1 files changed, 393 insertions, 0 deletions

diff --git a/vendor/github.com/klauspost/compress/s2/encode.go b/vendor/github.com/klauspost/compress/s2/encode.go
new file mode 100644
index 0000000..0c9088a
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/s2/encode.go
@@ -0,0 +1,393 @@
+// Copyright 2011 The Snappy-Go Authors. All rights reserved.
+// Copyright (c) 2019 Klaus Post. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package s2
+
+import (
+        "encoding/binary"
+        "math"
+        "math/bits"
+)
+
+// Encode returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+//
+// The blocks will require the same amount of memory to decode as encoding,
+// and does not make for concurrent decoding.
+// Also note that blocks do not contain CRC information, so corruption may be undetected.
+//
+// If you need to encode larger amounts of data, consider using
+// the streaming interface which gives all of these features.
+func Encode(dst, src []byte) []byte {
+        if n := MaxEncodedLen(len(src)); n < 0 {
+                panic(ErrTooLarge)
+        } else if cap(dst) < n {
+                dst = make([]byte, n)
+        } else {
+                dst = dst[:n]
+        }
+
+        // The block starts with the varint-encoded length of the decompressed bytes.
+        d := binary.PutUvarint(dst, uint64(len(src)))
+
+        if len(src) == 0 {
+                return dst[:d]
+        }
+        if len(src) < minNonLiteralBlockSize {
+                d += emitLiteral(dst[d:], src)
+                return dst[:d]
+        }
+        n := encodeBlock(dst[d:], src)
+        if n > 0 {
+                d += n
+                return dst[:d]
+        }
+        // Not compressible
+        d += emitLiteral(dst[d:], src)
+        return dst[:d]
+}
+
+// EstimateBlockSize will perform a very fast compression
+// without outputting the result and return the compressed output size.
+// The function returns -1 if no improvement could be achieved.
+// Using actual compression will most often produce better compression than the estimate.
+func EstimateBlockSize(src []byte) (d int) {
+        if len(src) <= inputMargin || int64(len(src)) > 0xffffffff {
+                return -1
+        }
+        if len(src) <= 1024 {
+                d = calcBlockSizeSmall(src)
+        } else {
+                d = calcBlockSize(src)
+        }
+
+        if d == 0 {
+                return -1
+        }
+        // Size of the varint encoded block size.
+        d += (bits.Len64(uint64(len(src))) + 7) / 7
+
+        if d >= len(src) {
+                return -1
+        }
+        return d
+}
+
+// EncodeBetter returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// EncodeBetter compresses better than Encode but typically with a
+// 10-40% speed decrease on both compression and decompression.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+//
+// The blocks will require the same amount of memory to decode as encoding,
+// and does not make for concurrent decoding.
+// Also note that blocks do not contain CRC information, so corruption may be undetected.
+//
+// If you need to encode larger amounts of data, consider using
+// the streaming interface which gives all of these features.
+func EncodeBetter(dst, src []byte) []byte {
+        if n := MaxEncodedLen(len(src)); n < 0 {
+                panic(ErrTooLarge)
+        } else if len(dst) < n {
+                dst = make([]byte, n)
+        }
+
+        // The block starts with the varint-encoded length of the decompressed bytes.
+        d := binary.PutUvarint(dst, uint64(len(src)))
+
+        if len(src) == 0 {
+                return dst[:d]
+        }
+        if len(src) < minNonLiteralBlockSize {
+                d += emitLiteral(dst[d:], src)
+                return dst[:d]
+        }
+        n := encodeBlockBetter(dst[d:], src)
+        if n > 0 {
+                d += n
+                return dst[:d]
+        }
+        // Not compressible
+        d += emitLiteral(dst[d:], src)
+        return dst[:d]
+}
+
+// EncodeBest returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// EncodeBest compresses as good as reasonably possible but with a
+// big speed decrease.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+//
+// The blocks will require the same amount of memory to decode as encoding,
+// and does not make for concurrent decoding.
+// Also note that blocks do not contain CRC information, so corruption may be undetected.
+//
+// If you need to encode larger amounts of data, consider using
+// the streaming interface which gives all of these features.
+func EncodeBest(dst, src []byte) []byte {
+        if n := MaxEncodedLen(len(src)); n < 0 {
+                panic(ErrTooLarge)
+        } else if len(dst) < n {
+                dst = make([]byte, n)
+        }
+
+        // The block starts with the varint-encoded length of the decompressed bytes.
+        d := binary.PutUvarint(dst, uint64(len(src)))
+
+        if len(src) == 0 {
+                return dst[:d]
+        }
+        if len(src) < minNonLiteralBlockSize {
+                d += emitLiteral(dst[d:], src)
+                return dst[:d]
+        }
+        n := encodeBlockBest(dst[d:], src, nil)
+        if n > 0 {
+                d += n
+                return dst[:d]
+        }
+        // Not compressible
+        d += emitLiteral(dst[d:], src)
+        return dst[:d]
+}
+
+// EncodeSnappy returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// The output is Snappy compatible and will likely decompress faster.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+//
+// The blocks will require the same amount of memory to decode as encoding,
+// and does not make for concurrent decoding.
+// Also note that blocks do not contain CRC information, so corruption may be undetected.
+//
+// If you need to encode larger amounts of data, consider using
+// the streaming interface which gives all of these features.
+func EncodeSnappy(dst, src []byte) []byte {
+        if n := MaxEncodedLen(len(src)); n < 0 {
+                panic(ErrTooLarge)
+        } else if cap(dst) < n {
+                dst = make([]byte, n)
+        } else {
+                dst = dst[:n]
+        }
+
+        // The block starts with the varint-encoded length of the decompressed bytes.
+        d := binary.PutUvarint(dst, uint64(len(src)))
+
+        if len(src) == 0 {
+                return dst[:d]
+        }
+        if len(src) < minNonLiteralBlockSize {
+                d += emitLiteral(dst[d:], src)
+                return dst[:d]
+        }
+
+        n := encodeBlockSnappy(dst[d:], src)
+        if n > 0 {
+                d += n
+                return dst[:d]
+        }
+        // Not compressible
+        d += emitLiteral(dst[d:], src)
+        return dst[:d]
+}
+
+// EncodeSnappyBetter returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// The output is Snappy compatible and will likely decompress faster.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+//
+// The blocks will require the same amount of memory to decode as encoding,
+// and does not make for concurrent decoding.
+// Also note that blocks do not contain CRC information, so corruption may be undetected.
+//
+// If you need to encode larger amounts of data, consider using
+// the streaming interface which gives all of these features.
+func EncodeSnappyBetter(dst, src []byte) []byte {
+        if n := MaxEncodedLen(len(src)); n < 0 {
+                panic(ErrTooLarge)
+        } else if cap(dst) < n {
+                dst = make([]byte, n)
+        } else {
+                dst = dst[:n]
+        }
+
+        // The block starts with the varint-encoded length of the decompressed bytes.
+        d := binary.PutUvarint(dst, uint64(len(src)))
+
+        if len(src) == 0 {
+                return dst[:d]
+        }
+        if len(src) < minNonLiteralBlockSize {
+                d += emitLiteral(dst[d:], src)
+                return dst[:d]
+        }
+
+        n := encodeBlockBetterSnappy(dst[d:], src)
+        if n > 0 {
+                d += n
+                return dst[:d]
+        }
+        // Not compressible
+        d += emitLiteral(dst[d:], src)
+        return dst[:d]
+}
+
+// EncodeSnappyBest returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// The output is Snappy compatible and will likely decompress faster.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+//
+// The blocks will require the same amount of memory to decode as encoding,
+// and does not make for concurrent decoding.
+// Also note that blocks do not contain CRC information, so corruption may be undetected.
+//
+// If you need to encode larger amounts of data, consider using
+// the streaming interface which gives all of these features.
+func EncodeSnappyBest(dst, src []byte) []byte {
+        if n := MaxEncodedLen(len(src)); n < 0 {
+                panic(ErrTooLarge)
+        } else if cap(dst) < n {
+                dst = make([]byte, n)
+        } else {
+                dst = dst[:n]
+        }
+
+        // The block starts with the varint-encoded length of the decompressed bytes.
+        d := binary.PutUvarint(dst, uint64(len(src)))
+
+        if len(src) == 0 {
+                return dst[:d]
+        }
+        if len(src) < minNonLiteralBlockSize {
+                d += emitLiteral(dst[d:], src)
+                return dst[:d]
+        }
+
+        n := encodeBlockBestSnappy(dst[d:], src)
+        if n > 0 {
+                d += n
+                return dst[:d]
+        }
+        // Not compressible
+        d += emitLiteral(dst[d:], src)
+        return dst[:d]
+}
+
+// ConcatBlocks will concatenate the supplied blocks and append them to the supplied destination.
+// If the destination is nil or too small, a new will be allocated.
+// The blocks are not validated, so garbage in = garbage out.
+// dst may not overlap block data.
+// Any data in dst is preserved as is, so it will not be considered a block.
+func ConcatBlocks(dst []byte, blocks ...[]byte) ([]byte, error) {
+        totalSize := uint64(0)
+        compSize := 0
+        for _, b := range blocks {
+                l, hdr, err := decodedLen(b)
+                if err != nil {
+                        return nil, err
+                }
+                totalSize += uint64(l)
+                compSize += len(b) - hdr
+        }
+        if totalSize == 0 {
+                dst = append(dst, 0)
+                return dst, nil
+        }
+        if totalSize > math.MaxUint32 {
+                return nil, ErrTooLarge
+        }
+        var tmp [binary.MaxVarintLen32]byte
+        hdrSize := binary.PutUvarint(tmp[:], totalSize)
+        wantSize := hdrSize + compSize
+
+        if cap(dst)-len(dst) < wantSize {
+                dst = append(make([]byte, 0, wantSize+len(dst)), dst...)
+        }
+        dst = append(dst, tmp[:hdrSize]...)
+        for _, b := range blocks {
+                _, hdr, err := decodedLen(b)
+                if err != nil {
+                        return nil, err
+                }
+                dst = append(dst, b[hdr:]...)
+        }
+        return dst, nil
+}
+
+// inputMargin is the minimum number of extra input bytes to keep, inside
+// encodeBlock's inner loop. On some architectures, this margin lets us
+// implement a fast path for emitLiteral, where the copy of short (<= 16 byte)
+// literals can be implemented as a single load to and store from a 16-byte
+// register. That literal's actual length can be as short as 1 byte, so this
+// can copy up to 15 bytes too much, but that's OK as subsequent iterations of
+// the encoding loop will fix up the copy overrun, and this inputMargin ensures
+// that we don't overrun the dst and src buffers.
+const inputMargin = 8
+
+// minNonLiteralBlockSize is the minimum size of the input to encodeBlock that
+// will be accepted by the encoder.
+const minNonLiteralBlockSize = 32
+
+const intReduction = 2 - (1 << (^uint(0) >> 63)) // 1 (32 bits) or 0 (64 bits)
+
+// MaxBlockSize is the maximum value where MaxEncodedLen will return a valid block size.
+// Blocks this big are highly discouraged, though.
+// Half the size on 32 bit systems.
+const MaxBlockSize = (1<<(32-intReduction) - 1) - binary.MaxVarintLen32 - 5
+
+// MaxEncodedLen returns the maximum length of a snappy block, given its
+// uncompressed length.
+//
+// It will return a negative value if srcLen is too large to encode.
+// 32 bit platforms will have lower thresholds for rejecting big content.
+func MaxEncodedLen(srcLen int) int {
+        n := uint64(srcLen)
+        if intReduction == 1 {
+                // 32 bits
+                if n > math.MaxInt32 {
+                        // Also includes negative.
+                        return -1
+                }
+        } else if n > 0xffffffff {
+                // 64 bits
+                // Also includes negative.
+                return -1
+        }
+        // Size of the varint encoded block size.
+        n = n + uint64((bits.Len64(n)+7)/7)
+
+        // Add maximum size of encoding block as literals.
+        n += uint64(literalExtraSize(int64(srcLen)))
+        if intReduction == 1 {
+                // 32 bits
+                if n > math.MaxInt32 {
+                        return -1
+                }
+        } else if n > 0xffffffff {
+                // 64 bits
+                // Also includes negative.
+                return -1
+        }
+        return int(n)
+}