diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/seqdec.go')
-rw-r--r-- | vendor/github.com/klauspost/compress/zstd/seqdec.go | 102 |
1 files changed, 6 insertions, 96 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/seqdec.go b/vendor/github.com/klauspost/compress/zstd/seqdec.go index e80139dd9..df0447203 100644 --- a/vendor/github.com/klauspost/compress/zstd/seqdec.go +++ b/vendor/github.com/klauspost/compress/zstd/seqdec.go @@ -188,6 +188,7 @@ func (s *sequenceDecs) execute(seqs []seqVals, hist []byte) error { } } } + // Add final literals copy(out[t:], s.literals) if debugDecoder { @@ -203,12 +204,11 @@ func (s *sequenceDecs) execute(seqs []seqVals, hist []byte) error { // decode sequences from the stream with the provided history. func (s *sequenceDecs) decodeSync(hist []byte) error { - if true { - supported, err := s.decodeSyncSimple(hist) - if supported { - return err - } + supported, err := s.decodeSyncSimple(hist) + if supported { + return err } + br := s.br seqs := s.nSeqs startSize := len(s.out) @@ -396,6 +396,7 @@ func (s *sequenceDecs) decodeSync(hist []byte) error { ofState = ofTable[ofState.newState()&maxTableMask] } else { bits := br.get32BitsFast(nBits) + lowBits := uint16(bits >> ((ofState.nbBits() + mlState.nbBits()) & 31)) llState = llTable[(llState.newState()+lowBits)&maxTableMask] @@ -418,16 +419,6 @@ func (s *sequenceDecs) decodeSync(hist []byte) error { return br.close() } -// 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() { @@ -436,87 +427,6 @@ func init() { } } -// 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.get32BitsFast(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() |