diff --git a/vendor/github.com/klauspost/compress/zstd/seqdec.go b/vendor/github.com/klauspost/compress/zstd/seqdec.go
new file mode 100644
index 0000000..1dd39e6
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/seqdec.go
@@ -0,0 +1,492 @@
+// Copyright 2019+ Klaus Post. All rights reserved.
+// License information can be found in the LICENSE file.
+// Based on work by Yann Collet, released under BSD License.
+
+package zstd
+
+import (
+	"errors"
+	"fmt"
+	"io"
+)
+
+type seq struct {
+	litLen   uint32
+	matchLen uint32
+	offset   uint32
+
+	// Codes are stored here for the encoder
+	// so they only have to be looked up once.
+	llCode, mlCode, ofCode uint8
+}
+
+func (s seq) String() string {
+	if s.offset <= 3 {
+		if s.offset == 0 {
+			return fmt.Sprint("litLen:", s.litLen, ", matchLen:", s.matchLen+zstdMinMatch, ", offset: INVALID (0)")
+		}
+		return fmt.Sprint("litLen:", s.litLen, ", matchLen:", s.matchLen+zstdMinMatch, ", offset:", s.offset, " (repeat)")
+	}
+	return fmt.Sprint("litLen:", s.litLen, ", matchLen:", s.matchLen+zstdMinMatch, ", offset:", s.offset-3, " (new)")
+}
+
+type seqCompMode uint8
+
+const (
+	compModePredefined seqCompMode = iota
+	compModeRLE
+	compModeFSE
+	compModeRepeat
+)
+
+type sequenceDec struct {
+	// decoder keeps track of the current state and updates it from the bitstream.
+	fse    *fseDecoder
+	state  fseState
+	repeat bool
+}
+
+// init the state of the decoder with input from stream.
+func (s *sequenceDec) init(br *bitReader) error {
+	if s.fse == nil {
+		return errors.New("sequence decoder not defined")
+	}
+	s.state.init(br, s.fse.actualTableLog, s.fse.dt[:1<<s.fse.actualTableLog])
+	return nil
+}
+
+// sequenceDecs contains all 3 sequence decoders and their state.
+type sequenceDecs struct {
+	litLengths   sequenceDec
+	offsets      sequenceDec
+	matchLengths sequenceDec
+	prevOffset   [3]int
+	hist         []byte
+	dict         []byte
+	literals     []byte
+	out          []byte
+	windowSize   int
+	maxBits      uint8
+}
+
+// initialize all 3 decoders from the stream input.
+func (s *sequenceDecs) initialize(br *bitReader, hist *history, literals, out []byte) error {
+	if err := s.litLengths.init(br); err != nil {
+		return errors.New("litLengths:" + err.Error())
+	}
+	if err := s.offsets.init(br); err != nil {
+		return errors.New("offsets:" + err.Error())
+	}
+	if err := s.matchLengths.init(br); err != nil {
+		return errors.New("matchLengths:" + err.Error())
+	}
+	s.literals = literals
+	s.hist = hist.b
+	s.prevOffset = hist.recentOffsets
+	s.maxBits = s.litLengths.fse.maxBits + s.offsets.fse.maxBits + s.matchLengths.fse.maxBits
+	s.windowSize = hist.windowSize
+	s.out = out
+	s.dict = nil
+	if hist.dict != nil {
+		s.dict = hist.dict.content
+	}
+	return nil
+}
+
+// decode sequences from the stream with the provided history.
+func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
+	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
+
+	for i := seqs - 1; i >= 0; i-- {
+		if br.overread() {
+			printf("reading sequence %d, exceeded available data\n", seqs-i)
+			return io.ErrUnexpectedEOF
+		}
+		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("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 {
+			ll, mo, ml = s.next(br, llState, mlState, ofState)
+			br.fill()
+		}
+
+		if debugSequences {
+			println("Seq", seqs-i-1, "Litlen:", ll, "mo:", mo, "(abs) ml:", ml)
+		}
+
+		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)
+		if size-startSize > maxBlockSize {
+			return fmt.Errorf("output (%d) bigger than max block size", size)
+		}
+		if size > cap(s.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
+			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]
+		}
+		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]...)
+		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 len(s.dict) == 0 {
+				return fmt.Errorf("match offset (%d) bigger than current history (%d)", mo, len(s.out)+len(hist))
+			}
+
+			// we may be in dictionary.
+			dictO := len(s.dict) - (mo - (len(s.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))
+			}
+			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]...)
+				mo = 0
+				ml = 0
+			}
+		}
+
+		// Copy from history.
+		// TODO: Blocks without history could be made to ignore this completely.
+		if v := mo - len(s.out); v > 0 {
+			// v is the start position in history from end.
+			start := len(s.hist) - v
+			if ml > v {
+				// Some goes into current block.
+				// Copy remainder of history
+				out = append(out, s.hist[start:]...)
+				mo -= v
+				ml -= v
+			} else {
+				out = append(out, s.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 {
+				// No overlap
+				out = append(out, s.out[start:start+ml]...)
+			} else {
+				// Overlapping copy
+				// Extend destination slice and copy one byte at the time.
+				out = out[:len(out)+ml]
+				src := out[start : start+ml]
+				// Destination is the space we just added.
+				dst := out[len(out)-ml:]
+				dst = dst[:len(src)]
+				for i := range src {
+					dst[i] = src[i]
+				}
+			}
+		}
+		s.out = out
+		if i == 0 {
+			// 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.getBitsFast(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]
+		}
+	}
+
+	// Add final literals
+	s.out = append(s.out, s.literals...)
+	return nil
+}
+
+// update states, at least 27 bits must be available.
+func (s *sequenceDecs) update(br *bitReader) {
+	// Max 8 bits
+	s.litLengths.state.next(br)
+	// Max 9 bits
+	s.matchLengths.state.next(br)
+	// Max 8 bits
+	s.offsets.state.next(br)
+}
+
+var bitMask [16]uint16
+
+func init() {
+	for i := range bitMask[:] {
+		bitMask[i] = uint16((1 << uint(i)) - 1)
+	}
+}
+
+// update states, at least 27 bits must be available.
+func (s *sequenceDecs) updateAlt(br *bitReader) {
+	// Update all 3 states at once. Approx 20% faster.
+	a, b, c := s.litLengths.state.state, s.matchLengths.state.state, s.offsets.state.state
+
+	nBits := a.nbBits() + b.nbBits() + c.nbBits()
+	if nBits == 0 {
+		s.litLengths.state.state = s.litLengths.state.dt[a.newState()]
+		s.matchLengths.state.state = s.matchLengths.state.dt[b.newState()]
+		s.offsets.state.state = s.offsets.state.dt[c.newState()]
+		return
+	}
+	bits := br.getBitsFast(nBits)
+	lowBits := uint16(bits >> ((c.nbBits() + b.nbBits()) & 31))
+	s.litLengths.state.state = s.litLengths.state.dt[a.newState()+lowBits]
+
+	lowBits = uint16(bits >> (c.nbBits() & 31))
+	lowBits &= bitMask[b.nbBits()&15]
+	s.matchLengths.state.state = s.matchLengths.state.dt[b.newState()+lowBits]
+
+	lowBits = uint16(bits) & bitMask[c.nbBits()&15]
+	s.offsets.state.state = s.offsets.state.dt[c.newState()+lowBits]
+}
+
+// nextFast will return new states when there are at least 4 unused bytes left on the stream when done.
+func (s *sequenceDecs) nextFast(br *bitReader, llState, mlState, ofState decSymbol) (ll, mo, ml int) {
+	// Final will not read from stream.
+	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
+		return
+	}
+	// 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]
+		return
+	}
+	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("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
+	return
+}
+
+func (s *sequenceDecs) next(br *bitReader, llState, mlState, ofState decSymbol) (ll, mo, ml int) {
+	// Final will not read from stream.
+	ll, llB := llState.final()
+	ml, mlB := mlState.final()
+	mo, moB := ofState.final()
+
+	// extra bits are stored in reverse order.
+	br.fill()
+	if s.maxBits <= 32 {
+		mo += br.getBits(moB)
+		ml += br.getBits(mlB)
+		ll += br.getBits(llB)
+	} else {
+		mo += br.getBits(moB)
+		br.fill()
+		// matchlength+literal length, max 32 bits
+		ml += br.getBits(mlB)
+		ll += br.getBits(llB)
+
+	}
+	mo = s.adjustOffset(mo, ll, moB)
+	return
+}
+
+func (s *sequenceDecs) adjustOffset(offset, litLen int, offsetB uint8) int {
+	if offsetB > 1 {
+		s.prevOffset[2] = s.prevOffset[1]
+		s.prevOffset[1] = s.prevOffset[0]
+		s.prevOffset[0] = offset
+		return offset
+	}
+
+	if litLen == 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.
+		offset++
+	}
+
+	if offset == 0 {
+		return s.prevOffset[0]
+	}
+	var temp int
+	if offset == 3 {
+		temp = s.prevOffset[0] - 1
+	} else {
+		temp = s.prevOffset[offset]
+	}
+
+	if temp == 0 {
+		// 0 is not valid; input is corrupted; force offset to 1
+		println("temp was 0")
+		temp = 1
+	}
+
+	if offset != 1 {
+		s.prevOffset[2] = s.prevOffset[1]
+	}
+	s.prevOffset[1] = s.prevOffset[0]
+	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
+}