stream  zskp    4   1911399616  162195235   47559   38.33
 
 gob-stream  zstd    1   1911399616  249810424   2637    691.26
 gob-stream  zstd    3   1911399616  208192146   3490    522.31
 gob-stream  zstd    6   1911399616  193632038   6687    272.56
 gob-stream  zstd    9   1911399616  177620386   16175   112.70
 
-gob-stream  gzstd   1   1911399616  357382641   10251   177.82
-gob-stream  gzkp    1   1911399616  359753026   5438    335.20
+gob-stream  gzstd   1   1911399616  357382013   9046    201.49
+gob-stream  gzkp    1   1911399616  359136669   4885    373.08
 
 The test data for the Large Text Compression Benchmark is the first
 10^9 bytes of the English Wikipedia dump on Mar. 3, 2006.
 http://mattmahoney.net/dc/textdata.html
 
 file    out level   insize      outsize     millis  mb/s
-enwik9  zskp    1   1000000000  343848582   3609    264.18
-enwik9  zskp    2   1000000000  317276632   5746    165.97
-enwik9  zskp    3   1000000000  292243069   12162   78.41
-enwik9  zskp    4   1000000000  262183768   82837   11.51
+enwik9  zskp    1   1000000000  343833605   3687    258.64
+enwik9  zskp    2   1000000000  317001237   7672    124.29
+enwik9  zskp    3   1000000000  291915823   15923   59.89
+enwik9  zskp    4   1000000000  261710291   77697   12.27
 
 enwik9  zstd    1   1000000000  358072021   3110    306.65
 enwik9  zstd    3   1000000000  313734672   4784    199.35
 enwik9  zstd    6   1000000000  295138875   10290   92.68
 enwik9  zstd    9   1000000000  278348700   28549   33.40
 
-enwik9  gzstd   1   1000000000  382578136   9604    99.30
-enwik9  gzkp    1   1000000000  383825945   6544    145.73
+enwik9  gzstd   1   1000000000  382578136   8608    110.78
+enwik9  gzkp    1   1000000000  382781160   5628    169.45
 
 Highly compressible JSON file.
 https://files.klauspost.com/compress/github-june-2days-2019.json.zst
 
 file                        out level   insize      outsize     millis  mb/s
-github-june-2days-2019.json zskp    1   6273951764  699045015   10620   563.40
-github-june-2days-2019.json zskp    2   6273951764  617881763   11687   511.96
-github-june-2days-2019.json zskp    3   6273951764  524340691   34043   175.75
-github-june-2days-2019.json zskp    4   6273951764  470320075   170190  35.16
+github-june-2days-2019.json zskp    1   6273951764  697439532   9789    611.17
+github-june-2days-2019.json zskp    2   6273951764  610876538   18553   322.49
+github-june-2days-2019.json zskp    3   6273951764  517662858   44186   135.41
+github-june-2days-2019.json zskp    4   6273951764  464617114   165373  36.18
 
 github-june-2days-2019.json zstd    1   6273951764  766284037   8450    708.00
 github-june-2days-2019.json zstd    3   6273951764  661889476   10927   547.57
 github-june-2days-2019.json zstd    6   6273951764  642756859   22996   260.18
 github-june-2days-2019.json zstd    9   6273951764  601974523   52413   114.16
 
-github-june-2days-2019.json gzstd   1   6273951764  1164400847  29948   199.79
-github-june-2days-2019.json gzkp    1   6273951764  1125417694  21788   274.61
+github-june-2days-2019.json gzstd   1   6273951764  1164397768  26793   223.32
+github-june-2days-2019.json gzkp    1   6273951764  1120631856  17693   338.16
 
 VM Image, Linux mint with a few installed applications:
 https://files.klauspost.com/compress/rawstudio-mint14.7z
 
 file                    out level   insize      outsize     millis  mb/s
-rawstudio-mint14.tar    zskp    1   8558382592  3667489370  20210   403.84
-rawstudio-mint14.tar    zskp    2   8558382592  3364592300  31873   256.07
-rawstudio-mint14.tar    zskp    3   8558382592  3158085214  77675   105.08
-rawstudio-mint14.tar    zskp    4   8558382592  2965110639  857750  9.52
+rawstudio-mint14.tar    zskp    1   8558382592  3718400221  18206   448.29
+rawstudio-mint14.tar    zskp    2   8558382592  3326118337  37074   220.15
+rawstudio-mint14.tar    zskp    3   8558382592  3163842361  87306   93.49
+rawstudio-mint14.tar    zskp    4   8558382592  2970480650  783862  10.41
 
 rawstudio-mint14.tar    zstd    1   8558382592  3609250104  17136   476.27
 rawstudio-mint14.tar    zstd    3   8558382592  3341679997  29262   278.92
 rawstudio-mint14.tar    zstd    6   8558382592  3235846406  77904   104.77
 rawstudio-mint14.tar    zstd    9   8558382592  3160778861  140946  57.91
 
-rawstudio-mint14.tar    gzstd   1   8558382592  3926257486  57722   141.40
-rawstudio-mint14.tar    gzkp    1   8558382592  3962605659  45113   180.92
+rawstudio-mint14.tar    gzstd   1   8558382592  3926234992  51345   158.96
+rawstudio-mint14.tar    gzkp    1   8558382592  3960117298  36722   222.26
 
 CSV data:
 https://files.klauspost.com/compress/nyc-taxi-data-10M.csv.zst
 
 file                    out level   insize      outsize     millis  mb/s
-nyc-taxi-data-10M.csv   zskp    1   3325605752  641339945   8925    355.35
-nyc-taxi-data-10M.csv   zskp    2   3325605752  591748091   11268   281.44
-nyc-taxi-data-10M.csv   zskp    3   3325605752  530289687   25239   125.66
-nyc-taxi-data-10M.csv   zskp    4   3325605752  476268884   135958  23.33
+nyc-taxi-data-10M.csv   zskp    1   3325605752  641319332   9462    335.17
+nyc-taxi-data-10M.csv   zskp    2   3325605752  588976126   17570   180.50
+nyc-taxi-data-10M.csv   zskp    3   3325605752  529329260   32432   97.79
+nyc-taxi-data-10M.csv   zskp    4   3325605752  474949772   138025  22.98
 
 nyc-taxi-data-10M.csv   zstd    1   3325605752  687399637   8233    385.18
 nyc-taxi-data-10M.csv   zstd    3   3325605752  598514411   10065   315.07
 nyc-taxi-data-10M.csv   zstd    6   3325605752  570522953   20038   158.27
 nyc-taxi-data-10M.csv   zstd    9   3325605752  517554797   64565   49.12
 
-nyc-taxi-data-10M.csv   gzstd   1   3325605752  928656485   23876   132.83
-nyc-taxi-data-10M.csv   gzkp    1   3325605752  922257165   16780   189.00
+nyc-taxi-data-10M.csv   gzstd   1   3325605752  928654908   21270   149.11
+nyc-taxi-data-10M.csv   gzkp    1   3325605752  922273214   13929   227.68
 ```
 
 ## Decompressor
@@ -283,8 +287,13 @@ func Decompress(in io.Reader, out io.Writer) error {
 }
 ```
 
-It is important to use the "Close" function when you no longer need the Reader to stop running goroutines. 
-See "Allocation-less operation" below.
+It is important to use the "Close" function when you no longer need the Reader to stop running goroutines, 
+when running with default settings.
+Goroutines will exit once an error has been returned, including `io.EOF` at the end of a stream.
+
+Streams are decoded concurrently in 4 asynchronous stages to give the best possible throughput.
+However, if you prefer synchronous decompression, use `WithDecoderConcurrency(1)` which will decompress data 
+as it is being requested only.
 
 For decoding buffers, it could look something like this:
 
@@ -293,7 +302,7 @@ import "github.com/klauspost/compress/zstd"
 
 // Create a reader that caches decompressors.
 // For this operation type we supply a nil Reader.
-var decoder, _ = zstd.NewReader(nil)
+var decoder, _ = zstd.NewReader(nil, WithDecoderConcurrency(0))
 
 // Decompress a buffer. We don't supply a destination buffer,
 // so it will be allocated by the decoder.
@@ -303,9 +312,12 @@ func Decompress(src []byte) ([]byte, error) {
 ```
 
 Both of these cases should provide the functionality needed. 
-The decoder can be used for *concurrent* decompression of multiple buffers. 
+The decoder can be used for *concurrent* decompression of multiple buffers.
+By default 4 decompressors will be created. 
+
 It will only allow a certain number of concurrent operations to run. 
-To tweak that yourself use the `WithDecoderConcurrency(n)` option when creating the decoder.   
+To tweak that yourself use the `WithDecoderConcurrency(n)` option when creating the decoder.
+It is possible to use `WithDecoderConcurrency(0)` to create GOMAXPROCS decoders.
 
 ### Dictionaries
 
@@ -357,19 +369,21 @@ In this case no unneeded allocations should be made.
 The buffer decoder does everything on the same goroutine and does nothing concurrently.
 It can however decode several buffers concurrently. Use `WithDecoderConcurrency(n)` to limit that.
 
-The stream decoder operates on
+The stream decoder will create goroutines that:
 
-* One goroutine reads input and splits the input to several block decoders.
-* A number of decoders will decode blocks.
-* A goroutine coordinates these blocks and sends history from one to the next.
+1) Reads input and splits the input into blocks.
+2) Decompression of literals.
+3) Decompression of sequences.
+4) Reconstruction of output stream.
 
 So effectively this also means the decoder will "read ahead" and prepare data to always be available for output.
 
+The concurrency level will, for streams, determine how many blocks ahead the compression will start.
+
 Since "blocks" are quite dependent on the output of the previous block stream decoding will only have limited concurrency.
 
-In practice this means that concurrency is often limited to utilizing about 2 cores effectively.
- 
- 
+In practice this means that concurrency is often limited to utilizing about 3 cores effectively.
+  
 ### Benchmarks
 
 These are some examples of performance compared to [datadog cgo library](https://github.com/DataDog/zstd).
diff --git a/vendor/github.com/klauspost/compress/zstd/bitreader.go b/vendor/github.com/klauspost/compress/zstd/bitreader.go
index 753d17df..d7cd15ba 100644
--- a/vendor/github.com/klauspost/compress/zstd/bitreader.go
+++ b/vendor/github.com/klauspost/compress/zstd/bitreader.go
@@ -7,6 +7,7 @@ package zstd
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 	"math/bits"
 )
@@ -132,6 +133,9 @@ func (b *bitReader) remain() uint {
 func (b *bitReader) close() error {
 	// Release reference.
 	b.in = nil
+	if !b.finished() {
+		return fmt.Errorf("%d extra bits on block, should be 0", b.remain())
+	}
 	if b.bitsRead > 64 {
 		return io.ErrUnexpectedEOF
 	}
diff --git a/vendor/github.com/klauspost/compress/zstd/blockdec.go b/vendor/github.com/klauspost/compress/zstd/blockdec.go
index dc587b2c..7d567a54 100644
--- a/vendor/github.com/klauspost/compress/zstd/blockdec.go
+++ b/vendor/github.com/klauspost/compress/zstd/blockdec.go
@@ -76,16 +76,25 @@ type blockDec struct {
 	// Window size of the block.
 	WindowSize uint64
 
-	history chan *history
-	input   chan struct{}
-	result  chan decodeOutput
-	err     error
-	decWG   sync.WaitGroup
+	err error
+
+	// Check against this crc
+	checkCRC []byte
 
 	// Frame to use for singlethreaded decoding.
 	// Should not be used by the decoder itself since parent may be another frame.
 	localFrame *frameDec
 
+	sequence []seqVals
+
+	async struct {
+		newHist  *history
+		literals []byte
+		seqData  []byte
+		seqSize  int // Size of uncompressed sequences
+		fcs      uint64
+	}
+
 	// Block is RLE, this is the size.
 	RLESize uint32
 	tmp     [4]byte
@@ -108,13 +117,8 @@ func (b *blockDec) String() string {
 
 func newBlockDec(lowMem bool) *blockDec {
 	b := blockDec{
-		lowMem:  lowMem,
-		result:  make(chan decodeOutput, 1),
-		input:   make(chan struct{}, 1),
-		history: make(chan *history, 1),
+		lowMem: lowMem,
 	}
-	b.decWG.Add(1)
-	go b.startDecoder()
 	return &b
 }
 
@@ -137,6 +141,12 @@ func (b *blockDec) reset(br byteBuffer, windowSize uint64) error {
 	case blockTypeReserved:
 		return ErrReservedBlockType
 	case blockTypeRLE:
+		if cSize > maxCompressedBlockSize || cSize > int(b.WindowSize) {
+			if debugDecoder {
+				printf("rle block too big: csize:%d block: %+v\n", uint64(cSize), b)
+			}
+			return ErrWindowSizeExceeded
+		}
 		b.RLESize = uint32(cSize)
 		if b.lowMem {
 			maxSize = cSize
@@ -157,7 +167,19 @@ func (b *blockDec) reset(br byteBuffer, windowSize uint64) error {
 			}
 			return ErrCompressedSizeTooBig
 		}
+		// Empty compressed blocks must at least be 2 bytes
+		// for Literals_Block_Type and one for Sequences_Section_Header.
+		if cSize < 2 {
+			return ErrBlockTooSmall
+		}
 	case blockTypeRaw:
+		if cSize > maxCompressedBlockSize || cSize > int(b.WindowSize) {
+			if debugDecoder {
+				printf("rle block too big: csize:%d block: %+v\n", uint64(cSize), b)
+			}
+			return ErrWindowSizeExceeded
+		}
+
 		b.RLESize = 0
 		// We do not need a destination for raw blocks.
 		maxSize = -1
@@ -192,85 +214,14 @@ 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)
-	b.decWG.Wait()
-}
-
-// decodeAsync will prepare decoding the block when it receives input.
-// This will separate output and history.
-func (b *blockDec) startDecoder() {
-	defer b.decWG.Done()
-	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 debugDecoder {
-				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 debugDecoder {
-			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.
+// decodeBuf
 func (b *blockDec) decodeBuf(hist *history) error {
 	switch b.Type {
 	case blockTypeRLE:
@@ -293,14 +244,23 @@ func (b *blockDec) decodeBuf(hist *history) error {
 		return nil
 	case blockTypeCompressed:
 		saved := b.dst
-		b.dst = hist.b
-		hist.b = nil
+		// Append directly to history
+		if hist.ignoreBuffer == 0 {
+			b.dst = hist.b
+			hist.b = nil
+		} else {
+			b.dst = b.dst[:0]
+		}
 		err := b.decodeCompressed(hist)
 		if debugDecoder {
 			println("Decompressed to total", len(b.dst), "bytes, hash:", xxhash.Sum64(b.dst), "error:", err)
 		}
-		hist.b = b.dst
-		b.dst = saved
+		if hist.ignoreBuffer == 0 {
+			hist.b = b.dst
+			b.dst = saved
+		} else {
+			hist.appendKeep(b.dst)
+		}
 		return err
 	case blockTypeReserved:
 		// Used for returning errors.
@@ -310,30 +270,18 @@ func (b *blockDec) decodeBuf(hist *history) error {
 	}
 }
 
-// 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
-			}
-		}()
-	}
+func (b *blockDec) decodeLiterals(in []byte, hist *history) (remain []byte, err error) {
 	// There must be at least one byte for Literals_Block_Type and one for Sequences_Section_Header
 	if len(in) < 2 {
-		return ErrBlockTooSmall
+		return in, ErrBlockTooSmall
 	}
+
 	litType := literalsBlockType(in[0] & 3)
 	var litRegenSize int
 	var litCompSize int
 	sizeFormat := (in[0] >> 2) & 3
 	var fourStreams bool
+	var literals []byte
 	switch litType {
 	case literalsBlockRaw, literalsBlockRLE:
 		switch sizeFormat {
@@ -349,7 +297,7 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 			//  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
+				return in, ErrBlockTooSmall
 			}
 			litRegenSize = int(in[0]>>4) + (int(in[1]) << 4) + (int(in[2]) << 12)
 			in = in[3:]
@@ -360,7 +308,7 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 			// 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
+				return in, ErrBlockTooSmall
 			}
 			n := uint64(in[0]>>4) + (uint64(in[1]) << 4) + (uint64(in[2]) << 12)
 			litRegenSize = int(n & 1023)
@@ -371,7 +319,7 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 			fourStreams = true
 			if len(in) < 4 {
 				println("too small: litType:", litType, " sizeFormat", sizeFormat, len(in))
-				return ErrBlockTooSmall
+				return in, ErrBlockTooSmall
 			}
 			n := uint64(in[0]>>4) + (uint64(in[1]) << 4) + (uint64(in[2]) << 12) + (uint64(in[3]) << 20)
 			litRegenSize = int(n & 16383)
@@ -381,7 +329,7 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 			fourStreams = true
 			if len(in) < 5 {
 				println("too small: litType:", litType, " sizeFormat", sizeFormat, len(in))
-				return ErrBlockTooSmall
+				return in, 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)
@@ -392,13 +340,15 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 	if debugDecoder {
 		println("literals type:", litType, "litRegenSize:", litRegenSize, "litCompSize:", litCompSize, "sizeFormat:", sizeFormat, "4X:", fourStreams)
 	}
-	var literals []byte
-	var huff *huff0.Scratch
+	if litRegenSize > int(b.WindowSize) || litRegenSize > maxCompressedBlockSize {
+		return in, ErrWindowSizeExceeded
+	}
+
 	switch litType {
 	case literalsBlockRaw:
 		if len(in) < litRegenSize {
 			println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", litRegenSize)
-			return ErrBlockTooSmall
+			return in, ErrBlockTooSmall
 		}
 		literals = in[:litRegenSize]
 		in = in[litRegenSize:]
@@ -406,7 +356,7 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 	case literalsBlockRLE:
 		if len(in) < 1 {
 			println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", 1)
-			return ErrBlockTooSmall
+			return in, ErrBlockTooSmall
 		}
 		if cap(b.literalBuf) < litRegenSize {
 			if b.lowMem {
@@ -417,7 +367,6 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 					b.literalBuf = make([]byte, litRegenSize)
 				} else {
 					b.literalBuf = make([]byte, litRegenSize, maxCompressedLiteralSize)
-
 				}
 			}
 		}
@@ -433,7 +382,7 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 	case literalsBlockTreeless:
 		if len(in) < litCompSize {
 			println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", litCompSize)
-			return ErrBlockTooSmall
+			return in, ErrBlockTooSmall
 		}
 		// Store compressed literals, so we defer decoding until we get history.
 		literals = in[:litCompSize]
@@ -441,31 +390,65 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 		if debugDecoder {
 			printf("Found %d compressed literals\n", litCompSize)
 		}
+		huff := hist.huffTree
+		if huff == nil {
+			return in, 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.MaxDecodedSize = maxCompressedBlockSize
+		if fourStreams {
+			literals, err = huff.Decoder().Decompress4X(b.literalBuf[:0:litRegenSize], literals)
+		} else {
+			literals, err = huff.Decoder().Decompress1X(b.literalBuf[:0:litRegenSize], literals)
+		}
+		// Make sure we don't leak our literals buffer
+		if err != nil {
+			println("decompressing literals:", err)
+			return in, err
+		}
+		if len(literals) != litRegenSize {
+			return in, fmt.Errorf("literal output size mismatch want %d, got %d", litRegenSize, len(literals))
+		}
+
 	case literalsBlockCompressed:
 		if len(in) < litCompSize {
 			println("too small: litType:", litType, " sizeFormat", sizeFormat, "remain:", len(in), "want:", litCompSize)
-			return ErrBlockTooSmall
+			return in, 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)
+				b.literalBuf = make([]byte, 0, maxCompressedBlockSize)
 			}
 		}
-		if huff == nil {
-			huff = &huff0.Scratch{}
+		huff := hist.huffTree
+		if huff == nil || (hist.dict != nil && huff == hist.dict.litEnc) {
+			huff = huffDecoderPool.Get().(*huff0.Scratch)
+			if huff == nil {
+				huff = &huff0.Scratch{}
+			}
 		}
+		var err error
 		huff, literals, err = huff0.ReadTable(literals, huff)
 		if err != nil {
 			println("reading huffman table:", err)
-			return err
+			return in, err
 		}
+		hist.huffTree = huff
+		huff.MaxDecodedSize = maxCompressedBlockSize
 		// Use our out buffer.
 		if fourStreams {
 			literals, err = huff.Decoder().Decompress4X(b.literalBuf[:0:litRegenSize], literals)
@@ -474,27 +457,56 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 		}
 		if err != nil {
 			println("decoding compressed literals:", err)
-			return err
+			return in, err
 		}
 		// Make sure we don't leak our literals buffer
 		if len(literals) != litRegenSize {
-			return fmt.Errorf("literal output size mismatch want %d, got %d", litRegenSize, len(literals))
+			return in, fmt.Errorf("literal output size mismatch want %d, got %d", litRegenSize, len(literals))
 		}
 		if debugDecoder {
 			printf("Decompressed %d literals into %d bytes\n", litCompSize, litRegenSize)
 		}
 	}
+	hist.decoders.literals = literals
+	return in, nil
+}
+
+// decodeCompressed will start decompressing a block.
+func (b *blockDec) decodeCompressed(hist *history) error {
+	in := b.data
+	in, err := b.decodeLiterals(in, hist)
+	if err != nil {
+		return err
+	}
+	err = b.prepareSequences(in, hist)
+	if err != nil {
+		return err
+	}
+	if hist.decoders.nSeqs == 0 {
+		b.dst = append(b.dst, hist.decoders.literals...)
+		return nil
+	}
+	err = hist.decoders.decodeSync(hist)
+	if err != nil {
+		return err
+	}
+	b.dst = hist.decoders.out
+	hist.recentOffsets = hist.decoders.prevOffset
+	return nil
+}
 
+func (b *blockDec) prepareSequences(in []byte, hist *history) (err error) {
+	if debugDecoder {
+		printf("prepareSequences: %d byte(s) input\n", len(in))
+	}
 	// Decode Sequences
 	// https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#sequences-section
 	if len(in) < 1 {
 		return ErrBlockTooSmall
 	}
+	var nSeqs int
 	seqHeader := in[0]
-	nSeqs := 0
 	switch {
-	case seqHeader == 0:
-		in = in[1:]
 	case seqHeader < 128:
 		nSeqs = int(seqHeader)
 		in = in[1:]
@@ -511,8 +523,16 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 		nSeqs = 0x7f00 + int(in[1]) + (int(in[2]) << 8)
 		in = in[3:]
 	}
+	if nSeqs == 0 && len(in) != 0 {
+		// When no sequences, there should not be any more data...
+		if debugDecoder {
+			printf("prepareSequences: 0 sequences, but %d byte(s) left on stream\n", len(in))
+		}
+		return ErrUnexpectedBlockSize
+	}
 
-	var seqs = &sequenceDecs{}
+	var seqs = &hist.decoders
+	seqs.nSeqs = nSeqs
 	if nSeqs > 0 {
 		if len(in) < 1 {
 			return ErrBlockTooSmall
@@ -541,6 +561,9 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 			}
 			switch mode {
 			case compModePredefined:
+				if seq.fse != nil && !seq.fse.preDefined {
+					fseDecoderPool.Put(seq.fse)
+				}
 				seq.fse = &fsePredef[i]
 			case compModeRLE:
 				if br.remain() < 1 {
@@ -548,34 +571,36 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 				}
 				v := br.Uint8()
 				br.advance(1)
-				dec := fseDecoderPool.Get().(*fseDecoder)
+				if seq.fse == nil || seq.fse.preDefined {
+					seq.fse = 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
+				seq.fse.setRLE(symb)
 				if debugDecoder {
 					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 seq.fse == nil || seq.fse.preDefined {
+					seq.fse = fseDecoderPool.Get().(*fseDecoder)
+				}
+				err := seq.fse.readNCount(&br, uint16(maxTableSymbol[i]))
 				if err != nil {
 					println("Read table error:", err)
 					return err
 				}
-				err = dec.transform(symbolTableX[i])
+				err = seq.fse.transform(symbolTableX[i])
 				if err != nil {
 					println("Transform table error:", err)
 					return err
 				}
 				if debugDecoder {
-					println("Read table ok", "symbolLen:", dec.symbolLen)
+					println("Read table ok", "symbolLen:", seq.fse.symbolLen)
 				}
-				seq.fse = dec
 			case compModeRepeat:
 				seq.repeat = true
 			}
@@ -585,140 +610,89 @@ func (b *blockDec) decodeCompressed(hist *history) error {
 		}
 		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 literals 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
-		if fourStreams {
-			literals, err = huff.Decoder().Decompress4X(b.literalBuf[:0:litRegenSize], literals)
-		} else {
-			literals, err = huff.Decoder().Decompress1X(b.literalBuf[:0:litRegenSize], literals)
-		}
-		// Make sure we don't leak our literals buffer
-		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 {
-			if hist.dict == nil || hist.dict.litEnc != hist.huffTree {
-				huffDecoderPool.Put(hist.huffTree)
-			}
-			hist.huffTree = nil
-		}
-	}
-	if huff != nil {
-		hist.huffTree = huff
-	}
 	if debugDecoder {
-		println("Final literals:", len(literals), "hash:", xxhash.Sum64(literals), "and", nSeqs, "sequences.")
+		println("Literals:", len(seqs.literals), "hash:", xxhash.Sum64(seqs.literals), "and", seqs.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)
+		if len(b.sequence) > 0 {
+			b.sequence = b.sequence[:0]
 		}
 		return nil
 	}
-
-	seqs, err := seqs.mergeHistory(&hist.decoders)
-	if err != nil {
-		return err
-	}
-	if debugDecoder {
-		println("History merged ok")
+	br := seqs.br
+	if br == nil {
+		br = &bitReader{}
 	}
-	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, b.dst); err != nil {
+		println("initializing sequences:", err)
+		return err
+	}
+	return nil
+}
+
+func (b *blockDec) decodeSequences(hist *history) error {
+	if cap(b.sequence) < hist.decoders.nSeqs {
+		if b.lowMem {
+			b.sequence = make([]seqVals, 0, hist.decoders.nSeqs)
+		} else {
+			b.sequence = make([]seqVals, 0, 0x7F00+0xffff)
+		}
+	}
+	b.sequence = b.sequence[:hist.decoders.nSeqs]
+	if hist.decoders.nSeqs == 0 {
+		hist.decoders.seqSize = len(hist.decoders.literals)
+		return nil
+	}
+	hist.decoders.windowSize = hist.windowSize
+	hist.decoders.prevOffset = hist.recentOffsets
+	err := hist.decoders.decode(b.sequence)
+	hist.recentOffsets = hist.decoders.prevOffset
+	return err
+}
 
+func (b *blockDec) executeSequences(hist *history) error {
 	hbytes := hist.b
 	if len(hbytes) > hist.windowSize {
 		hbytes = hbytes[len(hbytes)-hist.windowSize:]
-		// We do not need history any more.
+		// We do not need history anymore.
 		if hist.dict != nil {
 			hist.dict.content = nil
 		}
 	}
-
-	if err := seqs.initialize(br, hist, literals, b.dst); err != nil {
-		println("initializing sequences:", err)
-		return err
-	}
-
-	err = seqs.decode(nSeqs, br, hbytes)
+	hist.decoders.windowSize = hist.windowSize
+	hist.decoders.out = b.dst[:0]
+	err := hist.decoders.execute(b.sequence, hbytes)
 	if err != nil {
 		return err
 	}
-	if !br.finished() {
-		return fmt.Errorf("%d extra bits on block, should be 0", br.remain())
-	}
+	return b.updateHistory(hist)
+}
 
-	err = br.close()
-	if err != nil {
-		printf("Closing sequences: %v, %+v\n", err, *br)
-	}
+func (b *blockDec) updateHistory(hist *history) error {
 	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
+	b.dst = hist.decoders.out
+	hist.recentOffsets = hist.decoders.prevOffset
 
-	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
+	} else {
+		hist.append(b.dst)
+		if debugDecoder {
+			println("Finished block with ", len(b.sequence), "sequences. Added", len(b.dst), "to history, now length", len(hist.b))
+		}
 	}
-	hist.append(b.dst)
-	hist.recentOffsets = seqs.prevOffset
-	if debugDecoder {
-		println("Finished block with literals:", len(literals), "and", nSeqs, "sequences.")
-	}
+	hist.decoders.out, hist.decoders.literals = nil, nil
 
 	return nil
 }
diff --git a/vendor/github.com/klauspost/compress/zstd/bytebuf.go b/vendor/github.com/klauspost/compress/zstd/bytebuf.go
index aab71c6c..b80191e4 100644
--- a/vendor/github.com/klauspost/compress/zstd/bytebuf.go
+++ b/vendor/github.com/klauspost/compress/zstd/bytebuf.go
@@ -113,6 +113,9 @@ func (r *readerWrapper) readBig(n int, dst []byte) ([]byte, error) {
 func (r *readerWrapper) readByte() (byte, error) {
 	n2, err := r.r.Read(r.tmp[:1])
 	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
 		return 0, err
 	}
 	if n2 != 1 {
diff --git a/vendor/github.com/klauspost/compress/zstd/decoder.go b/vendor/github.com/klauspost/compress/zstd/decoder.go
index f430f58b..9fcdaac1 100644
--- a/vendor/github.com/klauspost/compress/zstd/decoder.go
+++ b/vendor/github.com/klauspost/compress/zstd/decoder.go
@@ -5,9 +5,13 @@
 package zstd
 
 import (
-	"errors"
+	"bytes"
+	"context"
+	"encoding/binary"
 	"io"
 	"sync"
+
+	"github.com/klauspost/compress/zstd/internal/xxhash"
 )
 
 // Decoder provides decoding of zstandard streams.
@@ -22,12 +26,19 @@ type Decoder struct {
 	// Unreferenced decoders, ready for use.
 	decoders chan *blockDec
 
-	// Streams ready to be decoded.
-	stream chan decodeStream
-
 	// Current read position used for Reader functionality.
 	current decoderState
 
+	// sync stream decoding
+	syncStream struct {
+		decodedFrame uint64
+		br           readerWrapper
+		enabled      bool
+		inFrame      bool
+	}
+
+	frame *frameDec
+
 	// Custom dictionaries.
 	// Always uses copies.
 	dicts map[uint32]dict
@@ -46,7 +57,10 @@ type decoderState struct {
 	output chan decodeOutput
 
 	// cancel remaining output.
-	cancel chan struct{}
+	cancel context.CancelFunc
+
+	// crc of current frame
+	crc *xxhash.Digest
 
 	flushed bool
 }
@@ -81,7 +95,7 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 			return nil, err
 		}
 	}
-	d.current.output = make(chan decodeOutput, d.o.concurrent)
+	d.current.crc = xxhash.New()
 	d.current.flushed = true
 
 	if r == nil {
@@ -130,7 +144,7 @@ func (d *Decoder) Read(p []byte) (int, error) {
 				break
 			}
 			if !d.nextBlock(n == 0) {
-				return n, nil
+				return n, d.current.err
 			}
 		}
 	}
@@ -162,6 +176,7 @@ func (d *Decoder) Reset(r io.Reader) error {
 
 	d.drainOutput()
 
+	d.syncStream.br.r = nil
 	if r == nil {
 		d.current.err = ErrDecoderNilInput
 		if len(d.current.b) > 0 {
@@ -195,33 +210,39 @@ func (d *Decoder) Reset(r io.Reader) error {
 		}
 		return nil
 	}
-
-	if d.stream == nil {
-		d.stream = make(chan decodeStream, 1)
-		d.streamWg.Add(1)
-		go d.startStreamDecoder(d.stream)
-	}
-
 	// Remove current block.
+	d.stashDecoder()
 	d.current.decodeOutput = decodeOutput{}
 	d.current.err = nil
-	d.current.cancel = make(chan struct{})
 	d.current.flushed = false
 	d.current.d = nil
 
-	d.stream <- decodeStream{
-		r:      r,
-		output: d.current.output,
-		cancel: d.current.cancel,
+	// Ensure no-one else is still running...
+	d.streamWg.Wait()
+	if d.frame == nil {
+		d.frame = newFrameDec(d.o)
+	}
+
+	if d.o.concurrent == 1 {
+		return d.startSyncDecoder(r)
 	}
+
+	d.current.output = make(chan decodeOutput, d.o.concurrent)
+	ctx, cancel := context.WithCancel(context.Background())
+	d.current.cancel = cancel
+	d.streamWg.Add(1)
+	go d.startStreamDecoder(ctx, r, d.current.output)
+
 	return nil
 }
 
 // drainOutput will drain the output until errEndOfStream is sent.
 func (d *Decoder) drainOutput() {
 	if d.current.cancel != nil {
-		println("cancelling current")
-		close(d.current.cancel)
+		if debugDecoder {
+			println("cancelling current")
+		}
+		d.current.cancel()
 		d.current.cancel = nil
 	}
 	if d.current.d != nil {
@@ -243,12 +264,9 @@ func (d *Decoder) drainOutput() {
 			}
 			d.decoders <- v.d
 		}
-		if v.err == errEndOfStream {
-			println("current flushed")
-			d.current.flushed = true
-			return
-		}
 	}
+	d.current.output = nil
+	d.current.flushed = true
 }
 
 // WriteTo writes data to w until there's no more data to write or when an error occurs.
@@ -287,7 +305,7 @@ func (d *Decoder) WriteTo(w io.Writer) (int64, error) {
 // DecodeAll can be used concurrently.
 // The Decoder concurrency limits will be respected.
 func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
-	if d.current.err == ErrDecoderClosed {
+	if d.decoders == nil {
 		return dst, ErrDecoderClosed
 	}
 
@@ -300,6 +318,9 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 		}
 		frame.rawInput = nil
 		frame.bBuf = nil
+		if frame.history.decoders.br != nil {
+			frame.history.decoders.br.in = nil
+		}
 		d.decoders <- block
 	}()
 	frame.bBuf = input
@@ -307,27 +328,31 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 	for {
 		frame.history.reset()
 		err := frame.reset(&frame.bBuf)
-		if err == io.EOF {
-			if debugDecoder {
-				println("frame reset return EOF")
+		if err != nil {
+			if err == io.EOF {
+				if debugDecoder {
+					println("frame reset return EOF")
+				}
+				return dst, nil
 			}
-			return dst, nil
+			return dst, err
 		}
 		if frame.DictionaryID != nil {
 			dict, ok := d.dicts[*frame.DictionaryID]
 			if !ok {
 				return nil, ErrUnknownDictionary
 			}
+			if debugDecoder {
+				println("setting dict", frame.DictionaryID)
+			}
 			frame.history.setDict(&dict)
 		}
-		if err != nil {
-			return dst, err
-		}
-		if frame.FrameContentSize > d.o.maxDecodedSize-uint64(len(dst)) {
+
+		if frame.FrameContentSize != fcsUnknown && frame.FrameContentSize > d.o.maxDecodedSize-uint64(len(dst)) {
 			return dst, ErrDecoderSizeExceeded
 		}
-		if frame.FrameContentSize > 0 && frame.FrameContentSize < 1<<30 {
-			// Never preallocate moe than 1 GB up front.
+		if frame.FrameContentSize < 1<<30 {
+			// Never preallocate more than 1 GB up front.
 			if cap(dst)-len(dst) < int(frame.FrameContentSize) {
 				dst2 := make([]byte, len(dst), len(dst)+int(frame.FrameContentSize))
 				copy(dst2, dst)
@@ -368,33 +393,170 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 // If non-blocking mode is used the returned boolean will be false
 // if no data was available without blocking.
 func (d *Decoder) nextBlock(blocking bool) (ok bool) {
-	if d.current.d != nil {
-		if debugDecoder {
-			printf("re-adding current decoder %p", d.current.d)
-		}
-		d.decoders <- d.current.d
-		d.current.d = nil
-	}
 	if d.current.err != nil {
 		// Keep error state.
-		return blocking
+		return false
 	}
+	d.current.b = d.current.b[:0]
 
+	// SYNC:
+	if d.syncStream.enabled {
+		if !blocking {
+			return false
+		}
+		ok = d.nextBlockSync()
+		if !ok {
+			d.stashDecoder()
+		}
+		return ok
+	}
+
+	//ASYNC:
+	d.stashDecoder()
 	if blocking {
-		d.current.decodeOutput = <-d.current.output
+		d.current.decodeOutput, ok = <-d.current.output
 	} else {
 		select {
-		case d.current.decodeOutput = <-d.current.output:
+		case d.current.decodeOutput, ok = <-d.current.output:
 		default:
 			return false
 		}
 	}
+	if !ok {
+		// This should not happen, so signal error state...
+		d.current.err = io.ErrUnexpectedEOF
+		return false
+	}
+	next := d.current.decodeOutput
+	if next.d != nil && next.d.async.newHist != nil {
+		d.current.crc.Reset()
+	}
 	if debugDecoder {
-		println("got", len(d.current.b), "bytes, error:", d.current.err)
+		var tmp [4]byte
+		binary.LittleEndian.PutUint32(tmp[:], uint32(xxhash.Sum64(next.b)))
+		println("got", len(d.current.b), "bytes, error:", d.current.err, "data crc:", tmp)
+	}
+
+	if len(next.b) > 0 {
+		n, err := d.current.crc.Write(next.b)
+		if err == nil {
+			if n != len(next.b) {
+				d.current.err = io.ErrShortWrite
+			}
+		}
+	}
+	if next.err == nil && next.d != nil && len(next.d.checkCRC) != 0 {
+		got := d.current.crc.Sum64()
+		var tmp [4]byte
+		binary.LittleEndian.PutUint32(tmp[:], uint32(got))
+		if !bytes.Equal(tmp[:], next.d.checkCRC) && !ignoreCRC {
+			if debugDecoder {
+				println("CRC Check Failed:", tmp[:], " (got) !=", next.d.checkCRC, "(on stream)")
+			}
+			d.current.err = ErrCRCMismatch
+		} else {
+			if debugDecoder {
+				println("CRC ok", tmp[:])
+			}
+		}
+	}
+
+	return true
+}
+
+func (d *Decoder) nextBlockSync() (ok bool) {
+	if d.current.d == nil {
+		d.current.d = <-d.decoders
+	}
+	for len(d.current.b) == 0 {
+		if !d.syncStream.inFrame {
+			d.frame.history.reset()
+			d.current.err = d.frame.reset(&d.syncStream.br)
+			if d.current.err != nil {
+				return false
+			}
+			if d.frame.DictionaryID != nil {
+				dict, ok := d.dicts[*d.frame.DictionaryID]
+				if !ok {
+					d.current.err = ErrUnknownDictionary
+					return false
+				} else {
+					d.frame.history.setDict(&dict)
+				}
+			}
+			if d.frame.WindowSize > d.o.maxDecodedSize || d.frame.WindowSize > d.o.maxWindowSize {
+				d.current.err = ErrDecoderSizeExceeded
+				return false
+			}
+
+			d.syncStream.decodedFrame = 0
+			d.syncStream.inFrame = true
+		}
+		d.current.err = d.frame.next(d.current.d)
+		if d.current.err != nil {
+			return false
+		}
+		d.frame.history.ensureBlock()
+		if debugDecoder {
+			println("History trimmed:", len(d.frame.history.b), "decoded already:", d.syncStream.decodedFrame)
+		}
+		histBefore := len(d.frame.history.b)
+		d.current.err = d.current.d.decodeBuf(&d.frame.history)
+
+		if d.current.err != nil {
+			println("error after:", d.current.err)
+			return false
+		}
+		d.current.b = d.frame.history.b[histBefore:]
+		if debugDecoder {
+			println("history after:", len(d.frame.history.b))
+		}
+
+		// Check frame size (before CRC)
+		d.syncStream.decodedFrame += uint64(len(d.current.b))
+		if d.syncStream.decodedFrame > d.frame.FrameContentSize {
+			if debugDecoder {
+				printf("DecodedFrame (%d) > FrameContentSize (%d)\n", d.syncStream.decodedFrame, d.frame.FrameContentSize)
+			}
+			d.current.err = ErrFrameSizeExceeded
+			return false
+		}
+
+		// Check FCS
+		if d.current.d.Last && d.frame.FrameContentSize != fcsUnknown && d.syncStream.decodedFrame != d.frame.FrameContentSize {
+			if debugDecoder {
+				printf("DecodedFrame (%d) != FrameContentSize (%d)\n", d.syncStream.decodedFrame, d.frame.FrameContentSize)
+			}
+			d.current.err = ErrFrameSizeMismatch
+			return false
+		}
+
+		// Update/Check CRC
+		if d.frame.HasCheckSum {
+			d.frame.crc.Write(d.current.b)
+			if d.current.d.Last {
+				d.current.err = d.frame.checkCRC()
+				if d.current.err != nil {
+					println("CRC error:", d.current.err)
+					return false
+				}
+			}
+		}
+		d.syncStream.inFrame = !d.current.d.Last
 	}
 	return true
 }
 
+func (d *Decoder) stashDecoder() {
+	if d.current.d != nil {
+		if debugDecoder {
+			printf("re-adding current decoder %p", d.current.d)
+		}
+		d.decoders <- d.current.d
+		d.current.d = nil
+	}
+}
+
 // Close will release all resources.
 // It is NOT possible to reuse the decoder after this.
 func (d *Decoder) Close() {
@@ -402,10 +564,10 @@ func (d *Decoder) Close() {
 		return
 	}
 	d.drainOutput()
-	if d.stream != nil {
-		close(d.stream)
+	if d.current.cancel != nil {
+		d.current.cancel()
 		d.streamWg.Wait()
-		d.stream = nil
+		d.current.cancel = nil
 	}
 	if d.decoders != nil {
 		close(d.decoders)
@@ -456,100 +618,307 @@ type decodeOutput struct {
 	err error
 }
 
-type decodeStream struct {
-	r io.Reader
-
-	// Blocks ready to be written to output.
-	output chan decodeOutput
-
-	// cancel reading from the input
-	cancel chan struct{}
+func (d *Decoder) startSyncDecoder(r io.Reader) error {
+	d.frame.history.reset()
+	d.syncStream.br = readerWrapper{r: r}
+	d.syncStream.inFrame = false
+	d.syncStream.enabled = true
+	d.syncStream.decodedFrame = 0
+	return nil
 }
 
-// errEndOfStream indicates that everything from the stream was read.
-var errEndOfStream = errors.New("end-of-stream")
-
 // Create Decoder:
-// Spawn n block decoders. These accept tasks to decode a block.
-// Create goroutine that handles stream processing, this will send history to decoders as they are available.
-// Decoders update the history as they decode.
-// When a block is returned:
-// 		a) history is sent to the next decoder,
-// 		b) content written to CRC.
-// 		c) return data to WRITER.
-// 		d) wait for next block to return data.
-// Once WRITTEN, the decoders reused by the writer frame decoder for re-use.
-func (d *Decoder) startStreamDecoder(inStream chan decodeStream) {
+// ASYNC:
+// Spawn 4 go routines.
+// 0: Read frames and decode blocks.
+// 1: Decode block and literals. Receives hufftree and seqdecs, returns seqdecs and huff tree.
+// 2: Wait for recentOffsets if needed. Decode sequences, send recentOffsets.
+// 3: Wait for stream history, execute sequences, send stream history.
+func (d *Decoder) startStreamDecoder(ctx context.Context, r io.Reader, output chan decodeOutput) {
 	defer d.streamWg.Done()
-	frame := newFrameDec(d.o)
-	for stream := range inStream {
-		if debugDecoder {
-			println("got new stream")
+	br := readerWrapper{r: r}
+
+	var seqPrepare = make(chan *blockDec, d.o.concurrent)
+	var seqDecode = make(chan *blockDec, d.o.concurrent)
+	var seqExecute = make(chan *blockDec, d.o.concurrent)
+
+	// Async 1: Prepare blocks...
+	go func() {
+		var hist history
+		var hasErr bool
+		for block := range seqPrepare {
+			if hasErr {
+				if block != nil {
+					seqDecode <- block
+				}
+				continue
+			}
+			if block.async.newHist != nil {
+				if debugDecoder {
+					println("Async 1: new history")
+				}
+				hist.reset()
+				if block.async.newHist.dict != nil {
+					hist.setDict(block.async.newHist.dict)
+				}
+			}
+			if block.err != nil || block.Type != blockTypeCompressed {
+				hasErr = block.err != nil
+				seqDecode <- block
+				continue
+			}
+
+			remain, err := block.decodeLiterals(block.data, &hist)
+			block.err = err
+			hasErr = block.err != nil
+			if err == nil {
+				block.async.literals = hist.decoders.literals
+				block.async.seqData = remain
+			} else if debugDecoder {
+				println("decodeLiterals error:", err)
+			}
+			seqDecode <- block
 		}
-		br := readerWrapper{r: stream.r}
-	decodeStream:
-		for {
-			frame.history.reset()
-			err := frame.reset(&br)
-			if debugDecoder && err != nil {
-				println("Frame decoder returned", err)
+		close(seqDecode)
+	}()
+
+	// Async 2: Decode sequences...
+	go func() {
+		var hist history
+		var hasErr bool
+
+		for block := range seqDecode {
+			if hasErr {
+				if block != nil {
+					seqExecute <- block
+				}
+				continue
 			}
-			if err == nil && frame.DictionaryID != nil {
-				dict, ok := d.dicts[*frame.DictionaryID]
-				if !ok {
-					err = ErrUnknownDictionary
-				} else {
-					frame.history.setDict(&dict)
+			if block.async.newHist != nil {
+				if debugDecoder {
+					println("Async 2: new history, recent:", block.async.newHist.recentOffsets)
+				}
+				hist.decoders = block.async.newHist.decoders
+				hist.recentOffsets = block.async.newHist.recentOffsets
+				hist.windowSize = block.async.newHist.windowSize
+				if block.async.newHist.dict != nil {
+					hist.setDict(block.async.newHist.dict)
 				}
 			}
-			if err != nil {
-				stream.output <- decodeOutput{
-					err: err,
+			if block.err != nil || block.Type != blockTypeCompressed {
+				hasErr = block.err != nil
+				seqExecute <- block
+				continue
+			}
+
+			hist.decoders.literals = block.async.literals
+			block.err = block.prepareSequences(block.async.seqData, &hist)
+			if debugDecoder && block.err != nil {
+				println("prepareSequences returned:", block.err)
+			}
+			hasErr = block.err != nil
+			if block.err == nil {
+				block.err = block.decodeSequences(&hist)
+				if debugDecoder && block.err != nil {
+					println("decodeSequences returned:", block.err)
 				}
-				break
+				hasErr = block.err != nil
+				//				block.async.sequence = hist.decoders.seq[:hist.decoders.nSeqs]
+				block.async.seqSize = hist.decoders.seqSize
 			}
-			if debugDecoder {
-				println("starting frame decoder")
-			}
-
-			// This goroutine will forward history between frames.
-			frame.frameDone.Add(1)
-			frame.initAsync()
-
-			go frame.startDecoder(stream.output)
-		decodeFrame:
-			// Go through all blocks of the frame.
-			for {
-				dec := <-d.decoders
-				select {
-				case <-stream.cancel:
-					if !frame.sendErr(dec, io.EOF) {
-						// To not let the decoder dangle, send it back.
-						stream.output <- decodeOutput{d: dec}
+			seqExecute <- block
+		}
+		close(seqExecute)
+	}()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	// Async 3: Execute sequences...
+	frameHistCache := d.frame.history.b
+	go func() {
+		var hist history
+		var decodedFrame uint64
+		var fcs uint64
+		var hasErr bool
+		for block := range seqExecute {
+			out := decodeOutput{err: block.err, d: block}
+			if block.err != nil || hasErr {
+				hasErr = true
+				output <- out
+				continue
+			}
+			if block.async.newHist != nil {
+				if debugDecoder {
+					println("Async 3: new history")
+				}
+				hist.windowSize = block.async.newHist.windowSize
+				hist.allocFrameBuffer = block.async.newHist.allocFrameBuffer
+				if block.async.newHist.dict != nil {
+					hist.setDict(block.async.newHist.dict)
+				}
+
+				if cap(hist.b) < hist.allocFrameBuffer {
+					if cap(frameHistCache) >= hist.allocFrameBuffer {
+						hist.b = frameHistCache
+					} else {
+						hist.b = make([]byte, 0, hist.allocFrameBuffer)
+						println("Alloc history sized", hist.allocFrameBuffer)
+					}
+				}
+				hist.b = hist.b[:0]
+				fcs = block.async.fcs
+				decodedFrame = 0
+			}
+			do := decodeOutput{err: block.err, d: block}
+			switch block.Type {
+			case blockTypeRLE:
+				if debugDecoder {
+					println("add rle block length:", block.RLESize)
+				}
+
+				if cap(block.dst) < int(block.RLESize) {
+					if block.lowMem {
+						block.dst = make([]byte, block.RLESize)
+					} else {
+						block.dst = make([]byte, maxBlockSize)
 					}
-					break decodeStream
-				default:
 				}
-				err := frame.next(dec)
-				switch err {
-				case io.EOF:
-					// End of current frame, no error
-					println("EOF on next block")
-					break decodeFrame
-				case nil:
-					continue
-				default:
-					println("block decoder returned", err)
-					break decodeStream
+				block.dst = block.dst[:block.RLESize]
+				v := block.data[0]
+				for i := range block.dst {
+					block.dst[i] = v
+				}
+				hist.append(block.dst)
+				do.b = block.dst
+			case blockTypeRaw:
+				if debugDecoder {
+					println("add raw block length:", len(block.data))
+				}
+				hist.append(block.data)
+				do.b = block.data
+			case blockTypeCompressed:
+				if debugDecoder {
+					println("execute with history length:", len(hist.b), "window:", hist.windowSize)
+				}
+				hist.decoders.seqSize = block.async.seqSize
+				hist.decoders.literals = block.async.literals
+				do.err = block.executeSequences(&hist)
+				hasErr = do.err != nil
+				if debugDecoder && hasErr {
+					println("executeSequences returned:", do.err)
+				}
+				do.b = block.dst
+			}
+			if !hasErr {
+				decodedFrame += uint64(len(do.b))
+				if decodedFrame > fcs {
+					println("fcs exceeded", block.Last, fcs, decodedFrame)
+					do.err = ErrFrameSizeExceeded
+					hasErr = true
+				} else if block.Last && fcs != fcsUnknown && decodedFrame != fcs {
+					do.err = ErrFrameSizeMismatch
+					hasErr = true
+				} else {
+					if debugDecoder {
+						println("fcs ok", block.Last, fcs, decodedFrame)
+					}
 				}
 			}
-			// All blocks have started decoding, check if there are more frames.
-			println("waiting for done")
-			frame.frameDone.Wait()
-			println("done waiting...")
+			output <- do
+		}
+		close(output)
+		frameHistCache = hist.b
+		wg.Done()
+		if debugDecoder {
+			println("decoder goroutines finished")
+		}
+	}()
+
+decodeStream:
+	for {
+		frame := d.frame
+		if debugDecoder {
+			println("New frame...")
+		}
+		var historySent bool
+		frame.history.reset()
+		err := frame.reset(&br)
+		if debugDecoder && err != nil {
+			println("Frame decoder returned", err)
+		}
+		if err == nil && frame.DictionaryID != nil {
+			dict, ok := d.dicts[*frame.DictionaryID]
+			if !ok {
+				err = ErrUnknownDictionary
+			} else {
+				frame.history.setDict(&dict)
+			}
+		}
+		if err == nil && d.frame.WindowSize > d.o.maxWindowSize {
+			err = ErrDecoderSizeExceeded
+		}
+		if err != nil {
+			select {
+			case <-ctx.Done():
+			case dec := <-d.decoders:
+				dec.sendErr(err)
+				seqPrepare <- dec
+			}
+			break decodeStream
+		}
+
+		// Go through all blocks of the frame.
+		for {
+			var dec *blockDec
+			select {
+			case <-ctx.Done():
+				break decodeStream
+			case dec = <-d.decoders:
+				// Once we have a decoder, we MUST return it.
+			}
+			err := frame.next(dec)
+			if !historySent {
+				h := frame.history
+				if debugDecoder {
+					println("Alloc History:", h.allocFrameBuffer)
+				}
+				dec.async.newHist = &h
+				dec.async.fcs = frame.FrameContentSize
+				historySent = true
+			} else {
+				dec.async.newHist = nil
+			}
+			if debugDecoder && err != nil {
+				println("next block returned error:", err)
+			}
+			dec.err = err
+			dec.checkCRC = nil
+			if dec.Last && frame.HasCheckSum && err == nil {
+				crc, err := frame.rawInput.readSmall(4)
+				if err != nil {
+					println("CRC missing?", err)
+					dec.err = err
+				}
+				var tmp [4]byte
+				copy(tmp[:], crc)
+				dec.checkCRC = tmp[:]
+				if debugDecoder {
+					println("found crc to check:", dec.checkCRC)
+				}
+			}
+			err = dec.err
+			last := dec.Last
+			seqPrepare <- dec
+			if err != nil {
+				break decodeStream
+			}
+			if last {
+				break
+			}
 		}
-		frame.frameDone.Wait()
-		println("Sending EOS")
-		stream.output <- decodeOutput{err: errEndOfStream}
 	}
+	close(seqPrepare)
+	wg.Wait()
+	d.frame.history.b = frameHistCache
 }
diff --git a/vendor/github.com/klauspost/compress/zstd/decoder_options.go b/vendor/github.com/klauspost/compress/zstd/decoder_options.go
index 95cc9b8b..fd05c9bb 100644
--- a/vendor/github.com/klauspost/compress/zstd/decoder_options.go
+++ b/vendor/github.com/klauspost/compress/zstd/decoder_options.go
@@ -28,6 +28,9 @@ func (o *decoderOptions) setDefault() {
 		concurrent:    runtime.GOMAXPROCS(0),
 		maxWindowSize: MaxWindowSize,
 	}
+	if o.concurrent > 4 {
+		o.concurrent = 4
+	}
 	o.maxDecodedSize = 1 << 63
 }
 
@@ -37,16 +40,25 @@ func WithDecoderLowmem(b bool) DOption {
 	return func(o *decoderOptions) error { o.lowMem = b; return nil }
 }
 
-// WithDecoderConcurrency will set the concurrency,
-// meaning the maximum number of decoders to run concurrently.
-// The value supplied must be at least 1.
-// By default this will be set to GOMAXPROCS.
+// WithDecoderConcurrency sets the number of created decoders.
+// When decoding block with DecodeAll, this will limit the number
+// of possible concurrently running decodes.
+// When decoding streams, this will limit the number of
+// inflight blocks.
+// When decoding streams and setting maximum to 1,
+// no async decoding will be done.
+// When a value of 0 is provided GOMAXPROCS will be used.
+// By default this will be set to 4 or GOMAXPROCS, whatever is lower.
 func WithDecoderConcurrency(n int) DOption {
 	return func(o *decoderOptions) error {
-		if n <= 0 {
+		if n < 0 {
 			return errors.New("concurrency must be at least 1")
 		}
-		o.concurrent = n
+		if n == 0 {
+			o.concurrent = runtime.GOMAXPROCS(0)
+		} else {
+			o.concurrent = n
+		}
 		return nil
 	}
 }
diff --git a/vendor/github.com/klauspost/compress/zstd/enc_fast.go b/vendor/github.com/klauspost/compress/zstd/enc_fast.go
index 5f08a283..f51ab529 100644
--- a/vendor/github.com/klauspost/compress/zstd/enc_fast.go
+++ b/vendor/github.com/klauspost/compress/zstd/enc_fast.go
@@ -85,7 +85,7 @@ func (e *fastEncoder) Encode(blk *blockEnc, src []byte) {
 	// TEMPLATE
 	const hashLog = tableBits
 	// seems global, but would be nice to tweak.
-	const kSearchStrength = 7
+	const kSearchStrength = 6
 
 	// nextEmit is where in src the next emitLiteral should start from.
 	nextEmit := s
@@ -334,7 +334,7 @@ func (e *fastEncoder) EncodeNoHist(blk *blockEnc, src []byte) {
 	// TEMPLATE
 	const hashLog = tableBits
 	// seems global, but would be nice to tweak.
-	const kSearchStrength = 8
+	const kSearchStrength = 6
 
 	// nextEmit is where in src the next emitLiteral should start from.
 	nextEmit := s
diff --git a/vendor/github.com/klauspost/compress/zstd/encoder.go b/vendor/github.com/klauspost/compress/zstd/encoder.go
index e6e31596..dcc987a7 100644
--- a/vendor/github.com/klauspost/compress/zstd/encoder.go
+++ b/vendor/github.com/klauspost/compress/zstd/encoder.go
@@ -98,23 +98,25 @@ func (e *Encoder) Reset(w io.Writer) {
 	if cap(s.filling) == 0 {
 		s.filling = make([]byte, 0, e.o.blockSize)
 	}
-	if cap(s.current) == 0 {
-		s.current = make([]byte, 0, e.o.blockSize)
-	}
-	if cap(s.previous) == 0 {
-		s.previous = make([]byte, 0, e.o.blockSize)
+	if e.o.concurrent > 1 {
+		if cap(s.current) == 0 {
+			s.current = make([]byte, 0, e.o.blockSize)
+		}
+		if cap(s.previous) == 0 {
+			s.previous = make([]byte, 0, e.o.blockSize)
+		}
+		s.current = s.current[:0]
+		s.previous = s.previous[:0]
+		if s.writing == nil {
+			s.writing = &blockEnc{lowMem: e.o.lowMem}
+			s.writing.init()
+		}
+		s.writing.initNewEncode()
 	}
 	if s.encoder == nil {
 		s.encoder = e.o.encoder()
 	}
-	if s.writing == nil {
-		s.writing = &blockEnc{lowMem: e.o.lowMem}
-		s.writing.init()
-	}
-	s.writing.initNewEncode()
 	s.filling = s.filling[:0]
-	s.current = s.current[:0]
-	s.previous = s.previous[:0]
 	s.encoder.Reset(e.o.dict, false)
 	s.headerWritten = false
 	s.eofWritten = false
@@ -258,6 +260,46 @@ func (e *Encoder) nextBlock(final bool) error {
 		return s.err
 	}
 
+	// SYNC:
+	if e.o.concurrent == 1 {
+		src := s.filling
+		s.nInput += int64(len(s.filling))
+		if debugEncoder {
+			println("Adding sync block,", len(src), "bytes, final:", final)
+		}
+		enc := s.encoder
+		blk := enc.Block()
+		blk.reset(nil)
+		enc.Encode(blk, src)
+		blk.last = final
+		if final {
+			s.eofWritten = true
+		}
+
+		err := errIncompressible
+		// If we got the exact same number of literals as input,
+		// assume the literals cannot be compressed.
+		if len(src) != len(blk.literals) || len(src) != e.o.blockSize {
+			err = blk.encode(src, e.o.noEntropy, !e.o.allLitEntropy)
+		}
+		switch err {
+		case errIncompressible:
+			if debugEncoder {
+				println("Storing incompressible block as raw")
+			}
+			blk.encodeRaw(src)
+			// In fast mode, we do not transfer offsets, so we don't have to deal with changing the.
+		case nil:
+		default:
+			s.err = err
+			return err
+		}
+		_, s.err = s.w.Write(blk.output)
+		s.nWritten += int64(len(blk.output))
+		s.filling = s.filling[:0]
+		return s.err
+	}
+
 	// Move blocks forward.
 	s.filling, s.current, s.previous = s.previous[:0], s.filling, s.current
 	s.nInput += int64(len(s.current))
diff --git a/vendor/github.com/klauspost/compress/zstd/encoder_options.go b/vendor/github.com/klauspost/compress/zstd/encoder_options.go
index 5f2e1d02..44d8dbd1 100644
--- a/vendor/github.com/klauspost/compress/zstd/encoder_options.go
+++ b/vendor/github.com/klauspost/compress/zstd/encoder_options.go
@@ -76,6 +76,7 @@ func WithEncoderCRC(b bool) EOption {
 // WithEncoderConcurrency will set the concurrency,
 // meaning the maximum number of encoders to run concurrently.
 // The value supplied must be at least 1.
+// For streams, setting a value of 1 will disable async compression.
 // By default this will be set to GOMAXPROCS.
 func WithEncoderConcurrency(n int) EOption {
 	return func(o *encoderOptions) error {
diff --git a/vendor/github.com/klauspost/compress/zstd/framedec.go b/vendor/github.com/klauspost/compress/zstd/framedec.go
index 989c79f8..11089d22 100644
--- a/vendor/github.com/klauspost/compress/zstd/framedec.go
+++ b/vendor/github.com/klauspost/compress/zstd/framedec.go
@@ -8,23 +8,17 @@ import (
 	"bytes"
 	"encoding/hex"
 	"errors"
-	"hash"
 	"io"
-	"sync"
 
 	"github.com/klauspost/compress/zstd/internal/xxhash"
 )
 
 type frameDec struct {
-	o      decoderOptions
-	crc    hash.Hash64
-	offset int64
+	o   decoderOptions
+	crc *xxhash.Digest
 
 	WindowSize uint64
 
-	// In order queue of blocks being decoded.
-	decoding chan *blockDec
-
 	// Frame history passed between blocks
 	history history
 
@@ -34,15 +28,10 @@ type frameDec struct {
 	bBuf byteBuf
 
 	FrameContentSize uint64
-	frameDone        sync.WaitGroup
 
 	DictionaryID  *uint32
 	HasCheckSum   bool
 	SingleSegment bool
-
-	// asyncRunning indicates whether the async routine processes input on 'decoding'.
-	asyncRunningMu sync.Mutex
-	asyncRunning   bool
 }
 
 const (
@@ -208,7 +197,7 @@ func (d *frameDec) reset(br byteBuffer) error {
 	default:
 		fcsSize = 1 << v
 	}
-	d.FrameContentSize = 0
+	d.FrameContentSize = fcsUnknown
 	if fcsSize > 0 {
 		b, err := br.readSmall(fcsSize)
 		if err != nil {
@@ -229,9 +218,10 @@ func (d *frameDec) reset(br byteBuffer) error {
 			d.FrameContentSize = uint64(d1) | (uint64(d2) << 32)
 		}
 		if debugDecoder {
-			println("field size bits:", v, "fcsSize:", fcsSize, "FrameContentSize:", d.FrameContentSize, hex.EncodeToString(b[:fcsSize]), "singleseg:", d.SingleSegment, "window:", d.WindowSize)
+			println("Read FCS:", d.FrameContentSize)
 		}
 	}
+
 	// Move this to shared.
 	d.HasCheckSum = fhd&(1<<2) != 0
 	if d.HasCheckSum {
@@ -264,10 +254,16 @@ func (d *frameDec) reset(br byteBuffer) error {
 	}
 	d.history.windowSize = int(d.WindowSize)
 	if d.o.lowMem && d.history.windowSize < maxBlockSize {
-		d.history.maxSize = d.history.windowSize * 2
+		d.history.allocFrameBuffer = d.history.windowSize * 2
+		// TODO: Maybe use FrameContent size
 	} else {
-		d.history.maxSize = d.history.windowSize + maxBlockSize
+		d.history.allocFrameBuffer = d.history.windowSize + maxBlockSize
 	}
+
+	if debugDecoder {
+		println("Frame: Dict:", d.DictionaryID, "FrameContentSize:", d.FrameContentSize, "singleseg:", d.SingleSegment, "window:", d.WindowSize, "crc:", d.HasCheckSum)
+	}
+
 	// history contains input - maybe we do something
 	d.rawInput = br
 	return nil
@@ -276,49 +272,18 @@ func (d *frameDec) reset(br byteBuffer) error {
 // next will start decoding the next block from stream.
 func (d *frameDec) next(block *blockDec) error {
 	if debugDecoder {
-		printf("decoding new block %p:%p", block, block.data)
+		println("decoding new block")
 	}
 	err := block.reset(d.rawInput, d.WindowSize)
 	if err != nil {
 		println("block error:", err)
 		// Signal the frame decoder we have a problem.
-		d.sendErr(block, err)
+		block.sendErr(err)
 		return err
 	}
-	block.input <- struct{}{}
-	if debugDecoder {
-		println("next block:", block)
-	}
-	d.asyncRunningMu.Lock()
-	defer d.asyncRunningMu.Unlock()
-	if !d.asyncRunning {
-		return nil
-	}
-	if block.Last {
-		// We indicate the frame is done by sending io.EOF
-		d.decoding <- block
-		return io.EOF
-	}
-	d.decoding <- block
 	return nil
 }
 
-// sendEOF will queue an error block on the frame.
-// This will cause the frame decoder to return when it encounters the block.
-// Returns true if the decoder was added.
-func (d *frameDec) sendErr(block *blockDec, err error) bool {
-	d.asyncRunningMu.Lock()
-	defer d.asyncRunningMu.Unlock()
-	if !d.asyncRunning {
-		return false
-	}
-
-	println("sending error", err.Error())
-	block.sendErr(err)
-	d.decoding <- block
-	return true
-}
-
 // checkCRC will check the checksum if the frame has one.
 // Will return ErrCRCMismatch if crc check failed, otherwise nil.
 func (d *frameDec) checkCRC() error {
@@ -340,7 +305,7 @@ func (d *frameDec) checkCRC() error {
 		return err
 	}
 
-	if !bytes.Equal(tmp[:], want) {
+	if !bytes.Equal(tmp[:], want) && !ignoreCRC {
 		if debugDecoder {
 			println("CRC Check Failed:", tmp[:], "!=", want)
 		}
@@ -352,131 +317,13 @@ func (d *frameDec) checkCRC() error {
 	return nil
 }
 
-func (d *frameDec) initAsync() {
-	if !d.o.lowMem && !d.SingleSegment {
-		// set max extra size history to 2MB.
-		d.history.maxSize = d.history.windowSize + maxBlockSize
-	}
-	// re-alloc if more than one extra block size.
-	if d.o.lowMem && cap(d.history.b) > d.history.maxSize+maxBlockSize {
-		d.history.b = make([]byte, 0, d.history.maxSize)
-	}
-	if cap(d.history.b) < d.history.maxSize {
-		d.history.b = make([]byte, 0, d.history.maxSize)
-	}
-	if cap(d.decoding) < d.o.concurrent {
-		d.decoding = make(chan *blockDec, d.o.concurrent)
-	}
-	if debugDecoder {
-		h := d.history
-		printf("history init. len: %d, cap: %d", len(h.b), cap(h.b))
-	}
-	d.asyncRunningMu.Lock()
-	d.asyncRunning = true
-	d.asyncRunningMu.Unlock()
-}
-
-// startDecoder will start decoding blocks and write them to the writer.
-// The decoder will stop as soon as an error occurs or at end of frame.
-// When the frame has finished decoding the *bufio.Reader
-// containing the remaining input will be sent on frameDec.frameDone.
-func (d *frameDec) startDecoder(output chan decodeOutput) {
-	written := int64(0)
-
-	defer func() {
-		d.asyncRunningMu.Lock()
-		d.asyncRunning = false
-		d.asyncRunningMu.Unlock()
-
-		// Drain the currently decoding.
-		d.history.error = true
-	flushdone:
-		for {
-			select {
-			case b := <-d.decoding:
-				b.history <- &d.history
-				output <- <-b.result
-			default:
-				break flushdone
-			}
-		}
-		println("frame decoder done, signalling done")
-		d.frameDone.Done()
-	}()
-	// Get decoder for first block.
-	block := <-d.decoding
-	block.history <- &d.history
-	for {
-		var next *blockDec
-		// Get result
-		r := <-block.result
-		if r.err != nil {
-			println("Result contained error", r.err)
-			output <- r
-			return
-		}
-		if debugDecoder {
-			println("got result, from ", d.offset, "to", d.offset+int64(len(r.b)))
-			d.offset += int64(len(r.b))
-		}
-		if !block.Last {
-			// Send history to next block
-			select {
-			case next = <-d.decoding:
-				if debugDecoder {
-					println("Sending ", len(d.history.b), "bytes as history")
-				}
-				next.history <- &d.history
-			default:
-				// Wait until we have sent the block, so
-				// other decoders can potentially get the decoder.
-				next = nil
-			}
-		}
-
-		// Add checksum, async to decoding.
-		if d.HasCheckSum {
-			n, err := d.crc.Write(r.b)
-			if err != nil {
-				r.err = err
-				if n != len(r.b) {
-					r.err = io.ErrShortWrite
-				}
-				output <- r
-				return
-			}
-		}
-		written += int64(len(r.b))
-		if d.SingleSegment && uint64(written) > d.FrameContentSize {
-			println("runDecoder: single segment and", uint64(written), ">", d.FrameContentSize)
-			r.err = ErrFrameSizeExceeded
-			output <- r
-			return
-		}
-		if block.Last {
-			r.err = d.checkCRC()
-			output <- r
-			return
-		}
-		output <- r
-		if next == nil {
-			// There was no decoder available, we wait for one now that we have sent to the writer.
-			if debugDecoder {
-				println("Sending ", len(d.history.b), " bytes as history")
-			}
-			next = <-d.decoding
-			next.history <- &d.history
-		}
-		block = next
-	}
-}
-
 // runDecoder will create a sync decoder that will decode a block of data.
 func (d *frameDec) runDecoder(dst []byte, dec *blockDec) ([]byte, error) {
 	saved := d.history.b
 
 	// We use the history for output to avoid copying it.
 	d.history.b = dst
+	d.history.ignoreBuffer = len(dst)
 	// Store input length, so we only check new data.
 	crcStart := len(dst)
 	var err error
@@ -489,22 +336,30 @@ func (d *frameDec) runDecoder(dst []byte, dec *blockDec) ([]byte, error) {
 			println("next block:", dec)
 		}
 		err = dec.decodeBuf(&d.history)
-		if err != nil || dec.Last {
+		if err != nil {
 			break
 		}
 		if uint64(len(d.history.b)) > d.o.maxDecodedSize {
 			err = ErrDecoderSizeExceeded
 			break
 		}
-		if d.SingleSegment && uint64(len(d.history.b)) > d.o.maxDecodedSize {
-			println("runDecoder: single segment and", uint64(len(d.history.b)), ">", d.o.maxDecodedSize)
+		if uint64(len(d.history.b)-crcStart) > d.FrameContentSize {
+			println("runDecoder: FrameContentSize exceeded", uint64(len(d.history.b)-crcStart), ">", d.FrameContentSize)
 			err = ErrFrameSizeExceeded
 			break
 		}
+		if dec.Last {
+			break
+		}
+		if debugDecoder {
+			println("runDecoder: FrameContentSize", uint64(len(d.history.b)-crcStart), "<=", d.FrameContentSize)
+		}
 	}
 	dst = d.history.b
 	if err == nil {
-		if d.HasCheckSum {
+		if d.FrameContentSize != fcsUnknown && uint64(len(d.history.b)-crcStart) != d.FrameContentSize {
+			err = ErrFrameSizeMismatch
+		} else if d.HasCheckSum {
 			var n int
 			n, err = d.crc.Write(dst[crcStart:])
 			if err == nil {
diff --git a/vendor/github.com/klauspost/compress/zstd/fuzz.go b/vendor/github.com/klauspost/compress/zstd/fuzz.go
new file mode 100644
index 00000000..7f2210e0
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/fuzz.go
@@ -0,0 +1,11 @@
+//go:build ignorecrc
+// +build ignorecrc
+
+// 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
+
+// ignoreCRC can be used for fuzz testing to ignore CRC values...
+const ignoreCRC = true
diff --git a/vendor/github.com/klauspost/compress/zstd/fuzz_none.go b/vendor/github.com/klauspost/compress/zstd/fuzz_none.go
new file mode 100644
index 00000000..6811c68a
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/fuzz_none.go
@@ -0,0 +1,11 @@
+//go:build !ignorecrc
+// +build !ignorecrc
+
+// 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
+
+// ignoreCRC can be used for fuzz testing to ignore CRC values...
+const ignoreCRC = false
diff --git a/vendor/github.com/klauspost/compress/zstd/history.go b/vendor/github.com/klauspost/compress/zstd/history.go
index f783e32d..28b40153 100644
--- a/vendor/github.com/klauspost/compress/zstd/history.go
+++ b/vendor/github.com/klauspost/compress/zstd/history.go
@@ -10,20 +10,31 @@ import (
 
 // history contains the information transferred between blocks.
 type history struct {
-	b             []byte
-	huffTree      *huff0.Scratch
-	recentOffsets [3]int
+	// Literal decompression
+	huffTree *huff0.Scratch
+
+	// Sequence decompression
 	decoders      sequenceDecs
-	windowSize    int
-	maxSize       int
-	error         bool
-	dict          *dict
+	recentOffsets [3]int
+
+	// History buffer...
+	b []byte
+
+	// ignoreBuffer is meant to ignore a number of bytes
+	// when checking for matches in history
+	ignoreBuffer int
+
+	windowSize       int
+	allocFrameBuffer int // needed?
+	error            bool
+	dict             *dict
 }
 
 // reset will reset the history to initial state of a frame.
 // The history must already have been initialized to the desired size.
 func (h *history) reset() {
 	h.b = h.b[:0]
+	h.ignoreBuffer = 0
 	h.error = false
 	h.recentOffsets = [3]int{1, 4, 8}
 	if f := h.decoders.litLengths.fse; f != nil && !f.preDefined {
@@ -35,7 +46,7 @@ func (h *history) reset() {
 	if f := h.decoders.matchLengths.fse; f != nil && !f.preDefined {
 		fseDecoderPool.Put(f)
 	}
-	h.decoders = sequenceDecs{}
+	h.decoders = sequenceDecs{br: h.decoders.br}
 	if h.huffTree != nil {
 		if h.dict == nil || h.dict.litEnc != h.huffTree {
 			huffDecoderPool.Put(h.huffTree)
@@ -54,6 +65,7 @@ func (h *history) setDict(dict *dict) {
 	h.decoders.litLengths = dict.llDec
 	h.decoders.offsets = dict.ofDec
 	h.decoders.matchLengths = dict.mlDec
+	h.decoders.dict = dict.content
 	h.recentOffsets = dict.offsets
 	h.huffTree = dict.litEnc
 }
@@ -83,6 +95,24 @@ func (h *history) append(b []byte) {
 	copy(h.b[h.windowSize-len(b):], b)
 }
 
+// ensureBlock will ensure there is space for at least one block...
+func (h *history) ensureBlock() {
+	if cap(h.b) < h.allocFrameBuffer {
+		h.b = make([]byte, 0, h.allocFrameBuffer)
+		return
+	}
+
+	avail := cap(h.b) - len(h.b)
+	if avail >= h.windowSize || avail > maxCompressedBlockSize {
+		return
+	}
+	// Move data down so we only have window size left.
+	// We know we have less than window size in b at this point.
+	discard := len(h.b) - h.windowSize
+	copy(h.b, h.b[discard:])
+	h.b = h.b[:h.windowSize]
+}
+
 // append bytes to history without ever discarding anything.
 func (h *history) appendKeep(b []byte) {
 	h.b = append(h.b, b...)
diff --git a/vendor/github.com/klauspost/compress/zstd/seqdec.go b/vendor/github.com/klauspost/compress/zstd/seqdec.go
index bc731e4c..819f1461 100644
--- a/vendor/github.com/klauspost/compress/zstd/seqdec.go
+++ b/vendor/github.com/klauspost/compress/zstd/seqdec.go
@@ -20,6 +20,10 @@ type seq struct {
 	llCode, mlCode, ofCode uint8
 }
 
+type seqVals struct {
+	ll, ml, mo int
+}
+
 func (s seq) String() string {
 	if s.offset <= 3 {
 		if s.offset == 0 {
@@ -61,16 +65,18 @@ type sequenceDecs struct {
 	offsets      sequenceDec
 	matchLengths sequenceDec
 	prevOffset   [3]int
-	hist         []byte
 	dict         []byte
 	literals     []byte
 	out          []byte
+	nSeqs        int
+	br           *bitReader
+	seqSize      int
 	windowSize   int
 	maxBits      uint8
 }
 
 // initialize all 3 decoders from the stream input.
-func (s *sequenceDecs) initialize(br *bitReader, hist *history, literals, out []byte) error {
+func (s *sequenceDecs) initialize(br *bitReader, hist *history, out []byte) error {
 	if err := s.litLengths.init(br); err != nil {
 		return errors.New("litLengths:" + err.Error())
 	}
@@ -80,8 +86,7 @@ func (s *sequenceDecs) initialize(br *bitReader, hist *history, literals, out []
 	if err := s.matchLengths.init(br); err != nil {
 		return errors.New("matchLengths:" + err.Error())
 	}
-	s.literals = literals
-	s.hist = hist.b
+	s.br = br
 	s.prevOffset = hist.recentOffsets
 	s.maxBits = s.litLengths.fse.maxBits + s.offsets.fse.maxBits + s.matchLengths.fse.maxBits
 	s.windowSize = hist.windowSize
@@ -94,11 +99,261 @@ func (s *sequenceDecs) initialize(br *bitReader, hist *history, literals, out []
 }
 
 // decode sequences from the stream with the provided history.
-func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
+func (s *sequenceDecs) decode(seqs []seqVals) error {
+	br := s.br
+
+	// Grab full sizes tables, to avoid bounds checks.
+	llTable, mlTable, ofTable := s.litLengths.fse.dt[:maxTablesize], s.matchLengths.fse.dt[:maxTablesize], s.offsets.fse.dt[:maxTablesize]
+	llState, mlState, ofState := s.litLengths.state.state, s.matchLengths.state.state, s.offsets.state.state
+	s.seqSize = 0
+	litRemain := len(s.literals)
+	maxBlockSize := maxCompressedBlockSize
+	if s.windowSize < maxBlockSize {
+		maxBlockSize = s.windowSize
+	}
+	for i := range seqs {
+		var ll, mo, ml int
+		if br.off > 4+((maxOffsetBits+16+16)>>3) {
+			// inlined function:
+			// ll, mo, ml = s.nextFast(br, llState, mlState, ofState)
+
+			// Final will not read from stream.
+			var llB, mlB, moB uint8
+			ll, llB = llState.final()
+			ml, mlB = mlState.final()
+			mo, moB = ofState.final()
+
+			// extra bits are stored in reverse order.
+			br.fillFast()
+			mo += br.getBits(moB)
+			if s.maxBits > 32 {
+				br.fillFast()
+			}
+			ml += br.getBits(mlB)
+			ll += br.getBits(llB)
+
+			if moB > 1 {
+				s.prevOffset[2] = s.prevOffset[1]
+				s.prevOffset[1] = s.prevOffset[0]
+				s.prevOffset[0] = mo
+			} else {
+				// mo = s.adjustOffset(mo, ll, moB)
+				// Inlined for rather big speedup
+				if ll == 0 {
+					// There is an exception though, when current sequence's literals_length = 0.
+					// In this case, repeated offsets are shifted by one, so an offset_value of 1 means Repeated_Offset2,
+					// an offset_value of 2 means Repeated_Offset3, and an offset_value of 3 means Repeated_Offset1 - 1_byte.
+					mo++
+				}
+
+				if mo == 0 {
+					mo = s.prevOffset[0]
+				} else {
+					var temp int
+					if mo == 3 {
+						temp = s.prevOffset[0] - 1
+					} else {
+						temp = s.prevOffset[mo]
+					}
+
+					if temp == 0 {
+						// 0 is not valid; input is corrupted; force offset to 1
+						println("WARNING: temp was 0")
+						temp = 1
+					}
+
+					if mo != 1 {
+						s.prevOffset[2] = s.prevOffset[1]
+					}
+					s.prevOffset[1] = s.prevOffset[0]
+					s.prevOffset[0] = temp
+					mo = temp
+				}
+			}
+			br.fillFast()
+		} else {
+			if br.overread() {
+				if debugDecoder {
+					printf("reading sequence %d, exceeded available data\n", i)
+				}
+				return io.ErrUnexpectedEOF
+			}
+			ll, mo, ml = s.next(br, llState, mlState, ofState)
+			br.fill()
+		}
+
+		if debugSequences {
+			println("Seq", i, "Litlen:", ll, "mo:", mo, "(abs) ml:", ml)
+		}
+		// Evaluate.
+		// We might be doing this async, so do it early.
+		if mo == 0 && ml > 0 {
+			return fmt.Errorf("zero matchoff and matchlen (%d) > 0", ml)
+		}
+		if ml > maxMatchLen {
+			return fmt.Errorf("match len (%d) bigger than max allowed length", ml)
+		}
+		s.seqSize += ll + ml
+		if s.seqSize > maxBlockSize {
+			return fmt.Errorf("output (%d) bigger than max block size (%d)", s.seqSize, maxBlockSize)
+		}
+		litRemain -= ll
+		if litRemain < 0 {
+			return fmt.Errorf("unexpected literal count, want %d bytes, but only %d is available", ll, litRemain+ll)
+		}
+		seqs[i] = seqVals{
+			ll: ll,
+			ml: ml,
+			mo: mo,
+		}
+		if i == len(seqs)-1 {
+			// This is the last sequence, so we shouldn't update state.
+			break
+		}
+
+		// Manually inlined, ~ 5-20% faster
+		// Update all 3 states at once. Approx 20% faster.
+		nBits := llState.nbBits() + mlState.nbBits() + ofState.nbBits()
+		if nBits == 0 {
+			llState = llTable[llState.newState()&maxTableMask]
+			mlState = mlTable[mlState.newState()&maxTableMask]
+			ofState = ofTable[ofState.newState()&maxTableMask]
+		} else {
+			bits := br.get32BitsFast(nBits)
+			lowBits := uint16(bits >> ((ofState.nbBits() + mlState.nbBits()) & 31))
+			llState = llTable[(llState.newState()+lowBits)&maxTableMask]
+
+			lowBits = uint16(bits >> (ofState.nbBits() & 31))
+			lowBits &= bitMask[mlState.nbBits()&15]
+			mlState = mlTable[(mlState.newState()+lowBits)&maxTableMask]
+
+			lowBits = uint16(bits) & bitMask[ofState.nbBits()&15]
+			ofState = ofTable[(ofState.newState()+lowBits)&maxTableMask]
+		}
+	}
+	s.seqSize += litRemain
+	if s.seqSize > maxBlockSize {
+		return fmt.Errorf("output (%d) bigger than max block size (%d)", s.seqSize, maxBlockSize)
+	}
+	err := br.close()
+	if err != nil {
+		printf("Closing sequences: %v, %+v\n", err, *br)
+	}
+	return err
+}
+
+// execute will execute the decoded sequence with the provided history.
+// The sequence must be evaluated before being sent.
+func (s *sequenceDecs) execute(seqs []seqVals, hist []byte) error {
+	// Ensure we have enough output size...
+	if len(s.out)+s.seqSize > cap(s.out) {
+		addBytes := s.seqSize + len(s.out)
+		s.out = append(s.out, make([]byte, addBytes)...)
+		s.out = s.out[:len(s.out)-addBytes]
+	}
+
+	if debugDecoder {
+		printf("Execute %d seqs with hist %d, dict %d, literals: %d into %d bytes\n", len(seqs), len(hist), len(s.dict), len(s.literals), s.seqSize)
+	}
+
+	var t = len(s.out)
+	out := s.out[:t+s.seqSize]
+
+	for _, seq := range seqs {
+		// Add literals
+		copy(out[t:], s.literals[:seq.ll])
+		t += seq.ll
+		s.literals = s.literals[seq.ll:]
+
+		// Copy from dictionary...
+		if seq.mo > t+len(hist) || seq.mo > s.windowSize {
+			if len(s.dict) == 0 {
+				return fmt.Errorf("match offset (%d) bigger than current history (%d)", seq.mo, t+len(hist))
+			}
+
+			// we may be in dictionary.
+			dictO := len(s.dict) - (seq.mo - (t + len(hist)))
+			if dictO < 0 || dictO >= len(s.dict) {
+				return fmt.Errorf("match offset (%d) bigger than current history+dict (%d)", seq.mo, t+len(hist)+len(s.dict))
+			}
+			end := dictO + seq.ml
+			if end > len(s.dict) {
+				n := len(s.dict) - dictO
+				copy(out[t:], s.dict[dictO:])
+				t += n
+				seq.ml -= n
+			} else {
+				copy(out[t:], s.dict[dictO:end])
+				t += end - dictO
+				continue
+			}
+		}
+
+		// Copy from history.
+		if v := seq.mo - t; v > 0 {
+			// v is the start position in history from end.
+			start := len(hist) - v
+			if seq.ml > v {
+				// Some goes into current block.
+				// Copy remainder of history
+				copy(out[t:], hist[start:])
+				t += v
+				seq.ml -= v
+			} else {
+				copy(out[t:], hist[start:start+seq.ml])
+				t += seq.ml
+				continue
+			}
+		}
+		// We must be in current buffer now
+		if seq.ml > 0 {
+			start := t - seq.mo
+			if seq.ml <= t-start {
+				// No overlap
+				copy(out[t:], out[start:start+seq.ml])
+				t += seq.ml
+				continue
+			} else {
+				// Overlapping copy
+				// Extend destination slice and copy one byte at the time.
+				src := out[start : start+seq.ml]
+				dst := out[t:]
+				dst = dst[:len(src)]
+				t += len(src)
+				// Destination is the space we just added.
+				for i := range src {
+					dst[i] = src[i]
+				}
+			}
+		}
+	}
+	// Add final literals
+	copy(out[t:], s.literals)
+	if debugDecoder {
+		t += len(s.literals)
+		if t != len(out) {
+			panic(fmt.Errorf("length mismatch, want %d, got %d, ss: %d", len(out), t, s.seqSize))
+		}
+	}
+	s.out = out
+
+	return nil
+}
+
+// decode sequences from the stream with the provided history.
+func (s *sequenceDecs) decodeSync(history *history) error {
+	br := s.br
+	seqs := s.nSeqs
 	startSize := len(s.out)
 	// Grab full sizes tables, to avoid bounds checks.
 	llTable, mlTable, ofTable := s.litLengths.fse.dt[:maxTablesize], s.matchLengths.fse.dt[:maxTablesize], s.offsets.fse.dt[:maxTablesize]
 	llState, mlState, ofState := s.litLengths.state.state, s.matchLengths.state.state, s.offsets.state.state
+	hist := history.b[history.ignoreBuffer:]
+	out := s.out
+	maxBlockSize := maxCompressedBlockSize
+	if s.windowSize < maxBlockSize {
+		maxBlockSize = s.windowSize
+	}
 
 	for i := seqs - 1; i >= 0; i-- {
 		if br.overread() {
@@ -151,7 +406,7 @@ func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
 
 					if temp == 0 {
 						// 0 is not valid; input is corrupted; force offset to 1
-						println("temp was 0")
+						println("WARNING: temp was 0")
 						temp = 1
 					}
 
@@ -176,51 +431,49 @@ func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
 		if ll > len(s.literals) {
 			return fmt.Errorf("unexpected literal count, want %d bytes, but only %d is available", ll, len(s.literals))
 		}
-		size := ll + ml + len(s.out)
+		size := ll + ml + len(out)
 		if size-startSize > maxBlockSize {
-			return fmt.Errorf("output (%d) bigger than max block size", size)
+			return fmt.Errorf("output (%d) bigger than max block size (%d)", size, maxBlockSize)
 		}
-		if size > cap(s.out) {
+		if size > cap(out) {
 			// Not enough size, which can happen under high volume block streaming conditions
 			// but could be if destination slice is too small for sync operations.
 			// over-allocating here can create a large amount of GC pressure so we try to keep
 			// it as contained as possible
-			used := len(s.out) - startSize
+			used := len(out) - startSize
 			addBytes := 256 + ll + ml + used>>2
 			// Clamp to max block size.
 			if used+addBytes > maxBlockSize {
 				addBytes = maxBlockSize - used
 			}
-			s.out = append(s.out, make([]byte, addBytes)...)
-			s.out = s.out[:len(s.out)-addBytes]
+			out = append(out, make([]byte, addBytes)...)
+			out = out[:len(out)-addBytes]
 		}
 		if ml > maxMatchLen {
 			return fmt.Errorf("match len (%d) bigger than max allowed length", ml)
 		}
 
 		// Add literals
-		s.out = append(s.out, s.literals[:ll]...)
+		out = append(out, s.literals[:ll]...)
 		s.literals = s.literals[ll:]
-		out := s.out
 
 		if mo == 0 && ml > 0 {
 			return fmt.Errorf("zero matchoff and matchlen (%d) > 0", ml)
 		}
 
-		if mo > len(s.out)+len(hist) || mo > s.windowSize {
+		if mo > len(out)+len(hist) || mo > s.windowSize {
 			if len(s.dict) == 0 {
-				return fmt.Errorf("match offset (%d) bigger than current history (%d)", mo, len(s.out)+len(hist))
+				return fmt.Errorf("match offset (%d) bigger than current history (%d)", mo, len(out)+len(hist))
 			}
 
 			// we may be in dictionary.
-			dictO := len(s.dict) - (mo - (len(s.out) + len(hist)))
+			dictO := len(s.dict) - (mo - (len(out) + len(hist)))
 			if dictO < 0 || dictO >= len(s.dict) {
-				return fmt.Errorf("match offset (%d) bigger than current history (%d)", mo, len(s.out)+len(hist))
+				return fmt.Errorf("match offset (%d) bigger than current history (%d)", mo, len(out)+len(hist))
 			}
 			end := dictO + ml
 			if end > len(s.dict) {
 				out = append(out, s.dict[dictO:]...)
-				mo -= len(s.dict) - dictO
 				ml -= len(s.dict) - dictO
 			} else {
 				out = append(out, s.dict[dictO:end]...)
@@ -231,26 +484,25 @@ func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
 
 		// Copy from history.
 		// TODO: Blocks without history could be made to ignore this completely.
-		if v := mo - len(s.out); v > 0 {
+		if v := mo - len(out); v > 0 {
 			// v is the start position in history from end.
-			start := len(s.hist) - v
+			start := len(hist) - v
 			if ml > v {
 				// Some goes into current block.
 				// Copy remainder of history
-				out = append(out, s.hist[start:]...)
-				mo -= v
+				out = append(out, hist[start:]...)
 				ml -= v
 			} else {
-				out = append(out, s.hist[start:start+ml]...)
+				out = append(out, hist[start:start+ml]...)
 				ml = 0
 			}
 		}
 		// We must be in current buffer now
 		if ml > 0 {
-			start := len(s.out) - mo
-			if ml <= len(s.out)-start {
+			start := len(out) - mo
+			if ml <= len(out)-start {
 				// No overlap
-				out = append(out, s.out[start:start+ml]...)
+				out = append(out, out[start:start+ml]...)
 			} else {
 				// Overlapping copy
 				// Extend destination slice and copy one byte at the time.
@@ -264,7 +516,6 @@ func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
 				}
 			}
 		}
-		s.out = out
 		if i == 0 {
 			// This is the last sequence, so we shouldn't update state.
 			break
@@ -291,9 +542,14 @@ func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
 		}
 	}
 
+	// Check if space for literals
+	if len(s.literals)+len(s.out)-startSize > maxBlockSize {
+		return fmt.Errorf("output (%d) bigger than max block size (%d)", len(s.out), maxBlockSize)
+	}
+
 	// Add final literals
-	s.out = append(s.out, s.literals...)
-	return nil
+	s.out = append(out, s.literals...)
+	return br.close()
 }
 
 // update states, at least 27 bits must be available.
@@ -457,36 +713,3 @@ func (s *sequenceDecs) adjustOffset(offset, litLen int, offsetB uint8) int {
 	s.prevOffset[0] = temp
 	return temp
 }
-
-// mergeHistory will merge history.
-func (s *sequenceDecs) mergeHistory(hist *sequenceDecs) (*sequenceDecs, error) {
-	for i := uint(0); i < 3; i++ {
-		var sNew, sHist *sequenceDec
-		switch i {
-		default:
-			// same as "case 0":
-			sNew = &s.litLengths
-			sHist = &hist.litLengths
-		case 1:
-			sNew = &s.offsets
-			sHist = &hist.offsets
-		case 2:
-			sNew = &s.matchLengths
-			sHist = &hist.matchLengths
-		}
-		if sNew.repeat {
-			if sHist.fse == nil {
-				return nil, fmt.Errorf("sequence stream %d, repeat requested, but no history", i)
-			}
-			continue
-		}
-		if sNew.fse == nil {
-			return nil, fmt.Errorf("sequence stream %d, no fse found", i)
-		}
-		if sHist.fse != nil && !sHist.fse.preDefined {
-			fseDecoderPool.Put(sHist.fse)
-		}
-		sHist.fse = sNew.fse
-	}
-	return hist, nil
-}
diff --git a/vendor/github.com/klauspost/compress/zstd/zip.go b/vendor/github.com/klauspost/compress/zstd/zip.go
index 967f29b3..ffffcbc2 100644
--- a/vendor/github.com/klauspost/compress/zstd/zip.go
+++ b/vendor/github.com/klauspost/compress/zstd/zip.go
@@ -20,7 +20,7 @@ const ZipMethodPKWare = 20
 
 var zipReaderPool sync.Pool
 
-// newZipReader cannot be used since we would leak goroutines...
+// newZipReader creates a pooled zip decompressor.
 func newZipReader(r io.Reader) io.ReadCloser {
 	dec, ok := zipReaderPool.Get().(*Decoder)
 	if ok {
@@ -44,10 +44,14 @@ func (r *pooledZipReader) Read(p []byte) (n int, err error) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	if r.dec == nil {
-		return 0, errors.New("Read after Close")
+		return 0, errors.New("read after close or EOF")
 	}
 	dec, err := r.dec.Read(p)
-
+	if err == io.EOF {
+		err = r.dec.Reset(nil)
+		zipReaderPool.Put(r.dec)
+		r.dec = nil
+	}
 	return dec, err
 }
 
@@ -112,11 +116,5 @@ func ZipCompressor(opts ...EOption) func(w io.Writer) (io.WriteCloser, error) {
 // ZipDecompressor returns a decompressor that can be registered with zip libraries.
 // See ZipCompressor for example.
 func ZipDecompressor() func(r io.Reader) io.ReadCloser {
-	return func(r io.Reader) io.ReadCloser {
-		d, err := NewReader(r, WithDecoderConcurrency(1), WithDecoderLowmem(true))
-		if err != nil {
-			panic(err)
-		}
-		return d.IOReadCloser()
-	}
+	return newZipReader
 }
diff --git a/vendor/github.com/klauspost/compress/zstd/zstd.go b/vendor/github.com/klauspost/compress/zstd/zstd.go
index ef1d49a0..c1c90b4a 100644
--- a/vendor/github.com/klauspost/compress/zstd/zstd.go
+++ b/vendor/github.com/klauspost/compress/zstd/zstd.go
@@ -39,6 +39,9 @@ const zstdMinMatch = 3
 // Reset the buffer offset when reaching this.
 const bufferReset = math.MaxInt32 - MaxWindowSize
 
+// fcsUnknown is used for unknown frame content size.
+const fcsUnknown = math.MaxUint64
+
 var (
 	// ErrReservedBlockType is returned when a reserved block type is found.
 	// Typically this indicates wrong or corrupted input.
@@ -52,6 +55,10 @@ var (
 	// Typically returned on invalid input.
 	ErrBlockTooSmall = errors.New("block too small")
 
+	// ErrUnexpectedBlockSize is returned when a block has unexpected size.
+	// Typically returned on invalid input.
+	ErrUnexpectedBlockSize = errors.New("unexpected block size")
+
 	// ErrMagicMismatch is returned when a "magic" number isn't what is expected.
 	// Typically this indicates wrong or corrupted input.
 	ErrMagicMismatch = errors.New("invalid input: magic number mismatch")
@@ -75,6 +82,10 @@ var (
 	// This is only returned if SingleSegment is specified on the frame.
 	ErrFrameSizeExceeded = errors.New("frame size exceeded")
 
+	// ErrFrameSizeMismatch is returned if the stated frame size does not match the expected size.
+	// This is only returned if SingleSegment is specified on the frame.
+	ErrFrameSizeMismatch = errors.New("frame size does not match size on stream")
+
 	// ErrCRCMismatch is returned if CRC mismatches.
 	ErrCRCMismatch = errors.New("CRC check failed")