[chore] migrate oauth2 -> codeberg (#3857)

vendor/github.com/klauspost/compress/s2/encode_all.go

@@ -10,14 +10,16 @@ import (
 	"encoding/binary"
 	"fmt"
 	"math/bits"
+
+	"github.com/klauspost/compress/internal/le"
 )
 
 func load32(b []byte, i int) uint32 {
-	return binary.LittleEndian.Uint32(b[i:])
+	return le.Load32(b, i)
 }
 
 func load64(b []byte, i int) uint64 {
-	return binary.LittleEndian.Uint64(b[i:])
+	return le.Load64(b, i)
 }
 
 // hash6 returns the hash of the lowest 6 bytes of u to fit in a hash table with h bits.
@@ -44,7 +46,12 @@ func encodeGo(dst, src []byte) []byte {
 		d += emitLiteral(dst[d:], src)
 		return dst[:d]
 	}
-	n := encodeBlockGo(dst[d:], src)
+	var n int
+	if len(src) < 64<<10 {
+		n = encodeBlockGo64K(dst[d:], src)
+	} else {
+		n = encodeBlockGo(dst[d:], src)
+	}
 	if n > 0 {
 		d += n
 		return dst[:d]
@@ -70,7 +77,6 @@ func encodeBlockGo(dst, src []byte) (d int) {
 
 		debug = false
 	)
-
 	var table [maxTableSize]uint32
 
 	// sLimit is when to stop looking for offset/length copies. The inputMargin
@@ -277,13 +283,228 @@ emitRemainder:
 	return d
 }
 
+// encodeBlockGo64K is a specialized version for compressing blocks <= 64KB
+func encodeBlockGo64K(dst, src []byte) (d int) {
+	// Initialize the hash table.
+	const (
+		tableBits    = 14
+		maxTableSize = 1 << tableBits
+
+		debug = false
+	)
+
+	var table [maxTableSize]uint16
+
+	// sLimit is when to stop looking for offset/length copies. The inputMargin
+	// lets us use a fast path for emitLiteral in the main loop, while we are
+	// looking for copies.
+	sLimit := len(src) - inputMargin
+
+	// Bail if we can't compress to at least this.
+	dstLimit := len(src) - len(src)>>5 - 5
+
+	// nextEmit is where in src the next emitLiteral should start from.
+	nextEmit := 0
+
+	// The encoded form must start with a literal, as there are no previous
+	// bytes to copy, so we start looking for hash matches at s == 1.
+	s := 1
+	cv := load64(src, s)
+
+	// We search for a repeat at -1, but don't output repeats when nextEmit == 0
+	repeat := 1
+
+	for {
+		candidate := 0
+		for {
+			// Next src position to check
+			nextS := s + (s-nextEmit)>>5 + 4
+			if nextS > sLimit {
+				goto emitRemainder
+			}
+			hash0 := hash6(cv, tableBits)
+			hash1 := hash6(cv>>8, tableBits)
+			candidate = int(table[hash0])
+			candidate2 := int(table[hash1])
+			table[hash0] = uint16(s)
+			table[hash1] = uint16(s + 1)
+			hash2 := hash6(cv>>16, tableBits)
+
+			// Check repeat at offset checkRep.
+			const checkRep = 1
+			if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
+				base := s + checkRep
+				// Extend back
+				for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
+					i--
+					base--
+				}
+
+				// Bail if we exceed the maximum size.
+				if d+(base-nextEmit) > dstLimit {
+					return 0
+				}
+
+				d += emitLiteral(dst[d:], src[nextEmit:base])
+
+				// Extend forward
+				candidate := s - repeat + 4 + checkRep
+				s += 4 + checkRep
+				for s <= sLimit {
+					if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
+						s += bits.TrailingZeros64(diff) >> 3
+						break
+					}
+					s += 8
+					candidate += 8
+				}
+				if debug {
+					// Validate match.
+					if s <= candidate {
+						panic("s <= candidate")
+					}
+					a := src[base:s]
+					b := src[base-repeat : base-repeat+(s-base)]
+					if !bytes.Equal(a, b) {
+						panic("mismatch")
+					}
+				}
+				if nextEmit > 0 {
+					// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
+					d += emitRepeat(dst[d:], repeat, s-base)
+				} else {
+					// First match, cannot be repeat.
+					d += emitCopy(dst[d:], repeat, s-base)
+				}
+				nextEmit = s
+				if s >= sLimit {
+					goto emitRemainder
+				}
+				cv = load64(src, s)
+				continue
+			}
+
+			if uint32(cv) == load32(src, candidate) {
+				break
+			}
+			candidate = int(table[hash2])
+			if uint32(cv>>8) == load32(src, candidate2) {
+				table[hash2] = uint16(s + 2)
+				candidate = candidate2
+				s++
+				break
+			}
+			table[hash2] = uint16(s + 2)
+			if uint32(cv>>16) == load32(src, candidate) {
+				s += 2
+				break
+			}
+
+			cv = load64(src, nextS)
+			s = nextS
+		}
+
+		// Extend backwards.
+		// The top bytes will be rechecked to get the full match.
+		for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
+			candidate--
+			s--
+		}
+
+		// Bail if we exceed the maximum size.
+		if d+(s-nextEmit) > dstLimit {
+			return 0
+		}
+
+		// A 4-byte match has been found. We'll later see if more than 4 bytes
+		// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
+		// them as literal bytes.
+
+		d += emitLiteral(dst[d:], src[nextEmit:s])
+
+		// Call emitCopy, and then see if another emitCopy could be our next
+		// move. Repeat until we find no match for the input immediately after
+		// what was consumed by the last emitCopy call.
+		//
+		// If we exit this loop normally then we need to call emitLiteral next,
+		// though we don't yet know how big the literal will be. We handle that
+		// by proceeding to the next iteration of the main loop. We also can
+		// exit this loop via goto if we get close to exhausting the input.
+		for {
+			// Invariant: we have a 4-byte match at s, and no need to emit any
+			// literal bytes prior to s.
+			base := s
+			repeat = base - candidate
+
+			// Extend the 4-byte match as long as possible.
+			s += 4
+			candidate += 4
+			for s <= len(src)-8 {
+				if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
+					s += bits.TrailingZeros64(diff) >> 3
+					break
+				}
+				s += 8
+				candidate += 8
+			}
+
+			d += emitCopy(dst[d:], repeat, s-base)
+			if debug {
+				// Validate match.
+				if s <= candidate {
+					panic("s <= candidate")
+				}
+				a := src[base:s]
+				b := src[base-repeat : base-repeat+(s-base)]
+				if !bytes.Equal(a, b) {
+					panic("mismatch")
+				}
+			}
+
+			nextEmit = s
+			if s >= sLimit {
+				goto emitRemainder
+			}
+
+			if d > dstLimit {
+				// Do we have space for more, if not bail.
+				return 0
+			}
+			// Check for an immediate match, otherwise start search at s+1
+			x := load64(src, s-2)
+			m2Hash := hash6(x, tableBits)
+			currHash := hash6(x>>16, tableBits)
+			candidate = int(table[currHash])
+			table[m2Hash] = uint16(s - 2)
+			table[currHash] = uint16(s)
+			if debug && s == candidate {
+				panic("s == candidate")
+			}
+			if uint32(x>>16) != load32(src, candidate) {
+				cv = load64(src, s+1)
+				s++
+				break
+			}
+		}
+	}
+
+emitRemainder:
+	if nextEmit < len(src) {
+		// Bail if we exceed the maximum size.
+		if d+len(src)-nextEmit > dstLimit {
+			return 0
+		}
+		d += emitLiteral(dst[d:], src[nextEmit:])
+	}
+	return d
+}
+
 func encodeBlockSnappyGo(dst, src []byte) (d int) {
 	// Initialize the hash table.
 	const (
 		tableBits    = 14
 		maxTableSize = 1 << tableBits
 	)
-
 	var table [maxTableSize]uint32
 
 	// sLimit is when to stop looking for offset/length copies. The inputMargin
@@ -467,6 +688,197 @@ emitRemainder:
 	return d
 }
 
+// encodeBlockSnappyGo64K is a special version of encodeBlockSnappyGo for sizes <64KB
+func encodeBlockSnappyGo64K(dst, src []byte) (d int) {
+	// Initialize the hash table.
+	const (
+		tableBits    = 14
+		maxTableSize = 1 << tableBits
+	)
+
+	var table [maxTableSize]uint16
+
+	// sLimit is when to stop looking for offset/length copies. The inputMargin
+	// lets us use a fast path for emitLiteral in the main loop, while we are
+	// looking for copies.
+	sLimit := len(src) - inputMargin
+
+	// Bail if we can't compress to at least this.
+	dstLimit := len(src) - len(src)>>5 - 5
+
+	// nextEmit is where in src the next emitLiteral should start from.
+	nextEmit := 0
+
+	// The encoded form must start with a literal, as there are no previous
+	// bytes to copy, so we start looking for hash matches at s == 1.
+	s := 1
+	cv := load64(src, s)
+
+	// We search for a repeat at -1, but don't output repeats when nextEmit == 0
+	repeat := 1
+
+	for {
+		candidate := 0
+		for {
+			// Next src position to check
+			nextS := s + (s-nextEmit)>>5 + 4
+			if nextS > sLimit {
+				goto emitRemainder
+			}
+			hash0 := hash6(cv, tableBits)
+			hash1 := hash6(cv>>8, tableBits)
+			candidate = int(table[hash0])
+			candidate2 := int(table[hash1])
+			table[hash0] = uint16(s)
+			table[hash1] = uint16(s + 1)
+			hash2 := hash6(cv>>16, tableBits)
+
+			// Check repeat at offset checkRep.
+			const checkRep = 1
+			if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
+				base := s + checkRep
+				// Extend back
+				for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
+					i--
+					base--
+				}
+				// Bail if we exceed the maximum size.
+				if d+(base-nextEmit) > dstLimit {
+					return 0
+				}
+
+				d += emitLiteral(dst[d:], src[nextEmit:base])
+
+				// Extend forward
+				candidate := s - repeat + 4 + checkRep
+				s += 4 + checkRep
+				for s <= sLimit {
+					if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
+						s += bits.TrailingZeros64(diff) >> 3
+						break
+					}
+					s += 8
+					candidate += 8
+				}
+
+				d += emitCopyNoRepeat(dst[d:], repeat, s-base)
+				nextEmit = s
+				if s >= sLimit {
+					goto emitRemainder
+				}
+
+				cv = load64(src, s)
+				continue
+			}
+
+			if uint32(cv) == load32(src, candidate) {
+				break
+			}
+			candidate = int(table[hash2])
+			if uint32(cv>>8) == load32(src, candidate2) {
+				table[hash2] = uint16(s + 2)
+				candidate = candidate2
+				s++
+				break
+			}
+			table[hash2] = uint16(s + 2)
+			if uint32(cv>>16) == load32(src, candidate) {
+				s += 2
+				break
+			}
+
+			cv = load64(src, nextS)
+			s = nextS
+		}
+
+		// Extend backwards
+		for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
+			candidate--
+			s--
+		}
+
+		// Bail if we exceed the maximum size.
+		if d+(s-nextEmit) > dstLimit {
+			return 0
+		}
+
+		// A 4-byte match has been found. We'll later see if more than 4 bytes
+		// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
+		// them as literal bytes.
+
+		d += emitLiteral(dst[d:], src[nextEmit:s])
+
+		// Call emitCopy, and then see if another emitCopy could be our next
+		// move. Repeat until we find no match for the input immediately after
+		// what was consumed by the last emitCopy call.
+		//
+		// If we exit this loop normally then we need to call emitLiteral next,
+		// though we don't yet know how big the literal will be. We handle that
+		// by proceeding to the next iteration of the main loop. We also can
+		// exit this loop via goto if we get close to exhausting the input.
+		for {
+			// Invariant: we have a 4-byte match at s, and no need to emit any
+			// literal bytes prior to s.
+			base := s
+			repeat = base - candidate
+
+			// Extend the 4-byte match as long as possible.
+			s += 4
+			candidate += 4
+			for s <= len(src)-8 {
+				if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
+					s += bits.TrailingZeros64(diff) >> 3
+					break
+				}
+				s += 8
+				candidate += 8
+			}
+
+			d += emitCopyNoRepeat(dst[d:], repeat, s-base)
+			if false {
+				// Validate match.
+				a := src[base:s]
+				b := src[base-repeat : base-repeat+(s-base)]
+				if !bytes.Equal(a, b) {
+					panic("mismatch")
+				}
+			}
+
+			nextEmit = s
+			if s >= sLimit {
+				goto emitRemainder
+			}
+
+			if d > dstLimit {
+				// Do we have space for more, if not bail.
+				return 0
+			}
+			// Check for an immediate match, otherwise start search at s+1
+			x := load64(src, s-2)
+			m2Hash := hash6(x, tableBits)
+			currHash := hash6(x>>16, tableBits)
+			candidate = int(table[currHash])
+			table[m2Hash] = uint16(s - 2)
+			table[currHash] = uint16(s)
+			if uint32(x>>16) != load32(src, candidate) {
+				cv = load64(src, s+1)
+				s++
+				break
+			}
+		}
+	}
+
+emitRemainder:
+	if nextEmit < len(src) {
+		// Bail if we exceed the maximum size.
+		if d+len(src)-nextEmit > dstLimit {
+			return 0
+		}
+		d += emitLiteral(dst[d:], src[nextEmit:])
+	}
+	return d
+}
+
 // encodeBlockGo encodes a non-empty src to a guaranteed-large-enough dst. It
 // assumes that the varint-encoded length of the decompressed bytes has already
 // been written.