bump go-store version (includes minio) (#1657)

Signed-off-by: kim <grufwub@gmail.com>

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

@@ -58,6 +58,32 @@ func Encode(dst, src []byte) []byte {
 	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) < 6 || 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.
@@ -132,7 +158,7 @@ func EncodeBest(dst, src []byte) []byte {
 		d += emitLiteral(dst[d:], src)
 		return dst[:d]
 	}
-	n := encodeBlockBest(dst[d:], src)
+	n := encodeBlockBest(dst[d:], src, nil)
 	if n > 0 {
 		d += n
 		return dst[:d]
@@ -404,10 +430,11 @@ type Writer struct {
 	buffers       sync.Pool
 	pad           int
 
-	writer   io.Writer
-	randSrc  io.Reader
-	writerWg sync.WaitGroup
-	index    Index
+	writer    io.Writer
+	randSrc   io.Reader
+	writerWg  sync.WaitGroup
+	index     Index
+	customEnc func(dst, src []byte) int
 
 	// wroteStreamHeader is whether we have written the stream header.
 	wroteStreamHeader bool
@@ -773,6 +800,9 @@ func (w *Writer) EncodeBuffer(buf []byte) (err error) {
 }
 
 func (w *Writer) encodeBlock(obuf, uncompressed []byte) int {
+	if w.customEnc != nil {
+		return w.customEnc(obuf, uncompressed)
+	}
 	if w.snappy {
 		switch w.level {
 		case levelFast:
@@ -790,7 +820,7 @@ func (w *Writer) encodeBlock(obuf, uncompressed []byte) int {
 	case levelBetter:
 		return encodeBlockBetter(obuf, uncompressed)
 	case levelBest:
-		return encodeBlockBest(obuf, uncompressed)
+		return encodeBlockBest(obuf, uncompressed, nil)
 	}
 	return 0
 }
@@ -1339,3 +1369,15 @@ func WriterFlushOnWrite() WriterOption {
 		return nil
 	}
 }
+
+// WriterCustomEncoder allows to override the encoder for blocks on the stream.
+// The function must compress 'src' into 'dst' and return the bytes used in dst as an integer.
+// Block size (initial varint) should not be added by the encoder.
+// Returning value 0 indicates the block could not be compressed.
+// The function should expect to be called concurrently.
+func WriterCustomEncoder(fn func(dst, src []byte) int) WriterOption {
+	return func(w *Writer) error {
+		w.customEnc = fn
+		return nil
+	}
+}