1 files changed, 298 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/s2/encode_go.go b/vendor/github.com/klauspost/compress/s2/encode_go.go
new file mode 100644
index 00000000..43d43534
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/s2/encode_go.go
@@ -0,0 +1,298 @@
+//go:build !amd64 || appengine || !gc || noasm
+// +build !amd64 appengine !gc noasm
+
+package s2
+
+import (
+	"math/bits"
+)
+
+// encodeBlock 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.
+//
+// It also assumes that:
+//	len(dst) >= MaxEncodedLen(len(src))
+func encodeBlock(dst, src []byte) (d int) {
+	if len(src) < minNonLiteralBlockSize {
+		return 0
+	}
+	return encodeBlockGo(dst, src)
+}
+
+// encodeBlockBetter 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.
+//
+// It also assumes that:
+//	len(dst) >= MaxEncodedLen(len(src))
+func encodeBlockBetter(dst, src []byte) (d int) {
+	return encodeBlockBetterGo(dst, src)
+}
+
+// encodeBlockBetter 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.
+//
+// It also assumes that:
+//	len(dst) >= MaxEncodedLen(len(src))
+func encodeBlockBetterSnappy(dst, src []byte) (d int) {
+	return encodeBlockBetterSnappyGo(dst, src)
+}
+
+// encodeBlock 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.
+//
+// It also assumes that:
+//	len(dst) >= MaxEncodedLen(len(src))
+func encodeBlockSnappy(dst, src []byte) (d int) {
+	if len(src) < minNonLiteralBlockSize {
+		return 0
+	}
+	return encodeBlockSnappyGo(dst, src)
+}
+
+// emitLiteral writes a literal chunk and returns the number of bytes written.
+//
+// It assumes that:
+//	dst is long enough to hold the encoded bytes
+//	0 <= len(lit) && len(lit) <= math.MaxUint32
+func emitLiteral(dst, lit []byte) int {
+	if len(lit) == 0 {
+		return 0
+	}
+	const num = 63<<2 | tagLiteral
+	i, n := 0, uint(len(lit)-1)
+	switch {
+	case n < 60:
+		dst[0] = uint8(n)<<2 | tagLiteral
+		i = 1
+	case n < 1<<8:
+		dst[1] = uint8(n)
+		dst[0] = 60<<2 | tagLiteral
+		i = 2
+	case n < 1<<16:
+		dst[2] = uint8(n >> 8)
+		dst[1] = uint8(n)
+		dst[0] = 61<<2 | tagLiteral
+		i = 3
+	case n < 1<<24:
+		dst[3] = uint8(n >> 16)
+		dst[2] = uint8(n >> 8)
+		dst[1] = uint8(n)
+		dst[0] = 62<<2 | tagLiteral
+		i = 4
+	default:
+		dst[4] = uint8(n >> 24)
+		dst[3] = uint8(n >> 16)
+		dst[2] = uint8(n >> 8)
+		dst[1] = uint8(n)
+		dst[0] = 63<<2 | tagLiteral
+		i = 5
+	}
+	return i + copy(dst[i:], lit)
+}
+
+// emitRepeat writes a repeat chunk and returns the number of bytes written.
+// Length must be at least 4 and < 1<<24
+func emitRepeat(dst []byte, offset, length int) int {
+	// Repeat offset, make length cheaper
+	length -= 4
+	if length <= 4 {
+		dst[0] = uint8(length)<<2 | tagCopy1
+		dst[1] = 0
+		return 2
+	}
+	if length < 8 && offset < 2048 {
+		// Encode WITH offset
+		dst[1] = uint8(offset)
+		dst[0] = uint8(offset>>8)<<5 | uint8(length)<<2 | tagCopy1
+		return 2
+	}
+	if length < (1<<8)+4 {
+		length -= 4
+		dst[2] = uint8(length)
+		dst[1] = 0
+		dst[0] = 5<<2 | tagCopy1
+		return 3
+	}
+	if length < (1<<16)+(1<<8) {
+		length -= 1 << 8
+		dst[3] = uint8(length >> 8)
+		dst[2] = uint8(length >> 0)
+		dst[1] = 0
+		dst[0] = 6<<2 | tagCopy1
+		return 4
+	}
+	const maxRepeat = (1 << 24) - 1
+	length -= 1 << 16
+	left := 0
+	if length > maxRepeat {
+		left = length - maxRepeat + 4
+		length = maxRepeat - 4
+	}
+	dst[4] = uint8(length >> 16)
+	dst[3] = uint8(length >> 8)
+	dst[2] = uint8(length >> 0)
+	dst[1] = 0
+	dst[0] = 7<<2 | tagCopy1
+	if left > 0 {
+		return 5 + emitRepeat(dst[5:], offset, left)
+	}
+	return 5
+}
+
+// emitCopy writes a copy chunk and returns the number of bytes written.
+//
+// It assumes that:
+//	dst is long enough to hold the encoded bytes
+//	1 <= offset && offset <= math.MaxUint32
+//	4 <= length && length <= 1 << 24
+func emitCopy(dst []byte, offset, length int) int {
+	if offset >= 65536 {
+		i := 0
+		if length > 64 {
+			// Emit a length 64 copy, encoded as 5 bytes.
+			dst[4] = uint8(offset >> 24)
+			dst[3] = uint8(offset >> 16)
+			dst[2] = uint8(offset >> 8)
+			dst[1] = uint8(offset)
+			dst[0] = 63<<2 | tagCopy4
+			length -= 64
+			if length >= 4 {
+				// Emit remaining as repeats
+				return 5 + emitRepeat(dst[5:], offset, length)
+			}
+			i = 5
+		}
+		if length == 0 {
+			return i
+		}
+		// Emit a copy, offset encoded as 4 bytes.
+		dst[i+0] = uint8(length-1)<<2 | tagCopy4
+		dst[i+1] = uint8(offset)
+		dst[i+2] = uint8(offset >> 8)
+		dst[i+3] = uint8(offset >> 16)
+		dst[i+4] = uint8(offset >> 24)
+		return i + 5
+	}
+
+	// Offset no more than 2 bytes.
+	if length > 64 {
+		// Emit a length 60 copy, encoded as 3 bytes.
+		// Emit remaining as repeat value (minimum 4 bytes).
+		dst[2] = uint8(offset >> 8)
+		dst[1] = uint8(offset)
+		dst[0] = 59<<2 | tagCopy2
+		length -= 60
+		// Emit remaining as repeats, at least 4 bytes remain.
+		return 3 + emitRepeat(dst[3:], offset, length)
+	}
+	if length >= 12 || offset >= 2048 {
+		// Emit the remaining copy, encoded as 3 bytes.
+		dst[2] = uint8(offset >> 8)
+		dst[1] = uint8(offset)
+		dst[0] = uint8(length-1)<<2 | tagCopy2
+		return 3
+	}
+	// Emit the remaining copy, encoded as 2 bytes.
+	dst[1] = uint8(offset)
+	dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
+	return 2
+}
+
+// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
+//
+// It assumes that:
+//	dst is long enough to hold the encoded bytes
+//	1 <= offset && offset <= math.MaxUint32
+//	4 <= length && length <= 1 << 24
+func emitCopyNoRepeat(dst []byte, offset, length int) int {
+	if offset >= 65536 {
+		i := 0
+		if length > 64 {
+			// Emit a length 64 copy, encoded as 5 bytes.
+			dst[4] = uint8(offset >> 24)
+			dst[3] = uint8(offset >> 16)
+			dst[2] = uint8(offset >> 8)
+			dst[1] = uint8(offset)
+			dst[0] = 63<<2 | tagCopy4
+			length -= 64
+			if length >= 4 {
+				// Emit remaining as repeats
+				return 5 + emitCopyNoRepeat(dst[5:], offset, length)
+			}
+			i = 5
+		}
+		if length == 0 {
+			return i
+		}
+		// Emit a copy, offset encoded as 4 bytes.
+		dst[i+0] = uint8(length-1)<<2 | tagCopy4
+		dst[i+1] = uint8(offset)
+		dst[i+2] = uint8(offset >> 8)
+		dst[i+3] = uint8(offset >> 16)
+		dst[i+4] = uint8(offset >> 24)
+		return i + 5
+	}
+
+	// Offset no more than 2 bytes.
+	if length > 64 {
+		// Emit a length 60 copy, encoded as 3 bytes.
+		// Emit remaining as repeat value (minimum 4 bytes).
+		dst[2] = uint8(offset >> 8)
+		dst[1] = uint8(offset)
+		dst[0] = 59<<2 | tagCopy2
+		length -= 60
+		// Emit remaining as repeats, at least 4 bytes remain.
+		return 3 + emitCopyNoRepeat(dst[3:], offset, length)
+	}
+	if length >= 12 || offset >= 2048 {
+		// Emit the remaining copy, encoded as 3 bytes.
+		dst[2] = uint8(offset >> 8)
+		dst[1] = uint8(offset)
+		dst[0] = uint8(length-1)<<2 | tagCopy2
+		return 3
+	}
+	// Emit the remaining copy, encoded as 2 bytes.
+	dst[1] = uint8(offset)
+	dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
+	return 2
+}
+
+// matchLen returns how many bytes match in a and b
+//
+// It assumes that:
+//   len(a) <= len(b)
+//
+func matchLen(a []byte, b []byte) int {
+	b = b[:len(a)]
+	var checked int
+	if len(a) > 4 {
+		// Try 4 bytes first
+		if diff := load32(a, 0) ^ load32(b, 0); diff != 0 {
+			return bits.TrailingZeros32(diff) >> 3
+		}
+		// Switch to 8 byte matching.
+		checked = 4
+		a = a[4:]
+		b = b[4:]
+		for len(a) >= 8 {
+			b = b[:len(a)]
+			if diff := load64(a, 0) ^ load64(b, 0); diff != 0 {
+				return checked + (bits.TrailingZeros64(diff) >> 3)
+			}
+			checked += 8
+			a = a[8:]
+			b = b[8:]
+		}
+	}
+	b = b[:len(a)]
+	for i := range a {
+		if a[i] != b[i] {
+			return int(i) + checked
+		}
+	}
+	return len(a) + checked
+}