mirror of
https://github.com/go-gitea/gitea.git
synced 2024-08-29 23:57:30 +02:00
* Add Dependencie Update Script * update gitea.com/lunny/levelqueue * update github.com/PuerkitoBio/goquery * update github.com/alecthomas/chroma * update github.com/blevesearch/bleve/v2 * update github.com/caddyserver/certmagic * update github.com/go-enry/go-enry/v2 * update github.com/go-redis/redis/v8 * update github.com/hashicorp/golang-lru * update github.com/klauspost/compress * update github.com/markbates/goth * update github.com/mholt/archiver/v3 * update github.com/microcosm-cc/bluemonday * update github.com/minio/minio-go/v7 * update github.com/olivere/elastic/v7 * update github.com/xanzy/go-gitlab * update github.com/yuin/goldmark
476 lines
12 KiB
Go
Vendored
476 lines
12 KiB
Go
Vendored
package lz4block
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"math/bits"
|
|
"sync"
|
|
|
|
"github.com/pierrec/lz4/v4/internal/lz4errors"
|
|
)
|
|
|
|
const (
|
|
// The following constants are used to setup the compression algorithm.
|
|
minMatch = 4 // the minimum size of the match sequence size (4 bytes)
|
|
winSizeLog = 16 // LZ4 64Kb window size limit
|
|
winSize = 1 << winSizeLog
|
|
winMask = winSize - 1 // 64Kb window of previous data for dependent blocks
|
|
|
|
// hashLog determines the size of the hash table used to quickly find a previous match position.
|
|
// Its value influences the compression speed and memory usage, the lower the faster,
|
|
// but at the expense of the compression ratio.
|
|
// 16 seems to be the best compromise for fast compression.
|
|
hashLog = 16
|
|
htSize = 1 << hashLog
|
|
|
|
mfLimit = 10 + minMatch // The last match cannot start within the last 14 bytes.
|
|
)
|
|
|
|
func recoverBlock(e *error) {
|
|
if r := recover(); r != nil && *e == nil {
|
|
*e = lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
}
|
|
|
|
// blockHash hashes the lower 6 bytes into a value < htSize.
|
|
func blockHash(x uint64) uint32 {
|
|
const prime6bytes = 227718039650203
|
|
return uint32(((x << (64 - 48)) * prime6bytes) >> (64 - hashLog))
|
|
}
|
|
|
|
func CompressBlockBound(n int) int {
|
|
return n + n/255 + 16
|
|
}
|
|
|
|
func UncompressBlock(src, dst, dict []byte) (int, error) {
|
|
if len(src) == 0 {
|
|
return 0, nil
|
|
}
|
|
if di := decodeBlock(dst, src, dict); di >= 0 {
|
|
return di, nil
|
|
}
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
|
|
type Compressor struct {
|
|
// Offsets are at most 64kiB, so we can store only the lower 16 bits of
|
|
// match positions: effectively, an offset from some 64kiB block boundary.
|
|
//
|
|
// When we retrieve such an offset, we interpret it as relative to the last
|
|
// block boundary si &^ 0xffff, or the one before, (si &^ 0xffff) - 0x10000,
|
|
// depending on which of these is inside the current window. If a table
|
|
// entry was generated more than 64kiB back in the input, we find out by
|
|
// inspecting the input stream.
|
|
table [htSize]uint16
|
|
|
|
needsReset bool
|
|
}
|
|
|
|
// Get returns the position of a presumptive match for the hash h.
|
|
// The match may be a false positive due to a hash collision or an old entry.
|
|
// If si < winSize, the return value may be negative.
|
|
func (c *Compressor) get(h uint32, si int) int {
|
|
h &= htSize - 1
|
|
i := int(c.table[h])
|
|
i += si &^ winMask
|
|
if i >= si {
|
|
// Try previous 64kiB block (negative when in first block).
|
|
i -= winSize
|
|
}
|
|
return i
|
|
}
|
|
|
|
func (c *Compressor) put(h uint32, si int) {
|
|
h &= htSize - 1
|
|
c.table[h] = uint16(si)
|
|
}
|
|
|
|
var compressorPool = sync.Pool{New: func() interface{} { return new(Compressor) }}
|
|
|
|
func CompressBlock(src, dst []byte) (int, error) {
|
|
c := compressorPool.Get().(*Compressor)
|
|
n, err := c.CompressBlock(src, dst)
|
|
compressorPool.Put(c)
|
|
return n, err
|
|
}
|
|
|
|
func (c *Compressor) CompressBlock(src, dst []byte) (int, error) {
|
|
if c.needsReset {
|
|
// Zero out reused table to avoid non-deterministic output (issue #65).
|
|
c.table = [htSize]uint16{}
|
|
}
|
|
c.needsReset = true // Only false on first call.
|
|
|
|
// Return 0, nil only if the destination buffer size is < CompressBlockBound.
|
|
isNotCompressible := len(dst) < CompressBlockBound(len(src))
|
|
|
|
// adaptSkipLog sets how quickly the compressor begins skipping blocks when data is incompressible.
|
|
// This significantly speeds up incompressible data and usually has very small impact on compression.
|
|
// bytes to skip = 1 + (bytes since last match >> adaptSkipLog)
|
|
const adaptSkipLog = 7
|
|
|
|
// si: Current position of the search.
|
|
// anchor: Position of the current literals.
|
|
var si, di, anchor int
|
|
sn := len(src) - mfLimit
|
|
if sn <= 0 {
|
|
goto lastLiterals
|
|
}
|
|
|
|
// Fast scan strategy: the hash table only stores the last 4 bytes sequences.
|
|
for si < sn {
|
|
// Hash the next 6 bytes (sequence)...
|
|
match := binary.LittleEndian.Uint64(src[si:])
|
|
h := blockHash(match)
|
|
h2 := blockHash(match >> 8)
|
|
|
|
// We check a match at s, s+1 and s+2 and pick the first one we get.
|
|
// Checking 3 only requires us to load the source one.
|
|
ref := c.get(h, si)
|
|
ref2 := c.get(h2, si)
|
|
c.put(h, si)
|
|
c.put(h2, si+1)
|
|
|
|
offset := si - ref
|
|
|
|
if offset <= 0 || offset >= winSize || uint32(match) != binary.LittleEndian.Uint32(src[ref:]) {
|
|
// No match. Start calculating another hash.
|
|
// The processor can usually do this out-of-order.
|
|
h = blockHash(match >> 16)
|
|
ref3 := c.get(h, si+2)
|
|
|
|
// Check the second match at si+1
|
|
si += 1
|
|
offset = si - ref2
|
|
|
|
if offset <= 0 || offset >= winSize || uint32(match>>8) != binary.LittleEndian.Uint32(src[ref2:]) {
|
|
// No match. Check the third match at si+2
|
|
si += 1
|
|
offset = si - ref3
|
|
c.put(h, si)
|
|
|
|
if offset <= 0 || offset >= winSize || uint32(match>>16) != binary.LittleEndian.Uint32(src[ref3:]) {
|
|
// Skip one extra byte (at si+3) before we check 3 matches again.
|
|
si += 2 + (si-anchor)>>adaptSkipLog
|
|
continue
|
|
}
|
|
}
|
|
}
|
|
|
|
// Match found.
|
|
lLen := si - anchor // Literal length.
|
|
// We already matched 4 bytes.
|
|
mLen := 4
|
|
|
|
// Extend backwards if we can, reducing literals.
|
|
tOff := si - offset - 1
|
|
for lLen > 0 && tOff >= 0 && src[si-1] == src[tOff] {
|
|
si--
|
|
tOff--
|
|
lLen--
|
|
mLen++
|
|
}
|
|
|
|
// Add the match length, so we continue search at the end.
|
|
// Use mLen to store the offset base.
|
|
si, mLen = si+mLen, si+minMatch
|
|
|
|
// Find the longest match by looking by batches of 8 bytes.
|
|
for si+8 < sn {
|
|
x := binary.LittleEndian.Uint64(src[si:]) ^ binary.LittleEndian.Uint64(src[si-offset:])
|
|
if x == 0 {
|
|
si += 8
|
|
} else {
|
|
// Stop is first non-zero byte.
|
|
si += bits.TrailingZeros64(x) >> 3
|
|
break
|
|
}
|
|
}
|
|
|
|
mLen = si - mLen
|
|
if di >= len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
if mLen < 0xF {
|
|
dst[di] = byte(mLen)
|
|
} else {
|
|
dst[di] = 0xF
|
|
}
|
|
|
|
// Encode literals length.
|
|
if lLen < 0xF {
|
|
dst[di] |= byte(lLen << 4)
|
|
} else {
|
|
dst[di] |= 0xF0
|
|
di++
|
|
l := lLen - 0xF
|
|
for ; l >= 0xFF && di < len(dst); l -= 0xFF {
|
|
dst[di] = 0xFF
|
|
di++
|
|
}
|
|
if di >= len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
dst[di] = byte(l)
|
|
}
|
|
di++
|
|
|
|
// Literals.
|
|
if di+lLen > len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
copy(dst[di:di+lLen], src[anchor:anchor+lLen])
|
|
di += lLen + 2
|
|
anchor = si
|
|
|
|
// Encode offset.
|
|
if di > len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
dst[di-2], dst[di-1] = byte(offset), byte(offset>>8)
|
|
|
|
// Encode match length part 2.
|
|
if mLen >= 0xF {
|
|
for mLen -= 0xF; mLen >= 0xFF && di < len(dst); mLen -= 0xFF {
|
|
dst[di] = 0xFF
|
|
di++
|
|
}
|
|
if di >= len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
dst[di] = byte(mLen)
|
|
di++
|
|
}
|
|
// Check if we can load next values.
|
|
if si >= sn {
|
|
break
|
|
}
|
|
// Hash match end-2
|
|
h = blockHash(binary.LittleEndian.Uint64(src[si-2:]))
|
|
c.put(h, si-2)
|
|
}
|
|
|
|
lastLiterals:
|
|
if isNotCompressible && anchor == 0 {
|
|
// Incompressible.
|
|
return 0, nil
|
|
}
|
|
|
|
// Last literals.
|
|
if di >= len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
lLen := len(src) - anchor
|
|
if lLen < 0xF {
|
|
dst[di] = byte(lLen << 4)
|
|
} else {
|
|
dst[di] = 0xF0
|
|
di++
|
|
for lLen -= 0xF; lLen >= 0xFF && di < len(dst); lLen -= 0xFF {
|
|
dst[di] = 0xFF
|
|
di++
|
|
}
|
|
if di >= len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
dst[di] = byte(lLen)
|
|
}
|
|
di++
|
|
|
|
// Write the last literals.
|
|
if isNotCompressible && di >= anchor {
|
|
// Incompressible.
|
|
return 0, nil
|
|
}
|
|
if di+len(src)-anchor > len(dst) {
|
|
return 0, lz4errors.ErrInvalidSourceShortBuffer
|
|
}
|
|
di += copy(dst[di:di+len(src)-anchor], src[anchor:])
|
|
return di, nil
|
|
}
|
|
|
|
// blockHash hashes 4 bytes into a value < winSize.
|
|
func blockHashHC(x uint32) uint32 {
|
|
const hasher uint32 = 2654435761 // Knuth multiplicative hash.
|
|
return x * hasher >> (32 - winSizeLog)
|
|
}
|
|
|
|
type CompressorHC struct {
|
|
// hashTable: stores the last position found for a given hash
|
|
// chainTable: stores previous positions for a given hash
|
|
hashTable, chainTable [htSize]int
|
|
needsReset bool
|
|
}
|
|
|
|
var compressorHCPool = sync.Pool{New: func() interface{} { return new(CompressorHC) }}
|
|
|
|
func CompressBlockHC(src, dst []byte, depth CompressionLevel) (int, error) {
|
|
c := compressorHCPool.Get().(*CompressorHC)
|
|
n, err := c.CompressBlock(src, dst, depth)
|
|
compressorHCPool.Put(c)
|
|
return n, err
|
|
}
|
|
|
|
func (c *CompressorHC) CompressBlock(src, dst []byte, depth CompressionLevel) (_ int, err error) {
|
|
if c.needsReset {
|
|
// Zero out reused table to avoid non-deterministic output (issue #65).
|
|
c.hashTable = [htSize]int{}
|
|
c.chainTable = [htSize]int{}
|
|
}
|
|
c.needsReset = true // Only false on first call.
|
|
|
|
defer recoverBlock(&err)
|
|
|
|
// Return 0, nil only if the destination buffer size is < CompressBlockBound.
|
|
isNotCompressible := len(dst) < CompressBlockBound(len(src))
|
|
|
|
// adaptSkipLog sets how quickly the compressor begins skipping blocks when data is incompressible.
|
|
// This significantly speeds up incompressible data and usually has very small impact on compression.
|
|
// bytes to skip = 1 + (bytes since last match >> adaptSkipLog)
|
|
const adaptSkipLog = 7
|
|
|
|
var si, di, anchor int
|
|
sn := len(src) - mfLimit
|
|
if sn <= 0 {
|
|
goto lastLiterals
|
|
}
|
|
|
|
if depth == 0 {
|
|
depth = winSize
|
|
}
|
|
|
|
for si < sn {
|
|
// Hash the next 4 bytes (sequence).
|
|
match := binary.LittleEndian.Uint32(src[si:])
|
|
h := blockHashHC(match)
|
|
|
|
// Follow the chain until out of window and give the longest match.
|
|
mLen := 0
|
|
offset := 0
|
|
for next, try := c.hashTable[h], depth; try > 0 && next > 0 && si-next < winSize; next, try = c.chainTable[next&winMask], try-1 {
|
|
// The first (mLen==0) or next byte (mLen>=minMatch) at current match length
|
|
// must match to improve on the match length.
|
|
if src[next+mLen] != src[si+mLen] {
|
|
continue
|
|
}
|
|
ml := 0
|
|
// Compare the current position with a previous with the same hash.
|
|
for ml < sn-si {
|
|
x := binary.LittleEndian.Uint64(src[next+ml:]) ^ binary.LittleEndian.Uint64(src[si+ml:])
|
|
if x == 0 {
|
|
ml += 8
|
|
} else {
|
|
// Stop is first non-zero byte.
|
|
ml += bits.TrailingZeros64(x) >> 3
|
|
break
|
|
}
|
|
}
|
|
if ml < minMatch || ml <= mLen {
|
|
// Match too small (<minMath) or smaller than the current match.
|
|
continue
|
|
}
|
|
// Found a longer match, keep its position and length.
|
|
mLen = ml
|
|
offset = si - next
|
|
// Try another previous position with the same hash.
|
|
}
|
|
c.chainTable[si&winMask] = c.hashTable[h]
|
|
c.hashTable[h] = si
|
|
|
|
// No match found.
|
|
if mLen == 0 {
|
|
si += 1 + (si-anchor)>>adaptSkipLog
|
|
continue
|
|
}
|
|
|
|
// Match found.
|
|
// Update hash/chain tables with overlapping bytes:
|
|
// si already hashed, add everything from si+1 up to the match length.
|
|
winStart := si + 1
|
|
if ws := si + mLen - winSize; ws > winStart {
|
|
winStart = ws
|
|
}
|
|
for si, ml := winStart, si+mLen; si < ml; {
|
|
match >>= 8
|
|
match |= uint32(src[si+3]) << 24
|
|
h := blockHashHC(match)
|
|
c.chainTable[si&winMask] = c.hashTable[h]
|
|
c.hashTable[h] = si
|
|
si++
|
|
}
|
|
|
|
lLen := si - anchor
|
|
si += mLen
|
|
mLen -= minMatch // Match length does not include minMatch.
|
|
|
|
if mLen < 0xF {
|
|
dst[di] = byte(mLen)
|
|
} else {
|
|
dst[di] = 0xF
|
|
}
|
|
|
|
// Encode literals length.
|
|
if lLen < 0xF {
|
|
dst[di] |= byte(lLen << 4)
|
|
} else {
|
|
dst[di] |= 0xF0
|
|
di++
|
|
l := lLen - 0xF
|
|
for ; l >= 0xFF; l -= 0xFF {
|
|
dst[di] = 0xFF
|
|
di++
|
|
}
|
|
dst[di] = byte(l)
|
|
}
|
|
di++
|
|
|
|
// Literals.
|
|
copy(dst[di:di+lLen], src[anchor:anchor+lLen])
|
|
di += lLen
|
|
anchor = si
|
|
|
|
// Encode offset.
|
|
di += 2
|
|
dst[di-2], dst[di-1] = byte(offset), byte(offset>>8)
|
|
|
|
// Encode match length part 2.
|
|
if mLen >= 0xF {
|
|
for mLen -= 0xF; mLen >= 0xFF; mLen -= 0xFF {
|
|
dst[di] = 0xFF
|
|
di++
|
|
}
|
|
dst[di] = byte(mLen)
|
|
di++
|
|
}
|
|
}
|
|
|
|
if isNotCompressible && anchor == 0 {
|
|
// Incompressible.
|
|
return 0, nil
|
|
}
|
|
|
|
// Last literals.
|
|
lastLiterals:
|
|
lLen := len(src) - anchor
|
|
if lLen < 0xF {
|
|
dst[di] = byte(lLen << 4)
|
|
} else {
|
|
dst[di] = 0xF0
|
|
di++
|
|
lLen -= 0xF
|
|
for ; lLen >= 0xFF; lLen -= 0xFF {
|
|
dst[di] = 0xFF
|
|
di++
|
|
}
|
|
dst[di] = byte(lLen)
|
|
}
|
|
di++
|
|
|
|
// Write the last literals.
|
|
if isNotCompressible && di >= anchor {
|
|
// Incompressible.
|
|
return 0, nil
|
|
}
|
|
di += copy(dst[di:di+len(src)-anchor], src[anchor:])
|
|
return di, nil
|
|
}
|