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author | 2024-08-19 10:13:46 +0000 | |
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committer | 2024-08-19 10:13:46 +0000 | |
commit | 6ff8376d96f094daacf62decf2ee7ff602c2d531 (patch) | |
tree | 0b0ad45951ef1aae841384fd550e01b44f4cba76 /vendor/github.com/klauspost/compress/zstd/seqdec.go | |
parent | [bugfix] permit unspecified orientation data (#3205) (diff) | |
download | gotosocial-6ff8376d96f094daacf62decf2ee7ff602c2d531.tar.xz |
[chore]: Bump github.com/prometheus/client_golang from 1.19.1 to 1.20.0 (#3210)
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/seqdec.go')
-rw-r--r-- | vendor/github.com/klauspost/compress/zstd/seqdec.go | 503 |
1 files changed, 503 insertions, 0 deletions
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 000000000..d7fe6d82d --- /dev/null +++ b/vendor/github.com/klauspost/compress/zstd/seqdec.go @@ -0,0 +1,503 @@ +// 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 +} + +type seqVals struct { + ll, ml, mo int +} + +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 + dict []byte + literals []byte + out []byte + nSeqs int + br *bitReader + seqSize int + windowSize int + maxBits uint8 + maxSyncLen uint64 +} + +// initialize all 3 decoders from the stream input. +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()) + } + 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.br = br + 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 +} + +func (s *sequenceDecs) freeDecoders() { + if f := s.litLengths.fse; f != nil && !f.preDefined { + fseDecoderPool.Put(f) + s.litLengths.fse = nil + } + if f := s.offsets.fse; f != nil && !f.preDefined { + fseDecoderPool.Put(f) + s.offsets.fse = nil + } + if f := s.matchLengths.fse; f != nil && !f.preDefined { + fseDecoderPool.Put(f) + s.matchLengths.fse = nil + } +} + +// 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 { + if len(s.dict) == 0 { + return s.executeSimple(seqs, hist) + } + + // 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(hist []byte) error { + supported, err := s.decodeSyncSimple(hist) + if supported { + return err + } + + 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 + out := s.out + maxBlockSize := maxCompressedBlockSize + if s.windowSize < maxBlockSize { + maxBlockSize = s.windowSize + } + + if debugDecoder { + println("decodeSync: decoding", seqs, "sequences", br.remain(), "bits remain on stream") + } + for i := seqs - 1; i >= 0; i-- { + if br.overread() { + printf("reading sequence %d, exceeded available data. Overread by %d\n", seqs-i, -br.remain()) + return io.ErrUnexpectedEOF + } + var ll, mo, ml int + if len(br.in) > 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 { + 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(out) + if size-startSize > maxBlockSize { + return fmt.Errorf("output bigger than max block size (%d)", maxBlockSize) + } + 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(out) - startSize + addBytes := 256 + ll + ml + used>>2 + // Clamp to max block size. + if used+addBytes > maxBlockSize { + addBytes = maxBlockSize - used + } + 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 + out = append(out, s.literals[:ll]...) + s.literals = s.literals[ll:] + + if mo == 0 && ml > 0 { + return fmt.Errorf("zero matchoff and matchlen (%d) > 0", ml) + } + + 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(out)+len(hist)-startSize) + } + + // we may be in dictionary. + 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(out)+len(hist)-startSize) + } + end := dictO + ml + if end > len(s.dict) { + out = append(out, 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(out); v > 0 { + // v is the start position in history from end. + start := len(hist) - v + if ml > v { + // Some goes into current block. + // Copy remainder of history + out = append(out, hist[start:]...) + ml -= v + } else { + out = append(out, hist[start:start+ml]...) + ml = 0 + } + } + // We must be in current buffer now + if ml > 0 { + start := len(out) - mo + if ml <= len(out)-start { + // No overlap + out = append(out, 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] + } + } + } + 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.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] + } + } + + if size := len(s.literals) + len(out) - startSize; size > maxBlockSize { + return fmt.Errorf("output bigger than max block size (%d)", maxBlockSize) + } + + // Add final literals + s.out = append(out, s.literals...) + return br.close() +} + +var bitMask [16]uint16 + +func init() { + for i := range bitMask[:] { + bitMask[i] = uint16((1 << uint(i)) - 1) + } +} + +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() + mo += br.getBits(moB) + if s.maxBits > 32 { + 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 +} |